Day-to-day reliability of basal heart rate and short-term and ultra short-term heart rate variability assessment by the Equivital eq02+ LifeMonitor in US Army soldiers.

INTRODUCTION: The present study determined the (1) day-to-day reliability of basal heart rate (HR) and HR variability (HRV) measured by the Equivital eq02+ LifeMonitor and (2) agreement of ultra short-term HRV compared with short-term HRV. METHODS: Twenty-three active-duty US Army Soldiers (5 females, 18 males) completed two experimental visits separated by >48 hours with restrictions consistent with basal monitoring (eg, exercise, dietary), with measurements after supine rest at minutes 20-21 (ultra short-term) and minutes 20-25 (short-term). HRV was assessed as the SD of R-R intervals (SDNN) and the square root of the mean squared differences between consecutive R-R intervals (RMSSD). RESULTS: The day-to-day reliability (intraclass correlation coefficient (ICC)) using linear-mixed model approach was good for HR (0.849, 95% CI: 0.689 to 0.933) and RMSSD (ICC: 0.823, 95% CI: 0.623 to 0.920). SDNN had moderate day-to-day reliability with greater variation (ICC: 0.689, 95% CI: 0.428 to 0.858). The reliability of RMSSD was slightly improved when considering the effect of respiration (ICC: 0.821, 95% CI: 0.672 to 0.944). There was no bias for HR measured for 1 min versus 5 min (p=0.511). For 1 min measurements versus 5 min, there was a very modest mean bias of -4 ms for SDNN and -1 ms for RMSSD (p≤0.023). CONCLUSION: When preceded by a 20 min stabilisation period using restrictions consistent with basal monitoring and measuring respiration, military personnel can rely on the eq02+ for basal HR and RMSSD monitoring but should be more cautious using SDNN. These data also support using ultra short-term measurements when following these procedures.

Empirical Determination of the Bohr-Weisskopf Effect in Cesium and Improved Tests of Precision Atomic Theory in Searches for New Physics.

The finite distribution of the nuclear magnetic moment across the nucleus gives a contribution to the hyperfine structure known as the Bohr-Weisskopf (BW) effect. We have obtained an empirical value of -0.24(18)% for this effect in the ground and excited s states of atomic ^{133}Cs. This value is found from historical muonic-atom measurements in combination with our muonic-atom and atomic many-body calculations. The effect differs by 0.5% in the hyperfine structure from the value found using the uniform magnetization distribution, which has been commonly employed in the precision heavy-atom community over the last several decades. We also deduce accurate values for the BW effect in other isotopes and states of cesium. These results enable cesium atomic wave functions to be tested in the nuclear region at an unprecedented 0.2% level, and are needed for the development of precision atomic many-body methods. This is important for increasing the discovery potential of precision atomic searches for new physics, in particular for atomic parity violation in cesium.

Nuclear Magnetic Moments of Francium-207-213 from Precision Hyperfine Comparisons.

We report a fourfold improvement in the determination of nuclear magnetic moments for neutron-deficient francium isotopes 207-213, reducing the uncertainties from 2% for most isotopes to 0.5%. These are found by comparing our high-precision calculations of hyperfine structure constants for the ground states with experimental values. In particular, we show the importance of a careful modeling of the Bohr-Weisskopf effect, which arises due to the finite nuclear magnetization distribution. This effect is particularly large in Fr and until now has not been modeled with sufficiently high accuracy. An improved understanding of the nuclear magnetic moments and Bohr-Weisskopf effect are crucial for benchmarking the atomic theory required in precision tests of the standard model, in particular atomic parity violation studies, that are underway in francium.

Search for a Variation of the Fine Structure Constant around the Supermassive Black Hole in Our Galactic Center.

Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond general relativity and the standard model motivated by unification theories and models of dark matter and dark energy. We propose a new way to search for a variation of the fine-structure constant using measurements of late-type evolved giant stars from the S star cluster orbiting the supermassive black hole in our Galactic Center. A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct estimate of a variation of the fine structure constant between the star's location and Earth. Using spectroscopic measurements of five stars, we obtain a constraint on the relative variation of the fine structure constant below 10^{-5}. This is the first time a varying constant of nature is searched for around a black hole and in a high gravitational potential. This analysis shows new ways the monitoring of stars in the Galactic Center can be used to probe fundamental physics.

Ionization of Atoms by Slow Heavy Particles, Including Dark Matter.

Atoms and molecules can become ionized during the scattering of a slow, heavy particle off a bound electron. Such an interaction involving leptophilic weakly interacting massive particles (WIMPs) is a promising possible explanation for the anomalous 9σ annual modulation in the DAMA dark matter direct detection experiment [R. Bernabei et al., Eur. Phys. J. C 73, 2648 (2013)]. We demonstrate the applicability of the Born approximation for such an interaction by showing its equivalence to the semiclassical adiabatic treatment of atomic ionization by slow-moving WIMPs. Conventional wisdom has it that the ionization probability for such a process should be exponentially small. We show, however, that due to nonanalytic, cusplike behavior of Coulomb functions close to the nucleus this suppression is removed, leading to an effective atomic structure enhancement. We also show that electron relativistic effects actually give the dominant contribution to such a process, enhancing the differential cross section by up to 1000 times.

Limiting P-odd interactions of cosmic fields with electrons, protons, and neutrons.

We propose methods for extracting limits on the strength of P-odd interactions of pseudoscalar and pseudovector cosmic fields with electrons, protons, and neutrons, by exploiting the static and dynamic parity-nonconserving amplitudes and electric dipole moments they induce in atoms. Candidates for such fields are dark matter (including axions) and dark energy, as well as several more exotic sources described by Lorentz-violating standard model extensions. Atomic calculations are performed for H, Li, Na, K, Rb, Cs, Ba(+), Tl, Dy, Fr, and Ra(+). From these calculations and existing measurements in Dy, Cs, and Tl, we constrain the interaction strengths of the parity-violating static pseudovector cosmic field to be 7 × 10(-15) GeV with an electron, and 3 × 10(-8) GeV with a proton.

Relationship between glycine transporter 1 inhibition as measured with positron emission tomography and changes in cognitive performances in nonhuman primates.

Several lines of evidence suggest that schizophrenia is associated with deficits in glutamatergic transmission at the N-methyl-d-aspartate (NMDA) receptors. Glycine is a NMDA receptor co-agonist, and extracellular levels of glycine are regulated in the forebrain by the glycine type-1 transporters (GlyT-1). GlyT-1 inhibitors elevate extracellular glycine and thus potentiate NMDA transmission. This mechanism represents a promising new avenue for the treatment of schizophrenia. Here, the recently introduced positron emission tomography radiotracer [11C]GSK931145 was used to quantify the relationship between occupancy of GlyT-1 by a GlyT-1 inhibitor, Org 25935, and its impact on spatial working memory performances in rhesus monkeys. The effect of Org 25935 on working memory was assessed both in control conditions and during a state of relative NMDA hypofunction induced by ketamine administration, at a dose selected for each animal to reduce task performance by about 50%. Under control conditions, Org 25935 had no effect on working memory at GlyT-1 occupancies lower than 75% and significantly impaired working memory at occupancies higher than 75%. Under ketamine conditions, Org 25935 reversed the deficit in working memory induced by ketamine and did so optimally in the 40-70% GlyT-1 occupancy range. The results confirm the efficacy of this mechanism to correct working memory deficits associated with NMDA hypofunction. These data also suggest the existence of an inverted-U dose-response curve in the potential therapeutic effect of this class of compounds.

Cancer cachexia decreases specific force and accelerates fatigue in limb muscle.

Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative soleus is also important for normal locomotion, we further performed a fatigue trial in the soleus and found that the decrease in relative force was greater and more rapid in solei from C-26 mice compared to controls. These data demonstrate that severe cancer cachexia causes profound muscle weakness that is not entirely explained by the muscle atrophy. In addition, cancer cachexia decreases the fatigue resistance of the soleus muscle, a postural muscle typically resistant to fatigue. Thus, specifically targeting contractile dysfunction represents an additional means to counter muscle weakness in cancer cachexia, in addition to targeting the prevention of muscle atrophy.

Reduced immunolabelling of a porcine oocyte membrane protein reflects reduced fertilizability of porcine oocytes following elevated ambient temperature.

Decreased fertility in pigs is a common occurrence during summer months. An objective of the current experiments was to evaluate if elevated ambient temperature altered the oocyte plasma membrane including potential receptors for sperm. This would potentially contribute to reduced fertilizability. Treated gilts were exposed in vivo to 32 degrees C for 12 h per day and 20 degrees C for the remaining 12 h per day for 7 days; control gilts were exposed to 22 degrees C for 12 h and 20 degrees C for the remaining 12 h each day. Cumulus-oocyte complexes were also aspirated from ovaries obtained from gilts maintained at thermoneutral ambient temperature and matured in vitro at 38.5 degrees C or 40 degrees C. Relative abundance of a porcine oocyte membrane protein was examined by intensity of immunolabelling of the in vivo and in vitro matured oocytes evaluated with confocal microscopy; fertilizability of the in vitro matured oocytes was evaluated in in vitro fertilization assays. Oocytes obtained from gilts exposed to elevated ambient temperature for 7 days had reduced immunolabelling compared with oocytes from control gilts (p < 0.05). Similarly, oocytes matured in vitro for 44 h at elevated ambient temperature had reduced immunolabelling and reduced fertilizability compared with oocytes matured at 38.5 degrees C (p < 0.01 and p < 0.05). These results suggest porcine oocyte quality is reduced by elevated ambient temperature and immunolabelling of oocytes with antibodies to specific membrane proteins may be effective to evaluate some aspects of oocyte quality.

Comparison between cefotaxime and a combination of benzylpenicillin and cloxacillin as an antibiotic prophylaxis in cardiac surgery with cardio-pulmonary bypass.

In a prospective randomized trial, 422 patients undergoing elective cardiac surgery with cardiopulmonary bypass were studied for comparing two types of prophylactic antibiotic treatment. One group, 204 patients, received 4 doses of cefotaxime for 2 days. The other group, 198 patients, received 6 doses of benzylpenicillin combined with cloxacillin for 3 days. Sixty percent received the planned cefotaxime prophylaxis (CTX), while 43.4% received the planned combined benzylpenicillin with cloxacillin prophylaxis (BPC). This was because several patients in both groups required additional antibiotics for treatment of high fever (39.7%, CTX-ADD, in the cefotaxime group compared to 56.6%, BPC-ADD in the other group (p less than 0.01). The overall infection rate in the groups receiving the planned prophylaxis was significantly lower (4.1%) in the CTX-group compared to the 14% in the BPC-group (p less than 0.05). Early infections (less than 14 days) were lower in the groups CTX-group (3%) compared to the BPC-group (16%) (p less than 0.046). In the groups receiving additional antibiotics for fever (CTX-ADD and BPC-ADD), the former had a significantly lower number of infections, 16 compared to 23, in the latter group (p less than 0.01). There were significantly fewer early infections in the CTX-ADD compared to the BPC-ADD group (4 vs. 10 respectively, p less than 0.01). No deep infections were seen when CTX or CTX-ADD was used, while 6 deep wound infections occurred when BPC or BPC-ADD was used. The lowest rate of positive cultures of bacteria was seen in the CTX-group (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)