Shell and spatial structures: Between new developments and historical aspects

Advanced structural systems are more and more devoted to light, versatile, eco-sustainable structures. This goal can be achieved through the use of new materials and new approaches for structural optimization, form finding, design, and validation. Shell and spatial structures are representative of some of the most efficient structural systems in which the optimized use of materials is combined with effective structural forms and shapes. The ongoing development of analysis methods, design approaches and construction techniques of shell and spatial structures has resulted in an increasing interest from engineers, architects, and builders. This Special Issue is devoted to papers coming from a call principally addressed to the participants of the 1st Italian Workshop on Shell and Spatial Structures (https://sites.google.com/view/iwss2020/home) held online the last June 2020 after the lockdown restriction due to the Covid-19 pandemic (Figure 1). The experience of the first IWSS (IWSS2020) was particularly innovative. It brought together the interests of the Italian and the international community devoted to the study and applications of shell and spatial structures. The IWSS received two significant endorsements, from the IASS (www.iassstructures.org) and from the SISCO (www. siscoscienzadellecostruzioni.org)

Shell and spatial structures: Between new developments and historical aspects

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Quantification of the Lewis Basicities and Nucleophilicities of 1,3,5-Tris(dialkylamino)benzenes

AbstractEquilibrium constants for the formation of Wheland complexes from 1,3,5‐tris(dialkylamino)benzenes and benzhydrylium ions (Ar2CH+) have been determined photometrically in dichloromethane solution at 20 °C. The Lewis basicity of the ring carbons increases in the series trimorpholinobenzene<tripiperidinobenzene<tripyrrolidinobenzene. Wheland complexes, which are formed with equilibrium constants 102<K/M−1<106 in the reactions of triaminobenzenes with carbenium ions, show temperature‐dependent dynamic 1H NMR spectra, due to rapid reverse reactions and recombination at different positions of the triaminobenzenes. Since the rates of the formation of the Wheland complexes are too high to be measured directly, they were calculated as the product of photometrically determined equilibrium constants and the rate constants for the reverse reactions, which were derived from the dynamic 1H NMR spectra. The experimentally determined equilibrium and rate constants were in good agreement with the results of DFT calculations using the SMD solvent model. The calculations show that in all cases the Wheland complexes are thermodynamically more stable than the ammonium ions formed by attack of the benzhydrylium ions at the amino group of the title compounds, which explains the exclusive formation of Wheland complexes in thermodynamically controlled reactions. With nucleophilicity parameters in the range 10<N<15 the triaminobenzenes have comparable nucleophilic reactivities as enamines, silyl ketene acetals as well as stabilized phosphonium and sulfonium ylides

Safe use of human anatomical preparations in frontal and interactive teaching

In the institute of Human Anatomy of Pavia, the use of cadaver dissection is not economically feasible. In order to improve students’ preparation related to topography of the central nervous system, we decided to use formalin-fixed brains and cranial sections belonging to the collection of cadaveric specimens. These specimens, preserved in formalin, however cannot be manipulated as such by the students because formalin can cause headaches, burning sensation in the throat, difficult breathing and can trigger or aggravate asthma symptoms [1, 2]. Furthermore, formalin is known to be a human carcinogen [3]. In order to minimize toxic effects, whole brains were extensively washed in running water and then sliced according to different reference planes using a “home-made” device enabling cuts according to parallel planes. Finally, the resulting sections were inserted into transparent plastic envelopes, immerged in a solution composed by 0.5% agar and 1% sodium azide as preservative. Medical students can now use these human brain sections to test their own ability to recognize nervous system structures. This strategy optimize specimen’s choice and focalize student’s attention on peculiar, selected human samples in full compliance with current security laws

Synthesis of thia-Michael-Type Adducts between Naphthoquinones and N-Acetyl-L-Cysteine and Their Biological Activity

A series of naphthoquinones, namely, 1,4-naphthoquinone, menadione, plumbagin, juglone, naphthazarin, and lawsone, were reacted with N-acetyl-L-cysteine, and except for lawsone, which did not react, the related adducts were obtained. After the tuning of the solvent and reaction conditions, the reaction products were isolated as almost pure from the complex reaction mixture via simple filtration and were fully characterized. Therefore, the aim of this work was to evaluate whether the antitumor activity of new compounds of 1,4-naphthoquinone derivatives leads to an increase in ROS in tumor cell lines of cervical carcinoma (HeLa), neuroblastoma (SH-SY5Y), and osteosarcoma (SaOS2, U2OS) and in normal dermal fibroblast (HDFa). The MTT assay was used to assay cell viability, the DCF-DA fluorescent probe to evaluate ROS induction, and cell-cycle analysis to measure the antiproliferative effect. Compounds 8, 9, and 12 showed a certain degree of cytotoxicity towards all the malignant cell lines tested, while compound 11 showed biological activity at higher IC50 values. Compounds 8 and 11 induced increases in ROS generation after 1 h of exposure, while after 48 h of treatment, only 8 induced an increase in ROS formation in HeLa cells. Cell-cycle analysis showed that compound 8 caused an increase in the number of G0/G1-phase cells in the HeLa experiment, while for the U2OS and SH-SY5Y cell lines, it led to an accumulation of S-phase cells. Therefore, these novel 1,4-naphthoquinone derivatives may be useful as antitumoral agents in the treatment of different cancers

Comparative spectroscopic and electrochemical study of N-1 or N-2-alkylated 4-nitro and 7-nitroindazoles

Abstract Our research groups are by long time involved in the study of the reactivity and the pharmacological activity of nitrogen-containing heterocyclic compounds: in this line we have now examined the behaviour of some substituted 4- and 7-nitroindazoles. Considering the fact that nitroreduction processes are often essential steps for the biological activity of nitro compounds and remembering that some nitroindazoles show interesting biological activities, we have collected nuclear magnetic resonance, electron spin resonance, and cyclic voltammetry data and carried out density functional theory computations on the above compounds thus obtaining an accurate picture of electronic distribution and reduction processes of the examined substrates as a function of their chemical structure. Looking also to our previous results obtained examining the behaviour of 5- and 6-nitroindazoles, we have confirmed the different general behaviour of 1- and 2-alkyl substituted nitroindazoles strictly related to the known different electronic distribution in these two classes of compounds. Interestingly, cyclic voltammetry data have confirmed the ability of N-1 H nitroindazoles to give rise to the formation of dimers, already observed by us studying 5- and 6-nitroindazoles

Synthesis of Novel Tryptamine Derivatives and Their Biological Activity as Antitumor Agents

We synthesized five novel tryptamine derivatives characterized by the presence of an azelayl chain or of a 1,1,1-trichloroethyl group, in turn connected to another heterocyclic scaffold. The combination of tryptamin-, 1,1,1-trichloroethyl- and 2-aminopyrimidinyl- moieties produced compound 9 identified as the most active compound in hematological cancer cell lines (IC50 = 0.57–65.32 M). Moreover, keeping constant the presence of the tryptaminic scaffold and binding it to the azelayl moiety, the compounds maintain biological activity. Compound 13 is still active against hematological cancer cell lines and shows a selective effect only on HT29 cells (IC50 = 0.006 M) among solid tumor models. Compound 14 loses activity on all leukemic lines, while showing a high level of toxicity on all solid tumor lines tested (IC50 0.0015–0.469 M)

Evaluation of the effects of a dynamic culture on osteogenic differentiation of oral-periosteal cells grown on PLGA sponges

Oral-periosteum derived stem cells represent an innovative cell source for bone tissue engineering applications in terms of accessibility and self-commitment towards osteogenic lineage [1]. In this scenario, biomaterials play a pivotal role in tissue engineering in supporting stem cells growth and regeneration of tissue defects [2]. Among these biomaterials, Fisiograft®, a synthetic co-polymer composed of polylactic and polyglycholic acids produced by Ghimas (Bologna, Italy), is highly biocom- patible and completely absorbed within 4-6 months. In particular, Fisiograft® sponges are normally used in dental applications to fix completely periodontal defects without damage Schneider’s membrane. We evaluated the osteogenic potential of Fisiograft® sponges on oral-periosteal cells derived from patients undergoing dental extractions. For this purpose, we created a dynamic culture based on a rotating apparatus in which we seeded periosteal cells with Fisiograft® sponges for 7, 14 and 21 days without adding osteogenic supplement in the medium. Osteoblast differen- tiation of cells was evaluated by Alizarin Red S staining and by qRT-PCR on genes involved in bone development. Results show that Fisograft® sponges promote greater osteogenic differentiation of cells in the dynamic culture with respect to standard condition already at 14 days, as demonstrated by Alizarin Red staining. BMP-2 and Osteoprotegerin genes are highly expressed by cells grown on Fisiograft® sponges in dynamic culture at 14 days with respect to plastic culture. Taken together, these results confirm the osteogenic potential of Fisiograft® sponges in accelerating the dif- ferentiation of cells to an osteoblast phenotype (already to 14 days of culture) without any osteogenic induction. The combination of this PLGA biomaterial and oral-peri- osteal cells could represent a promising bio-complex in maxillo-facial tissue repair

New bioelectrical impedance vector references and phase angle centile curves in 4,367 adults: The need for an urgent update after 30 years

Background &amp; aims: The bioelectrical impedance vector analysis (BIVA) represents a qualitative analysis of body composition. The vector, defined by resistance (R) and reactance (Xc) standardized by stature, can be evaluated compared to the 50%,75%, and 95% tolerance ellipses representative of the reference populations. The tolerance ellipses for healthy adults have been provided in 1995 and were developed by mixing underage, adult, and elderly subjects, possibly misrepresenting the actual adult population. The current multicentric, cross-sectional study aimed to provide new tolerance ellipses specific for the general adult population and as a secondary aim to present centile curves for the bioelectrical phase angle. Methods: R, Xc, and phase angle were measured in 2137 and 2230 males and females using phase-sensitive foot-to-hand analyzers at 50&nbsp;kHz. A minimum of 35 subjects were included for each sex and age category from 18 to 65 years. Results: The new mean vectors showed a leftward shift on the R-Xc graph with respect to the former reference values (males: F&nbsp;=&nbsp;75.3; p&nbsp;&lt;&nbsp;0.001; females: F&nbsp;=&nbsp;36.6, p&nbsp;&lt;&nbsp;0.001). The results provided new 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97th percentile curves for phase angle, identifying time point phases of decrement (males:&nbsp;-0.03° per year at 33.0-51.0 years and&nbsp;-0.05° per year after 51 years; females:&nbsp;-0.03° per year from 37.2 to 57.9 years). Conclusions: Compared to the original references, the new data are characterized by a different distribution within the R-Xc graph with a higher phase angle. Thirty years after the BIVA invention, the current study presents new tolerance ellipses and phase angle reference values for the adult population

Synthesis of Novel Structural Hybrids between Aza-Heterocycles and Azelaic Acid Moiety with a Specific Activity on Osteosarcoma Cells

Nine compounds bearing pyridinyl (or piperidinyl, benzimidazolyl, benzotriazolyl) groups bound to an azelayl moiety through an amide bond were synthesized. The structural analogy with some histone deacetylase inhibitors inspired their syntheses, seeking new selective histone deacetylase inhibitors (HDACi). The azelayl moiety recalls part of 9-hydroxystearic acid, a cellular lipid showing antiproliferative activity toward cancer cells with HDAC as a molecular target. Azelayl derivatives bound to a benzothiazolyl moiety further proved to be active as HDACi. The novel compounds were tested on a panel of both normal and tumor cell lines. Non-specific induction of cytotoxicity was observed in the normal cell line, while three of them induced a biological effect only on the osteosarcoma (U2OS) cell line. One of them induced a change in nuclear shape and size. Cell-cycle alterations are associated with post-transcriptional modification of both H2/H3 and H4 histones. In line with recent studies, revealing unexpected HDAC7 function in osteoclasts, molecular docking studies on the active molecules predicted their proneness to interact with HDAC7. By reducing side effects associated with the action of the first-generation inhibitors, the herein reported compounds, thus, sound promising as selective HDACi