Bubble growth analysis during subcooled boiling experiments on-board the international space station: Benchmark image analysis

This work compares four different image processing algorithms for the analysis of image data obtained during the Multiscale Boiling Experiment of ESA, executed on-board the International Space Station. Two separate experimental campaigns have been performed in 2019 and 2020, aiming to investigate boiling phenomena in microgravity, with and without the presence of shear flow and electric field. A heated substrate, at the bottom of the test cell, creates a temperature profile across the liquid bulk above it. A laser beam hits a designated microcavity at the middle of the substrate, to initiate nucleation of a single, isolated bubble. In the presence of shear flow or electric field forces, the bubble slides or detaches respectively, leaving the cavity free for the nucleation and growth of a new bubble. The growth of such a bubble within the prescribed temperature profile is studied for varying experimental conditions (i.e. pressure, heat flux, subcooling temperature) by capturing high speed, black and white video images. The presence of light reflections at random locations around the bubble contour vary with bubble size and population. This, combined with the refraction induced optical distortion of vertical image dimension close to the heater, make the accurate detection of bubbles contour a real challenge. Four research teams, namely the University of Pisa (UNIPI), the Institute of Fluid Mechanics of Toulouse (IMFT), the joint group of Aix Marseille University (AMU) and Kutateladze Institute of Thermophysics (IT), and the joined group of Aristotle University of Thessaloniki (AUTH), Technical University of Darmstadt (TUD) and Foundation of Research and Technology in Crete (FORTH), developed separate specialized algorithms to: a) detect bubble edges and b) use these edges to calculate basic bubble geometrical features, such as contact line diameter, bubble diameter and contact angles. These four different approaches diverge in complexity and concept. In the absence of reference measurements at microgravity conditions, measurements efficiency is evaluated based on the comparison of the estimated bubble geometrical features along with pertinent physical arguments. Results show that the efficiency of each approach varies with the nature of measurement. The studied benchmark dataset is published allowing other research groups to test further their own image processing algorithms.

Decrease in gynecological cancer diagnoses during the COVID-19 pandemic: an Austrian perspective

Background

On March 16, 2020, the federal government of Austria declared a nationwide lockdown due to the COVID-19 pandemic. Since the lockdown, screening examinations and routine checkups have been restricted to prevent the spread of the virus and to increase the hospitals’ bed capacity across the country. This resulted in a severe decline of patient referrals to the hospitals.

Objective

To assess the impact of the COVID-19 pandemic on the rate of newly diagnosed gynecological and breast cancers in Austria.

Methods

Data of 2077 patients from 18 centers in Austria with newly diagnosed gynecological or breast cancer between January and May 2019 and January and May 2020 were collected. Clinical parameters, including symptoms, performance status, co-morbidities, and referral status, were compared between the time before and after the COVID-19 outbreak.

Results

Our results showed a slight increase of newly diagnosed cancers in January and February 2020 as compared with 2019 (+2 and +35%, respectively) and a strong decline in newly diagnosed tumors since the lockdown: −24% in March 2020 versus March 2019, −49% in April 2020 versus April 2019, −49% in May 2020 versus May 2019. Two-thirds of patients diagnosed during the pandemic presented with tumor-specific symptoms compared with less than 50% before the pandemic (p<0.001). Moreover, almost 50% of patients in 2020 had no co-morbidities compared with 35% in 2019 (p<0.001). Patients, who already had a malignant disease, were rarely diagnosed with a new cancer in 2020 as compared with 2019 (11% vs 6%; p<0.001).

Conclusions

The lockdown led to a decreased number of newly diagnosed gynecological and breast cancers. The decreased accessibility of the medical services and postponed diagnosis of potentially curable cancers during the COVID-19 pandemic may be a step backwards in our healthcare system and might impair cancer treatment outcomes. Therefore, new strategies to manage early cancer detection are needed to optimize cancer care in a time of pandemic in the future.

Highly conductive and pure gold nanostructures grown by electron beam induced deposition

This work introduces an additive direct-write nanofabrication technique for producing extremely conductive gold nanostructures from a commercial metalorganic precursor. Gold content of 91 atomic % (at. %) was achieved by using water as an oxidative enhancer during direct-write deposition. A model was developed based on the deposition rate and the chemical composition, and it explains the surface processes that lead to the increases in gold purity and deposition yield. Co-injection of an oxidative enhancer enabled Focused Electron Beam Induced Deposition (FEBID)—a maskless, resistless deposition method for three dimensional (3D) nanostructures—to directly yield pure gold in a single process step, without post-deposition purification. Gold nanowires displayed resistivity down to 8.8 μΩ cm. This is the highest conductivity achieved so far from FEBID and it opens the possibility of applications in nanoelectronics, such as direct-write contacts to nanomaterials. The increased gold deposition yield and the ultralow carbon level will facilitate future applications such as the fabrication of 3D nanostructures in nanoplasmonics and biomolecule immobilization.

Origins of the high 14-helix propensity of cyclohexyl-rigidified residues in beta-peptides

[structure: see text] beta-Peptides containing residues derived from trans-2-aminocyclohexanecarboxylic acid (ACHC) display high population of 14-helical secondary structure in aqueous solution. We show that hydrophobic interactions between cyclohexyl rings are not responsible for this conformation-promoting effect, and that polar groups may be attached to the cyclohexyl ring without diminishing the effect.

New applications of bis(oxazoline) ligands in catalysis: asymmetric 1,2- and 1,4-addition of ZnR(2) to carbonyl compounds

The enantioselective addition of ZnR(2) to aldehydes (1,2) and cyclic enones (1,4) was accomplished using bis(oxazolines) as chiral ligands. The requirement for hydroxymethylene side chains in the ligands strongly suggests that bimetallic catalysts are decisive for high enantiocontrol in these additions. [structure: see text]