Biomedical subjects
Publications and source records attributed to G L Zhu.
The features and composition of Rotational Gamma Knife are mainly introduced in this paper. The open architecture double PLCs and motion controller are used to fit special requirements of the Rotational Gamma Knife and thus to ensure its high reliability. In the end, safety measures which should be taken for patients, doctors and equipments are discussed.
Rapid changes in turgor pressure (P:) and temperature (T:) are giving new information about the mechanisms of plant growth. In the present work, single internode cells of the large-celled alga Chara corallina were used as a model for plant growth. P was changed without altering the chemical environment of the wall while observing growth without elastic changes. When P: was measured before any changes, the original growth rate bore no relationship to the original P. However, if P of growing cells was decreased, growth responded immediately without evidence for rapid changes in wall physical properties. Growth occurred only above a 0.3 MPa threshold, and increasing P caused small increases in growth that became progressively larger as P rose, resulting in a curvilinear response overall. The small changes in growth close to the threshold may explain early failures to detect these responses. When T was lowered, the elastic properties of the cell were unaffected, but growth was immediately inhibited. The lower T caused P to decrease, but returning P to its original value did not return growth to its original rate. The decreased P at low T occurred because of T effects on the osmotic potential of the cell. At above-normal P, growth partially resumed at low T Therefore, growth required a P-sensitive process that was also T-sensitive. Because elastic properties were little affected by T, but growth was markedly affected, the process is likely to involve metabolism. The rapidity of its response to P and T probably excludes the participation of changes in gene expression.
UNLABELLED: Western medicines (WM) and the combining WM-TCM were used to treat congestive heart failure (CHF). The three groups of WM were: Digoxin with dihydro-chlorothiazide, captopril with nifedipium, and dobutamine. The three groups of combining WM-TCM were: the above-mentioned three groups of WM with Jisen Shenqi Pill (JSSQ) respectively. The result observed: Total effective rate was 82%, marked effective rate was 43%, the rates of the WM groups were 77% and 36% respectively, and the groups of combining WM-TCM were 88% and 53%. Total mortality was 8.66% (the WM groups was 11.76%, the groups of combining WM-TCM 5%). Cardio-function indexes observed in the groups of combining WM-TCM were obviously improved, including HR, SV, CI, EF, FS and A/E (P < 0.01). HR, CI and SV in the groups of WM were also significantly improved (P < 0.05) except for EF, FS and A/E (P > 0.05). CONCLUSIONS: (1) The treatment of CHF should depend on various conditions and different symptoms in selecting medicines, so that individual treatment could reach the optimal effects. (2) The treatment method of combining WM-TCM could significantly promote effective rate, reduce toxic and side-effects and lower the rate of mortality. (3) JSSQ could obviously improve the function of ventricular diastole and its mechanism might be that the reduced density of beta-receptor was increased.
A new method, the turgor clamp, was developed to test the effects of turgor on cell enlargement. The method used a pressure probe to remove or inject cell solution and change the turgor without altering the external environment of the cell walls. After the injections, the cells were permanently at the new turgor and required no further manipulation. Internode cells of Chara corallina grew rapidly with the pressure probe in place when growth was monitored with a position transducer. Growth-induced water potentials were negligible and turgor effects could be studied simply. As turgor was decreased, there was a threshold below which no growth occurred, and only reversible elastic/viscoelastic changes could be seen. Above the threshold, growth was superimposed on the elastic/viscoelastic effects. The rate of growth did not depend on turgor. Instead, the rate was highly dependent on energy metabolism as shown by inhibitors that rapidly abolished growth without changing the turgor. However, turgors could be driven above the maximum normally attainable by the cell, and these caused growth to respond as though plastic deformation of the walls was beginning, but the deformation caused wounding. Growth was inhibited when turgor was changed with osmotica but not inhibited when similar changes were made with the turgor clamp. It was concluded that osmotica caused side effects that could be mistaken for turgor effects. The presence of a turgor threshold indicates that turgor was required for growth. However, because turgor did not control the rate, it appears incorrect to consider the rate to be determined by a turgor-dependent plastic deformation of wall polymers. Instead, above the turgor threshold, the rapid response to energy inhibitors suggests a control by metabolic reactions causing synthesis and/or extension of wall polymers.
A double pressure probe technique was used to measure simultaneously water flows and hydraulic parameters of individual cells and of excised roots of young seedlings of maize (Zea mays L.) in osmotic experiments. By following initial flows of water at the cell and root level and by estimating the profiles of driving forces (water potentials) across the root, the hydraulic conductivity of individual cell layers was evaluated. Since the hydraulic conductivity of the cell-to-cell path was determined separately, the hydraulic conductivity of the cell wall material could be evaluated as well (Lp(cw) = 0.3 to 6.10(-9) per meter per second per megapascal). Although, for radial water flow across the cortex and rhizodermis, the apoplasmic path was predominant, the contribution of the hydraulic conductance of the cell-to-cell path to the overall conductance increased significantly from the first layer of the cortex toward the inner layers from 2% to 23%. This change was mainly due to an increase of the hydraulic conductivity of the cell membranes which was Lp = 1.9.10(-7) per meter per second per megapascal in the first layer and Lp = 14 to 9.10(-7) per meter per second per megapascal in the inner layers of the cortex. The hydraulic conductivity of entire roots depended on whether hydrostatic or osmotic forces were used to induce water flows. Hydrostatic Lp(r) was 1.2 to 2.3.10(-7) per meter per second per megapascal and osmotic Lp(r) = 1.6 to 2.8.10(-8) per meter per second per megapascal. The apparent reflection coefficients of root cells (sigma(s)) of nonpermeating solutes (KCI, PEG 6000) decreased from values close to unity in the rhizodermis to about 0.7 to 0.8 in the cortex. In all cases, however, sigma(s) was significantly larger than the reflection coefficient of entire roots (sigma(sr)). For KCI and PEG 6000, sigma(sr) was 0.53 and 0.64, respectively. The results are discussed in terms of a composite membrane model of the root.