Energy and angular momentum balance in wall-bounded superfluid turbulence

A superfluid in the absence of the viscous normal component should be the best realization of an ideal inviscid Euler fluid. As expressed by d'Alembert's famous paradox, an ideal fluid does not exert drag on bodies past which it flows, or in other words, it does not exchange momentum with them. Also, the flow of an ideal fluid does not dissipate kinetic energy. We study experimentally whether these properties apply to the flow of superfluid 3He-B in a rotating cylinder at low temperatures. It is found that ideal behavior is broken by quantum turbulence, which leads to substantial energy dissipation, as observed also earlier. Here we show that remarkably, nearly ideal behavior is preserved with respect to the angular-momentum exchange between the superfluid and its container, i.e., the drag almost disappears in the zero-temperature limit. This mismatch between energy and angular-momentum transfer results in a new physical situation where the proper description of wall-bounded quantum turbulence requires two effective friction parameters, one for energy dissipation and another for momentum coupling, which become substantially different at very low temperatures.Comment: 7 pages, 3 figure

The breast feeding mother and xenon anaesthesia: four case reports. Breast feeding and xenon anaesthesia

<p>Abstract</p> <p>Background</p> <p>Four nursing mothers consented to anaesthesia for urgent surgery only on condition that their ability to breast feed would not be impaired.</p> <p>Methods</p> <p>Following induction of general anaesthesia with propofol and remifentanil, 65-69% xenon supplemented with remifentanil was used as an inhalational anaesthetic for maintenance.</p> <p>Results</p> <p>After finishing surgery the women could be extubated between 2:52 and 7:22 minutes. The women were fully alert just minutes after extubation and spent about 45 minutes in the recovery room before discharge to a regular ward. They resumed regular breast feeding some time later. The propofol concentration in the blood was measured after 0, 30, 90, and 300 minutes and in the milk after 90 and 300 minutes. Just 90 minutes after extubation, the concentration of propofol in the milk was limited (> 3 mg/l) so that pharmacological effects on the babies were excluded after oral intake. Also, no traces of xenon gas were found in the maternal milk at any time. After propofol induction and maintenance of anaesthesia with xenon in combination with a water-soluble short-acting drug like remifentanil, the concentration of propofol in maternal milk is low (> 3 mg/l 90 min after anesthesia) and harmless after oral intake.</p> <p>Conclusions</p> <p>These results, as well as the rapid elimination and absence of metabolism of xenon, are of great interest to nursing mothers. General anaesthesia with propofol for induction only, combined with remifentanil and xenon for maintenance, has not yet been described in breast feeding mothers.</p

Purification and functional characterisation of rhiminopeptidase A, a novel aminopeptidase from the venom of Bitis gabonica rhinoceros

This study describes the discovery and characterisation of a novel aminopeptidase A from the venom of B. g. rhinoceros and highlights its potential biological importance. Similar to mammalian aminopeptidases, rhiminopeptidase A might be capable of playing roles in altering the blood pressure and brain function of victims. Furthermore, it could have additional effects on the biological functions of other host proteins by cleaving their N-terminal amino acids. This study points towards the importance of complete analysis of individual components of snake venom in order to develop effective therapies for snake bites

Particle tracking velocimetry and accelerometry (PTVA) measurements applied to quasi-two-dimensional multi-scale flows

Accepted versio

The C-terminal region of Trypanosoma cruzi MASPs is antigenic and secreted via exovesicles.

Trypanosoma cruzi is the etiological agent of Chagas disease, a neglected and emerging tropical disease, endemic to South America and present in non-endemic regions due to human migration. The MASP multigene family is specific to T. cruzi, accounting for 6% of the parasite's genome and plays a key role in immune evasion. A common feature of MASPs is the presence of two conserved regions: an N-terminal region codifying for signal peptide and a C-terminal (C-term) region, which potentially acts as GPI-addition signal peptide. Our aim was the analysis of the presence of an immune response against the MASP C-term region. We found that this region is highly conserved, released via exovesicles (EVs) and has an associated immune response as revealed by epitope affinity mapping, IFA and inhibition of the complement lysis assays. We also demonstrate the presence of a fast IgM response in Balb/c mice infected with T. cruzi. Our results reveal the presence of non-canonical secreted peptides in EVs, which can subsequently be exposed to the immune system with a potential role in evading immune system targets in the parasite

Aneurysm of antecubital vein: an unusual complication of peripheral intravenous cannulation

<p>Abstract</p> <p>Background</p> <p>Intravenous cannulation is a very common procedure. Venous aneurysm secondary to peripheral intravenous cannulation is extremely rare. Moreover, venous aneurysm can mimic other conditions and may confuse the issue.</p> <p>Case presentation</p> <p>We describe a case of a 45-year-old woman who was referred with the diagnosis of varicose vein of right arm. A history of intravenous cannulation at the same site was noted that raised suspicion. The swelling was compressible and turned out to be a venous aneurysm. The lesion was completely excised. Postoperative recovery was uneventful. Histology findings were in conformity with the preoperative diagnosis.</p> <p>Conclusion</p> <p>Caution should be exercised in diagnosing varicose vein at a site that bears a history of intravenous cannulation. The case also raises an important issue regarding consent. Should patients undergoing peripheral intravenous cannulation be warned of this rare complication?</p

Towards a Realistic F-theory GUT

We consider semi-local F-theory GUTs arising from a single E_8 point of local enhancement, leading to simple GUT groups based on E_6, SO(10) and SU(5) with SU(3), SU(4) and SU(5) spectral covers, respectively. Assuming the minimal Z_2 monodromy, we determine the homology classes and the associated spectra after flux breaking for each case. Our analysis includes the GUT singlets which have hitherto been ignored but which play a crucial role in phenomenology. Using these results we construct an E_6 based model that demonstrates, for the first time, that it is possible to construct a phenomenologically viable model which leads to the MSSM at low energies. The exotics that result from flux breaking all get a large mass when singlet fields acquire vacuum expectation values driven by D- and F-flatness. Due to the underlying GUT symmetry and the U(1)s descending from E_8, bare baryon- and lepton-number violating terms are forbidden up to and including dimension 5. As a result nucleon decay is naturally suppressed below present bounds. The mu-term is forbidden by the U(1) but is generated at the SUSY breaking scale when a further singlet field acquires a TeV scale vacuum expectation value, driven by the spontaneous breaking of the electroweak symmetry. After including the effect of flux and instanton corrections acceptable quark and charged lepton masses and mixing angles can be obtained. Neutrinos get a mass from the see-saw mechanism through their coupling to singlet neutrinos that acquire large Majorana mass as a result of the monodromy.Comment: This version incorporates an improved discussion of the suppression of nucleon decay and the non-perturbative breaking of the U(1) symmetrie

Evaluation of a new Rapid Antimicrobial Susceptibility system for Gram-negative and Gram-positive bloodstream infections: speed and accuracy of Alfred 60AST.

BACKGROUND: Blood stream infections (BSIs) are a major cause of morbidity and mortality. The time from taking blood cultures to obtain results of antibiotic sensitivity can be up to five days which impacts patient care. The Alfred 60 AST™ can reduce laboratory time from positive culture bottle to susceptibility results from 16 to 25 h to 5-6 h, transforming patient care. To evaluate the diagnostic accuracy of a rapid antimicrobial susceptibility system, the Alfred 60 AST™, in clinical isolates from patients with BSIs and confirm time to results. 301 Gram-negative and 86 Gram-positive isolates were analysed directly from positive blood culture bottles following Gram staining. Antimicrobial susceptibility results and time-to-results obtained by rapid Alfred 60 AST system and BD Phoenix were compared . RESULTS: A total of 2196 antimicrobial susceptibility test results (AST) were performed: 1863 Gram-negative and 333 Gram-positive. AST categorical agreement (CA) for Alfred 60 AST™ was 95% (1772/1863) for Gram-negative and 89% (295/333) for Gram-positive isolates. Gram-negative CA: ampicillin 96% (290/301); ciprofloxacin 95% (283/297); ceftriaxone 96% (75/78); meropenem 97% (288/297); piperacillin-tazobactam 95% (280/295); gentamicin 94% (279/297) and amikacin 93% (277/298). The median time to susceptibility results from blood culture flagging positive was 6.3 h vs 20 h (p < 0.01) for Alfred system vs BD Phoenix™. CONCLUSION: Alfred 60 AST system greatly reduced time to antimicrobial susceptibility results in Gram-negative and Gram-positive BSIs with good performance and cost, particularly for Gram-negative bacteraemia

Curettage of benign bone tumors without grafts gives sufficient bone strength: A case-series of 78 patients

Background and purpose The defect that results after curettage of a bone tumor is usually filled in the same way. We report the outcome in patients with benign bone tumors that were treated with curettage but no filling