Coherent Control and Spectroscopy of a Semiconductor Quantum Dot Wigner Molecule.

Semiconductor quantum dots containing more than one electron have found wide application in qubits, where they enable readout and enhance polarizability. However, coherent control in such dots has typically been restricted to only the lowest two levels, and such control in the strongly interacting regime has not been realized. Here we report quantum control of eight different transitions in a silicon-based quantum dot. We use qubit readout to perform spectroscopy, revealing a dense set of energy levels with characteristic spacing far smaller than the single-particle energy. By comparing with full configuration interaction calculations, we argue that the dense set of levels arises from Wigner-molecule physics.

Communication: Nonadditive dielectric susceptibility spectra of associating liquids.

Highly unusual linear-response spectra involving contributions from hydrogen-bonded supramolecular processes and from structural relaxations are found in 4-methyl-3-heptanol mixed with 2-ethyl-1-hexylbromide. Although the mean time scales of the underlying relaxations are separated by more than 3 decades, the overall spectra cannot be decomposed into a sum of these processes. This finding challenges the ubiquitous practice of disentangling susceptibility spectra of Debye liquids by adding suitable subspectra. The spectral shape of the studied viscous mixtures is excellently described using the Williams ansatz, here a necessary approach and not as previously considered merely an alternative to additive analyses.

Characterization of a gate-defined double quantum dot in a Si/SiGe nanomembrane.

We report the fabrication and characterization of a gate-defined double quantum dot formed in a Si/SiGe nanomembrane. In the past, all gate-defined quantum dots in Si/SiGe heterostructures were formed on top of strain-graded virtual substrates. The strain grading process necessarily introduces misfit dislocations into a heterostructure, and these defects introduce lateral strain inhomogeneities, mosaic tilt, and threading dislocations. The use of a SiGe nanomembrane as the virtual substrate enables the strain relaxation to be entirely elastic, eliminating the need for misfit dislocations. However, in this approach the formation of the heterostructure is more complicated, involving two separate epitaxial growth procedures separated by a wet-transfer process that results in a buried non-epitaxial interface 625 nm from the quantum dot. We demonstrate that in spite of this buried interface in close proximity to the device, a double quantum dot can be formed that is controllable enough to enable tuning of the inter-dot tunnel coupling, the identification of spin states, and the measurement of a singlet-to-triplet transition as a function of an applied magnetic field.

Progress in reducing the pale, soft and exudative (PSE) problem in pork and poultry meat.

Research in the area of the pale, soft and exudative (PSE) pork and poultry meat is reviewed in this article with an emphasis on genetic, biochemical and metabolic factors contributing to the problem. Over the past five decades, there has been much more work in the pork meat area where a few genetic markers have been identified, and are currently used to remove susceptible animals from the herd. Some of the markers are linked to aberrant calcium regulation in the early postmortem muscle. The poultry industry is still not at the point of using genetic marker(s); however, some recent work has revealed several potential markers. The review also discusses environmental factors such as antemortem stress and early postmortem processing practices (e.g. chilling rate) that can influence the development and severity of the PSE phenomenon. Some of these factors are known to cause protein denaturation at the early stage of postmortem and directly contribute to poor water-holding capacity and inferior texture in fresh meat and later in processed products. A newer hypothesis suggesting that variation in protein oxidation, in response to antemortem stress and early postmortem tissue environment, can contribute to development of PSE pork is also discussed. Finally, a few recommendations for future work are proposed.

Discharging older patients from home care: who decides and when?

Who is involved in the decisions to discharge patients from home care and how much lead-in time for planning is observed? How does the process of discharging patients from home care differ by reason for discharge? These questions are addressed in this study of 383 Medicare-funded patients discharged from home care agencies in central Ohio.

The specialty of the treating physician affects the likelihood of tumor-free resection margins for basal cell carcinoma: results from a multi-institutional retrospective study.

BACKGROUND: Basal cell carcinoma (BCC) is the most common cutaneous malignancy. Surgical experience and physician specialty may affect the outcome quality of surgical excision of BCC. METHODS: We performed a multicenter retrospective study of BCC excisions submitted to the respective Departments of Pathology at 4 major university medical centers. Our outcome measure was presence of histologic evidence of tumor present in surgical margins of excision specimens (incomplete excision). Clinician experience was defined as the number of excisions that a clinician performed during the study interval. The analytic sample pool included 1459 tumors that met all inclusion and exclusion criteria. Analyses included univariate and multivariate techniques involving the entire sample and separate subsample analyses that excluded 2 outlying dermatologists. RESULTS: Tumor was present at the surgical margins in 243 (16.6%) of 1459 specimens. A patient's sex, age, and tumor size were not significantly related to the presence of tumor in the surgical margin. Physician experience did not demonstrate a significant difference either in the entire sample (P <.09) or in the subsample analysis (P >.30). Tumors of the head and neck were more likely to be incompletely excised than truncal tumors in all the analyses (P <.03). Compared with dermatologists, otolaryngologists (P <.02) and plastic surgeons (P <.008) were more likely to incompletely excise tumors; however, subsample analysis for plastic surgeons found only a trend toward significance (P <.10). Dermatologists and general surgeons did not differ in the likelihood of performing an incomplete excision (P >.4). CONCLUSION: The physician specialty may affect the quality of care in the surgical management of BCC.

Emergence of resistance to clarithromycin during treatment of disseminated cutaneous Mycobacterium chelonae infection: case report and literature review.

Results of in vitro susceptibility studies and one clinical trial have led to recommendations of clarithromycin monotherapy for the treatment of disseminated cutaneous Mycobacterium chelonae infections. We describe the case of a 65-year-old woman, immunocompromised by the use of chronic steroid therapy, who developed disseminated cutaneous infection with M. chelonae and failed clarithromycin monotherapy due to the development of drug resistance. In the relapse isolate we document the presence of a single point mutation at position 2058 in the gene coding for 23S rRNA peptidyltransferase regions, a mutation previously implicated in the development of resistance to clarithromycin. Two susceptible control isolates lacked the mutation. Three additional reports in the literature of patients developing recurrent skin lesions with clarithromycin-resistant M. chelonae following initial response to monotherapy are summarized. We demonstrate that clarithromycin monotherapy in patients with disseminated cutaneous infections can lead to clarithromycin resistance and therapeutic failure associated with a single point mutation at position 2058 of 23S rRNA.

Driving-induced stress in urban college students.

Urban college student commuters (N = 407) were surveyed about their experiences with stress induced by driving. Of the participants 23.6% reported becoming angry at another driver more than once per day. They rated stress from other drivers as equal to the stress experienced during a college examination but gave slightly lower ratings to traffic congestion, road construction, and finding a parking place as sources of stress. Slow drivers, a child not restrained, and a vehicle following too closely were the highest rated annoying situations. Of participants, 21.6% had reported another driver to the police; nearly 22% said they carried a weapon for protection from other drivers (5.4% said a gun). Men were more than twice as likely as women to carry a weapon and three times as likely to carry a gun. Of the total sample, 19.1% feared being shot by another driver. Most participants (75.8%) said drivers were more aggressive and dangerous than they were five years ago.

A genetically encoded, fluorescent indicator for cyclic AMP in living cells.

Cyclic AMP controls several signalling cascades within cells, and changes in the amounts of this second messenger have an essential role in many cellular events. Here we describe a new methodology for monitoring the fluctuations of cAMP in living cells. By tagging the cAMP effector protein kinase A with two suitable green fluorescent protein mutants, we have generated a probe in which the fluorescence resonance energy transfer between the two fluorescent moieties is dependent on the levels of cAMP. This new methodology opens the way to the elucidation of the biochemistry of cAMP in vivo.

Property rights and privacy principles.

Healthcare consumers own their medical information. As paper medical folders become digital, protection of this private and confidential information falls to information specialists rather than the traditional care givers. On the basis of a nationwide market assessment study, the authors identify the key issues regarding protecting this personal digital property and outline the federal requirements stemming from the Health Insurance Portability and Accountability Act (HIPAA). Consumer informed consent over the use of specific medical data is a basic requirement, and is a concept supported by physicians and care givers who rely on consent to approve surgeries and treatment. The article concludes with a solution outline that places the patient in control of his or her personal information, meets security and privacy concerns, and facilitates the critical exchange of patient information among care givers.

A fluorescent reporter assay for the detection of ligands acting through Gi protein-coupled receptors.

Accompanying the advances in basic biology of G protein-coupled receptors (GPCRs) is the practical need among biopharmaceutical companies for sensitive assays to assess GPCR function, particularly formats that are compatible with high-throughput drug screening. Here we describe a novel cell-based assay format for the high-throughput detection of ligands for Gi protein-coupled receptors. Two Gi-GPCRs, mu-opioid receptor (mu-OPR) and 5-hydroxytryptamine receptor la (5HT1aR) are employed as model receptor targets. The key feature of this assay system is the isolation of stable, clonal Chinese hamster ovary (CHO) cell lines that carry three separate expression plasmids: (1) a chimeric Gq/i5 protein (which re-directs a negative Gi-type signal to a positive Gq-type response), (2) a given Gi-GPCR, and (3) a beta-lactamase (beta1a) reporter gene responsive to Gi-GPCR signaling. Cell-based assays built using this format show appropriate rank order of potency among a reference set of receptor agonist and antagonist compounds. Such assays are also robust, reliable, and can be used for industrial-scale applications such as high-throughput screening for drug leads.

Is arm span an accurate measure of height in young and middle-age adults?

Height is used to determine many important clinical measurements, but height may be difficult or impossible to measure accurately in some patients. The purpose of this study is to determine the accuracy of arm span as a measure of height in young and middle-age adults. A sample of 83 people between the ages of 20 and 61 years participated in this anthropometric study. Height and arm span were measured with a metal rule. A prediction equation was derived from regression analysis. Arm span is a valid measure of height in young and middle-age adults, and the accuracy is improved when using the prediction equation.

John Dewey's unknown critique of marginal utility doctrine: instrumentalism, motivation, and values.

During the late nineteenth century, marginal utility theory became the dominant ideology of the new academic discipline of economics. This article explicates and discusses previously unexamined lecture notes prepared in 1913 by John Dewey on marginal utility doctrine. After briefly characterizing the state of marginal utility doctrine, Dewey's criticisms are shown to derive from his instrumentalism and general theory of value. In Dewey's view, marginalism privatized value and by doing so induced moral agnosticism, a condition of permanently suspended judgment regarding individual and social needs that was likely to undermine the foundations of a democratic community since it immunizes value against collective appraisal by public bodies. Moreover, while marginal utility theory represented a serious concerted attempt to deal with substantive problems of value in economics and the economy, to Dewey it was ultimately a form of apologetics for the existing mode of social relations.

The analysis of the data for two-way contingency tables.

One of the best ways, if not the best way, to analyze data displayed in a two-way contingency table is to use a method originally due to Williams (1952) and later embellished upon by Guttman (1971) and others. This method applies the principles of canonical correlation analysis to contingency table data and obviates the need for the a priori specification of scale values for the two variables whose relationship is explored. In this article the method is described and compared with other approaches, and several examples of its application are provided.

A genome-wide functional assay of signal transduction in living mammalian cells.

We describe a genome-wide functional assay for rapid isolation of cell clones and genetic elements responsive to specific stimuli. A promoterless beta-lactamase reporter gene was transfected into a human T-cell line to generate a living library of reporter-tagged clones. When loaded with a cell-permeable fluorogenic substrate, the cell library simultaneously reports the expression of a large number of endogenous genes. Flow cytometry was used to recover individual clones whose reporter-tagged genes were either induced or repressed following T-cell activation. Responsive clones were expanded and analyzed pharmacologically to identify patterns of regulation associated with specific genes. Although demonstrated using T cells, the genomic assay could be applied to map downstream transcriptional consequences for any propagating cell line in response to any stimulus of interest.

MR imaging of symptomatic osteochondromas with pathological correlation.

OBJECTIVE: To demonstrate the value of MR imaging in the diagnosis and differentiation of the various symptomatic complications of osteochondromas, providing pathological correlation with emphasis on the usefulness of MR imaging as a single imaging modality in these patients. DESIGN: We retrospectively reviewed all MR examinations of clinically symptomatic osteochondromas (30 patients) performed at our institution between March 1990 and October 1997. PATIENTS: Thirty patients had clinically symptomatic osteochondromas during the study period. Twenty patients were male and 10 were female. There were five cases of multiple osteochondromatosis. Pathological correlation was available in 24 patients. RESULTS AND CONCLUSION: Symptomatic complications included fracture (7%), osseous deformity limiting range of motion (23%), vascular injury (7%), neurological compromise (10%), bursa formation (27%) and malignant transformation (27%). MR imaging was able to diagnose or suggest the etiology for the clinical symptomatology in all cases, demonstrating that it is an ideal imaging modality in the diagnostic evaluation of symptomatic complications of osteochondromas and often avoids the need for further imaging.