Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field.

Muonic helium atom hyperfine structure (HFS) measurements are a sensitive tool to test the three-body atomic system and bound-state quantum electrodynamics theory, and determine fundamental constants of the negative muon magnetic moment and mass. The world's most intense pulsed negative muon beam at the Muon Science Facility of the Japan Proton Accelerator Research Complex allows improvement of previous measurements and testing further CPT invariance by comparing the magnetic moments and masses of positive and negative muons (second-generation leptons). We report new ground-state HFS measurements of muonic helium-4 atoms at a near-zero magnetic field, performed for the first time using a small admixture of CH_{4} as an electron donor to form neutral muonic helium atoms efficiently. Our analysis gives Δν=4464.980(20) MHz (4.5 ppm), which is more precise than both previous measurements at weak and high fields. The muonium ground-state HFS was also measured under the same conditions to investigate the isotopic effect on the frequency shift due to the gas density dependence in He with CH_{4} admixture and compared with previous studies. Muonium and muonic helium can be regarded as light and heavy hydrogen isotopes with an isotopic mass ratio of 36. No isotopic effect was observed within the current experimental precision.

Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon.

To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of the 5g-4f and 5f- 4d transitions (BSQED contribution of 2.4 and 5.2 eV, respectively) of muonic neon atoms in the low-pressure gas phase without bound electrons. Muonic atoms have been recently proposed as an alternative to few-electron high-Z ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined the 5g_{9/2}- 4f_{7/2} transition energy to be 6297.08±0.04(stat)±0.13(syst) eV using superconducting transition-edge sensor microcalorimeters (5.2-5.5 eV FWHM resolution), which agrees well with the most advanced BSQED theoretical prediction of 6297.26 eV.

Deexcitation Dynamics of Muonic Atoms Revealed by High-Precision Spectroscopy of Electronic K X Rays.

We observed electronic K x rays emitted from muonic iron atoms using superconducting transition-edge sensor microcalorimeters. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic Kα and Kß x rays together with the hypersatellite K^{h}α x rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the L-shell electrons, accompanied by electron side feeding. Assisted by a simulation, these data clearly reveal the electronic K- and L-shell hole production and their temporal evolution on the 10-20 fs scale during the muon cascade process.

Controlling Near-Surface Ni Composition in Octahedral PtNi(Mo) Nanoparticles by Mo Doping for a Highly Active Oxygen Reduction Reaction Catalyst.

We report and study the translation of exceptionally high catalytic oxygen electroreduction activities of molybdenum-doped octahedrally shaped PtNi(Mo) nanoparticles from conventional thin-film rotating disk electrode screenings (3.43 ± 0.35 A mgPt-1 at 0.9 VRHE) to membrane electrode assembly (MEA)-based single fuel cell tests with sustained Pt mass activities of 0.45 A mgPt-1 at 0.9 Vcell, one of the highest ever reported performances for advanced shaped Pt alloys in real devices. Scanning transmission electron microscopy with energy dispersive X-ray analysis (STEM-EDX) reveals that Mo preferentially occupies the Pt-rich edges and vertices of the element-anisotropic octahedral PtNi particles. Furthermore, by combining in situ wide-angle X-ray spectroscopy, X-ray fluorescence, and STEM-EDX elemental mapping with electrochemical measurements, we finally succeeded to realize high Ni retention in activated PtNiMo nanoparticles even after prolonged potential-cycling stability tests. Stability losses at the anodic potential limits were mainly attributed to the loss of the octahedral particle shape. Extending the anodic potential limits of the tests to the Pt oxidation region induced detectable Ni losses and structural changes. Our study shows on an atomic level how Mo adatoms on the surface impact the Ni surface composition, which, in turn, gives rise to the exceptionally high experimental catalytic ORR reactivity and calls for strategies on how to preserve this particular surface composition to arrive at performance stabilities comparable with state-of-the-art spherical dealloyed Pt core-shell catalysts.

Cation Effects on the Acidic Oxygen Reduction Reaction at Carbon Surfaces.

Hydrogen peroxide (H2O2) is a widely used green oxidant. Until now, research has focused on the development of efficient catalysts for the two-electron oxygen reduction reaction (2e- ORR). However, electrolyte effects on the 2e- ORR have remained little understood. We report a significant effect of alkali metal cations (AMCs) on carbons in acidic environments. The presence of AMCs at a glassy carbon electrode shifts the half wave potential from -0.48 to -0.22 VRHE. This cation-induced enhancement effect exhibits a uniquely sensitive on/off switching behavior depending on the voltammetric protocol. Voltammetric and in situ X-ray photoemission spectroscopic evidence is presented, supporting a controlling role of the potential of zero charge of the catalytic enhancement. Density functional theory calculations associate the enhancement with stabilization of the *OOH key intermediate as a result of locally induced field effects from the AMCs. Finally, we developed a refined reaction mechanism for the H2O2 production in the presence of AMCs.

MMP-9 haplotypes and carotid artery atherosclerosis: an association study introducing a novel multicolour multiplex RealTime PCR protocol.

BACKGROUND: Among other matrix metalloproteinases (MMPs), gelatinase B (MMP-9) is discussed to be associated with the pathogenesis of vascular diseases. Two single nucleotide polymorphisms (SNPs) of the MMP-9 gene, C-1562T in the promoter region and a G/A transition in exon 6 (R + 279Q), have been addressed in previous association studies which, however, produced conflicting results. MATERIAL AND METHODS: A novel multiplex RealTime PCR protocol for the fast and simultaneous detection of both polymorphisms is presented, which was used for genotyping 1737 participants of a prospective study investigating genetic factors influencing the progression of atherosclerosis. RESULTS: Haplotype analysis revealed -1562C/+279Q as the major haplotype in this population. Allelic distribution of the C-1562T polymorphism was consistent with data published for similar cohorts; however, we found that R + 279Q allelic distribution appears to vary significantly among Caucasian populations. Considering clinical data available from 1487 participants, we found significant associations between the presence of atherosclerotic plaque and the CA-haplotype in men (P = 0.028, phi = 0.08), and between the AG variant of exon 6 and common carotid artery intima-media thickness (CIMT) in women (P = 0.004, Eta(2) = 0.019). CONCLUSIONS: In summary, our results demonstrate associations of MMP-9 genotypes with different stages of carotid atherosclerosis.

Preparation of ortho-para ratio controlled D2 gas for muon-catalyzed fusion.

A negative muon in hydrogen targets, e.g., D2 or D-T mixture, can catalyze nuclear fusions following a series of atomic processes involving muonic hydrogen molecular formation (muon-catalyzed fusion, muCF). The ortho-para state of D2 is a crucial parameter not only for enhancing the fusion rate but also to precisely investigate various muonic atom processes. We have developed a system for controlling and measuring the ortho-para ratio of D2 gas for muCF experiments. We successfully collected para-enriched D2 without using liquid-hydrogen coolant. Ortho-enriched D2 was also obtained by using a catalytic conversion method with a mixture of chromium oxide and alumina. The ortho-para ratio of D2 gas was measured with a compact Raman spectroscopy system. We produced large volume (5-30 l at STP), high-purity (less than ppm high-Z contaminant) D2 targets with a wide range of ortho-para ratios (ortho 20%-99%). By using the ortho-para controlled D2 in muCF experiments, we observed the dependence of muCF phenomena on the ortho-para ratio.

Two domains of interaction with calcium binding proteins can be mapped using fragments of calponin.

Native calponin is able to bind 2 mol of calcium binding protein (CaBP) per mole calponin. This study extends this observation to define the 2 domains of interaction, one of which is near the actin binding site, and the other in the amino-terminal region of calponin. Also, the first evidence for a differentiation in the response of calponin to interaction with caltropin versus calmodulin is demonstrated. The binding of caltropin to cleavage and recombinant fragments of calponin was determined by 3 techniques: tryptophan fluorescence of the fragments, CD measurements to determine secondary structure changes, and analytical ultracentrifugation. In order to delineate the sites of interaction, 3 fragments of calponin have been studied. From a cyanogen bromide cleavage of calponin, residues 2-51 were isolated. This fragment is shown to bind to CaBPs and the affinity for caltropin is slightly higher than that for calmodulin. A carboxyl-terminal truncated mutant of calponin comprising residues 1-228 (CP 1-228) has been produced by recombinant techniques. Analytical ultracentrifugation has shown that CP 1-228, like the parent calponin, is able to bind 2 mol of caltropin per mol of 1-228 in a Ca(2+)-dependent fashion, indicating that there is a second site of interaction between residues 52-228. Temperature denaturation of the carboxyl-terminal truncated fragment compared with whole calponin show that the carboxyl-terminal region does not change the temperature at which calponin melts; however, there is greater residual secondary structure with whole calponin versus the fragment. A second mutant produced through recombinant techniques comprises residues 45-228 and is also able to bind caltropin, thus mapping the location of the second site of interaction to near the actin binding site.

Mammalian calponin. Identification and expression of genetic variants.

Calponin is a smooth muscle specific, actin-, tropomyosin- and calmodulin-binding protein thought to be involved in some way in the regulation or modulation of contraction. Here we describe the cloning and bacterial expression of two calponin species from murine and porcine smooth muscle tissues. Primary and secondary structural analyses of the deduced amino acid sequences revealed a high degree of homology to avian calponin with the exception of a short and variable C-terminal segment. The sequence data demonstrate that the two mammalian calponin variants do not arise via alternative splicing but are encoded by different genes.

Variable and constant regions in the C-terminus of vinculin and metavinculin. Cloning and expression of fragments in E. coli.

Metavinculin differs from vinculin in having an additional insert of 68 to 79 amino acids in length in the C-terminal half of the molecule. Cross-species comparison of metavinculin sequences from pig, man, chicken and frog reveals a division of the insert into two parts: the first variable and the second highly conserved. The longest insert, 79 amino acids, was found in Xenopus laevis. Three different C-terminal constructs of vinculin and metavinculin over-expressed in E. coli could be purified by column chromatography. Two-dimensional gel electrophoresis and peptide analysis revealed pI values between 8.35 and 10.25 for the recombinant proteins. Biochemical and structural features of the metavinculin-specific sequence and the conserved vinculin/metavinculin carboxy-terminus are discussed.

Calponin reduces shortening velocity in skinned taenia coli smooth muscle fibres.

Calponin (4.1-5.9 microM, pig stomach) inhibited maximal shortening velocity (Vmax) by 20-25% with only minor influence on force in skinned smooth muscle from guinea-pig taenia coli activated at different Ca2+ levels and with thiophosphorylation. Similar results were obtained with a fragment of the N-terminal 1-228 amino acids engineered using a mouse cDNA construct (5.4 microM). Both the native calponin and the fragment inhibited actin filament sliding in a graded manner in an in vitro motility assay. We conclude that calponin influences the kinetics of the actin-myosin interaction in the organised smooth muscle contractile system and that engineered fragments of calponin can be used to probe its action in muscle fibres. The effects can be due to an introduction of an internal load during filament sliding, possibly by decreasing the detachment rates and increasing the cross-bridge time spent in the attached state.

Controlled clinical trial of pediatric telephone protocols.

A randomized clinical trial of pediatric protocols administered by health assistants demonstrated an alternate method of handling telephone complaints in a large emergency room. The new system advised a higher medical examination rate than the current system in the emergency room probably bacause the current system has deficits with respect to collecting necessary information and making explicit decisions. This higher rate of recommended visits demonstrated in the emergency room was not confirmed in the two pediatric primary-care settings in which the protocol system was also tested. In addition to this use, the telephone protocols may also be useful in training medical and nursing students, in handling telephone complaints similar to a poison control center, in triaging problems in a rural or emergency medical service, and in providing a record of the telephone call.

Development and field testing of protocols for the management of pediatric telephone calls: protocols for pediatric telephone calls.

Although telephone calls comprise almost one fourth of all childhood patient-physician contacts, the content of telephone care is not emphasized in most educational and service programs. In response to the need to improve management of telephone calls to our pediatric emergency room, we developed 28 protocols to deal with the 25 most common complaints presented by phone. This paper describes the content of these protocols, the training of the health assistants who administered them, and the measures we took to assure their safety and general utility in pediatric practice settings. The study demonstrates the feasibility of an organized system for telephone care based on protocols which include: (1) basic data to be collected for each chief complaint category; (2) a range of appropriate dispositions; and (3) advice for home management when the patient does not require an immediate medical visit. Potential uses of these protocols for medical and nursing education and for clinical service needs are discussed.

Demonstrating the value of occupational and environmental health programs.

As the saying goes, "Just do it." If the occupational and environmental health service has never been formally evaluated, there is no better time than now. Company management may change at any time. A new administrator may want an accounting of the department's value. Do not wait for that time and be in a position where you have to put something together instantly. Be proactive--start the process now.

Smoking cessation programs in the workplace. Review and recommendations for occupational health nurses.

The worksite offers occupational health nurses unique opportunities to assist workers in their smoking cessation efforts. For nurses to be effective in this endeavor, they must be knowledgeable about the various quit smoking strategies that have met with some success. Based on the review of the research, there is no "magic bullet" to offer smokers who want to quit. Occupational health nurses have an opportunity, therefore, to use multiple approaches and design programs to fit the specific needs of the smokers in their practice. Published reports of nurses' involvement in workplace smoking cessation programs are sparse. It is crucial that occupational health nurses spearhead smoking cessation efforts at the workplace and communicate the results of these enterprises.

Depression in the workplace. Impact on employees.

Given the current high incidence of depression, occupational health nurses in all work settings are likely to encounter many employees who suffer from some form of depression. Depression has the highest medical benefit costs for all behavioral conditions and results in more days of disability than chronic medical conditions such as heart disease, hypertension, diabetes, and lower back pain. Advances in understanding the physiologic changes in the brain which cause depression have lead to development of effective psychopharmacologic agents for treatment. Depressed individuals have the most positive responses with a combination of medication and psychotherapy. Nurses need to assist affected employees to obtain optimal mental health care so they may remain as functional as possible, thereby diminishing the detrimental effects of the illness.

Perceived psychological stress and upper extremity cumulative trauma disorders.

This report presents data exploring the relationship between perceived psychological stress and several variables implicated in the etiology of upper extremity cumulative trauma disorders (UECTDs). The sample was 354 workers from three different manufacturing companies. The primary job exposure for the subjects was that they were engaged in jobs that involved repetitious movements of the upper extremities, primarily of the hands and arms. Data collection included a detailed health history, a comprehensive physical examination of the upper extremities, limited electrodiagnostic testing, Cohen's Perceived Stress Scale, Karasek's Job Content Questionnaire, demographic information, and a measurement of repetition. Descriptive analyses, analysis of variance, correlational analyses, and multiple linear regression were used to examine the data. Perceived stress, as measured in this study, was only weakly associated with repetition, job dissatisfaction, and subjective complaints related to UECTDs. In addition, factors generally accepted as related to UECTDs (e.g., repetition, female gender, hormonal influences, and existing medical conditions) were not robust predictors of perceived stress. The major limitation is related to the measurement of perceived psychological stress. Like most psychosocial phenomena, perceived stress is a complex construct, one that is difficult to measure and correlate with health outcomes. Further research is necessary to examine what role, if any, perceived stress may have in the etiology of UECTDs.