Anterior gastric wall anastomosis may lead to lower rate of delayed gastric emptying after minimally invasive Ivor Lewis esophagectomy: a retrospective cohort study.

INTRODUCTION: In minimally invasive esophagectomy, a circular stapled anastomosis is common, but no evidence exists investigating the role of the specific localization of the anastomosis. The aim of this study is to evaluate the impact of an esophagogastrostomy on the anterior or posterior wall of the gastric conduit on the postoperative outcomes. MATERIAL AND METHODS: All oncologic minimally invasive Ivor Lewis procedures, performed between 2017 and 2022, were included in this study. The cohort was divided in two groups: a) intrathoracic esophagogastrostomy on the anterior gastric wall of the conduit (ANT, n = 285, 65%) and b) on the posterior gastric wall (POST, n = 154, 35%). Clinicopathological parameters and short-term outcomes were compared between both groups by retrieving data from the prospective database. RESULTS: Overall, 439 patients were included, baseline characteristics were similar in both groups, there was a higher proportion of squamous cell carcinoma in ANT (22.8% vs. 16.2%, P = 0.043). A higher rate of robotic-assisted procedures was observed in ANT (71.2% vs. 49.4%). Anastomotic leakage rate was similar in both groups (ANT 10.4% vs. POST 9.8%, P = 0.851). Overall complication rate and Clavien-Dindo > 3 complication rates were higher in POST compared to ANT: 53.2% vs. 40% (P = 0.008) and 36.9% vs. 25.7% (P = 0.014), respectively. The rate of delayed gastric emptying (20.1% vs. 7.4%, P < 0.001) and nosocomial pneumonia (22.1% vs. 14.8%, P = 0.05) was significantly higher in POST. CONCLUSION: Patients undergoing minimally invasive Ivor Lewis esophagectomy with an intrathoracic circular stapled anastomosis may benefit from esophagogastrostomy on the anterior wall of the gastric conduit, in terms of lower rate of delayed gastric emptying.

Mosses on Geopolymers: Preliminary Durability Study and Chemical Characterization of Metakaolin-Based Geopolymers Filled with Wood Ash.

Burning wood is estimated to produce about 6-10% of ash. Despite the possibility of recycling wood ash (WA), approximately 70% of the wood ash generated is landfilled, causing costs as well as environmental pollution. This study aims to recycle WA in an alternative way by inserting it as filler in geopolymeric materials. Here, metakaolin, NaOH, sodium silicate, and WA are used to realize geopolymers. Geopolymers without and with 10, 20 and 30% of WA are synthesized and characterized after 7, 14, 28 and 56 days. The article's study methods are related to geopolymers' chemical, biological and mechanical properties. The geopolymers synthesized are compact and solid. The pH and conductivity tests and the integrity and weight loss tests have demonstrated the stability of materials. The FT-IR study and boiling water test have confirmed the successful geopolymerization in all samples. The antibacterial analysis, the moss growing test and the compressive strength test have given a first idea about the durability of the materials synthesized. Furthermore, the compressive strength test result has allowed the comparison from the literature of the specimens obtained with the Portland cement (PC). The results obtained bode well for the future of this material.

New Materials and Technologies for Durability and Conservation of Building Heritage.

The increase in concrete structures' durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings.

Fabrication of High-Performance CNT Reinforced Polymer Composite for Additive Manufacturing by Phase Inversion Technique.

Additive Manufacturing (AM) of polymer composites has enabled the fabrication of highly customized parts with notably mechanical properties, thermal and electrical conductivity compared to un-reinforced polymers. Employing the reinforcements was a key factor in improving the properties of polymers after being 3D printed. However, almost all the existing 3D printing methods could make the most of disparate fiber reinforcement techniques, the fused filament fabrication (FFF) method is reviewed in this study to better understand its flexibility to employ for the proposed novel method. Carbon nanotubes (CNTs) as a desirable reinforcement have a great potential to improve the mechanical, thermal, and electrical properties of 3D printed polymers. Several functionalization approaches for the preparation of CNT reinforced composites are discussed in this study. However, due to the non-uniform distribution and direction of reinforcements, the properties of the resulted specimen do not change as theoretically expected. Based on the phase inversion method, this paper proposes a novel technique to produce CNT-reinforced filaments to simultaneously increase the mechanical, thermal, and electrical properties. A homogeneous CNT dispersion in a dilute polymer solution is first obtained by sonication techniques. Then, the CNT/polymer filaments with the desired CNT content can be obtained by extracting the polymer's solvent. Furthermore, optimizing the filament draw ratio can result in a reasonable CNT orientation along the filament stretching direction.

Comparative Study of Phenomenological Residual Strength Models for Composite Materials Subjected to Fatigue: Predictions at Constant Amplitude (CA) Loading.

The most popular methods of characterizing a composite's fatigue properties and predicting its life are phenomenological, meaning the micro-mechanisms of composite structures under cyclic loading are not treated. In addition, in order to characterize the fatigue properties, only macro-parameters, namely strength and/or stiffness, are adopted. Residual strength models are mostly used in practice, given their strong relationship with safety and reliability. Indeed, since failure occurs when the strength degrades to the peak stress of fatigue loading, the remaining strength is used as a failure index. In this paper, based on a wide set of literature data, we summarize the capabilities of four models, namely Caprino's, D'Amore's, Sendekyj's, and Kassapoglou's models. The models are briefly described and then applied to the same data set, which is re-elaborated. The selected experimental data are recovered from a large experimental campaign carried out by the Federal Aviation Administration (FAA). Specimens of the same material were subjected to different loading in terms of peak stress, σmax, and stress ratio, R = σmin/σmax, ranging from pure tension (0 < R < 1) to prevalent tension (-1 < R < 0) to tension-compression (R = -1) to pure compression (1 < R < ∞). The data represent a formidable test bed to comparatively evaluate the models' capabilities and their predictive prerogatives. The models are also tested with respect to their ability to replicate the principal responses' feature of composite materials subjected to constant amplitude (CA) loadings. It is shown that Caprino's and D'Amore's models are equally capable of adequately fitting the experimental fatigue life data under given loading conditions and predicting the fatigue behavior at different loading ratios, R, with two fixed parameters. Sendekyj's model required different parameters' sets for each loading condition, and Kassapoglou's model was unable to fit the majority of fatigue life data. When compared on the basis of the residual strength data, only the recently developed D'Amore's model revealed its reliability.

Principal Features of Fatigue and Residual Strength of Composite Materials Subjected to Constant Amplitude (CA) Loading.

This paper summarizes the principal features of composites' responses when subjected to constant amplitude (CA) cyclic loadings. The stochastic nature of the responses; the absence of a detectable fatigue limit; the sudden drop of strength; the general validity of the strength-life equal-rank assumption (SLERA); and, ultimately, the residual strength-life equal-rank assumption (RSLERA) are discussed on the basis of the selected experimental data available in literature. The objective is defining a robust test in order to ascertain the reliability of the phenomenological models. A two-parameter phenomenological model accounting for the maximum cyclic stress, σmax, and the stress ratio, R = σmin/σmax, was used for guidance through the phenomenology of fatigue. It is concluded that the robustness of the models dealing with fatigue can be checked only when the characteristics of the composites' responses are described simultaneously with fixed parameters.

Constitutive law describing the phenomenology of subyield mechanically stimulated glasses.

The principal features of the volumetric as well as the viscoelastic response of mechanically stimulated glasses can be summarized as follows: (i) the time-aging time shift factors contract upon increasing the probe stress (i.e., the stress apparently modifies the volume recovery kinetics), (ii) the volume recovery baseline remains unaltered (i.e., the underlying structure of the stimulated glass remains unchanged). Here we present a series of numerically simulated results concerning the responses of glassy polycarbonate that simultaneously fulfill these apparent contradictions. The problem was tackled coupling a modified Kalroush, Aklonis, Hotchinson, Ramos equation with the constitutive law for linear viscoelasticity within the domain of the reduced time. It was argued that the relaxation times under isobaric conditions depend on the temperature, the dimensionless volume, and the isotropic components of the stress tensor. Simulations are obtained with a minimum of experimental ( PVT and linear viscoelastic) data inputs. Different loading protocols consisting of complex combinations and/or sequences of large and small mechanical stimuli were tested. Volumetric as well as viscoelastic behavior are systematically reported. A tentative explanation of the origin of the time-aging time contraction was finally proposed while some additional features concerning the volumetric response emerged.