Modular Strategy Research Articles

“Boron Ylide” Enables Stereoselective Construction of gem‐Diborylcyclopropanes

AbstractThe stereoselective cyclopropanation of olefins with “boron ylide” is disclosed for the first time, providing a modular strategy for the synthesis of stereospecific diboryl‐functionalized cyclopropanes. The chiral gem‐diborylcyclopropanes are synthesized with excellent enantioselectivity with the aid of a chiral auxiliary. Based on the powerful transformable ability of boryl group, those challenging multi‐quaternary carbon centers in cyclopropane units have been facilely constructed with excellent stereoselectivity. Control experiments indicate that the boryl groups are necessary for both chemoselectivity and stereoselectivity control.

"Boron Ylide" Enables Stereoselective Construction of gem-Diborylcyclopropanes.

The stereoselective cyclopropanation of olefins with "boron ylide" is disclosed for the first time, providing a modular strategy for the synthesis of stereospecific diboryl-functionalized cyclopropanes. The chiral gem-diborylcyclopropanes are synthesized with excellent enantioselectivity with the aid of a chiral auxiliary. Based on the powerful transformable ability of boryl group, those challenging multi-quaternary carbon centers in cyclopropane units have been facilely constructed with excellent stereoselectivity. Control experiments indicate that the boryl groups are necessary for both chemoselectivity and stereoselectivity control.

Optimizing economic feasibility of CO2 capture processes with rotating packed bed (RPB): Strategies for scale and modularization

Rotating Packed Bed (RPB) technology is increasingly recognized in the field of carbon capture for its potential to broaden application scopes and significantly reduce capital expenditures by minimizing packing volume. However, the commercialization of RPB-based CO2 capture presents several challenges at the process level, including enhancing energy efficiency, refining equipment design, and achieving scalability. Given the mechanical constraints, designing excessively large RPB units may be impractical. Thus, the economic scalability of RPB-based CO2 capture under practical constraints remains an unresolved issue. This study explores the cost-optimal CO2 capture scale through rigorous process simulation using 30-70 wt% monoethanolamine (MEA) solvents. It optimizes the process design and operating parameters to minimize the specific CO2 avoidance costs, within the bounds of practical RPB design limitations. The findings suggest that a capture scale of 100–200 Tons Per Day (TPD) is cost-optimal when using 50 wt% MEA for flue gases with CO2 concentrations above 14.5 mol%. However, cost-effective RPB design becomes challenging at CO2 concentrations as low as 4 mol%. The analysis suggests that the optimal scale might increase with future advancements in RPB design technologies. Current design constraints necessitate a modular approach as the most economically viable strategy for scaling up RPB-based CO2 capture. This modularization strategy supports the wider adoption of CO2 capture technologies at small- to medium-scales, facilitating industry-wide implementation and sustainable progress by reducing initial investment and allowing for phased scaling.

General and Modular Synthesis of Covalent Organic Cages for Efficient Molecular Recognition.

Cage-type structures based on coordination and dynamic covalent chemistry have the characteristics of facile and efficient preparation but poor stability. Chemically stable organic cages, generally involving fragment coupling and multi-step reactions, are relatively difficult to synthesize. Herein, we offer a general and modular strategy to customize covalent organic cages with diverse skeletons and sizes. First, one skeleton (S) module with three extension (E) modules and three reaction (R) modules are connected by one- or two-step coupling to get the triangular monomer bearing three reaction sites. Then one-pot Friedel-Crafts condensation of the monomer and linking module of paraformaldehyde produces the designed organic cages. The cage forming could be regulated by the geometrical configuration of monomeric blocks. The S-E-R angles in the monomer is crucial; only 120° (2,4-dimethoxyphen as reaction module) or 60° (2,5-dimethoxyphen as reaction module) angle between S-E-R successfully affords the resulting cages. By the rational design of the three modules, a series of organic cages have been constructed. In addition, the host-guest properties show that the representative cages could strongly encapsulate neutral aromatic diimide guests driven by solvophobic interactions in polar solvents, giving the highest association constant of (2.58±0.18)×105 M-1.

General and Modular Synthesis of Covalent Organic Cages for Efficient Molecular Recognition

AbstractCage‐type structures based on coordination and dynamic covalent chemistry have the characteristics of facile and efficient preparation but poor stability. Chemically stable organic cages, generally involving fragment coupling and multi‐step reactions, are relatively difficult to synthesize. Herein, we offer a general and modular strategy to customize covalent organic cages with diverse skeletons and sizes. First, one skeleton (S) module with three extension (E) modules and three reaction (R) modules are connected by one‐ or two‐step coupling to get the triangular monomer bearing three reaction sites. Then one‐pot Friedel‐Crafts condensation of the monomer and linking module of paraformaldehyde produces the designed organic cages. The cage forming could be regulated by the geometrical configuration of monomeric blocks. The S−E−R angles in the monomer is crucial; only 120° (2,4‐dimethoxyphen as reaction module) or 60° (2,5‐dimethoxyphen as reaction module) angle between S−E−R successfully affords the resulting cages. By the rational design of the three modules, a series of organic cages have been constructed. In addition, the host‐guest properties show that the representative cages could strongly encapsulate neutral aromatic diimide guests driven by solvophobic interactions in polar solvents, giving the highest association constant of (2.58±0.18)×105 M−1.

Valorization of Eggshell as Renewable Materials for Sustainable Biocomposite Adsorbents—An Overview

The production and buildup of eggshell waste represents a challenge and an opportunity. The challenge is that uncontrolled disposal of generated eggshell waste relates to a sustainability concern for the environment. The opportunity relates to utilization of this biomass resource via recycling for waste valorization, cleaner production, and development of a circular economy. This review explores the development of eggshell powder (ESP) from eggshell waste and a coverage of various ESP composite sorbents with an emphasis on their potential utility as adsorbent materials for model pollutants in solid–liquid systems. An overview of literature since 2014 outlines the development of eggshell powder (ESP) and ESP composite adsorbents for solid–liquid adsorption processes. The isolation and treatment of ESP in its pristine or modified forms by various thermal or chemical treatments, along with the preparation of ESP biocomposites is described. An overview of the physico-chemical characterization of ESP and its biocomposites include an assessment of the adsorption properties with various model pollutants (cations, anions, and organic dyes). A coverage of equilibrium and kinetic adsorption isotherm models is provided, along with relevant thermodynamic parameters that govern the adsorption process for ESP-based adsorbents. This review reveals that ESP biocomposite adsorbents represent an emerging class of sustainable materials with tailored properties via modular synthetic strategies. This review will serve to encourage the recycling and utilization of eggshell biomass waste and its valorization as potential adsorbent systems. The impact of such ESP biosorbents cover a diverse range of adsorption-based applications from environmental remediation to slow-release fertilizer carrier systems in agricultural production.

SMT2Test: From SMT Formulas to Effective Test Cases

One of the primary challenges in software testing is generating high-quality test inputs and obtaining corresponding test oracles. This paper introduces a novel methodology to mitigate this challenge in testing program verifiers by employing SMT (Satisfiability Modulo Theories) formulas as a universal test case generator. The key idea is to transform SMT formulas into programs and link the satisfiability of the formulas with the safety property of the programs, allowing the satisfiability of the formulas to act as a test oracle for program verifiers. This method was implemented as a framework named SMT2Test, which enables the transformation of SMT formulas into Dafny and C programs. An intermediate representation was designed to augment the flexibility of this framework, streamlining the transformation for other programming languages and fostering modular transformation strategies. We evaluated the effectiveness of SMT2Test by finding defects in two program verifiers: the Dafny verifier and CPAchecker. Utilizing the SMT2Test framework with the SMT formulas from the SMT competition and SMT solver fuzzers, we discovered and reported a total of 14 previously unknown defects in these program verifiers that were not found by previous methods. After reporting, all of them have been confirmed, and 6 defects have been fixed. These findings show the effectiveness of our method and imply its potential application in testing other programming language infrastructures.

Accessing polyarene-fused ten-membered lactams via oxidative N-heterocyclic carbene (NHC)-catalyzed high-order [7 + 3] annulation

A new oxidative N-heterocyclic carbene (NHC)-catalyzed high-order [7 + 3] annulation reaction of γ-indolyl phenols as 1,7-dinucleophiles and α,β‐alkynals with the aid of Sc(OTf)3 is reported, enabling the highly regioselective access to unprecedented polyarene-fused ten-membered lactams bearing a bridged aryl-aryl-indole scaffold in moderate to good yields. This protocol demonstrates a broad substrate scope, good compatibility with substituents and complete regioselectivity, providing an organocatalytic modular synthetic strategy for creating medium-sized lactams.

Flexible modular strategy for tailored, human–machine fusion wearable electronics

Over the past three decades, the field of wearable electronics has experienced significant growth, with future developments expected to lead to more seamless integration and a profound symbiosis between humans and electronic systems. However, current developments in wearable technology are constrained by traditional integrated circuit (IC) design paradigms and a limited range of form factors, predominantly manifesting as watches, glasses, and rings with fixed functionalities and performance capabilities. This study proposes a modular design method that leverages flexible electronics for tailoring wearable devices according to specific needs. This approach disperses and reinterprets the integrated device forms through the guidance of human body morphology and conformal design principles. The functional units within these wearable devices are constructed as physically isolated, flexible modules within a robust bus structure. These modules can be easily integrated using magnetic attachments and connectors, which allows for the creation of unconventional wearable devices with customised functionalities and forms. To validate this approach, a series of flexible functional modules were designed and prototyped. Demonstrations of some of these integrated wearable forms, including watches, headbands, and gloves, highlight the versatility of this approach. These devices can be rapidly assembled with selected flexible modules capable of monitoring vital signs, such as heart rate, peripheral capillary oxygen saturation (SpO2), barometric pressure, humidity, and temperature. The results suggest that the proposed modular method holds significant potential for advancing the development of future human–machine fusion wearable electronics.

Power battery modular innovation investment strategies with government subsidy policies

This paper investigates the closed-loop supply chain decisions of battery manufacturers considering innovation investments and different subsidy methods provided by the government. The analysis encompasses four scenarios: whether battery manufacturers engage in innovation investments and whether the government opts for technology R&D subsidies or production subsidies. The study finds that innovation investments by battery manufacturers can enhance the modularization level of batteries. The reward or penalty measures for recycling quality imposed on automobile manufacturers elevate the quality of battery recycling, and also increase the wholesale price of batteries and the retail price of automobiles. After implementing R&D and production subsidies, both the modularization level of batteries and the profits of supply chain members exceed those without subsidies, though these subsidies do not affect the quality of battery recycling. R&D subsidies more effectively promote innovation capacity and product quality among battery manufacturers, whereas production subsidies more significantly boost the profits of both battery manufacturers and automobile manufacturers. Therefore, subsidy measures should be tailored according to different stages of the power battery industry's development. Regardless of whether battery manufacturers invest in innovation or whether the government provides subsidies, collaboration between battery manufacturers and automobile manufacturers is essential to coordinate the closed-loop supply chain. The research findings offer valuable guidance for formulating subsidy policies in the new energy vehicle industry across different periods, and also provide theoretical insights for decision-making behaviors among related enterprises.

Electrochemical Halogenation of Naphthoquinones: A Modular and Sustainable Strategy towards Trypanocidal Compounds.

An eco-friendly electrochemical halogenation of 2-amino-1,4-naphthoquinones has been developed. The new mild and energy efficient methodology comprises sustainable features like oxidant free and double role of the halogen source as electrolyte, originating twenty-six amino-halogenated naphthoquinoidal derivatives in good yields under mild conditions. This novel methodology permitted access to new potent trypanocidal prototypes, where six compounds were more active than benznidazole, the current market drug used in the treatment of Chagas Disease.

Superior Circularly Polarized Luminescence Brightness Achieved with Chiral Heteroleptic Nine-Coordinate Coumarin-Based Tb3+ Complexes.

In order to facilitate the practical application of circularly polarized luminescence (CPL) active molecules, the CPL brightness (BCPL) must be optimized. We have applied a binary modular strategy to synthesize two chiral organo-Tb3+ complexes, [Tb(Coum)3(1R,2R-Ph-PyBox)] (2) and [Tb(Coum)3(1S,2S-Ph-PyBox)] (5), combining 3-acetyl-4-hydroxy-coumarin (Coum) and enantiopure 2,6-bis(4-phenyl-2-oxazolin-2-yl) pyridine (1R,2R/1S,2S-Ph-PyBox). The photophysical properties of these novel complexes have been fully characterized. The combined point-chiral induction capability of chiral bis(oxazoline) derivatives and the outstanding photophysical properties of the coumarin-derived ligand have resulted in an intense excited-state chiroptical activity (|glum| = 0.097-0.103) for both Tb3+ enantiomers, with a bright Tb3+-centered high-purity green emission (ΦPL = 74%) and enhanced antenna-centered absorption behavior (ε320nm = 47820-47940 M-1 cm-1). A superior BCPL (1132.7-1205.8 M-1 cm-1 at 5D4 → 7F5) has been established for complexes 2 and 5. The strategy adopted in this work provides a new route to chiroptical organo-Tb3+ luminophores with outstanding comprehensive performance.

Proving Confluence in the Confluence Framework with CONFident

This article describes the confluence framework, a novel framework for proving and disproving confluence using a divide-and-conquer modular strategy, and its implementation in CONFident. Using this approach, we are able to automatically prove and disprove confluence of Generalized Term Rewriting Systems, where (i) only selected arguments of function symbols can be rewritten and (ii) a rather general class of conditional rules can be used. This includes, as particular cases, several variants of rewrite systems such as (context-sensitive) term rewriting systems, string rewriting systems, and (context-sensitive) conditional term rewriting systems. The divide-and-conquer modular strategy allows us to combine in a proof tree different techniques for proving confluence, including modular decompositions, checking joinability of (conditional) critical and variable pairs, transformations, etc., and auxiliary tasks required by them, e.g., joinability of terms, joinability of conditional pairs, etc.

A Modular Biosensor Design for Quantitative Measurement of Free Nedd8.

The objective of our study was to develop a genetically encoded biosensor for quantification of Nedd8, a post-translational modifier that regulates cellular signals through conjugation to other proteins. Perturbations in the balance of free (i.e., unconjugated) and conjugated Nedd8 caused by defects in Nedd8 enzymes or cellular stress are implicated in various diseases. Despite the biological and biomedical importance of Nedd8 dynamics, no method exists for direct quantification of free Nedd8, hindering the study of Nedd8 and activities of its associated enzymes. Genetically encoded biosensors are established as tools to study other dynamic systems, but limitations of current biosensor design methods make them poorly suited for free Nedd8 quantification. We have developed a modular method to design genetically encoded biosensors that employs a target binding domain and two reporter domains positioned on opposite sides of the target binding site. Target quantification is based on competition between target binding and the interaction of the reporter domains. We applied our design strategy to free Nedd8 quantification by developing a selective binder for free Nedd8 and combining it with fluorescent or split nanoluciferase reporters. Our sensors produced quantifiable and specific signals for free Nedd8 and enabled real-time monitoring of deneddylation by DEN1 with a physiological substrate. Our sensor design will be useful for high-throughput screening for deneddylation inhibitors, which have potential in treatment of cancers such as acute lymphoblastic leukemia. The modular design strategy can be extended to develop genetically encoded quantitative biosensors for other proteins of interest.

Versatile, Modular, and General Strategy for the Synthesis of α-Amino Carbonyls.

Modulating the basicity of alkylamines is a crucial factor in drug design. Consequently, alkylamines with a proximal amide, ester, or ketone have become privileged features in many pharmaceutical candidates. The impact of α-amino carbonyls has made the development of new methods for their preparation a continuous challenge in synthesis. Here, we describe a practical strategy that provides a modular and programmable synthesis of a wide range of α-amino carbonyls. The generality of this process is made possible by an extremely mild method to generate carbamoyl radicals, proceeding via a Lewis acid-visible-light-mediated Norrish type-I fragmentation of a tailored carboxamide reagent and intercepted through addition to in situ generated unbiased imines. Aside from the reaction's broad scope in each component, its capacity to draw on plentiful and diversely populated amine and carbonyl feedstocks is showcased through a two-dimensional array synthesis that is used to construct a library of novel, assay-ready, α-amino amides.

The Total Synthesis of Hyperfirin via a Cyclooctadiene Strategy.

Polycyclic polyprenylated acylphloroglucinols (PPAPs) combine compelling structural complexity with effective biological activity. The total synthesis of Hyperfirin is reported as one linear sequence. Key to this novel modular strategy is to access the bicyclo[3.3.1]nonane-2,4,9-trione framework via transannular acylation of a decorated eight-membered ring, followed by late stage bridgehead substitution. The described route adds flexibility to PPAP construction and broadens the scope of eight-membered ring chemistry.

A Modular Three-Component Approach for Site-selective Tandem Arene Thiophosphorylation.

Thiophosphates serve as pivotal reagents within the realms of both organic and inorganic synthesis, with their most notable applications observed in agricultural chemistry. This manuscript delineates a modular three-component synthetic strategy for site-selective arene C-H thiophosphorylation with thianthrenium salt, 1,4-diazabicyclo[2.2.2]octane-sulfur dioxide (DABSO), and diarylphosphine oxides as substrates. This approach facilitates the metal-free and green synthesis of a diverse spectrum of S-aryl phosphorothioates through C-H functionalization and late-stage modification showcasing practicality and broad applicability.

Modularity and new product performance: the role of new product development speed and task uncertainty

Similar to the advantages of product modularity to a firm’s overall performance, new product modularity could provide advantages to the new product development process and result in its success in the marketplace. Accordingly, this study investigates the effect of new product modularity on its financial and market-related performance (new product performance). To identify processes underlying this effect, NPD speed and task uncertainty have been considered as its mediator and moderator, respectively. In this vein, survey data from 190 Iranian manufacturing firms have been gathered and research hypotheses have been examined using structural equation modelling and bootstrapping approach. The results of this study reveal that new product modularity improves NPD speed and new product performance. Additionally, NPD speed is found to have a partial mediating role between new product modularity and performance. Finally, this study empirically shows that the positive effect of new product modularity on new product performance amplifies in tasks marked by heightened uncertainty. The findings of the current study highlight the determinant role of modular strategy and NPD speed in developing successful new products.

Reduced Order Generalized Integrator Based Modular Multilevel Converter Loop Current Suppression Strategy under Unbalanced Conditions in Distribution Networks

Under the condition of grid voltage imbalance, the circulation of the bridge arm inside the modular multilevel converter (MMC) increases significantly, which leads to the aggravation of the distortion of the bridge arm current, and, thus, increases the system loss and reduces the power quality. To address this problem, this paper analyzes the mechanism of circulating current generation and proposes a circulating current suppression strategy based on a reduced-order generalized integrator (ROGI), which firstly uses the ROGI system to separate the second-harmonic positive- and negative-sequence components in the circulating current from the DC, and then converts the rotating coordinates of the circulating current’s second octave component into the DC to be fed into the proportional–integral quasi-resonance (PIR) controller for suppression. A simulation model of a 23-level MMC inverter is built in MATLAB/Simulink, and the control strategy proposed in this paper is compared with the classical proportional–integral (PI) control in simulation experiments. The simulation results show that the amplitude of the circulating current fluctuation of the classical PI control is reduced from 90 A to 22 A, and the harmonic distortion rate of the bridge arm current is reduced from 32.56% to 5.57%; the amplitude of the circulating current fluctuation of the control strategy proposed in this paper is reduced from 90 A to 5.7 A, and the harmonic distortion rate of the bridge arm current is reduced from 20.2% to 1.13%, which verifies the effectiveness of the pro-posed control strategy.

Cobalt(II)-Catalyzed Proficient Synthesis of Enaminones from Aryl Alkenes and Amines

AbstractA simple, cost-effective, and modular strategy has been developed to synthesize synthetically and pharmaceutically active enaminones by oxidative amination of aryl alkenes with amines and CHCl3, using tert-butyl hydroperoxide as an oxidant. We describe the synthesis of enaminones from vinyl arenes and sterically hindered N,N-diisopropylethylamine (DIPEA) by employing an Earth-abundant cobalt salt as a catalyst within a very short reaction period for the first time. Furthermore, nitrogen- and oxygen-containing heterocyclic compounds have been synthesized from these highly functionalized enaminones. Moreover, various control experiments, such as radical trapping reaction, along with a Hammett analysis with various types of substituents on the styrene ring unraveled the detailed mechanism of this reaction pathway.