Generation of Large Vortex-Free Superfluid Helium Nanodroplets.

Superfluid helium nanodroplets are an ideal environment for the formation of metastable, self-organized dopant nanostructures. However, the presence of vortices often hinders their formation. Here, we demonstrate the generation of vortex-free helium nanodroplets and explore the size range in which they can be produced. From x-ray diffraction images of xenon-doped droplets, we identify that single compact structures, assigned to vortex-free aggregation, prevail up to 10^{8} atoms per droplet. This finding builds the basis for exploring the assembly of far-from-equilibrium nanostructures at low temperatures.

Increasing use of computed tomography scans in the North Denmark Region raises patient safety concern.

PURPOSE: Use of computed tomography (CT) scans raises safety concern as lifetime cumulative ionising radiation exposure is associated with risk of developing malignancies. This study aimed to investigate use of abdominal CT scans in the Danish health care sector. METHODS: Data on abdominal CT scans performed annually in the North Denmark Region between 2005 and 2018 were extracted from the regional registry with emphasis on patients with a medical history of a repeated abdominal CT scan within 28 days. An audit of the medical files was subsequently conducted in 100 randomly selected patient cases to evaluate clinical information being provided, in addition to justification for a repeated abdominal CT scan, and finally if other radiology modalities could have been applied. RESULTS: Number of annually performed abdominal CT scans in this demographically stable regional population increased by a factor 4.3 from 15 in 2005 to 65 in 2018 per 1,000 inhabitants. The audit revealed that 31% of the secondabdominal CT scans within a 28 days period were categorized as either doubtful whether justified or not justified. Moreover, 20% of theCT scans were considered replaceable by ultrasonography. CONCLUSIONS: Annual performance of abdominal CT scans increased fourfold during the 14 years period. This tendency is probably attributable to changes in the Danish health care sector by which CT scan examination are used more frequently aiming at more accelerated patient investigation flow in conjunction with shorter length of hospitalization stay. Alertness is strongly warranted towards the associated risk of cancer due to life-time cumulative ionising radiation exposure by this strategy.

Utilization of delactosed whey permeate for the synthesis of ethyl acetate with Kluyveromyces marxianus.

Ethyl acetate is an important organic solvent and currently produced from fossil carbon resources. Microbial synthesis of this ester from sugar-rich waste could be an interesting alternative. Therefore, synthesis of ethyl acetate by Kluyveromyces marxinanus DSM 5422 from delactosed whey permeate (DWP) was studied in an aerated stirred bioreactor at 40 °C. DWP is mainly composed of residual lactose and minerals. The minerals inhibited yeast growth, as witnessed by an increased lag period, a reduced growth rate, and an extended process duration. All experiments were therefore carried out with diluted DWP. In a series of batch experiments, the pH of iron-deficient DWP medium varied between 4.8 and 5.9. The pH of the cultivation medium significantly influenced cell growth and product syntheses, with the highest ethyl acetate yield of 0.347 g g-1 and lowest by-product formation achieved at pH 5.1. It is likely that this effect is due to pH-dependent iron chelation, which affects the iron bioavailability and the intracellular iron content, thus affecting growth and metabolite synthesis. The viability of yeast cells was always high despite the harsh conditions in DWP medium, which enabled extended usage of the biomass in repeated-batch and fed-batch cultivations. These two culture techniques increased the volume of DWP processed per time by 32 and 84% for the repeated-batch and the fed-batch cultivation, respectively, without a drop of the ester yield. KEY POINTS: • Delactosed whey permeate was converted to ethyl acetate with a high rate and yield. • The formation of ethyl acetate in DWP medium at iron limitation is pH-dependent. • Highly active yeasts from batch processes enabled extension as fed and repeated batch.

Selective catalytic reduction of NOx with ammonia (NH3-SCR) over copper loaded LEV type zeolites synthesized with different templates.

LEV type zeolites were synthesized with four different structure-directing agents and converted to copper loaded NH3-SCR catalysts. The synthesis recipe was found to impact the respective Al population in the two topologically different framework sites in double and single 6-rings, resolvable by 27Al MAS NMR spectroscopy. Hydrothermal stability was found to be related to the silanol concentration, Si/Al ratio, particle size, crystal morphology, crystal defects, external surface area, and microporosity. Catalytic activity in NH3-SCR was dependent on preferential Al siting in the double 6-rings. Levinite synthesized using adamantylamine showed the strongest preference for Al atoms sitting in double 6-ring sites, and showed the highest catalytic turnover frequency. Unfortunately, because of the large crystal size, copper loading of this sample was limited to 0.6 wt% while other samples could be loaded with copper up to 3.3 wt%. An optimum combination of hydrothermal stability and catalytic activity was obtained with N,N'-bis-dimethylpentanediyldiammonium dibromide as structure-directing agent.

On-Chip Direct Laser Writing of PAN-Based Carbon Supercapacitor Electrodes.

The carbonization of polyacrylonitrile (PAN) by direct laser writing to produce microsupercapacitors directly on-chip is reported. The process is demonstrated by producing interdigitated carbon finger electrodes directly on a printed circuit board (PCB), which is then employed to characterize the supercapacitor electrodes. By varying the laser power, the process can be tuned from carbonization to material ablation. This allows to not only convert pristine PAN films into carbon electrodes, but also to pattern and cut away non-carbonized material to produce completely freestanding carbon electrodes. While the carbon electrodes adhere well to the printed circuit board, non-carbonized PAN is peeled off the substrate. Specific capacities as high as 260 µF cm⁻2 are achieved in a supercapacitor with 16 fingers.

Groundwater arsenic content related to the sedimentology and stratigraphy of the Red River delta, Vietnam.

Arsenic (As) is highly toxic and over 100 million people living on the floodplains of Asia are exposed to excessive groundwater As. A very large spatial variability over small distances has been observed in the groundwater As concentrations. Advances in the prediction of the As distribution in aquifers would support drinking water management. The application of remote sensing of geomorphic paleo river features combined with geological, geophysical and archeological data and available groundwater As measurements may be used to predict groundwater As levels in rural areas, as shown by the example from the Red River delta, Vietnam. Groundwater in sediments deposited in the marine environment is low in As, probably due to the precipitation of As in sulfide minerals under anoxic conditions. Groundwater As levels in freshwater alluvial deposits in undisturbed floodplain areas are slightly increased and the highest As concentrations are associated with meander belts. The meander belts remain clearly visible in remote sensing and may well reflect the youngest preserved alluvial sediments. High As levels in the meander belt aquifers are probably related to the availability of highly reactive organic matter and consequent reduction of iron oxyhydroxides and As release. Furthermore, given similar hydrogeological conditions, the extent of flushing of As from the youngest alluvial sands is limited compared to the older Pleistocene sands. Even within abandoned meander belts a high spatial variability of As concentrations was observed. The younger channel belts (<1 ka BP) and old Holocene aquifers below undisturbed floodplain environments deposited during a period with high sea level host groundwater enriched in As. Low As groundwater is found in sandy channel belts deposited during the regression of the sea and in Pleistocene islands preserved within the floodplain. The decisive influence of the depositional environment of the aquifer sediments on groundwater As content is revealed.

The phosphatase PRL-3 affects intestinal homeostasis by altering the crypt cell composition.

Expression of the phosphatase of regenerating liver-3 (PRL-3) is known to promote tumor growth in gastrointestinal adenocarcinomas, and the incidence of tumor formation upon inflammatory events correlates with PRL-3 levels in mouse models. These carcinomas and their onset are associated with the impairment of intestinal cell homeostasis, which is regulated by a balanced number of Paneth cells and Lgr5 expressing intestinal stem cells (Lgr5+ ISCs). Nevertheless, the consequences of PRL-3 overexpression on cellular homeostasis and ISC fitness in vivo are unexplored. Here, we employ a doxycycline-inducible PRL-3 mouse strain to show that aberrant PRL-3 expression within a non-cancerous background leads to the death of Lgr5+ ISCs and to Paneth cell expansion. A higher dose of PRL-3, resulting from homozygous expression, led to mice dying early. A primary 3D intestinal culture model obtained from these mice confirmed the loss of Lgr5+ ISCs upon PRL-3 expression. The impaired intestinal organoid formation was rescued by a PRL inhibitor, providing a functional link to the observed phenotypes. These results demonstrate that elevated PRL-3 phosphatase activity in healthy intestinal epithelium impairs intestinal cell homeostasis, which correlates this cellular mechanism of tumor onset with PRL-3-mediated higher susceptibility to tumor formation upon inflammatory or mutational events.Key messages• Transgenic mice homozygous for PRL-3 overexpression die early.• PRL-3 heterozygous mice display disrupted intestinal self-renewal capacity.• PRL-3 overexpression alone does not induce tumorigenesis in the mouse intestine.• PRL-3 activity leads to the death of Lgr5+ ISCs and Paneth cell expansion.• Impairment of cell homeostasis correlates PRL-3 action with tumor onset mechanisms.

High Throughput Centrifugal Electrospinning of Polyacrylonitrile Nanofibers for Carbon Fiber Nonwovens.

Carbon nanofiber nonwovens are promising materials for electrode or filtration applications; however, their utilization is obviated by a lack of high throughput production methods. In this study, we utilize a highly effective high-throughput method for the fabrication of polyacrylonitrile (PAN) nanofibers as a nonwoven on a dedicated substrate. The method employs rotational-, air pressure- and electrostatic forces to produce fibers from the inner edge of a rotating bell towards a flat collector. We investigate the impact of all above-mentioned forces on the fiber diameter, morphology, and bundling of the carbon-precursor PAN fibers. The interplay of radial forces with collector-facing forces has an influence on the uniformity of fiber deposition. Finally, the obtained PAN nanofibers are converted to carbon nonwovens by thermal treatment.

Low-Temperature Synthesis of Titanium Oxynitride Nanoparticles.

The synthesis of transition metal oxynitrides is complicated by extreme reaction conditions such as high temperatures and/or high pressures. Here, we show an unprecedented solution-based synthesis of narrowly dispersed titanium oxynitride nanoparticles of cubic shape and average size of 65 nm. Their synthesis is performed by using titanium tetrafluoride and lithium nitride as precursors alongside trioctylphosphine oxide (TOPO) and cetrimonium bromide (CTAB) as stabilizers at temperatures as low as 250 °C. The obtained nanoparticles are characterized in terms of their shape and optical properties, as well as their crystalline rock-salt structure, as confirmed by XRD and HRTEM analysis. We also determine the composition and nitrogen content of the synthesized particles using XPS and EELS. Finally, we investigate the applicability of our titanium oxynitride nanoparticles by compounding them into carbon fiber electrodes to showcase their applicability in energy storage devices. Electrodes with titanium oxynitride nanoparticles exhibit increased capacity compared to the pure carbon material.

A new approach for balancing the microbial synthesis of ethyl acetate and other volatile metabolites during aerobic bioreactor cultivations.

Ethyl acetate is an organic solvent with many industrial applications, currently produced by energy-intensive chemical processes based on fossil carbon resources. Ethyl acetate can be synthesized from renewable sugars by yeasts like Kluyveromyces marxianus in aerobic processes. However, ethyl acetate is highly volatile and thus stripped from aerated cultivation systems which complicate the quantification of the produced ester. Synthesis of volatile metabolites is commonly monitored by repeated analysis of metabolite concentrations in both the gas and liquid phase. In this study, a model-based method for quantifying the synthesis and degradation of volatile metabolites was developed. This quantification of volatiles is solely based on repeatedly measured gas-phase concentrations and allows calculation of reaction rates and yields in high temporal resolution. Parameters required for these calculations were determined in abiotic stripping tests. The developed method was validated for ethyl acetate, ethanol and acetaldehyde which were synthesized by K. marxianus DSM 5422 during an iron-limited batch cultivation; it was shown that the presented method is more precise and less time-consuming than the conventional method. The biomass-specific synthesis rate and the yield of ethyl acetate varied over time and exhibited distinct momentary maxima of 0.50 g g‒1h‒1 and 0.38 g g‒1 at moderate iron limitation.

Synthesis of ethyl acetate from glucose by Kluyveromyces marxianus, Cyberlindnera jadinii and Wickerhamomyces anomalus depending on the induction mode.

Ethyl acetate is currently produced from fossil carbon resources. This ester could also be microbially synthesized from sugar-rich wastes of the food industry. Wild-type strains with GRAS status are preferred for such applications. Production of ethyl acetate by wild-type yeasts has been repeatedly reported, but comparative studies with several strains at various induction modes are largely missing. Here, synthesis of ethyl acetate by three yeasts with GRAS status, Kluyveromyces marxianus DSM 5422, Cyberlindnera jadinii DSM 2361 and Wickerhamomyces anomalus DSM 6766, was studied under identical and well-defined conditions in an aerated bioreactor, by inducing the ester synthesis via iron or oxygen limitation. Balancing the ester synthesis was based on measured concentrations of ethyl acetate in the exhaust gas, delivering masses of synthesized ester and synthesis rates in a high temporal resolution. All tested yeasts synthesized ethyl acetate under these conditions, but the intensity varied with the strain and induction mode. The highest yields were achieved under iron limitation with K. marxianus (0.182 g g-1) and under oxygen limitation with W. anomalus (0.053 g g-1). Iron limitation proved to be the better inducer for ester synthesis while oxygen limitation favored ethanol formation. K. marxianus DSM 5422 was the most potent producer of ethyl acetate exhibiting the highest biomass-specific synthesis rate of 0.5 g g-1h-1 under moderate iron limitation.

Thin-disk laser-pumped OPCPA system delivering 4.4 TW few-cycle pulses.

We present an optical parametric chirped pulse amplification (OPCPA) system delivering 4.4 TW pulses centered at 810 nm with a sub-9 fs duration and a carrier-envelope phase stability of 350 mrad. The OPCPA setup pumped by sub-10 ps pulses from two Yb:YAG thin-disk lasers at 100 Hz repetition rate is optimized for a high conversion-efficiency. The terawatt pulses of the OPCPA are utilized for generating intense extreme ultraviolet (XUV) pulses by high-order harmonic generation, achieving XUV pulse energies approaching the microjoule level.

Correction: Generation and Characterisation of Cisplatin-Resistant Non-Small Cell Lung Cancer Cell Lines Displaying a Stem-Like Signature.

[This corrects the article DOI: 10.1371/journal.pone.0054193.].

Anti-interleukin-5 therapy (mepolizumab) in life-threatening asthma attack: A case-based discussion.

We report about a case of a compassionate off-label use of the anti-interleukin-5-agent mepolizumab in a ventilated patient with life-threatening asthma attack in eosinophilic asthma. The patient suffered from severe eosinophilic asthma and was transmitted to our hospital with an asthma attack and a life-threatening respiratory state under ventilation. Since high dose steroids had not yielded a sufficient respiratory improvement mepolizumab was administered subcutaneously. After administration of mepolizumab respiratory state and ventilation parameter improved significantly. Two days after administration the patient was weaned could be extubated 8 days later and recovered completely from the asthma attack. The presented clinical case is suggestive of future clinical trials or registry studies to evaluate potential clinical benefits of anti-interleukin-5 treatment in patients with severe exacerbations of eosinophilic asthma.

Modeling population dynamics in a microbial consortium under control of a synthetic pheromone-mediated communication system.

Microbial consortia can be used to catalyze complex biotransformations. Tools to control the behavior of these consortia in a technical environment are currently lacking. In the present study, a synthetic biology approach was used to build a model consortium of two Saccharomyces cerevisiae strains where growth and expression of the fluorescent marker protein EGFP by the receiver strain is controlled by the concentration of α-factor pheromone, which is produced by the emitter strain. We have developed a quantitative experimental and theoretical framework to describe population dynamics in the model consortium. We measured biomass growth and metabolite production in controlled bioreactor experiments, and used flow cytometry to monitor changes of the subpopulations and protein expression under different cultivation conditions. This dataset was used to parameterize a segregated mathematical model, which took into account fundamental growth processes, pheromone-induced growth arrest and EGFP production, as well as pheromone desensitization after extended exposure. The model was able to predict the growth dynamics of single-strain cultures and the consortium quantitatively and provides a basis for using this approach in actual biotransformations.