芫花花蕾中的两个新二萜

瑞香烷型二萜类化合物具有良好的抗肿瘤生理活性.为了进一步研究该类抗肿瘤活性成分,对富含瑞香烷型二萜的芫花花蕾进行化学成分研究,从中分离得到一个巴豆烷型二萜1和两个瑞香烷型二萜原酸酯2和3.应用多种波谱学方法（1H NMR,13C NMR,HSQC,HMBC,NOESY,ESI-MS,HR-ESI-MS等）,确定了3个化...     

Lab-on-a-chip devices for global health: past studies and future opportunities

A rapidly emerging field in lab-on-a-chip (LOC) research is the development of devices to improve the health of people in developing countries. In this review, we identify diseases that are most in need of new health technologies, discuss special design criteria for LOC devices to be deployed in a variety of resource-poor settings, and review past research into LOC devices for global health. We focus mainly on diagnostics, the nearest-term application in this field.     

Measurement of the eta-meson mass using psi(2S) --> etaJ/psi

We measure the mass of the eta meson using psi(2S) --> etaJ/psi events acquired with the CLEO-c detector operating at the CESR e(+)e(-) collider. Using the four decay modes eta --> gamma gamma, 3pi(0), pi(+)pi(-)pi(0), and pi(+)pi(-)gamma, we find M(eta) = 547.785 +/- 0.017 +/- 0.057 MeV, in which the first uncertainty is statistical and the second systematic. This result has an uncertainty comparable to the two most precise previous measurements and is consistent with that of NA48, but is inconsistent at the level of 6.5 sigma with the much smaller mass obtained by GEM.     

Overall dynamic constitutive relations of layered elastic composites

A method for the homogenization of a layered elastic composite is presented. It allows direct, consistent, and accurate evaluation of the averaged overall frequency-dependent dynamic material constitutive relations without the need for a point-wise solution of the field equations. When the spatial variation of the field variables is restricted by Bloch-form (Floquet-form) periodicity, then these relations together with the overall conservation and kinematical equations accurately yield the displacement or stress mode-shapes and, necessarily, the dispersion relations. The method can also give the point-wise solution of the elastodynamic field equations (to any desired degree of accuracy), which, however, is not required for the calculation of the average overall properties. The resulting overall dynamic constitutive relations are general and need not be restricted by the Bloch-form periodicity.The formulation is based on micromechanical modeling of a representative unit cell of the composite. For waves in periodic layered composites, the overall effective mass-density and compliance (stiffness) are always real-valued whether or not the corresponding unit cell (representative volume element used as a unit cell) is geometrically and/or materially symmetric. The average strain and linear momentum are coupled and the coupling constitutive parameters are always each others' complex conjugates. We separate the overall constitutive relations, which depend only on the composition and structure of the unit cell, from the overall field equations which hold for any elastic composite; i.e., we use only the local field equations and material properties to deduce the overall constitutive relations. Finally, we present solved numerical examples to further clarify the structure of the averaged constitutive relations and to bring out the correspondence of the current method with recently published results.     

Commercialization of microfluidic point-of-care diagnostic devices

A large part of the excitement behind microfluidics is in its potential for producing practical devices, but surprisingly few lab-on-a-chip based technologies have been successfully introduced into the market. Here, we review current work in commercializing microfluidic technologies, with a focus on point-of-care diagnostics applications. We will also identify challenges to commercialization, including lessons drawn from our experience in Claros Diagnostics. Moving forward, we discuss the need to strike a balance between achieving real-world impact with integrated devices versus design of novel single microfluidic components.     

Spatial and seasonal behaviour of organotin compounds in protected subtropical estuarine ecosystems in Okinawa,Japan

The spatial and temporal behaviours of the organotin compounds (OTCs) (butyl- and phenyltin) were investigated in the Manko and Okukubi protected estuarine ecosystems on Okinawa Island, Japan from February to October 2006. Butyltin compounds (BTCs) were frequently detected in all seasons, while phenyltin (PhTs) were found in winter and early spring. In Manko estuary, the total mean concentrations of BTCs and PhTs were 22.78?±?30.85, (mean?±?SD, n?=?53) and 0.08?±?0.27?ng(Sn)?L^?1, respectively. In Okukubi estuary, BTCs and PhTs were 12.58?±?23.96 and 0.47?±?1.67 (n?=?55) ng(Sn)?L^?1, respectively. The Manko sediments can be classified as lightly contaminated, while the Okukubi sediments were uncontaminated with tributyltin (TBT). The mean levels of TBT shown in Manko estuary exceeded the threshold level and represent an ecotoxicological risk to sensitive aquatic life. Generally, the present study reports the occurrence and continuous input of OTCs in the protected estuaries, even 16 years after legal restriction of TBT usage in coastal waters was implemented by the Japanese Environmental Authorities.     

Miniaturized capillary isoelectric focusing in plastic microfluidic devices

We report the demonstration of miniaturized capillary isoelectric focusing (CIEF) in plastic microfluidic devices. Conventional CIEF technique was adapted to the microfluidic devices to separate proteins and to detect protein-protein interactions. Both acidic and basic proteins with isoelectric points (pI) ranging from 5.4 to 11.0 were rapidly focused, mobilized, and detected in a 1.2 cm long channel (50 microm deep x 120 microm wide) with a total analysis time of 150 s. In a device with a focusing distance of 4.7 cm, the separation efficiency for a basic protein, lysozyme, was achieved as high as 1.5 x 10(5) plates, corresponding to 3.2 million plates per meter. We also experimentally confirmed that IEF resolution is essentially independent of focusing length when the applied voltage is kept the same and within a range that it does not cause Joule heating. Further, we demonstrated the use of miniaturized CIEF to study the interactions between two pairs of proteins, immunoglobulin G (IgG) with protein G and anti-six histidine (anti-6xHis) with 6xHis-tagged green fluorescent protein (GFP). Using this approach, protein-protein interactions can be detected for as little as 50 fmol of protein. We believe miniaturized CIEF is useful for studying protein-protein interactions when there is a difference in pI between a protein-protein complex and its constitutent proteins.