Chain Mechanism Research Articles

Radical Dearomatising Spirocyclisation of Benzisoxazole‐Tethered Ynones

AbstractThe dearomative spirocyclisation of benzisoxazoles through a radical chain mechanism is described. Densely functionalised spirocycles were prepared in high yields by reacting benzisoxazole‐tethered ynones with aryl thiols in 1,2‐dichloroethane (DCE) at 60 °C. The identification of stabilising three‐electron interactions was key to the development of this new radical cascade reaction. The obtained spirocyclic products were converted into other spirocyclic scaffolds through a two‐step hydrogenolysis‐cyclisation sequence.

Formation mechanism and quantitative risk analysis of the landslide-induced hazard chain by an integrated approach for emergency management: A case study in the Bailong River basin, China

The landslide–debris flow–river blockage hazard chain is one of the most common types of geological hazard chain in mountainous areas, seriously threatening human life and property across an extensive geographical area. The development of approaches for the rapid investigation and prediction of multi-hazard chains can play a significant role in reducing the number of casualties and economic losses. Here, taking the Lijie landslide–debris flow–river blockage in the Bailong River basin as a case study, we used remote sensing methods, geophysical technology, numerical simulations and empirical formulas to develop an integrated approach for analyzing the mechanisms, multi-hazard prediction and quantitative risk assessment induced by this geological hazard chain. The reactivation process of the Lijie landslide is composite retrogressive sliding. The steep slopes and highly fractured bedrock with low strength are the principal internal factors, and heavy rainfall in 2020 and spring freeze–thaw effect are the principal triggering factors. The deposited landslide material is eroded and transformed into a channel-type debris flow under high rainfall conditions. The steep terrain and abundant fine-grained material provides favorable conditions for a viscous debris flow with a long runout, which is usually followed by secondary disasters associated with river blockage. Our results indicate that under rainfall conditions with a 100-year return period, the Bailong river will be completely blocked by the landslide-induced debris flow. And there will be an estimated 5.84 million CNY of economic losses caused by the multi-hazard chain, which is 2.6 times the losses directly caused by the landslide. Our integrated approach is practicable in an emergency context and useful for local administrators to rapidly develop strategies for multi-hazard chain prevention and mitigation, based on information about the transformation mechanisms of the multi-hazard chain, potential hazard-affected areas, damaged degree of elements at the risk, and incurred economic losses.

Linking Effectuation Logic with Business Model Innovation: An Investigation in the Context of Swiss Startups

Over the last decades, business model innovation and effectuation have been widely discussed in the literature. While effectuation represents a behavioural approach for entrepreneurs using available means for founding a start-up, business model innovation represents an approach to creating a business model with long-term competitive advantages. Designing a business model requires to focus on four dimensions: customer, value proposition, value chain and revenue mechanism. A business model innovation is referred to when an innovative characteristic can be attributed to two of the four dimensions. Both effectuation and business model innovation are valuable for entrepreneurs who are pursuing growth in dynamic and uncertain business environments. This paper elaborates on effectuation and its potential effects on business model innovation. The addressed research questions are: Is the effectuation logic a facilitating aspect of business model innovation? And to what extent do entrepreneurs apply effectuation logic and design innovative business models? The underlying data consists of business plans of 25 finalists of a Swiss innovation competition with more than 100 startups from different business sectors every year. First, the chosen sample is reviewed on the extent of the application of effectuation based on selected behavioural criteria. Second, the sample is analysed for evidence of business model innovation based on the above-mentioned business model dimensions and their innovative potential. Third, the link between the two approaches is highlighted to gain insights into the potential influence of the applied decision logic to develop innovative business models, thus providing an understanding of how entrepreneurs could leverage the advantages of effectuation in the context of innovating the business model. Further research will focus on examining critical success factors of entrepreneurial behaviour in the applied business model types and their correlations with business performance.

Photochemical Oximesulfonylation of Alkenes Using Sulfonyl-oxime-ethers as Bifunctional Reagents.

Utilization of oxime ethers as bifunctional reagents remains unknown. Herein, we present a mechanistically distinct strategy that enables oximesulfonylation of olefins using sulfonyl-oxime-ethers as bifunctional reagents under metal-free photochemical conditions. Via concomitant C-S and C-C bond formation, the process permits incorporation of oxime and sulfonyl groups into olefins in a complete atom-economic fashion, providing rapid access to multi-functionalized β-sulfonyl oxime ethers with good yields and stereoselectivity. The method is amenable to functionalization of complex bioactive molecules and is shown to be scalable. A radical chain mechanism initiated via photochemical Hydrogen Atom Transfer (HAT) mediated N-O bond cleavage is suggested for the process, based on our results on mechanistic investigations.

Evolution law and transformation mechanism of force chains in the flow of photoelastic particles under a flexible barrier

The essence of large deformation flow in loose geological bodies lies in the breaking and rebuilding of force chains at the microscopic scale. Therefore, it is crucial to investigate force chains during particle flow processes. This study focuses on particle flow during the ore drawing process, develops a photoelastic experiment model, investigates the evolution law of force chains, reveals the transformation mechanism of strong and weak force chains, and provides insights for removing particle blockage in mining engineering. The results show that strong force chains are primarily located on both sides of the model, with fewer numbers, and extend toward the side boundaries in a direction close to 70°. Weak force chains are predominantly distributed in the middle section of the model, with numerous and uniformly developed directions. In addition, under the effects of self-organization and hetero-organization, the particles' sliding and rolling cause the buckling of force chains and the rearrangement of particles, resulting in the transformation between strong and weak force chains and accelerating the particles' flow. The research results deepen the understanding of the granular material large deformation flow-slip problem and provide a reference for similar engineering analyses.

Direct and Catalyst-Free Ester Metathesis Reaction for Covalent Adaptable Networks.

Thermosetting polymers possess excellent environmental resistance and mechanical properties but cannot be reprocessed due to their covalently cross-linked structures. Recycling of thermosets via the implantation of dynamic covalent bonds offers a promising solution. Here, we report the direct and catalyst-free ester metathesis of N-acyloxyphthalimide (NAPI) at about 100 °C without the requirement of hydroxyl groups and its utilization for the fabrication of covalent adaptable networks (CANs). NAPI metathesis has interesting sigmoid kinetics with a fast exchange rate, which proceeds via a free radical chain mechanism, guaranteeing a fast associative exchange under a rather low dissociation. The bifunctional molecule of NAPI as both the radical precursor and substrate is the key to the dissociatively initiated associative (DAssociative) mechanism and kinetic behavior. Based on the efficient NAPI metathesis, polyester networks, poly(N-acyloxyphthalimides) (PNAPIs), show excellent malleability. Notably, PNAPIs exhibit exceptional solvent resistance and mechanical stability at elevated temperatures owing to the unique DAssociative mechanism, suggesting exciting opportunities for designing recyclable thermosetting polymers.

Unraveling the 2021 Central Tennessee flood event using a hierarchical multi-model inundation modeling framework

Flood prediction systems need hierarchical atmospheric, hydrologic, and hydraulic models to predict rainfall, runoff, streamflow, and floodplain inundation. The accuracy of such systems depends on the error propagation through the modeling chain, sensitivity to input data, and choice of models. In this study, we used multiple precipitation forcings (hindcast and forecast) to drive hydrologic and hydrodynamic models to analyze the impacts of various drivers on the estimates of flood inundation depth and extent. We implement this framework to unravel the August 2021 extreme flooding event that occurred in Central Tennessee, USA. We used two radar-based quantitative precipitation estimates (STAGE4 and MRMS) as well as quantitative precipitation forecasts (QPF) from the National Weather Service Weather Prediction Center (WPC) to drive a series of models in the hierarchical framework, including the Variable Infiltration Capacity (VIC) land surface model, the Routing Application for Parallel Computation of Discharge (RAPID) river routing model, and the AutoRoute and TRITON inundation models. An evaluation with observed high-water marks demonstrates that the framework can reasonably simulate flood inundation. Despite the complex error propagation mechanism of the modeling chain, we show that inundation estimates are most sensitive to rainfall estimates. Most notably, QPF significantly underestimates flood magnitudes and inundations leading to unanticipated severe flooding for all stakeholders involved in the event. Finally, we discuss the implications of the hydrodynamic modeling framework for real-time flood forecasting.

Diastereoselective Construction of α‐Fluoroalkyl Cycloalkanols via Radical Alkylation of α‐Fluoroalkyl Ketones†

Comprehensive Summaryα‐Fluoroalkyl (Rf) alcohols are privileged motifs in drugs and pharmaceutically active compounds. As such, it is highly desirable to develop efficient methods for assembling these scaffolds. Herein, a visible‐light‐induced cascade radical cyclization of alkenyl fluoroalkyl ketones is developed, producing a variety of decorate α‐Rf cycloalkanols in promising yields with up to >20 : 1 dr selectivity. A radical chain mechanism involving an intramolecular radical addition to the α‐Rf carbonyl group and a subsequent intermolecular hydrogen atom transfer (HAT) has been proposed. Density functional theory (DFT) calculations indicate that a fluorine effect contributes to the radical addition to carbonyls by lowering the π* (C=O) orbital energy of CORf and energy barrier of the HAT between alkoxy radicals and THF, which may be valuable for controllable transformations of fluorinated molecules.

Exploring the risk propagation mechanisms of supply chain for prefabricated building projects

Prefabricated building (PB) is an innovative construction method with significant advantages in environmental protection, energy saving, productivity increase, and quality improvement. The complexity of the prefabricated building project supply chain (PBPSC) also induces risks leading to the failure of PBP. Existing researches consider risks isolated and ignores the interactions between stakeholders of PBPSC that can lead to risk propagation and management failures. This study integrated epidemic models with complex networks to explore risk propagation mechanisms in PBPSC. The hierarchical structure of PBPSC was transited into a complex network for analyzing the features of the risk propagation process and the risk propagation capacity of initial infection nodes. The analysis results indicated that risk propagation and risk recovery were medium and often overlooked, which caused risk propagation in PBPSC. When major PBP contractors and construction enterprises were affected by risks, risk propagation was more likely to occur in PBPSC. This study was a meaningful attempt to analyze the risk propagation mechanisms from the perspective of complex networks in PBPSC. Based on the analysis results, this study revealed the critical risks and propagation characteristics of PBPSC for exploring the risk propagation mechanisms and response strategies to improve the risk response capacity of PBPSC.

Photochemical Oximesulfonylation of Alkenes Using Sulfonyl‐oxime‐ethers as Bifunctional Reagents

Utilization of oxime ethers as bifunctional reagents remains unknown. Herein, we present a mechanistically distinct strategy that enables oximesulfonylation of olefins using sulfonyl‐oxime‐ethers as bifunctional reagents under metal‐free photochemical conditions. Via concomitant C‐S and C‐C bond formation, the process permits incorporation of oxime and sulfonyl groups into olefins in a complete atom‐economic fashion, providing rapid access to multi‐functionalized β‐sulfonyl oxime ethers with good yields and stereoselectivity. The method is amenable to functionalization of complex bioactive molecules and is shown to be scalable. A radical chain mechanism initiated via photochemical Hydrogen Atom Transfer (HAT) mediated N‐O bond cleavage is suggested for the process, based on our results on mechanistic investigations.

How has social media been affecting problem-solving in organizations undergoing Lean Production implementation? A multi-case study

This paper investigates the impact of social media utilization on problem-solving routines in organizations undergoing Lean Production (LP) implementation. A multi-case study was conducted in three firms from different sectors with distinct maturity levels of LP implementation. Empirical evidence was collected through complementary ways, such as semi-structured interviews, secondary data, and in loco non-participant observation. Data were then analyzed and triangulated, leading to propositions on the effects of social media on problem-solving activities in lean organizations. This research was grounded on the concepts of Information Manipulation Theory. Our findings suggest that, while social media may contribute to the amount of information that is shared for solving problems, the relevance and the level of details of such information may be shallow, overburdening the help chain mechanisms and generating wastes like overprocessing. The identification of the impact of social media on problem-solving activities enables a better comprehension of how new information and communication technologies can promote (or impair) the intra- and inter-organizational links. It also helps identify improvement opportunities in integrating social media into problem-solving routines, resulting in more responsive and competitive organizations.

Exploring the use of governance mechanisms in multi-tier sustainable supply chains

The extension of purchasing and supply chain management practices to reach upstream suppliers is critical in ensuring supply chain sustainability and requires the implementation of governance mechanisms. In this study, we investigate the mechanisms used by firms to ensure sustainability in multi-tier supply chains and how this use differs between the supply chain tiers. A multiple case study was conducted using semi-structured interview data from 25 companies covering three supply chain tiers. We identified 12 different governance mechanisms, the classification of which we suggest be based on their structure and purpose. While some differences were found regarding the specific practices used by individual firms, the overall findings indicate no major differences in terms of sustainability management efforts between the supply chain tiers. Thus, in contrast to previous studies, we show that lower-tier suppliers are active in the innovation and facilitation of supply chain sustainability. Also, the results confirm that firms often delegate the responsibility of ensuring sustainability to their direct suppliers.

The Effect of Plastic-Related Compounds on Transcriptome-Wide Gene Expression on CYP2C19-Overexpressing HepG2 Cells.

In recent years, plastic and especially microplastic in the oceans have caused huge problems to marine flora and fauna. Recently, such particles have also been detected in blood, breast milk, and placenta, underlining their ability to enter the human body, presumably via the food chain and other yet-unknown mechanisms. In addition, plastic contains plasticizers, antioxidants, or lubricants, whose impact on human health is also under investigation. At the cellular level, the most important enzymes involved in the metabolism of xenobiotic compounds are the cytochrome P450 monooxygenases (CYPs). Despite their extensive characterization in the maintenance of cellular balance, their interactions with plastic and related products are unexplored. In this study, the possible interactions between several plastic-related compounds and one of the most important cytochromes, CYP2C19, were analyzed. By applying virtual compound screening and molecular docking to more than 1000 commercially available plastic-related compounds, we identified candidates that are likely to interact with this protein. A growth inhibition assay confirmed their cytotoxic activity on a CYP2C19-transfected hepatic cell line. Subsequently, we studied the effect of the selected compounds on the transcriptome-wide gene expression level by conducting RNA sequencing. Three candidate molecules were identified, i.e., 2,2'-methylene bis(6-tert-butyl-4-methylphenol), 1,1-bis(3,5-di-tert-butyl-2-hydroxyphenyl) ethane, and 2,2'-methylene bis(6-cyclohexyl-4-methylphenol)), which bound with a high affinity to CYP2C19 in silico. They exerted a profound cytotoxicity in vitro and interacted with several metabolic pathways, of which the 'cholesterol biosynthesis process' was the most affected. In addition, other affected pathways involved mitosis, DNA replication, and inflammation, suggesting an increase in hepatotoxicity. These results indicate that plastic-related compounds could damage the liver by affecting several molecular pathways.

Reprocessible nanohybrid shish-kebab superstructures of poly (lactic acid) crystallites evolving in quiescent melt: Soft epitaxy nucleation in correlation with mechanics

Poly (butylene terephthalate) (PBT) nanofibrils (NFs) were developed in-situ by implementing a rheologically tuned melt spinning process on poly (lactic acid) (PLA)/PBT blends. In the absence of any flow fields, melt crystallization of fabricated PLA/PBT in-situ nanofibrillar composites (NFCs) resulted in orthogonal patterning of PLA nanodomain crystallites around single or double PBT NFs. Geometric confinement (soft epitaxy) was the nucleation mechanism of PLA chains at the interface of isotropic distributed PBT NFs followed by the formation of reprocessible 2D nanohybrid shish-kebab (NHSK) superstructures. By increasing the PBT NFs content and their bundling, a fan-shaped transcrystalline structure was formed due to seeding or epitaxial nucleation on the bundle of PBT NFs owning a less curved interface. The nucleation and growth mechanism of crystallites structures which were influenced by temperature and PBT NF content have been discussed thermodynamically and kinetically by parallel investigations on microscopic observations and X-ray diffraction analysis. The evolution of different crystalline structures in quiescent melt in the forms of spherulites, NHSK, or fan-shaped transcrystallinity induces a local orientation in the isotropic NFCs. Mechanical propertie improvements of NFCs were compared in amorphous and crystalline states with tailored NHSK superstructures.

Manipulation of the spacing between the donor and acceptor by gradual side-chain modification to reduce energy loss of the organic solar cells

As one of the simple but effective molecular modify strategies, the side chain engineering based on siloxane-terminated alkyl side chain has been proved to be a promising design strategy for facilitating the formation of optimal film morphology, and further improving the photovoltaic performance of organic solar cells (OSCs). Herein, two polymer donors named 2FP-1EH-1Si and 2FP-2Si with symmetrical and asymmetrical siloxane-terminated alkyl side chain substitution were designed and synthesized. The results demonstrate that compared with the alkyl side chain substituted polymer 2FP-2EH, the introduction of siloxane-terminated alkyl side chain not only regulates the miscibility between the polymer donor and small molecular acceptor (SMA), but also affects the spacing between the donor (D) and the acceptor (A) molecules. As a result, the asymmetrical and symmetrical siloxane-terminated alkyl side chain substituted polymer 2FP-1EH-1Si and 2FP-2Si exhibit lower surface energy, stronger self-aggregation ability and higher hole mobility. More importantly, the OSCs based on 2FP-1EH-1Si:IT-4F and 2FP-2Si:IT-4F exhibited gradually decreased energy loss, which is suppressed by controlling the D-A spacing, along with the increased open-circuit voltage (VOC) from 0.77 V to 0.80 V and then to 0.86 V. This work further reveals the regulation mechanism of siloxane-terminated alkyl chain on the photovoltaic performance of active layer materials for efficient OSCs with enhanced stability.

Will self-gifting of streamers hurt unions? Analyzing the union’s compensation mechanism for a live streaming supply chain

As an emerging online media for entertainment and social contact, live streaming already has a considerable market after its boom in recent years. On a live streaming platform, as content providers and the agents of providers, streamers and unions are the two most important roles on the supply side. Once streamers join a union, they will be paid according to the union’s compensation mechanism instead of directly paid by the platform.In practice, the union’s compensation mechanism usually contains a basic requirement for streamers’ proceeds, which may induce a specific self-gifting behavior among streamers — when a streamer’s proceeds have not met the requirement, the streamer may donate to himself/herself to increase his/her income. An interesting question is how should the union respond to such speculation, stand by or prohibit it?This paper considers a Stackelberg game between a union and a mass of streamers. The union utilizes a typical compensation mechanism with a basic proceeds requirement, and streamers are heterogeneous in their abilities. Using a backward induction approach, we derive the streamers’ optimal decisions for a given compensation mechanism and then numerically optimize the union’s compensation parameters.Our analysis reveals that when the union’s compensation parameters meet certain conditions, some streamers will donate to themselves, and more low-ability streamers will join the union. We also interestingly find that self-gifting behavior never hurts the union under its optimal compensation mechanism. The union can avoid the self-gifting behavior of streamers or even make this behavior beneficial to itself by properly setting the parameters of the compensation mechanism in different cases.

Analisis Rantai Pasok Buah Pepaya di Pulau Ambon

This study aimed to analyze the mechanism and efficiency of the papaya supply chain in Ambon Island. The analytical method uses qualitative and quantitative analysis. The qualitative analysis describes the mechanism of the papaya supply chain flow, while the quantitative analysis analyzes marketing margins, farmer's share, and marketing efficiency. Based on the results of the analysis, there are 2 supply chain channels for the papaya wulung supply chain in Saniani Maju, the first channel (Producers → Collectors in the mardika market → Consumers), the second channel (Producers → Rujak natsepa traders → Consumers). Papaya bangkok at Gerbang Mas has 1 channel (Farmers → Fris fresh market → Consumers). Analysis of efficiency and farmer share shows that all marketing channels are efficient because they meet the criteria, namely the calculation results of farmer's share ≥ 40% and marketing efficiency value < 50%.

Manajemen Rantai Pasok Agroindustri Pala di Desa Morella Kecematan Leihitu Kabupaten Maluku Tengah

This study aims to analyze the mechanism of supply chain flow, the value of supply chain performance, and supply chain efficiency in the Morella nutmeg juice MSME group. This research was conducted for 1 month in the nutmeg agro-industry in Morella Village, Leihitu District, Central Maluku Regency. The research method used was purposive sampling to determine the sample based on the characteristics or mechanism characteristics of the nutmeg juice supply chain. This study was analyzed using a descriptive method to describe the mechanism of the nutmeg juice agro-industry supply chain. The results showed that supply chain members of the Nutmeg Juice MSME Group consisted of suppliers, manufacturers, distributors, and consumers. There are two types of supply chain models for the Pala Morella Juice MSME group. The first is between manufacturers and distributors who work together to market nutmeg juice products to consumers. The second supply chain flow is the relationship between manufacturers, which is direct to the consumer, meaning that consumers come directly to the product production site and buy products directly from the company. Information flow occurs in two directions, for financial flows running from consumers-distributors-manufacturing-suppliers. Product flow starts from manufacturer-distributor-consumer. The flow of raw materials occurs only in one direction, namely from the nutmeg farmers in Morella Village.

Development and characterization of crosslinked k-carrageenan/sericin blend with covalent agents or thermal crosslink for indomethacin extended release

Modified release of multiparticulate pharmaceutical forms is a key therapeutic strategy to reduce side effects and toxicity caused by high and repeated doses of immediate-release oral drugs. This research focused on the encapsulation of indomethacin (IND) in the crosslinked k-Car/Ser polymeric matrix by covalent and thermal methods to evaluate drug delivery modulation and properties of the crosslinked blend. Therefore, the entrapment efficiency (EE %), drug loading (DL %) and physicochemical properties of the particles were investigated. The particles presented a spherical shape and a rough surface with a mean diameter of 1.38–2.15 mm (CCA) and 1.56–1.86 mm (thermal crosslink). FTIR investigation indicated the presence of IDM in the particles and X-ray pattern showed the maintenance of crystallinity of IDM. The in vitro release in acidic medium (pH 1.2) and phosphate buffer saline solution (pH 6.8) was 1.23–6.81 % and 81–100 %, respectively. Considering the results, the formulations remained stable after 6 months. The Weibull equation was adequately fitted for all formulations and a diffusion mechanism, swelling and relaxation of chain were observed. IDM-loaded k-carrageenan/sericin/CMC increases cell viability (> 75 % for neutral red and > 81 % for MTT). Finally, all formulations present gastro-resistance, pH response and altered release and have the potential to be used as drug delivery careers.

Photoinduced Minisci Reaction with Diazines: An Approach Toward Original Fused Heterocycles.

Herein, we developed a photoinduced Minisci reaction on a large panel of diazines with good to excellent yields (28 examples, 44% to 89%). The reaction using 4CzIPN (1 mol%) as photoinitiator was carried out under white LED irradiation and required a slight excess of the acid reagent (1.2 equiv.). Cyclization reactions were then developed to access original N-heterocycles building blocks for drug discovery programs. An extension of the reaction to continuous flow was also reported. Finally, the mechanism of the transformation was studied suggesting a plausible radical chain mechanism.