Biomedical subjects

Tao Liang

Publications and source records attributed to Tao Liang.

At least 19 recordsLinked to original sources

PubMed2025

Acetyl-CoA synthetase mutations affect the susceptibility of Plasmodium falciparum to antimalarial drugs.

Plasmodium falciparum acetyl-CoA synthetase (PfAcAS) is an important source of acetyl-CoA. We detected mutations S868G and V950I in PfAcAS by whole-genome sequencing analysis in certain recrudescent parasites after treatment with artesunate and dihydroartemisinin-piperaquine. Using CRISPR/Cas9 technology, we engineered parasite lines to carry the PfAcAS S868G and V950I mutations in two genetic backgrounds and evaluated their susceptibilities to antimalarial drugs in vitro. The results demonstrated that PfAcAS S868G and V950I mutations alone or in combination affected the susceptibility of P. falciparum to several antimalarial drugs, including the artemisinin derivatives (dihydroartemisinin, artesunate, and artemether) and chloroquine, although absolute changes in susceptibilities were modest.IMPORTANCEMalaria, an infectious disease caused by Plasmodium parasites and transmitted by mosquitoes, continues to be one of the most pressing public health challenges worldwide. P. falciparum has demonstrated reduced sensitivity to artemisinin-based combination therapies (ACTs), thereby intensifying the difficulties associated with malaria management. Currently, only a limited number of molecular markers exist for identifying drug resistance in P. falciparum, and these markers do not fully elucidate the mechanisms behind this resistance. In this study, we performed whole-genome sequencing analysis on P. falciparum strains that reemerged following ACT treatment. We aim to identify molecules potentially associated with drug resistance, which may provide new molecular markers for monitoring drug resistance in P. falciparum.

Plasmodium falciparum↗

PubMed2007

Simulating the temporal changes of OCP pollution in Hangzhou, China.

A dynamic fugacity model was applied to simulate the changes of contents and transfer fluxes of hexachlorocyclohexane (HCHs) and dichloro-diphenyl-trichloroethane (DDTs) from 1950s in the environment of Hangzhou, China. The receptors are composed of air, surface water, soils, sediment and biota compartments. The model provides a method to combine loadings of HCHs and DDTs from various sources with a series of physical-chemical processes to estimate concentrations and transport fluxes of HCHs and DDTs. Model results suggested that the calculated concentrations were in line with the observed ones. The highest contents of HCH and DDT in the environment of study area were 523 t and 471 t before 1983, among which about 80.7% HCHs and 93.2% DDTs remained in the soil compartment. From 1984 to now, contents of HCHs and DDTs had decreased to about 0.07% and 0.40% of their highest amount (before 1983), and only about 0.001% and 0.014% will expect to be left in 2020 in the study area according to the model prediction. Before 1983, the main transfer fluxes of HCHs were deposition from air to soil, runoff from soil to water and diffusion from soil to air, but for DDTs the main transfer fluxes were deposition from air to soil and water, and transfer from water to sediment. From 1984 to now, runoff from soil to water and transfer from water to sediment became the dominant processes. Although a large amount of HCHs and DDTs had been applied to the study area, their residue levels in the soils were much lower than those in North China (had lesser HCHs and DDTs application than in South China) at present time, and close to other locations of South China (had similar HCHs and DDTs application level). It can be attributed to the high precipitation and temperature that enhances the processes of wet deposition, evaporation and degradation of OCPs. Sensitivities of the input parameters to the calculated concentrations were evaluated using coefficient-of-variation normalized sensitivity coefficients. The model was also subjected to uncertainty analyses using a Monte Carlo simulation.

Air Pollutants↗

PubMed2006

Effects of organic ligands on fractionation of rare earth elements (REEs) in hydroponic plants: an application to the determination of binding capacities by humic acid for modeling.

Previous studies have revealed the fractionation processes of rare earth elements (REEs) in hydroponic plants, with a heavy REE (HREE, the elements from Gd to Lu) enrichment in leaves. In this study, effects on the HREE enrichment in soybean leaves with additions of carboxylic acids (acetate, malate, citrate, NTA, EDTA and DTPA) and two soil humic acids (HAs) were investigated. REE speciation in carboxylic acid and HA solutions was simulated using Visual MINTEQ and Model V, respectively. The results showed that the effects caused by carboxylic acids were strongly dependent on the differences between their binding strengths for light REEs (LREEs, the elements from La to Eu) and those for HREEs. A good correlation existed between these effects and the changes of free REE ions in solutions. This relationship was also observed for the HA treatments, provided that the intrinsic equilibrium constants of REEs for cation-proton exchange with HA (i.e., pK(MHA)) in Model V were estimated using a free-energy relationship with the stability constants for REE complexation with lactic acid. It is suggested that this set of pK(MHA) values is more suitable for use in Model V for the simulation of REE complexation with HA.

Humic Substances↗

PubMed2006

Human neural stem cells promote corticospinal axons regeneration and synapse reformation in injured spinal cord of rats.

BACKGROUND: Axonal regeneration in lesioned mammalian central nervous system is abortive, and this causes permanent disabilities in individuals with spinal cord injuries. This paper studied the action of neural stem cell (NSC) in promoting corticospinal axons regeneration and synapse reformation in rats with injured spinal cord. METHODS: NSCs were isolated from the cortical tissue of spontaneous aborted human fetuses in accordance with the ethical request. The cells were discarded from the NSC culture to acquire NSC-conditioned medium. Sixty adult Wistar rats were randomly divided into four groups (n = 15 in each): NSC graft, NSC medium, graft control and medium control groups. Microsurgical transection of the spinal cord was performed in all the rats at the T11. The NSC graft group received stereotaxic injections of NSCs suspension into both the spinal cord stumps immediately after transection; graft control group received DMEM injection. In NSC medium group, NSC-conditioned medium was administered into the spinal cord every week; NSC culture medium was administered to the medium control group. Hindlimb motor function was assessed using the BBB Locomotor Rating Scale. Regeneration of biotin dextran amine (BDA) labeled corticospinal tract was assessed. Differentiation of NSCs and the expression of synaptophysin at the distal end of the injured spinal cord were observed under a confocal microscope. Group comparisons of behavioral data were analyzed with ANOVA. RESULTS: NSCs transplantation resulted in extensive growth of corticospinal axons and locomotor recovery in adult rats after complete spinal cord transection, the mean BBB scores reached 12.5 in NSC graft group and 2.5 in graft control group (P < 0.05). There was also significant difference in BBB score between the NSC medium (11.7) and medium control groups (3.7, P < 0.05). BDA traces regenerated fibers sprouted across the lesion site and entered the caudal part of the spinal cord. Synaptophysin expression colocalized with BDA positive axons and neurons distal to the injury site. Transplanted cells were found to migrate into the lesion, but not scatter along the route of axon grows. The cells differentiated into astrocytes or oligodendrocytes, but not into the neurons after transplantation. Furthermore, NSC medium administration did not limit the degree of axon sprouting and functional recovery of the injured rats compared to the NSC graft group. CONCLUSIONS: Human embryonic neural stem cells can promote functional corticospinal axons regeneration and synapse reformation in the injured spinal cord of rats. The action is mainly through the nutritional effect of the stem cells on the spinal cord.

Animals↗

PubMed2006

Fractionation mechanisms of rare earth elements (REEs) in hydroponic wheat: an application for metal accumulation by plants.

Fractionations of rare earth elements (REEs) in wheat (Triticum aestivum L.) were observed through application of exogenous mixed REEs under hydroponic conditions. Middle REE (MREE), light REE (LREE), and heavy REE (HREE) enrichments were found in roots, stems, and leaves, respectively, accompanied by the tetrad effect (an effect that can cause a split of REE patterns into four consecutive segments) in these organs. Investigations into REE speciation in roots and in the xylem sap with X-ray absorption spectroscopy (XAS) and nanometer-sized TiO2 adsorption techniques, associated with other controlled experiments, demonstrated that REE fractionations in wheat were caused by the combined effects of chemical precipitation, cell wall absorption, and solution complexation by organic ligands in the xylem vessels. REE fractionations in wheat, which were derived from the small differences of chemical properties across REE series, may reflect a sensitive internal chemical environment that influences plant accumulation for REEs and their analogues actinide radionuclides.

Adsorption↗

PubMed2006

Spontaneous curvature cancellation in forced thin sheets.

In this paper we report numerically observed spontaneous vanishing of mean curvature on a developable cone made by pushing a thin elastic sheet into a circular container [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, Nature (London) 401 46 (1999)]. We show that this feature is independent of thickness of the sheet, the supporting radius, and the amount of deflection. Several variants of the developable cone are studied to examine the necessary conditions that lead to the vanishing of mean curvature. It is found that the presence of appropriate amount of radial stress is necessary. The developable cone geometry somehow produces the right amount of radial stress to induce just enough radial curvature to cancel the conical azimuthal curvature. In addition, the circular symmetry of supporting container edge plays an important role. With an elliptical supporting edge, the radial curvature overcompensates the azimuthal curvature near the minor axis and undercompensates near the major axis. Our numerical finding is verified by a crude experiment using a reflective plastic sheet. We expect this finding to have broad importance in describing the general geometrical properties of forced crumpling of thin sheets.

Journal Article↗

PubMed2006

New minimally invasive technique to occlude secundum atrial septal defect in 53 patients.

BACKGROUND: Conventional surgical atrial septal defect (ASD) closure requires cardiopulmonary bypass, whereas percutaneous transcatheter closure is limited by maximal defect size of 34 mm and access to the neck. We describe a new minimally invasive approach using a right minithoracotomy to deploy an occluder without cardiopulmonary bypass. METHODS: Between October 2004 and April 2005, 53 secundum ASDs were closed by this method. Through a 3-cm incision in the right fourth intercostal space, a minithoracotomy exposes the right atrium to facilitate deployment of the septal closure device. The age of the patients was from 2 to 61 years. The ASD size was 12 to 39 mm. RESULTS: All ASDs were successfully closed with a mean device size of 33.1 +/- 8 mm (range, 16 to 46 mm). The procedure duration was 30 to 60 minutes. All patients were extubated on table, with less than a 1-day stay in the intensive care unit. The hospital stay was 3 to 7 days. There was no postoperative mortality. At mean follow-up of 1 to 8 months, there were no major morbidities. One patient had minimal residual shunt that resolved 1 month later. CONCLUSIONS: This new minimally invasive method of secundum ASD closure is safe and cosmetically superior to conventional surgery. Early results are encouraging.

Adolescent↗

PubMed2006

A clinical application of laser direction in anastomosis for inferior canalicular laceration.

OBJECTIVE: To study the therapeutic efficiency and efficacy of laser-directing approach on searching for the nasal broken end of lacerated lacrimal canaliculus in anastomosis for canalicular laceration. METHODS: Forty-nine patients (49 eyes) suffering from traumatic inferior canalicular laceration were divided into control group and laser-directing group. The distance between the lacrimal punctum and the nasal broken end of lacerated lacrimal canaliculus was more than 6 mm. During the course of management of eyelid trauma, the patients were treated by canalicular anastomosis operation with traditional method and laser-directing method in searching for the nasal broken end of lacerated lacrimal canaliculus respectively. The silicone tube of 1 mm diameter was intubated in the lacrimal passage as a stent for 4 to 6 months. RESULTS: In the laser-directing group, the mean time in searching for the nasal broken end of lacerated lacrimal canaliculus was (5.75+/-1.49) minutes and the mean time of operation was (49.21+/-3.37) minutes; both were significantly shorter than that of the control group (P<0.01). The cure rate of the laser-directing group was 96.55%, higher than that of the control group but without statistical significance (P>0.05). CONCLUSIONS: The laser-directing method is much quicker and more convenient to searching for the nasal broken end of the lacerated lacrimal canaliculus than the traditional approach, and patients suffer less pain and damaging in canalicular anastomosis operation.

Adolescent↗

PubMed2006

[Contents and distribution characteristics of heavy metals in water and sediment of intertidalite].

ICP-MS analytical technology was used to analyze the concentration of 13 heavy metals in surface water, pore water in sediment, suspended particulate matter, and sediment of intertidalite of Tianjin. Results show that both total amount and single concentration of heavy metals vary greatly in different media, the biggest and smallest values differ by 4 or 7 magnitudes. While the variation coefficients of the contents of total metals or single metal in the same medium are less than 0.3 and 0.5 respectively except for the pore water. The average concentration of total dissolved heavy metals is 41.2 microg x L(-1), while total contents of heavy metals in original water, pore water, sediment and suspended particles are 62.7 microg x L(-1), 112.7 microg x L(-1), 262.3 mg x L(-1) and 345.0 mg x L(-1) respectively, they are similar to inland natural river but higher then those of ocean. The composition of heavy metals in different media varied greatly, metals prone to dissolve such as Mo account for more than 20% in water, but metals uneasy to dissolve mainly exist in sediment and suspended particles and absorbed by particles. Typical heavy metals, such as Zn, Cu, Pb and Cr, account for 40% - 50% in water and 50% - 80% in other media. The similarity in distribution mode of heavy metals in intertidalite and terrestrial soil suggest that they are originated from terrestrial soil that is contiguity to the sea. Notable correlativity can be seen between concentrations of all heavy metals except for Mo in sediment, which can explain the similarity of their environmental behavior, but only wake correlation between the content of organic carbon and concentrations of heavy metals in suspended particulates and sediment.

China↗

PubMed2006

Clinical analysis of hydroxyapatite orbital implantation after ocular trauma in 211 cases.

OBJECTIVE: To evaluate the therapeutic effects and complications of hydroxyapatite (HA) orbital implantation on patients after trauma-related surgeries. METHODS: Retrospective analysis was made from 211 cases (211 eyes) who underwent HA orbital implant placement after trauma-related enucleation or evisceration, including 68 cases of evisceration and primary HA implant placement, 77 cases of enucleation and HA implant placement wrapped with multi-windowed sclera, 66 cases of enucleation and HA implant placement free of wrapping. All the cases were followed up for 1-5 years to observe the therapeutic effects and major complications. RESULTS: Five of 211 cases had wound dehiscence. Ten cases had HA implants exposure, including 1 case suffering severe orbital infection and requiring HA implant removal. The implants exposure incidences by the three surgical methods were from 1.30% to 10.06% and averaged 4.74%. Significant difference was found in late exposure incidence and total incidence from the three methods (chi(2)=13.372, P < 0.01 and chi(2)=7.540, P < 0.05). Two cases had shrinkage of the lower fornix. Enophthalmos occurred in 1 case treated by method 1 and was corrected by implanting porous polyethylene (Medpor) plate into the bottom of orbit. In 210 cases, the artificial eye moved well and the cosmetic results were satisfactory. CONCLUSIONS: Different surgical methods have their own merit and disadvantage. Enucleation and placement of HA implant wrapped with multi-windowed sclera has corroborated fewer complications than others.

Adult↗

PubMed2006

[Research on dissolved nitrogen and phosphorus loading model based on GIS].

In order to research the origin of nonpoint source pollution dissolved nitrogen (DN) and dissolved phosphorus (DP), some artificial rainfall experiments was made at Guanting Reservoir. The experimental data show that the correlation between transporting rate of DN (DP) and the runoff is very good, with the average correlation coefficient 0.9978 and 0.9889 for DN and DP respectively. Therefore, a new load model of DN(DP) is put forward. While applying it, we studied the spatial distribution of DN (DP) pollution load according to the digital elevation model (DEM) and the information obtained from land use map and soil map. Its results show that DN mainly originated from irrigable land first, mound and hill second.

Geographic Information Systems↗

PubMed2005

Accumulation and fractionation of rare earth elements (REEs) in wheat: controlled by phosphate precipitation, cell wall absorption and solution complexation.

Previous studies on rare earth element (REE) bioaccumulation have focused on their accumulation rate and fractionation, but the processes involved remain unclear. In this study, the accumulation and fractionation of REEs in wheat (Triticum aestivum L.) were investigated using solution culture with exogenous mixed REEs. A decrease in REE contents was observed from the roots to the tops of wheat. Significant fractionations of REEs were found in wheat organs as compared to the exogenous mixed REEs. Middle REE (MREE, the elements from Sm to Gd) enrichment and an M-type tetrad effect (an effect that can cause a split of REE patterns into four consecutive convex segments) were observed in the roots, which were probably caused by phosphate precipitation of REEs in/on the roots and absorption of REEs to root cell walls. Light REE (LREE, the elements from La to Eu) and heavy REE (HREE, the elements from Gd to Lu) enrichments were observed in the stems and leaves, respectively, accompanied by conspicuous W-type tetrad effects (an opposite effect to the M-type tetrad effect) in the REE patterns. HREE enrichment decreased from the older to the younger leaves and increased upwards within a single leaf. It is suggested that the solution complexation that occurred in the xylem vessels plays an important role in REE fractionations in the above-ground parts of wheat.

Cell Wall↗

PubMed2005

Crescent singularities in crumpled sheets.

We examine the crescent singularity of a developable cone in a setting similar to that studied by Cerda et al., [Nature (London) 401, 46 (1999)]. Stretching is localized in a core region near the pushing tip and bending dominates the outer region. Two types of stresses in the outer region are identified and shown to scale differently with the distance to the tip. Energies of the d cone are estimated and the conditions for the scaling of core region size Rc are discussed. Tests of the pushing force equation and direct geometrical measurements provide numerical evidence that core size scales as Rc approximately h(1/3)R(2/3), where h is the thickness of sheet and R is the supporting container radius, in agreement with the proposition of Cerda et al. We give arguments that this observed scaling law should not represent the asymptotic behavior. Other properties are also studied and tested numerically, consistent with our analysis.

Journal Article↗

PubMed2005

Environmental biogeochemical behaviors of rare earth elements in soil-plant systems.

With the continual increase in the utilization of rare earth elements (REEs) for industrial and agricultural purposes in China, the research into the environmental biogeochemical behavior of REEs has become a pressing issue. The REEs' content in soil and various parts of wheat under different conditions in soil-plant systems were measured by INAA and ICP-MS. The results showed four aspects. (1) The mean value of total REEs in soil of China was 176.8 mg kg(-1). The mean ratio of SigmaLREE/SigmaHREE in soils was 8.0 and cerium accounts for 42% of the total REEs. The content of REEs in wheat seed ranged between 10(-11) and 10(-8) g g(-1), 3-4 orders of magnitude lower than that in soil. (2) The REEs contents in ryegrass, especially in roots, were significantly related to that of soil. The bioavailability of REEs in soil mainly depended on the exchangeable fraction of REEs, which was strongly affected by the physico-chemical properties of the soil. (3) Long-term foliage-dressing with Changle microfertilizer of REEs did not affect the contents and distribution patterns of REEs in soil. At the maturing stage of spring wheat, the REEs content was in the order of root > leaf >stem and crust. Compared with the control, foliage-dressing has a higher accumulation of REEs in root and leaf. However, no significant difference was found in stem and crust between the two treatments. (4) There was no significant accumulation with the soil-dressing method. When comparing controls in both foliage- and soil-dressing methods, no distinct residue of REEs in grains was found.

Fertilizers↗

PubMed2005

Role of ligands in accumulation and fractionation of rare Earth elements in plants: examples of phosphate and citrate.

Few studies have been carried out on the effects of ligands on rare earth element (REE) bioaccumulation processes. In this study, the effects of phosphate (Pi, an inorganic ligand) and citrate (an organic ligand) on accumulation and fractionation of REEs in wheat were investigated using aqueous culture with extraneous mixed REEs (MRE). The results show that initial Pi solution culture at various levels followed by exposure to a fixed-MRE solution did not significantly change the total concentrations of REEs (SigmaREE) in roots, whereas the SigmaREE in leaves dramatically decreased with increasing levels of Pi applied. Simultaneous culture of wheat with mixture of MRE and citrate solutions caused obvious decreases of the SigmaREE in both roots and leaves. Compared with MRE, significant fractionations of REEs were found in wheat organs when no ligand was applied. Notable middle REE (MREE) enrichment and M-type tetrad effect were observed in the roots, and heavy REE (HREE) enrichment and W-type tetrad effect existed in the leaves. Pi treatments did not significantly affect the fractionations of REEs in the roots, but enrichment of HREEs in the leaves slightly increased at the highest level of Pi applied. Fractionations of REEs in both roots and leaves decreased with increasing levels of citrate applied; at higher levels of citrate (> or =150 microM), no above fractionation features were observed in wheat, but light REE (LREE) enrichment existed in the roots and leaves. The results indicate that ligands might play important roles in accumulation and fractionation of REEs during bioaccumulation processes.

Citrates↗

PubMed2005

[Influence of PO4(3-) and citrate on REE accumulation and fractionation in wheat].

This paper has studied the influence of phosphate (Pi, one of inorganic ligands) and citrate (Cit, one of organic ligands) on accumulation and fractionation of REEs in wheat based on aqueous culture, added with extraneous mixed REEs (MRE) and ICP-MS analysis technology. The results show that initial phosphate (Pi) solution of different levels followed by exposure to fixed-MRE solution has no significant effects on accumulation of the total concentrations of REEs (sigma REE) in the wheat roots, but it decrease the REE dramatically in the wheat leaves. Simultaneous culture of wheat with mixture of MRE and citrate solution caused obvious decreases of the sigma REE both in wheat roots and leaves. Compared to the control (no Pi or citrate was added), the distribution and fractionation characters of MRE had M-type tetrad effect and MREE enrichment in wheat roots, and W-type tetrad effect and HREE enrichment in wheat leaves. Different levels of Pi had no significant effects on the tetrad effect of MRE, but it notable increased the enrichment of HREE in wheat leaves. Added with citrate of different levels led the fractionation of REE decreasing gradually in wheat roots and leaves, as the concentration of citrate > or = 150 micromol x L(-1), light REE (LREE) enrichment both existed in the roots and leaves.

Citric Acid↗

PubMed2003

Animal study on expression of laminin and fibronectin in cornea during wound healing following alkali burn.

OBJECTIVE: To observe the expression of laminin and fibronectin in alkali-burned corneas in rats. METHODS: A total of 18 normal Wistar rats were randomly divided into 6 groups (n = 3 in each group). For each rat, one eye was injured by alkali burn, the other one was taken as the normal control. Then all the corneas were surgically removed and the expression of laminin and fibronectin was observed with immunohistochemistry respectively at 7 hours, 1 day, 3 days, 7 days, 14 days and 28 days after alkali burn. RESULTS: Compared with that of the normal controls, the expression of laminin and fibronectin of the burned eyes was dramatically higher at 7 hours, reached peak at 14 days and decreased to the normal level at 28 days after alkali burn. CONCLUSIONS: In the process of wound healing after alkali burn, the expression of laminin and fibronectin increases dramatically, which suggests that laminin and fibronectin may participate in the process of corneal wound healing.

Animals↗

PubMed2003

[Characteristics of phosphorous losses in surface runoff and sediment under different land use in west Tiaoxi catchment].

Five typical land covers in West Tiaoxi catchment were studied on phosphorous loss in artificial rainstorm runoff. Triple duplication experiments were carried out under the artificial rain condition with intensity of 2 mm.min-1 lasting 32 minutes in 3 m2 plot. Transportation and flux of various species of phosphorous in runoff and sediments were investigated. The results showed that phosphorous losses amount and rate were different among five types of land covers. The loss of total phosphorous in runoff of mulberry garden was the largest, which was five times higher than that of paddy and pinery field. The majority of total phosphorous in runoff was particulate phosphorous. Losses of dissolved phosphorous in vegetable plots and mulberry gardens were much higher than bamboo plot and paddy field. Loss of dissolved inorganic phosphorous in runoff was the main part of dissolved phosphorus, which pinery was much higher than others. Total amounts of phosphorous loss from top 10 cm layer of 5 kinds of soils were estimated as high as 2.57-4.89 g.m-2, of which phosphorous loss through sediment of runoff accounted for more than 97%. The rate of total phosphorous losses were ranged in 0.45-4.11 mg.(m2.min)-1 in runoff, which was much lower than that of 72.82-135.96 mg.(m2.min)-1 in sediment of runoff.

China↗