Inhibitory effect of 5-FU loaded ultrasound microbubbles on tumor growth and angiogenesis

The anti-neovascularization treatment is one of the effective strategies for tumor molecular target therapy. At present, the target and effect of the anti-neovascularization treatment is limited, and it is urgent to establish a new vascular targeting strategy to effectively treat tumors. In this work, we used high intensity focused ultrasound (HIFU) combined with targeted microbubbles to establish a molecular targeted ultrasound response microbubble for neovascular cells. Furthermore, the effects of drug loaded microbubbles on neovascularization and tumor cells were studied. The tumor vascular targeted and ultrasound-responsive microbubbles of 5-FU@DLL4-MBs were prepared by the thin-film dispersion method. The size and zeta potential of 5-FU@DLL4-MBs was about 1248 nm and −9.1 mV. 5-FU@DLL4-MBs released 5-FU showed an ultrasound-responsive manner, and had better vascular-targeting ability. Furthermore, the 5-FU@DLL4-MBs showed the strongest cytotoxic effect on HUVECs or HepG-2 cells and can be effectively internalized into the HUVECs cells. Thus, 5-FU@DLL4-MBs combined with HIFU can be considered as a potential method for antitumor angiogenesis in the future.     

HIFU治疗下生物体焦域温度分布的研究与应用

高强度聚焦超声(HIFU)为无创治疗肿瘤带来了新的途径,本文对HIFU治疗下生物体焦域热分布和热传导模型的理论进行了初步的介绍,并在理论的指导下进行不同治疗剂量的实验研究,结果表明组织内具有热波传热效应,治疗时可以根据治疗剂量的需要选取不同的参数,以达到最佳治疗效果。     

Echinococcus granulosus: Protoscolicidal effect of high intensity focused ultrasound

High intensity focused ultrasound (HIFU) is a new non-invasive technique which can cause cell death and tissue necrosis by focusing high-energy ultrasonic waves on a single location. The aim of our work is to investigate the damaging effect of HIFU on Echinococcus granulosus protoscolices, as well as its inhibitory effect on growth of hydatid cysts derived from protoscolices. The damaging effect of HIFU on protoscolices was investigated by following parasite mortality after irradiation, while the inhibitory effect was investigated by infection experiments in vivo. The results demonstrated that HIFU was able to damage protoscolices and the protoscolicidal effect was dose-dependent and showed late-onset. The growth of protoscolices that survived the exposure to HIFU was obviously suppressed in vitro, and the mean weight of hydatid cysts resulting from such protoscolices in the experimental group was less than that in controls. Evidences including the protoscolicidal effect, fragmentized protoscolices and low post exposure temperatures, suggest that cavitation may contribute to the protoscolicidal effect of HIFU. In addition, the structure of the germinal membrane in cysts developing from the irradiated protoscolices was not as normal or intact as that from non-irradiated ones, and morphological changes related to degeneration were observed, suggesting that HIFU could prevent protoscolices from developing normal germinal membrane and consequently stop the proliferation of secondary hydatid cysts. HIFU demonstrated damaging effect on protoscolices, inhibited the growth of protoscolices in vitro and in vivo, and could be a possible therapeutic option for cystic echinococcosis.     

Temperature effect on the ciliary beat frequency of human nasal and tracheal ciliated cells.

Even though all human respiratory cilia are similar in structure, they experience a wide range of temperatures between the initial part of the nasal fossae which behave as heat exchangers and the inferior part of the trachea, particularly when we inhale exceedingly cold or hot air. The ciliary beat frequency of ciliated cells from human nasal mucosa and from bronchial mucosa averages 8 Hz when measured at room temperature. In the present study we compared the ciliary beat frequency of human cells from nasal and tracheal mucosa brushings at different temperatures from 5 degrees C to 50 degrees C using two different techniques, ex vivo and in vitro: ex vivo in culture medium less than 24 h after sampling and in vitro after demembranation and reactivation according to a standard procedure developed in our laboratory. Measuring the ATP-reactivated ciliary beat frequency allowed us to check the thermal parameters of the dynein ATPase and all the axonemal machinery. No significant difference in frequency was observed between nasal fossae cilia and tracheal cilia when comparing extreme temperatures in both experimental procedures.     

Sound production associated with feeding behaviour of the tsetse, Glossina M. morsitans

Summary Sounds produced during prefeeding, feeding and postfeeding behaviour of the tsetse, Glossina m. morsitans Westw. were investigated. Males and virgin very seldom sang before feeding but mated sang in more than 20% of the cases before taking a meal. Sound production during engorgement was negligible among all 3 groups. Postfeeding sounds were the most commonly produced, mated singing significantly more than virgin and both these groups more than . The mean duration of the postfeeding sounds did not differ between the sexes. Within each group, postfeeding sound production did not significantly change with age. There were, however, significant differences in the patterns of postfeeding sound production when were compared to over a period of 8 weeks.Oscillograms of these sounds indicated that the songs differed between the sexes and also varied from time to time. The sounds were composed of frequencies up to 50 kHz with the exception of the prefeeding sounds which did not contain any ultrasonic components. The most dominant frequency was centered between 1.5–2.5 kHz. Peaks were also observed between 0.5–0.8 kHz and around 5 kHz and 9 kHz. Prefeeding songs were of a weaker intensity than postfeeding songs.It is suggested that the sounds associated with feeding behaviour play a role in attracting hungry flies to suitable hosts and that, the low frequency components having higher intensities (30–40 dB) than the ultrasonic frequencies (10 dB) carry the most important part of the acoustic information.

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Résumé L'étude a porté sur les sons produits pendant les comportements préalimentaire, alimentaire et postalimentaire de la mouche Tsétsé, Glossina morsitans morsitans.Les mâles et les femelles vierges chantent très rarement avant l'alimentation, mais les femelles fécondées chantent dans plus de 20% des cas avant de prendre un repas. La production de sons pendant la prise de nourriture était négligeable pour les trois catégories. Les sons postalimentaires étaient plus fréquents, les femelles fécondées chantant plus que les femelles vierges et l'ensemble des femelles plus que les mâles. La durée des sons postalimentaires ne différait pas suivant les sexes. Dans chaque catégorie, les sons postalimentaires ne changaient pas significativement avec l'âge. Il y a eu, cependant, des différences significatives dans les caractéristiques de la production de son postalimentaire lorsque les mâles étaient comparés aux femelles pendant une période de 8 semaines.Les oscillogrammes de ces sons différaient suivant le sexe et variaient de temps en temps. Les sons comportaient des fréquences jusqu' à 50 kHz, à l'exception des sons préalimentaires des mâles qui ne contenaient pas d'ultrasons. Les fréquences les plus dominantes étaient concentrées entre 1,5–2,5 kHz. Des pics étaient observés entre 0,5–0,8 kHz et autour de 5 kHz et 9 kHz. Les sons préalimentaires étaient plus faibles que les sons postalimentaires. On en suggère que les sons associés au comportement alimentaire jouent un rôle en attirant les mouches affamées vers un hôte convenable et que la plus grande partie de l'information acoustique est portée par les composantes à basse fréquence qui ont une intensité plus élevée (30–40 dB) que les fréquences ultrasoniques (10 dB).

     

On the seasonal distribution of sunspot frequency

Abstract

Using the Zürich sunspot data, the seasonal distribution of all sunspot‐groups and of all new‐formed groups from 1938 to the last solar minimum in 1976 was investigated.

It is shown that there exist different distributions for the northern and southern solar hemisphere with maxima in the third and second quarter of the years, respectively, and seasonal differences in the north‐south asymmetry.

These results confirm the presumption of an influence of interstellar matter on solar activity.     

Preliminary investigation of the use of high frequency ultrasound imaging in the chick embryo

BACKGROUND: The purpose of this study was to investigate the feasibility of using high frequency ultrasound to study the chick embryo in a noninvasive and longitudinal fashion. METHODS: A total of 10 SPF White Leghorn chick embryos (GDs 11-17; Hamburger and Hamilton stage 37-43) were consecutively examined with a GE Logiq 400 ProSeries ultrasound unit using an 11-MHz small parts ultrasound probe. Access for ultrasound visualization of the embryos was accomplished by opening a 2-3-cm window either in the air cell over the blunt end of the egg or laterally over the embryo-dependent side of the egg. Warmed ultrasound coupling gel was used for imaging, and thermal regulation was maintained with infant heel warmers. The ultrasound images were recorded directly on digital video using a Sony TRV 900 DV camcorder. The images were directly converted to jpeg and mjeg2 files for further analysis. RESULTS: Effective visualization of each embryo was possible on each day of the study period. The embryos were best visualized through the opening made in the air cell at the blunt end of the egg. The extent of the anatomic survey of the chick embryo was dependent upon the position of the embryo in the egg relative to the opening in the air cell. Doppler color flow mapping studies were obtained of the embryonic and extraembryonic circulation. CONCLUSIONS: This preliminary investigation clearly shows the feasibility of high frequency ultrasound imaging to study chick embryo development in a longitudinal and noninvasive fashion. Further studies are presently ongoing regarding earlier embryo development, as well as to determine the stability and dynamics of the methodology.     

The effect of frequency and grounding on whole-body absorption of humans in E-polarized radiofrequency fields

The radiofrequency absorption rates of five male human volunteers have been measured from 3 to 41 MHz. The subjects were exposed at about 10 microW /cm2 inside a very large transverse electromagnetic (TEM) cell and never absorbed more than 1 W. Both the EKH and EHK orientations were employed under both free-space and grounded conditions. Absorption rates for the EKH orientation exceed those of the EHK orientation by 40% in free space, but only by 6% when grounded. The absorption rates for the grounded men vary with frequency, f, as f1.9 from 3 to 25 MHz and then level off at peak. The free-space absorption rates vary as f1.7 from 3 to 18 MHz and as f2.9 from 18 to 41 MHz. The average measured absorption rates at 10 MHz exceed the average of the standard model calculations by a factor of three (for free space) or four (grounded). The average man, when exposed grounded in an EKH orientation to the maximum permitted exposure levels under ANSI standard C95 .1-1982, will absorb 0.58 +/- 0.14 W/kg over most of the 3 to 41-MHz frequency range. This slightly exceeds the whole-body maximum of 0.40 W/kg underlying the standard.     

Numerical modeling and dosimetry of the 35 mm Petri dish under 46 GHz millimeter wave exposure

Experimental studies on effects of millimeter wave (MMW) exposure on cells cultured in Petri dishes have attracted interest in recent decades. To improve the quantification of the biological responses toward the MMW energy, an accurate and precise MMW dosimetry is to be provided. By using the finite difference time domain (FDTD) method, the numerical dosimetry is performed for a typical 35 mm Petri dish under 46 GHz continuous MMW exposure from an irradiator of a specified power pattern. With the aim of building a precise model, the meniscus at the interface between the culture solution and the Petri dish sidewall is taken into account, followed by the modeling of smooth edges of the Petri dish. The trilinear interpolation is introduced to assist the FDTD method to obtain a more precise dosimetric assessment. The specific absorption rate (SAR) distributions in the cornea cells covered by culture solution in the Petri dish are calculated and compared to display the effects of using Petri dish models of various precision and the trilinear interpolation on dosimetry results. In addition, the SAR distribution in the cells is analyzed to study its homogeneity. The results indicate that the precise Petri dish model and the application of the trilinear interpolation are helpful in improving the precision of numerical dosimetry. It is also revealed that the inhomogeneity of the SAR distribution is well beyond neglect, which deserves cautious consideration in experiments investigating MMW effects on cells in vitro.     

The influence of the frequency of periodic disturbances on the maintenance of phytoplankton diversity

The influence of periodic disturbances of various frequency on the maintenance of the phytoplankton diversity was studied by semicontinuous competition experiments. Disturbances consisted of dilution events, which meant both addition of fresh nutrients and elimination of organisms. The intervals between dilution events varied from 1 to 14 days. Diversity was found to increase with increasing intervals between disturbances. coexisting species belonged to different strategy types: (a) species with rapid growth under enriched conditions, (b) species with good competitive abilities under impoverished conditions, (c) species with the ability to build up storage pools of the limiting nutrient. An increase of the number of coexisting species over the number that would have coexisted in steady state was only found when the interval exceeded one generation time.     

Estimation of surface heat flux and temperature distributions in a multilayer tissue based on the hyperbolic model of heat conduction

In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown time-dependent surface heat flux in a skin tissue, which is stratified into epidermis, dermis, and subcutaneous layers, from the temperature measurements taken within the medium. Subsequently, the temperature distributions in the tissue can be calculated as well. The concept of finite heat propagation velocity is applied to the modeling of the bioheat transfer problem. The inverse solutions will be justified based on the numerical experiments in which two different heat flux distributions are to be determined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors on the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent surface heat flux can be obtained for the test cases considered in this study.     

A study of human myocardial tissue in Chagas' disease: distribution and frequency of inflammatory cell types

Although many reports have described the presence of inflammatory cells in chagasic lesions, the precise role(s) of these cells and whether their numbers in the lesions correlate with lesion severity are not known. In this work, we determined the numbers of mononuclear cells, neutrophils and eosinophils present in lesion sites of heart tissue sections from one acute and nine chronic chagasic patients. These numbers were independently recorded for five types of histologic patterns (HP) defined by the following characteristics: interstitial myocarditis with degeneration and necrosis of muscle fibers (HP I), interstitial myocarditis with preservation of muscle fibers (HP II), minimal or absent myocarditis with essentially preserved myocardium (HP III), interstitial fibrosis (HP IV), and myocytolysis (HP V). The largest numbers of inflammatory cells were found in HP I where substantial numbers of eosinophils were found. Eosinophils were frequently seen in areas showing HP I in the tissue sections from the patients with the most severe myocarditis (in terms of the high frequency of necrotic areas in HP I). Eosinophils were also seen in areas of HP III, i.e. in relatively preserved areas of tissue sections from patients displaying the most severe myocarditis, although in lesser numbers than found in HP I. The smallest numbers of inflammatory cells were seen in HP III, where the myocardium was essentially intact. Although significant numbers of inflammatory cells were seen in HP II and IV, eosinophils were either present in small numbers or absent, and there was no obvious correlation between the content of any of the monitored cell types and the overall intensity of myocarditis. The presence of relatively large proportions of eosinophils in tissue areas with HP I type of lesions would appear to implicate these cells in the production of chagasic heart lesions.     

Effect of tissue and atmosphere's parameters on human eye temperature distribution

A three dimensional finite element method analysis was employed to investigate the effect of tissue and atmosphere parameters namely, ambient temperature, ambient convection coefficient, local blood temperature, and blood convection coefficient upon temperature distribution of human eyes. As a matter of simplification, only eye ball and skull bone are considered as the system of eye modeling. Decreasing the local blood temperature and keeping it cool is one of the most important ways to control bleeding during surgeries. By lower temperature of body organs such as the eye, the need for oxygenated blood is reduced, allowing for an extension in time for surgery. With this in mind, this study is done to see which one of parameters, such as ambient temperature, ambient convection coefficient, local blood temperature, and blood convection coefficient, has an effective role in decreasing the temperature of the eye. To this end, 3 different paths were employed to find out about the temperature distribution through the eye. The analysis of the three paths demonstrates the interaction of ambient and blood temperature in modeling temperature changes in specific locations of the eye. These data will be important in applications such as eye surgery, relaxation, and sleep therapy.     

The effect of trauma on dream content--A field study of Palestinian children.

In the present study, we compared the frequency and intensity of threatening events in the dreams of traumatized and nontraumatized Palestinian children. The aim of the study was to test some of the predictions and hypotheses derived from the Threat Simulation Theory proposing an evolutionary function for dreaming. Most, but not all, of our hypotheses were supported by the findings. We discuss the results in the light of the Threat Simulation Theory, and we also consider whether alternative theories of dream function are able to account for them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

应用反频次比较法研究浙江双栉蝠蛾幼虫空间分布格局

本文应用反频次比较法在福建邵武市11块毛竹Phyllostachys heterocycla cv. pubescens林样地上调查浙江双栉蝠蛾Bipectilus zhejiangensis幼虫的空间分布格局及该虫的发生与生态环境的关系。调查结果表明： 以每株毛竹笋为单位, 通过正频次比较法分析, 浙江双栉蝠蛾幼虫在总计抽样的550株竹笋上的分布符合负二项分布。以样地为单位, 经过反频次比较法分析11块样地上浙江双栉蝠蛾的分布类型, 结果为： 样地1, 2, 4, 5和8属于奈曼分布, 样地7, 9, 10和11属于负二项分布, 样地3和6属于奈曼分布或负二项分布。判别分析法判别函数能够100%正确分组, 依据F值大小, 6个环境指标的重要性从大到小依次为： 土壤有机质（X₅）、 林地卫生（X₆）、 坡位（X₃）、 坡向（X₄）、 竹林结构（X₂）、 立竹度（X₁）。由此得出： 无论是以每株毛竹笋为单位, 还是以每个样地为研究对象或单位, 都表明浙江双栉蝠蛾幼虫在空间分布上属于非均匀的聚集型分布。土壤腐殖质厚、 林地卫生差可使双栉蝠蛾幼虫密度增大, 立竹度、 竹林结构、 坡位和坡向单个指标对浙江双栉蝠蛾幼虫密度的影响不明显, 但综合作用明显; 反频次比较法比聚集度指标评价更为详细科学。     

The effect of vibration frequency and amplitude on biofouling deterrence

The use of vibration is proposed as a means of controlling the settlement of marine fouling organisms. In this study, panels with embedded lead zirconate titanate, known as PZT, were placed in the field over 3?months. The panels were vibrated at different velocity levels at frequencies between 70 and 445?Hz. It was found that barnacles (Amphibalanus variegatus Darwin and Elminius sp.) were the only fouling organisms affected by the applied vibration, and these organisms settled in significantly lower numbers when the plates were excited at specific frequencies and amplitudes. Panels vibrating at relatively higher frequencies, greater than 260?Hz, exhibited reduced barnacle settlement, whilst lower frequencies in the 70–100?Hz range had little or no effect. The settlement of other fouling organisms such as tubeworms, bryozoans, ascidians and algae did not appear to be affected by the applied excitation. The experimental results showed that increasing the velocity amplitude of vibration was a contributing factor in inhibiting barnacle settlement.