Structural Aspects Research Articles

Current Status, Development, And Application of Optimization Methods for Analog Circuits

The optimization of analog circuits has always relied on the experience and intuition of engineers to find suitable parameters to meet the requirements of the circuit, which is time-consuming and costly. This paper outlines and analyzes the optimization methods for analog circuits in recent years, and draws some summaries that can be used as references for subsequent optimization circuits. The optimization of analog circuits is mainly divided into the optimization of the performance of the hardware in the circuit and the optimization of the circuit structure. Hardware optimization, this paper mainly focuses on the optimization of diodes, transistors, field effect tubes and operational amplifiers, the four main hardware optimizations, from the material, structure, production process and other aspects of the analysis. For the optimization of circuit structure, this paper mainly analyzes from the aspects of algorithms, mathematical models, and the use of integrated methods. The significance of these optimization methods and the outstanding advantages and main application directions of different methods are further explained. The search for optimization methods can reduce the high time cost of analog circuit optimization that is purely dependent on experience and intuition, and is significant in increasing efficiency.

Spatiotemporal Distributions of the Thunderstorm and Lightning Structures over the Qinghai–Tibet Plateau

Utilizing data from the Tropical Rainfall Measuring Mission (TRMM) satellite’s precipitation radar (PR) and lightning imaging sensor (LIS), this study explores the spatiotemporal distributions of thunderstorm and lightning structures over the Qinghai–Tibet Plateau (QTP), an aspect that has not been explored previously. The structural aspects are crucial when considering the impact of thunderstorm and lightning activity in the atmospheric processes. Thunderstorms over the QTP show clear spatial variations in both vertical height and horizontal extension. In the southern region, the average heights of 20 dBZ and 30 dBZ echo tops typically exceed 11.2 and 9.3 km, respectively. Meanwhile, in the eastern part, the average coverage areas for reflectivity greater than 20 dBZ and 30 dBZ consistently surpass 1000 and 180 km2, respectively. The spatial distribution of thunderstorm vertical development height relative to the surface aligns more closely with the horizontal extension, indicating stronger convection in the eastern QTP. The thunderstorm flash rate shows an eastward and northward prevalence, while the thunderstorm flash density peaks in the western and northeastern QTP, with a minimum in the southeast. Furthermore, in the eastern QTP, lightning duration, spatial expansion, and radiance are more pronounced, with the average values typically exceeding 0.22 s, 14.5 km, and 0.50 J m−2 sr−1 μm−1, respectively. Monthly variations reveal heightened values during the summer season for thunderstorm vertical extension, areas with reflectivity greater than 30 dBZ, and lightning frequency. Diurnal variations highlight an afternoon increase in thunderstorm vertical and horizontal extension, lightning frequency, duration, and spatial scale. From a statistical perspective, under weak convective conditions, lightning length exhibits a positive correlation with thunderstorm convection intensity, contrasting with the opposite relationship suggested by previous studies. This article further analyzes and discusses the correlations between various thunderstorm and lightning structural parameters, enhancing our understanding of the distinctive features of thunderstorm and lightning activities in the QTP.

Taking Music Seriously: on the Dynamics of 'Mathemusical' Research with a Focus on Hexachordal Theorems

After presenting the general framework of `mathemusical' dynamics, we focus on one music-theoretical problem concerning a special case of homometry theory applied to music composition, namely Milton Babbitt's hexachordal theorem. We briefly discuss some historical aspects of homometric structures and their ramifications in crystallography, spectral analysis and music composition via the construction of rhythmic canons tiling the integer line. We then present the probabilistic generalization of Babbitt's result we recently introduced in a paper entitled ''New hexachordal theorems in metric spaces with probability measure'' and illustrate the new approach with original constructions and examples.

Unveiling the Dual-Enhancing Mechanisms of Kinetically Controlled Silver Nanoparticles on Piezoelectric PVDF Nanofibers for Optimized SERS Performance.

Noble metal nanoparticle (NMP)-based composite substrates have garnered significant attention as a highly promising technique for surface-enhanced Raman scattering (SERS) in diverse scientific disciplines because their remarkable ability to amplify and functionalize Raman signals has positioned them as valuable tools for molecular detection. However, optimizing the size and distribution of NMPs has not received sufficient emphasis because of challenges associated with the precise control of deposition and the modulation of reducing rates during growth. In this research, we achieved the optimized size and spatial patterns of AgNWs on electrospun poly(vinylidene fluoride) (PVDF) nanofibers by utilizing a polydopamine (PDA) layer as a mild and controllable reduction mediator, by which the size and density of the AgNWs could be relatively precisely manipulated, achieving a dense distribution of effective "hot spots". On the other hand, harnessing the inherent piezoelectric properties of the electrospun PVDF nanofibers further boosted the LSPR effect during the SERS test, forming a flexible dual-enhancing composite SERS substrate with excellent sensitivity. In addition to addressing structural aspects, exploiting synergistic systems capable of transferring external energy or forces to enhance the SERS performances presents a compelling avenue to broaden the practical applications of SERS. The dual-enhanced substrate achieved an exceptional enhancement factor (EF) of 1.05 × 108 and a low detection limit (LOD) of 10-10 M during the SERS test. This study focuses on integrating NMPs with electrospun piezoelectric polymer nanofibers to develop a dual-enhancing SERS substrate with excellent sensitivity and practicality. The findings provide valuable insights into controllably depositing NMPs on electrospun polymer fibers and hold significant implications for the development of highly sensitive and practical SERS substrates across various applications.

P134 Characterization for the similarity assessment between proposed biosimilar SB17 and ustekinumab reference product using state-of-the-art analytical method

Abstract Background SB17 is being developed as a proposed biosimilar to ustekinumab reference product (RP), a human monoclonal antibody (IgG1 kappa immunoglobulin) that binds to the common p40 subunit of cytokines interleukin (IL)-23 and IL-12. Binding to this subunit prevents interaction with their receptor, resulting in modulation the immune system responses which play a key role in the inflammatory disease. The objective of this study was to demonstrate structural, physicochemical, and biological similarity between ustekinumab RP and SB17 using various state-of-the-art analytical methods. Methods Comprehensive analytical characterization was conducted with side-by-side comparison of SB17 with the EU and US ustekinumab RP using various analytical methods. Comparisons included purity, product-related impurity, charge heterogeneity, primary structure, post-translational modification, higher order structure, quantity, Fab-related biological activities (potency and binding activity), and Fc-related biological activities. Results Based on the analytical similarity assessment, the structural, physicochemical, and biological characterization results demonstrated that SB17 is highly similar to the EU and US ustekinumab RP. In the structural aspects, it was confirmed that there is no clinically meaningful difference between post-translational modification profiles and higher order structures of SB17 compared to the ustekinumab RP. Product-related impurities in the form of aggregates were also confirmed to be similar. SB17 has a lower of acidic and basic peaks compared with ustekinumab RP, due to the difference in producing cell line. Ustekinumab RP is expressed in an Sp2/0 cell line, whereas SB17 is expressed in CHO cell line. However, the difference between SB17 and ustekinumab RP in the charge variants is not considered clinically meaningful since equivalent biological activity was observed. In case of mechanism of action (MoA)-related biological activities, SB17 is highly similar to the EU and US ustekinumab RP with respect to overall critical and non-critical quality attributes analyzed. Moreover, similarity or lack of activity in Fc-related biological activities was also confirmed. Based on these results, SB17 is expected to have highly similar safety and efficacy as compared to ustekinumab RP. Conclusion In summary, the overall analytical characterization and similarity assessment results show that SB17 is highly similar to the EU and US ustekinumab RP in terms of structural, physicochemical, biophysical, biological attributes.

The Semiotics of the Title in the Diwan (Qadas Jasad) By the writer: Mona Bint Mohammed

The title is considered an essential element of literary text; it is the first threshold through which the reader enters the text. The title has evolved in literary text to become an independent science itself, and the first way to decipher the text and interpret it. It is considered a sign among the semiotic signs that appear at the beginning of the text, indicating its content as a whole. It is like a key that refers to the world of the text and becomes a reference for it. Given the importance of the title in literary texts, my study is dedicated to discussing the semiotics of the title in the collection "Qadas Jasad" by the writer (Mona Bint Mohammed), in an attempt to answer the following questions: - What is the semiotics of the title? To what extent does the semiotic approach apply to the collection "Qadas Jasad"? - What is the referential significance of the semiotics of the title in the collection? - Has the semiotic approach achieved different literary critical results? Research Objectives: My research study aims to achieve a set of objectives, the most important of which are: - Clarifying the nature of semiotics and the principles of modern semiotic methodology. - Presenting the most important contemporary semiotic trends and their characteristics. - Conducting a semiotic study of the title in the collection of poems "Qadas Jasad" and explaining the important dimensions included in the titles of the collection. - Explaining the semantic structure of the title by presenting the structural and semantic aspects of the title and revealing the relationship between the titles of the poems and their contents. Research Literature: The idea of the project came to support the connection between literature and society, as specialized studies in Najrani literature are very few, including: - The poetry movement in Najran during the Jahiliyyah and the early Islamic period, by Faiza Raddad Al-Otaibi, published by Najran Literary Club in 1430 AH (published master's thesis). - Games for boys in ancient Arabic poetry and their connection to games in the Najran region in modern times, Dr. Essam Mohammed Qubaisi, Dr. Zuhair bin Hassan Al-Amri, Journal of the Faculty of Dar Al-Uloom at Al-Fayoum University, 2014. - Folk proverbs in the Najran region: An objective study, Dr. Zuhair bin Hassan Al-Amri, Journal of the Faculty of Dar Al-Uloom at Cairo University, 2016. - Yazid bin Abdul Madaan Al-Najrani: His political role and literary heritage between two eras, Dr. Awad bin Abdullah bin Nahi, Dr. Essam Mohammed Qubaisi, Journal of Bisha University for Humanities, 2022. Methodology of Research: In my research, I have adopted the semiotic approach; because the title is a semiotic sign that needs to be explored in terms of its dimensions and meanings; through: deconstruction, interpretation, and analysis. Therefore, I have relied on both: the analytical method in analyzing the structural and semantic composition of the title, and the inductive method in extracting the relationship between the content of the poem and the title. Research Plan: I have divided my study into: - The first topic: The nature of semiotic methodology, its direction, and its origin. - The first subtopic: Definition of semiotic methodology in language and terminology. - The second subtopic: Semiotic directions. - The third subtopic: The emergence of semiotics in contemporary critical studies. - The second topic: The title and its functions. - The first subtopic: Definition of "title" in language and terminology. - The second subtopic: The importance, types, and functions of the title. - The third topic: The semiotics of the title in the Diwan (Qadas Jasad). - The first subtopic: The structural organization of the title in the Diwan (Qadas Jasad). - The second subtopic: The semantic structure of the title in the Diwan (Qadas Jasad). - Then the conclusion, which includes the most important results. Then the books and references. - The first topic: The nature of semiotic methodology, direction, and origin.

International migration and the NGOs working in the field of migration in Turkey

AbstractThis study aims to analyse the activities and discourses of the non‐governmental organizations (NGOs) working in the field of migration in Turkey. The research explores how the NGOs frame the issue of migration differently and how they define and comprehend migration, migrants, and refugees. The article discusses whether the NGOs view refugees as subjects needing help, support, and protection or as actors who have rights and must be empowered and argues that there is tension between the two approaches. These points are discussed through a field study, conducted in 2020 (between February and April), comprising in‐depth interviews with representatives of 13 NGOs working in the field of migration. The study points to structural, historical, and conjectural causes and aspects of the weakness of rights‐based attitudes and activities among the NGOs working in the field of migration in Turkey. The article finds out that the actions of the NGOs working in the field of migration are concentrated on the basic needs of refugees, and structural limitations, such as political pressure, political polarization, and capacity problems, push the NGOs to evaluate the issue of migration within relatively narrow frames. The article also stresses the importance of an enabling political and legal environment and a coherent and structured communication strategy to promote a rights‐based migration agenda.

Effect of high concentration of ZnO on the structural and optical properties of silicate glass system

An investigation was conducted to explore the optimum composition to fabricate a zinc silicate glass substrate for optoelectronic device applications. The composition was determined based on the empirical formula (ZnO)x-(SiO2)1-x, where x = 0.40, 0.50, 0.60 and 0.70 wt%, which was prepared by the conventional melt quenching technique. The focus is on characterizing the physical and structural aspects as well as the optical properties of the glass substrate. The physical properties of zinc silicate samples were assessed using the densitometer and their physical appearance. In addition, the materials' amorphous and glassy characteristics were verified using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques. Finally, ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence spectrometer were used to study the optical properties of samples. The density of the samples was observed to increase from 2805 to 3878 kg/m3 as the percentage of ZnO in the glass composition increased. X-ray diffraction analysis indicated the absence of sharp peaks in the samples containing up to 0.60 wt% of ZnO, suggesting the presence of an amorphous phase. Furthermore, the results of this study indicate that ZnO-SiO2 glass substrate samples favor direct forbidden transitions, with an increase in ZnO leading to higher absorption and consequently a lower band gap. The photoluminescence spectrum showed blue light emissions at 422 nm, associating with the variation of band gaps in the ZnO phase. Overall, from the interesting results achieved, this zinc silicate-based composite material at 0.60 wt% ZnO can be a potent candidate in optoelectronic applications, among other concentrations used in this study.

NOVEL SUSU DAN TELUR KARYA MIEKO KAWAKAMI TERJEMAHAN ASRI PRATIWI WULANDARI: KAJIAN FEMINISME RADIKAL

The topic of feminism in Japan is something that society has not yet fully accepted. This is the reason why researchers chose the novel Susu and Eggs to be used as the object of study. The discrimination that occurs against female characters in the novel leads to extreme actions and thoughts regarding women's freedom regarding their rights. Therefore, the novel Susu and Eggs is studied using radical feminism theory. The aim of this research is to describe the structural analysis and aspects of radical feminism in the object of study. Data discovery was carried out using the library study method, namely reading the novel in its entirety. The description of the data is carried out through qualitative descriptive methods. The research results show that there is a relationship between the title, theme and characterization in the novel. The title relates to the major theme which is supported by the minor theme. The theme is depicted through events that support the characters' characters. On the other hand, the aspects of radical feminism found are divided into five parts, namely: (1) women and their bodies which are related to Midoriko and Natsuko. Midoriko as a teenager who hates the nature of women, then Natsuko as a single woman who cannot find pleasure in sex, but wants to have children through a sperm donor; (2) the inequality of roles in the household which is depicted through the character Yusa Rika who hates her ex-husband; (3) women's beauty standards which include women's body shape and nipple color; (4) stereotypes about women's bodies that discuss women's instincts to get pregnant and societal stigma that prioritizes the penis over the vagina; (5) and sexual violence which includes the act of rape against the character Zen Yuriko.

Structural aspects of dehydration of NaBiO3-based compounds probed by XRD and NMR

The phase transformation in a mixture of hydrated NaBiO3 · nH2O and dehydrated NaBiO3 phase is studied during heating. The results indicate that generally the transformation occurs in two stages. At the first stage the hydrated NaBiO3 · nH2O phase converts to an anhydrous defective intermediate phase with the ilmenite-type structure similar to the initial dehydrated NaBiO3, but with increased lattice parameter c. According to nuclear magnetic resonance (NMR) the intermediate phase is associated with additional inequivalent Na. In terms of the Na–O interatomic distances the intermediate phase is closer to the hydrated phase, but in terms of the symmetry of Na coordination polyhedron it is already closer to the dehydrated one. The Na of the intermediate phase still remains in the sample after the complete dehydration and at the second stage there is a gradual recrystallization of the intermediate phase towards the initial NaBiO3 phase.

The Trimeric Autotransporter Adhesin EmaA and Infective Endocarditis.

Infective endocarditis (IE), a disease of the endocardial surface of the heart, is usually of bacterial origin and disproportionally affects individuals with underlying structural heart disease. Although IE is typically associated with Gram-positive bacteria, a minority of cases are caused by a group of Gram-negative species referred to as the HACEK group. These species, classically associated with the oral cavity, consist of bacteria from the genera Haemophilus (excluding Haemophilus influenzae), Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. Aggregatibacter actinomycetemcomitans, a bacterium of the Pasteurellaceae family, is classically associated with Aggressive Periodontitis and is also concomitant with the chronic form of the disease. Bacterial colonization of the oral cavity serves as a reservoir for infection at distal body sites via hematological spreading. A. actinomycetemcomitans adheres to and causes disease at multiple physiologic niches using a diverse array of bacterial cell surface structures, which include both fimbrial and nonfimbrial adhesins. The nonfimbrial adhesin EmaA (extracellular matrix binding protein adhesin A), which displays sequence heterogeneity dependent on the serotype of the bacterium, has been identified as a virulence determinant in the initiation of IE. In this chapter, we will discuss the known biochemical, molecular, and structural aspects of this protein, including its interactions with extracellular matrix components and how this multifunctional adhesin may contribute to the pathogenicity of A. actinomycetemcomitans.

Fast-charging graphite anode for lithium-ion batteries: Fundamentals, strategies, and outlooks

The basic requirements for lithium-ion batteries in the field of electric vehicles are fast charging and high energy density. This will enhance the competitiveness of electric vehicles in the market while reducing greenhouse gas emissions and effectively preventing environmental pollution. However, the current lithium-ion batteries using graphite anodes cannot achieve the goal of fast charging without compromising electrochemical performance and safety issue. This article analyzes the mechanism of graphite materials for fast-charging lithium-ion batteries from the aspects of battery structure, charge transfer, and mass transport, aiming to fundamentally understand the failure mechanisms of batteries during fast charging. In addition, we review and discuss recent advances in strategies for optimizing fast-charging performance and summarize current improvement methods in graphite electrodes, electrolytes, battery structures, and charging algorithms. Moreover, the challenges and promising concepts for developing future fast-charging graphite anode are emphasized. This review is of great significance for better designing and optimizing graphite materials for high-safety and fast-charging lithium-ion batteries.

High‐performance diffusion model for inverse design of high Tc superconductors with effective doping and accurate stoichiometry

AbstractThe pursuit of designing superconductors with high Tc has been a long‐standing endeavor. However, the widespread incorporation of doping in high Tc superconductors significantly impacts electronic structure, intricately influencing Tc. The complex interplay between the structural composition and material performance presents a formidable challenge in superconductor design. Based on a novel generative model, diffusion model, and doping adaptive representation: three‐channel matrix, we have designed a high Tc superconductors inverse design model called Supercon‐Diffusion. It has achieved remarkable success in accurately generating chemical formulas for doped high Tc superconductors. Supercon‐Diffusion is capable of generating superconductors that exhibit high Tc and excels at identifying the optimal doping ratios that yield the peak Tc. The doping effectiveness (55%) and electrical neutrality (55%) of the generated doped superconductors exceed those of traditional GAN models by more than tenfold. Density of state calculations on the structures further confirm the validity of the generated superconductors. Additionally, we have proposed 200 potential high Tc superconductors that have not been documented yet. This groundbreaking contribution effectively reduces the search space for high Tc superconductors. Moreover, it successfully establishes a bridge between the interrelated aspects of composition, structure, and property in superconductors, providing a novel solution for designing other doped materials.image

Exploring the DNA2-PNA heterotriplex formation in targeting the Bcl-2 gene promoter: A structural insight by physico-chemical and microsecond-scale MD investigation

Peptide Nucleic Acids (PNAs) represent a promising tool for gene modulation in anticancer treatment. The uncharged peptidyl backbone and the resistance to chemical and enzymatic degradation make PNAs highly advantageous to form stable hybrid complexes with complementary DNA and RNA strands, providing higher stability than the corresponding natural analogues. Our and other groups’ research has successfully shown that tailored PNA sequences can effectively downregulate the expression of human oncogenes using antigene, antisense, or anti-miRNA approaches. Specifically, we identified a seven bases-long PNA sequence, complementary to the longer loop of the main G-quadruplex structure formed by the bcl2midG4 promoter sequence, capable of downregulating the expression of the antiapoptotic Bcl-2 protein and enhancing the anticancer activity of an oncolytic adenovirus. Here, we extended the length of the PNA probe with the aim of including the double-stranded Bcl-2 promoter among the targets of the PNA probe. Our investigation primarily focused on the structural aspects of the resulting DNA2-PNA heterotriplex that were determined by employing conventional and accelerated microsecond-scale molecular dynamics simulations and chemical-physical analysis. Additionally, we conducted preliminary biological experiments using cytotoxicity assays on human A549 and MDA-MB-436 adenocarcinoma cell lines, employing the oncolytic adenovirus delivery strategy.

The Impact of Large-Scale Water Diversion Projects on the Water Supply Network: A Case Study in Southwest China

The uneven spatial and temporal distribution of water resources has consistently been one of the most significant limiting factors for social development in many regions. Furthermore, with the intensification of climate change, this inequality is progressively widening, posing a critical challenge to the sustainable development of human societies. The construction of large-scale water projects has become one of the crucial means to address the contradictions between water supply and demand. Thus, evaluating the functional aspects of water source network structures and systematically planning the layout of engineering measures in a scientifically reasonable manner are pressing issues that require urgent attention in current research efforts. Addressing this, our study takes the Erhai Lake basin and the surrounding areas in southwest China as the study area and combines landscape ecology and network analysis theory methods to propose a water supply network analysis method that takes into account both structure and node characteristics. Based on this methodology, we analyze the connectivity characteristics of water supply networks in the Erhai region under current (2020) and future (2035) planning scenarios. The results show that there were 215 nodes and 216 links in the water supply network of the Erhai Lake basin in 2020; with the implementation of a series of water conservancy projects, the planned 2035 water supply network will increase by 122 nodes and 163 links, and the connectivity of the regional water network will be significantly improved. Also, we identify some key nodes in the network, and the results show that the water supply network in 2035 will have obvious decentralization characteristics compared with that in 2020. And, based on the network degradation analysis, we find that with the implementation of engineering measures, the resilience of the water supply network will be significantly strengthened by 2035, with stronger risk tolerance. This study extends the quantitative representation of water source network characteristics, which can provide a useful reference for water network structure planning and optimization.

The Assessment of Industrial Agglomeration in China Based on NPP-VIIRS Nighttime Light Imagery and POI Data

Industrial agglomeration, as a typical aspect of industrial structures, significantly influences policy development, economic growth, and regional employment. Due to the collection limitations of gross domestic product (GDP) data, the traditional assessment of industrial agglomeration usually focused on a specific field or region. To better measure industrial agglomeration, we need a new proxy to estimate GDP data for different industries. Currently, nighttime light (NTL) remote sensing data are widely used to estimate GDP at diverse scales. However, since the light intensity from each industry is mixed, NTL data are being adopted less to estimate different industries’ GDP. To address this, we selected an optimized model from the Gaussian process regression model and random forest model to combine Suomi National Polar-Orbiting Partnership—Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) NTL data and points-of-interest (POI) data, and successfully estimated the GDP of eight major industries in China for 2018 with an accuracy (R2) higher than 0.80. By employing the location quotient to measure industrial agglomeration, we found that a dominated industry had an obvious spatial heterogeneity. The central and eastern regions showed a developmental focus on industry and retail as local strengths. Conversely, many western cities emphasized construction and transportation. First-tier cities prioritized high-value industries like finance and estate, while cities rich in tourism resources aimed to enhance their lodging and catering industries. Generally, our proposed method can effectively measure the detailed industry agglomeration and can enhance future urban economic planning.

Overview of Protocols and Standards for Wireless Sensor Networks in Critical Infrastructures

This paper highlights the crucial role of wireless sensor networks (WSNs) in the surveillance and administration of critical infrastructures (CIs), contributing to their reliability, security, and operational efficiency. It starts by detailing the international significance and structural aspects of these infrastructures, mentions the market tension in recent years in the gradual development of wireless networks for industrial applications, and proceeds to categorize WSNs and examine the protocols and standards of WSNs in demanding environments like critical infrastructures, drawing on the recent literature. This review concentrates on the protocols and standards utilized in WSNs for critical infrastructures, and it concludes by identifying a notable gap in the literature concerning quality standards for equipment used in such infrastructures.

Stabilization of NH- Group Adjacent to Naked Silicon(II) Atom in Base Stabilized Aminosilylenes.

Aminosilylene, comprising reactive NH- and Si(II) sites next to each other, is an intriguing class of compounds due to its ability to show diverse reactivity. However, stabilizing the reactive NH- group next to the free Si(II) atom is challenging and has not yet been achieved. Herein, we report the first examples of base stabilized free aminosilylenes Ar*NHSi(PhC(Nt Bu)2 ) (1 a) and Mes*NHSi(PhC(Nt Bu)2 ) (1 b) (Ar*=2,6-dibenzhydryl-4-methylphenyl and Mes*=2,4,6-tri-tert-butylphenyl), tolerating a NH- group next to the naked Si(II) atom. Remarkably, 1 a and 1 b exhibited interesting differences in their reactivity upon heating. With 1 a, an intramolecular C(sp3 )-H activation of one of the benzhydryl methine hydrogen atoms to the Si(II) atom produced the five-membered cyclic silazane 2. However, with 1 b, a rare 1,2-hydrogen shift to the Si(II) atom afforded a silanimine 3, with a hydride ligand attached to an unsaturated silicon atom. Further, the coordination capabilities of 1 a were also tested with Ru(II) and Fe(0) precursors. Treatments of 1 a with [Ru(η6 -p-cymene)Cl2 ]2 led to the isolation of a η6 -arene tethered complex [RuCl2 {Ar*NHSi(PhC(t BuN)2 )-κ1 -Si-η6 -arene}] (4), whereas with the Fe(CO)5 precursor a Fe(0) complex [Fe(CO)4 {Ar*NHSi(PhC(t BuN)2 )-κ1 -Si}] (5) was obtained. Density functional theory (DFT) calculations were conducted to shed light on the structural, bonding, and energetic aspects in 1-5.

Stabilization of NH− Group Adjacent to Naked Silicon(II) Atom in Base Stabilized Aminosilylenes

AbstractAminosilylene, comprising reactive NH− and Si(II) sites next to each other, is an intriguing class of compounds due to its ability to show diverse reactivity. However, stabilizing the reactive NH− group next to the free Si(II) atom is challenging and has not yet been achieved. Herein, we report the first examples of base stabilized free aminosilylenes Ar*NHSi(PhC(NtBu)2) (1 a) and Mes*NHSi(PhC(NtBu)2) (1 b) (Ar*=2,6‐dibenzhydryl‐4‐methylphenyl and Mes*=2,4,6‐tri‐tert‐butylphenyl), tolerating a NH− group next to the naked Si(II) atom. Remarkably, 1 a and 1 b exhibited interesting differences in their reactivity upon heating. With 1 a, an intramolecular C(sp3)−H activation of one of the benzhydryl methine hydrogen atoms to the Si(II) atom produced the five‐membered cyclic silazane 2. However, with 1 b, a rare 1,2‐hydrogen shift to the Si(II) atom afforded a silanimine 3, with a hydride ligand attached to an unsaturated silicon atom. Further, the coordination capabilities of 1 a were also tested with Ru(II) and Fe(0) precursors. Treatments of 1 a with [Ru(η6‐p‐cymene)Cl2]2 led to the isolation of a η6‐arene tethered complex [RuCl2{Ar*NHSi(PhC(tBuN)2)‐κ1‐Si‐η6‐arene}] (4), whereas with the Fe(CO)5 precursor a Fe(0) complex [Fe(CO)4{Ar*NHSi(PhC(tBuN)2)‐κ1‐Si}] (5) was obtained. Density functional theory (DFT) calculations were conducted to shed light on the structural, bonding, and energetic aspects in 1–5.

Structural and Evolutionary Aspects of Plant Endocytosis.

Endocytosis is an essential eukaryotic process that maintains the homeostasis of the plasma membrane proteome by vesicle-mediated internalization. Its predominant mode of operation utilizes the polymerization of the scaffold protein clathrin forming a coat around the vesicle; therefore, it is termed clathrin-mediated endocytosis (CME). Throughout evolution, the machinery that mediates CME is marked by losses, multiplications, and innovations. CME employs a limited number of conserved structural domains and folds, whose assembly and connections are species dependent. In plants, many of the domains are grouped into an ancient multimeric complex, the TPLATE complex, which occupies a central position as an interaction hub for the endocytic machinery. In this review, we provide an overview of the current knowledge regarding the structural aspects of plant CME, and we draw comparisons to other model systems. To do so, we have taken advantage of recent developments with respect to artificial intelligence-based protein structure prediction.