Aircraft noise annoyance at three joint air carrier and general aviation airports

The results of social surveys conducted near three airports that support both general aviation and scheduled air carrier operations are presented and discussed. Inferences supported by these data include: The nature of noise exposure and community reaction at smaller airports may differ from that at larger airports; survey techniques are capable of identifying changes in annoyance associated with numerically small changes in noise exposure; changes in the prevalence of annoyance are causally produced by changes in noise exposure; and changes in annoyance associated with changes in exposure vary with time.     

On the evaluation of measurements of small changes in electric resistance

The measurement of small changes in resistance, caused in metal wires by non-equilibrium point defects, meets with many difficulties caused inter alia by changes in temperature, instability of the voltage source and irreversible changes in the electric resistance due to the thermal treatment of the samples. In the first part of the paper, dealing with the d-c bridge method of measurement, the conditions under which the relations given in the literature can be used for calculating small changes in resistance are quantitatively determined on the basis of a detailed analysis of such relations. The second part describes a method of measurement permitting the elimination of irreversible changes in the resistance of thermally treated samples and relations are derived for calculating reversible changes.     

青藏高原东北部闪电M变化多参量观测

利用闪电光通道高速摄像、 地面电场变化和峰值辐射强度同步资料, 对比分析了负地闪连续电流阶段和人工触发闪电放电过程中M变化特征. 结果表明, 通道亮度资料能够辅助地面电场波形来准确判断是否为真实的M过程. 在经典M变化产生前及其过程中会产生很多快速电场变化MP(称为预M变化)变化, 大量MP促成了M变化. MP变化和K变化在脉冲特征上没有太多差别, 产生的物理机制是相似的. MP变化是连续电流阶段快速电场变化, 是击穿过程引起的电荷快速流动的结果, 并伴有通道突然增亮和高强度辐射. M变化脉冲波形多数为单极性, 有正有负, 少数呈现不规则变化, 持续时间在0.1 ms之内.而经典M变化的U 形结构只适用于近闪, 波形是静电场所致, 持续时间约0.2–0.8 ms. MP和K变化都是击穿所致, 只是MP变化有电荷流入原回击通道, 而K变化没有. 关键词： 青藏高原 M变化')" href="#">M变化 MP变化')" href="#">MP变化 K变化')" href="#">K变化     

Hyperthermia induces T1 relaxation and blood flow changes in tumors. A MRI thermometry study in vivo

Regional hyperthermia in combination with chemotherapy and/or radiotherapy has proven to be an effective treatment concept for locally advanced deep-seated tumors. Simultaneous MR-imaging could be a promising approach for therapy optimization. Purpose of this study was the in vivo investigation of temperature induced longitudinal relaxation time (T(1)) and blood flow changes in a tumor model. Using a 1.5 Tesla MR system, the T(1) sensitivity on temperature and the onset of tissue changes at temperatures >44 degrees C were investigated in muscle samples. Also, fourteen Syrian Golden Hamsters with amelanotic melanoma A-MEL-3 were examined during heating of the tumors. Temperature induced blood flow and T(1) changes were determined continuously during hyperthermia. Changes of T(1) correlated linearly with temperature over a wide range (27-44 degrees C) in the tissue sample. Tissue changes became notable above 44 degrees C. In the tumor model, relative changes of T(1) (unlike blood flow) showed linear correlation with temperature over the entire range of hyperthermia relevant temperatures (32-44 degrees C). For a low thermal dose, T(1) allows the assessment of temperature changes in tumors in vivo. At higher thermal doses, in addition to temperature changes, T(1) also shows tissue changes. Both temperature and tissue changes supply important information for hyperthermia.     

Treatment-related central nervous system toxicity: MR imaging evaluation with CT and clinical correlation

Thirteen patients with abnormal brain MR scans attributable to treatment-induced injury were retrospectively reviewed. All patients were treated with radiation therapy and 62% received chemotherapy. Five patients were graded as having severe white matter (WM) changes, four had moderate WM changes, and four had mild WM changes. CT was generally equivalent to MR in evaluation of severe and moderate WM abnormalities, whereas MR was superior to CT in detection of mild WM abnormalities. In general, the severity of changes depicted by MR/CT correlated with the extent of neurologic dysfunction. The most severe changes were seen in those patients treated with combination irradiation and chemotherapy.     

Phospholipid-stabilized microbubbles: Influence of shell chemistry on cavitation threshold and binding to giant uni-lamellar vesicles

We demonstrate the feasibility of covalently linking a single microbubble to a single, giant uni-lamellar vesicle (GUV). Such a combination of GUV plus microbubble might prove useful as a new drug delivery vehicle involving microbubble cavitation-induced sonoporation of the vesicle bilayer as a release mechanism. We therefore applied the well known methodology of passive cavitation detection to measure the influence of lipid shell chemistry on inertial cavitation thresholds for externally added microbubbles. We find that cavitation threshold changes significantly with changes in either molecular weight or mole fraction of poly(ethylene glycol), historically used to impede gas dissolution and microbubble coalescence. We attribute changes in cavitation threshold to changes in microbubble resonance frequency resulting from changes in microbubble shell bending elasticity. To further demonstrate the influence of shell chemistry on microbubble behavior, we describe how several common bubble phenomena - and some new - respond to changes in lipid chain length.     

First order phase change detection using planar waveguide Bragg grating refractometer

Solid-to-liquid and gas-to-liquid phase changes in water and ordered-to-isotropic phase changes in a nematic liquid crystal are detected with an optical sensor. A planar Bragg grating defined purely by refractive index modulation is covered with a water or liquid crystal overcladding and the temperature is controlled to trigger phase changes. Measurement of the Bragg wavelength allows changes of effective refractive index to be detected and discontinuities in behaviour caused by phase transitions can be clearly identified.     

A multimodality investigation of cerebral hemodynamics and autoregulation in pharmacological MRI

Pharmacological MRI (phMRI) methods have been widely applied to assess the central hemodynamic response to pharmacological intervention as a surrogate for changes in the underlying neuronal activity. However, many psychoactive drugs can also affect cardiovascular parameters, including arterial blood pressure (BP). Abrupt changes in BP or the anesthetic agents used in preclinical phMRI may impair cerebral blood flow (CBF) autoregulation mechanisms, potentially introducing confounds in the phMRI response. Moreover, relative cerebral blood volume (rCBV), often measured in small-animal phMRI studies, may be sensitive to BP changes even in the presence of intact autoregulation. We applied laser Doppler flowmetry and MRI to measure changes in CBF and microvascular CBV induced by increasing doses of intravenous norepinephrine (NE) challenge in the halothane-anesthetized rat. NE is a potent vasopressor that does not cross the blood-brain barrier and mimics the rapid BP changes typically observed with acute drug challenges. We found that CBF autoregulation was maintained over a BP range of 60-120 mmHg. Under these conditions, no significant central rCBV responses were observed, suggesting that microvascular rCBV changes in response to abrupt changes in perfusion pressure are negligible within the autoregulatory range. Larger BP responses were accompanied by significant changes in both CBV and CBF that might confound the interpretation of phMRI results.     

Structural changes and volatility transmission in crude oil markets

This study examines the influence of structural changes in volatility on the transmission of information in two crude oil prices. In an effort to assess the impact of these structural changes, we first identify the time points at which structural changes in volatility occurred using the ICSS algorithm, and then incorporate this information into our volatility modeling. From the estimation results using a bi-variate GARCH framework with and without structural change dummies, we find that the degree of persistence of volatility can be reduced via the incorporation of these structural changes in the volatility model. In this direction, we conclude that ignoring structural changes may distort the direction of information inflow and volatility transmission between crude oil markets.     

埋入式光纤法布里—珀罗温度和应变传感器模型研究

研究了埋入式内置和外置型法布里－珀罗光纤传感器模型，这一框蒋 传感器中应变和温度的变化同反射光强联系起来，其中；子模型Ⅰ建立了传感器内的温度与应变同传感器长度变化及传感器光学性质变化的函数关系；子模型Ⅱ建立了传感器长度和光学性质的变化同反射光强变化的函数关系。     

The effect of dexamethasone on tissue water distribution and proton relaxation in Panc02 tumors

The present experiments were conducted to determine the effects of dexamethasone mediated changes in tumor water distribution on proton relaxation times (T1, T2) in a murine pancreatic adenocarcinoma (Panc02). Spin lattice (T1) and spin-spin (T2) relaxation times were determined by ex vivo methods (10MHz) and by in vivo imaging techniques (6.25 MHz) at various intervals after single or multiple dexamethasone treatments. In complementary studies, dexamethasone mediated changes in tumor capillary permeability, tumor water distribution, relative tumor blood flow and tumor cell proliferation were also determined.

Proton spin lattice (T1) and spin-spin (T2 relaxation times for Panc02 tumors shortened within two hours of a single dexamethasone treatment. The time course and magnitude of this response was dexamethasone dose dependent. The time dependent changes in T1 and T2 after dexamethasone were similar at 10 MHz (ex vivo) and 6.25 MHz (in vivo imaging). Although dexamethasone produced little or no change in total tumor water content and tumor cell proliferation, transient changes in the physiologic distribution of tumor water were clearly demonstrated.

The data supports the idea that dexamethasone induced changes in the distribution of tumor water were mediated by changes in capillary permeability and tumor blood flow. These physiologic responses produced serial changes in tumor extracellular extravascular water content that were consistent with the observed changes in tumor T1 and T2. The results from these experiments might imply that therapy associated changes in tumor proton relaxation times may not only reflect changes in tissue water content, but may also reflect physiologic responses which alter the distribution of tissue water and solute.     

拉曼光谱技术在脂质过氧化反应中的应用

本实验以亚油酸为材料,分别采用过氧化产物检测法和拉曼光谱技术对亚油酸的自氧化过程进行监测,从氧化反应的中间产物和底物的结构变化两个角度,对亚油酸的自氧化过程进行分析。为不饱和脂肪酸的过氧化机理研究提供实验证据。结果表明:拉曼光谱技术能够用来研究单分子物质的结构变化,随着自氧化过程的进行,亚油酸的拉曼光谱在谱型和峰强方面都有所变化,能够反映分子内部结构的变化。其时间效应与采用TBA和共轭二烯法测定时的时间效应基本一致。     

Theory of chemisorption of hydrogen on transition metals and their alloys

A theoretical discussion is given of the changes in the heat of chemisorption of a hydrogen atom upon alloying a group-VIII metal with a group-IB metal. The emphasis is on two concepts: the ensemble effect and the ligand effect. The ensemble effect ascribes the changes in the heat of chemisorption primarily to changes in the geometry of the adsorption complex, whereas the ligand effect also takes into account changes in bond strength due to a different intrinsic activity of the bonding metal atoms.     

利用酪氨酸残基的共振瑞利散射研究溶液中蛋白质构象

基于酪氨酸残基K带激发峰在较高浓度的蛋白质溶液中表现出特征散射峰,通过Δλ＝0同步荧光扫描识别,建立用荧光分光光度法测定酪氨残基K带的共振散射峰强度及其波长位移来推测溶液中蛋白质构象变化的新方法。方法不受蛋白质色氨酸残基的干扰,图谱简单明了直观。文章叙述了方法建立的实验基础,并用构建的方法研究了盐效应、酸碱性效应对蛋白质构象变化的影响,最后通过测定不同温度下酶活性的实验验证了方法对温度影响酶蛋白质构象变化的分析的正确性。     

Laser heterodyne measurements of photo-induced refractive-index changes in amorphous As-S films

A differential-type heterodyne interferometer has been successfully utilized for studying the refractive-index changes in As-S films under illumination. The measuring system can detect phase changes down to 1° in angle in accuracy and sensitivity. It is confirmed that illumination of the films involves two distinct factors: a thermal and an optical one. The index changes are caused only by the optical effect. The time-dependent characteristics of the index changes are explained to be closely related to the photo-darkening effect.     

Changes of summating potentials and morphology in theguinea pig cochlea during anoxia

I.IntroductionThesummatingpotcntia1s(SPs)rcprcscntsaspccificbioe1cctronphenomenonofthecoch1ea.C1inica1lythedominant-SPisnowtakenasasignofrecruitmcnt.However,themechanismofrecruitn1cnt,exccptinMcnicrcdiscase,isnotentireIyunderstood.Thedynamicchangcsinamp1itudcandpolarityofSP,lnrclationtothethrcsho1dshiftofcompoundactionpotential(CAP),SPandcndocochlcapotcntial(EP)inthescalcmcdiawcrcexaminedatonehmewithsing1cmicropipctduringandaftcranoxia.Also,themorpho1ogicchangesinthein-nerhaircc11s(IHC…     

Topology and numerical simulation of phase separation in sodium silicate glasses

Liquid/liquid phase separation in glasses may lead to heterogeneities in the nanometer scale. The droplet phase can be nucleated from a homogeneous liquid. The chemical composition of the nanoscale phase separation changes with temperature in contrast to the nanocrystallization. The understanding of topological changes in the glass networks is of importance for the changes in viscosity and the microscopic changes in the growth rate during the course of the phase separation process. This work considers a glass system in which one of the separated phases is much more rigid than the other and the formed new phase possesses a lower viscosity in comparison to the matrix phase. The chemical composition of the matrix changes only in a thin layer around the growing droplets. A shell with increased rigidity is formed which decelerates the growth by encapsulation.     

Modeling sudden volatility changes: Evidence from Japanese and Korean stock markets

In this study, we have investigated sudden changes in volatility and re-examined the persistence of volatility in Japanese and Korean stock markets during 1986-2008. Using the iterated cumulative sums of squares (ICSS) algorithm, we have determined that the identification of sudden changes is generally associated with global financial and political events. We have also demonstrated that controlling sudden changes effectively reduces the persistence of volatility or long memory and that incorporating information regarding sudden changes in variance improves the accuracy of estimating volatility dynamics and forecasting future volatility for researchers and investors.     

Sodium and proton diffusion MRI as biomarkers for early therapeutic response in subcutaneous tumors

The ability to quantitate early effects of tumor therapeutic response using noninvasive imaging would have a major impact in clinical oncology. One area of active research interest is the ability to use MR techniques to detect subtle changes in tumor cellular density. In this study, sodium and proton diffusion MRI were compared for their ability to detect early cellular changes in tumors treated with a cytotoxic chemotherapy. Subcutaneous 9L gliosarcomas were treated with a single dose of 1,3-bis(2-chloroethyl)-1-nitrosourea. Both sodium and diffusion imaging modalities were able to detect changes in tumor cellularity as early as 2 days after treatment, which continued to evolve as increased signal intensities reached a maximum approximately 8 days posttreatment. Early changes in tumor sodium and apparent diffusion coefficient values were predictive of subsequent tumor shrinkage, which occurred approximately 10 days later. Overall, therapeutical induced changes in sodium and diffusion values were found to have similar dynamic and spatial changes. These findings suggest that these imaging modalities detected similar early cellular changes after treatment. The results of this study support the continued clinical testing of diffusion MRI for evaluation of early tumor treatment response and demonstrate the complementary insights of sodium MRI for oncology applications.     

In vivo non-invasive studies on the human lens.

Progress in biophysical technology now permits us to monitor aging and precataractous changes in the human ocular lens in vivo as well as in vitro. We are employing two noninvasive techniques to measure changes in lens fluorescence and in one lens water compartment (T2) utilizing Scheimpflug lens fluorescence densitography and magnetic resonance imaging. These studies demonstrate age-related changes in the normal lens as reflected by enhanced fluorescence and longer T2 values. Precataractous changes can also be detected with this approach.