雾化吸入羟基喜树碱在兔体内分布及肺器官中药代动力学研究

目的 研究雾化吸入羟基喜树碱在兔体内分布及肺器官中药物动力学特点。方法 采用HPLC法测定不同时间点兔血浆和肺组织中羟基喜树碱浓度 ,分析雾化吸入给药后的组织分布特点 ,并对雾化吸入给药后的肺器官中药物浓度数据进行了药物动力学分析。结果 雾化吸入给药后肺组织中的药物含量最高 ,而血浆和其它组织中的含量极低。HCPT在肺组织内浓度随着时间的延长而逐渐降低 ,其药代动力学规律可用二室模型来描述。结论 雾化吸入羟基喜树碱能维持肺中的高浓度 。

器官血流动力学新认知:动脉—灌注—静脉

重症患者器官血流动力学改变是导致器官功能受损的核心。器官灌注压是保证器官血流的直接动力,受到入器官压力(动脉端的压力)和出器官压力(静脉端压力)的影响。不同器官对血流的调整有独特的灌注压力需求和调节系统,以匹配自身生理需求。动脉端作为器官灌注的供给侧,主要通过灌注压力和调节系统以保证器官的血流。自主调节能力不同的器官对于动脉灌注压的需求并不完全相同,临床应根据相应的自主调节范围寻找合适的动脉端灌注压。器官血流灌注不仅取决于供给侧,还受静脉回流的影响,重要器官的动静脉梯度改变可影响器官血流灌注。此外,由于距离心脏远近不同以及受器官自身特异性的影响,不同器官对于静脉回流障碍的耐受程度不完全一致。临床进行血流动力学干预时,应关注不同压力变化对器官灌注的影响,进而真正实现重症治疗器官化。

生物固体力学进展

生物力学是多种学科相互交叉、相互渗透所形成的一门新兴边缘学科。在我国仅有二十几年的历史。生物固体力学是生物力学的一大分支,本文就其三大方面:骨力学、软组织力学和器官力学的发展、主要成就及发展趋向、前沿研究课题作了简明的综述。

同种异体肾移植术患者血流动力学的变化及其调控

选择2005-01/2006-12于江门市中心医院在硬膜外麻醉下行同种异体肾移植的患者38例,均知情同意。记录肾移植手术麻醉前、血流开放前、血流开放后、手术结束时患者的血流动力学指标,包括平均动脉压、心率、中心静脉压的变化。肾移植患者血流开放后的平均动脉压、中心静脉压均显著低于麻醉前及血流开放前(P<0.05～0.01),心率显著高于血流开放前(P<0.05)。硬膜外麻醉下肾移植术围手术期的血流动力学随手术步骤变化而变化,供肾恢复血供后变化最大。

靶向给药系统的体内药物动力学分析

建立靶向给药系统的体内药物动力学模型。以房室模型理论为依据,结合质量守恒原理,建立了数学模型,推导出了靶器官的药时函数表达式,并用实验数据验证了其准确性。根据所得靶器官的药时函数表达式,用统计矩方法分析了靶向给药系统的靶器官药物动力学规律,给出了靶器官的药物动力学参数。结果表明:靶器官中的药时函数表达式与实验数据能很好地拟合。我们所建立的药时函数表达式能很好地刻画靶向制剂体内药物动力学规律。

Dynamics of soil organic carbon following land-use change:insights from stable C-isotope analysis in black soil of Northeast China

Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and inconsistent.Our aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0–100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C_4) and from natural vegetation (C_3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0–10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C_4 above 30 cm soil depth increased by 4.5%–5% or 0.11–0.12 g·kg^(-1) on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation abandonment.The increase in the percentage of C_4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C_4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment.

Design of a New Multifunctional Wheelchair-bed

Currently, the aging of the population has become the world＇s social problem. With the increase of aging population and lots of disability, paralysis makes nursing care more difficult. Because of many elderly cannot get timely care, the phenomenon that the elderly have chronic diseases has become more and more serious. It is important to research and develop a new product which can help the elderly and the disabled for improving the quality of their life. This paper suggests a new type of mnltifunctional self-caring wheelchair-bed, which is combined with a wheelchair and a bed. The bed can realize the free conversion among user sitting, leg lifting and lying down, and also can implement the function of turning on sides. Particularly, the wheelchair can be easily separated from the bed and combined, so that patients and the elderly can move freely using it, and even it can be transformed into a standing type to satisfy the patient＇s standing demand, and to a certain extent, carry out the purpose of rehabilitation.

NH_2 Ion Implantations Induced Superior Cell Attachment of Carbon Nanotubes

Objective： Cell and platelet attachment on the multiwalled carbon nanotubes （MWCNTs） were studied by ion implantation. Methods： NH2 ion implantation was performed at the energy of 30 keV with the fluence of 1 x 1016 ions/era2 at room temperature. Results： The cell attachment tests showed interesting results in that the number of the platclets adhering on the surface of the MWCNTs was reduced significantly after NH2 ion implantation, whereas, mouse fibroblast cells （L929） cultured on NH2 ion implanted MWCNTs displayed higher cell-viability, proliferation, and stretching compared with MWCNTs. Conclusion： No appreciable change in the tensile strength and the optical transmittance of the implanted samples was observed. X-ray photoelectron spectroscopy （XPS） analysis showed that NH2 ion implantation caused the formation of new N-containing groups.

Effect of Inflow and Outflow Angles on the Computational Hemodynamics in Abdominal Aortic Aneurysm

To help the clinical screening and diagnosis of abdominal aortic aneurysm(AAA), we evaluated the effect of inflow angle (IA) and outflow bifurcation angle(BA) on the distribution of blood flow and wall shear stress(WSS) in an idealized AAA model. A 2D incompressible Newtonian flow is assumed and the computational simulation is performed using finite volume method. The results showed that the largest WSS often located at the proximal and the distal end of the AAA. An increase in IA resulted in an increase in maximum WSS. We also found that WSS was maximal when BA was 90°. IA and BA are two important geometrical factors, they may help AAA risk assessment along with the commonly used AAA diameter.

Effect of Osteocytes Subjected to Fluid Flow on Osteoblasts

Osteocytes act as mechanosensors in bone, which can send mechanical signals directly to osteoblasts through gap junctions. However, under physiological conditions the number of gap junctions is limited because of the quantity variance of the two kinds of cells. In this study, the possibility of indirect interaction between these two cells was investigated. A new flow champer was designed in which osteocytes and osteoblasts were cocultured in two champers separately. 0steocytes were exposed to fluid flow and then the ALP activity, osteocalcin and osteopotin of osteoblasts were determined. The results showed that either ALP activity or production of osteocalcin and osteopotin in osteoblasts that were cocuhured with sheared osteocytes increased, which indicated that osteocytes could regulate osteoblasts indirectly through some soluble factors.

Optimization of Cross-section of Stent Wire in Trapezoidal Shape for the Treatment of Intracranial Aneurysm

Grant sponsor： National Natural Science Foundation of China; grant number： 10972016 and 81171107; grant sponsor： Natural Science Foundation of Beijiug; grant number： 3092004

The in vivo 3D Optic Nerve Head Modeling Based on Human Multimodality Images

Introduction： The human optic nerve head （ONH） is vulnerable to the damage in glaucomatous high intraocular pressure （IOP）. In order to analyze the human ONH head stress and deformation in high IOP, an in vivo three-dimensional （3D） ONH model was reconstructed by optical coherence tomography （OCT） images and magnetic resonance imaging （MRI） images. Materials and Methods： A human eye was scanned by MRI and OCT in serial imaging protocol. The sclera and ONH were segmented from the images, and 3D models were reconstructed by multimodality image registration. Through the morphological segmentation, part of lamina cribrosa （LC） was acquired and reconstructed in combination with the ONH and sclera. Results： The models of ONH and sclera were got, the part of LC was included in the model. In the analysis of FEM, the ONH was compressed and the cup/disk ratio was changed obviously in high glaucomatous IOP. Discussion： This study described a method to build a 3D in vivo ONH model by image processing. It can be used in biomechanieal analysis, and provide the stress state of ONH for the research about the fundus damage of glaucoma.

Design of a Novel Waterproof Electronic Sphygmomanometer

A novel waterproof electronic sphygmomanometer is presented in this paper, the special design of sealing structure is used in this sphygmomanometer that allows the system to function normally in water. The system also adopts the rigid air cylinder as air source to ensure accurate detection and chooses the MP3VS050 piezoresistive transducer to ensure the measurement precision of the systolic and diastolic pressure. TI＇s MSP430FC,437 is used as the central processor so that the system can be of advantages of low-power, fast digital processing and high-reliability. The sphygmomanometer was validated by three groups of participants. The experimental data indicates that the measured values of this waterproof electronic sphygmomanometer are consistent with the results of common electric sphygmomanometer, the measure error is less than 5 mmHg, and the system is stable and credible. So the waterproof electronic sphygmomanometer can realize real-time monitoring of blood pressure and heart rate in the water and other special environment.

Optimal Performance Characteristics of Subcritical Simple Irreversible Organic Rankine Cycle

Based on the theory of finite time thermodynamics, a subcritical simple irreversible organic Rankine cycle(SSIORC) model considering heat transfer loss and internal irreversible losses is established in this paper. The total heat transfer surface area is taken as a constraint, and R245fa is adopted as working fluid of the cycle in the performance optimization. The evaporator heat transfer surface area and mass flow rate of the working fluid are optimized to obtain the maximum power output and thermal efficiency of the SSIORC, respectively. In addition, the influences of the internal irreversibilities on the optimal performances are also investigated. The results show that when the evaporator heat transfer surface area is varied, the relationship between power output and thermal efficiency is a loop-shaped curve, and there exist maximum power output and thermal efficiency points, respectively. However, the two maximum points are very close to each other. When the mass flow rate of the working fluid is varied, the relationship between power output and thermal efficiency is a parabolic-like curve. With the decreases of expander and pump irreversible losses, the performances of the irreversible SSORC are close to those of the endoreversible SSORC with the only loss of heat transfer loss.