Compartmentalized Intracellular Click Chemistry with Biodegradable Polymersomes.

Polymersome nanoreactors that can be employed as artificial organelles have gained much interest over the past decades. Such systems often include biological catalysts (i.e., enzymes) so that they can undertake chemical reactions in cellulo. Examples of nanoreactor artificial organelles that acquire metal catalysts in their structure are limited, and their application in living cells remains fairly restricted. In part, this shortfall is due to difficulties associated with constructing systems that maintain their stability in vitro, let alone the toxicity they impose on cells. This study demonstrates a biodegradable and biocompatible polymersome nanoreactor platform, which can be applied as an artificial organelle in living cells. The ability of the artificial organelles to covalently and non-covalently incorporate tris(triazolylmethyl)amine-Cu(I) complexes in their membrane is shown. Such artificial organelles are capable of effectively catalyzing a copper-catalyzed azide-alkyne cycloaddition intracellularly, without compromising the cells' integrity. The platform represents a step forward in the application of polymersome-based nanoreactors as artificial organelles.

Sodium chloride inhibits effective bubbly drag reduction in turbulent bubbly Taylor-Couette flows.

Using the Taylor-Couette geometry we experimentally investigate the effect of salt on drag reduction caused by bubbles present in the flow. We combine torque measurements with optical high-speed imaging to relate the bubble size to the drag experienced by the flow. Previous studies have shown that a small percentage of air (4%) can lead to dramatic drag reduction (40%). In contrast to previous laboratory experiments, which mainly used fresh water, we will vary the salinity from that of fresh water to the average salinity of ocean water. We find that the drag reduction is increasingly more inhibited for increasing salt concentrations, going from 40% for fresh water to just 15% for sea water. Salts present in the working fluid inhibit coalescence events, resulting in smaller bubbles in the flow and, with that, a decrease in the drag reduction. Above a critical salinity, increasing the salinity has no further effect on the size of bubbles in the flow and thus the drag experienced by the flow. Our new findings demonstrate the importance of sodium chloride on the bubbly drag reduction mechanism, and will further challenge naval architects to implement promising air lubrication systems on marine vessels. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

Recent developments of turbulent emulsions in Taylor-Couette flow.

Emulsions are common in many natural and industrial settings. Recently, much attention has been paid to understanding the dynamics of turbulent emulsions. This paper reviews some recent studies of emulsions in turbulent Taylor-Couette flow, mainly focusing on the statistics of the dispersed phase and the global momentum transport of the system. We first study the size distribution and the breakup mechanism of the dispersed droplets for turbulent emulsions with a low volume-fraction (dilute) of the dispersed phase. For systems with a high volume-fraction (dense) of the dispersed phase, we address the detailed response of the global transport (effective viscosity) of the turbulent emulsion and its connection to the droplet statistics. Finally, we will discuss catastrophic phase inversions, which can happen when the volume-fraction of the dispersed phase exceeds a critical value during dynamic emulsification. We end the manuscript with a summary and an outlook including some open questions for future research. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

Small Charging Energies and g-Factor Anisotropy in PbTe Quantum Dots.

PbTe is a semiconductor with promising properties for topological quantum computing applications. Here, we characterize electron quantum dots in PbTe nanowires selectively grown on InP. Charge stability diagrams at zero magnetic field reveal large even-odd spacing between Coulomb blockade peaks, charging energies below 140 µeV and Kondo peaks in odd Coulomb diamonds. We attribute the large even-odd spacing to the large dielectric constant and small effective electron mass of PbTe. By studying the Zeeman-induced level and Kondo splitting in finite magnetic fields, we extract the electron g-factor as a function of magnetic field direction. We find the g-factor tensor to be highly anisotropic with principal g-factors ranging from 0.9 to 22.4 and to depend on the electronic configuration of the devices. These results indicate strong Rashba spin-orbit interaction in our PbTe quantum dots.

Catastrophic Phase Inversion in High-Reynolds-Number Turbulent Taylor-Couette Flow.

Emulsions are omnipresent in the food industry, health care, and chemical synthesis. In this Letter the dynamics of metastable oil-water emulsions in highly turbulent (10^{11}≤Ta≤3×10^{13}) Taylor-Couette flow, far from equilibrium, is investigated. By varying the oil-in-water void fraction, catastrophic phase inversion between oil-in-water and water-in-oil emulsions can be triggered, changing the morphology, including droplet sizes, and rheological properties of the mixture, dramatically. The manifestation of these different states is exemplified by combining global torque measurements and local in situ laser induced fluorescence microscopy imaging. Despite the turbulent state of the flow and the dynamic equilibrium of the oil-water mixture, the global torque response of the system is found to be as if the fluid were Newtonian, and the effective viscosity of the mixture was found to be several times bigger or smaller than either of its constituents.

Pharmacokinetics of fosfomycin in patients with prophylactic treatment for recurrent Escherichia coli urinary tract infection.

OBJECTIVES: To evaluate the pharmacokinetics and clinical effectiveness of IV and oral fosfomycin treatment in patients with recurrent urinary tract infection (rUTI) with Escherichia coli. PATIENTS AND METHODS: Patients with rUTI treated with 3 g of oral fosfomycin every 72 h for at least 14 days were included in a prospective open-label single-centre study. Serum samples were taken after oral and IV administration of fosfomycin. Urine was collected for 24 h on 3 consecutive days. Fosfomycin concentrations in serum and urine were analysed using validated LC-MS/MS. Pharmacokinetics were evaluated using a population model. EudraCT number 2018-000616-25. RESULTS: Twelve patients were included, of whom nine were also administered IV fosfomycin. Data were best described by a two-compartment model with linear elimination and a transit-absorption compartment. Median values for absolute bioavailability and serum half-life were 18% and 2.13 h, respectively. Geometric mean urine concentrations on Days 1, 2 and 3 were above an MIC of 8 mg/L after both oral and IV administration. Quality of life reported on a scale of 1-10 increased from 5.1 to 7.4 (P = 0.001). The average score of UTI symptoms decreased after fosfomycin dosing (by 3.1 points, 95% CI = -0.7 to 7.0, P = 0.10). CONCLUSIONS: Oral fosfomycin at 3 g every 72 h provides plasma and urine concentrations of fosfomycin above the MIC for E. coli. This pharmacokinetic model can be used to develop optimal dosing regimens of fosfomycin in patients with UTI.

Long-term outcome after totally thoracoscopic ablation for atrial fibrillation.

INTRODUCTION: Totally thoracoscopic ablation for symptomatic atrial fibrillation (AF) refractory to drug or catheter based therapy is indicated as a Class 2A recommendation according to latest guidelines. Evidence for long-term rhythm control and stroke reduction is limited. The aim of this study was to report on long-term outcome after totally thoracoscopic ablation. METHODS AND RESULTS: In total 82 consecutive patients were included that underwent totally thoracoscopic ablation including left appendage closure (2012-2013). The primary outcome was freedom from atrial arrhythmia recurrence. Secondary outcomes were survival, freedom from cerebrovascular events, freedom from reablation and definite pacemaker implantation. The mean age was 59.9 ± 8.6 years and 71% were male. The mean CHA2 DS2 -VASc score was 1.2 ± 1.0. The overall freedom from atrial arrhythmia was 60% after a mean follow up of 4.0 ± 0.6 years. Freedom from cerebrovascular events was 98.8% after mean follow-up of 4.4 ± 0.3 years and overall survival was 98.8%, with one noncardiac related death. The observed rate of ischemic stroke, hemorrhagic stroke or transient ischemic attack was 0.3 per 100 patient-years. CONCLUSIONS: Totally thoracoscopic ablation is an effective sustainable rhythm control therapy for AF with a reasonable recurrence rate and low stroke rate when performed in dedicated AF centers.

Thoracoscopic ablation for the treatment of atrial fibrillation: a systematic outcome analysis of a multicentre cohort.

AIMS: To perform a systematic outcome analysis in order to provide cardiologists and general pactitioners with more adequate information to guide their decision making regarding rhythm control. Totally thoracoscopic maze (TTmaze) for the treatment of atrial fibrillation (AF) is recommended as a Class 2a indication mainly based on single centre studies including small patient cohorts and inconsistent lesion sets. METHODS AND RESULTS: We studied consecutive patients undergoing TTmaze in three European referral centres (2012-15). Primary outcome was freedom from atrial tachyarrhythmia (ATA). Secondary outcomes were 30-day complications, the composite endpoint of ischaemic stroke, haemorrhagic stroke or transient ischaemic attack (TIA), all-cause mortality, and predictors of ATA recurrence. Four hundred and seventy-five patients were included, with a mean age of 61 ± 9 years and 69.5% male. The mean CHA2DS2-VASc score was 1.7 ± 1.3. The overall freedom from ATA was 68.8% after a mean follow-up period of 20 ± 9 months. Freedom from ATA was 72.7% for paroxysmal AF, 68.9% for persistent AF, and 54.2% for longstanding persistent AF. Multivariate analysis revealed female gender [hazard ratio (HR): 1.87, P = 0.005], in-hospital AF (HR: 1.95, P = 0.040), longer duration of preoperative AF (HR: 1.06, P = 0.003) and mitral regurgitation (HR: 1.84, P = 0.025) as independent predictors of ATA recurrence. Overall 30-day freedom from any complication was 92.4%. Freedom from cerebrovascular events after mean follow-up of 30 ± 16 months was 98.7% and overall survival was 98.3%. The observed rate of ischaemic stroke, haemorrhagic stroke, or TIA was low (0.5 per 100 patient-years). CONCLUSION: Totally thoracoscopic maze is a safe and effective rhythm control therapy.

Dispersion of Air Bubbles in Isotropic Turbulence.

Bubbles play an important role in the transport of chemicals and nutrients in many natural and industrial flows. Their dispersion is crucial to understanding the mixing processes in these flows. Here we report on the dispersion of millimetric air bubbles in a homogeneous and isotropic turbulent flow with a Taylor Reynolds number from 110 to 310. We find that the mean squared displacement (MSD) of the bubbles far exceeds that of fluid tracers in turbulence. The MSD shows two regimes. At short times, it grows ballistically (∝τ^{2}), while at larger times, it approaches the diffusive regime where the MSD∝τ. Strikingly, for the bubbles, the ballistic-to-diffusive transition occurs one decade earlier than for the fluid. We reveal that both the enhanced dispersion and the early transition to the diffusive regime can be traced back to the unsteady wake-induced motion of the bubbles. Further, the diffusion transition for bubbles is not set by the integral timescale of the turbulence (as it is for fluid tracers and microbubbles), but instead, by a timescale of eddy crossing of the rising bubbles. The present findings provide a Lagrangian perspective towards understanding mixing in turbulent bubbly flows.

Rough-wall turbulent Taylor-Couette flow: The effect of the rib height.

In this study, we combine experiments and direct numerical simulations to investigate the effects of the height of transverse ribs at the walls on both global and local flow properties in turbulent Taylor-Couette flow. We create rib roughness by attaching up to 6 axial obstacles to the surfaces of the cylinders over an extensive range of rib heights, up to blockages of 25% of the gap width. In the asymptotic ultimate regime, where the transport is independent of viscosity, we emperically find that the prefactor of the [Formula: see text] scaling (corresponding to the drag coefficient [Formula: see text] being constant) scales with the number of ribs [Formula: see text] and by the rib height [Formula: see text]. The physical mechanism behind this is that the dominant contribution to the torque originates from the pressure forces acting on the rib which scale with the rib height. The measured scaling relation of [Formula: see text] is slightly smaller than the expected [Formula: see text] scaling, presumably because the ribs cannot be regarded as completely isolated but interact. In the counter-rotating regime with smooth walls, the momentum transport is increased by turbulent Taylor vortices. We find that also in the presence of transverse ribs these vortices persist. In the counter-rotating regime, even for large roughness heights, the momentum transport is enhanced by these vortices.

Mutations in LRRC50 predispose zebrafish and humans to seminomas.

Seminoma is a subclass of human testicular germ cell tumors (TGCT), the most frequently observed cancer in young men with a rising incidence. Here we describe the identification of a novel gene predisposing specifically to seminoma formation in a vertebrate model organism. Zebrafish carrying a heterozygous nonsense mutation in Leucine-Rich Repeat Containing protein 50 (lrrc50 also called dnaaf1), associated previously with ciliary function, are found to be highly susceptible to the formation of seminomas. Genotyping of these zebrafish tumors shows loss of heterozygosity (LOH) of the wild-type lrrc50 allele in 44.4% of tumor samples, correlating with tumor progression. In humans we identified heterozygous germline LRRC50 mutations in two different pedigrees with a family history of seminomas, resulting in a nonsense Arg488* change and a missense Thr590Met change, which show reduced expression of the wild-type allele in seminomas. Zebrafish in vivo complementation studies indicate the Thr590Met to be a loss-of-function mutation. Moreover, we show that a pathogenic Gln307Glu change is significantly enriched in individuals with seminoma tumors (13% of our cohort). Together, our study introduces an animal model for seminoma and suggests LRRC50 to be a novel tumor suppressor implicated in human seminoma pathogenesis.

Influence of CYP2C19 on Helicobacter pylori eradication in Brazilian patients with functional dyspepsia.

The aim of this study was to examine the effect of polymorphisms in the cytochrome P450 (CYP) 2C19 gene (CYP2C19) on the Helicobacter pylori eradication rate in Brazilian patients with functional dyspepsia. Adults diagnosed with functional dyspepsia based on the ROME III criteria and infected with H. pylori were recruited to this study. The patients were subjected to gastrointestinal endoscopy and the H. pylori status was defined when both urease test and histopathology results were negative or positive. The patients were treated with proton pump inhibitor-based triple therapy (omeprazole, amoxicillin, and clarithromycin). CYP2C19*2 and CYP2C19*3 were genotyped by polymerase chain reaction-restriction fragment length polymorphism. One hundred and forty-eight patients (81.8% women) with a mean (± SD) age of 46.1 (12.2) years were included in this study. Based on the CYP2C19 genotypes, the patients were classified as homozygous extensive metabolizer (HomEM; 67.6%), heterozygous extensive metabolizer (HetEM; 26.3%), or poor metabolizer (PM; 6.1%). The H. pylori eradication rates in patients with HomEM, HetEM, and PM were 85.0, 89.7, and 100.0% (P = 0.376), respectively. The included study population comprised a high frequency of patients carrying the HomEM genotype. Although the genotypes of CYP2C19 variants were not statistically significant, the results of this study suggest a possible effect of the PM genotype on the efficacy of H. pylori eradication.

Birt-Hogg-Dube syndrome is a novel ciliopathy.

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disorder where patients are predisposed to kidney cancer, lung and kidney cysts and benign skin tumors. BHD is caused by heterozygous mutations affecting folliculin (FLCN), a conserved protein that is considered a tumor suppressor. Previous research has uncovered multiple roles for FLCN in cellular physiology, yet it remains unclear how these translate to BHD lesions. Since BHD manifests hallmark characteristics of ciliopathies, we speculated that FLCN might also have a ciliary role. Our data indicate that FLCN localizes to motile and non-motile cilia, centrosomes and the mitotic spindle. Alteration of FLCN levels can cause changes to the onset of ciliogenesis, without abrogating it. In three-dimensional culture, abnormal expression of FLCN disrupts polarized growth of kidney cells and deregulates canonical Wnt signalling. Our findings further suggest that BHD-causing FLCN mutants may retain partial functionality. Thus, several BHD symptoms may be due to abnormal levels of FLCN rather than its complete loss and accordingly, we show expression of mutant FLCN in a BHD-associated renal carcinoma. We propose that BHD is a novel ciliopathy, its symptoms at least partly due to abnormal ciliogenesis and canonical Wnt signalling.

Design, synthesis, and biological evaluation of aminopyrazine derivatives as inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2).

Several series of novel non-thiourea-containing aminopyrazine derivatives were designed based on the MK-2 inhibitors 1-(2-aminopyrazin-3-yl)methyl-2-thioureas. These compounds were synthesized and evaluated for their inhibitory activity against MK-2 enzyme in vitro. Compounds with low micromolar to sub-micromolar IC50 values were identified, and several compounds were also found to be active in suppressing the lipopolysaccharide (LPS)-stimulated TNFα production in THP-1 cells with minimum shift compared to their enzyme activity.

A comprehensive method to develop a checklist to increase safety of intra-hospital transport of critically ill patients.

INTRODUCTION: Transport of critically ill patients from the Intensive Care Unit (ICU) to other departments for diagnostic or therapeutic procedures is often a necessary part of the critical care process. Transport of critically ill patients is potentially dangerous with up to 70% adverse events occurring. The aim of this study was to develop a checklist to increase safety of intra-hospital transport (IHT) in critically ill patients. METHOD: A three-step approach was used to develop an IHT checklist. First, various databases were searched for published IHT guidelines and checklists. Secondly, prospectively collected IHT incidents in the LUMC ICU were analyzed. Thirdly, interviews were held with physicians and nurses over their experiences of IHT incidents. Following this approach a checklist was developed and discussed with experts in the field. Finally, feasibility and usability of the checklist was tested. RESULTS: Eleven existing guidelines and five checklists were found. Only one checklist covered all three phases: pre-, during- and post-transport. Recommendations and checklist items mostly focused on the pre-transport phase. Documented incidents most frequently related to patient physiology and equipment malfunction and occurred most often during transport. Discussing the incidents with ICU physicians and ICU nurses resulted in important recommendations such as the introduction of a standard checklist and improved communication with the other departments. This approach resulted in a generally applicable checklist, adaptable for local circumstances. Feedback from nurses using the checklist were positive, the fill in time was 4.5 minutes per phase. CONCLUSION: A comprehensive way to develop an intra-hospital checklist for safe transport of ICU patients to another department is described. This resulted in a checklist which is a framework to guide physicians and nurses through intra-hospital transports and provides a continuity of care to enhance patient safety. Other hospitals can customize this checklist to their own situation using the methods proposed in this paper.

Logarithmic boundary layers in strong Taylor-Couette turbulence.

We provide direct measurements of the boundary layer properties in highly turbulent Taylor-Couette flow up to Re=2×106) (Ta=6.2×10(12)) using high-resolution particle image velocimetry and particle tracking velocimetry. We find that the mean azimuthal velocity profile at the inner and outer cylinder can be fitted by the von Kármán log law u+=1/κ lny+ +B. The von Kármán constant κ is found to depend on the driving strength Ta and for large Ta asymptotically approaches κ≈0.40. The variance profiles of the local azimuthal velocity have a universal peak around y+≈12 and collapse when rescaled with the driving velocity (and not with the friction velocity), displaying a log dependence of y+ as also found for channel and pipe flows.

Scaffold hopping approach towards various AFQ-056 analogs as potent metabotropic glutamate receptor 5 negative allosteric modulators.

The metabotropic glutamate receptor subtype 5 has evolved into a promising target for the treatment of various diseases of the central nervous system, such as Fragile X and L-DOPA induced dyskinesia. One of the most advanced clinical compound is Novartis' AFQ-056 (Mavoglurant), which served us as a template for a scaffold hopping approach, generating a structurally diverse set of potent analogs. Both the limited aqueous solubility and the relatively poor metabolic stability of AFQ-056 were improved with hexahydrocyclopenta[c]pyrrole derivative 54a, which proved to be a valuable candidate for further development.

Rationale and design of the PRAETORIAN trial: a Prospective, RAndomizEd comparison of subcuTaneOus and tRansvenous ImplANtable cardioverter-defibrillator therapy.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are widely used to prevent fatal outcomes associated with life-threatening arrhythmic episodes in a variety of cardiac diseases. These ICDs rely on transvenous leads for cardiac sensing and defibrillation. A new entirely subcutaneous ICD overcomes problems associated with transvenous leads. However, the role of the subcutaneous ICD as an adjunctive or primary therapy in patients at risk for sudden cardiac death is unclear. STUDY DESIGN: The PRAETORIAN trial is an investigator-initiated, randomized, controlled, multicenter, prospective 2-arm trial that outlines the advantages and disadvantages of the subcutaneous ICD. Patients with a class I or IIa indication for ICD therapy without an indication for bradypacing or tachypacing are included. A total of 700 patients are randomized to either the subcutaneous or transvenous ICD (1:1). The study is powered to claim noninferiority of the subcutaneous ICD with respect to the composite primary endpoint of inappropriate shocks and ICD-related complications. After noninferiority is established, statistical analysis is done for potential superiority. Secondary endpoint comparisons of shock efficacy and patient mortality are also made. CONCLUSION: The PRAETORIAN trial is a randomized trial that aims to gain scientific evidence for the use of the subcutaneous ICD compared with the transvenous ICD in a population of patients with conventional ICD with respect to major ICD-related adverse events. This trial is registered at ClinicalTrials.gov with trial ID NCT01296022.

Ultimate turbulent Taylor-Couette flow.

The flow structure of strongly turbulent Taylor-Couette flow with Reynolds numbers up to Re(i)=2×10(6) of the inner cylinder is experimentally examined with high-speed particle image velocimetry (PIV). The wind Reynolds numbers Re(w) of the turbulent Taylor-vortex flow is found to scale as Re(w)∝Ta(1/2), exactly as predicted by Grossmann and Lohse [Phys. Fluids 23, 045108 (2011).] for the ultimate turbulence regime, in which the boundary layers are turbulent. The dimensionless angular velocity flux has an effective scaling of Nu(ω)∝Ta(0.38), also in correspondence with turbulence in the ultimate regime. The scaling of Nu(ω) is confirmed by local angular velocity flux measurements extracted from high-speed PIV measurements: though the flux shows huge fluctuations, its spatial and temporal average nicely agrees with the result from the global torque measurements.

Anatomical perspective on radiofrequency ablation of AV nodal reentry tachycardia after Mustard correction for transposition of the great arteries.

A case of radiofrequency catheter ablation of atrioventricular (AV) nodal reentry tachycardia, in a patient with transposition of the great arteries after venous rerouting according to Mustard, is described. An electroanatomical map of the His and AV nodal region was created from inside the systemic venous atrium. Retrograde mapping of the pulmonary venous atrium was performed and the arterial catheter retracted to a position in close proximity to the venous catheter inside the intraatrial baffle. This position was chosen to deliver radiofrequency current.