A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

Microstructured honeycomb materials may exhibit exotic, extreme and tailorable mechanical properties, suited for innovative technological applications in a variety of modern engineering fields. The paper is focused on analysing the directional auxeticity of tetrachiral materials, through analytical, numerical and experimental methods. Theoretical predictions about the global elastic properties have been successfully validated by performing tensile laboratory tests on tetrachiral samples, realized with high precision 3D printing technologies. Inspired by the kinematic behaviour of the tetrachiral material, a newly-design bi-layered topology, referred to as bi-tetrachiral material, has been theoretically conceived and mechanically modelled. The novel topology virtuously exploits the mutual collaboration between two tetrachiral layers with opposite chiralities. The bi-tetrachiral material has been verified to outperform the tetrachiral material in terms of global Young modulus and, as major achievement, to exhibit a remarkable auxetic behaviour. Specifically, experimental results, confirmed by parametric analytical and computational analyses, have highlighted the effective possibility to attain strongly negative Poisson ratios, identified as a peculiar global elastic property of the novel bi-layered topology

Short and middle term effects of hypocaloric low carbohydrate diet vs hypocaloric Mediterranean diet on endothelial function in obese subjects

Adequate nutritional treatment is required to address the problem of increasing prevalence of obesity in Western countries. The Mediterranean diet style is now acknowledged to have large scientific evidences in terms of cardiovascular prevention. However, many popular diets are diffusing also as self-prescribed treatments. Among those, the efficacy of low-carbohydrate diets (also known as Atkins’ diet in its most popular variety) has been addressed by some investigations. It is generally concluded that the low-carbohydrate diet is able to induce a greater weight loss, at least in the middle term, and a better serum lipid profile than the conventional diet. In this longitudinal, randomised, open study we compared the effects on endothelial function of a hypocaloric low-carbohydrate diet (according to the Atkins’ diet; AD) versus a similarly hypocaloric Mediterranean diet (MD). Overweight-obese (range of BMI: 27-34.9 Kg/m2; range of age: 30-50 years) otherwise healthy, normal glucose tolerant women were enrolled and randomly assigned to one of the two dietary treatments until reaching the final number of 10 women for each group of treatment. So, twenty-five women were enrolled and five of them (3 in the MD group and 2 in the AD group) were subsequently excluded from the study due to intercurrent diseases (1 subject) or declaration of inadequate compliance (2 subjects) or f voluntary drop out (2 subjects). Measurements were performed before (T0), 5-7 days (T5) and 2 months (T60) after starting the diet treatment. Endothelial function was investigated at each time of the study by measuring the brachial artery flow-mediated dilation (FMD). Serum concentrations of insulin, adiponectin, interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and 8-iso-prostaglandin (8-iso-PG) F2α were also assessed at each time of the study. Urinary ketone bodies were observed at T5 only in AD group. Briefly, body weight was not significantly decreased at T5 in both groups; as expected, a higher body weight reduction was observed at T60 in AD group (change in body weight T60 – T0, mean ± sem, MD -4.9 ± 0.6 Kg vs AD -7.6 ± 0.8 Kg, p= 0.014). The FMD was significantly reduced at T5 in the AD group and increased at T60 until reaching the T0 values (T0: 12.2 ± 2.9; T5: 5.2 ± 0.8; T60: 11.0 ± 1.2 %; p< 0.05 T5 vs T0 and T60). On the contrary, the FMD increased significantly at T5 in the MD group and decreased until reaching values comparable to those of T0 at T60 (T0: 10.3 ± 2.3; T5: 14.5 ± 2.8; T60: 10.6 ± 1.9 %; p< 0.05 T5 vs T0 and T60). This trend of FMD change was observed in each subject. Insulin concentrations and HOMA-I decreased significantly at T5 and at T60 in both groups. Adiponectin and TNF-α concentrations remained unchanged in both groups throughout the study. Both IL-6 and 8-iso-PGF2α increased significantly at T5 in the AD group and decreased at T60 to values comparable to T0 (IL-6: T0 57.5 ± 9.0, T5 78.1 ± 10.9, T60 56.6 ± 6.8 pg/ml; T5 vs T0 p< 0,005, T5 vs T60 p< 0,02; 8-iso-PGF2α: T0 171.5 ± 30.6, T5 222.6 ± 35.1, T60 178.7 ± 25.8 pg/ml; T5 vs T0 p< 0,005, T5 vs T60 p< 0,02); no significant change was observed in the MD group. This study suggests that the hypocaloric low-carbohydrate diet induces a significant endothelial dysfunction in the short term (5-7 days) that is reverted in the middle term (2 months) as suggested by both the brachial artery FMD and serum markers of inflammation (IL-6) and oxidative stress (8-iso-PGF2α). On the contrary, the hypocaloric Mediterranean diet is able to improve the endothelial function at least in the short term. These effects are independent of body weight loss. Therefore, this study points out also the potential disadvantages of low-carbohydrate diets when prescribed (or self-prescribed) especially in subjects at high cardiovascular risk

Aquafeed production from fermented fish waste and lemon peel

In order to obtain a high-protein-content supplement for aquaculture feeds, rich in healthy microorganisms, in this study, Saccharomyces cerevisiae American Type Culture Collection (ATCC) 4126 and Lactobacillus reuteri ATCC 53608 strains were used as starters for fermenting fish waste supplemented with lemon peel as a prebiotic source and filler. Fermentation tests were carried out for 120 h until no further growth of the selected microorganisms was observed and the pH value became stable. All the samples were tested for proteins, crude lipids, and ash determination, and submitted for fatty acid analysis. Moreover, microbiological analyses for coliform bacteria identification were carried out. At the end of the fermentation period, the substrate reached a concentration in protein and in crude lipids of 48.55 ± 1.15% and 15.25 ± 0.80%, respectively, representing adequate levels for the resulting aquafeed, whereas the ash percentage was 0.66 ± 0.03. The main fatty acids detected were palmitic, oleic, and linoleic acids. Saturated fatty acids concentration was not affected by the fermentation process, whereas monounsaturated and polyunsaturated ones showed an opposite trend, increasing and decreasing, respectively, during the process. Coliform bacteria were not detected in the media at the end of the fermentation, whereas the amount of S. cerevisiae and L. reuteri were around 1011 and 1012 cells per g, respectively

Polypoidal choroidal vasculopathy in pachychoroid: combined treatment with photodynamic therapy and aflibercept

Introduction: To evaluate the effects of combined therapy using intravitreal Aflibercept (IVA) and photodynamic therapy (PDT) on polypoidal choroidal vasculopathy related to pachychoroid disease (PPCV). Methods: Patients with PPCV were treated with PDT combined with 3 IVA injections on a monthly basis, followed by pro re nata criteria. The 12-month follow-up consisted of multiple revaluations of visual acuity and SS-OCT parameters of clinical activity. Results: Nineteen eyes were included in the study; mean age was 65.5&nbsp;years. Visual acuity improved after 12&nbsp;months (0.35 ± 0.25 to 0.2 ± 0.20 logMAR, p = 0.005). Percentage of eyes with intraretinal and subretinal fluid reduced from baseline to the 12-month follow-up (from 52.6 to 10.5%, p = 0.12, and from 89.5 to 5.3% p = 0.0009, respectively). Central retinal and mean macular thicknesses reduced (258 ± 39.6 to 204.8 ± 38.8&nbsp;μm p = 0.04 and 293.8 ± 32.1 to 248.1 ± 29.6&nbsp;μm p = 0.017, respectively). Central choroidal and mean choroidal thicknesses also displayed a reduction (328.6 ± 54.9 to 289.8 ± 44.6&nbsp;μm p = 0.001 and 314.5 ± 55.3 to 287.9 ± 47.6&nbsp;μm p = 0.015, respectively). The mean number of injections was 4.6/year. Conclusion: The results support the use of a combined therapy with Aflibercept and PDT in PPCV. This treatment would act in synergy, with anti-VEGF controlling exudation and PDT closing the aneurysmal vessel and reducing choroidal congestion

Screening and Management of Coronary Artery Disease in Kidney Transplant Candidates

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with chronic kidney disease (CKD), especially in end-stage renal disease (ESRD) patients and during the first year after transplantation. For these reasons, and due to the shortage of organs available for transplant, it is of utmost importance to identify patients with a good life expectancy after transplant and minimize the transplant peri-operative risk. Various conditions, such as severe pulmonary diseases, recent myocardial infarction or stroke, and severe aorto-iliac atherosclerosis, need to be ruled out before adding a patient to the transplant waiting list. The effectiveness of systematic coronary artery disease (CAD) treatment before kidney transplant is still debated, and there is no universal screening protocol, not to mention that a nontailored screening could lead to unnecessary invasive procedures and delay or exclude some patients from transplantation. Despite the different clinical guidelines on CAD screening in kidney transplant candidates that exist, up to today, there is no worldwide universal protocol. This review summarizes the key points of cardiovascular risk assessment in renal transplant candidates and faces the role of noninvasive cardiovascular imaging tools and the impact of coronary revascularization versus best medical therapy before kidney transplant on a patient’s cardiovascular outcome

Relationship of choroidal thickness with pulsatile hemodynamics in essential hypertensive patients

Controversy exists about the association of choroidal thickness (CTh) with blood pressure (BP) values. There is some evidence suggesting that central hemodynamics changes are associated with microvascular disease. Our study was aimed to assess the relationships between CTh and clinic and 24-h BP and between CTh and estimated 24-h aortic pulse pressure (aPP), 24-h aortic systolic BP (aSBP), and 24-h aortic augmentation index (aAIx) in a group of hypertensive patients. We enrolled 158 hypertensive subjects (mean age 48&nbsp;±&nbsp;13&nbsp;years) all of which underwent evaluation of the choroidal district by Swept-Source optical coherence tomography (SS-OCT) and 24-h BP monitoring, in order to measure peripheral BP and to estimate central hemodynamic parameters. Inverse significant correlations of clinic PP, 24-h aPP, 24-h aSBP, and 24-h aAIx with thicknesses of central ring, inner ring, and outer ring of the choroid and its overall average were found. The strongest of these correlations was that relating 24-h aPP with overall average choroidal thickness (r&nbsp;=&nbsp;−.531; P&nbsp;&lt;.001). When we divided the study population in subjects with 24-h aPP above and below the median value (35&nbsp;mm Hg), CTh were thinner in subjects with higher values of 24-aPP as compared to those with lower ones, even after adjustment for age, and other potential confounders. The relationships of CTh with 24-h aPP remained significant also taking into account the effects of various covariates in linear multiple regression analyses. Our findings support the concept of a cross-talk between macro- and microcirculation

Metered Cryospray™: a novel uniform, controlled, and consistent in vivo application of liquid nitrogen cryogenic spray

Typically, wood-based composite materials have been developed through empirical studies. In these products, the constituent wood elements have broad spectrums regarding species, size, and anatomical orientation relative to their own dimensions. To define special strength and stiffness properties during a long-term study, two types of corrugated wood composite panels were developed for possible structural utilization. The constitutional elements of the newly developed products included Appalachian hardwood veneer residues (side clippings) and/or rejected low quality, sliced veneer sheets. The proposed primary usage of these veneer-based panels is in applications where the edgewise loading may cause buckling (e.g., web elements of I-joists, shear-wall and composite beam core materials). This paper describes the development of flat and corrugated panels, including furnish preparations and laboratory-scale manufacturing processes as well as the determination of key mechanical properties. According to the results in parallel to grain direction bending, tension and compression strengths exceeded other structural panels’ similar characteristics, while the rigidities were comparable. Based on the research findings, sliced veneer clipping waste can be transformed into structural panels or used as reinforcement elements in beams and sandwich-type products