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117 results on '"Duan, S. P."'

2. Hybridization and Correlation between f- and d-orbital electrons in a valence fluctuating compound EuNi2P2

Author

Yin, Z. X., Du, X., Cao, W. Z., Jiang, J., Chen, C., Duan, S. R., Zhou, J. S., Gu, X., Xu, R. Z., Zhang, Q. Q., Zhao, W. X., Li, Y. D., Yang, Yi-feng, Yang, H. F., Liang, A. J., Liu, Z. K., Yao, H., Qi, Y. P., Chen, Y. L., and Yang, L. X.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The interaction between localized f and itinerant conduction electrons is crucial in the electronic properties of heavy fermion and valence fluctuating compounds. Using high-resolution angle-resolved photoemission spectroscopy, we systematically investigate the electronic structure of the archetypical valence fluctuating compound EuNi2P2 that hosts multiple f electrons. At low temperatures, we reveal the hybridization between Eu 4f and Ni 3d states, which contributes to the electron mass enhancement, consistent with the periodic Anderson model. With increasing temperature, interestingly, we observe opposite temperature evolution of electron spectral function above and below the Kondo coherence temperature near 110 K, which is in contrast to the monotonic valence change and beyond the expectation of the periodic Anderson model. We argue that both f-d hybridization and correlation are imperative in the electronic properties of EuNi2P2. Our results shed light on the understanding of novel properties, such as heavy fermion behaviors and valence fluctuation, of rare-earth transition-metal intermetallic compounds with multiple f electrons.

Published
2022
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3. Hourly Warning for Strong Earthquakes

Author

Chen, T., Li, L., Zhang, X. -X., Wang, C., Jin, X. -B., Ma, Q. -M., Xu, J. -Y., He, Z. -H., Li, H., Xiao, S. -G., Wang, X. -Z., Shen, X. -H., Zhang, X. -M., Li, H. -B., Zeren, Z. -M., Huang, J. -P., Huang, F. -Q., Che, S., Zou, Z. -M., Xiong, P., Liu, J., Zhang, L. -Q., Guo, Q., Roth, I., Makhmutov, V. S., Liu, Yong, Huang, Z. -H., Luo, J., Jiang, X. -J., Dai, L., Duan, S. -P., Peng, X. -D., Hu, X., Wu, H., Ti, S., Zeng, C., Song, J. -J., Xiao, F., Guo, J. -G., Yao, L., Du, A. -M., Wei, Y., Yuan, H., Wang, S., Cui, H. -Y., Li, C., Liu, Y., Yang, J., Sun, Q., Su, J. -F., Li, W., Zhang, Y. -C., Li, D. -L., Wang, S. -H., Cai, C. -L., and Yan, G. -Q.

Subjects
Physics - Geophysics, Physics - Space Physics
Abstract

A promising perspective is presented that humans can provide hourly warning for strong land earthquakes (EQs, Ms6). Two important atmospheric electrostatic signal features are described. A table that lists 9 strong land EQs with shock time, epicenter, magnitude, weather in the region near the epicenter, precursor beginning time, and precursor duration demonstrates that at approximately several hours to one day before a strong land EQ, the weather conditions are fair near the epicenter, and an abnormal negative atmospheric electrostatic signal is very obvious. Moreover, the mechanism is explained. A method by which someone could determine the epicenter and the magnitude of a forthcoming strong EQ is suggested. Finally, the possibility of realizing hourly warning for strong land EQs in the near future is pointed out.

Published
2021

4. Spectroscopic Signature for Local-moment Magnetism in van der Waals Ferromagnet Fe$_3$GeTe$_2$

Author

Xu, X., Li, Y. W., Duan, S. R., Zhang, S. L., Chen, Y. J., Kang, L., Liang, A. J., Chen, C., Xia, W., Xu, Y., Malinowski, P., Xu, X. D., Chu, J. -H., Li, G., Guo, Y. F., Liu, Z. K., Yang, L. X., and Chen, Y. L.

Subjects
Condensed Matter - Materials Science
Abstract

The van der Waals ferromagnet Fe$_3$GeTe$_2$ has recently attracted extensive research attention due to its intertwined magnetic, electronic and topological properties. Here, using high-resolution angle-resolved photoemission spectroscopy, we systematically investigate the temperature evolution of the electronic structure of bulk Fe$_3$GeTe$_2$. We observe largely dispersive energy bands that are narrowed by a factor of 1.6 compared with ab-initio calculation. Upon heating towards the ferromagnetic transition near 225 K, we observe a massive reduction of quasiparticle coherence in a large energy range, which is attributed to the enhanced magnetic fluctuation in the system. Remarkably, the electron bands barely shift with increasing temperature, which deviates from the exchange splitting picture within the itinerant Stoner model. We argue that the local magnetic moments play a crucial role in the ferromagnetism of Fe$_3$GeTe$_2$, despite its strongly itinerant nature. Our results provide important insights into the electronic and magnetic properties of Fe$_3$GeTe$_2$ and shed light on the generic understanding of itinerant magnetism in correlated materials., Comment: 4 figures

Published
2020

5. The near surface vertical atmospheric electric field abnormality could be as a promising imminent precursor of major earthquakes

Author

Chen, T., Wu, H., Zhang, X. -X., Wang, C., Jin, X. -B., Ma, Q. -M., Xu, J. -Y., Duan, S. -P., He, Z. -H., Li, H., Xiao, S. -G., Wang, X. -Z., Shen, X. -H, Guo, Q., Roth, I., Makhmutov, V. S., Liu, Y., Luo, J., Jiang, X. -J., Dai, L., Peng, X. -D., Hu, X., Li, L., Zeng, C., Song, J. -J., Xiao, F., Guo, J. -G., Cui, H. -Y., Li, C., and Sun, Q.

Subjects
Physics - Geophysics
Abstract

A promising short term precursor of major earthquakes (EQ) is very crucial in saving people and preventing huge losses. Ez, atmospheric electrostatic field vertical component, under fair air conditions, is generally oriented downwards (positive). Anomalous negative Ez signals could be used as an indicator of a great number of radioactive gases which are released from great number of rock clefts just before major earthquakes. Enhanced emission of radon radioactive decay will produce an anomalously large number of ion pairs. The positive particles will be transported downward by the fair weather electrostatic field and pile up near the surface. Finally, obviously and abnormally, an oriented upward atmospheric electric field Ez near the ground could be formed. Therefore, monitoring this Ez may be applied effectively in earthquake warning.

Published
2020

7. Selectively driving cholinergic fibers optically in the thalamic reticular nucleus promotes sleep.

Author

Ni, K-M, Hou, X-J, Yang, C-H, Dong, P, Li, Y, Zhang, Y, Jiang, P, Berg, DK, Duan, S, and Li, X-M

Subjects
Thalamic Nuclei, Cholinergic Fibers, Animals, Mice, Transgenic, Photic Stimulation, Arousal, Sleep, GABAergic Neurons
Abstract

Cholinergic projections from the basal forebrain and brainstem are thought to play important roles in rapid eye movement (REM) sleep and arousal. Using transgenic mice in which channelrhdopsin-2 is selectively expressed in cholinergic neurons, we show that optical stimulation of cholinergic inputs to the thalamic reticular nucleus (TRN) activates local GABAergic neurons to promote sleep and protect non-rapid eye movement (NREM) sleep. It does not affect REM sleep. Instead, direct activation of cholinergic input to the TRN shortens the time to sleep onset and generates spindle oscillations that correlate with NREM sleep. It does so by evoking excitatory postsynaptic currents via α7-containing nicotinic acetylcholine receptors and inducing bursts of action potentials in local GABAergic neurons. These findings stand in sharp contrast to previous reports of cholinergic activity driving arousal. Our results provide new insight into the mechanisms controlling sleep.

Published
2016

10. Limit cycle theory of temporal current self-oscillations in sequential tunneling of superlattices

Author

Wang, X. R., Sun, Z. Z., Duan, S. Q., and Wang, Shi-dong

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

A unified theory of the temporal current self-oscillations is presented. We establish these oscillations as the manifestations of limit cycles, around unstable steady-state solutions caused by the negative differential conductance. This theory implies that both the generation and the motion of an electric-field domain boundary are universal in the sense that they do not depend on the initial conditions. Under an extra weak ac bias with a frequency $\omega_{ac}$, the frequency must be either $\omega_{ac}$ or an integer fractional of $\omega_{ac}$ if the tunneling current oscillates periodically in time, indicating the periodic doubling for this non-linear dynamical system, Comment: 4 pages and 5 figures; v2: presentation improvement

Published
2002

11. Expenditures for the care of HIV-infected patients in rural areas in China's antiretroviral therapy programs

Author

Zhou, F, Kominski, GF, Qian, HZ, Wang, J, Duan, S, Guo, Z, and Zhao, X

Abstract

Background: The Chinese government has provided health services to those infected by the human immunodeficiency virus (HIV) under the acquired immunodeficiency syndrome (AIDS) care policy since 2003. Detailed research on the actual expenditures and costs for providing care to patients with AIDS is needed for future financial planning of AIDS health care services and possible reform of HIV/AIDS-related policy. The purpose of the current study was to determine the actual expenditures and factors influencing costs for untreated AIDS patients in a rural area of China after initiating highly active antiretroviral therapy (HAART) under the national Free Care Program (China CARES).Methods: A retrospective cohort study was conducted in Yunnan and Shanxi Provinces, where HAART and all medical care are provided free to HIV-positive patients. Health expenditures and costs in the first treatment year were collected from medical records and prescriptions at local hospitals between January and June 2007. Multivariate linear regression was used to determine the factors associated with the actual expenditures in the first antiretroviral (ARV) treatment year.Results: Five ARV regimens are commonly used in China CARES: zidovudine (AZT) + lamivudine (3TC) + nevirapine (NVP), stavudine (D4T) + 3TC + efavirenz (EFV), D4T + 3TC + NVP, didanosine (DDI) + 3TC + NVP and combivir + EFV. The mean annual expenditure per person for ARV medications was US$2,242 (US$1 = 7 Chinese Yuan (CNY)) among 276 participants. The total costs for treating all adverse drug events (ADEs) and opportunistic infections (OIs) were US$29,703 and US$23,031, respectively. The expenses for treatment of peripheral neuritis and cytomegalovirus (CMV) infections were the highest among those patients with ADEs and OIs, respectively. On the basis of multivariate linear regression, CD4 cell counts (100-199 cells/μL versus

Published
2011

13. RNA-seq analysis of the peduncle development of Rht12dwarf plants and primary mapping of Rht12in common wheat

Author

Chen, L., Yang, Y., Mishina, K., Cui, C., Zhao, Z., Duan, S., Chai, Y., Su, R., Chen, F., and Hu, Y. G.

Abstract

Rht12, a dominant dwarfing gene that reduces plant height by approximately 40.0% and substantially decreases peduncle development by 45.0%, has been suggested as an alternative dwarfing gene for wheat improvement. However, the mechanism of dwarf caused by Rht12is unclear and efficient molecular markers of Rht12is also lacking in breeding. To explore candidate genes involved in peduncle elongation and to construct a genetic map of Rht12, RNA-seq analysis was applied using the peduncle samples at heading stages of the tall and dwarf residual heterozygous lines derived from the cross of Ningchun45 (rht12rht12) and Karcagi12 (Rht12Rht12). Differentially expressed genes were screened and annotated, genes involved in polyamine oxidation, carotenoid biosynthesis, protein ubiquitination process and ascorbate pathway were found to be associated with peduncle elongation. Moreover, ten KASP markers on chromosome 5AL closely linked with Rht12were developed using the SNPs from the RNA-seq data with an F2mapping population. Furthermore, these markers were mapped to the wheat genome sequence and Rht12was predicted within the region of 673.7–689.9 Mb on chromosome 5AL. These results provide a better understanding of the molecular mechanisms underlying the development of the peduncle and other stems in wheat, especially in Rht12dwarf plants, and also promote fine mapping of Rht12.

Published
2024
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35. Imaging-anatomic Measurements of Carotid Artery Bifurcation.

Author

Duan, S., Li, J., CHI, J., Yang, L., Lv, S., and Huang, Y.

Abstract

Objective: To have anatomic measurements of carotid artery bifurcation (CAB) with 64-spiral computed tomography angiography (64-SCTA), and provide anatomic basis for related research. Methods: Imaging data of 92 subjects (45 males, 47 females, the age range 20-82 years and mean age 48.4 ± 6.1 years) without pathology of CAB, who underwent 64-SCTA in head and neck from June 1, 2008 to June 30, 2010, were selected from the Picture Archiving and Communication Systems in Zhongshan Hospital of Xiamen University, Fujian, China. On the 3D images, the angle and size of CAB were measured, and the statistical comparisons of measurements were made between the bilateral, sex and age groups. Results: The measurements of CAB were divided into young (= 40 years) and older (> 40 years) groups: bifurcation angle is 36.206° ± 10.210° and 49.343° ± 16.489°, respectively; the inner diameter of common carotid artery (CCA) is 6.820 ± 0.635 and 6.845 ± 0.838 mm, respectively; the proximal inner diameter of internal carotid artery (ICA) is 7.143 ± 0.992 and 7.476 ± 1.630 mm, of the enlargement is 7.568 ± 1.069 and 8.554 ± 1.733 mm, of the distal is 4.897 ± 0.508 and 5.123 ± 0.699 mm, respectively; the inner diameter of external carotid artery (ECA) is 4.324 ± 0.580 and 4.104 ± 0.638 mm, respectively. There were statistically significant differences in all the measurements between male and female groups, in the bifurcation angle, inner diameters of ICA and ECA between young and older groups, and in the bifurcation angle between the left and right (p < 0.05). Conclusion: A 64-SCTA with 3D image post-processing technique can clearly observe and show the CAB. All CAB measurements will provide the objective basis for applied anatomy, imaging diagnosis and surgery treatment. [ABSTRACT FROM AUTHOR]

Published
2021
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37. Quantitative analysis of a Hall system in the exhaust of asymmetric magnetic reconnection

Author

Zhang, Y. C., primary, Lavraud, B., additional, Dai, L., additional, Wang, C., additional, Marchaudon, A., additional, Avanov, L., additional, Burch, J., additional, Chandler, M., additional, Dorelli, J., additional, Duan, S. P., additional, Ergun, R. E., additional, Gershman, D. J., additional, Giles, B., additional, Khotyaintsev, Y. V., additional, Lindqvist, P. A., additional, Paterson, W., additional, Russell, C. T., additional, Schiff, C., additional, Tang, B. B., additional, and Torbert, R., additional

Published
2017
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38. Quantitative analysis of a Hall system in the exhaust of asymmetric magnetic reconnection

Author

Zhang, Y. C., Lavraud, B., Dai, L., Wang, C., Marchaudon, A., Avanov, L., Burch, J., Chandler, M., Dorelli, J., Duan, S. P., Ergun, R. E., Gershman, D. J., Giles, B., Khotyaintsev, Y. V., Lindqvist, Per-Arne, Paterson, W., Russell, C. T., Schiff, C., Tang, B. B., Torbert, R., Zhang, Y. C., Lavraud, B., Dai, L., Wang, C., Marchaudon, A., Avanov, L., Burch, J., Chandler, M., Dorelli, J., Duan, S. P., Ergun, R. E., Gershman, D. J., Giles, B., Khotyaintsev, Y. V., Lindqvist, Per-Arne, Paterson, W., Russell, C. T., Schiff, C., Tang, B. B., and Torbert, R.

Abstract

Taking advantage of high-resolution measurements from the MMS mission, we find evidence for a complete Hall system in the exhaust of asymmetric magnetic reconnection 40 Di downstream of the X line. The investigation of the fine structure of the Hall system reveals that it displays features in the exhaust similar to those reported previously in the ion diffusion region by simulations and observations. This finding confirms the importance of particle-scale processes in the reconnection exhaust as well. On the magnetospheric side of the exhaust, electrons are strongly accelerated by parallel electric fields. This process significantly contributes to feed the Hall current system, resulting in a nonnegligible Hall magnetic field signature on this side despite an otherwise lower density. Calculation of the induced out-of-plane magnetic field by in-plane currents (based on Biot-Savart law) provides direct quantitative evidence for the process of Hall magnetic field generation by the Hall current system. A strong normal Hall electric field is present only on the magnetospheric side of the exhaust region, consistent with previous works. Multipoint data analysis shows that the ion pressure gradient in the ion momentum equation produces this Hall electric field. This global pattern of the Hall system can be explained by kinetic Alfvén wave theory., Funding details: 41231066, NSFC, National Natural Science Foundation of China; Funding details: 41574159, NSFC, National Natural Science Foundation of China; Funding details: 41574161, NSFC, National Natural Science Foundation of China; Funding details: 41574163, NSFC, National Natural Science Foundation of China; Funding text: MMS data can be accessed at https://lasp.colorado.edu/mms/sdc/public/. We acknowledge all the MMS teams for their wonderful work. This work was supported by the National Natural Science Foundation of China (grants 41574163, 41574159, 41574161 and 41231066) and the Specialized Research Fund for State Key Laboratories. Work on MMS at IRAP is supported by CNRS and CNES.QC 20171201

Published
2017
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44. A manganese distribution prediction model for CaO–SiO2–FeO–MgO–MnO–Al2O3slags based on IMCT

Author

Duan, S. C., Guo, X. L., Guo, H. J., and Guo, J.

Abstract

A thermodynamic model for predicting manganese distribution ratio LMnand manganese capacity CMnof CaO–SiO2–FeO–MgO–MnO–Al2O3slags, i.e. IMCT-LMnand IMCT-CMnmodels, has been developed by using a thermodynamic model for calculating mass action concentration of ion couples or structural units in the slags based on the ion–molecule coexistence theory (IMCT). The developed IMCT-LMnand IMCT-CMnmodels have been verified with the experiment results of CaO–SiO2–FeO–MgO–MnO–Al2O3, CaO–SiO2–MgO–FeO–Fe2O3–MnO–P2O5, CaO–SiO2–MgO–FeO–Fe2O3–MnO–Al2O3–P2O5slags reported by different researchers, a total of 200 industrial measurements with large compositional variations and predicted results by summarised five LMnmodels and two CMnmodels. The developed thermodynamic model for calculating manganese distribution ratio can determine quantitatively the respective manganese distribution ratio LMn,iand the respective manganese capacity CMn,iof four demanganisation products as MnO, , and . A significant difference of demanganisation abilities among FeO, FeO + Al2O3and FeO + SiO2can be found as 98, 1.8 and 0.2%. By comparing binary and complex basicity, the optical basicity is recommended to describe the relationship between basicity and manganese distribution ratio. With the aid of the current model, the co-effects of the ratio and optical basicity on the LMnand CMnof CaO–SiO2–FeO–MgO–MnO–Al2O3slags are investigated.

Published
2017
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45. Numerical disintegration of water sensitive rock: case study of mudrock.

Author

Jiang, Q., Hao, X. J., Duan, S. Q., and Jiang, Y.

Abstract

Water sensitive rock is harmful for the stability of geotechnical engineering due to its obviously disintegrating property. In this paper, the disintegration characters of the mudrock had been detected firstly by the X-ray computerized tomographic scanner. The visual observation indicated that the disintegrating mechanism of this material under water environment is that the microfractures firstly provide the initial path for the water to seep into the unloaded mudrock, then the seeped water would induce the swelling of clay minerals and ion solution of carbonate. As a result, cracks would appear and extend due to the damage of the mudrock's integrity. In addition, a numerical model was also developed to describe the disintegrating process of mudrock. [ABSTRACT FROM AUTHOR]

Published
2014
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46. Experimental Study on the Atlanto-axial Joint and Related Structures with Regional Anatomy and Medical Imaging.

Author

S. Lv., He, H., Yang, L., Lin, Q., and Duan, S.

Abstract

Copyright of West Indian Medical Journal is the property of West Indian Medical Journal (WIMJ) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2011

47. Investigation of a multi objective optimization tool for engine calibration.

Author

Wu, M. H., Lin, W., and Duan, S. Y.

Subjects
COMBINATORIAL optimization, STANDARDIZATION, CALIBRATION, AUTOMOBILE industry, MATHEMATICAL optimization, ENERGY consumption, ROTATIONAL motion (Rigid dynamics), HYDRAULIC torque converters, POWER resources
Abstract

Since multi objective optimizations are becoming more important in engine calibration, the paper investigates multi objective genetic algorithms in the application of engine optimization. Although several multi objective genetic algorithms have been developed and some have been applied successfully in the automotive industry, it is difficult to determine which multi objective genetic algorithm outperforms others in finding the set of optimal solutions or Pareto optimal front in a practical multi objective optimization problem. Based on some widely used multi objective genetic algorithms, the paper proposes a combined scheme to deal with the difficulties in finding the optimal solution set during the engine calibration process. In the proposed approach the real coded representation is employed in the genetic algorithm and the elitist strategy is applied for each multi objective genetic algorithm used. To assess the proposed approach, two computational examples are given to minimize the brake specific fuel consumption and to maximize the output power torque simultaneously. The results show that the proposed approach is well suited to multi objective optimization in engine calibration. [ABSTRACT FROM AUTHOR]

Published
2008
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48. Engine test data modelling by evolutionary radial basis function networks.

Author

Lin, W, Wu, M H, and Duan, S

Subjects
ENGINES, TESTING, MODELING (Sculpture), GENETIC algorithms, RADIAL basis functions
Abstract

The engine test bed is introduced briefly and the importance of modelling for the engine test is discussed. The application of combining radial basis function (RBF ) networks and a realcoded genetic algorithm (RCGA) to create the model is described for the engine test. Finally, the experimental results are analysed and it is shown that the proposed approach combining RCGA and RBF models is well suited for the engine test data modelling task. [ABSTRACT FROM AUTHOR]

Published
2003
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49. Modulation of Ascorbic Acid-Induced DNA Cleavage by Polyamide: Cleavage Manner, Kinetics and Mechanism

Author

Li, C., Duan, S., Xu, J., Qiao, R., Xu, P., and Zhao, Y.

Abstract

Manipulation of DNA presents a great interest in biotechnology and therapeutics. The molecules that damage DNA selectively offer new prospects for controlled manipulation of DNA. The conjugations of DNA-code reading molecules such as polyamides to reagents that induce DNA damages provide an approach to reach this goal. In this work, a new compound which contained polyamide and ascorbic acid conjugated by flexible linker (polyamide-Vc), was successfully synthesized, characterized, and evaluated as DNA cleavage agent, compared with that by using ascorbic acid molecule. The kinetics data showed that polyamide-Vc successfully promoted the cleavage of plasmid DNA, with kmax of 0.314 h-1 and Kd of 0.105 mM. The evaluation of DNA linearization elicited that the activity of cleaving double-strand in the supercoiled pUC18 plasmid DNA by polyamide-Vc was enhanced remarkably, achieving n1/n2 ratio of 13.9 at 1.2 mM for 1 h. The introduction of polyamide to Vc could also partially weaken the inhibition of hydrogen radical to double-strand cleavage process because of its good binding activity to DNA. We anticipate that this work could provide a method for improving the efficiency of double-strand cleavage, especially to oxidative cleavage agents.

Published
2012

50. Synthesis and Evaluation of Hydrolyzable Hyaluronan-Tethered Bupivacaine Delivery Systems

Author

Gianolio, D. A., Philbrook, M., Avila, L. Z., MacGregor, H., Duan, S. X., Bernasconi, R., Slavsky, M., Dethlefsen, S., Jarrett, P. K., and Miller, R. J.

Abstract

Local anesthetics are useful for reducing acute pain, but their short duration precludes them from use in solely managing postoperative pain. To prolong the duration of local anesthesia, we conjugated bupivacaine to native hyaluronan (HA) and divinyl sulfone cross-linked Hylan A (Hylan B particles) using a hydrolyzable linker incorporating an imide. Bupivacaine was prepared for conjugation to HA by forming the acryl imide derivative. Separately, the carboxyl group of HA was reacted with nipsylethylamine (NEA) using carbodiimide-mediated coupling to provide HA-NEA that was subsequently reduced with tris(2-carboxyethylphosphine) hydrochloride to yield HA carrying a free sulfhydryl (HA-SH). The HA−bupivacaine conjugate was assembled by reacting HA-SH with acrylbupivacaine. Characterization of the conjugates showed 22% degree of modification by 1 mol of carboxyl. In vitro release studies comparing bupivacaine admixed in HA with bupivacaine conjugated to HA showed half-lives of 0.4 ± 0.1 h, and 16.9 ± 0.2 h, respectively, and the bupivacaine was released chemically unaltered as confirmed by LC-MS. In vivo studies to assess the duration of anesthetic activity were performed in a rat sciatic nerve blockade model. For these studies, bupivacaine was conjugated to Hylan B following a similar procedure, and the degree of modification obtained was 14%. Free bupivacaine (3 and 16 mg/kg) and free bupivacaine (3 mg/kg) admixed with Hylan B particles showed nerve block over 4, 9, and 6 h, respectively. Free bupivacaine (3 mg/kg) admixed with bupivacaine (13 mg/kg) conjugated to Hylan B particles showed a four to 5-fold longer impairment of motor function over the free bupivacaine formulations with a total block time of 19 h. Bupivacaine conjugated to Hylan B particles has the potential to prolong the duration of local anesthesia.

Published
2005

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