Building Block Approach Research Articles

Bottom-up construction of chiral metal-peptide assemblies from metal cluster motifs.

The exploration of artificial metal-peptide assemblies (MPAs) is one of the most exciting fields because of their great potential for simulating the dynamics and functionality of natural proteins. However, unfavorable enthalpy changes make forming discrete complexes with large and adaptable cavities from flexible peptide ligands challenging. Here, we present a strategy integrating metal-cluster building blocks and peptides to create chiral metal-peptide assemblies and get a family of enantiopure [R-/S-Ni3L2]n (n = 2, 3, 6) MPAs, including the R-/S-Ni6L4 capsule, the S-Ni9L6 trigonal prism, and the R-/S-Ni18L12 octahedron cage. X-ray crystallography shows MPA formation reactions are highly solvent-condition-dependent, resulting in significant changes in ligand conformation and discrete cavity sizes. Moreover, we demonstrate that a structure transformation from Ni18L12 to Ni9L6 in the presence of benzopyrone molecules depends on the peptide conformational selection in crystallization. This work reveals that a metal-cluster building block approach enables facile bottom-up construction of artificial metal-peptide assemblies.

Construction of ternary hierarchical heterostructures with favorable interfacial compatibility for ultrahigh photocatalytic H2O2 production

Sluggish charge transfer dynamics are still the key issue limiting the development of photocatalysis. In this study, CdS/ZnIn2S4/MIL-53-NH2 ternary hierarchical heterostructures were constructed via a building block approach, where ZnIn2S4 lamellae first grow on MIL-53-NH2 followed by CdS nanoparticle deposition. The favorable interfacial compatibility and ternary heterostructures contribute to rapid and multistep spatial charge transfer, which suppresses charge recombination. Therefore, ultrahigh H2O2 production of 1792 μmol·L−1 was obtained over CdS/Znln2S4/MIL-53-NH2 composites with visible light, pure water and ambient air, which is not only higher than that of each monomer and binary heterostructure but also better than those of most reported references. Notably, the apparent quantum yield reached 4.5 % at 400 nm, and the solar-to-H2O2 conversion efficiency was 0.081 % in pure water and ambient air. Additionally, H2O2 generation over CdS/Znln2S4/MIL-53-NH2 composites involves two-electron O2 reduction with ·O2- as an intermediate. This work may encourage heterostructure design for efficient photocatalytic H2O2 production.

A building block approach to retirement income design

Abstract This paper addresses the retirement income planning problem from the perspective of the four main building blocks of retirement income: state pension, mortality credits, investment strategies, and drawdown schedules. We detail how these building blocks interact to form a retiree's overall retirement income portfolio, and what trade-offs and interactions must be considered. We find that while access to each building block increases the retiree's certainty equivalent consumption, the most substantial contributor to this increase is from utilization of the mortality credit building block (i.e., annuities).

The surface tension of Martini 3 water mixtures.

The Martini model, a coarse-grained forcefield for biomolecular simulations, has experienced a vast increase in popularity in the past decade. Its building-block approach balances computational efficiency with high chemical specificity, enabling the simulation of organic and inorganic molecules. The modeling of coarse-grained beads as Lennard-Jones particles poses challenges for the accurate reproduction of liquid-vapor interfacial properties, which are crucial in various applications, especially in the case of water. The latest version of the forcefield introduces refined interaction parameters for water beads, tackling the well-known artifact of Martini water freezing at room temperature. In addition, multiple sizes of water beads are available for simulating the solvation of small cavities, including the smallest pockets of proteins. This work focuses on studying the interfacial properties of Martini water, including surface tension and surface thickness. Employing the test-area method, we systematically compute the liquid-vapor surface tension across various combinations of water bead sizes and for temperatures from 300 to 350K. These findings are of interest to the Martini community as they allow users to account for the low interfacial tension of Martini water by properly adjusting observables computed via coarse-grained simulations to allow for accurate matching against all-atom or experimental results. Surface tension data are also interpreted in terms of local enrichment of the various mixture components at the liquid-vapor interface by means of Gibbs' adsorption formalism. Finally, the critical scaling of the Martini surface tension with temperature is reported to be consistent with the critical exponent of the 3D Ising universality class.

Photocatalyzed Cascade Hydrogen Atom Transfers for Assembly of Multi-Substituted α-SCF3 and α-SCF2H Cyclopentanones.

A photocatalyzed formal (3+2) cycloaddition has been developed to construct original polysubstituted α-SCF3 cyclopentanones in a regio- and diastereoselective manner. This building block approach leverages trifluoromethylthio alkynes and branched/linear aldehydes, as readily available reaction partners, in consecutive hydrogen atom transfers and C-C bond formations. Difluoromethylthio alkynes are also compatible substrates. Furthermore, the potential for telescoped reaction starting from alcohols instead of aldehydes was demonstrated, as well as process automatization and scale-up under continuous microflow conditions. This prompted density functional theory (DFT) calculations to support a radical-mediated cascade process.

Photocatalyzed Cascade Hydrogen Atom Transfers for Assembly of Multi‐Substituted α‐SCF3 and α‐SCF2H Cyclopentanones

AbstractA photocatalyzed formal (3+2) cycloaddition has been developed to construct original polysubstituted α‐SCF3 cyclopentanones in a regio‐ and diastereoselective manner. This building block approach leverages trifluoromethylthio alkynes and branched/linear aldehydes, as readily available reaction partners, in consecutive hydrogen atom transfers and C−C bond formations. Difluoromethylthio alkynes are also compatible substrates. Furthermore, the potential for telescoped reaction starting from alcohols instead of aldehydes was demonstrated, as well as process automatization and scale‐up under continuous microflow conditions. This prompted density functional theory (DFT) calculations to support a radical‐mediated cascade process.

Unveiling GruPol: Predicting Electric and Electrostatic Properties of Macromolecules via the Building Block Approach.

Understanding electrostatics and electric properties of macromolecules is crucial in uncovering the intricacies of their behavior and functionality. The precise knowledge of these properties enhances our ability to manipulate and engineer macromolecules for diverse applications, spanning from drug design to materials science. Having that in mind, we present here the GruPol database approach to characterize and accurately predict dipole moments, static polarizabilities, and electrostatic potential of proteins and their subunits. The method involves partitioning of the electron density, calculated at the M06-HF/aug-cc-pVDZ level of theory, of small peptides into predefined building blocks that are averaged over the database. By manipulating and positioning these building blocks, GruPol enables the description of proteins assembled from over nearly 100 residual entries, allowing for efficient and precise computation of the above-mentioned properties across a broad range of proteins. The database enables the user to include solvent effects as well as define protonation states on the protein's backbone to account for pH variations. The precision of the proposed scheme is benchmarked against experimental data for myoglobin species.

Total Synthesis of a Peptide Diatom Sex Pheromone Bearing a Sulfated Aspartic Acid.

The peptide sex-inducing pheromone SIP+ (1) bearing an unusual sulfated aspartic acid residue induces sexual reproduction in diatom populations. Herein, we report the first total synthesis of SIP+ using both a sulfated building block approach and a solid-phase peptide synthesis (SPPS)-compatible late-stage sulfation strategy to assemble the natural product. The modular approaches provide concise routes to useful quantities of the natural product for future structure activity relationship studies examining the role of SIP+ in diatom biology.

Towards reliability assessment of ultra-wideband microwave leakage monitoring in detecting stringer debondings in composite airframes

Ultra-wideband guided electromagnetic waves have been proposed recently for non-destructive testing and structural health monitoring applications. Among the multitude of possible microwave waveguides, recent works explored the concept of microwave leakage monitoring to detect stringer debondings in hollow carbon composite structures. The principle is to monitor the wave propagation characteristics within the cavity formed by the stringer and the airframe skin using transmission measurements. Changes in the transmission path, e.g. occurring from microwave leakage in the debonded region, can be assessed through a damage indicator approach. To proof the reliability of this concept, an experimental campaign was carried out according to the building block approach typically used in aeronautics. First, a small-scale specimen with a debonded stringer was investigated in the laboratory to proof the methodology. Then, a large-scale fuselage segment was used for technology demonstration enabling stringer debonding with increasing severity through static and fatigue loading. The paper shows that the microwave characteristics in the waveguide (stringer tunnel) is affected by the debonding conditions according to its severity and depth. In addition, extending the same approach on a number of test cases, the probability of detection was carried out showing the minimum defect size which can be identify reliably. This allows designing a reliable structural health monitoring system based on guided electromagnetic waves trapped in the tunnel.

Wither now the Design Building Block (DBB) Approach

A description of the Design Building Block approach (DBB) was first published at IMDC1997, followed by a practical realisation presented at IMDC2003, both emphasised 3D as a key element of dialogue and creativity in early ship design. The current article celebrates, at the 15th IMDC, this architecturally driven ship synthesis approach with an overview of its fundamentals, followed by a suggestion for an open, collaborative and web-based implementation, and then provides examples that can be used when teaching the approach in ship design. The paper’s first part covers the basics of this UCL-developed method, with an overview of the processes, terminology, flow of ship design information, key analyses and key examples published in the literature. The second part focus on an initial attempt to compile a version of this method that can be adapted and implemented in other academic environments, outside the original scope, which was focused on the early stage design of a range of innovative naval vessels. This part of the paper includes an extension of the current taxonomy to commercial vessels, as well as an adapted approach that can be used for ship design teaching and research. Additionally, a compilation of open online stepwise examples is presented, using the NTNU-developed web-based library Vessel.js. These examples cover the basic steps to teach the use of and to readily modify DBB for environments outside the constraints more applicable to multirole naval vessels. The paper concludes with a summary of its main intentions, emphasising the current gap that it is seen to fulfil by compiling the key DBB derived information in a single document. This is then followed by open and online examples that can be readily accessed, modified and expanded.

Digital Transformation and Public Administration: The Impacts of India’s Digital Public Infrastructure

ABSTRACT Over the past decades, digital technologies have become ubiquitous, impacting and changing the ways society operates. Immense public and economic value is being created by improving access to information and resources. Hence, many public administration units around the globe continue to focus on digital transformation. Although mostly associated with digitizing services and workflow via software platforms, India’s efforts have taken a “Lego building block approach” toward technology which can be repurposed and recombined to deliver solutions at the social level. These digital public infrastructure (DPI) blocks have had significant impact on socio-economic development. In this special issue, we explore the role of DPI in digitally transforming public service delivery and in creating public value. The issue aims to make an important contribution to public administration and digital government literature, by examining India’s DPI and its positive externalities, in particular its role in financial and health inclusion. These papers include vital knowledge that can support policy processes on digital transformation and public value creation for India and other developing countries of the global South.

Virtual Full Scale Static Test of a Civil Tilt Rotor Composite Wing in Non-Linear Regime

This study addresses the crucial role of post-buckling behavior analysis in the structural design of composite aeronautical structures. Traditional engineering practices tend to result in oversized composite components, increasing structural weight. EASA AMC 20-29’s Building Block Approach suggests phased testing, but its time and cost challenges necessitate a shift to high-fidelity post-buckling analyses, exemplified by MSC NASTRAN SOL 400. This approach, showcased in the analysis of the Next Generation Civil Tilt Rotor Technology Demonstrator’s wing (NGTCTR-TD), effectively de-risks static tests, contributing to a more efficient certification process. The study demonstrates how advanced simulations provide detailed insights into local buckling phenomena, allowing precise stress distribution analysis. These analyses eliminate the risk of structural failure, paving the way for safer, more efficient, and cost-effective airframe structures. Future developments aim to validate numerical analyses with experimental data, further emphasizing the reliability and benefits of high-fidelity simulations.

Amplifying weak signals: a method-building approach for inclusive climate resilience strategy making

Socio-ecological inclusion and the impacts of climate change on the built environment are two shared concerns central to the design and planning of the just transition in cities. The just transition leans heavily on inclusive convergence processes that are grounded in knowledge integration and transdisciplinary practice. However, there is a paucity of effective methods for the inclusion of so-called weak signals from actors situated at the periphery of these convergence processes. Building on the concept of structured flexibility, we introduce a building-blocks approach as a modular architecture for constructing methods for distributed engagement and knowledge integration beyond conventional small-group settings. By engaging in research through design, the Amplifying Weak Signals approach was prototyped with students in the context of dealing with heatwaves in The Hague and tested with expert users from the region who facilitate resilience strategy-making processes. Out of 900 possible building block combinations, 18 methods were created during prototyping. The resulting heatwave strategies that were drafted based on the collected peripheral knowledge showed the integration of new socio-ecological issues rather than a drastic departure from the baseline resilience strategy of the city. We discuss the research findings and their use in the production of guidelines for the construction of methods to integrate peripheral knowledge in convergence processes. Ongoing work to develop the guidelines in the form of an open-access, interactive repository of knowledge elicitation methods for urban resilience spatial planning will also be described. Recommendations for scaling the approach are provided.

Facile one-step preparation of Co2CrO4 spinel from heterometallic compounds – Structural, magnetic, electrical and photocatalytic studies

Two isostructural heterometallic complex salts with mononuclear units, [NH(CH3)2(C2H5)][Cr(terpy)2][CoCl4]2 (1) and [NH(CH3)(C2H5)2][Cr(terpy)2][CoCl4]2 (2), were synthesized using a building block approach and characterized by single-crystal and powder X-ray diffraction (XRD), impedance spectroscopy and magnetization measurements. They exhibit particular humidity-sensing properties and very high proton conductivity at room temperature. The magnetization of complexes shows the high spin state of 3/2 for tetrahedrally coordinated CoII ions, which on cooling remain in the paramagnetic state within the CrIII network, which is antiferromagnetically correlated. The prepared compounds were thoroughly explored as single-source precursors for the formation of the spinel oxide Co2CrO4 by their thermal decomposition. By optimizing the annealing temperature, heating/cooling rates and holding times, the phase composition of thermal processing of 1 or 2 was evaluated: phase pure spinel Co2CrO4 was obtained by thermal treatment already at 450 °C. The structure, morphology, and optical properties of spinel oxides prepared at different temperatures were characterized using powder XRD, field emission scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), while electrical and magnetic by impedance spectroscopy and magnetization measurements. The determined band gap energy and nanosized crystallites prompted us to investigate the photocatalytic activity of spinel oxide produced at 450 °C in the degradation of dyes Rhodamine B (RhB) and Methylene blue (MB) under Vis irradiation without and with assistance of hydrogen peroxide (H2O2). The results show that the Co2CrO4/H2O2 system exhibits a significantly higher photoactivity response; the degradation efficiency of MB and RhB was found to be 86.1% and 80.3%, respectively. The electrical conductivity spectra and the activation energy for the DC conductivity demonstrate the electronically semiconducting behaviour of the Co2CrO4 oxide. The Co2CrO4 spinel has a ferrimagnetic ground state, with mixed CoII and CoIII ions on the tetrahedral and octahedral sites: CoII having a high spin state on both sites and CoIII having a high spin state on the tetrahedral site and a low spin state on the octahedral site. Different thermal treatments affect the magnetization according to the different sizes of the obtained crystallites.

A Building Blocks Approach to Implementing a Telehealth Clinic Model to Improve Primary Care Access in the Philippines: A Large-scale Pilot Project

A limited number of healthcare workers and cost constraints limit primary care access in the Philippines. To test telehealth as a low-cost and effective solution, a large-scale digital health clinic was implemented in the selected urban and rural communities. In collaboration with local authorities, our pilot telemedicine clinic was implemented for 3 days in January 2023. Patients were registered and their vitals were assessed before they were seen by a remote United States-based licensed physician who provided recommendations for treatment. Medical devices with real-time streaming capabilities, such as electronic stethoscopes, were utilized to enhance remote examinations. A total of 322 patients were treated at the telehealth clinic, of which 218 completed a population health survey. A large proportion of patients had a doctor visit more than 12 months prior (39.2%) and had not received a dental examination (86.3%) or an eye examination within the past year (84.4%). Most patients had access to a smartphone (69.7%). A lower proportion had access to an internet connection that was sufficient for video calls (57.9%) or a laptop (8.5%). Our clinic demonstrated that telehealth is a feasible solution to improve primary care access for disadvantaged communities in the Philippines.

Testing Structural Elements under Multiaxial Loading: A Numerical Model of the Bench to Understand and Predict Complex Boundary Conditions

Airworthiness certification requires proof of structure strength, which is performed generally through a building block approach. To achieve this, representative intermediate-scale experiments generated by test benches are, in general, needed, in addition to material characterization on a coupons scale and structure testing on a large scale. The VERTEX test bench can generate the combined loading of tension/compression-shear-pressure on structural elements and was modelled with Finite Elements to perform virtual testing, representative of its intermediate-scale specificity. The numerous bolted joints of the bench were modelled and their behavior was identified in previous tests, so the model could quantitatively estimate the transfer function of the bench, which is the relationship between the displacements imposed by the jacks and the resulting loads on a given sample. The VERTEX model was identified to represent load shapes and amplitudes based on a training set and was later confronted by a validation set of tests of tension and shear. A model with ideal boundary conditions was also developed for a comparison, but it failed to predict some load shape specificities and did not give any indication of the loading amplitude. Application cases of the developed model are shown to assess a range of virtual testing possibilities.

A Building Block Approach to Retirement Income Design

A Building Block Approach to Retirement Income Design

Collisions between Drones and Rotorcraft: Modeling of the Crash Response of Battery Packs

Drones operating in an urban environment pose a potential collision threat to rotorcraft. In this paper, the battery pack of the DJI MAVIC 2 ZOOM is analyzed since the battery is considered to be the greatest threat due to its high weight and stiffness. Following a pyramid-type building block approach, a high-fidelity model simulation was developed for LSDYNA based on a wide range of experiments, ranging from quasi-static material tests to quasi-static component tests up to high-velocity impact experiments. The high-fidelity model allows the prediction of damage in potential collision scenarios between a high-speed rotorcraft and the battery pack of the drone. For the particular impact configuration analyzed within this paper, the drone battery does not cause catastrophic failure of the windshield of the rotorcraft.

Building-block approach to discrete and sequence-specific oligosiloxanes

Four 26-mers with molecular weights of 3431.78 with different sequences (AB, AABB, AAABBB, and AAAABBBB) are precisely synthesized on a gram scale.

Preparation of silyl-functionalized double six-ring (D6R) siloxanes and unique assembly by hydrogen bonding of silanol groups

Abstract Cage-type silicate with a double six-ring (D6R) structure is successfully functionalized with dimethylsilyl and dimethylsilanol groups. The dimethylsilanol-functionalized cages are assembled to form a 1D structure through intermolecular hydrogen bonding of the silanol groups between the cages. These results will contribute to the development of a building-block approach for the creation of ordered siloxane-based nanomaterials.