An improved limit on the neutrinoless double-electron capture of 36Ar with GERDA

The GERmanium Detector Array (Gerda) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of 36 Ar, a candidate isotope for the two-neutrino double-electron capture (2ν ECEC) and therefore for the neutrinoless double-electron capture (0ν ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0ν ECEC of 36 Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the Gerda germanium detectors. We searched for the 36 Ar 0ν ECEC with Gerda data, with a total live time of 4.34 year (3.08 year accumulated during Gerda Phase II and 1.26 year during Gerda Phase I). No signal was found and a 90% CL lower limit on the half-life of this process was established T 1 / 2 > 1.5 · 10 22  year.

Supplementary Information

The online version contains supplementary material available at 10.1140/epjc/s10052-023-12280-6.

Final Results of GERDA on the Two-Neutrino Double-β Decay Half-Life of ^{76}Ge

We present the measurement of the two-neutrino double-β decay rate of ^{76}Ge performed with the GERDA Phase II experiment. With a subset of the entire GERDA exposure, 11.8 kg yr, the half-life of the process has been determined: T_{1/2}^{2ν}=(2.022±0.018_{stat}±0.038_{syst})×10^{21}  yr. This is the most precise determination of the ^{76}Ge two-neutrino double-β decay half-life and one of the most precise measurements of a double-β decay process. The relevant nuclear matrix element can be extracted: M_{eff}^{2ν}=(0.101±0.001).

Search for tri-nucleon decays of 76Ge in GERDA

We search for tri-nucleon decays of 76 Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to 73 Cu, 73 Zn, and 73 Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of 73 Ga to 73 Ge (stable). We search for the 73 Ga decay exploiting the fact that it dominantly populates the 66.7 keV 73 m Ga state with half-life of 0.5 s. The nnn-decays of 76 Ge that proceed via 73 m Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2× 1026  yr  (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.

Liquid argon light collection and veto modeling in GERDA Phase II

The ability to detect liquid argon scintillation light from within a densely packed high-purity germanium detector array allowed the Gerda experiment to reach an exceptionally low background rate in the search for neutrinoless double beta decay of76 Ge. Proper modeling of the light propagation throughout the experimental setup, from any origin in the liquid argon volume to its eventual detection by the novel light read-out system, provides insight into the rejection capability and is a necessary ingredient to obtain robust background predictions. In this paper, we present a model of the Gerda liquid argon veto, as obtained by Monte Carlo simulations and constrained by calibration data, and highlight its application for background decomposition.

Simulations and measurements of bilamellar streak tubes

Particle-in-cell simulations of a picosecond-resolution bilamellar streak tube are described, and the results are compared to measurements of key specifications. A novel laser diode setup with a small focal spot has been used to investigate the sensitive width of the photocathode, a previously unpublished parameter. Simulations have shown that the tubes, while performing at high spatiotemporal resolution, have electron efficiencies of just 1.6% due to the action of the temporal focusing electrode, contributing to an effective dynamic range of around 10. The virtual photocathode created by this electrode was predicted to be 144 µm, in excellent agreement with the measured width of 136 µm. A simple method to improve the tube's dynamic range by narrowing the slit width is investigated and shown to have a modest simulated improvement.

Negative impact of socioeconomic deprivation on clinical outcomes after cryoablation for atrial fibrillation: 18-month study

Background

Lower socioeconomic status has also been shown to associate with higher incidence of atrial fibrillation (AF), increased mortality and morbidity. However, the impact of socioeconomic deprivation on clinical outcomes post AF cryoablation has yet to be investigated.

Aim

To assess the impact of socioeconomic deprivation (as categorised by Scottish Index of Multiple Deprivation, SIMD) on the medical management and clinical outcomes of patients with AF post cryoablation.

Methods

A retrospective study of paroxysmal or persistent AF patients after cryoablation. Parameters included basic demographics, weight, past medical history (hypertension, heart failure, diabetes, stroke, myocardial infarction, sleep apnoea) and alcohol misuse. Medical treatment post ablation (Beta blocker, calcium channel blocker, flecainide, amiodarone, dronaderone, sotolol, anticoagulant use) were also recorded.

Socioeconomic deprivation index, as per SIMD was recorded (1 – most deprived and 10 – least deprived), and accordingly placed into quintile (SIMD 1–2,3–4,5–6,7–8, 9–10). Follow-up for 18 months.

Clinical outcome assessed was rate of readmission for symptomatic AF, rate of heart failure admission, stroke, bleeding diathesis and all-cause mortality.

Results

383 patients were identified: 78 from the lowest quintile (SIMD 1–2), 68 (SIMD 3–4), 64 (SIMD 5–6), 62 (SIMD 7–8), and 111 from the highest quintile (SIMD 9–10). No statistical difference exists between age, gender or weight. Lowest socioeconomic quintile has higher incidence of heart failure (p=0.006) and hypertension (p=0.005) but other past medical history was no different. No difference in incidence of alcohol misuse.

Medicine prescription was not different. Echo features: left ventricular function, atrial size and valvular dysfunction were not different between all groups.

18 months follow-up demonstrated that both readmission for symptomatic documented AF and recurrence of symptoms at 18 months were higher among patients of lowest socioeconomic quintile (Keplan Meier plot, p=0.014 and p=0.006 respectively). Stepwise multiple regression analysis also confirmed multiple socioeconomic deprivation as an independent predictor for more adverse clinical outcome (p=0.02).

Risk of symptom recurrence at 18 months in patients from the least deprived background is less than one third as compared to the ones from the most deprived background (Odd-ratio 0.32 (0.17 - 0.59))

Risk of readmission for AF in patients from the wealthiest socioeconomic group is also less than a third as compared to those of most deprived social group (Odd-ratio 0.31 (95% CI 0.15–0.61)).

Other clinical outcomes including risk of admissions for heart failure, stroke, bleeding diathesis and all-cause mortality was not statistically different across all groups.

Summary

After cryoablation, patients from the lowest socioeconomic group are more likely to experience symptoms recurrence and readmission for symptomatic AF

Funding Acknowledgement

Type of funding sources: None.

Same day CT angiography in a nurse-led Rapid Access Chest Pain Clinic

Funding Acknowledgements

None

Background

Rapid Access Chest Pain clinics (RACPCs) were established in the UK in 2000 following the publication of the National Service Framework for Coronary Heart Disease. Patients underwent an exercise test (ETT) in the clinic as part of a ‘one-stop’ protocol with follow-up only if further investigation was required. In 2010, the National Institute for Health and Care Excellence (NICE) produced guidelines for the assessment and diagnosis of chest pain of recent onset (CG95),  replacing the recommendation for ETT with non-invasive functional testing for patients with an intermediate pre-test probability of coronary artery disease (CAD), necessitating multiple appointments to evaluate the patient’s symptoms. The guidelines were updated in 2016, with a new recommendation that patients with atypical or typical chest pain should undergo CT coronary angiography (CTCA) as the first diagnostic test.

Purpose

The aim of this study was to investigate the feasibility and potential benefit of performing same -day CTCA in the RACPC.

Method

From November 2016 all patients with atypical or typical chest pain attending the RACPC at this tertiary cardiac centre were referred for CTCA unless alternative investigation was clinically indicated.  From February 2018, same day CTCA was offered to some patients. Up to two scans could be performed in each clinic, which was increased to up to three in June 2018.

Results

A total of 985 patients were seen in the nurse-led clinic between 12/02/2018 and 30/11/2019. 473 patients were referred for CTCA (48.0%) and 314 scans were carried out in the clinic (66.4%). Of those scans carried out in clinic, 128 patients had a CTCA which showed no evidence of CAD (40.8%) and 34.4% of scans showed non-obstructive CAD. In 18.2% of patients, the CTCA showed significant CAD and in 21 patients (6.7%) the scan was inconclusive. Patient with inconclusive scans underwent further testing which was negative in all cases. The outcome for patients with significant CAD (57 patients) is shown in the table.

Conclusion

CTCA on the same day as the RACPC appointment is feasible and facilitates rapid further investigation and treatment of patients with potentially significant CAD. It also enables patients with non-significant or no CAD to be reassured that their symptoms are unlikely to be cardiac which will reduce anxiety and allow timely investigation of other causes of the chest pain. Nurses need training in the risks of radiation in order to be able to request the scans and enable the clinic to be nurse-led.

A feasibility service evaluation of screening and treatment of group A streptococcal pharyngitis in community pharmacies

OBJECTIVES

The UK 5 year antimicrobial resistance strategy recognizes the role of point-of-care diagnostics to identify where antimicrobials are required, as well as to assess the appropriateness of the diagnosis and treatment. A sore throat test-and-treat service was introduced in 35 community pharmacies across two localities in England during 2014-15.

METHODS

Trained pharmacy staff assessed patients presenting with a sore throat using the Centor scoring system and patients meeting three or all four of the criteria were offered a throat swab test for Streptococcus pyogenes, Lancefield group A streptococci. Patients with a positive throat swab test were offered antibiotic treatment.

RESULTS

Following screening by pharmacy staff, 149/367 (40.6%) patients were eligible for throat swab testing. Of these, only 36/149 (24.2%) were positive for group A streptococci. Antibiotics were supplied to 9.8% (n = 36/367) of all patients accessing the service. Just under half of patients that were not showing signs of a bacterial infection (60/123, 48.8%) would have gone to their general practitioner if the service had not been available.

CONCLUSIONS

This study has shown that it is feasible to deliver a community-pharmacy-based screening and treatment service using point-of-care testing. This type of service has the potential to support the antimicrobial resistance agenda by reducing unnecessary antibiotic use and inappropriate antibiotic consumption.

A risk prediction model for severe intraventricular hemorrhage in very low birth weight infants and the effect of prophylactic indomethacin

OBJECTIVE

Develop a risk prediction model for severe intraventricular hemorrhage (IVH) in very low birth weight infants (VLBWI).

STUDY DESIGN

Prospectively collected data of infants with birth weight 500 to 1249 g born between 2001 and 2010 in centers from the Neocosur Network were used. Forward stepwise logistic regression model was employed. The model was tested in the 2011 cohort and then applied to the population of VLBWI that received prophylactic indomethacin to analyze its effect in the risk of severe IVH.

RESULT

Data from 6538 VLBWI were analyzed. The area under ROC curve for the model was 0.79 and 0.76 when tested in the 2011 cohort. The prophylactic indomethacin group had lower incidence of severe IVH, especially in the highest-risk groups.

CONCLUSION

A model for early severe IVH prediction was developed and tested in our population. Prophylactic indomethacin was associated with a lower risk-adjusted incidence of severe IVH.

The Role of Coulombic Forces in Quasi-Two Dimensional Electrochemical Deposition

Recent work demonstrates the relevant influence of convection during growth pattern formation in thin-layer electrochemical deposition. Convection is driven mainly by coulombic forces due to local charges at the tip of the aggregation and by buoyancy forces due to concentration gradients. Here we study through physical experiments and numerical modeling the regime under which coulombic forces are important. In the experimental measurements fluid motion near the growing tips of the deposit is visualized with neutrally buoyant latex spheres and its speed measured with videomicroscope tracking techniques and image processing software. The numerical modeling consists in the solution of the 2D dimensionless Nernst-Planck equations for ion concentrations, the Poisson equation for the electric field and the Navier-Stokes equations for the fluid flow, and a stochastic growth rule for ion deposition. A new set of dimensionless numbers governing electroconvection dominated flows is introduced. Preliminary experimental measurements and numerical results indicate that in the electroconvection dominated regime coulombic forces increase with the applied voltage, and their influence over growth pattern formation can be assessed with the magnitude of the dimensionless electric Froude number. It is suggested that when this number decreases the deposit morphology changes from fractal to dense branching.

Phytoestrogens possess a weak antioxidant activity on low density lipoprotein in contrast to the flavonoid quercetinin vitroin postmenopausal women

BACKGROUND

Phytoestrogens are a family of plant-derived compounds with weak estrogenic and antiestrogenic properties. The antioxidant capacity of phytoestrogens has been proposed as one of the important mechanisms that explain their health benefits.

OBJECTIVE

To determine the in vitro potency of three phytoestrogens, ubiquitous in food, (biochanin A, daidzein and genistein) as antioxidants of low density lipoprotein (LDL) and to compare them with the well-established antioxidant actions of estradiol and quercetin, an ubiquitous flavonoid which is found in high concentration in onions, tea and berries.

METHODS

LDL was isolated by ultracentrifugation from the plasma of ten healthy postmenopausal women who were not on hormone therapy. Aliquots containing 0.5 mg of protein were incubated for 4 h with CuSO4 15 micromol/l to induce oxidative stress and with one of the five compounds studied: estradiol, quercetin, biochanin A, daidzein, and genistein, in doses of 0, 5, 15, 50, 500, 1000 and 2000 micromol/l. In addition, we studied the combined effect of estradiol 1 micromol/l plus quercetin 1 micromol/l, comparing their antioxidant action with that of each compound separately. Malonaldehyde (MDE nmol/ mg protein) was measured as a marker of LDL oxidation.

RESULTS

Estradiol and quercetin induced a dose-dependent decrease in MDE concentration (p < 0.01). Comparing the areas under the curve, the antioxidant effect of quercetin was 8 times higher than the one observed with estradiol (p < 0.01). A 50% decrease in MDE was reached by quercetin at a concentration of 3.4 micromol/l, estradiol at 29 micromol/l, genistein at 280 micromol/l, biochanin at 1312 mmol/l and daidzein at 8007 mmol/l. Estradiol 1 micromol/l and quercetin 1 micromol/l did not modify MDE generation separately, but, when incubated combined, there was a significant decrease of MDE (p < 0.02).

CONCLUSION

The phytoestrogens studied showed a weak antioxidant activity in vitro. The flavonoid quercetin, in contrast, showed the most potent antioxidant activity in vitro, higher than estradiol. Estradiol and quercetin showed additive antioxidant activity. We speculate that different compounds with variable antioxidant effects could amplify their antioxidant capacity when acting combined.

Simulations of transport regime in electrodeposition in different viscosity scenarios

In this work we study the effects of viscosity variations in thin-layer electrochemical deposition (ECD) under galvanostatic conditions through experimental measurements and theoretical modeling. The theoretical model, written in terms of dimensionless quantities, describes diffusive, migratory and convective ion transport in a fluid under galvanostatic conditions. Experiments reveal that as viscosity increases, convection decreases when the cell resistance remains constant. Our numerical model predicts that as viscosity increases, electroconvection becomes less relevant and concentration and convective fronts slow down. The time scaling of this phenomenon is studied and compared to previously reported low viscosity solution studies.

Evaluation of AZD8931, an Equipotent Inhibitor of erbB1, erbB2, and erbB3 Receptor Signaling, on Ligand Stimulated Breast Cancer Cell Lines with Differing Levels of erbB2 Expression

Background: Further treatment options for patients whose breast cancers do not overexpress erbB2 are required. AZD8931, an equipotent, reversible inhibitor of erbB1 (HER1, EGFR), erbB2 (HER2), and erbB3 (HER3) receptor signaling may be useful in this setting and may lead to inhibition of tumor cell proliferation, invasion, metastasis, angiogenesis and tumor cell survival.Objectives: To compare the activity of AZD8931 with other erbB inhibitors (gefitinib [G] and lapatinib [L]) in breast cancer cell lines stimulated with erbB ligands.Methods: A panel of 9 breast cancer cell lines with differing erbB2 expression levels were used: erbB2+/ER+ (BT474c; MDA-MB-361); erbB2+/ER- (MDA-MB-453; SKBR-3); erbB2-/ER+ (MCF7; T47D; ZR75-1); or erbB2-/ER- (MDA-MB-231; MDA-MB-468). Following overnight serum starvation, cells were incubated with AZD8931, G or L (0-10 µM) for 90 min and then stimulated with erbB ligands (50 ng/ml; EGF, TGFα, amphiregulin, epiregulin, betacellulin, neuregulin1, or HBEGF) for 5 min before lysis. Levels of phosphorylated erbB1, erbB2, and erbB3 were analyzed by ELISA. For IC50 determination, mean basal phosphorylation was subtracted. Geometric mean IC50s were calculated from triplicate assays and 2-sided unequal variance t-tests compared logIC50s.Results: AZD8931 demonstrated potent inhibitory activity (IC50s ≤10610 nM) when phosphorylation of erbB1, erbB2 or erbB3 receptors was driven by any erbB ligand. G demonstrated potent inhibitory activity (IC50s ≤20 nM) when the phosphorylation of erbB1 and erbB2 was driven by any erbB ligand. L more strongly inhibited the phosphorylation of erbB2 (IC50s ≤10 nM) than erbB1 (IC50s &lt;400 nM) and showed a ligand and cell-dependant range of activities against erbB3 phosphorylation. AZD8931 was particularly differentiated from G and L in the inhibition of neuregulin1-driven erbB3 phosphorylation: IC50s were lower for AZD8931 (1-5 nM) than for G (1-120 nM) or L (20-80 nM) in the majority of the cell lines tested. Inhibition of erbB1 phosphorylation driven by EGF (IC50s ≤ vs &gt;20 nM), TGFα (≤5 vs &gt;20 nM), HB-EGF (≤ vs &gt;25 nM), or betacellulin (≤6 vs 10-118 nM) also indicated more potent inhibitory activity for AZD8931 over L in cell lines that respond to ligand stimulation. No phosphorylation response to amphiregulin was seen in any of the cell lines.Conclusion: This study demonstrates that in a range of breast cell lines with varying levels of erbB2 expression, AZD8931 is a potent and balanced inhibitor of erbB1, erbB2, and erbB3 signaling. The pharmacological profile of AZD8931 is thus distinct from G and L and suggests that AZD8931 offers an agent to test the hypothesis that combined, balanced inhibition of erbB signaling could provide clinical benefit. AZD8931 may be particularly useful in the treatment of solid tumors that do not overexpress erbB2 including trastuzumab-ineligible breast cancer, an area of unmet medical need. AZD8931 is being evaluated in a Phase I clinical trial.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5059.

Characterization of AZD8931, a potent reversible small molecule inhibitor against epidermal growth factor receptor (EGFR), erythroblastic leukemia viral oncogene homolog 2 (HER2) and 3 (HER3) with a unique and balanced pharmacological profile

11072

Background: Successful combined pharmacological inhibition of EGFR, HER2, and HER3 signaling is currently under investigation in the clinic. HERs (erbB receptors including EGFR, erbB2, erbB3, erbB4) undergo various types of alteration and in many cancers HER ligands are produced either by the tumor cells themselves or surrounding stromal cells. These mechanisms of receptor activation all lead to constitutive proliferative and/or survival signaling driven by homo- and/or heterodimerization of the HER family. Characterization of a novel tyrosine kinase inhibitor with a potent and balanced profile against EGFR, HER2 (erbB2), and HER3 (erbB3) has been carried out. Methods: A range of assays has been developed to assess the detailed pharmacology of AZD8931 and understand how the profile of AZD8931 compares with other HER family inhibitors, such as gefitinib and lapatinib. These assays have provided unique insights into the pharmacology of these drugs that result from the varying levels of HER and their associated ligands. Results: Across a number of cell systems, AZD8931 has been shown to be a potent inhibitor of tumor cell growth. This effect is through the ability of AZD8931 to inhibit potently the phosphorylation of EGFR (0.004 μM; 95% CIR: 1.377), HER2 (0.003 μM; 95% CIR: 1.817) and HER3 (0.004 μM; 95% CIR: 1.890) in a balanced manner. Furthermore, when compared to control AZD8931 has significant and dramatic effects on the downstream signaling pathways (pAKT [p=0.002] & pMAK [NS]), apoptotic (M30 [p=0.004]), and proliferative (Ki67 [p<0.0005]) endpoints. The novel agent AZD8931 displays a distinct pharmacological profile compared to both gefitinib and lapatinib. Conclusions: Based on our data as well as published literature, the combined pharmacological inhibition of EGFR, HER2, and HER3 signaling has not yet been tested in the clinic. AZD8931 offers an agent to test the hypothesis that combined inhibition of HER signaling could provide additional clinical benefit in cancer, particularly in the majority of solid tumors that do not overexpress HER2.

[Table: see text]

Ion transport in tumors under electrochemical treatment: in vivo, in vitro and in silico modeling

The electrochemical treatment of cancer (EChT) consists in the passage of a direct electric current through two or more electrodes inserted locally in the tumor tissue. The extreme pH changes induced have been proposed as the main tumor destruction mechanism. Here, we study ion transport during EChT through a combined modeling methodology: in vivo modeling with BALB/c mice bearing a subcutaneous tumor, in vitro modeling with agar and collagen gels, and in silico modeling using the one-dimensional Nernst-Planck and Poisson equations for ion transport in a four-ion electrolyte. This combined modeling approach reveals that, under EChT modeling, an initial condition with almost neutral pH evolves between electrodes into extreme cathodic alkaline and anodic acidic fronts moving towards each other, leaving the possible existence of a biological pH region between them; towards the periphery, the pH decays to its neutral values. pH front tracking unveils a time scaling close to t(1/2), signature of a diffusion-controlled process. These results could have significant implications in EChT optimal operative conditions and dose planning, in particular, in the way in which the evolving EChT pH region covers the active cancer cells spherical casket.

Slit beam shaping method for femtosecond laser direct-write fabrication of symmetric waveguides in bulk glasses

We report both theoretical and experimental results of a slit beam shaping configuration for fabricating photonic waveguides by use of femtosecond laser pulses. Most importantly we show the method supports focusing objectives with a long depth of field and allows the direct-writing of microstructures with circular cross-sections whilst employing a perpendicular writing scheme. We applied this technique to write low loss (0.39 dB/cm), single mode waveguides in phosphate glass.

Three-dimensional nature of ion transport in thin-layer electrodeposition

A generalized three-dimensional model for ion transport in electrodeposition is introduced. Ion transport is mainly governed by diffusion, migration, and convection. When convection prevails, in particular, in the limiting case of gravity-driven convection, the model predicts concentration shells and convection rolls and their interaction mode with a deposit tip: shell and roll bend and surround the tip forming a three-dimensional envelope tube squeezed at the deposit tip. In the limiting case of electrically driven convection, a vortex ring and an electric spherical drop crowning the deposit tip are predicted. When gravity and electric convection are both relevant, the interaction of ramified deposits, vortex tubes and rings, and electric spherical drops, leading to complex helicoidal flow, is predicted. Many of these predictions are experimentally observed, suggesting that ion transport underlying dendrite growth is remarkably well captured by our model.

Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice

Temperatures were recorded at several body sites in emperor penguins (Aptenodytes forsteri) diving at an isolated dive hole in order to document temperature profiles during diving and to evaluate the role of hypothermia in this well-studied model of penguin diving physiology. Grand mean temperatures (+/-S.E.) in central body sites during dives were: stomach: 37.1+/-0.2 degrees C (n=101 dives in five birds), pectoral muscle: 37.8+/-0.1 degrees C (n=71 dives in three birds) and axillary/brachial veins: 37.9+/-0.1 degrees C (n=97 dives in three birds). Mean diving temperature and duration correlated negatively at only one site in one bird (femoral vein, r=-0.59, P<0.05; range <1 degrees C). In contrast, grand mean temperatures in the wing vein, foot vein and lumbar subcutaneous tissue during dives were 7.6+/-0.7 degrees C (n=157 dives in three birds), 20.2+/-1.2 degrees C (n=69 in three birds) and 35.2+/-0.2 degrees C (n=261 in six birds), respectively. Mean limb temperature during dives negatively correlated with diving duration in all six birds (r=-0.29 to -0.60, P<0.05). In two of six birds, mean diving subcutaneous temperature negatively correlated with diving duration (r=-0.49 and -0.78, P<0.05). Sub-feather temperatures decreased from 31 to 35 degrees C during rest periods to a grand mean of 15.0+/-0.7 degrees C during 68 dives of three birds; mean diving temperature and duration correlated negatively in one bird (r=-0.42, P<0.05). In general, pectoral, deep venous and even stomach temperatures during diving reflected previously measured vena caval temperatures of 37-39 degrees C more closely than the anterior abdominal temperatures (19-30 degrees C) recently recorded in diving emperors. Although prey ingestion can result in cooling in the stomach, these findings and the lack of negative correlations between internal temperatures and diving duration do not support a role for hypothermia-induced metabolic suppression of the abdominal organs as a mechanism of extension of aerobic dive time in emperor penguins diving at the isolated dive hole. Such high temperatures within the body and the observed decreases in limb, anterior abdomen, subcutaneous and sub-feather temperatures are consistent with preservation of core temperature and cooling of an outer body shell secondary to peripheral vasoconstriction, decreased insulation of the feather layer, and conductive/convective heat loss to the water environment during the diving of these emperor penguins.

Mediterranean diet, but not red wine, is associated with beneficial changes in primary haemostasis

OBJECTIVE

(1) To compare the effect of an alcohol-free Mediterranean-type diet (MD) and a high-fat diet (HFD) on variables of primary haemostasis (bleeding time, plasma von Willebrand factor and platelet aggregation/secretion). (2) To test whether red wine supplementation modified these variables, independently of the diet.

DESIGN, SUBJECTS AND INTERVENTION

Controlled prospective intervention study. Two groups, each consisting of 21 healthy male university students (22+/-3.4 y), received either MD or HFD during 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline (T0) and T30, T60 and T90-day samples were drawn. Bleeding time was measured before (day 30) and after (day 60) wine supplementation. No drop out from the study was experienced.

SETTING

University campus and outpatient nutrition clinic.

RESULTS

All baseline (day 0) variables did not differ significantly between study groups. On day 30, individuals on MD had significantly higher levels of plasma beta-carotene, folate, ascorbate, and eicosapentaenoic acid in plasma lipid fractions, than those on HFD. Total plasma cholesterol, HDL and LDL did not change significantly in either study group at any time point. After 30 days on each diet, individuals on MD had longer bleeding time (BT) than those on HFD (7.6+/-2.8 vs 5.8+/-1.7 min; P=0.017). BT did not change significantly after I month of wine supplementation (7.1+/-2.0 vs 5.5+/-2.0 min, respectively). Plasma von Willebrand factor (vWF : Ag) on day 0 was 89+/-40 and 111+/-70% in MD and HFD groups, respectively (P=0.21). These values did not change significantly at 30, 60 or 90 days. MD intake was associated with an increase in platelet serotonin secretion (P=0.02) and a marginal increase in platelet aggregation after stimulation with epinephrine (P=0.07). Wine intake resulted in a marginal decrease in platelet (14)C-5-HT secretion with 4 micro M ADP (P=0.07). However, both platelet aggregation and secretion were consistently increased when using collagen as agonist (1 and 2 micro g/ml, P=0.01).

CONCLUSION

The longer BT in individuals on MD, obtained independently of red wine, denotes less interaction of platelets with the vascular wall, which could be beneficial from the point of view of cardiovascular (CV) risk. This effect is not explained by changes in the measured haemostatic determinants of BT (plasma vWF, ex vivo platelet function), and might be attributed to other as yet unknown vascular factors. Moderate consumption of red wine results in a significant increase in ex vivo platelet aggregation and secretion after stimulation with collagen. This observation contradicts previous reports, although further studies are required to elucidate the influence of this finding on CV risk.

Stroke frequencies of emperor penguins diving under sea ice

During diving, intermittent swim stroke patterns, ranging from burst/coast locomotion to prolonged gliding, represent potential energy conservation mechanisms that could extend the duration of aerobic metabolism and, hence,increase the aerobic dive limit (ADL, dive duration associated with onset of lactate accumulation). A 5.6 min ADL for emperor penguins had been previously determined with lactate measurements after dives of &lt;50 m depth. In order to assess locomotory patterns during such dives, longitudinal acceleration was measured with an attached accelerometer in 44 dives of seven adult birds diving from an isolated dive hole in the sea ice of McMurdo Sound, Antarctica. Detection of wing strokes in processed accelerometer data was verified in selected birds with analysis of simultaneous Crittercam underwater video footage. Mean dive duration of birds equipped with the accelerometer and a time-depth recorder (TDR) was 5.7±2.2 min; 48% of these dives were greater than the measured 5.6 min ADL (ADLM). Highest stroke frequencies (0.92±0.31 Hz, N=981) occurred during the initial descent to 12 m depth. Swimming effort was reduced to a mean stroke frequency&lt;0.70 Hz during other phases of the dive (while traveling below 12 m depth,during foraging ascents/descents to and from the sub-ice surface, and during final ascents to exit). The longest stroke interval (8.6 s) occurred during a feeding excursion to the undersurface of the ice. In dives&gt;ADLM, mean stroke frequency during travel segments was significantly less than that in dives &lt;ADLM(P&lt;0.05). Mean stroke frequency of the entire dive correlated inversely (P&lt;0.05) with diving duration (r=-0.67) and with mean dive depth (r=-0.43). Emperor penguins did not exhibit any significant (&gt;10 s) periods of prolonged gliding during these shallow(&lt;60 m) foraging dives. However, a stroke/glide pattern was evident with more than 50% of strokes associated with a stroke interval &gt;1.6 s, and with lower stroke frequency associated with increased dive duration.

Transition from gravito- to electroconvective regimes in thin-layer electrodeposition

The transition from gravitoconvective to electroconvective prevailing regimes in thin-layer electrochemical deposition is analyzed through variations of electrolyte viscosity at constant cell thickness. The distribution of velocity directions at the deposit front is a measure of the relative weight of electroconvection versus gravitoconvection, and a signature of that transition. The experiments are carried out under galvanostatic conditions in convection prevailing regimes. Particle image velocimetry reveals that at low viscosities, buoyancy driven convection dominates; as viscosity increases, electrically driven convection becomes more important, eventually prevailing. The transition is observed at 1.5 times the viscosity of water. The theoretical model presented reveals that an increase of the Poisson and Reynolds numbers and a decrease of the Peclet and electric Grashof numbers, when viscosity increases, makes the electroconvective motion relatively more important. The model predicts a transition at approximately two times the viscosity of water. We may conclude that, in a physicochemical hydrodynamic flow involving ions, under galvanostatic conditions, increasing viscosity damps gravitoconvection and enhances electroconvection.

Pharmacokinetics and inflammatory fluid penetration of intravenous daptomycin in volunteers

The lipopeptide antimicrobial daptomycin was administered intravenously at a dose of 4 mg/kg of body weight to seven healthy male volunteers. The concentrations of daptomycin in plasma, cantharidin-induced inflammatory fluid, and urine were measured by a microbiological assay. The mean +/- standard deviation peak concentrations in plasma and inflammatory fluid were 77.5 +/- 8.3 and 27.6 +/- 9.5 microg/ml, respectively; the mean terminal elimination half-lives were 7.74 and 13.2 h, respectively. The overall penetration of total drug into the inflammatory fluid (measured by ratio of the area under the concentration-time curve from 0 to 24 h for inflammatory fluid compared with that for plasma) was 68.4%. The mean urinary recovery over 24 h was 59.7%.

Single-dose pharmacokinetics and penetration of BMS 284756 into an inflammatory exudate

The pharmacokinetics of a single dose of BMS 284756 were determined following oral administration of a 600-mg dose to eight healthy male volunteers. Concentrations of the drug were measured in plasma and a cantharidine-induced inflammatory exudate by a microbiological assay. The mean peak concentration in plasma of 10.4 microg/ml (standard deviation [SD], 1.3 microg/ml) was attained at a mean time of 1.2 h (SD, 0.5 h) after the dose. The penetration into the inflammatory exudate was 82% (SD, 15.7%). A mean peak concentration of 7.2 microg/ml (SD, 2.4 microg/ml) was attained in the inflammatory exudate at 5.3 h (SD, 1.5 h). The elimination half-lives from plasma and inflammatory fluid were 9.8 h (SD, 1.1 h) and 8.5 h (SD, 1.9 h), respectively. The areas under the concentration-time curves for plasma and inflammatory fluid were 96.7 microg x h/ml (SD, 10.3 microg x h/ml) and 77.9 microg x h/ml (SD, 19.2 microg x h/ml), respectively.