Vulnerability and Structural Capacity Assessment of Historic Glass Facades under Bird-Strike

Bird-strike analysis is of particular relevance for aircraft engineering applications, where major wing or fuselage components may suffer for possible collision during flying stage and result in serious structural damage. To this aim, the Federal Aviation Regulations requires dedicated bird-strike resistance assessment tests and certifications. In building applications, glass is also largely used for vertical and horizontal load-bearing components. In such a kind of structural design context, major attention is given to wind pressure, seismic loads, impact due to crowd and human body (i.e., to prevent falling out), or even explosions, and rather null consideration is posed for bird-strike analysis, due to their expected limited impact forces and effects on glass. This paper investigates such a topic giving evidence of the dynamic response of an existing glass facade built in 60 s as a part of a museum in Italy. The vulnerability analysis is carried out with computationally efficient Finite Element (FE) numerical models of consolidated use for bird-strike, based also on preliminary mechanical characterization from in-field geometrical inspection and Operational Modal Analysis (OMA) experiments. Local and global dynamic effects due to localized bird-strike on the examined glass facade are discussed based on parametric numerical analysis from Coupled Eulerian Lagrangian (CEL) method

Simplified Procedure for Capacity Check of Historic Monolithic Glass Windows under Soft-Body Collision/Bird-Strike

Differing from present structural design procedures, most of the existing glass windows and even historic components in traditional/old buildings are not specifically designed to resist possible accidental loads. Rather thin monolithic ordinary annealed glass panels can be found in vertical non-structural envelopes, where they are often arranged to cover large surfaces. As such, an accidental glass fracture could originate even from rather common and moderate impact events and result in severe risk for people, due to propagation of dangerous shards from these vulnerable and fragile building components. To assess potential risks and support possible mitigation strategies, the present study is focused on the bird-strike analysis of existing/historic linearly restrained non-structural glass windows, based on a parametric Smoothed-Particle Hydrodynamics (SPH)–Finite Element (FE) model. Starting from a 1 m–wide and 1.5 m–high configuration, the attention is first given to various influencing parameters, such as impactor features (mass, 0.35–1.81 kg; impact speed, 0–40 m/s; and, thus, impact energy) and the target window (glass thickness, 4–6 mm; impact point; and, thus, glass stiffness). Local and global effects due to parametric localized bird-strikes are discussed based on non-linear dynamic numerical analyses and in terms of expected deflections, tensile stress peaks, and damage extension/severity (i.e., D1 to D3 damage levels). Scale effects are also examined for a case-study historic envelope (≈7 m in total size, 5 mm in thickness), and one of its 2.58 m × 3.3 m large glass components. Furthermore, a simplified empirical approach based on analytical formulations and normalized charts is proposed for a preliminary vulnerability assessment of historic monolithic glass envelopes, including parameters to account for impactor features and glass panel size/thickness, based on vibration-frequency considerations

The interaction between rhizobacteria and the hyperaccumulator fern Pteris vittata in arsenic transformation

L\u2019arsenico \ue8 un elemento ubiquitario che ricorre con naturale abbondanza nella crosta terrestre. \uc8 tossico sia per le piante che per gli animali e ne \ue8 stato dimostrato il potere cancerogeno nell\u2019uomo (Ng, 2005). La tossicit\ue0 dell\u2019As nei confronti della salute umana si esplica in un ampio range di patologie che vanno da lesioni cutanee a cancro ai reni, allo stomaco, al fegato (Smith et al., 1992). La contaminazione da As nelle acque ad uso domestico \ue8 stata riportata in pi\uf9 di 70 paesi diversi, e si stima che abbia compromesso la salute di pi\uf9 di 150 milioni di persone nel mondo (Ravenscroft et al., 2009). Data la sua ampia distribuzione ed elevata tossicit\ue0, la contaminazione da arsenico rappresenta oggigiorno un problema di importanza mondiale (Ng et al., 2003). Un interessante caso di studio \u2013 in esame in questo lavoro di dottorato \u2013 \ue8 rappresentato dall\u2019area di Scarlino, un Sito con priorit\ue0 di risanamento di Interesse Regionale (SRI). In questo contesto la contaminazione di suoli e falde \ue8 stata provocata dall\u2019accumulo di scorie di arsenopirite derivanti dall\u2019incenerimento del minerale per la produzione di acido solforico presso l\u2019impianto industriale Nuova Solmine operante nel sito. Aldil\ue0 del fattore di contaminazione antropico, tutta l\u2019area di Scarlino \ue8 allo stesso tempo contaminata per cause naturali, i suoli di tutto il comune, al di fuori delle aree industriali, presentano infatti una concentrazione media di As pari a 140 mg/kg. Dal punto di vista biotecnologico un approccio che potrebbe attenuare questa problematica \ue8 rappresentato dalla fitoestrazione assistita da batteri. La fitobonifica in generale \ue8 l\u2019insieme delle tecnologie a basso costo e impatto ambientale che prevede l\u2019uso di piante vascolari per il risanamento in situ di suoli, fanghi e sedimenti contaminati. In particolare, in caso di suoli contaminati da As o metalli, la fitoestrazione \u2013 che prevede la concentrazione dei contaminanti nei tessuti vegetali e la loro successiva raccolta \u2013 rappresenta la strategia di maggior successo (Khan, 2005). I microrganismi hanno un ruolo fondamentale in tale processo. Di fatto i batteri possono incrementare la mobilit\ue0 dell\u2019arsenico dalla matrice suolo (stimolandone l\u2019uptake da parte della pianta) mentre rizobatteri promotori delle crescita vegetale (PGPR) possono elicitare la produzione in biomassa vegetale (Abou-Shanab et al., 2003) migliorando in entrambi i casi l\u2019efficienza del sistema. sulla base dei risultati ottenuti \ue8 possibile affermare che: L'elevata contaminazione presente nell\u2019area industriale ha esercitato una notevole pressione selettiva sulla cenosi batterica autoctona verso una comunit\ue0 pi\uf9 tollerante, caratterizzata da un\u2019elevata biodiversit\ue0, resistenza e potenziale abilit\ue0 nella trasformazione degli ossianioni As(III) e As(V); \u2022 All\u2019interno dell\u2019area, laddove la contaminazione \ue8 pi\uf9 severa si \ue8 evidenziata una prevalenza di batteri Gram positivi appartenenti a phylum Firmicutes e Actinobacteria e ceppi a cui si riconducono interessanti tratti coinvolti nel metabolismi dell\u2019arsenico; \u2022 Gli isolati riconducibili alla specie Delftia lacustris, Pseudomonas putida, in grado di ridurre l\u2019As(V) in vitro con elevata efficienza, potrebbero potenzialmente solubilizzare l\u2019As nel suolo; \u2022 Tra i membri della comunit\ue0 batterica isolati in coltura pura, per lo pi\uf9 tra i Gammaproteobatteri, hanno evidenziato diversi tratti PGP risultando di particolare interesse in una prospettiva di fitobonifica secondo un protocollo di bioaugmentation; Abstract \u2013 Riassunto 22 \u2022 Gli isolati Ochrobactrum cytisi OTU E, Pseudomonas putida OTU N and Achromobacter marplatensis OTU P sono stati selezionati e testati in una prova di fitoestrazione assistita da batteri in presenza delle felce iperaccumulatrice di As P. vittata. Essi hanno esercitato effetti positivi sia per quanto riguarda la produzione in biomassa che per quanto riguarda l\u2019efficienza di estrazione del contaminante dal suolo. Invero tutte le felci, con o senza inoculo, sono state in grado di estrarre delle discrete quantit\ue0 di As anche se, in presenza dei ceppi PGP, si sono dimostrate pi\uf9 efficaci. Si stanno momentaneamente attendendo i risultati di una seconda prova di fitoestrazione assistita da altri ceppi PGP selezionati (P. putida, Delftia lacustris, B. thuringiensis, Variovorax paradoxus, Pseudoxanthomonas mexicana). Queste stime preliminari consentiranno quindi di meglio valutare il potenziale del sistema di fitoestrazione in esami e di programmare quindi una prova in scala pilota nel sito industriale di Scarlino. Concludendo, si ritiene che un sistema integrato di felci iperaccumulatrici e batteri PGP resistenti all\u2019arsenico possa essere un valido strumento per attuare la bonifica nell\u2019area.Arsenic is an ubiquitous element which occurs naturally in the earth's crust. Arsenic is toxic to both plants and animals and inorganic arsenicals are proven carcinogens in humans (Ng, 2005). Arsenic toxicity to human health ranges from skin lesions to brain, liver, kidney, and stomach cancer (Smith et al., 1992). Arsenic contamination of groundwater used for domestic supplies has been reported in over 70 countries, affecting health of an estimated 150 million people (Ravenscroft et al., 2009). Because of its wide distribution and marked toxic effects, arsenic contamination is a problem of global concern. Inorganic arsenic is indeed regarded as the number one toxin in the USEPA list of priority pollutants (Ng et al., 2003). In this respect, an interesting case study is that discussed in this PhD thesis focusing on the Scarlino area, a Site of Regional Interest (SRI) which requires prominent attention from the environmental point of view. The contamination in this context is the result of dumping of ash from arsenopyrite roasting for more than 30 years as a consequence of sulfuric acid production by the Nuova Solmine Company operating with industrial facilities in this site. Disposal of such ash in addition to the natural arsenic background has thus provoked either a serious soil contamination or a diffuse pollution of aquifers within the whole industrial district, where As can be detected in an average concentration of 140 mg/kg. An approach that might alleviate this problem is represented by the biotechnological option defined as microbe-enhanced phytoremediation. Phytoremediation is a low-cost and eco-friendly technology that uses vascular plants for in situ environmental restoration and reclamation of contaminated soils, sludges and sediments. Particularly, in the case of As contamination, phytoextraction \u2013 which is the removal of toxic metals/metalloids from soil or whatever other environmental matrix and their concentration into the harvestable plant portion \u2013 appears quite useful (Khan, 2005). Microorganisms are known to play a very important role in this process. Actually, bacteria can enhance the mobility of arsenic in the soil matrix (eliciting the metalloid uptake by plants) while plant growth promoting rhizobacteria (PGPR) can improve plant biomass production (Abou- Shanab et al., 2003a; Glick et al., 1995; Glick, 2003). on the basis of obtained data it can be stated that:The high contamination due to arsenic and heavy metals present in the Nuova Solmine industrial area has determined a selection of the soil autochthonous bacterial cenoses towards a more tolerant and well adapted community, with wide biodiversity, resistance and As-transforming potential; \u2022 Most of the strains identified in the area with the highest pollutant concentrations (M, the arsenopyrite ash dumping pile) belonged to Gram positive Firmicutes and Actinobacteria, including strains possessing interesting genotypic traits involved in As transformation; \u2022 The isolates belonging to Delftia lacustris, and Pseudomonas putida specie reduced As(V) in vitro at high efficiency also showing the ability to solubilize arsenic in soils; \u2022 Among the members of the above mentioned bacterial community isolated in pure culture, strains belonging mainly to Gamma-proteobacteria were carrying particular PGP traits useful in a phytoremediation perspective based on bioaugmentation;Ochrobactrum cytisi, Pseudomonas putida and Achromobacter marplatensis were selected and tested for a microbe-enhanced phytoextraction experiment in association with the hyperaccumulator fern P. vittata. They exerted positive effects on both plant biomass production and total phytoextraction efficiency when compared with the not inoculated plants. However, all the plants \u2013 with or without bacterial inoculants \u2013 were able to extract an appreciable amount of As; however, where the inocula were present, ferns lowered As concentration in soil more effectively. The results of a second phytoextraction trial with another selection of As-resistant PGP strain (P. putida, Delftia lacustris, B. thuringiensis, Variovorax paradoxus, Pseudoxanthomonas mexicana) are coming. When completed, these preliminary evidences will allow either to evaluate the phytoextraction potential of the bacterial strains tested so far at lab scale or to schedule a future pilot trial at the Scarlino contaminated site. In conclusion an integrated system of plants and bacteria would be perfected as a reliable remediation tool to be applied in the Scarlino industrial area

Effect of the Glucagon-Like Peptide-1 Receptor Agonists on Autonomic Function in Subjects with Diabetes: A Systematic Review and Meta-Analysis

Background: In addition to the metabolic effects in diabetes, glucagon-like peptide 1 receptor (GLP-1R) agonists lead to a small but substantial increase in heart rate (HR). However, the GLP-1R actions on the autonomic nervous system (ANS) in diabetes remain debated. Therefore, this meta-analysis evaluates the effect of GLP-1R agonist on measures of ANS function in diabetes. Methods: According to the Cochrane Collaboration and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, we conducted a meta-analysis considering clinical trials in which the autonomic function was evaluated in diabetic subjects chronically treated with GLP-1R agonists. The outcomes were the change of ANS function measured by heart rate variability (HRV) and cardiac autonomic reflex tests (CARTs). Results: In the studies enrolled, HR significantly increased after treatment (P<0.001), whereas low frequency/high frequency ratio did not differ (P=0.410); no changes in other measures of HRV were detected. Considering CARTs, only the 30:15 value derived from lying-to-standing test was significantly lower after treatment (P=0.002), but only two studies reported this measurement. No differences in other CARTs outcome were observed. Conclusion: The meta-analysis confirms the HR increase but seems to exclude an alteration of the sympatho-vagal balance due to chronic treatment with GLP-1R agonists in diabetes, considering the available measures of ANS function

Emotion Recognition Deficits in the Differential Diagnosis of Amnestic Mild Cognitive Impairment: A Cognitive Marker for the Limbic-Predominant Phenotype.

AbstractObjective:Late-onset amnestic mild cognitive impairment (aMCI) with long disease course and slow progression has been recently recognized as a possible phenotypical expression of a limbic-predominant neurodegenerative disorder. Basic emotion recognition ability crucially depending on temporo-limbic integrity is supposed to be impaired in this group of MCI subjects presenting a selective vulnerability of medio-temporal and limbic regions. However, no study specifically investigated this issue.Methods:Hereby, we enrolled 30 aMCI with a biomarker-based diagnosis of Alzheimer's disease (i.e., aMCI-AD, n = 16) or a biomarker evidence of selective medio-temporal and limbic degeneration (aMCI-mTLD, n = 14). Ekman-60 Faces Test (Ek-60F) was administered to each subject, comparing the performance with that of 20 healthy controls (HCs).Results:aMCI-mTLD subjects showed significantly lower Ek-60F global scores compared to HC (p = 0.001), whose performance was comparable to aMCI-AD. Fear (p = 0.02), surprise (p = 0.005), and anger (p = 0.01) recognition deficits characterized the aMCI-mTLD performance. Fear recognition scores were significantly lower in aMCI-mTLD compared to aMCI-AD (p = 0.04), while no differences were found in other emotions.Conclusions:Impaired social cognition, suggested by defective performance in emotion recognition tasks, may be a useful cognitive marker to detect limbic-predominant aMCI subjects among the heterogeneous aMCI population

In vivo endophytic, rhizospheric and epiphytic colonization of vitis vinifera by the plant-growth promoting and antifungal strain pseudomonas protegens MP12

An evaluation was conducted of the colonization of Pseudomonas protegens MP12, a plantgrowth promoting and antagonistic strain, inoculated in vine plants during a standard process of grapevine nursery propagation. Three in vivo inoculation protocols (endophytic, rhizospheric, and epiphytic) were implemented and monitored by means of both culture-dependent and independent techniques. Endophytic treatment resulted in the colonization of the bacterium inside the vine cuttings, which spread to young leaves during the forcing period. Microscopy analysis performed on transformed dsRed-tagged P. protegens MP12 cells confirmed the bacterium’s ability to penetrate the inner part of the roots. However, endophytic MP12 strain was no longer detected once the plant materials had been placed in the vine nursery field. The bacterium also displayed an ability to colonize the rhizosphere and, when the plants were uprooted at the end of the vegetative season, its persistence was confirmed. Epiphytic inoculation, performed by foliar spraying of cell suspension, was effective in controlling artificially-induced Botrytis cinerea infection in detached leaves. The success of rhizospheric and leaf colonization in vine plants suggests potential for the future exploitation of P. protegens MP12 as biofertilizer and biopesticide. Further investigation is required into the stability of the bacterium’s colonization of vine plants under real-world conditions in vineyards

Evaluation of the Potential Use of a Collagen-Based Protein Hydrolysate as a Plant Multi-Stress Protectant

Protein hydrolysates (PHs) are a class of plant biostimulants used in the agricultural practice to improve crop performance. In this study, we have assessed the capacity of a commercial PH derived from bovine collagen to mitigate drought, hypoxic, and Fe deficiency stress in Zea mays. As for the drought and hypoxic stresses, hydroponically grown plants treated with the PH exhibited an increased growth and absorption area of the roots compared with those treated with inorganic nitrogen. In the case of Fe deficiency, plants supplied with the PH mixed with FeCl3 showed a faster recovery from deficiency compared to plants supplied with FeCl3 alone or with FeEDTA, resulting in higher SPAD values, a greater concentration of Fe in the leaves and modulation in the expression of genes related to Fe. Moreover, through the analysis of circular dichroism spectra, we assessed that the PH interacts with Fe in a dose-dependent manner. Various hypothesis about the mechanisms of action of the collagen-based PH as stress protectant particularly in Fe-deficiency, are discussed