Effects of Low Dose Radiation on Tumor Apoptosis, Cell Cycle and Apoptosis-Related Protein Bcl-2 in Tumor-Bearing Mice

To study the effects of low dose radiation (LDR) on tumor apoptosis, cellcycle progression and changes of apoptosis-related protein Bcl-2 in tumor-bearing mice. Methods:Male mice of Kunming strain were implanted subcutaneously with S180 sarcoma cells in the left inguenas an in situ experimental animal model. Seven days later, the mice were subjected to 75 mGywhole-body γ-irradiation. At 24 and 48 h after the irradiation, all mice were sacrificed. The tumorsizes were measured, and tumor cell apoptosis and cell cycle progression were analyzed by flowcytometry. The expression of apoptosis-related protein Bcl-2 and the apoptotic rate of tumor cellswere observed by immunohistochemistry and electron microscopy. Results: Tumors grew significantlyslower after LDR (P 【 0.05). The tumor cells were arrested in G1 phrase and the expression of Bcl-2protein decreased at 24 h. Apoptotic rate of tumor cells was increased significantly at 48 h afterLDR (P 【 0.01). Conclusion: LDR could cause a G1-phase arrest and increase the apoptosis of tumorcells through the low level of apoptosis-related protein bcl-2 in the tumor-bearing mice. Theorganized immune function and anti-tumor ability are markedly increased after LDR. Our studyprovides practical evidence of clinical application to cancer treatment.

6LoWPAN中基于Mesh-under的备用缓存机制

在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。

H_(2)S/CO_(2)共存环境中X65钢点腐蚀形成机理及预测方法

碳钢管材广泛应用于油气生产系统,在含CO_(2)、H_(2)S、氯离子等多种腐蚀介质共存的多相流环境中,容易发生腐蚀穿孔泄漏,可能造成管道和设备的失效,进而带来安全隐患和经济损失。目前针对H_(2)S/CO_(2)共存环境下金属腐蚀的研究主要集中在较高H_(2)S分压下,多种形式FeS产物的生成规律、产物膜保护特性和点蚀形成机理,很少研究极微量H_(2)S诱发点腐蚀的可能性和发生条件。为此,以X65钢为例,利用大型H_(2)S多相流腐蚀环路实验系统完成了4组测试实验和2组验证实验,研究了40℃、恒定CO_(2)分压环境下,不同H_(2)S分压对低碳钢点腐蚀行为的影响规律,并提出了一种基于热力学理论的预测方法。研究结果表明:①当H_(2)S分压高于50 Pa时,X65钢的腐蚀速率低且表现为全面腐蚀;而当H_(2)S分压低于24 Pa时,随着H_(2)S分压的逐步降低,X65钢的点腐蚀加剧,H_(2)S为2.4 Pa时的点腐蚀速率超过11 mm/a。②当H_(2)S分压极低且马基诺型FeS的过饱和度低于1时,快速形成的FeS膜不能完整覆盖金属表面,暴露表面会在电偶腐蚀的作用下,被饱和CO_(2)溶液快速腐蚀,最终导致低碳钢发生局部点腐蚀。③建立不同H_(2)S分压下低碳钢表面马基诺型FeS过饱和度边界控制曲线,可以准确预测不同条件下碳钢的点腐蚀行为。结论认为,在相关行业标准规定的H_(2)S分压下限以内,H_(2)S/CO_(2)共存环境中极微量的H_(2)S仍然可能会诱发碳钢发生点腐蚀,该认识对于H_(2)S/CO_(2)共存环境下油气管道的局部点腐蚀预测和防腐防护研发具有重要理论和现实意义。

Henry's Law constant for phosphine in seawater:determination and assessment of influencing factors

The Henry＇s Law constant （k） for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature （approximately 23℃）. This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry＇s Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.

Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx （OH and HO2） radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry＇s law constant （KH）, significantly influences its role in atmospheric processes. Large discrepancies between the KH values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of （0.960 ± 0.013） atm （1 atm = 1.01325 × 10^5 Pa）. The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van＇t Hoff equation form, expressed as lnKH = a/T - b, and a = -△H/R, where KH is in M/atm （M is mol/L）, T is in degrees Kelvin, R is the ideal gas constant, and AH is the standard heat of solution. For acidity dependence, results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level （from pH 7 to pH 1）. Combining the dependence of both temperature and acidity, the obtained a and b were 7024 ± 138 and 11.97 ± 0.48, respectively, AH was （58.40 ± 1.15） kJ/（K.mol）, and the uncertainties represent σ. Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.

A New Labdane Diterpenoid from the Bark of Larix olgensis Henry var. koreana Nakai

A new diterpenoid was isolated from the bark of Larix olgensis Henry var. koreana Nakai. Its structure was elucidated as 5S, 9S, 10R-labda-8 (17), 13-diene-6a, 15-diol l by spectroscopic methods.

血清S-100B蛋白、可溶性凝集素样氧化低密度脂蛋白受体-1、胶质纤维酸性蛋白检测在新生儿缺血缺氧性脑病病情严重程度中的诊断价值

目的:探讨血清S-100B蛋白、可溶性凝集素样氧化低密度脂蛋白受体-1(sLOX-1)、胶质纤维酸性蛋白(GFAP)与新生儿缺血缺氧性脑病(HIE)病情严重程度的关系。方法:选择80例HIE患儿作为观察组,另选择90例健康新生儿作为对照组,收集所有患儿一般资料,并检测两组患儿血清S-100B蛋白、sLOX-1、GFAP水平,分析HIE患儿血清S-100B蛋白、sLOX-1、GFAP与病情严重程度的相关性及预后不良的影响因素。结果:对照组血清S-100B蛋白、sLOX-1、GFAP水平低于观察组(均P<0.05)。重度组血清S-100B蛋白、sLOX-1、GFAP水平高于中度组、轻度组和对照组(均P<0.05)。Pearson相关分析显示,疾病严重程度与HIE患儿血清S-100B蛋白、sLOX-1、GFAP水平呈正相关(均P<0.001)。随访预后良好患儿59例,预后不良21例,经多因素Logistic回归分析显示,产程异常、病情重度、S-100B蛋白、sLOX-1、GFAP为影响HIE患儿预后的危险因素(均P<0.05)。结论:HIE患儿病情严重程度和预后与血清S-100B蛋白、sLOX-1、GFAP水平有关,监测其水平变化有利于临床早期完善干预方案改善预后。

A new bionic MAV's flapping motion based on fruit fly hovering at low Reynolds number

On the basis of the studies on the high unsteady aerodynamic mechanisms of the fruit fly hovering the aerodynamic advantages and disadvantages of the fruit fly flapping motion were analyzed. A new bionic flapping motion was proposed to weaken the disadvantages and maintain the advantages, it may be used in the designing and manufacturing of the micro air vehicles （MAV＇s）. The translation of the new bionic flapping motion is the same as that of fruit fly flapping motion. However, the rotation of the new bionic flapping motion is different. It is not a pitching-up rotation as the fruit fly flapping motion, but a pitching-down rota- tion at the beginning and the end of a stroke. The numerical method of 3rd-order Roe scheme developed by Rogers was used to study these questions. The correctness of the numerical method and the computational program was justified by comparing the present CFD results of the fruit fly flapping motion in three modes, i.e., the advanced mode, the symmetrical mode and the delayed mode, with Dickinson＇s experimental results. They agreed with each other very well. Subsequently, the aerodynamic characteristics of the new bionic flapping motion in three modes were also numerically simulated, and were compared with those of the fruit fly flap- ping. The conclusions could be drawn that the high unsteady lift mechanism of the fruit fly hovering is also effectively utilized by this new bionic flapping. Compared with the fruit fly flapping, the unsteady drag of the new flapping decreases very much and the ratio of lift to drag increases greatly. And the great discrepancies among the mean lifts of three flapping modes of the fruit fly hovering are effectively smoothed in the new flapping. On the other hand, this new bionic flapping motion should be realized more easily. Finally, it must be pointed out that the above conclusions were just drawn for the hovering flapping motion. And the aerodynamic characteristics of the new bionic flapping motion in forward flight are going to be studied in the next step.

Prediction of Henry's constant in polymer solutions using PCOR equation of state coupled with an activity coefficient model

In this paper,the polymer chain of rotator(PCOR) equation of state(EOS) was used together with an EOS/G^E mixing rule(MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to extend the capability and improve the accuracy of the PCOR EOS for predicting the Henry's constant of solutions containing polymers.The results of the proposed method compared with two equation of state(van der Waals and GC-Flory) and three activity coefficient models(UNIFAC,UNIFAC-FV and Entropic-FV) indicated that the PCOR EOS/Wilson's equation provided more accurate results.The interaction parameters of Wilson's equation were fitted with Henry's constant experimental data and the property parameters of PCOR,a and b,were fitted with experimental volume data(Tait equation).As a result,the present work provided a simple and useful model for prediction of Henry's constant for polymer solutions.

Low grade dysplasia in Barrett's esophagus:Should we worry?

The optimal management for low-grade dysplasia(LGD)in Barrett’s esophagus is unclear.In this article the importance of LGD is discussed,including the significant risk of progression to esophageal adenocarcinoma.Endoscopic surveillance is a management option but is plagued by sampling error and issues of suboptimal endoscopy.Furthermore endoscopic surveillance has not been demonstrated to be cost-effective or to reduce cancer mortality.The emergence of endoluminal therapy over the past decade has resulted in a paradigm shift in the management of LGD.Ablative therapy,including radiofrequency ablation,has demonstrated promising results in the management of LGD with regards to safety,cost-effectiveness,durability and reduction in cancer risk.It is,however,vital that a shareddecision making process occurs between the physician and the patient as to the preferred management of LGD.As such the management of LGD should be"individualised."

Logical hypothesis:Low FODMAP diet to prevent diverticulitis

Despite little evidence for the therapeutic benefits of a high-fiber diet for diverticulitis, it is commonly recommended as part of the clinical management. The ongoing uncertainty of the cause(s) of diverticulitis confounds attempts to determine the validity of this therapy. However, the features of a high-fiber diet represent a logical contradiction for colon diverticulitis. Considering that Bernoulli&rsquo;s principle, by which enlarged diameter of the lumen leads to increased pressure and decreased fluid velocity, might contribute to development of the diverticulum. Thus, theoretically, prevention of high pressure in the colon would be important and adoption of a low FODMAP diet (consisting of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) may help prevent recurrence of diverticulitis.

Study on the Antitumor Effects of Low-energy Laser Irradiation Combined with Cyclophosphamide

Systematic experiments about the antitumor effects of low energy laser irradiation combined with the traditional antitumor medicine of cyclophosphamide were conducted using the experimental model of mouse S180 ascites sarcoma.The three groups of tumor bearing mice were irradiated upon the inner corners with the dosages of 11 00,14 67 and 22 00 J·cm -2 LELI respectively,and injected with CYT intraperitoneally to observe the changes of the survival time,the ascites growth speed,and the kinetic changes of immune functions.The survival times of the three groups of CYT/LELI combination were obviously longer than those of the tumor and CYT control groups.Correspondingly,the amounts of ascites,tumor cells densities and total tumor cells in CYT/LELI groups decreased significantly,while the death ratio of the tumor cells increased.Comparatively,the group of 22 00 J·cm -2 LELI combined with CYT showed the most ideal antitumor effects,and the life prolongation ratio was up to 53 20%.

Modulation of MMP-2 and TIMP-2 by low dose radiation in mice bearing S180 sarcoma

Objective To investigate the inhibition of low dose radiation （LDR） on S180 sarcomas and its modulation of MMP-2 and TIMP-2 in mice. Methods $180 subcutaneously implanted tumor model mice were randomly divided into two groups： control （N） and low dose radiation （LDR） groups. N mice were sacrificed after 12 h, whereas LDR mice were sacrificed after 12 （LDR-12 h）, 24 （LDR-24 h）, 48 （LDR-48 h）, and 72 （LDR-72 h） h. Thereafter, we measured the tumor volumes. Histopathology was performed, and P-V immunohistochemistry was applied to assess MMP-2 and TIMP-2 expression. Results Compared with the control group, the tumor growth was significantly inhibited in the LDR groups （P 〈 0.05）. MMP-2 expression was considerably reduced in LDR-24h （P 〈 0.05） and LDR-48h （P 〈 0.05）, whereas the change of TIMP-2 was not obvious in the LDR groups （P 〉 0.05） in contrast to that of the control group. Conclusion LDR can effectively suppress the growth of S180 implanted tumors by reducing MMP-2, which is associated with invasion and metastasis.

Saturation evaluation of microporous low resistivity carbonate oil pays in Rub Al Khali Basin in the Middle East

To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock conductivity during displacement were analyzed by displacement resistivity experiments simulating the process of reservoir formation and production, together with the data from thin sections, mercury injection and nuclear magnetic resonance experiments. In combination with geological understandings, the genetic mechanisms of LRPs were revealed, then the saturation interpretation model was selected, the variation laws and distribution range of the model parameters were defined, and finally an updated comprehensive saturation interpretation technique for the LRPs has been proposed. In the study area, the LRPs have resistivity values of less than 1 Ω·m, similar to or even slightly lower than that of the water layers. Geological research reveals that the LRPs were developed in low-energy depositional environment and their reservoir spaces are controlled by micro-scale pore throats, with an average radius of less than 0.7 μm, so they are typical microporous LRPs. Different from LRPs of sandstone and mudstone, they have less tortuous conductive paths than conventional reservoirs, and thus lower resistivity value under the same saturation. Archie’s formula is applicable to the saturation interpretation of LRPs with a cementation index value of 1.77-1.93 and a saturation index value of 1.82-2.03 that are 0.2-0.4 lower than conventional reservoirs respectively. By using interpretation parameters determined by classification statistics of petrophysical groups(PGs), oil saturations of the LRPs were calculated at bout 30%-50%,15% higher than the results by conventional methods, and basically consistent with the data of Dean Stark, RST, oil testing and production. The 15 wells of oil testing and production proved that the coincidence rate of saturation interpretation is over 90%and the feasibility of this method has been further verified.

Henry David Thoreau's Spiritual World

Henry David Thoreau was wholeheartedly in love with nature and he devoted almost all his life time to observation,appreciation and study of nature.Thus he formed a deep understanding of nature.In 1845,Thoreau began a two-year and twomonth residence at Walden Pond.His life was lonely but full of fragrance.He wanted to live meaningfully,confront the essential facts of life and live a simple life.Based on the review of the literature related to this topic,this paper aims to study Henry David Thoreau’s spiritual world,especially reflected in his famous book—Walden.

Free-radical scavenging properties of low molecular weight peptide(s) isolated from S1 cultivar of mulberry leaves and their impact on Bombyx mori(L.)(Bombycidae)

The mulberry leaves have been considered as a sole food source for silkworm, Bombyx mori （L.）. In present work an attempt was made to investigate the role of low molecular weight peptide（s） isolated from mulberry leaves on silkworm rearing. Also we have tried to find out the role of free-radical scavenging activities of isolated peptide（s） on silkworm growth. Larval growth rate was found effective under the influence of peptide（s）. Consumption rate of larvae after peptide（s） treatment on mulberry leaves was significantly enhanced over control. High antioxidant activity was found in Low molecular weight peptide（s） which have an effect on silkworm.

Behaviour of Rare Earths in Low Sulphur Steel

In steels 16Mn and X60 with low S content (0. 003～0. 005%), rare earth metals (REM) still show ef- fects on purifying the molten steel and controlling the sulphide morphology. The optimum ratio of RE/S is about 2. 0, which causes lower content of oxygen and inclusions and higher impact toughness. The amount of REM in solid solution in the steel was determined by means of inductive coupling plasma (ICP) spectroscopy. The dissolved REM in low S steel could decrease the propor- tion of pearlite and increase the strength of the steel.

Applicability of P/S amplitude ratios for the discrimination of low magnitude seismic events

Applicability of regional P/S amplitude ratios for the discrimination of low-magnitude seismic events was tested and proved using earthquakes and explosions in Central Asia. Results obtained show that regional P/S amplitude ratios which may discriminate medium or large magnitude events well, are also applicable to low magnitude events Their performances for low magnitude events are almost as good as that for medium or large events. Statistical comparisons based on 25 P/S discriminate from the four seismic stations WMQ, BLK, MUL and MAK showed that the average misclassification rate for low-magnitude seismic events averagely was only 2 percent higher than that for medium and large magnitude seismic events.

TRUE KINGLY HONOUR IN SHAKESPEARE′S HENRY IV PART I

Honour, one of the eternal themes in Shakespeare, is again in the spotlightin Henry IV Part I. In this play, the rivalry between Prince Hal and Hotspuremerges actually out of their cravings for the title of royal honour and valour.Hotspur appears to be formidable, courageous and energetic. He is exactly

Determination of the Henry’s Law Constant of Hexane in High-Viscosity Polymer Systems

The Henry’s law constant of volatiles in polymer systems is a crucial parameter reflecting the gas-liquid equilibrium,which is very important for devolatilization.In this research,polyolefin elastomer(POE)-cyclohexane and polydimethylsiloxane(PDMS)-hexane systems were studied,and the Henry’s law constant was obtained by measuring the gas phase equilibrium partial pressure when polymer solutions containing different mass fractions of volatiles reached a saturated state.The effects of temperature,type of volatiles,and polymer viscosity on the gas phase equilibrium partial pressure and Henry’s law constant of the volatiles were investigated.The results indicate that,with the increase of temperature and polymer viscosity,the gas phase equilibrium partial pressure and Henry’s law constant of volatiles increase.As temperature increases,the solubility of gas in liquid decreases.The relationship between the Henry’s law constant and temperature is consistent with the Arrhenius law.In the PDMS-hexane system,the gas phase equilibrium partial pressure and Henry’s law constant of n-hexane are higher than those of cyclohexane.The obtained Henry’s law constants can be used as a reference for perfecting the devolatilization process and improving the devolatilization effect.