Initiation of Failure for Masonry Subject to In-Plane Loads through Micromechanics

A micromechanical procedure is used in order to evaluate the initiation of damage and failure of masonry with in-plane loads. Masonry material is viewed as a composite with periodic microstructure and, therefore, a unit cell with suitable boundary conditions is assumed as a representative volume element of the masonry. The finite element method is used to determine the average stress on the unit cell corresponding to a given average strain prescribed on the unit cell. Finally, critical curves representing the initiation of damage and failure in both clay brick masonry and adobe masonry are provided

A Numerical Method for a Nonlocal Form of Richards' Equation Based on Peridynamic Theory

Forecasting water content dynamics in heterogeneous porous media has significant interest in hydrological applications; in particular, the treatment of infiltration when in presence of cracks and fractures can be accomplished resorting to peridynamic theory, which allows a proper modeling of non localities in space. In this framework, we make use of Chebyshev transform on the diffusive component of the equation and then we integrate forward in time using an explicit method. We prove that the proposed spectral numerical scheme provides a solution converging to the unique solution in some appropriate Sobolev space. We finally exemplify on several different soils, also considering a sink term representing the root water uptake

Learning curve and global benchmark values of laparoscopic sleeve gastrectomy: results of first 100 cases of a newly trained surgeon in an Italian center of excellence

To evaluate whether the learning curve for sleeve gastrectomy could be completed after 50 cases. First 100 patients undergoing LSG under a newly trained laparoscopic surgeon were included in this study and divided into two groups of 50 consecutive patients each. Perioperative outcomes were compared to recently introduced global benchmarks. Short-term weight loss was calculated as Total Weight Loss Percent (%TWL) and complications were classified in accordance with the Clavien–Dindo classification. CUSUM analysis was performed for operative time and hospital stay. Mean preoperative age and BMI were 41.8 ± 10.3 years and 42.9 ± 5.4 kg/m2, respectively. Demographics and rate of patients with previous surgery were comparable preoperatively in the two groups. Mean operative time was 92.1 ± 19.3 min and hospital stay was 3.4 ± 0.6 days as per our standard protocol of discharge. Uneventful postoperative course was recorded in 93% of patients and only one case of staple line leak was registered in the first 50 cases (group 1). No statistical difference in BMI and %TWL was found between the two groups at any time of follow-up. Comparison between two groups showed a significant reduction in hospital stay and operative time after the first 50 LSGs (p < 0.05). LSG can be performed by newly trained surgeons proctored by senior tutors. At least 50 cases are needed to meet global benchmark cut-offs and few more cases may be required to reach the plateau of the learning curve

Ten-Year Results of Laparoscopic Sleeve Gastrectomy: Retrospective Matched Comparison with Laparoscopic Adjustable Gastric Banding—Is There a Significant Difference in Long Term?

Background: The laparoscopic sleeve gastrectomy (LSG) is the most common bariatric procedure performed worldwide while the laparoscopic adjustable gastric banding (LAGB) has been almost abandoned. Aim of this study was to retrospectively assess 10-year outcomes of LSG through a matched comparison with LAGB. Materials and Methods: Retrospective search of prospectively maintained database of our university was carried out to find all patients that underwent LSG before December 2010. Each subject with LSG was matched one-to-one with a patient that had undergone LAGB in the same period with correspondent preoperative age, BMI, and sex. Results: A total of 76 patients underwent LSG before 2010 and were all included in this study; a matched group of 76 out of 178 LAGB patients with 10-year follow-up was retrieved from our database. Comparison between the two groups showed better outcomes after LSG at 1 and 5 years but weight loss was comparable with the LAGB group at 10 years (%TWL 22.2 ± 13 vs 21.2 ± 16.1; p = 0.89). No significant difference was found in conversion/removal rate (15.8% vs 18.4%; p = 0.67). Conclusion: LSG is an effective stand-alone bariatric procedure with better outcomes than LAGB in medium term, but results are comparable at 10 years. Subjects undergoing LSG should be informed that conversion to RYGB or OAGB may be necessary to achieve further weight loss or to treat reflux. Graphical abstract: [Figure not available: see fulltext.

Impact of COVID-19 Lockdown on Short-term Weight Loss in a Single Italian Institution

Italy was the first European country to have a major outbreak of COVID-19. Bariatric procedures were stopped and telemedicine had to be implemented. A large percentage of patients struggled to follow postoperative diet and to start physical activity due to social restrictions. We have compared short-term outcomes of patients who had bariatric procedures prior to lockdown with subjects that had undergone obesity surgery in the same period of the previous year at our institution. A total number of 63 patients were included in this study. Weight loss at 1, 3 and 6 postoperative months in the 2019 group was significantly higher at any point of follow-up when compared to 2020. Social limitations and nonattendance of clinical appointments may have compromised early results. Graphical Abstract: [Figure not available: see fulltext.]

Core charge distribution and self assembly of columnar phases: the case of triphenylenes and azatriphenylenes

<p>Abstract</p> <p>Background</p> <p>The relation betweeen the structure of discotic molecules and columnar properties, a crucial point for the realization of new advanced materials, is still largely unknown. A paradigmatic case is that hexa-alkyl-thio substituted triphenylenes present mesogenic behavior while the corresponding azatriphenylenes, similar in shape and chemical structure, but with a different core charge distribution, do not form any liquid crystalline mesophase. This study is aimed at investigating, with the help of computer simulations techniques, the effects on phase behaviour of changes of the charge distribution in the discotic core.</p> <p>Results</p> <p>We described the shape and the pair, dispersive and electrostatic, interactions of hexa alkyl triphenylenes by uniaxial Gay-Berne discs with embedded point charges. Gay-Berne parameters were deduced by fitting the dispersive energies obtained from an atomistic molecular dynamics simulation of a small sample of hexa-octyl-thio triphenylene molecules in columnar phase, while a genetic algorithm was used to get a minimal set of point charges that properly reproduces the ab anitio electrostatic potential. We performed Monte Carlo simulations of three molecular models: the pure Gay-Berne disc, used as a reference, the Gay-Berne disc with hexa-thio triphenylene point charges, the Gay-Berne disc with hexa-thio azatriphenylene point charges. The phase diagram of the pure model evidences a rich polymorphism, with isotropic, columnar and crystalline phases at low pressure, and the appearance of nematic phase at higher pressure.</p> <p>Conclusion</p> <p>We found that the intermolecular electrostatic potential among the cores is fundamental in sta-bilizing/destabilizing columnar phases; in particular the triphenylene charge distribution stabilizes the columnar structure, while the azatriphenylene distribution suppresses its formation in favor of the nematic phase. We believe the present model could be successfully employed as the basis for coarse-grained level simulations of a wider class of triphenylene derivatives.</p

Endocrine-disrupting chemicals and their effects during female puberty: A review of current evidence

Puberty is the process of physical changes between childhood and adulthood during which adolescents reach sexual maturity and become capable of reproduction. It is considered one of the main temporal windows of susceptibility for the influence of the endocrine-disrupting chemicals (EDCs). EDCs may act as single chemical agents or as chemical mixtures; they can be pubertal influencers, accelerating and anticipating the processing of maturation of secondary sexual characteristics. Moreover, recent studies have started to point out how exposure to EDCs during puberty may predispose to breast cancer later in life. In fact, the estrogen-mimicking endocrine disruptors (EEDs) may influence breast tissue development during puberty in two main ways: the first is the action on the proliferation of the breast stromal cells, the second concerns epigenetic mechanisms. The aim of this mini-review was to better highlight what is new and what is not completely known regarding the role of EDCs during puberty

Morbid obesity and thyroid cancer rate. A review of literature

In the past three decades, several recent studies have analyzed the alarming increase of obesity worldwide, and it has been well established that the risk of many types of malignancies is increased in obese individuals; in the same period, thyroid cancer has become the fastest growing cancer of all malignancies. We investigated the current literature to underline the presence of a connection between excess body weight or Body Mass Index (BMI) and risk of thyroid cancer. Previous studies stated that the contraposition between adipocytes and adipose-resident immune cells enhances immune cell production of multiple pro-inflammatory factors with subsequent induction of hyperlipidemia and vascular injury; these factors are all associated with oxidative stress and cancer development and/or progression. Moreover, recent studies made clear the mitogenic and tumorigenic action of insulin, carried out through the stimulation of mitogen-activated protein kinase (MAPK) and phosphoinositide-3 kinase/AKT (PI3K/AKT) pathways, which is correlated to the hyperinsulinemia and hyperglycemia found in obese population. Our findings suggest that obesity and excess body weight are related to an increased risk of thyroid cancer and that the mechanisms that combine overweight with this cancer should be searched for in the adipokine pathways and chronic inflammation onset

Alterations in biomarkers of cardiovascular disease (CVD) in active acromegaly

Objectives: In acromegalic patients, cardiovascular and metabolic comorbidities contribute to enhance mortality. Available data on the lipoprotein profile of these patients are controversial. Our aim was to characterize the lipoprotein profile and emergent biomarkers of cardiovascular disease in active acromegalic patients in comparison with sex- and age-matched healthy controls. Patients: Eighteen patients with active acromegaly and 18 controls were studied. Measurements: Glucose levels, hormonal status, lipoprotein profile and C reactive protein (CRP) were evaluated by standardized methods. Cholesteryl ester transfer protein (CETP) and lipoprotein-associated phospholipase A2 (Lp-PLA2) were measured by radiometric techniques, endothelin-1 and vascular cell adhesion molecule (VCAM)-1 by enzyme-linked immunosorbent assay, and leucocytes CD18, CD49d and CD54 by flow cytometry. Results: After adjusting for body mass index (BMI), acromegalic patients presented a more atherogenic lipoprotein profile, consisting of higher levels of triglycerides and apolipoprotein B and alterations in the ratios which estimate insulin resistance and atherogenic risk. CETP activity was significantly increased in acromegalic patients as compared to controls (168 ± 17 vs. 141 ± 30% per ml h, respectively; P < 0.05). Endothelin-1 levels evidenced an increase in the patients' group (0.9 ± 0.2 vs. 0.7 ± 0.2 ng/l, respectively; P < 0.01) and showed positive and significant correlations with GH, IGF-1 and IGFBP-3 (r = 0.45, 0.42 and 0.44, respectively; P < 0.01 for all of them; with BMI as a fixed variable). Lymphocytes from acromegalic patients showed increased CD49d content (282 ± 59 vs. 246 ± 48 arbitrary units, respectively; P < 0.05). Conclusions: Taken together, the alterations described seem to contribute to constituting a state of higher propensity for the development of atherosclerotic cardiovascular disease, which adds to the presence of specific cardiomyopathy.Fil: Boero, Laura Estela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Manavela, M.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Gomez Rosso, Leonardo Adrián. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Insua, C.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Berardi, V.. No especifíca;Fil: Fornari, M.C.. No especifíca;Fil: Brites, Fernando Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

The secretory senescence in otorhinolaryngology: Principles of treatment

Atrophy or hypofunction of the salivary gland because of aging, radiotherapy or disease causes hyposalivation and impairs the quality of life of patients by compromising mastication, swallowing and speech and by leading to a loss of taste. Moreover, hyposalivation exacerbates dental caries and induces periodontal disease, and oral candidiasis. Currently, no satisfactory therapies have been established to solve salivary hypofunction. Current treatment options for atrophy or hypofunction of the salivary glands in clinical practice are only symptomatic and include saliva substitutes and parasympathetic agonists, such as pilocarpine, to stimulate salivary flow. However, parasympathomimetics have systemic side effects, so different treatment options are necessary, and research has recently focused on this. The main strategies that have been proposed to restore salivary gland atrophy and hypofunction are gene therapy by gene activation/silencing during stem cell differentiation and by the use of viral vectors, such as adenoviruses; cell-based therapy with salivary gland cells, stem cells and non-salivary gland and/ or non-epithelial cells to regenerate damaged salivary gland cells; replacement with tissue bioengineering in which organoids from pluripotent stem cells are used in the development of organ replacement regenerative therapy. Remarkable progression in this research field has been made in the last decade, but a definitive therapy for salivary gland hypofunction has not been developed due to intrinsic challenges that come with each approach. However, with research efforts in the future, a range of precision medicine therapies may become available individualized to each patient