Nanocrystalline diamond microelectrode arrays fabricated on sapphire technology for high-time resolution of quantal catecholamine secretion from chromaffin cells

The quantal release of oxidizable molecules can be successfully monitored by means of polarized carbon fiber microelectrodes (CFEs) positioned in close proximity to the cell membrane. To partially overcome certain CFE limitations, mainly related to their low spatial resolution and lack of optical transparency, we developed a planar boron-doped nanocrystalline diamond (NCD) prototype, grown on a transparent sapphire wafer. Responsiveness to applied catecholamines as well as the electrochemical and optical properties of the NCD-based device were first characterized by cyclic voltammetry and optical transmittance measurements. By stimulating chromaffin cells positioned on the device with external KCl, well-resolved quantal exocytotic events could be detected either from one NCD microelectrode, or simultaneously from an array of four microelectrodes, indicating that the chip is able to monitor secretory events (amperometric spikes) from a number of isolated chromaffin cells. Spikes detected by the planar NCD device had comparable amplitudes, kinetics and vesicle diameter distributions as those measured by conventional CFEs from the same chromaffin cell.

SNF5, a core component of the SWI/SNF complex, is necessary for p53 expression and cell survival, in part through eIF4E

SNF5, a core component of the SWI/SNF chromatin remodeling complex, is expressed as two isoforms, SNF5a and SNF5b. SNF5 is a tumor suppressor as mutation of SNF5 leads to tumor formation and cooperates with p53 deficiency to enhance cancer susceptibility. Interestingly, lack of SNF5 inhibits cell survival and embryonic development potentially via abnormal activation of p53. To further examine this, we generated cell lines in that SNF5a, SNF5b, or both can be inducibly knocked down. We found that SNF5 knockdown leads to cell cycle arrest in G1, and SNF5a and SNF5b are functionally redundant. We also showed that SNF5 knockdown impairs p53-dependent transcription of p21 and MDM2. However, contrary to earlier reports that p53 is activated by SNF5 knockout in murine cells, SNF5 knockdown leads to decreased, but not increased, expression of both basal and stress-induced p53 in multiple human cell lines. In addition, we showed that SNF5 knockdown induces AMPK activation and inhibits eIF4E expression. Finally, we demonstrated that SNF5 knockdown inhibits p53 translation via eIF4E and replacement of eIF4E in SNF5-knockdown cells restores p53 expression and cell survival. Together, our results suggest that the p53 pathway is regulated by, and mediates the activity of, SNF5 in tumor suppression and pro-survival.

Building Caries Risk Assessment Models for Children

Despite the well-recognized importance of caries risk assessment, practical models remain to be established. This study was designed to develop biopsychosocial models for caries risk assessment in various settings. With a questionnaire, an oral examination, and biological (salivary, microbiological, and plaque pH) tests, a prospective study was conducted among 1782 children aged 3-6 years, with 1576 (88.4%) participants followed in 12 months. Multiple risk factors, indicators, and protective factors were identified. Various risk assessment models were constructed by the random selection of 50% of the cases and further validated in the remaining cases. For the prediction of a “one-year caries increment”, screening models without biological tests achieved a sensitivity/specificity of 82%/73%; with biological tests, full-blown models achieved the sensitivity/specificity of 90%/90%. For identification of a quarter of the children with high caries burden (baseline dmft > 2), a community-screening model requiring only a questionnaire reached a sensitivity/specificity of 82%/81%. These models are promising tools for cost-effective caries control and evidence-based treatment planning. Abbreviations: decayed, missing, filled teeth in primary dentition (dmft); receiver operation characteristics (ROC); relative risk (RR); confidence interval (CI); National Institutes of Health (NIH); World Health Organization (WHO); US Department of Health and Human Services (US/DHHS); American Academy of Pediatric Dentistry (AAPD).

Measurements of h(c)(1P(1)) in psi' decays

We present measurements of the charmonium state h(c)(1P(1)) made with 106x10(6) psi' events collected by BESIII at BEPCII. Clear signals are observed for psi'-->pi0 h(c) with and without the subsequent radiative decay h(c)-->gamma eta(c). First measurements of the absolute branching ratios B(psi'-->pi0 h(c)) = (8.4+/-1.3+/-1.0) x 10(-4) and B(h(c)-->gamma eta(c)) = (54.3+/-6.7+/-5.2)% are presented. A statistics-limited determination of the previously unmeasured h(c) width leads to an upper limit Gamma(h(c))<1.44 MeV (90% confidence). Measurements of M(h(c)) = 3525.40+/-0.13+/-0.18 MeV/c2 and B(psi'-->pi0 h(c)) x B(h(c)-->gamma eta(c)) = (4.58+/-0.40+/-0.50) x 10(-4) are consistent with previous results.

Main features of the tomographic reconstruction algorithm OPED

This paper discusses the advantages of both geometry of data required for the reconstruction algorithm, orthogonal polynomial expansion on disc (OPED), and polynomial structure of this algorithm. We show that this type of geometry is a result of special parameterisation used within the OPED formalism. The practicability of the OPED data geometry is discussed and it is shown that the data of such geometry can be acquired directly. A method of reducing typical artefacts by using the polynomial structure of the algorithm is summarised as well.

Role of CK1 in GSK3beta-mediated phosphorylation and degradation of snail

The epithelial to mesenchymal transition (EMT) that occurs during embryonic development has begun to attract attention as a potential mechanism for tumor cell metastasis. Snail is a well-known Zn-finger transcription factor that promotes EMT by repressing E-cadherin expression. It is known that Snail is phosphorylated by GSK3beta and degraded by beta-TrCP-mediated ubiquitination. Here we described another protein kinase, CK1, whose phosphorylation of Snail is required for the subsequent GSK3beta phosphorylation. Specific inhibition or depletion of CK1varepsilon inhibits the phosphorylation and degradation of Snail and promotes cell migration, suggesting a central role of CK1varepsilon in the EMT process. Furthermore, our study uncovered distinct roles and steps of Snail phosphorylation by CK1varepsilon and GSK3beta. Taken together, we identified CK1varepsilon as a new component of the Snail-mediated EMT process, providing insight into the mechanism of human cancer metastasis.

An interval-parameter stochastic robust optimization model for supporting municipal solid waste management under uncertainty

A stochastic robust interval linear programming model (IPRO) was developed for supporting municipal solid waste management under uncertainty. The model improves upon the existing stochastic robust optimization (SRO) and interval linear programming (ILP) methods by allowing evaluations of trade-offs among expected costs, cost variability, and risk of violating relax constraints simultaneously, as well as reflections of complex uncertainties through both interval and stochastic theories. A long-term waste management problem was used to demonstrate the applicability of IPRO model. The results indicated that IPRO normally led to interval solutions, where waste-management alternatives could be generated by adjusting the decision-variable values within their intervals. The model could also help waste managers to identify desired policies that under various environmental, economic, system-feasibility and system-reliability constraints.

Sensitivity calibration procedures in optical-CT scanning of BANG 3 polymer gel dosimeters

The dose response of the BANG 3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4 x 4 cm2 photon fields or 6 x 6 cm2 electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6 x 6 cm2, 12 and 16 MeV electron fields. The dose response of the BANG3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752 +/- 3%, 0.0756 +/- 3%, 0.0767 +/- 3%, and 0.0759 +/- 3% cm(-1) Gy(-1)) and the PDD matching methods (0.0768 +/- 3% and 0.0761 +/- 3% cm(-1) Gy(-1)) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6 x 6 cm2 electron field. Three-dimensional dose distributions from the gel measurement and the Eclipse planning system (Varian Corporation, Palo Alto, CA) were compared and evaluated using 3% dose difference and 2 mm distance-to-agreement criteria.

Transcription activity is required for p53-dependent tumor suppression

As a transcription factor, the critical tumor suppressor, p53, directly regulates the transcription of hundreds of genes, leading to cell-cycle arrest, apoptosis, cellular senescence and differentiation. Although it has been assumed that p53 transcription activity is critical for tumor suppression, this assumption has been increasingly contested by recent findings of transcription-independent roles of p53 in apoptosis as well as findings that none of the mutant mice lacking important p53 transcription targets are cancer prone. On the basis of previous findings that p53 transcription activity is abolished in p53(QS) (Leu25Trp26 to Gln25Ser26) knock-in mouse cells after DNA damage, to determine the importance of transcription activity of p53 in tumor suppression, we generated knock-in mice that can conditionally express p53(QS) protein in a Cre-dependent manner. By breeding the knock-in mice with Lck-Cre transgenic mice that specifically express Cre in thymocytes, we show that p53-dependent suppression of thymic lymphomas is abolished in thymocytes expressing high levels of p53(QS) protein. In addition, p53(QS) protein is accumulated in some of the thymic tumors. Therefore, p53 transcription activity induced by DNA damage is required for tumor suppression. Together with the findings that the disruption of various p53-dependent functions individually fails to promote cancer, our findings indicate that various transcription-dependent functions of p53 must collaborate to efficiently suppress tumorigenesis.

A laser-Compton scattering prototype experiment at 100 MeV linac of Shanghai Institute of Applied Physics

As a prototype of the Shanghai Laser Electron Gamma Source in the Shanghai Synchrotron Radiation Facility, an x-ray source based on laser-Compton scattering (LCS) has been installed at the terminal of the 100 MeV linac of the Shanghai Institute of Applied Physics. LCS x-rays are generated by interactions between Q-switched Nd:yttrium aluminum garnet laser pulses [with wavelength of 1064 nm and pulse width of 21 ns (full width at half maximum)] and electron bunches [with energy of 108 MeV and pulse width of 0.95 ns (rms)] at an angle of 42 degrees between laser and electron beam. In order to measure the energy spectrum of LCS x-rays, a Si(Li) detector along the electron beam line axis is positioned at 9.8 m away from a LCS chamber. After background subtraction, the LCS x-ray spectrum with the peak energy of 29.1+/-4.4|(stat)+/-2.1|(syst) keV and the peak width (rms) of 7.8+/-2.8|(stat)+/-0.4|(syst) keV is observed. Normally the 100 MeV linac operates with the electron macropulse charge of 1.0 nC/pulse, and the electron and laser collision repetition rate of 20 Hz. Therefore, the total LCS x-ray flux of (5.2+/-2.0) x 10(2) Hz can be achieved.