Hiatoplasty with crura buttressing versus hiatoplasty alone during laparoscopic sleeve gastrectomy

Introduction. In obese patients with hiatal hernia (HH), laparoscopic sleeve gastrectomy (LSG) with cruroplasty is an option but use of prosthetic mesh crura reinforcement is debated. The aim was to compare the results of hiatal closure with or without mesh buttressing during LSG. Methods. Gastroesophageal reflux disease (GERD) was assessed by the Health-Related Quality of Life (GERD-HRQL) questionnaire before and after surgery in two consecutive series of patients with esophageal hiatus ≤ 4 cm2. After LSG, patients in group A (12) underwent simple cruroplasty, whereas in group B patients (17), absorbable mesh crura buttressing was added. Results. At mean follow-up of 33.2 and 18.1 months for groups A and B, respectively (p = 0 006), the mean preoperative GERD-HRQL scores of 16.5 and 17.7 (p = 0 837) postoperatively became 9.5 and 2.4 (p = 0 071). In group A, there was no difference between pre- and postoperative scores (p = 0 279), whereas in group B, a highly significant difference was observed (p = 0 002). The difference (Δ) comparing pre- and postoperative mean scores between the two groups was significantly in favor of mesh placement (p = 0 0058). Conclusions. In obese patients with HH and mild-moderate GERD, reflux symptoms are significantly improved at medium term follow-up after cruroplasty with versus without crura buttressing during LSG.Introduction. In obese patients with hiatal hernia (HH), laparoscopic sleeve gastrectomy (LSG) with cruroplasty is an option but use of prosthetic mesh crura reinforcement is debated. The aim was to compare the results of hiatal closure with or without mesh buttressing during LSG. Methods. Gastroesophageal reflux disease (GERD) was assessed by the Health-Related Quality of Life (GERD-HRQL) questionnaire before and after surgery in two consecutive series of patients with esophageal hiatus ≤ 4 cm2. After LSG, patients in group A (12) underwent simple cruroplasty, whereas in group B patients (17), absorbable mesh crura buttressing was added. Results. At mean follow-up of 33.2 and 18.1 months for groups A and B, respectively (p = 0 006), the mean preoperative GERD-HRQL scores of 16.5 and 17.7 (p = 0 837) postoperatively became 9.5 and 2.4 (p = 0 071). In group A, there was no difference between pre- and postoperative scores (p = 0 279), whereas in group B, a highly significant difference was observed (p = 0 002). The difference (Δ) comparing pre- and postoperative mean scores between the two groups was significantly in favor of mesh placement (p = 0 0058). Conclusions. In obese patients with HH and mild-moderate GERD, reflux symptoms are significantly improved at medium term follow-up after cruroplasty with versus without crura buttressing during LSG

Laparoscopic Left Adrenalectomy with Submesocolic and Retropancreatic Approach

Introduction: The safety and efficacy of laparoscopic transperitoneal lateral adrenalectomy and retroperitoneoscopic adrenalectomy have been reported. The aim is to report the authors’ experience in laparoscopic left adrenalectomy with an alternative transperitoneal submesocolic and retropancreatic approach with patient supine

Tratado teórico y práctico de la fabricación de pintados ó indianas

Conté: 1. De la economia, situación, maquinaria, utensilios y materiales necesarios para esta fabricación. 2. De la fabricación, dividida en tres clases, á baños calientes, frios y mixta, cuyas clases entrañan cuantos descubrimientos se han hecho hasta el día en esta fabricaciónPaper fet a m

Functionalization of Indium Oxide for Empowered Detection of CO2 over an Extra-Wide Range of Concentrations

Carbon capture, storage, and utilization have becomefamiliar termswhen discussing climate change mitigation actions. Such endeavorsdemand the availability of smart and inexpensive devices for CO2 monitoring. To date, CO2 detection relies on opticalproperties and there is a lack of devices based on solid-state gassensors, which can be miniaturized and easily made compatible withInternet of Things platforms. With this purpose, we present an innovativesemiconductor as a functional material for CO2 detection.A nanostructured In2O3 film, functionalizedby Na, proves to enhance the surface reactivity of pristine oxideand promote the chemisorption of even rather an inert molecule asCO(2). An advanced operando equipment basedon surface-sensitive diffuse infrared Fourier transform is used toinvestigate its improved surface reactivity. The role of sodium isto increase the concentration of active sites such as oxygen vacanciesand, in turn, to strengthen CO2 adsorption and reactionat the surface. It results in a change in film conductivity, i.e.,in transduction of a concentration of CO2. The films exhibitexcellent sensitivity and selectivity to CO2 over an extra-widerange of concentrations (250-5000 ppm), which covers most indoorand outdoor applications due to the marginal influence by environmentalhumidity

Evidence for a different electronic configuration as a primary effect during compression of orthorhombic perovskites: The case of NdM3+O3 (M=Cr,Ga)

(Mg,Fe)SiO3 perovskite is the most abundant mineral of the Earth’s lower mantle, and compounds with the perovskite structure are perhaps the most widely employed ceramics. Hence, they attract both geophysicists and material scientists. Several investigations attempted to predict their structural evolution at high pressure, and recent advancements highlighted that perovskites having ions with the same formal valence at both polyhedral sites (i.e., 3+:3+) define different compressional patterns when transition metal ions (TMI) are involved. In this study, in situ high-pressure synchrotron XRD measurements coupled with ab initio simulations of the electronic population of NdCrO3 perovskite are compared with the compressional feature of NdGaO3. Almost identical from a steric point of view (Cr3+ and Ga3+ have almost the same ionic radius), the different electronic configuration of octahedrally coordinated ions – which leads to a redistribution of electrons at the 3d orbitals for Cr3+ – allows the crystal field stabilization energy (CFSE) to act as a vehicle of octahedral softening in NdCrO3 or it turns octahedra into rigid units when CFSE is null as in NdGaO3. Besides to highlight that different electronic configurations can act as a primary effect during compression of perovskite compounds, our findings have a deep repercussion on the way the compressibility of perovskites have to be modeled

PEROVSKITES. FROM PIGMENTS TO MULTIFERROICS, TO THE DISCOVERY OF THE LOCKED-TILT PEROVSKITES

Superconductors, non-toxic inorganic pigments, sensitizers in dye-sensitized solar cells (DSSCs), semiconductors, and multiferroics are just a few examples of the broad range of uses for which ceramics with perovskite structure are employed. In its aristotype form the ABO3 perovskite structure is cubic (s.g. Pm-3m) with A cations located at the center of dodecahedral sites defined by a three-dimensional array of corner-sharing BO6 octahedra. This polyhedral arrangement makes the perovskite structure extremely flexible. Indeed, due to changes in the chemical nature of A and B cations as well as on temperature and pressure conditions, the ideal cubic symmetry is often lowered, and the resulting structure is described by a combination of tilts and distortion of the BO6 octahedra (Mitchell, 2002). In this contribution, a series of case studies on the interplay among structural characterizations, coloration mechanisms, and technological prospects of ceramics with perovskite structure are outlined. Starting from the Crdoped (Y,REE)AlO3 (YAP) case, i.e. the only system manufactured at the industrial scale and currently used as ceramic red pigment (Ardit et al., 2016), the first case study (i.e., a X-ray powder diffraction and electronic absorption spectroscopy combined investigation) is focused on the effects due to the Al↔Cr substitution at the B octahedral site of the YAP structure, which cause a degree of structural relaxation around Cr3+ that, whether compared with other Cr-bearing structures, is relatively low (Cruciani et al., 2009). The concept of crystal field stabilization energy CFSE, closely related with that of structural relaxation (Burns, 1993), will lead to the second case study where in situ high-pressure synchrotron XRD measurements coupled with ab initio simulations of the electronic population of the orthorhombic NdCrO3 perovskite are compared with the compressional feature of NdGaO3 (high-tech ceramics applied as interconnector of solid oxide fuel cells (SOFC), substrate for high-Tc superconductors (HTSC), colossal magnetoresistive (CMR) film epitaxy, and so on). The different electronic configuration of octahedrally coordinated Cr3+ and Ga3+ ions that leads to a redistribution of electrons at the 3d orbitals for Cr3+ allows the CFSE at octahedral sites to act as vehicle of octahedral softening in NdCrO3 or it turns octahedra into rigid units when CFSE is null as in NdGaO3. The third (and last) case study deals with the first finding of a perovskite characterized by absence of changes in the octahedral tilting and a volume reduction with pressure exclusively controlled by an isotropic polyhedral compression (Ardit et al., 2017). A synchrotron structural investigation at high-pressure sets YAl0.25Cr0.75O3 as the prototype of the so-called locked-tilt perovskites. Besides to reveal a new P-T thermodynamic scenario in the world of perovskite compounds, such a freezing of the octahedral rotations offers a new (and antithetic, keeping in mind that oxygen rotations are strongly coupled to the functional properties of perovskite compounds) perspective on the research of new functional materials (e.g., ferroelectrics and multiferroics). For example, the mutual interaction between layers of octahedrally tilted perovskites subjected to an external perturbation can be easily tuned whether one of the layers is a locked-tilt perovskite. Ardit, M., Cruciani, G., Dondi, M., Zanelli, C. (2016): Pigments based on perovskite. In: “Perovskites and related mixed oxides: Concepts and applications”, P. Granger, V. Parvulescu, S. Kaliaguine, W. Prellier, eds. Wiley-VCH, 259-288. Ardit, M., Dondi, M., Cruciani, G. (2017): Locked octahedral tilting in orthorhombic perovskites: At the boundary of the general rule predicting phase transitions. Phys. Rev. B, 95, 024110. Burns, R.G. (1993): Mineralogical application of crystal field theory. 2nd Ed. Cambridge University Press, 551 p. Cruciani, G., Ardit, M., Dondi, M., Matteucci, F., Blosi, M., Dalconi, M.C., Albonetti, S. (2009): Structural relaxation around Cr3+ in YAlO3-YCrO3 perovskites from electron absorption spectra. J. Phys. Chem. A, 113, 13772-13778. Mitchell, R.H. (2002): Perovskites: Modern and Ancient. Almaz Press., Thunder Bay, Ontario, 316 p

Micronization of ceramic pigments: the mineralogist’s viewpoint on comminution rate and amorphisation

Since its advent (a decade ago) the Drop on Demand Ink-Jet Printing (DOD-IJP) is increasingly used worldwide to decorate ceramic tiles (Digital Decoration, DD). The introduction of this technique has forced pigment manufacturers towards a paradigm shift: the way colorants are applied onto the ceramic tiles and the technological requirements for pigments and dyes are completely changed. Indeed, the finished product is no longer a powdered colorant, but a micronized pigment dispersed in a carrier, namely an ink. Ceramic inks are produced by means of a high-energy ball milling process to reduce the particles of pigment from micrometric to submicronic size (i.e., micronization down to median diameters, d50, of 0.2-0.5 μm). Along with several advantages (non-contact decoration, high-quality images, print on textured surfaces, less wastage of inks and additives, and no need for screens), DOD-IJP also entails strict requirements, among which ensuring that >99% of the pigment particles are less than 1 μm in diameter [1]. Being mainly dependent on the specific energy input (i.e., on the energy supplied to the grinding chamber in relation to the mass of product), pigment micronization down to the requested particle size proves to be the most energy-consuming comminution process per unit weight of product [2]. It derives that comminution of ceramic pigments is a key issue for ink production, which has strong repercussions on color strength, mechanical properties and resistance to amorphization of the pigment crystal structure. Based on size-energy relationships in comminution processes, as well as on the concept of pressure-induced amorphization in crystal structures, this contribution is aimed at providing a new viewpoint on the micronization effects during the comminution of ceramic pigments. Experimental data on the comminution of representative industrial ceramic pigments (with zircon-, rutile-, spinel-type crystal structure) as micronized in a pilot plant have been selected from literature. Besides to confirm the suitability of the Rittinger's law in the submicrometric range of particles size, the energy dissipated by the comminution process is found to be proportional to the number of iterations during the micronization. In addition, different rates of micronization of three spinel-type pigments (CoFe2O4, CoAl2O4, and Co0.75Fe0.75Cr1.5O4) point out a new relationship between grindability of a ceramic pigment and its density (or bulk modulus). A new interpretation on the degree of ceramic pigments amorphization after prolonged comminution is also conceived. [1] Hutchings I. 2010. Ink-jet printing for the decoration of ceramic tiles: technology and opportunities. In: Proceedings of the 12th World Congress on Ceramic Tile Quality, QUALICER, Castellón (Spain). 1-16. [2] Wang Y. & Forssberg E. 2007. Enhancement of energy efficiency for mechanical production of fine and ultra-fine particles in comminution. China Particuol., 5, 193-201

The ferroelastic phase transition in ZSM-5 zeolites: chemistry vs. thermodynamic

In analogy to ferromagnetism and ferroelectricity, ferroelasticity can be defined by large elastic nonlinearities that lead to elastic hysteresis behavior. Ferroelasticity produces interfacial twin walls where localized effects (e.g. superconducting twin boundaries and ferroelectricity) cannot be observed at the bulk scale (i.e. different forces act on the atoms at the local and bulk scales).1 We thus have an intermediate structural length scale - the mesostructure. Actually, microstructural features modify the ideal crystal structure of a crystalline material and often lead to phase transitions that change its crystallographic symmetry. These ferroelastic phase transitions can be described through Landau-type theories at both the crystal structure and mesostructure levels.2 Zeolite Socony Mobil-5 (ZSM-5), with MFI framework topology, belongs to the pentasil zeolite family and is characterized by a three-dimensional pore system formed by two intersecting sets of tubular channels delimited by 10-membered rings of tetrahedra: the so-called straight channel parallel to the [010] direction and the sinusoidal channel parallel to the [100] direction. Its unique microporous structure coupled with high surface area, mechanical, thermal, biological, and chemical stability has promoted ZSM-5 as one of the most employed synthetic zeolites in catalysis and adsorption processes.e.g.3 The as-synthesized template-containing form of ZSM-5 exhibits the orthorhombic topological symmetry (s.g. Pnma). After thermal treatment the crystal symmetry is lowered to the monoclinic P21/n. Upon heating ZSM-5 is known to experience a displacive m↔o phase transition (i.e., from the monoclinic P21/n to the orthorhombic Pnma) at different transition temperatures (Tc) depending on framework composition (i.e. the Si/Al ratio), lattice defect density, as well as amount and physical-chemical properties of guest molecules. Reported for the first time by Wu et al.,4 it has been shown that aggregates of twin domains of the monoclinic framework reversibly displace into an orthorhombic single crystal upon heating, suggesting that the ZSM-5 monoclinic polymorph has the features of a ferroelastic material.5 According to the Landau theory, the temperature evolution of a ZSM-5 (Si/Al = 140) unloaded and has been characterized through the analysis of the spontaneous strain variation before and after the adsorption of organic contaminants (i.e. toluene, 1,2-dichloroethane, methyl-tert-buthyl-ether, and binary mixtures of them).6,7 The first main result is that all the investigated samples undergo a m↔o phase transition with a tricritical character (i.e. between second order and first order). This fact is of relevance because the strain fluctuations within the domain structure of materials showing tricritical phase transitions are generally less relevant than those associated to truly second order transitions.8 Secondly, the adsorption of different organic contaminants strongly affect the Tc and the thermodynamic features related with the phase transition. Indeed, the excess enthalpy part of the free-energy expansion (which derives from the coefficients of the Landau potential) is strictly related with the enthalpy of guest molecules adsorption (ΔHad). Although the dependence among Tc, Si/Al ratio, and the enthalpy change ΔH related to the ferroelastic m↔o phase transition in ZSM-5 compounds has been already outlined,9 the thermodynamic processes that govern these relationships at both the crystal structure and mesostructure levels have to be still disclosed. For this reason, in this contribution the ferroelastic m↔o phase transition in a ZSM-5 (with Si/Al ratio of 250) and a silicalite (Si/Al ratio → ∞) synthesized by a common procedure has been monitored through the combination of in-situ X-ray powder diffraction at high-temperature and calorimetric experimental techniques. The definition of new trends among the chemical and thermodynamic parameters of above is provided. References: 1 Salje, E. K. H. Annu. Rev. Mater. Res. 2012, 42, 265-283. 2 Salje, E. K. H.; Hayward, S. A.; Lee, W. T. Acta Cryst. A 2005, 61, 3-18. 3 Martucci, A.; Rodeghero, E.; Pasti, L.; Bosi, V.; Cruciani, G. Microporous Mesoporous Mater. 2015, 215, 175-182. 4 Wu, E. L.; Lawton, S. L.; Olson, D. H.; Rohrman Jr., A. C.; Kokotallo, G. T. J. Phys. Chem. 1979, 83, 2777-2781. 5 van Koningsveld, H.; Jansen, J. C.; van Bekkum, H. Zeolites 1987, 7, 564-568. 6 Ardit, M.; Martucci, A.; Cruciani, G. J. Phys. Chem. C 2015, 119, 7351-7359. 7 Ardit, M.; Martucci, A.; Pasti, L.; Rodeghero, E.; Beltrami, G.; Cruciani, G. J. Phys. Chem. C 2018, 122, 7249-7259. 8 Salje, E. Cambridge University Press: Cambridge, U.K., 1990. 9 Mentzen, B. F.; Letoffe, J.-M.; Claudy, P. Thermochim. Acta 1996, 288, 1-7

Structural relaxation in tetrahedrally coordinated Co2+ along the gahnite-Co-aluminate spinel solid solution

The structural relaxation around the Co2+ ion along the gahnite (ZnAl2O4)-Co-aluminate (CoAl2O4) join was investigated by a combined X-ray diffraction (XRD) and electronic absorption spectroscopy (EAS) approach. Monophasic spinel samples (Zn1–yCoyAl2O4 with y = 0, 0.25, 0.5, 0.75, and 1 apfu) were obtained through solid-state reaction (1300 °C with slow cooling). The cobalt incorporation induces a linear increase of the unit-cell parameter (a) accompanied by an increasing inversion parameter (up to 0.07) so that the Co2+ for Al3+ substitution in the octahedral site is, at a first approximation, the cause of the lattice expansion. However, a careful consideration of T-O distances highlights the role played by an enhanced covalence degree of Zn-O bonds. The optical spectra are characterized by the occurrence of electronic transitions of Co2+ in tetrahedral coordination affected by a strong spin-orbit coupling, causing a threefold splitting of spin-allowed bands. Further complications stem from mixing of quadruplet and doublet states (leading to a consistent intensity gain of spin-forbidden bands) and vibronic effects (producing intense sidebands). Crystal field strength goes from 4187 to 4131 cm–1 with increasing cobalt amount, while the Racah B parameter is in the 744–751 cm–1 range (C ∼3375 cm–1). To achieve a reliable estimation of the local Co-O distance, the tetrahedral distance evolution was recast to eliminate the effects of the inversion degree. By this way, a relaxation coefficient as low as ε = 0.47 was obtained, i.e., significantly smaller than literature data for other spinel systems. The gahnite-Co-aluminate join seems to be constrained by the strong preference of Zn2+ for the tetrahedral site in which its enhanced covalency can be exerted, limiting the cation exchange between tetrahedral and octahedral sites as well as the lattice flexibility