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1. Extragalactic fast X-ray transient from a weak relativistic jet associated with a Type Ic-BL supernova

Author

Sun, H., Li, W. -X., Liu, L. -D., Gao, H., Wang, X. -F., Yuan, W., Zhang, B., Filippenko, A. V., Xu, D., An, T., Ai, S., Brink, T. G., Liu, Y., Liu, Y. -Q., Wang, C. -Y., Wu, Q. -Y., Wu, X. -F., Yang, Y., Zhang, B. -B., Zheng, W. -K., Ahumada, T., Dai, Z. -G., Delaunay, J., Elias-Rosa, N., Benetti, S., Fu, S. -Y., Howell, D. A., Huang, Y. -F., Kasliwal, M. M., Karambelkar, V., Stein, R., Lei, W. -H., Lian, T. -Y., Peng, Z. -K., Ridnaia, A. V., Svinkin, D. S., Wang, X. -Y., Wang, A. -L., Wei, D. -M., An, J., Andrews, M., Bai, J. -M, Dai, C. -Y., Ehgamberdiev, S. A., Fan, Z., Farah, J., Feng, H. -C., Fynbo, J. P. U., Guo, W. -J., Guo, Z., Hu, M. -K., Hu, J. -W., Jiang, S. -Q., Jin, J. -J., Li, A., Li, J. -D., Li, R. -Z., Liang, Y. -F., Ling, Z. -X., Liu, X., Mao, J. -R., McCully, C., Mirzaqulov, D., Newsome, M., Gonzalez, E. Padilla, Pan, X., Terreran, G., Tinyanont, S., Wang, B. -T., Wang, L. -Z., Wen, X. -D., Xiang, D. -F., Xue, S. -J., Yang, J., Zhu, Z. -P., Cai, Z. -M., Castro-Tirado, A. J., Chen, F. -S., Chen, H. -L., Chen, T. -X., Chen, W., Chen, Y. -H., Chen, Y. -F., Chen, Y., Cheng, H. -Q., Cordier, B., Cui, C. -Z., Cui, W. -W., Dai, Y. -F., Fan, D. -W., Feng, H., Guan, J., Han, D. -W., Hou, D. -J., Hu, H. -B., Huang, M. -H., Huo, J., Jia, S. -M., Jia, Z. -Q., Jiang, B. -W., Jin, C. -C., Jin, G., Kuulkers, E., Li, C. -K., Li, D. -Y., Li, J. -F., Li, L. -H., Li, M. -S., Li, W., Li, Z. -D., Liu, C. -Z, Liu, H. -Y., Liu, H. -Q., Liu, M. -J., Lu, F. -J., Luo, L. -D., Ma, J., Mao, X., Nandra, K., O'Brien, P., Pan, H. -W., Rau, A., Rea, N., Sanders, J., Song, L. -M., Sun, S. -L., Sun, X. -J., Tan, Y. -Y., Tang, Q. -J., Tao, Y. -H., Wang, H., Wang, J., Wang, L., Wang, W. -X., Wang, Y. -L., Wang, Y. -S., Xiong, D. -R., Xu, H. -T., Xu, J. -J., Xu, X. -P., Xu, Y. -F., Xu, Z., Xue, C. -B., Xue, Y. -L., Yan, A. -L., Yang, H. -N., Yang, X. -T., Yang, Y. -J., Zhang, C., Zhang, J., Zhang, M., Zhang, S. -N., Zhang, W. -D., Zhang, W. -J., Zhang, Y. -H., Zhang, Z., Zhang, Z. -L., Zhao, D. -H., Zhao, H. -S., Zhao, X. -F., Zhao, Z. -J., Zhou, Y. -L., Zhu, Y. -X., and Zhu, Z. -C.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Massive stars end their life as core-collapse supernovae, amongst which some extremes are Type Ic broad-lined supernovae associated with long-duration gamma-ray bursts (LGRBs) having powerful relativistic jets. Their less-extreme brethren make unsuccessful jets that are choked inside the stars, appearing as X-ray flashes or low-luminosity GRBs. On the other hand, there exists a population of extragalactic fast X-ray transients (EFXTs) with timescales ranging from seconds to thousands of seconds, whose origins remain obscure. Known sources that contribute to the observed EFXT population include the softer analogs of LGRBs, shock breakouts of supernovae, or unsuccessful jets. Here, we report the discovery of the bright X-ray transient EP240414a detected by the Einstein Probe (EP), which is associated with the Type Ic supernova SN 2024gsa at a redshift of 0.401. The X-ray emission evolution is characterised by a very soft energy spectrum peaking at < 1.3 keV, which makes it distinct from known LGRBs, X-ray flashes, or low-luminosity GRBs. Follow-up observations at optical and radio bands revealed the existence of a weak relativistic jet that interacts with an extended shell surrounding the progenitor star. Located on the outskirts of a massive galaxy, this event reveals a new population of explosions of Wolf-Rayet stars characterised by a less powerful engine that drives a successful but weak jet, possibly owing to a progenitor star with a smaller core angular momentum than in traditional LGRB progenitors., Comment: 43 pages, 9 figures, 4 tables, submitted. Comments are welcome

Published
2024

2. Soft X-ray prompt emission from a high-redshift gamma-ray burst EP240315a

Author

Liu, Y., Sun, H., Xu, D., Svinkin, D. S., Delaunay, J., Tanvir, N. R., Gao, H., Zhang, C., Chen, Y., Wu, X. -F., Zhang, B., Yuan, W., An, J., Bruni, G., Frederiks, D. D., Ghirlanda, G., Hu, J. -W., Li, A., Li, C. -K., Li, J. -D., Malesani, D. B., Piro, L., Raman, G., Ricci, R., Troja, E., Vergani, S. D., Wu, Q. -Y., Yang, J., Zhang, B. -B., Zhu, Z. -P., Postigo, A. de Ugarte, Demin, A. G., Dobie, D., Fan, Z., Fu, S. -Y., Fynbo, J. P. U., Geng, J. -J., Gianfagna, G., Hu, Y. -D., Huang, Y. -F., Jiang, S. -Q., Jonker, P. G., Julakanti, Y., Kennea, J. A., Kokomov, A. A., Kuulkers, E., Lei, W. -H., Leung, J. K., Levan, A. J., Li, D. -Y., Li, Y., Littlefair, S. P., Liu, X., Lysenko, A. L., Ma, Y. -N., Martin-Carrillo, A., O'Brien, P., Parsotan, T., Quirola-Vasquez, J., Ridnaia, A. V., Ronchini, S., Rossi, A., Mata-Sanchez, D., Schneider, B., Shen, R. -F., Thakur, A. L., Tohuvavohu, A., Torres, M. A. P., Tsvetkova, A. E., Ulanov, M. V., Wei, J. -J., Xiao, D., Yin, Y. -H. I., Bai, M., Burwitz, V., Cai, Z. -M., Chen, F. -S., Chen, H. -L., Chen, T. -X., Chen, W., Chen, Y. -F., Chen, Y. -H., Cheng, H. -Q., Cui, C. -Z., Cui, W. -W., Dai, Y. -F., Dai, Z. -G., Eder, J., Fan, D. -W., Feldman, C., Feng, H., Feng, Z., Friedrich, P., Gao, X., Guan, J., Han, D. -W, Han, J., Hou, D. -J., Hu, H. -B., Hu, T., Huang, M. -H., Huo, J., Hutchinson, I., Ji, Z., Jia, S. -M., Jia, Z. -Q., Jiang, B. -W., Jin, C. -C., Jin, G., Jin, J. -J., Keereman, A., Lerman, H., Li, J. -F., Li, L. -H., Li, M. -S., Li, W., Li, Z. -D., Lian, T. -Y., Liang, E. -W., Ling, Z. -X., Liu, C. -Z., Liu, H. -Y., Liu, H. -Q., Liu, M. -J., Liu, Y. -R., Lu, F. -J., LU, H. -J., Luo, L. -D., Ma, F. L., Ma, J., Mao, J. -R., Mao, X., McHugh, M., Meidinger, N., Nandra, K., Osborne, J. P., Pan, H. -W., Pan, X., Ravasio, M. E., Rau, A., Rea, N., Rehman, U., Sanders, J., Santovincenzo, A., Song, L. -M., Su, J., Sun, L. -J., Sun, S. -L., Sun, X. -J., Tan, Y. -Y., Tang, Q. -J., Tao, Y. -H., Tong, J. -Z., Wang, H., Wang, J., Wang, L., Wang, W. -X., Wang, X. -F., Wang, X. -Y., Wang, Y. -L., Wang, Y. -S., Wei, D. -M., Willingale, R., Xiong, S. -L., Xu, H. -T., Xu, J. -J., Xu, X. -P., Xu, Y. -F., Xu, Z., Xue, C. -B., Xue, Y. -L., Yan, A. -L., Yang, F., Yang, H. -N., Yang, X. -T., Yang, Y. -J, Yu, Y. -W., Zhang, J., Zhang, M., Zhang, S. -N., Zhang, W. -D., Zhang, W. -J., Zhang, Y. -H., Zhang, Z., Zhang, Z. -L., Zhao, D. -H., Zhao, H. -S., Zhao, X. -F., Zhao, Z. -J., Zhou, L. -X., Zhou, Y. -L., Zhu, Y. -X., Zhu, Z. -C., and Zuo, X. -X.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Long gamma-ray bursts (GRBs) are believed to originate from core collapse of massive stars. High-redshift GRBs can probe the star formation and reionization history of the early universe, but their detection remains rare. Here we report the detection of a GRB triggered in the 0.5--4 keV band by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated as EP240315a, whose bright peak was also detected by the Swift Burst Alert Telescope and Konus-Wind through off-line analyses. At a redshift of $z=4.859$, EP240315a showed a much longer and more complicated light curve in the soft X-ray band than in gamma-rays. Benefiting from a large field-of-view ($\sim$3600 deg$^2$) and a high sensitivity, EP-WXT captured the earlier engine activation and extended late engine activity through a continuous detection. With a peak X-ray flux at the faint end of previously known high-$z$ GRBs, the detection of EP240315a demonstrates the great potential for EP to study the early universe via GRBs., Comment: 41 pages, 8 figures, 7 tables

Published
2024

3. The Lobster Eye Imager for Astronomy Onboard the SATech-01 Satellite

Author

Ling, Z. X., Sun, X. J., Zhang, C., Sun, S. L., Jin, G., Zhang, S. N., Zhang, X. F., Chang, J. B., Chen, F. S., Chen, Y. F., Cheng, Z. W., Fu, W., Han, Y. X., Li, H., Li, J. F., Li, Y., Li, Z. D., Liu, P. R., Lv, Y. H., Ma, X. H., Tang, Y. J., Wang, C. B., Xie, R. J., Xue, Y. L., Yan, A. L., Zhang, Q., Bao, C. Y., Cai, H. B., Cheng, H. Q., Cui, C. Z., Dai, Y. F., Fan, D. W., Hu, H. B., Hu, J. W., Huang, M. H., Jia, Z. Q., Jin, C. C., Li, D. Y., Li, J. Q., Liu, H. Y., Liu, M. J., Liu, Y., Pan, H. W., Qiu, Y. L., Sugizaki, M., Sun, H., Wang, W. X., Wang, Y. L., Wu, Q. Y., Xu, X. P., Xu, Y. F., Yang, H. N., Yang, X., Zhang, B., Zhang, M., Zhang, W. D., Zhang, Z., Zhao, D. H., Cong, X. Q., Jiang, B. W., Li, L. H., Qiu, X. B., Sun, J. N., Su, D. T., Wang, J., Wu, C., Xu, Z., Yang, X. M., Zhang, S. K., Zhang, N., Zhu, Y. F., Ban, H. Y., Bi, X. Z., Cai, Z. M., Chen, W., Chen, X., Chen, Y. H., Cui, Y., Duan, X. L., Feng, Z. G, Gao, Y., He, J. W., He, T., Huang, J. J., Li, F., Li, J. S., Li, T. J., Li, T. T., Liu, H. Q., Liu, L., Liu, R., Liu, S., Meng, N., Shi, Q., Sun, A. T., Wang, Y. M., Wang, Y. B., Wu, H. C., Xu, D. X, Yang, Y. Q, Yang, Y., Yu, X. S., Zhang, K. X., Zhang, Y. L., Zhang, Y. H., Zhang, Y. T., Zhou, H., Zhu, X. C., Cheng, J. S., Qin, L., Wang, L., Wang, Q. L., Bai, M., Gao, R. L., Ji, Z., Liu, Y. R., Ma, F. L., Shi, Y. J., Su, J., Tan, Y. Y., Tong, J. Z., Xu, H. T., Xue, C. B., Xue, G. F., and Yuan, W.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The Lobster Eye Imager for Astronomy (LEIA), a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe (EP) mission, was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on 27 July 2022. In this paper, we introduce the design and on-ground test results of the LEIA instrument. Using state-of-the-art Micro-Pore Optics (MPO), a wide field-of-view (FoV) of 346 square degrees (18.6 degrees * 18.6 degrees) of the X-ray imager is realized. An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons, and four large-format complementary metal-oxide semiconductor (CMOS) sensors, each of 6 cm * 6 cm, are used as the focal plane detectors. The instrument has an angular resolution of 4 - 8 arcmin (in FWHM) for the central focal spot of the point spread function, and an effective area of 2 - 3 cm2 at 1 keV in essentially all the directions within the field of view. The detection passband is 0.5 - 4 keV in the soft X-rays and the sensitivity is 2 - 3 * 10-11 erg s-1 cm-2 (about 1 mini-Crab) at 1,000 second observation. The total weight of LEIA is 56 kg and the power is 85 W. The satellite, with a design lifetime of 2 years, operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes. LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation, and by optimizing the working setups of the instrumental parameters. In addition, LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band, albeit limited useful observing time available., Comment: Accepted by RAA

Published
2023
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4. First wide field-of-view X-ray observations by a lobster eye focusing telescope in orbit

Author

Zhang, C., Ling, Z. X., Sun, X. J., Sun, S. L., Liu, Y., Li, Z. D., Xue, Y. L., Chen, Y. F., Dai, Y. F., Jia, Z. Q., Liu, H. Y., Zhang, X. F., Zhang, Y. H., Zhang, S. N., Chen, F. S., Cheng, Z. W., Fu, W., Han, Y. X., Li, H., Li, J. F., Li, Y., Liu, P. R., Ma, X. H., Tang, Y. J., Wang, C. B., Xie, R. J., Yan, A. L., Zhang, Q., Jiang, B. W., Jin, G., Li, L. H., Qiu, X. B., Su, D. T., Sun, J. N., Xu, Z., Zhang, S. K., Zhang, Z., Zhang, N., Bi, X. Z., Cai, Z. M., He, J. W., Liu, H. Q., Zhu, X. C., Cheng, H. Q., Cui, C. Z., Fan, D. W., Hu, H. B., Huang, M. H., Jin, C. C., Li, D. Y., Pan, H. W., Wang, W. X., Xu, Y. F., Yang, X., Zhang, B., Zhang, M., Zhang, W. D., Zhao, D. H., Bai, M., Ji, Z., Liu, Y. R., Ma, F. L., Su, J., Tong, J. Z., Wang, Y. S., Zhao, Z. J., Feldman, C., O'Brien, P., Osborne, J. P., Willingale, R., Burwitz, V., Hartner, G., Langmeier, A., Müller, T., Rukdee, S., Schmidt, T., Kuulkers, E., and Yuan, W.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

As a novel X-ray focusing technology, lobster eye micro-pore optics (MPO) feature both a wide observing field of view and true imaging capability, promising sky monitoring with significantly improved sensitivity and spatial resolution in soft X-rays. Since first proposed by Angel (1979), the optics have been extensively studied, developed and trialed over the past decades. In this Letter, we report on the first-light results from a flight experiment of the Lobster Eye Imager for Astronomy ($LEIA$), a pathfinder of the wide-field X-ray telescope of the Einstein Probe mission. The piggyback imager, launched in July 2022, has a mostly un-vignetted field of view of $18.6^\circ \times 18.6^\circ $. Its spatial resolution is in the range of 4$-$7 arcmin in FWHM and the focal spot effective area is 2$-$3 cm$^2$, both showing only mild fluctuations across the field of view. We present images of the Galactic center region, Sco X-1 and the diffuse Cygnus Loop nebular taken in snapshot observations over 0.5$-$4 keV. These are truly wide-field X-ray images of celestial bodies observed, for the first time, by a focusing imaging telescope. Initial analyses of the in-flight data show excellent agreement between the observed images and the on-ground calibration and simulations. The instrument and its characterization are briefly described, as well as the flight experiment. The results provide a solid basis for the development of the present and proposed wide-field X-ray missions using lobster eye MPO., Comment: 11 pages, 4 figures. Accepted for publication in Astrophysical Journal Letter

Published
2022
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5. First Wide Field-of-view X-Ray Observations by a Lobster-eye Focusing Telescope in Orbit

Author

Zhang, C., primary, Ling, Z. X., additional, Sun, X. J., additional, Sun, S. L., additional, Liu, Y., additional, Li, Z. D., additional, Xue, Y. L., additional, Chen, Y. F., additional, Dai, Y. F., additional, Jia, Z. Q., additional, Liu, H. Y., additional, Zhang, X. F., additional, Zhang, Y. H., additional, Zhang, S. N., additional, Chen, F. S., additional, Cheng, Z. W., additional, Fu, W., additional, Han, Y. X., additional, Li, H., additional, Li, J. F., additional, Li, Y., additional, Liu, P. R., additional, Ma, X. H., additional, Tang, Y. J., additional, Wang, C. B., additional, Xie, R. J., additional, Yan, A. L., additional, Zhang, Q., additional, Jiang, B. W., additional, Jin, G., additional, Li, L. H., additional, Qiu, X. B., additional, Su, D. T., additional, Sun, J. N., additional, Xu, Z., additional, Zhang, S. K., additional, Zhang, Z., additional, Zhang, N., additional, Bi, X. Z., additional, Cai, Z. M., additional, He, J. W., additional, Liu, H. Q., additional, Zhu, X. C., additional, Cheng, H. Q., additional, Cui, C. Z., additional, Fan, D. W., additional, Hu, H. B., additional, Huang, M. H., additional, Jin, C. C., additional, Li, D. Y., additional, Pan, H. W., additional, Wang, W. X., additional, Xu, Y. F., additional, Yang, X., additional, Zhang, B., additional, Zhang, M., additional, Zhang, W. D., additional, Zhao, D. H., additional, Bai, M., additional, Ji, Z., additional, Liu, Y. R., additional, Ma, F. L., additional, Su, J., additional, Tong, J. Z., additional, Wang, Y. S., additional, Zhao, Z. J., additional, Feldman, C., additional, O’Brien, P., additional, Osborne, J. P., additional, Willingale, R., additional, Burwitz, V., additional, Hartner, G., additional, Langmeier, A., additional, Müller, T., additional, Rukdee, S., additional, Schmidt, T., additional, Kuulkers, E., additional, and Yuan, W., additional

Published
2022
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9. Functional integrity of honeybee (Apis mellifera L.) resistant to dieldrin γ‐aminobutyric acid receptor channels conjugated with three fluorescent proteins.

Author

Huang, Q.‐T., Sheng, C.‐W., Jiang, J., Jia, Z.‐Q., Han, Z.‐J., Zhao, C.‐Q., and Liu, G.‐Y.

Subjects
FLUORESCENT proteins, HONEYBEES, GABA receptors, GREEN fluorescent protein, CONFOCAL fluorescence microscopy, DIELDRIN
Abstract

To generate an efficient tool used in Xenopus oocyte expression for in situ investigation of channel receptor expression, distribution and function, the C‐terminus of the honeybee (Apis mellifera L.) resistant to dieldrin (RDL) subunit was fused with *FP, including monomeric red, enhanced yellow or enhanced green fluorescent protein (referred to as mRFP, EYFP and EGFP, respectively). In the present study, all fused *FP‐AmRDLs could be visualized using fluorescence and laser confocal microscopy in cRNA‐injected oocytes. Fluorescence was distributed isotropically in the cellular membrane. The potencies of the agonist γ‐aminobutyric acid (GABA), but not β‐alanine, and the test antagonists (fipronil, flufiprole, dieldrin, α‐endosulfan, bifenazate and avermectin B1a) in the *FP‐AmRDL receptor did not significantly differ from that of the untagged receptor with two‐electrode voltage clamp detection. The half maximal effective concentrations (EC50s) of GABA in AmRDL, EGFP‐AmRDL, EYFP‐AmRDL and mRFP‐AmRDL receptors were 11.98, 12.61, 18.92 and 22.11 μM, respectively, and those of β‐alanine were 651.6, 629.6, 1643.0 and 2146.0 μM, respectively. Inhibition percentages of test antagonists against *FP‐AmRDL and AmRDL were not significantly different from each other. Overall, the consistency in functional properties between *FP‐AmRDL and AmRDL receptors makes pGH19‐*FP a promising tool for further in situ investigation of GABA receptors. [ABSTRACT FROM AUTHOR]

Published
2019
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11. Dehydroepiandrosterone protects vascular endothelial cells against apoptosis through a G alpha(i) protein-dependent activation of phosphatidylinositol 3-kinase/Akt and regulation of antiapoptotic Bcl-2 expression

Author

Liu, D. M., Si, H. W., Reynolds, K. A., Zhen, W., Jia, Z. Q., Dillon, J. S., Biomedical Sciences and Pathobiology, and Human Nutrition, Foods, and Exercise

Subjects
estrogen-receptor, smooth-muscle-cells, nongenomic mechanisms, nitric-oxide synthase, kinase, akt, proliferation, nf-kappa-b, endocrinology & metabolism, atherosclerosis, in-vivo, hormones, hormone substitutes, and hormone antagonists
Abstract

The adrenal steroid dehydroepiandrosterone (DHEA) may improve vascular function, but the mechanism is unclear. In the present study, we show that DHEA significantly increased cell viability, reduced caspase-3 activity, and protected both bovine and human vascular endothelial cells against serum deprivation-induced apoptosis. This effect was dose dependent and maximal at physiological concentrations (0.1-10 nM). DHEA stimulation of bovine aortic endothelial cells resulted in rapid and dose-dependent phosphorylation of Akt, which was blocked by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), the upstream kinase of Akt. Accordingly, inhibition of PI3K or transfection of the cells with dominant-negative Akt ablated the antiapoptotic effect of DHEA. The induced Akt phosphorylation and subsequent cytoprotective effect of DHEA were dependent on activation of G alpha(i) proteins, but were estrogen receptor independent, because these effects were blocked by pertussis toxin but not by the estrogen receptor inhibitor ICI182,780 or the aromatase inhibitor aminoglutethimide. Finally, DHEA enhanced antiapoptotic Bcl-2 protein expression, its promoter activity, and gene transcription attributable to the activation of the PI3K/Akt pathway. Neutralization of Bcl-2 by antibody transfection significantly decreased the antiapoptotic effect of DHEA. These findings provide the first evidence that DHEA acts as a survival factor for endothelial cells by triggering the G alpha(i)-PI3K/Akt-Bcl-2 pathway to protect cells against apoptosis. This may represent an important mechanism underlying the vascular protective effect of DHEA. Thomas F. Jeffress and Kate Jeffress Memorial Trust American Heart Association Mid-Atlantic Affiliate Grant 056 0565356U Virginia Tech Office of Research and Development, Department of Veterans Administration American Heart Association Heartland Affiliate grant National Institutes of Health Grant R01AG55741

Published
2007

17. Changes in soil organic carbon and nitrogen capacities of Salix cheilophila Schneid. along a revegetation chronosequence in semi-arid degraded sandy land of the Gonghe Basin, Tibetan Plateau.

Author

Yu, Y. and Jia, Z. Q.

Subjects
*HUMUS, *REVEGETATION, *NITROGEN, *BIOMASS, *SOIL depth, *CARBON cycle
Abstract

The Gonghe Basin is a sandified and desertified region of China, but the distribution of soil organic carbon (SOC) and total nitrogen (TN) along the cultivation chronosequence across this ecologically fragile region is not well understood. This study was carried out to understand the effects of restoration with Salix cheilophila for different periods of time (6, 11, 16, 21 years) to test whether it enhanced C and N storage. Soil samples, in four replications from seven depth increments (0-10, 10-20, 20-30, 30-50, 50-100, 100-150 and 150-200 cm), were collected in each stand. Soil bulk density, SOC, TN, aboveground biomass and root biomass were measured. Results indicated that changes occurred in both the upper and deeper soil layers with an increase in revegetation time. The 0-200 cm soil showed that the 6-year stand gained 3.89MgC ha-1 and 1.00MgNha-1, which accounted for 40.82% of the original SOC and 11.06% of the TN of the 0-year stand. The 11-year stand gained 7.82MgC ha-1 and 1.98MgNha-1 in the 0-200 cm soil layers, accounting for 58.06% of the SOC and 19.80% of the TN of the 0-year stand. The 16- year stand gained 11.32MgC ha-1 and 3.30MgNha-1 in the 0-200 cm soil layers, accounting for 66.71% of the SOC and 21.98% of the TN of the 0-year stand. The 21-year stand gained 13.05MgC ha-1 and 5.45MgNha-1 from the same soil depth, accounting for 69.79%of the SOC and 40.47%of the TN compared with the 0-year stand. The extent of these changes depended on soil depth and plantation age. The results demonstrated that, as stand age increased, the storage of SOC and TN increased. These results further indicated that restoration with S. cheilophila has positive impacts on the Gonghe Basin and has increased the capacity of SOC sequestration and N storage. The shrub's role as carbon sink is compatible with system management and persistence. The findings are significant for assessing C and N sequestration accurately in semi-arid degraded high, cold sandy regions in the future. [ABSTRACT FROM AUTHOR]

Published
2014
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23. Synthesis of Polyaluminum Chloride with a Membrane Reactor:  Operating Parameter Effects and Reaction Pathways

Author

Jia, Z. Q., He, F., and Liu, Z. Z.

Abstract

Polyaluminum chloride (PAC) is an important flocculant in potable water and wastewater treatment. Al13 or Alb is regarded as the most efficient species of PAC. A low base addition rate, small base drop sizes, and sufficient mixing usually favor the formation of PAC with higher Alb contents. In this paper, PAC was originally synthesized with a membrane reactor in which NaOH solution permeated through the micropores of an ultrafiltration membrane into AlCl3 solution gradually to reduce the NaOH droplets size to nanoscale, about 106 times smaller than that of conventional methods, resulting in a great reduction in the local supersaturation and precipitates generated and, subsequently, in an increase in the Alb content. The effects of the membrane molecular weight cutoff (MWCO) and reactant concentration on the species distribution were investigated. It was found that Alb increases with decreasing MWCO and reactant concentration under the experimental conditions used. A new plausible reaction pathway is also proposed that assumes that the hydrolysis and polymerization of Al3+ constitute a complex net of consecutive and parallel reactions and that the species distribution is mainly determined by the reactions kinetics.

Published
2004

26. Optimal time for cardiomyocyte transplantation to maximize myocardial function after left ventricular injury.

Author

Li RK, Mickle DA, Weisel RD, Rao V, and Jia ZQ

Subjects
Animals, Cicatrix pathology, Heart Ventricles pathology, Male, Rats, Rats, Sprague-Dawley, Ventricular Remodeling physiology, Cell Transplantation, Myocardial Infarction pathology, Myocardium cytology, Ventricular Dysfunction, Left pathology
Abstract

Background: This study was designed to determine the optimal time for cell transplantation after myocardial injury., Methods: The left ventricular free wall of adult rat hearts was cryoinjured and the animals were sacrificed at 0, 1, 2, 4, and 8 weeks for histologic studies. Fetal rat cardiomyocytes (transplant) or culture medium (control) were transplanted immediately (n = 8), 2 weeks (n = 8), and 4 weeks (n = 12) after cryoinjury. At 8 weeks, rat heart function, planimetry, and histologic studies were performed., Results: Cryoinjury produced a transmural injury. The inflammatory reaction was greatest during the first week but subsided during the second week after cryoinjury. Scar size expanded (p < 0.01) at 4 and 8 weeks. Cardiomyocytes transplanted immediately after cryoinjury were not found 8 weeks after cryoinjury. Scar size and myocardial function were similar to the control hearts. Cardiomyocytes transplanted at 2 and 4 weeks formed cardiac tissue within the scar, limited (p < 0.01) scar expansion, and had better (p < 0.001) heart function than the control groups. Developed pressure was greater (p < 0.01) in the hearts with transplanted cells at 2 weeks than at 4 weeks., Conclusions: Cardiomyocyte transplantation was most successful after the inflammatory reaction resolved but before scar expansion.

Published
2001
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27. Angiogenesis by endothelial cell transplantation.

Author

Kim EJ, Li RK, Weisel RD, Mickle DA, Jia ZQ, Tomita S, Sakai T, and Yau TM

Subjects
Animals, Cell Transplantation, Cyclosporine therapeutic use, Endothelial Growth Factors metabolism, Endothelium, Vascular cytology, Heart Injuries therapy, Immunosuppressive Agents therapeutic use, Lymphokines metabolism, Male, Myocardium pathology, Neovascularization, Physiologic, Protein Isoforms, Rats, Rats, Sprague-Dawley, Vascular Endothelial Growth Factor A, Vascular Endothelial Growth Factors, Endothelium, Vascular transplantation, Myocardial Revascularization methods
Abstract

Purpose: Myocardial angiogenesis may improve regional perfusion and perhaps function after cardiac injury. We evaluated the effect of endothelial cell transplantation into a myocardial scar on angiogenesis and ventricular function, as an alternative to angiogenic gene or protein therapy., Methods and Results: A transmural myocardial scar was created in the left ventricular free wall of rat hearts by cryoinjury. Allogeneic aortic endothelial cells were injected into the scar 2 weeks after cryoinjury. A cluster of transplanted cells was identified at the site of injection 1 day and 1 week after transplantation, but not after 2 weeks. The size of this cluster of transplanted cells decreased as vascular density in the transplanted scar tissue increased with time. Six weeks after transplantation, vascular density was significantly greater in transplanted hearts than in control hearts. Regional blood flow, by microsphere analysis, was greater in the transplanted rats. Systolic and diastolic ventricular function was similar between groups. In a second series of experiments, syngeneic aortic endothelial cells labeled with bromodeoxyuridine were transplanted 2 weeks after cryoinjury. Vascular density in the transplanted scar was greater than in controls. Labeled transplanted endothelial cells were identified forming part of the newly developed blood vessels. No difference in vascular density was found between allogeneic and syngeneic cell transplantation. Vascular endothelial growth factor was not expressed at greater levels in the transplanted cells or the myocardial scar., Conclusion: Transplanted endothelial cells stimulated angiogenesis, were incorporated into the new vessels, and increased regional perfusion in myocardial scar tissue, but did not improve global function in this cryoinjury rat model.

Published
2001
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28. The fate of a tissue-engineered cardiac graft in the right ventricular outflow tract of the rat.

Author

Sakai T, Li RK, Weisel RD, Mickle DA, Kim ET, Jia ZQ, and Yau TM

Subjects
Animals, Biocompatible Materials, Biomedical Engineering, Cells, Cultured, Gelatin Sponge, Absorbable, Male, Rats, Rats, Inbred Lew, Transplantation, Isogeneic, Absorbable Implants, Cell Transplantation, Heart Ventricles cytology, Myocardium cytology
Abstract

Objective: The synthetic materials currently available for the repair of cardiac defects are nonviable, do not grow as the child develops, and do not contract synchronously with the heart. We developed a beating patch by seeding fetal cardiomyocytes in a biodegradable scaffold in vitro. The seeded patches survived in the right ventricular outflow tract of adult rats., Methods: Cultured fetal or adult rat heart cells (1 x 10(6) cells) were seeded into a gelatin sponge (15 x 15 x 1 mm), and the cell number was expanded in culture for 1 or 3 weeks, respectively. The free wall of the right ventricular outflow tract in syngeneic adult rats was resected and repaired with either unseeded patches or patches seeded with either fetal or adult cardiomyocytes (n = 10 for each group). The patches were examined histologically over a 12-week period., Results: A significant inflammatory reaction was noted in the patch at 4 weeks as the scaffold dissolved. At 12 weeks, the gelatin scaffold had completely dissolved. Both types of the seeded cells were detected in the patch with 5-bromo-2'-deoxyuridine staining, and they maintained their continuity. Unseeded patches had an ingrowth of fibrous tissue. The patches became thinner between the fourth and the twelfth weeks in unseeded (P =.003), fetal (P =.0001), and adult (P =.07) cardiomyocyte groups as the scaffold dissolved. The control patch, but not the cell-seeded patches, was thinner than the normal right ventricular outflow tract. The endocardial surface area of each patch was covered with endothelial cells identified by factor VIII staining., Conclusions: A gelatin patch was used to replace the right ventricular outflow tract in syngeneic rats. The seeded cells survived in the right ventricular outflow tract after the scaffold dissolved 12 weeks after implantation. In addition, the unseeded patches encouraged the ingrowth of fibrous tissue as the scaffold dissolved and the patches remained completely endothelialized.

Published
2001
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29. Construction of a bioengineered cardiac graft.

Author

Li RK, Yau TM, Weisel RD, Mickle DA, Sakai T, Choi A, and Jia ZQ

Subjects
Adult, Animals, Biodegradation, Environmental, Cell Division, Cell Survival, Cells, Cultured, Fetal Heart cytology, Fetal Heart physiology, Fibroblasts physiology, Humans, Muscle, Smooth physiology, Myocardial Contraction, Rats, Ventricular Function, Biomedical Engineering, Bioprosthesis, Fibroblasts cytology, Heart Transplantation, Heart Ventricles cytology, Muscle, Smooth cytology
Abstract

Objectives: Currently available graft materials for repair of congenital heart defects cause significant morbidity and mortality because of their lack of growth potential. An autologous cell-seeded graft may improve patient outcomes. We report our initial experience with the construction of a biodegradable graft seeded with cultured rat or human cells and identify their 3-dimensional growth characteristics., Methods: Fetal rat ventricular cardiomyocytes, stomach smooth muscle cells, skin fibroblasts, and adult human atrial and ventricular cardiomyocytes were isolated and cultured in vitro. These cells were injected into or laid onto biodegradable gelatin meshes, and their rate of proliferation and spatial location within the mesh was evaluated by using a cell counter and histologic analysis., Results: Rat cardiomyocytes, smooth muscle cells, and fibroblasts demonstrated steady proliferation over 3 to 4 weeks. The gelatin mesh was slowly degraded, but this process was most rapid after seeding with fibroblasts. Human atrial cardiomyocytes proliferated within the gelatin meshes but at a slower rate than that of fetal rat cardiomyocytes. Human ventricular cardiomyocytes survived within the gelatin mesh matrix but did not increase in number during the 2-week duration of evaluation. Grafts seeded with rat ventricular cells exhibited spontaneous rhythmic contractility. All cell types preferentially migrated to the uppermost surface of each graft and formed a 300- to 500-microm thick layer., Conclusions: Fetal rat ventricular cardiomyocytes, gastric smooth muscle cells, skin fibroblasts, and adult human atrial cardiomyocytes can grow in a 3-dimensional pattern within a biodegradable gelatin mesh. Similar autologous cell-seeded constructs may eventually be applied to repair congenital heart defects.

Published
2000
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30. Autologous porcine heart cell transplantation improved heart function after a myocardial infarction.

Author

Li RK, Weisel RD, Mickle DA, Jia ZQ, Kim EJ, Sakai T, Tomita S, Schwartz L, Iwanochko M, Husain M, Cusimano RJ, Burns RJ, and Yau TM

Subjects
Analysis of Variance, Animals, Cells, Cultured, Chi-Square Distribution, Disease Models, Animal, Female, Heart Ventricles diagnostic imaging, Immunohistochemistry, Myocardial Infarction pathology, Radiopharmaceuticals, Swine, Technetium Tc 99m Sestamibi, Tomography, Emission-Computed, Single-Photon, Transplantation, Autologous, Ventricular Pressure physiology, Cell Transplantation, Myocardial Infarction physiopathology, Myocardial Infarction surgery, Myocardium cytology, Ventricular Function physiology
Abstract

Objective: Fetal cardiomyocyte transplantation improved heart function after cardiac injury. However, cellular allografts were rejected despite cyclosporine (INN: ciclosporin) therapy. We therefore evaluated autologous heart cell transplantation in an adult swine model of a myocardial infarction., Methods: In 16 adult swine a myocardial infarction was created by occlusion of the distal left anterior descending coronary artery by an intraluminal coil. Four weeks after infarction, technetium 99m-sestamibi single photon emission tomography showed minimal perfusion and viability in the infarcted region. Porcine heart cells were isolated and cultured from the interventricular septum at the time of infarction and grown in vitro for 4 weeks. Through a left thoracotomy, either cells (N = 8) or culture medium (N = 8) was injected into the infarct zone., Results: Four weeks after cell transplantation, technetium 99m-sestamibi single photon emission tomography demonstrated greater wall motion scores in the pigs receiving transplantation than in control animals (P =.01). Pigs receiving transplantation were more likely to have an improvement in perfusion scores (P =.03). Preload recruitable stroke work (P =.009) and end-systolic elastance (P =. 02) were greater in the pigs receiving transplantation than in control animals. Scar areas were not different, but scar thickness was greater (P =.02) in pigs receiving transplantation. Cells labeled with bromodeoxyuridine in vitro could be identified in the infarct zone 4 weeks after transplantation. Swine receiving transplantation gained more weight than control animals (P =.02)., Conclusion: Autologous porcine heart cell transplantation improved regional perfusion and global ventricular function after a myocardial infarction.

Published
2000
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31. Autologous heart cell transplantation improves cardiac function after myocardial injury.

Author

Sakai T, Li RK, Weisel RD, Mickle DA, Kim EJ, Tomita S, Jia ZQ, and Yau TM

Subjects
Animals, Cells, Cultured, Heart Atria, In Vitro Techniques, Male, Myocardial Contraction, Rats, Rats, Sprague-Dawley, Transplantation, Autologous, Ventricular Function, Left, Ventricular Pressure, Ventricular Remodeling, Cell Transplantation, Myocardium cytology, Ventricular Function
Abstract

Background: Fetal ventricular cardiomyocyte transplantation into a cardiac scar improved ventricular function, but these cells were eventually eliminated by rejection. We therefore examined the feasibility of autologous adult heart cell transplantation., Methods: A transmural scar was produced in the left ventricular free wall of adult rats by cryoinjury. The left atrial appendage was harvested, and the atrial heart cells were cultured and their number expanded ex vivo. Three weeks after cryoinjury, either a cell suspension (2 x 10(6) cells, n = 12 rats, transplant group) or culture medium (n = 10 rats, control group) was injected into the scar. Rats having a sham operation (n = 5) did not undergo cryoinjury or transplantation with cells or culture medium., Results: Five weeks after injection, ventricular function was evaluated in a Langendorff preparation, measuring systolic, diastolic, and developed pressures over a range of intraventricular balloon volumes. Systolic and developed pressures were greater in the transplant group than in the control group (p = 0.0001). Rats with a sham operation had the greatest systolic, diastolic, and developed pressures (p = 0.0001). Histologic studies demonstrated survival of the transplanted heart cells within the scar. The area of the scar was smaller (p = 0.0003) and its thickness greater (p = 0.0003) in rats in the transplant group. Left ventricular chamber volume was smaller in the transplant group (p = 0.043)., Conclusions: Transplantation of autologous cultured adult atrial heart cells limited scar thinning and dilatation and improved myocardial function compared with results in control hearts. This technique may lead to a novel therapy to prevent scar expansion after a myocardial infarction and prevent the development of congestive heart failure.

Published
1999
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32. Fetal cell transplantation: a comparison of three cell types.

Author

Sakai T, Li RK, Weisel RD, Mickle DA, Jia ZQ, Tomita S, Kim EJ, and Yau TM

Subjects
Animals, Cardiac Volume physiology, Cardiomyopathies surgery, Cicatrix surgery, Cyclosporine therapeutic use, Diastole, Heart physiopathology, Heart Ventricles cytology, Immunosuppressive Agents therapeutic use, Intestines cytology, Male, Myocardial Contraction physiology, Rats, Rats, Sprague-Dawley, Skin cytology, Ventricular Function, Left physiology, Ventricular Pressure physiology, Ventricular Remodeling physiology, Cell Transplantation methods, Fetal Tissue Transplantation methods, Fibroblasts transplantation, Muscle, Smooth cytology, Myocardium cytology
Abstract

Objective: We have previously reported that fetal cardiomyocyte transplantation into myocardial scar improves heart function. The mechanism by which this occurs, however, has not been elucidated. To investigate possible mechanisms by which cell transplantation may improve heart function, we compared cardiac function after transplantation of 3 different fetal cell types: cardiomyocytes, smooth muscle cells (nonstriated muscle cells), and fibroblasts (noncontractile cells)., Methods: A left ventricular scar was created by cryoinjury in adult rats. Four weeks after injury, cultured fetal ventricular cardiomyocytes (n = 13), enteric smooth muscle cells (n = 10), skin fibroblasts (n = 10), or culture medium (control, n = 15 total) were injected into the myocardial scar. All rats received cyclosporine A (INN: ciclosporin). Four weeks after transplantation, left ventricular function was evaluated in a Langendorff preparation., Results: The implanted cells were identified histologically. All transplanted cell types formed tissue within the myocardial scar. At an end-diastolic volume of 0.2 mL, developed pressures in cardiomyocytes group were significantly greater than smooth muscle cells and skin fibroblasts groups (cardiomyocytes, 134% +/- 22% of control; smooth muscle cells, 108% +/- 14% of control; skin fibroblasts, 106% +/- 17% of control; P =.0001), as were +dP/dt(max) (cardiomyocytes, 119% +/- 37% of control; smooth muscle cells, 98% +/- 18% of control; skin fibroblasts, 92% +/- 11% of control; P =. 0001) and -dP/dt(max) (cardiomyocytes, 126% +/- 29% of control; smooth muscle cells, 108% +/- 19% of control; skin fibroblasts, 99% +/- 16% control; P =.0001)., Conclusions: Fetal cardiomyocytes transplanted into myocardial scar provided greater contractility and relaxation than fetal smooth muscle cells or fetal fibroblasts. The contractile and elastic properties of transplanted cells determine the degree of improvement in ventricular function achievable with cell transplantation.

Published
1999
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33. Smooth muscle cell transplantation into myocardial scar tissue improves heart function.

Author

Li RK, Jia ZQ, Weisel RD, Merante F, and Mickle DA

Subjects
Animals, Blood Pressure, Cells, Cultured, Cicatrix pathology, Male, Muscle, Smooth cytology, Muscle, Smooth embryology, Myocardial Contraction, Myocardial Infarction complications, Myocardial Infarction pathology, Myocardial Infarction physiopathology, Rats, Rats, Sprague-Dawley, Stomach cytology, Cicatrix surgery, Fetal Tissue Transplantation, Heart physiopathology, Muscle, Smooth transplantation, Myocardial Infarction surgery
Abstract

This study was designed to evaluate the effect of smooth muscle cell transplantation into myocardial ventricular scar formed by cryo-necrosis. The left ventricular free wall (LVFW) of adult rats was cryo-necrosed. At 4 weeks after cryo-injury cultured fetal rat stomach smooth muscle cells (transplanted group, n = 10) or culture medium (control, n = 10) were transplanted. Sham animals (n = 8) were similarly operated but without cryo-necrosis and transplantation. The animals were administered a daily maintenance dose of cyclosporin A (5 mg/kg). At 8 weeks after cryo-injury, heart function was evaluated using a Langendorff preparation. Myocardial scar and transplanted cells were assessed histologically. Transplanted smooth muscle cells survived and formed smooth muscle cell tissue, as assessed by immunostaining against smooth muscle cell actin, within the myocardial scar. In the control hearts no muscle tissue was found in the scar. Angiogenesis occurred (P < 0.001) in the transplanted scar compared to the control scar. The transplanted cells increased the scar thickness (P < 0.01) by hyperplasia and prevented (P < 0.001) the dilatation of the ventricular chamber size compared to the controlled hearts. For physiological left ventricular volumes of 0.04 to 0.28 ml, the systolic and developed pressures in the transplanted group were greater (P < 0.001) than the control group, but less (P < 0.001) than those of the sham group. Transplanted smooth muscle cells formed smooth muscle tissue in myocardial scar tissue and improved contractile function compared to control hearts.

Published
1999
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34. Natural history of fetal rat cardiomyocytes transplanted into adult rat myocardial scar tissue.

Author

Li RK, Mickle DA, Weisel RD, Mohabeer MK, Zhang J, Rao V, Li G, Merante F, and Jia ZQ

Subjects
Animals, Cicatrix, Female, Pregnancy, Rats, Rats, Sprague-Dawley, Cell Transplantation, Fetal Heart cytology, Fetal Tissue Transplantation
Abstract

Background: Fetal rat cardiomyocytes transplanted into left ventricular scar tissue of the adult rat heart limit scar expansion and improve heart function. This study determined morphologic changes of transplanted fetal rat cardiomyocytes in myocardial scar tissue., Methods and Results: The left ventricles of 500-g Sprague-Dawley rats were cryodamaged. At 4 weeks after myocardial injury, a transmural scar (54+/-11 mm2) (mean+/-1 SDak) formed at the apex (n=6). Cardiomyocytes freshly isolated from 18-day-gestation Sprague-Dawley rat hearts were transfected with plasmid containing the beta-galactosidase and then injected into the 4-week-old scar tissue. Cell culture medium was injected into the scar tissue of control animals. At 4 weeks posttransplantation, the cardiomyocytes had formed cardiac tissue (20.7+/-6.9 mm2, n=14), which stained positively for beta-galactosidase activity in the scar (90.4+/-25 mm2, n=14). The transplanted cardiomyocytes formed sarcomeres and were linked by junctions composed of desmosomes and fascia adherens. Lymphocyte infiltration occurred despite use of cyclosporin A. No myocardial tissue was found in the scar tissue of the control animals (n=14). More arterioles and venules were found (P<.01) in the cardiomyocyte grafts (1.2+/-0.6 vessel/0.8 mm2; n=14) than in the control scar tissue (0.1+/-0.1 vessels/0.8 mm2; n=14). At 20 weeks post-transplantation, the transplant tissue size (6+/-6 mm2; n=7) was smaller (P=.007) than 4-week old transplant, and the scar (162+/-46 mm2; n=7) was larger (P=.005) than 4-week-old scar. Lymphocyte infiltration was still present among the remaining transplanted cells., Conclusions: This study demonstrated that cardiac tissue formed by transplanted fetal cardiomyocytes in the myocardial scar tissue decreased in size with time probably secondary to rejection.

Published
1997

35. Cardiomyocyte transplantation improves heart function.

Author

Li RK, Jia ZQ, Weisel RD, Mickle DA, Zhang J, Mohabeer MK, Rao V, and Ivanov J

Subjects
Animals, Cells, Cultured, Coronary Circulation, Heart Rate, Male, Myocardium cytology, Rats, Rats, Sprague-Dawley, Cell Transplantation, Fetal Heart cytology, Fetal Tissue Transplantation, Heart physiopathology, Heart Ventricles surgery
Abstract

Background: Transplantation of cultured cardiomyocytes into myocardial scar tissue may prevent heart failure., Methods: Scar tissue was produced in the left ventricular free wall of 15 rats (weight, 450 g) by cryoinjury. Seven animals had operation only and survived for 8 weeks (sham group). Four weeks after cryoinjury, cultured fetal rat cardiomyocytes or culture medium was injected into the scar tissue of transplantation (n = 5) and control (n = 5) animals, respectively. Five other rats were sacrificed for scar assessment. Eight weeks after cryoinjury heart function in the transplantation, control, and sham groups was measured using a Langendorff preparation. Histologic studies were performed to quantify the extent of the scar and the transplanted cells., Results: Four weeks after cryoinjury, 36% +/- 4% (mean +/- 1 standard error) of the left ventricular free wall surface area was scar tissue. At 8 weeks, the scar size had increased (p < 0.01) to 55% +/- 3% in the control group. Although the scar size (43% +/- 2%) in the transplantation group at 8 weeks was not significantly different from that at 4 weeks, it was less (p < 0.05) than that in the control group. Hearts in the sham group had no scar tissue. The transplanted cardiomyocytes had formed cardiac tissue within the myocardial scar. Systolic and developed pressures in the transplantation group hearts were greater (p = 0.0001) than in the control group hearts but less (p < 0.01) than those in the sham group hearts., Conclusions: The transplanted cardiomyocytes formed cardiac tissue in the myocardial scar, limited scar expansion, and improved heart function compared with findings in the control hearts.

Published
1996
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