421 research outputs found
Energy performance of diaphragm walls used as heat exchangers
The possibility of equipping diaphragm walls as ground heat exchangers to meet the full or partial heating and cooling demands of overlying or adjacent buildings has been explored in recent years. In this paper, the factors affecting the energy performance of diaphragm walls equipped as heat exchangers are investigated through finite element modelling. The numerical approach employed is first validated using available experimental data and then applied to perform parametric analyses. Parameters considered in the analysis include panel width, the ratio between the wall and excavation depths, heat transfer pipe spacing, concrete cover, heat-carrier fluid velocity, concrete thermal properties and the temperature difference between the air within the excavation and the soil behind the wall. The results indicate that increasing the number of pipes by reducing their spacing is the primary route to increasing energy efficiency in the short term. However, the thermal properties of the wall concrete and the temperature excess within the excavation space are also important, with the latter becoming the most significant in the medium to long term. This confirms the benefits of exploiting the retaining walls installed for railway tunnels and metro stations where additional sources of heat are available
DETERMINAZIONE INNOVATIVA DEL ROTENONE NEGLI OLI DI OLIVA DA AGRICOLTURA BIOLOGICA MEDIANTE SPETTROMETRIA DI MASSA TANDEM
Il rotenone, pesticida naturale utilizzato in agricoltura biologica su una grande varietà di colture, è stato determinato quantitativamente mediante Atmosheric Pressure Chemical Ionisation Spettrometria di Massa Tandem (APCI MS/MS) nelle olive e negli oli di oliva ottenuti dopo trattamento in una prova di campo che ha interessato la cv Carolea in Calabria. La tecnica analitica ha previsto la realizzazione di esperimenti “Multiple Reaction Monitoring” (MRM) utilizzando uno standard interno ottenuto per sintesi. Le quantità rilevate sono comprese tra 9 mg/Kg di olio dopo 1 giorno dal trattamento e 0.15 mg/Kg di olio dopo 1 mese circa dal trattamento. Quest’ultimo valore è molto più elevato dei 40 µg/Kg permessi dalla legislazione italiana
Bergamot natural products eradicate cancer stem cells (CSCs) by targeting mevalonate, Rho-GDI-signalling and mitochondrial metabolism
Here, we show that a 2:1 mixture of Brutieridin and Melitidin, termed “BMF”, has a statin-like properties, which
blocks the action of the rate-limiting enzyme for mevalonate biosynthesis, namely HMGR (3-hydroxy-3-methylglutaryl-
CoA-reductase). Moreover, our results indicate that BMF functionally inhibits several key characteristics
of CSCs. More specifically, BMF effectively i) reduced ALDH activity, ii) blocked mammosphere
formation and iii) inhibited the activation of CSC-associated signalling pathways (STAT1/3, Notch and Wnt/
beta-catenin) targeting Rho-GDI-signalling. In addition, BMF metabolically inhibited mitochondrial respiration
(OXPHOS) and fatty acid oxidation (FAO). Importantly, BMF did not show the same toxic side-effects in normal
fibroblasts that were observed with statins. Lastly, we show that high expression of the mRNA species encoding
HMGR is associated with poor clinical outcome in breast cancer patients, providing a potential companion
diagnostic for BMF-directed personalized therapy
Hydrolase–like catalysis and structural resolution of natural products by a metal–organic framework
The exact chemical structure of non–crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal–organic framework (MOF) with alcohol–containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so–formed chiral fragments and absolute determination of the organic structure by single–crystal X–ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigram available solid catalyst opens the door to determine the absolute configuration of ketal compounds regardless degradation sensitiveness, and also to design extremely–mild metal–free solid–catalysed processes without formal acid protons.This work was supported by the Ministero dell’Istruzione, dell’Università e della Ricerca
(Italy) and the MINECO (Spain) (Projects CTQ2016-75671-P, CTQ 2017-86735-P,
RTC-2017-6331-5, Severo Ochoa program SEV-2016-0683 and Excellence Unit “Maria
de Maeztu” MDM-2015-0538). R.B. thanks the MIUR (Project PON R&I FSE-FESR
2014–2020) for grant. L.B wishes to thank Italian MIUR for grant n. AIM1899391–1 in
the framework of the project “Azione I.2, Mobilità dei Ricercatori, PON R&I 2014–2020”.
Thanks are also extended to the “2019 Post-doctoral Junior Leader-Retaining Fellowship,
la Caixa Foundation (ID100010434 and fellowship code LCF/BQ/PR19/11700011” (J. F.-
S.). S. S.-N. thanks ITQ for the concession of a contract. D.A. acknowledges the financial
support of the Fondazione CARIPLO/“Economia Circolare: ricerca per un futuro sostenibile”
2019, Project code: 2019–2090, MOCA. E.P. acknowledges the financial support
of the European Research Council under the European Union’s Horizon 2020 research
and innovation program/ERC Grant Agreement No. 814804, MOF-reactors
Degradation of Penicillinic Antibiotics and β-Lactamase Enzymatic Catalysis in a Biomimetic Zn-Based Metal–Organic Framework
β-Lactam antibiotics are one of the most commonly prescribed drugs to treat bacterial infections. However, their use has been somehow limited given the emergence of bacteria with resistance mechanisms, such as β-lactamases, which inactivate them by degrading their four-membered β-lactam rings. So, a total knowledge of the mechanisms governing the catalytic activity of β-lactamases is required. Here, we report a novel Zn-based metal–organic framework (MOF, 1), possessing functional channels capable to accommodate and interact with antibiotics, which catalyze the selective hydrolysis of the penicillinic antibiotics amoxicillin and ceftriaxone. In particular, MOF 1 degrades, very efficiently, the four-membered β-lactam ring of amoxicillin, acting as a β-lactamase mimic, and expands the very limited number of MOFs capable to mimic catalytic enzymatic processes. Combined single-crystal X-ray diffraction (SCXRD) studies and density functional (DFT) calculations offer unique snapshots on the host-guest interactions established between amoxicillin and the functional channels of 1. This allows to propose a degradation mechanism based on the activation of a water molecule, promoted by a Zn-bridging hydroxyl group, concertedly to the nucleophilic attack to the carbonyl moiety and the cleaving of C−N bond of the lactam ring.This work was supported by the MICINN (Spain) (Projects PID2019-104778GB-I00, PID2020-115100GB-I00, and Excellence Units “Severo Ochoa” CEX2021-001230-S and “Maria de Maeztu” CEX2019-000919-M) and the Ministero dell'Istruzione, dell'Università e della Ricerca (Italy). The work has also been funded by Generalitat Valenciana, Prometeo Grupos de Investigación de Excelencia (PROMETEU/2021/054). D.A. also acknowledges the financial support of the European Union - NextGenerationEU under the National Recovery and Resilience Plan (NRRP) of Ministero dell'Università e della Ricerca (MUR) (Project code PE0000021, “Network 4 Energy Sustainable Transition - NEST). Thanks are also extended to the 2019 Post-doctoral Junior Leader-Retaining Fellowship, la Caixa Foundation (ID100010434 and fellowship code LCF/BQ/PR19/11700011), the “Generalitat Valenciana” (SEJI/2020/034) and the “Ramón y Cajal” program (J.F.-S.). E.P. acknowledges the financial support of the European Research Council under the European Union's Horizon 2020 research and innovation programme / ERC Grant Agreement No 814804, MOF-reactors. S.S.-N. thanks a fellowship from MINECO (project number CTQ 2017–86735-P). This study forms part of the Advanced Materials programme (MFA/2022/048) and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana. Financial support from Dipartimento di Chimica e Tecnologie Chimiche (CTC), Università della Calabria, is also gratefully acknowledged for computational investigation
Postmortem CT pulmonary findings in SARS-CoV-2-positive cases: correlation with lung histopathological findings and autopsy results
Introduction/purpose Postmortem computed tomography (PMCT) is a valuable tool for analyzing the death of patients with SARS-CoV-2 infection. The purpose of this study was to investigate the correlation between PMCT lung findings in autopsy cadavers positive for SARS-CoV-2 infection and the severity of COVID-19 lung disease by histopathological analysis.Materials and methods We reviewed chest PMCT findings, paying particular attention to the lung parenchyma, in 8 autopsy cases positive for SARS-CoV-2. Correlations between chest PMCT and histopathological findings were assessed. Clinical conditions and comorbidities were also recorded and discussed. The primary cause of death was finally considered.Results In 6/8 cases, pulmonary PMCT findings were massive consolidation (4/8) and bilateral diffuse mixed densities with a crazy-paving pattern (2/8). These cases showed severe pulmonary signs of COVID-19 at histopathological analysis. In the remaining 2/8 cases, pulmonary PMCT findings were scant antideclive ground-glass opacities in prevalent gradient densities attributed to hypostasis. In 4/8 cases with massive consolidations, important comorbidities were noted. In 6/8 cases with severe pulmonary histopathological signs of lung COVID-19, autopsy found that the cause of death was cardiorespiratory failure. In the remaining 2/8 cases, histopathological analysis revealed lung alterations due to edema and some signs of SARS-CoV-2 infection; the cause of death was not attributed to SARS-CoV-2 infection (Table 1).Discussion and conclusion Chest PMCT findings correlate with the severity of COVID-19 lung disease at histopathology examination. According to our results, there may also be a relationship between cause of death and PMCT findings in COVID-19, which must be critically analyzed considering clinical antemortem data
Postmortem CT pulmonary findings in SARS-CoV-2-positive cases: correlation with lung histopathological findings and autopsy results
Introduction/purpose: Postmortem computed tomography (PMCT) is a valuable tool for analyzing the death of patients with SARS-CoV-2 infection. The purpose of this study was to investigate the correlation between PMCT lung findings in autopsy cadavers positive for SARS-CoV-2 infection and the severity of COVID-19 lung disease by histopathological analysis. Materials and methods: We reviewed chest PMCT findings, paying particular attention to the lung parenchyma, in 8 autopsy cases positive for SARS-CoV-2. Correlations between chest PMCT and histopathological findings were assessed. Clinical conditions and comorbidities were also recorded and discussed. The primary cause of death was finally considered. Results: In 6/8 cases, pulmonary PMCT findings were massive consolidation (4/8) and bilateral diffuse mixed densities with a crazy-paving pattern (2/8). These cases showed severe pulmonary signs of COVID-19 at histopathological analysis. In the remaining 2/8 cases, pulmonary PMCT findings were scant antideclive ground-glass opacities in prevalent gradient densities attributed to hypostasis. In 4/8 cases with massive consolidations, important comorbidities were noted. In 6/8 cases with severe pulmonary histopathological signs of lung COVID-19, autopsy found that the cause of death was cardiorespiratory failure. In the remaining 2/8 cases, histopathological analysis revealed lung alterations due to edema and some signs of SARS-CoV-2 infection; the cause of death was not attributed to SARS-CoV-2 infection (Table 1). Discussion and conclusion: Chest PMCT findings correlate with the severity of COVID-19 lung disease at histopathology examination. According to our results, there may also be a relationship between cause of death and PMCT findings in COVID-19, which must be critically analyzed considering clinical antemortem data
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A high-resolution map of human evolutionary constraint using 29 mammals.
The comparison of related genomes has emerged as a powerful lens for genome interpretation. Here we report the sequencing and comparative analysis of 29 eutherian genomes. We confirm that at least 5.5% of the human genome has undergone purifying selection, and locate constrained elements covering ∼4.2% of the genome. We use evolutionary signatures and comparisons with experimental data sets to suggest candidate functions for ∼60% of constrained bases. These elements reveal a small number of new coding exons, candidate stop codon readthrough events and over 10,000 regions of overlapping synonymous constraint within protein-coding exons. We find 220 candidate RNA structural families, and nearly a million elements overlapping potential promoter, enhancer and insulator regions. We report specific amino acid residues that have undergone positive selection, 280,000 non-coding elements exapted from mobile elements and more than 1,000 primate- and human-accelerated elements. Overlap with disease-associated variants indicates that our findings will be relevant for studies of human biology, health and disease
A comprehensive evaluation of the kinetic method applied in the determination of the proton affinity of the nucleic acid molecules
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