Discovery and quantification of a widespread methane ebullition event in a coastal inlet (Baltic Sea) using a novel sonar strategy

How much of the greenhouse gas methane is transported from the seafloor to the atmosphere is unclear. Here, we present data describing an extensive ebullition event that occurred in Eckernförde Bay, a shallow gas-hosting coastal inlet in the Baltic Sea, in the fall of 2014. A weak storm induced hydrostatic pressure fluctuations that in turn stimulated gas ebullition from the seabed. In a finely tuned sonar survey of the bay, we obtained a hydroacoustic dataset with exceptionally high sensitivity for bubble detection. This allowed us to identify 2849 bubble seeps rising within 28 h from the seafloor across the 90 km² study site. Based on our calculations, the estimated bubble-driven episodic methane flux from the seafloor across the bay is 1,900 μMol m⁻² d⁻¹. Our study demonstrates that storm-associated fluctuations of hydrostatic pressure induce bulk gas-driven ebullitions. Given the extensive occurrence of shallow gas-hosting sediments in coastal seas, similar ebullition events probably take place in many parts of the Western Baltic Sea. However, these are likely to be missed during field investigations, due to the lack of high-quality data acquisition during storms, such that atmospheric inputs of marine-derived methane will be highly underestimated.

Pharmacokinetics and Pharmacodynamics of Melagatran, a Novel Synthetic LMW Thrombin Inhibitor, in Patients with Acute DVT

Forty-eight patients with acute proximal deep vein thrombosis (DVT) were randomised to intravenous infusions for 4 to 6 days with melagatran, a novel synthetic low molecular weight thrombin inhibitor, or unfractionated heparin adjusted by the activated partial thromboplastin time (APTT). The aim of the study was to investigate the pharmacokinetics, pharmacodynamics and the safety of melagatran therapy at three different doses. Steady-state plasma concentrations were rapidly achieved and maintained throughout the infusion period. The mean plasma concentrations in the low, medium and high dose groups were 0.17, 0.31 and 0.53 μmol/l, respectively. The prolongation of APTT was stable during the melagatran infusions and correlated to the plasma concentration. Phlebographically verified regression of thrombus size measured as decrease in Marder score was seen after 4 to 6 days in 8 of 12 patients, 6 of 12 patients and 5 of 11 patients in the low, medium and high dose groups of melagatran and in 5 of the heparin-treated patients. In the low dose group with melagatran, thrombus extension was seen in one patient. At the dose levels studied, melagatran was well tolerated with no clinically significant bleeding problems, suggesting that melagatran could safely be given to patients suffering from DVT.

Value of high-resolution MR in patients scheduled for cochlear implantation

Objective: To determine sensitivity and specificity of high-resolution MR imaging and of high-resolution axial CT (HRCT) and to compare the two modalities in predicting the surgical and functional success of cochlear implantation.

Material and Methods: The presurgical MR images (2D T2W TSE, 3D T2*W CISS, plain and contrast-enhanced 3D T1W MP-RAGE) and axial HRCT findings of 26 patients were evaluated with regard to the predictive value concerning the success of cochlear implantation.

Results: We found a high correlation between MR and HRCT and the success of cochlear implantation. In all 26 patients, the MR-based predictions concerning the success of cochlear implantation were correct. In 10 patients, MR gave additional information to HRCT. In all patients, MR gave sufficient information about the status of the inner ear, inner auditory canal and cochlear nerve to aid the surgeon during the operation.

Conclusion: A high-resolution MR protocol consisting of coronal 2D T2W TSE, 3D T2*W axial CISS, plain and contrast-enhanced sagittal T1W 3D MP-RAGE is recommended for the evaluation of candidates scheduled for cochlear implantation. It provides information which cannot be obtained by HRCT.

Crystal structure analysis and extremely long-living light-induced metastable states in RbY[Fe(CN)5NO]2·10H2O and CsY[Fe(CN)5NO]2·10H2O

Crystal structures of both isostructural com-pounds were solved from single crystal X-ray diffraction data (space group P21/n; Z = 4; Rb-compound: a = 9.812(1) Å, b = 25.793(3) Å, c = 11.777(2) Å, β = 104.68(1)°, R gt(F) = 0.0458, wR ref(F 2) = 0.0918; Cs-compound: a = 9.9058(8) Å, b = 25.919(2) Å, c = 11.883(1) Å,β = 105.542(7)o, Rgt(F) = 0.0450,wRref(F2) = 0.0951. The main structural feature is the nitrosylpentacyanoferrate(II)-complex [Fe(CN)5NO]2–. The iron atoms are coordinated to five cyanide and one nitrosyl ligand. The coordination polyhedron of the Y3+ cation is a distorted tetragonal antiprism built up from three nitrogen atoms of three complexes and five water molecules. Both rubidium and cesium ions are surrounded by seven cyanide groups of five complexes and one water molecule to form a distorted bicapped trigonal prism. One metastable state (SI) can be excited by irradiation with light in the spectral range of 400–500 nm at temperatures below 180 K. The radiationless thermal decay is detected by Differential Scanning Calorimetry by heating above T = 180 K. Evaluating the exothermal heat flow using the Arrhenius law yields an activation energy of EA = 0.64(2) eV and a frequency factor of Z = 20(8)·1012s–1 for the rubidium compound and EA = 0.56(2) eV, Z = 30(8)·1010s–1 for the cesium compound. The contribution of the cations on the decay temperature of the metastable states is discussed on the basis of the atomic distances and coordinations.

Effects of digoxin on electrocardiogram in patients with acute atrial fibrillation--a randomized, placebo-controlled study. Digitalis in Acute Atrial Fibrillation (DAAF) Trial Group

BACKGROUND

Studies of healthy volunteers or patients in sinus rhythm have indicated that treatment with digoxin produces characteristic changes in the electrocardiogram (ECG). No randomized, placebo-controlled studies are available and no study has investigated the effect on ECG in patients with atrial fibrillation.

HYPOTHESIS

In a substudy to a trial comparing the therapeutic effect of intravenously administered digoxin with placebo in patients with acute atrial fibrillation, we investigated these effects as well as the relation between ECG changes and serum concentration of digoxin.

METHODS

In all, 167 patients were included. Standard ECGs recorded at baseline, and at 2, 6, 12, and 16 h after randomization were digitized, and changes in RR-intervals, QRS width, ST-segment amplitude at 60 ms after the J point, T-wave amplitude, and QTc interval were calculated. Furthermore, the correlation between the serum concentration of digoxin at 16 h after inclusion and changes on the ECG was analyzed.

RESULTS

Compared with placebo, digoxin resulted in an increase in RR-interval (p < 0.0001), a decrease in ST-segment and T-wave amplitude (p = 0.009 and p = 0.002, respectively), and in the QTc interval (p = 0.01). These changes were present 2 h after the first dose, but were more pronounced after 16 h. There was no significant correlation between serum concentration of digoxin and ECG changes at 16 h.

CONCLUSION

Compared with placebo, digoxin produces significant changes on ECG in patients with acute atrial fibrillation. The changes are in accordance with previous findings in individuals in sinus rhythm. There was no correlation between serum concentration of digoxin and ECG changes.

Symptoms of depression, prescription of benzodiazepines, and the risk of death in hemodialysis patients in Japan

Many hemodialysis patients in Japan have symptoms of depression, but whether those patients are treated appropriately is unknown. As part of the Dialysis Outcomes and Practice Patterns Study, data on symptoms of depression, physician-diagnosed depression, prescribed medications, and death were collected prospectively in cohorts in Japan (n=1603) and 11 other countries (n=5872). Symptoms of depression were as prevalent in Japan as elsewhere, but in Japan a much smaller percentage of patients had physician-diagnosed depression: only 2% in Japan vs 17% elsewhere. Antidepressants were much less commonly prescribed in Japan: only 1% in Japan vs 17% elsewhere for patients with many and frequent symptoms of depression, and 16% in Japan vs 34% elsewhere for patients with physician-diagnosed depression. In Japan, symptoms of depression were associated with prescription of benzodiazepines (without antidepressants), and patients with physician-diagnosed depression were twice as likely to be given benzodiazepines: 32% in Japan vs 16% elsewhere. Benzodiazepine monotherapy was associated with death (relative risk 1.56, 95% confidence interval (CI), 1.25-1.94), even after adjustments for 13 likely confounders (relative risk 1.27, 95% CI, 1.01-1.59). Hemodialysis patients in Japan with symptoms of depression are given not antidepressants but benzodiazepines, a practice associated with higher mortality.

Degenerative diseases of the lumbar spine. Comparison of the multiecho data image combination sequence with magnetization transfer saturation pulse versus lumbar myelography/postmyelographic computed tomography

PURPOSE

To compare a T2* weighted 2D spoiled gradient echo multiecho sequence (MEDIC) with magnetization transfer saturation pulse versus lumbar myelography and postmyelographic computed tomography (pCT).

MATERIAL AND METHODS

84 disk levels in 27 patients were examined. The vertebral bodies, intervertebral disks, neural foramina, cauda equina, ligamentum flavum, and narrowing of the spinal canal were investigated using an evaluation scale. In addition, the pCT and the MEDIC sequence were evaluated for assessing the narrowing of the neural foramina in a phantom study using a cadaver preparation of the lumbar spine.

RESULTS

A total of 28 disk herniations, 11 cases of osteophytes narrowing the spinal canal or the neural foramina, and 7 spinal canal stenoses were detected. The pCT was significantly better in visualizing the cauda equina. The MEDIC sequence was significantly superior in visualizing the extension of the ligamentum flavum. No statistical differences between either image modality were found concerning assessment of the narrowing of the neural foramina and the spinal canal, nor regarding evaluation of the vertebral disk and the vertebral body. Measurements of the phantom study showed that the MEDIC sequence did not overestimate narrowing of the neural foramina.

CONCLUSIONS

The T2* MEDIC sequence has proved to be as accurate as pCT in evaluating osteophytes and narrowing of the neural foramina. In doubtful standard magnetic resonance imaging findings, this means that an additional axial T2* MEDIC sequence may be of value in reaching the same accuracy as pCT.

Degenerative diseases of the cervical spine: comparison of a multiecho data image combination sequence with a magnetisation transfer saturation pulse and cervical myelography and CT

Assessing degenerative disease in the cervical spine remains a challenge. There is much controversy about imaging the cervical spine using MRI. Our aim in this prospective study was to compare a T2*-weighted 2D spoiled gradient-echo multiecho sequence (MEDIC) with a magnetisation transfer saturation pulse with cervical myelography and postmyelographic CT. Using an assessment scale we looked at the vertebral bodies, intervertebral discs, neural foramina, anterior and posterior nerve roots, grey matter, ligamentaflava, oedema in the spinal cord and stenosis of the spinal canal. We also evaluated postmyelography CT and the MEDIC sequence for assessing narrowing of the neural foramina in a cadaver cervical spine. We examined 67 disc levels in 18 patients, showing 18 disc prolapses and 21 osteophytes narrowing the spinal canal or the neural foramina. All MRI studies showed these abnormalities findings equally well. Postmyelography CT was significantly better for showing the bony structures and the anterior and posterior nerve roots. The MEDIC sequence provided excellent demonstration of soft-tissue structures such as the intervertebral disc and ligamentum flavum. No statistical differences between the imaging modalities were found in the assessment of narrowing of the neural foramina or the extent of spinal stenosis. The cadaver measurements showed no overestimation of abnormalities using the MEDIC sequence.