磁刺激用平面线圈结构的优化研究

文中建立了采用任意形状平面线圈磁刺激仪的RLC模型，给出了模型参数的计算方法。为了优化线圈，将磁刺激仪线圈的性能指标分为反映线圈输出性能的峰值磁能和反映线圈结构的几何变量。在磁刺激激活函数达到阈值条件下，调整平面螺旋线圈的结构并计算出依赖于线圈结构参数的输出性能值，从而，寻找最优的线圈几何参数。优化结果表明：线圈外半径是关键因素，给定阈值条件，选择合适的线圈外半径，可以大大降低线圈峰值磁能；另外，现在使用的圆环线圈并非最优，D形线圈优于圆环线圈。     

颈椎前路椎体间微创融合器的生物力学实验研究

目的评价植入镍钛记忆合金微创融合器(NiTi-TFC/C)的颈椎节段的稳定性及压缩力学性能。方法采集24只羊颈椎标本随机分为4组,每组6份,四组处理分别为:单取髓核组、自体髂骨植骨组、微创融合器组和钛制融合器组(InterFix)。所有标本进行前路减压,并对后3组进行椎间融合术。分别对各组标本进行生物力学测试并进行比较。结果微创融合器组与钛制融合器组在强度、刚度及扭转力学等方面无显著性差异(P>0.05)。而微创融合器组与自体髂骨植骨组具有显著性差异(P<0.05)。最大承载力为12050N。结论该微创融合器强度大、刚度高、抗扭转能力强,具有良好的抗压能力,为颈椎融合提供新型的融合装置。     

Modelling HA protein-mediated interaction between an influenza virus and a healthy cell: pre-fusion membrane deformation.

We present a mathematical model for pre-fusion interaction between an influenza virus and a healthy cell. Our model describes the role played by hemagglutinin (HA) protein clusters in bringing the viral membrane into close contact with the host cell membrane as a first step of the fusion process between the two membranes. The viral membrane is modelled as a lipid bilayer with bending rigidity. Using the calculus of variations, we compute the deformation of the viral membrane under the influence of HA protein clusters. Our numerical results support the hypothesis of dimple formation in the fusion site proposed in the literature. The asymmetric nature of the protein molecules due to various reasons such as tilting is the primary cause for the dimple formation. We discuss the effects of spontaneous curvature, the protein cluster radius, fusion-site size and the bending moment exerted by the protein cluster. We also examine the effects of membrane tension and the presence of a host cell on the dimple shape. Our results support previous experimental observations.     

Effect on EEG responses of removing ocular artefacts by proportional EOG subtraction

Work undertaken to investigate the effect on EEG responses of ocular artefact removal by proportional electro-oculogram subtraction using the least-squares method is reported. The ocular artefact model and the least-squares approach to estimation of the model parameters and hence of the EEG waveform, including the response, are described. Results are presented to show that the response shapes become modified if ocular artefact removal is implemented recursively. This happens because the response is incorrectly treated as part of the random background EEG. The solution is to incorporate a model of the response within the ocular artefact removal algorithm. The results of tests on simulated data confirm these conclusions. The results of the incorporation of response models in removing ocular artefacts from CNV recordings are presented. Even with modelling recursive ocular artefact removal is found to modify the shape of the CNV, and so reliable results can only be obtained if the removal is implemented nonrecursively. Evidence is given that it is advisable to remove DC levels from the recorded data.     

细胞核形态和DNA指数分析在星形细胞瘤分级诊断中的应用

目的 探索自动图像分析系统在胶质瘤分级诊断中的应用。方法 采用自行设计组装的MIPS-I型自动图像分析系统对3个级别星形细胞瘤的细胞核形态和DNA指数(倍体)同时进行原位定量测定。结果 在星形细胞瘤分级诊断中，5项反映核形态的参数诊断正确率为56．3％；代表核DNA改变的7项参数诊断正确率为70．8％；综合应用12项参数诊断正确率为75％。结论 细胞核形态和DNA指数分析可作为星形细胞瘤分级诊断的参考指标之一。     

Normal and homogeneous red blood cell populations over a wide range of hyper-iso-hypotonic media

The volumes of human erythrocytes after rapid and gradual swelling in hypotonic NaCl media were measured using a Coulter Counter Z_B at temperatures of +4°C and +20°C together with potassium leakage, the degree of hemolysis and the ‘returning volume’, i. e., the volume in an isotonic solution to which the cells will return from that in a hypotonic solution. The methodological and systematic errors in the volume measurements were corrected by taking into account the shape dependence of the Coulter Counter and the change in cell population during hemolysis, whereafter the measured cell volume values and the comparison between them become more reliable. The curves for cell volume as an inverse function of osmotic pressure appeared to be non-linear. The slopes were small at first but shoed a rapid increase as the cells approached their maximal volume. The critical hemolytic volume was approx.8% higher at +20°C after both rapid and gradual swelling than at +4°C and approx.4% higher after a gradual swelling as compared with a rapid swelling both at +4°C and +20°C.A decrease in temperature resulted in an increase in the critical osmotic pressure both in rapid and gradual hemolysis, but did not greatly affect the amount of prelytic K⁺ leakage. The critical osmotic pressure was smaller in gradual hemolysis than in rapid hemolysis and the prelytic K⁺ leakage was doubled at both +4°C and +20°C.The shifts in osmotic fragility as a function of temperature may be due to differences in the visco-elastic properties of the cell membrane, but the shifts in osmotic fragility as a function of swelling rate may be connected with differences in potassium leakage and membrane stretch.     

Quality validation of platelets obtained from the Haemonetics and Trima Accel automated blood-collection systems

BackgroundPlatelet transfusion is required to treat haemo-oncology or trauma patients. Platelet apheresis (PA) performed with apheresis equipment has increased rapidly in recent years. Leucocyte-reduced platelet apheresis (LRPA) can reduce the risk of platelet refractoriness and febrile nonhemolytic transfusion reactions (FNHTRs) for transfusion. Accordingly, this study aimed to investigate and compare the platelet metabolic and functional responses between PA performed with Haemonetics and LRPA performed with Trima Accel cell separator.MethodsThe qualities of platelets collected through PA and LRPA were evaluated in terms of visual appearance, morphology, platelet-aggregation changes, metabolic activities, and bacterium-screening test during 5-day storage. Statistical analyses included two-sample t-test and generalised estimating equation(GEE) method.ResultsDuring 5-day storage in LRPA, residual leucocytes were all <1.0×10⁶, and the parameters of platelet function were as follows: platelet aggregated to agonists such as adenosine 5′-diphosphate (ADP) and collagen, and the extent of shape change and pO₂ showed no statistically significant difference between PA and LRPA. The hypotonic shock reaction (HSR) on days 0, 1, and 3 were significantly higher in LRPA than in PA (71.78±6.92 vs. 64.10±7.42; P=0.002; 71.53±8.98 vs. 62.96±9.84; P=0.007; 68.05±7.28 vs. 57.76±6.80; P<0.0001, respectively). Values of mean platelet volume (MPV) were statistically larger in PA than in LRPA on days 0, 1, and 3. On day 5, the swirling score was higher in LRPA than in PA. The mean lactate levels had no statistically significant difference between PA and LRPA. Moreover, no growth was observed through bacterium-screening test conducted on 40 samples.ConclusionComparison of LRPA and PA products collected from the Trima Accel and Haemonetics automated blood-collection systems, respectively, revealed that both products possessed good platelet qualities even though additional processes are needed to reduce leucocytes. Furthermore, investigating the outcomes of other apheresis instruments with focus on the safety of donors, products, and recipients is necessary.     

身体形态指数ABSI和身体圆度指数BRI的发展与应用

目的 对身体形态指数(ABSI)和身体圆度指数(BRI)的发展进行介绍,并对其应用情况进行综述,为人体形态测量提供参考。方法 在Pubmed、中国知网等电子文献数据库中进行文献检索,详尽收录迄今ABSI与BRI对高血压、糖尿病、代谢综合征、心血管疾病等常见疾病的发病率以及全因死亡率预测的相关研究。结果 ABSI与BRI均对高血压、糖尿病、代谢综合征、心血管疾病发病呈现出一定的预测能力。其中,BRI在预测糖尿病、代谢综合征发病方面优于ABSI,但与身体质量指数、腰围、臀围、腰高比等传统测量指标相比,并未表现出显著的差异。ABSI对全因死亡率的预测能力则明显优于传统测量指标和BRI。结论 ABSI与BRI作为两项新的形态学指标,是BMI等传统身体指数测量的补充,对疾病发病具有一定的预测能力和应用性。今后的研究可以从两项指标对疾病的单独作用以及与传统指标的联合作用着手,同时探索其在不同社会人口学特征人群中的拟合情况,提供更有利的研究证据和科学积累。     

射野孔径形状控制器对直肠癌快速容积旋转调强放射治疗计划质量、机器传输能力和准确性的影响研究

目的:研究Eclipse15.5治疗计划系统中射野孔径形状控制器(ASC)对直肠癌快速(RapidArc)容积旋转调强放射治疗(VMAT)计划质量、机器传输能力和剂量传输准确性的影响。方法:选取医院收治的20例直肠癌患者,对每个病例生成ASC"off"、ASC"verylow"、ASC"moderate"和ASC"veryhigh"共4组RapidArc对照计划。其中ASC调节等级分别设置为关闭(off)、非常低(verylow)、中等(moderate)和非常高(veryhigh),其他计划参数设置保持一致,使用射野剂量系统(PD)验证剂量传输的准确性。主要评价指标包括剂量体积直方图(DVH)、Paddick适形指数(PCI)、梯度指数(GI)、均质性指数(HI)、剂量率(DoseRate)、机架转速(GantrySpeed)、机器跳数(MUs)、每角度机器跳数(MU/deg)和Gamma通过率,采用单因素方差分析和Kruskal-Wallis秩和检验检测4组ASC计划之间各项统计指标的差异。结果:4组ASC计划间除计划靶区平均剂量(PTV D_med)差异有统计学意义(F=3.243,P=0.027)外,其他DVH、PCI、GI和HI指标差异均无统计学意义。机器传输能力中ASC为very low、moderate和very high的MUs较off分别下降14.4%、20.9%和29.6%。4组计划间DoseRate、MU/deg和MUs差异有统计学意义(x²=16.621,x²=16.007,x²=15.877;P=0.001)。剂量传输准确性中4组计划间3%/3 mm和2%/2 mm的Gamma通过率差异均无统计学意义。结论:计划设计过程中需考虑ASC对各项计划指标的影响,应根据计划的复杂性和临床需要调整ASC的等级。     

The relationship of anterior cruciate ligament injuries with MRI based calculation of femoral notch width,notch width index,notch shape - A randomized control study

BackgroundACL injuries are infamously known for disability in young adults and require surgical reconstruction. The need of time is to predict predisposing factors and prevent ACL injuries.The incidence of ACL injuries has been associated with various factors related to the morphology of distal femur and proximal tibia.Hence, purpose of this study was to assess the relationship of morphology of distal femur by assessing Notch Width(NW), Notch Width Index (NWI), and Notch shape calculated preoperatively on MRI in association with an ACL tear.MethodsThe following randomized control study had 60 patients enrolled with non contact injury to knee who were equally divided into 2 groups i.e. ACL injury group and control group. ACL group had patients who had MRI proven ACL tear along with clinical findings suggestive of ACL tear whereas control contained patients with intact ACL. Demographic data was collected and NW, NWI and Notch shape were determined on coronal sections of MRI sequences.ResultsPositive correlation of ACL tear was seen with NW, BCW, NWI, NWP, and NWJ. Smaller Notch Width showed higher incidence of ACL tear (p = 0.019). The mean NWI in the injured and control knee is 0.31 ± 0.01 and 0.27 ± 0.01 respectively and was statistically significant(p < 0.001). A shaped Notch (60%) was commonly seen in ACL tear group and U shaped notch (73.3%) was commonly seen in control group.We found the cut off value for the prediction of ACL tear of NWI was 0.29 with a sensitivity of 90% and specificity of 86.7%.ConclusionACL injuries in the given population have shown higher incidence with narrow femoral intercondylar notch, smaller notch width index, ‘A’ shaped femoral notch. If any of the above findings are present in the MRI, its important to counsel the subjects about the increased risk of ACL injuries in them and take preventive measures.