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A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological Particles with an Acoustic Microdevice

A major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. ...

Lawrence Livermore National Laboratory

The present study investigates patient perceptions of the quality of discharge instruction by assessing inpatients' ratings of care and service in the United States over the past 5 years (1997-2001) (n = 4,901,178). As expected, patients' ratings of "instructions given about how to care for yourself at home" showed a strong, consistent positive relationship with overall patient satisfaction from 1997 through 2001. Nevertheless, patient satisfaction with discharge instructions decreased significantly each year (p < 0.001). Patients gave lower ratings to the quality of discharge instruction than to the overall quality of their hospital stay which indicates a failure to match the quality delivered among other services within the hospital. Patient assessments of discharge instruction quality varied systematically among conditions. Patients with musculoskeletal diseases and disorders (MDC-8) rated discharge instruction considerably lower than all other patient groups. Patients' age, sex, self-described health status and length of stay did not predict patients' evaluations of discharge instructions. U.S. hospitals may not be meeting existing AMA and JCAHO standards for patient education and discharge.

Patient perceptions of quality in discharge instruction.

Photocatalytic lithography couples light with photoreactive coated mask materials to pattern surface chemistry. We excite porphyrins to create radical species that photocatalytically oxidize, and thereby pattern, chemistries in the local vicinity. The technique advantageously is suited for use with a wide variety of substrates. It is fast and robust, and the wavelength of light does not limit the resolution of patterned features. We have patterned proteins and cells to demonstrate the utility of photocatalytic lithography in life science applications.

Porphyrin-based photocatalytic lithography.

Care in the right place.

Conventional radiotherapy or hypofractionation? A study of molecular changes resulting from different radiation fractionation schemes.

The activity of certain kinases can promote cell survival after DNA damage, but the role of phosphatases in determining cell fate, although documented, is much less well defined. We sought to define a role for phosphatases in radiation survival and identify potential targets for intervention. By using naturally occurring inhibitors and siRNA we have assessed inhibition of four serine/threonine phosphatases PP1, PP2A, PHLPP and PHLPPL in a panel of tumor cell lines with H-, K- or N-ras mutations or with EGFR activation for effects on tumor cell radiosensitivity. Calyculin A, which inhibits both PP1 and PP2A reduced radiation survival in SQ20B cells (overexpressing EGFR). Okadaic acid, which preferentially inhibits PP2A showed less effect in SQ20B cells suggesting a greater involvement of PP1 in modulating radiosensitivity of these cells. T24 cells (H-Ras mutant) appeared equally sensitive to both inhibitors. The suggestion from inhibitors that PP1 might be important in radiosensitivity was supported by the greater sensitization obtained after knocking down expression of the catalytic sub-unit of PP1 over that seen after PP2A knockdown. Knocking down the PP2C like phosphatase PHLPPL also increased radiosensitivity in all cell lines tested where a second isoform PHLPP had little effect. These data suggest that targeted inhibition of phosphatase activity may be an alternative to kinase inhibition to enhance radiosensitivity in tumors.

Phosphatase inhibition and cell survival after DNA damage induced by radiation.

This review will examine the role of phosphatases in cancer cell signalling and also outline emerging findings regarding the influence of phosphatases on tumor cell survival after ionising radiation.

Cell signalling and radiation survival: the impact of protein phosphatases.

Diagnosis and treatment of human diseases frequently requires isolation and detection of certain cell types from a complex mixture. Compared with traditional separation and detection techniques, microfluidic approaches promise to yield easy-to-use diagnostic instruments tolerant of a wide range of operating environments and capable of accomplishing automated analyses. These approaches will enable diagnostic advances to be disseminated from sophisticated clinical laboratories to the point-of-care. Applications will include the separation and differential analysis of blood cell subpopulations for host-based detection of blood cell changes caused by disease, infection, or exposure to toxins, and the separation and analysis of surface-sensitized, custom dielectric beads for chemical, biological, and biomolecular targets. Here we report a new particle separation and analysis microsystem that uses dielectrophoretic field-flow fractionation (DEP-FFF). The system consists of a microfluidic chip with integrated sample injector, a DEP-FFF separator, and an AC impedance sensor. We show the design of a miniaturized impedance sensor integrated circuit (IC) with improved sensitivity, a new packaging approach for micro-flumes that features a slide-together compression package and novel microfluidic interconnects, and the design, control, integration and packaging of a fieldable prototype. Illustrative applications will be shown, including the separation of different sized beads and different cell types, blood cell differential analysis, and impedance sensing results for beads, spores and cells.

DIELECTROPHORESIS-BASED MICROFLUIDIC SEPARATION AND DETECTION SYSTEMS.

Community differentiation is a fundamental topic of the social sciences, and its prehistoric origins in Europe are typically assumed to lie among the complex, densely populated societies that developed millennia after their Neolithic predecessors. Here we present the earliest, statistically significant evidence for such differentiation among the first farmers of Neolithic Europe. By using strontium isotopic data from more than 300 early Neolithic human skeletons, we find significantly less variance in geographic signatures among males than we find among females, and less variance among burials with ground stone adzes than burials without such adzes. From this, in context with other available evidence, we infer differential land use in early Neolithic central Europe within a patrilocal kinship system.

Julie Hamilton

Materials Engineering Division

Lawrence Livermore National Laboratory

A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological Particles with an Acoustic Microdevice

Julie Hamilton

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Materials Engineering Division

Lawrence Livermore National Laboratory

A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological Particles with an Acoustic Microdevice

Materials Engineering Division