Development of a spectrometer using a continuous wave distributed feedback quantum cascade laser operating at room temperature for the simultaneous analysis of N2O and CH4 in the Earth's atmosphere

We report on the development and performance of a gas sensor based on a distributed feedback quantum cascade laser operating in continuous wave at room temperature for simultaneous measurement of nitrous oxide (N(2)O) and methane (CH(4)) concentrations at ground level. The concentrations of the gases are determined by a long path infrared diode laser absorption spectroscopy. The long-term stability of the instrument is evaluated using the Allan variance technique. A preliminary evaluation of the instrument performance is realized by in situ measurements of N(2)O and CH(4) concentrations at ground level during 1 day. The sensor has also been applied to study the time response of N(2)O concentrations to a fertilizer addition in a soil sample and for the comparison between various types of soils.     

Tailoring Pyro- and Orthophosphate Species to Enhance Stem Cell Adhesion to Phosphate Glasses

Phosphate-based glasses (PBGs) offer significant therapeutic potential due to their bioactivity, controllable compositions, and degradation rates. Several PBGs have already demonstrated their ability to support direct cell growth and in vivo cytocompatibility for bone repair applications. This study investigated development of PBG formulations with pyro- and orthophosphate species within the glass system (40 − x)P₂O₅·(16 + x)CaO·20Na₂O·24MgO (x = 0, 5, 10 mol%) and their effect on stem cell adhesion properties. Substitution of phosphate for calcium revealed a gradual transition within the glass structure from Q² to Q⁰ phosphate species. Human mesenchymal stem cells were cultured directly onto discs made from three PBG compositions. Analysis of cells seeded onto the discs revealed that PBG with higher concentration of pyro- and orthophosphate content (61% Q¹ and 39% Q⁰) supported a 4.3-fold increase in adhered cells compared to glasses with metaphosphate connectivity (49% Q² and 51% Q¹). This study highlights that tuning the composition of PBGs to possess pyro- and orthophosphate species only, enables the possibility to control cell adhesion performance. PBGs with superior cell adhesion profiles represent ideal candidates for biomedical applications, where cell recruitment and support for tissue ingrowth are of critical importance for orthopaedic interventions.     

Reconstruction of Grenfell Tower fire. Part 1: Lessons from observations and determination of work hypotheses

The Grenfell Tower fire occurred on 14 June 2017, killing 72 people. The pattern and speed of vertical and horizontal fire spread characterize this catastrophic event. Plentiful video and photographic data of the fire spread available has been carefully verified and concatenated into a database. The verified data have been superimposed on a projection of the Grenfell Tower in order to track the development of the fire. The surface that is unburnt, burning, or extinguished, as well as the presence of internal fire at any given location, is thus recorded for the duration of the fire. An analysis of the results showed that the initial vertical propagation can be divided into three phases. After the façade ignited at the fourth floor, vertical propagation over time is linear, with a vertical fire spread rate of around 3.5 m/min until the fire reached the sixth floor. Then fire propagation decelerated. Finally, fire spread accelerated with a power four dependence. The maximum vertical fire spread rate was around 8 m/min as the fire reached the crown at the top of the building. Horizontal spread proved to be greatest at the level of the crown (0.293 ± 0.005 m/min). There is a linear relationship between speed of horizontal fire spread and height. These correlations and observations yield important conclusions, and eight different hypotheses capable of explaining the global behaviour of the fire are suggested.     

Magnetic and Photocatalytic Activity of Pure BaFe12O19 and BaFe12O19-TiO2 Hexagonal Ferrite Nanocomposites

Journal of Superconductivity and Novel Magnetism - Hard hexagonal barium ferrite BaFe12O19 (BaM), as well as core–shell structure BaFe12O19-TiO2 composite nanoparticles, was successfully...     

Identification of a New QTL Region on Mouse Chromosome 1 Responsible for Male Hypofertility: Phenotype Characterization and Candidate Genes

Male fertility disorders often have their origin in disturbed spermatogenesis, which can be induced by genetic factors. In this study, we used interspecific recombinant congenic mouse strains (IRCS) to identify genes responsible for male infertility. Using ultrasonography, in vivo and in vitro fertilization (IVF) and electron microscopy, the phenotyping of several IRCS carrying mouse chromosome 1 segments of Mus spretus origin revealed a decrease in the ability of sperm to fertilize. This teratozoospermia included the abnormal anchoring of the acrosome to the nucleus and a persistence of residual bodies at the level of epididymal sperm midpiece. We identified a quantitative trait locus (QTL) responsible for these phenotypes and we have proposed a short list of candidate genes specifically expressed in spermatids. The future functional validation of candidate genes should allow the identification of new genes and mechanisms involved in male infertility.     

Reducing Affective Responses to Surgical Images and Videos Through Stylization

We present the first empirical study on using colour manipulation and stylization to make surgery images/videos more palatable. While aversion to such material is natural, it limits many people's ability to satisfy their curiosity, educate themselves and make informed decisions. We selected a diverse set of image processing techniques to test them both on surgeons and lay people. While colour manipulation techniques and many artistic methods were found unusable by surgeons, edge-preserving image smoothing yielded good results both for preserving information (as judged by surgeons) and reducing repulsiveness (as judged by lay people). We then conducted a second set of interview with surgeons to assess whether these methods could also be used on videos and derive good default parameters for information preservation. We provide extensive supplemental material at osf.io/4pfes/ .     

Gold-Catalyzed Migration of Propargyl Acetate as an Entry into the Total Synthesis of Natural Products

Gold catalysis has emerged over the last two decades as a protocole of choice for the efficient and selective activation of a variety of organic functional groups. This has served to the total synthesis of natural products at several occasions. In this context, the gold-catalyzed migration (1,2- or 1,3-) of propargyl acetates has been particularly used. This review highlights these different synthetic developments which are presented according to the involved mechanisms.