Self-expandable metallic stents in oesophago-respiratory fistulas treatment in neoplasms — case reports and literature review

Self-expandable metallic stents (SEMS) insertion to the oesophagus is the method of choice in palliative treatment of malignant oesophago-respiratory fistulas (ERF). ERF evolve as a result of 0.2−5% of advanced oesopghageal or lung cancer. They also appear after radiotherapy. EFR are serious and lethal complications. SEMS insertion is an effective, safe, technically simple and minimally invasive solution. Potential complications of SEMS include thoracic pain, bleeding, perforation, stent migration, tumour overgrowth or ingrowth and food bolus impaction. The article presents three cases of patients with advanced lung cancer with EFR subjected to SEMS insertion procedure in our centre.Self-expandable metallic stents (SEMS) insertion to the oesophagus is the method of choice in palliative treatment of malignant oesophago-respiratory fistulas (ERF). ERF evolve as a result of 0.2−5% of advanced oesopghageal or lung cancer. They also appear after radiotherapy. EFR are serious and lethal complications. SEMS insertion is an effective, safe, technically simple and minimally invasive solution. Potential complications of SEMS include thoracic pain, bleeding, perforation, stent migration, tumour overgrowth or ingrowth and food bolus impaction. The article presents three cases of patients with advanced lung cancer with EFR subjected to SEMS insertion procedure in our centre

A large-scale, regular intergalactic magnetic field associated with Stephan's Quintet?

Regular magnetic fields are frequently found within and in the outskirts of galaxies, but their presence, properties, and origin has not yet been established for galaxy groups. On the basis of broadband radio polarimetric imaging with the Westerbork Synthesis Radio Telescope (WSRT), we made use of Rotation Measure Synthesis to disentangle contributions from magnetic fields on various scales for several polarised radio sources inside, behind, or in the vicinity of the Stephan's Quintet (HCG92, SQ). We recognise the signature of a large-scale, genuinely regular, magnetised screen, seemingly constrained to the Quintet itself. Although we cannot exclude a contribution from the Milky Way, our analysis favours a magnetic structure within the SQ system. If indeed associated with the galaxy group in question, it would span a volume of at least $60\,\times\,40\,\times\,20\,\mathrm{kpc}$ and have a strength at least as high as that previously detected within large spiral galaxies. This field would then surpass the extent of any other known galactic, regular magnetic fields, have a considerable strength of a few microgauss, and would be the first known example of such a structure in a galaxy system other than a galaxy pair. Several other explanations are also presented and evaluated.Comment: 13 pages, 7 figures, 3 table

A novel and potentially scalable CVD-based route towards SnO 2:Mo thin films as transparent conducting oxides

From Springer Nature via Jisc Publications RouterHistory: received 2021-03-06, accepted 2021-06-15, registration 2021-06-16, pub-electronic 2021-07-12, online 2021-07-12, pub-print 2021-10Publication status: PublishedAbstract: In this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of 7.3×10-3Ωcm, compared to pure SnO2 films with resistivities of 4.30×10-2Ωcm. Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

Probing the electronic transport on the reconstructed Au/Ge(001) surface

By using scanning tunnelling potentiometry we characterized the lateral variation of the electrochemical potential $\mu _{ec}$ on the gold-induced Ge(001)-c(8 × 2)-Au surface reconstruction while a lateral current flows through the sample. On the reconstruction and across domain boundaries we find that $\mu _{ec}$ shows a constant gradient as a function of the position between the contacts. In addition, nanoscale Au clusters on the surface do not show an electronic coupling to the gold-induced surface reconstruction. In combination with high resolution scanning electron microscopy and transmission electron microscopy, we conclude that an additional transport channel buried about 2 nm underneath the surface represents a major transport channel for electrons

Controlled growth of hexagonal gold nanostructures during thermally induced self-assembling on Ge(001) surface

Nano-sized gold has become an important material in various fields of science and technology, where control over the size and crystallography is desired to tailor the functionality. Gold crystallizes in the face-centered cubic (fcc) phase, and its hexagonal closed packed (hcp) structure is a very unusual and rare phase. Stable Au hcp phase has been reported to form in nanoparticles at the tips of some Ge nanowires. It has also recently been synthesized in the form of thin graphene-supported sheets which are unstable under electron beam irradiation. Here, we show that stable hcp Au 3D nanostructures with well-defined crystallographic orientation and size can be systematically created in a process of thermally induced self-assembly of thin Au layer on Ge(001) monocrystal. The Au hcp crystallite is present in each Au nanostructure and has been characterized by different electron microscopy techniques. We report that a careful heat treatment above the eutectic melting temperature and a controlled cooling is required to form the hcp phase of Au on a Ge single crystal. This new method gives scientific prospects to obtain stable Au hcp phase for future applications in a rather simple manner as well as redefine the phase diagram of Gold with Germanium

Atomically dispersed copper sites in a metal-organic framework for reduction of nitrogen dioxide

Metal–organic framework (MOF) materials provide an excellent platform to fabricate single-atom catalysts due to their structural diversity, intrinsic porosity, and designable functionality. However, the unambiguous identification of atomically dispersed metal sites and the elucidation of their role in catalysis are challenging due to limited methods of characterization and lack of direct structural information. Here, we report a comprehensive investigation of the structure and the role of atomically dispersed copper sites in UiO-66 for the catalytic reduction of NO2 at ambient temperature. The atomic dispersion of copper sites on UiO-66 is confirmed by high-angle annular dark-field scanning transmission electron microscopy, electron paramagnetic resonance spectroscopy, and inelastic neutron scattering, and their location is identified by neutron powder diffraction and solid-state nuclear magnetic resonance spectroscopy. The Cu/UiO-66 catalyst exhibits superior catalytic performance for the reduction of NO2 at 25 °C without the use of reductants. A selectivity of 88% for the formation of N2 at a 97% conversion of NO2 with a lifetime of >50 h and an unprecedented turnover frequency of 6.1 h–1 is achieved under nonthermal plasma activation. In situ and operando infrared, solid-state NMR, and EPR spectroscopy reveal the critical role of copper sites in the adsorption and activation of NO2 molecules, with the formation of {Cu(I)···NO} and {Cu···NO2} adducts promoting the conversion of NO2 to N2. This study will inspire the further design and study of new efficient single-atom catalysts for NO2 abatement via detailed unravelling of their role in catalysis

Residual resistometry of atomic ordering kinetics in NiAl intermetalics compound.

Kinetics of "order - order" reactions in B2-ordered Ni50,5Al49,5 intermetallic was examined by means of quasiresidual resistometry. Isothermal relaxations of quasiresual electrical resistance of the sample (measured after having quenched the sample in liquid nitrogen) were associated with corresponding relaxations of the concentration of antisite defects (proportional to the long-range order parameter). Detailed description of the experimental results is preceded by short analysis of crystalline structure of metals and an outline of a model of the relationship between residual electrical resistance of alloys and the chemical order. Activation energies were determined for both ordering (E=2,70(7) eV) and disordering processes ( E=2,52(21)eV) occurring in the material. These energies are lower than the activation energy for Ni difussion process (3,0 eV), but somewhat higher than the ones determined for "order - order" processes in the same compound by means of "in situ" resistometry.Long relaxation times observed in the experiment find their justification in literature - efficiency of atomic jumps is rather small because atoms are performing frequent returning jumps from the antisite to right positions.W pracy badana była kinetyka procesów "porządek - porządek" w związkumiędzymetalicznym Ni50,5Al49,5, charakteryzującym się nadstrukturą B2, metodą rezystometrii kwaziresztkowej. Izotermiczne procesyrelaksacji elektrycznego oporu kwaziresztkowego próbki (mierzone po zanurzeniu próbki w ciekłym azocie) zostały powiązane z relaksacją koncentracji defektów antystrukturalnych (proporcjonalnej do parametru uporządkowania atomowego dalekiego zasięgu).Szczegółowy opis eksperymentu i jego wyników poprzedzony jest krótką analizą krystalicznej budowy metali oraz opis zachowania oporu elektrycznego w stopach metali ze szczególnym uwzględnieniem wpływu uporządkowania atomowego dalekiego zasięgu.Wyznaczone zostały energie aktywacji procesu porządkowania (E=2,70(7) eV)oraz zmniejszania uporządkowania atomowego dalekiego zasięgu (E=2,52(21)eV), które mają miejsce w badanym meteriale. Energie te są niższe niż energia aktywacji procesu dyfuzji Ni (3,0eV), jednak nieznacznie wyższe od energii aktywacji procesu "porządek - porządek" tego samego związku wyznaczonej metodę rezystometrii "in situ". Długie czasy relaksacji zaobserwowane w eksperymencie znajdują swojeuzasadnienie w literaturze, będąc wynikiem niskiej efektywnościprzeskoków atomów w tworzeniu defektów - atomy preferują częste skoki powrotne z pozycji antystrukturalnej na własną podsieć

"Order–order" kinetics in Ni_{50.5}Al_{49.5} single crystal by quasi-residual resistometry

Kinetics of "order–order" reactions in B2-ordered $Ni_{50.5}Al_{49.5}$ intermetallic was examined by means of quasi-residual resistometry. Isothermal relaxations of quasi-residual electrical resistance of the sample, measured in liquid nitrogen bath, were associated with corresponding relaxations of the concentration of antisite defects, proportional to the long-range order parameter. Similarly as in the case of previous "in situ" experiments, the observed relaxations were very sluggish with relatively low activation energies: $E_{A}^{(ord)} = (2.37 \pm 0.10)$ eV for ordering and $E_{A}^{(dis)} = (1.93 \pm 0.19)$ eV for disordering process. These energies are lower than the activation energy for Ni self-diffusion in NiAl (3.0 eV), but somewhat higher than the one previously determined by means of "in situ" resistometry for "order–order" processes in $Ni_{50.5}Al_{49.5}$. The origin of low relaxation rates observed in the experiment has recently been elucidated by atomistic Kinetic Monte Carlo (KMC) simulations in terms of low disordering efficiency of atomic jumps in triple-defect B2-ordering binary systems