Coherent Transport Through a Quadruple Point in a Few Electron Triple Dot

A few electron double electrostatic lateral quantum dot can be transformed into a few electron triple quantum dot by applying a different combination of gate voltages. Quadruple points have been achieved at which all three dots are simultaneously on resonance. At these special points in the stability diagram four occupation configurations are possible. Both charge detection and transport experiments have been performed on this device. In this short paper we present data and confirm that transport is coherent by observing a Pi phase shift in magneto-conductance oscillations as one passes through the quadruple point.Comment: To be published in ICPS Conf. Proceedings 200

A Tuneable Few Electron Triple Quantum Dot

In this paper we report on a tuneable few electron lateral triple quantum dot design. The quantum dot potentials are arranged in series. The device is aimed at studies of triple quantum dot properties where knowing the exact number of electrons is important as well as quantum information applications involving electron spin qubits. We demonstrate tuning strategies for achieving required resonant conditions such as quadruple points where all three quantum dots are on resonance. We find that in such a device resonant conditions at specific configurations are accompanied by novel charge transfer behaviour.Comment: 11 pages, 4 figure

Conditional preparation of states containing a definite number of photons

A technique for conditionally creating single- or multimode photon-number states is analyzed using Bayesian theory. We consider the heralded N-photon states created from the photons produced by an unseeded optical parametric amplifier when the heralding detector is the time-multiplexed photon-number-resolving detector recently demonstrated by Fitch, et al. [Phys. Rev. A 68, 043814 (2003).] and simultaneously by Achilles, et al. [Opt. Lett. 28, 2387 (2003).]. We find that even with significant loss in the heralding detector, fields with sub-Poissonian photon-number distributions can be created. We also show that heralded multimode fields created using this technique are more robust against detector loss than are single-mode fields.Comment: 6 pages, 6 figures, reference added, typos corrected, content update

Relationship between the molecular composition, visible light absorption, and health-related properties of smoldering woodsmoke aerosols

Organic aerosols generated from the smoldering combustion of wood critically impact air quality and health for billions of people worldwide; yet, the links between the chemical components and the optical or biological effects of woodsmoke aerosol (WSA) are still poorly understood. In this work, an untargeted analysis of the molecular composition of smoldering WSA, generated in a controlled environment from nine types of heartwood fuels (African mahogany, birch, cherry, maple, pine, poplar, red oak, redwood, and walnut), identified several hundred compounds using gas chromatography mass spectrometry (GCMS) and nano-electrospray high-resolution mass spectrometry (HRMS) with tandem multistage mass spectrometry (MSn). The effects of WSA on cell toxicity as well as gene expression dependent on the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER) were characterized with cellular assays, and the visible mass absorption coefficients (MACvis) of WSA were measured with ultraviolet-visible spectroscopy. The WSAs studied in this work have significant levels of biological and toxicological activity, with exposure levels in both an outdoor and indoor environment similar to or greater than those of other toxicants. A correlation between the HRMS molecular composition and aerosol properties found that phenolic compounds from the oxidative decomposition of lignin are the main drivers of aerosol effects, while the cellulose decomposition products play a secondary role; e.g., levoglucosan is anticorrelated with multiple effects. Polycyclic aromatic hydrocarbons (PAHs) are not expected to form at the combustion temperature in this work, nor were they observed above the detection limit; thus, biological and optical properties of the smoldering WSA are not attributed to PAHs. Syringyl compounds tend to correlate with cell toxicity, while the more conjugated molecules (including several compounds assigned to dimers) have higher AhR activity and MACvis. The negative correlation between cell toxicity and AhR activity suggests that the toxicity of smoldering WSA to cells is not mediated by the AhR. Both mass-normalized biological outcomes have a statistically significant dependence on the degree of combustion of the wood. In addition, our observations support the fact that the visible light absorption of WSA is at least partially due to charge transfer effects in aerosols, as previously suggested. Finally, MACvis has no correlation with toxicity or receptor signaling, suggesting that key chromophores in this work are not biologically active on the endpoints tested

Femtosecond laser machining of multi-depth microchannel networks onto silicon

Direct writing of multi-depth microchannel branching networks into a silicon wafer with femtosecond pulses at 200 kHz is reported. The silicon wafer with the microchannels is used as the mold for rapid prototyping of microchannels on polydimethylsiloxane. The branching network is designed to serve as a gas exchanger for use in artificial lungs and bifurcates according to Murray's law. In the development of such micro-fluidic structures, processing speed, machining range with quality surface, and precision are significant considerations. The scan speed is found to be a key parameter to reduce the processing time, to expand the machining range, and to improve the surface quality. By fabricating a multi-depth branching network as an example, the utilization of femtosecond pulses in the development of microfluidic devices is demonstrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90801/1/0960-1317_21_4_045027.pd

Different response to epidermal growth factor of hepatocytes in cultures isolated from male or female rat liver. Inhibitor effect of estrogen on binding and mitogenic effect of epidermal growth factor

Deoxyribonucleic acid (DNA) synthesis in hepatocytes isolated from the livers of male and female rats has been compared in monolayer culture. Plating efficiency, DNA and protein content, viability, and morphologic appearance were the same in cultures prepared with hepatocytes isolated from male or female rats. Epidermal growth factor (EGF)-induced DNA synthesis was significantly higher in hepatocytes from male rats than in hepatocytes from female rats. This was the case whether hepatocytes were isolated from normal or partially hepatectomized male or female rats. Hepatocytes isolated from regenerating liver synthesize more DNA than those isolated from normal liver in response to EGF. This increased response to EGF in hepatocytes derived from regenerating liver was relatively the same for male- and female-derived hepatocytes, but the magnitude of the response was considerably higher in male-derived hepatocytes. In contrast, in vivo DNA synthesis in the liver remnant after partial hepatectomy was similar in male and female rats if measured 24 h after the operation. A comparison of EGF binding to male- and female-derived hepatocytes maintained in primary culture indicated a lower number of high-affinity receptors for EGF in the female hepatocytes. The addition of estrogen to primary cultures of hepatocytes isolated from male rats inhibited EGF binding as well as EGF-induced DNA synthesis. Our studies show significant differences in DNA synthesis in response to EGF when male and female hepatocytes are compared in primary culture. The regenerative response after partial hepatectomy, on the other hand, was the same in male and female rats. Thus, our studies indicate that the sex of the donor rat is important when hepatocytes in culture are used for a variety of studies, such as hepatocyte metabolism, induction and control of DNA synthesis, and hepatocarcinogenesis. In addition, our results indicate that caution is advised when inferences are made from in vitro findings for in vivo conditions. © 1987

The likely implications of the 1997 Coroners Ordinance on the autopsy service of a teaching hospital

The new Hong Kong Coroners Ordinance was published in April 1997. It introduced an expanded set of guidelines for reporting deaths to the coroner as well as the threat of criminal proceedings for non-compliance. The Ordinance is due to be implemented in early 1998. The aim of this study is to determine the likely effect of the new law on the relative proportion of coroner's and hospital (consent) autopsies. A total of 352 consecutive autopsy cases were reviewed; 170 (48.3%) were referred for coroner's autopsies and 182 (51.7%) for hospital autopsies. But applying the criteria of the current ordinance, there should have been 213 (60.5%) coroner's cases and 139 (39.5%) hospital autopsiesԸ?that is, 43 hospital autopsies should have been coroner's autopsies. Under the new Coroners Ordinance, there would be 300 (85.2%) coroner's autopsies and only 52 (14.8%) hospital autopsies. The new Coroners Ordinance is likely to result in a greater number of requests for coroner's autopsies with a corresponding decline in hospital autopsiesԸ?in our case, a shift from 48.3% of all autopsies performed to 85.2%! This increase would be due largely to the requirement for reporting stillbirths but would also be due to increased reporting for fear of Ը?criminal proceedings' for non-compliance. An absolute increase in the number of autopsies is also anticipated, although the magnitude cannot as yet be predicted.published_or_final_versio

“Breaking the rules”: A reflective processual analysis of multidisciplinary academic collaboration.

Three academics from different fields collaborated on a study in which we reflected on our group involvement. Although we originally worked together to provide our different perspectives on how to use debates in online courses, we found that our multidisciplinary collaboration evolved into self-study as we each wrote narratives about our own participation which we then discussed and interpreted from our unique perspectives. Despite the fact that our members consisted of someone from nursing, someone from business, and someone in psychology, we all agreed that we engaged in a successful collaboration, as assessed by our desire to work together again and by the joint publication of an article. This paper presents our individual and collective interpretations of our attempts to understand why we were successful in this project, even though we did not follow most of the principles of multidisciplinary collaboration, nor of the usual conventions of our respective disciplines