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Associate Editor ASCE Journal of Bridge Engineering
No full texthttps://ascelibrary.org/page/jbenf2/editorialboar
Challenges and opportunities in the supervised learning of quantum circuit expectation values
No full textRecently, deep neural networks have been proven capable of predicting output expectation values of certain random quantum circuits via a supervised learning approach. Here we investigate the potential of this possible approach to the emulation of quantum circuits, testing both its limitations and the successful applications where it might outperform conventional direct simulation methods. The testbeds we consider are circuits often employed in variational quantum algorithms, featuring layers of cnot gates alternated with single-qubit random rotations. On the one hand, we find that the computational cost of supervised learning scales exponentially with the interlayer variance of the random angles. This allows for entering a promising regime for quantum advantage, where quantum computers could easily outperform classical neural networks. On the other hand, circuits featuring only interqubit angle variations are easily emulated. In fact, thanks to a suitable scalable design, the trained networks accurately predict the expectation values of larger and deeper circuits than those used for training, even reaching circuit sizes, which, as we numerically show, are computationally intractable for the most common simulation libraries of state-vector and tensor-network algorithms. A repository of test data in the intractable regime is provided. We also analyze the most common metrics for the entanglement content, the expressibility, and the classical computational cost of quantum circuits, finding that they do not distinguish the easy from the hard circuit configurations
Tra architettura e ingegneria: Johann Lucas von Hildebrandt e la sua costellazione romana dal 1682 al 1693 circa (Carlo Fontana, Giulio Cerutti, Abraham Paris e Cornelis Meyer)
No full textL'opera di Johann Lucas von Hildebrandt (1668–1745) è sostanzialmente conosciuta sino alle pieghe delle committenze minori, ma rimane in parte oscura la sua formazione architettonica, circoscritta a una decina di anni, trascorsi perlopiù a Roma dal 1682 al 1693 circa. Le fonti documentano che il giovane Hildebrandt stabilì nel corso del suo apprendistato rapporti continuativi con Carlo Fontana
(1638–1714) (figg. 1b, 3) e Giulio Cerutti (doc. 1640/50–1695).
E, sebbene non documentati, probabilmente con Abraham Paris (1641–1716).2Ma, aldilà di questi dati, non conosciamo la durata della collaborazione di Hildebrandt con i suoi precettori né i cantieri o i progetti a cui partecipò.
Il saggio tenta di fornire alcune risposte a queste domande sinora inevase e legate all’apprendistato dell’architetto. In particolare, le domande ricorrenti potrebbero essere le seguenti: come Hildebrandt entrò in contatto con l’atelier di Carlo Fontana e come prestò, simultaneamente, la sua assistenza all’ingegnere Giulio Cerutti? Il giovane architetto fu presente o meno nella scuola del tecnico Abraham Paris, anch’egli collega e collaboratore di Fontana e di Cerutti? Come era composto l’ambiente professionale romano, in cui il nostro progettista aveva mosso le sue prime esperienze? Chi erano stati i suoi colleghi apprendisti?
Per definire meglio l’ambiente in cui il giovane Hildebrandt si muoveva durante la sua variegata formazione si è scelto quindi di analizzare le biografie dei suoi possibili contatti. O comunque la descrizione dei protagonisti che in quegli anni si muovevano sul comune crinale compreso tra l’architettura, l’ingegneria e l’idraulica sia sul piano professionale (Carlo Fontana, Giulio Cerutti, ma anche Abraham Paris e il tecnico papale Cornelis Meyer), sia su quello della frequentazione dei suoi coetanei (Girolamo e Francesco Fontana, con note dedicate anche ad Agostino Cerutti e Romano Fortunato Carapecchia)
The Development and Statistical Analysis of a Material Strength Database of Existing Italian Prestressed Concrete Bridges
No full textThis paper reports a statistical analysis of a database archiving information on the strengths of the materials in existing Italian bridges having pre- and post-tensioned concrete beams. Data were collected in anonymous form by analyzing a stock of about 170 bridges built between 1960 and 2000 and located in several Italian regions. To date, the database refers to steel reinforcing bars, concrete, and prestressing steel, whose strengths were gathered from design nominal values, acceptance certificates, and in situ test results, all derived by consulting the available documents for each examined bridge. At first, this paper describes how the available data were collected. Then, the results of a statistical analysis are presented and commented on. Moreover, goodness-of-fit tests are carried out to verify the assumption validity of a normal distribution for steel reinforcing bars and prestressing steel, and a log-normal distribution for concrete. The database represents a valuable resource for researchers and practitioners for the assessment of existing bridges. It may be applied for the use of prior knowledge within a framework where Bayesian methods are included for reducing uncertainties. The database provides essential information on the strengths of the materials to be used for a simulated design and/or for verification in the case of limited knowledge. Goodness-of-fit tests make the collected information very useful, even if probabilistic methods are applied
Preliminary results from concentrated impact tests on a school desk with life-saving function in case of earthquakes
No full textThis article presents the latest developments involving an innovative life-saving school desk, result of a multidisciplinary design process having as goal a limited increment of weight, dimensions, and costs as compared to conventional school desks, while significantly improving the capacity to resist static and dynamic loads, as those that could be experienced in case of seismic damages of the building. Specifically, this study reviews the structural concept behind the proposed school desks and illustrates a selection of some preliminary results of an experimental campaign in which the performances of full-scale prototypes were evaluated under impact loadings. Attention was given to the definition of a testing methodology that is an extension of current prescriptions for testing conventional school desk and that could be easily replicable in a structural engineering laboratory. The experimental outcomes were monitored using conventional contact sensors as well as computer-vision methodologies for displacement tracking, to gain insight into the response of the tested school desks under impact loadings
Dynamic Behaviour and Seismic Response of Scoured Bridge Piers
No full textThis study explores the transverse response of bridge piers in riverbeds under a multi-hazard scenario, involving seismic actions and scoured foundations. The combined impact of scour on foundations’ stability and on the dynamic stiffness of soil–foundation systems makes bridges more susceptible to earthquake damage. While previous research has extensively investigated this issue for bridges founded on piles, this work addresses the less explored but critical scenario of bridges on shallow foundations, typical of existing bridges. A comprehensive soil–foundation structure model is developed to be representative of the transverse response of multi-span and continuous girder bridges, and the effects of different scour scenarios and foundation embedment on the dynamic stiffness of the soil–foundation sub-systems are investigated through refined finite element models. Then, a parametric investigation is conducted to assess the effects of scour on the dynamic properties of the systems and, for some representative bridge prototypes, the seismic response at scoured and non-scoured conditions are compared considering real earthquakes. The research results demonstrate the significance of scour effects on the dynamic properties of the soil–foundation structure system and on the displacement demand of the bridge decks
Coordination chemistry of N-heterocyclic carbene gold complexes and their catalytic and anticancer activities
No full textOver the past two decades, N-heterocyclic carbenes (NHCs) have gained significant attention as
ligands, offering a versatile alternative to traditional phosphorus-based (e.g., phosphines, phosphites)
and nitrogen-based (e.g., amines, imines) ligands. NHCs have been extensively studied in coordination
chemistry, particularly for their strong σ-donor properties, making them exceptional ligands for
coinage metals, especially gold(I). NHC-gold(I) complexes, with gold in a d10 electronic configuration,
have found widespread applications in catalysis and as anticancer agents. In contrast, square planar
NHC-gold(III) complexes (d8 electronic configuration) remain relatively underexplored. Although the
practical halogen oxidative addition to gold(I) represents the predominant approach to obtaining
gold(III) compounds, several observations remain unexplained, such as the occasional absence of
expected products, the occurrence of reversible reduction, or the manifestation of geometrical
isomerism in mixed halide Au(III) complexes. Furthermore, recent theoretical and experimental
studies have emphasized the distinction between formal and physical oxidation states, better described
as electronic distribution, undermining the concept of oxidation state +3 for square planar d8
complexes. Indeed, oxidation state formalisms often fall short in describing the electronic partitioning
in metal-ligand bonds. This new reinterpretation shakes up several aspects of gold(III) chemistry that
have been considered widely established. For example, gold-catalyzed reactions traditionally
attributed to oxidation state variations, such as the cyclization of propargyl amides, may instead be
influenced by other factors, like the presence of adventitious coordinating species. Further studies are
therefore necessary, considering the new interpretation between formal and physical oxidation states.
Thus, this PhD thesis investigates the synthesis, characterization, catalytic activity, and anticancer
potential of a series of NHC-gold(I/III)X (X = Cl, Br or I), with particular emphasis on understanding
the influence of ligand structures, oxidation states and halides as counterions on the cytotoxic and
catalytic activities. This thesis can be divided into four main topics:
1) Synthesis and characterization of NHC-gold(I/III) complexes.
2) Gold-catalyzed cycloisomerization of propargyl amides.
3) Mechanistic insights into oxidative addition reaction of halogen to NHC-gold(I) complexes.
4) Anti-cancer applications of NHC-gold(I/III) complexes.
1) Synthesis and characterization of NHC-gold complexes
In this first part of the thesis, two linear NHC-gold(I) chloride complexes displaying or not a plane of
symmetry, i.e., symmetric 1,3-dimethyl-imidazolyl-2yl gold chloride (1-Cl) and asymmetric 1-benzyl-
3-methyl-imidazolyl-2-yl gold chloride (2-Cl), have been initially synthesized through the "weak base
route."[1,2] The systems were kept as simple as possible to relegate the studies on the gold metal centre
by feasible computational calculations. The corresponding NHC-Au(III)Cl3 were then obtained
through oxidation with iodobenzene dichloride; both 1,3-dimethyl-imidazolyl-2yl gold trichloride (1-
Cl3) and 1-benzyl-3-methyl-imidazolyl-2-yl gold trichloride (2-Cl3) were obtained with high yield (up
to 90%).[3,4] The homolog series was then completed by changing halide (bromine or iodide) directly
bonded to the gold centre and by oxidizing the corresponding NHC-gold(I)X (X =Br or I). Hence, the
metathesis reaction of 1-Cl with sodium bromide led to the formation of a bis-carbene [(1,3-dimethyl-
NHC)2Au][AuBr2] complex (1bis-AuBr2) with a 74% yield.[ 5 ] The substitution of chloride with
bromide facilitated ligand scrambling, yielding the bis-carbene species with AuBr2
–
as counterion.
Conversely, the reaction of 2-Cl with an excess sodium bromide produced a mono-carbene 2-Br with
a 91% yield.[6] Oxidation of 1bis-AuBr2 and 2-Br with liquid bromine led to the formation of a mono-
carbene NHC-Au(III) tribromide, 1-Br3 and 2-Br3, with a 93% and 84% yield, respectively.[7] The
NHC-gold(I) iodide analogs were achieved through a metathesis reaction of 1-Cl or 2-Cl with a large
excess of sodium iodide, leading in both cases to a bis-carbene species with AuI2
-
as counterion,
namely 1bis-I (43% yield) and 2bis-I (68%).[8] Finally, the oxidation of 1bis-I with solid iodine resulted
in a mixture of mono- and bis-carbene species; indeed, a mixture of 1,3-dimethyl-NHC-AuI3 (1mono-
I3) and [(1,3-dimethyl-NHC)2AuI2][AuI2] (1bis-AuI2) was produced when 1bis-I was oxidized with
solid iodine. The oxidation of 2bis-I produced a mixture of 1-benzyl-3-methyl-NHC-AuI3 (2mono-I3)
and [(1-benzyl-3-methyl-NHC)2AuI2][I3/AuI4] (2bis-I3/AuI4) species. All the complexes were isolated
as crystals and completely characterized by infrared, 1H, 13C NMR spectroscopies and X-ray crystal
diffraction. Particularly, X-ray crystallography revealed notable features in the crystal structures: for
example, the Au–Ccarbene bond is longer in bis-carbene species than in mono-carbene species.
Additionally, despite the increase in the oxidation state of the gold center, the Au–Xtrans bond length is
shorter in gold(I) complexes than in gold(III) complexes. Finally, the square planar geometry of the
Au-X3 complexes is strikingly regular, leading to a slight compression of the Ccarbene-Au-Xcis bond
angles from 90°, along with a corresponding expansion of the Xcis-Au-Xtrans bond angles.
This argument is included in Chapter II., Sections 2.2 and 2.3.
2) Gold-catalyzed cycloisomerization of propargyl amides
In the second topic, the cycloisomerization of propargylic amides (oxazoles synthesis) was studied as
a benchmark reaction to assess the catalytic activities of the homologous series of NHC-Au(I) and
NHC-Au(III) complexes. This oxazole synthesis was found to be gold oxidation dependent, allowing
to selectively produce an aromatic oxazole with gold(III) catalysts or a methylenedihydrooxazole via
gold(I) catalysts. Hence, the selectivity of this gold-catalyzed reaction was studied in terms of the gold
oxidation state and the counterions. The previous NHC-gold(I) and NHC-gold(III) complexes were
tested in the cyclization reaction at room temperature, with and without the addition of silver salt,
AgPF6. Notably, only the 1-benzyl-3-methyl-gold(III) trichloride (2-Cl3) selectively yielded the
aromatic oxazole without the use of silver salt. Monitoring the reaction catalyzed by 2-Cl3 via 1H NMR
highlighted the initial formation of the methylenedihydrooxazole in the first two days that finally
converted to the aromatic oxazole over a week. With the addition of silver salt, the oxidation state of
the gold catalyst (gold(I) or gold(III)) did not affect the chemoselectivity of the cyclization. Indeed,
both methylenedihydrooxazole and the aromatic oxazole were obtained regardless of the gold
oxidation state. This observation removes any potential involvement of the oxidation state, while the
distinct halides directly bonded to the gold centre significantly impacted the selectivity. Finally, the
oxazole synthesis of an internal alkyne, specifically 4-methoxy-N-(3-phenylprop-2-ynyl) benzamide,
was also explored both in the presence and absence of silver salts under the previously established
conditions. However, no conversion was observed under any tested conditions. This result suggested
that the active gold metal fragment likely substitutes the terminal alkyne proton to initiate the catalytic
cycle rather than merely coordinating to the triple bond.
3) Mechanistic insights into oxidative addition reaction of halogen to NHC-gold(I) complexes.
For late transition metals, the d orbital energies can sometimes be lower than those of the ligand
orbitals, contrary to what is stated in the Ligand Field Theory. This phenomenon is notably observed
in certain square planar “d8” complexes. In such cases, the resulting σ-bonding orbital is primarily
localized on the metal center, while the antibonding orbital exhibits a stronger ligand contribution,
with electron density shifted toward the metal center. This reinterpretation of metal-ligand bonding in
square planar complexes is known as the Inverted Ligand Field (ILF) model. This model challenges
traditional views of oxidation states, suggesting that the reactivity of gold(III) complexes is strongly
governed by ligand-centered electronic effects. From this perspective, the complete lack of influence
of the gold oxidation state on the selectivity of the previous cycloisomerization prompted further
investigation into the oxidative addition mechanism to gold(I) complexes and the actual oxidation state
of gold, especially in the context of the ILF. Hence, in the third part of this work, the iodine and
bromine addition to the previous linear NHC-gold(I) chloride (1-Cl and 2-Cl) was investigated at room
temperature and at 75°, both experimentally and computationally. For the iodine addition, the
molecular structures highlighted the formation of trans-NHCAuI2Cl isomers for 1-Cl and 2-Cl, both
at room temperature and at 75°C. Conversely, the bromine addition was strongly case-sensitive; at
room temperature, the bromine addition to 1-Cl led to a mixture of cis and trans-NHC-AuBr2Cl
isomers in a 17:83 ratio while, in the same condition, a mixture composed of trans-isomer and a
completely brominated product was obtained for 2-Cl. Finally, performing the bromine addition at
75°C, a NHC-gold(III) tribromide product was achieved for both 1-Cl and 2-Cl. All the mixed halide
gold(III) complexes were isolated as crystals and characterized by elemental analysis, IR, UV-visible,
1H and 13C NMR spectroscopy, and X-ray crystal diffraction.
Computational studies were then performed by the CNR of Florence. DFT analysis reveals a stepwise
addition of the halogen atom to the linear gold(I) complex, occurring without a net change in the
electronic population of the metal. This observation aligns with the Inverted Ligand Field (ILF) model.
Furthermore, the DFT study indicates that this halogen addition mechanism proceeds through the
formation of a tri-coordinated intermediate. The stability of these intermediates is governed by the
spatial arrangement of the three ligands, carbene, the initial halide, and the newly added halide. The
intermediate stability is, in turn, influenced by the electronegativity of the coordinated halide leading
to preferential geometrical isomers as final outputs.
4) Anti-cancer applications of NHC-gold(I/III) complexes
Lung cancer remains a leading cause of cancer-related mortality worldwide, necessitating the
development of novel therapies to address severe side effects and the emergence of drug resistance.
Among the different types of lung cancer, non-small lung cancer cells (NSCLC) are the most diffused.
In this context, NHC-gold complexes have merged as significant promises in lung cancer therapies.
The cytotoxic activity of gold complexes is believed to be their capacity to target proteins. For
example, auranofin, the first gold-based drug FDA approved, is known to specifically manipulate the
redox environment by inhibiting redox enzymes[9]
and is a potent inhibitor of the thioredoxin reductase
system (TrxR).[10] Indeed, the TrxR system has been confirmed as a critical target in the proposed
mechanisms of action of gold complexes. Interestingly, the overexpression of thioredoxin reductase
systems as a defense response against oxidative stress is associated with several types of cancers,
including lung cancer. Therefore, NHC-gold compounds are highly considered for anticancer
therapies.
Hence, in the last part of the thesis, the cytotoxic activity of the previous NHC-gold complexes was
explored thanks to our collaboration with the University of Cincinnati. Two gold(I)-
triphenylphosphane complexes were also added to the cytotoxic study: complex 3, already tested
against breast cancer, and a new compound obtained by the direct reaction between 1-Cl and
triphenylphosphine (complex 4). A panel of NSCLC cell lines was utilized as cancer models in this
study. Gold compounds featuring triphenylphosphine ligands exhibited greater cytotoxicity compared
to homoleptic [(NHC)2-Au(I)]X complexes or heteroleptic NHC-Au(I)X and NHC-Au(III)X3
complexes. Additionally, the gold(I) halide complexes (1bis-AuBr2 and 2-Br) were found to be more
active than the corresponding NHC-gold(III) compound. At the same time, the presence of the benzyl
substituent enhanced the overall cytotoxic activity with respect to the methyl one. Among the tested
compounds, mixed-ligand gold(I) complexes with linear NHC-AuPPh3 (compound 3) and trigonal
NHC-Au(Cl)PPh3 (compound 4) arrangements around the central metal demonstrated the highest
cytotoxicity against lung cancer cells. Complexes 3 and 4 were also evaluated in normal non-tumor
human lung fibroblasts (IMR90 cell line) to investigate their selectivity against healthy cells.
Interestingly, both compounds exhibited higher selectivity against the NSCLC cell lines over the lung
fibroblasts, suggesting fewer side effects in future anticancer therapies. Finally, analysis of thioredoxin
reductase (TrxR) activity in treated cells revealed that these compounds effectively inhibit TrxR, the
gold compound's most widely recognized molecular target. Notably, compound 4 achieved over 80%
reduction in TrxR activity in lung cancer cells
Rassegna a: G. SANTUCCI, Chi è causa del suo mal pianga se stesso. Emilio Betti e «quel senso di autoresponsabilità, che i romani mostrano così vivo», «Atlante della cultura giuridica europea» (Bologna, il Mulino, 2024) p. 130
No full textA Flexible Derivation Approach for the Numerical Solution of Partial Differential Equations
No full textWe propose a new method for the numerical solution of boundary value problems associated to partial differential equations.
This method is based on standard approximation techniques, like numerical differentiation of univariate functions and curve
interpolation, so it can be easily generalized to high-dimensional problems. However, the concrete implementation of this method
requires the proper solution of a routing problem for the graph associated with the discretized domain N. This graph routing
problem has an immediate solution when N has a grid structure. Instead, when N has a mesh structure or is given by sparse
points, it is possible to take advantage of methods for two classical graph routing problems, that is, the Chinese postman problem
and the Eulerian path problem. However, it will be shown that these problems do not provide a sufficiently satisfactory solution,
hence, further study for non-structured grids is needed. A numerical experiment shows the effectiveness of the proposed method in the case of N with a grid structure
Development of Biopolymer-based Multifunctional Delivery Systems for Combination Cancer Therapy and Diagnosis
No full textCancer remains one of the most complex and life-threatening diseases, necessitating the development
of advanced drug delivery strategies for effective treatment. This thesis explores the design and
development of biopolymer-based multifunctional delivery systems tailored for combination
cancer therapy and diagnosis. Utilizing natural biopolymer like hyaluronic acid (HA) and
oligosaccharide like cyclodextrin (CD), both hydrogel-based and nanogel-based delivery platforms
were formulated to co-deliver hydrophilic and hydrophobic therapeutics with enhanced stability,
controlled release, and targeted tumor accumulation. Through Michael addition crosslinking,
thiolated HA was conjugated with vinyl sulfonated CD to create injectable hydrogels with tunable
viscoelastic properties. These hydrogels were further optimized for dual drug delivery,
demonstrating synergistic anticancer effects through in vitro release and cell viability studies.
Additionally, HA/CD-based nanogels and semi-interpenetrating polymer network systems were
engineered to enable precise drug loading, theranostic applications, and redox-responsive drug release
mechanisms. Comprehensive physicochemical characterizations, including rheology, DLS, Raman,
FTIR, SEM, and swelling/degradation studies, were performed to validate the functionality of
these systems. This research contributes to the advancement of biopolymer-based smart delivery
platforms for combination therapy, offering promising strategies for more efficient and personalized
cancer treatment