Domain Structure Research Articles

Design of a Wearable Exoskeleton Piano Practice Aid Based on Multi-Domain Mapping and Top-Down Process Model.

This study designs and develops a wearable exoskeleton piano assistance system for individuals recovering from neurological injuries, aiming to help users regain the ability to perform complex tasks such as playing the piano. While soft robotic exoskeletons have proven effective in rehabilitation therapy and daily activity assistance, challenges remain in performing highly dexterous tasks due to structural complexity and insufficient motion accuracy. To address these issues, we developed a modular division method based on multi-domain mapping and a top-down process model. This method integrates the functional domain, structural domain, and user needs domain, and explores the principles and methods for creating functional construction modules, overcoming the limitations of traditional top-down approaches in design flexibility. By closely combining layout constraints with the design model, this method significantly improves the accuracy and efficiency of module configuration, offering a new path for the development of piano practice assistance devices. The results demonstrate that this device innovatively combines piano practice with rehabilitation training and through the introduction of ontological modeling methods, resolves the challenges of multidimensional needs mapping. Based on five user requirements (P), we calculated the corresponding demand weight (K), making the design more aligned with user needs. The device excels in enhancing motion accuracy, interactivity, and comfort, filling the gap in traditional piano assistance devices in terms of multi-functionality and high adaptability, and offering new ideas for the design and promotion of intelligent assistive devices. Simulation analysis, combined with the motion trajectory of the finger's proximal joint, calculates that 60° is the maximum bending angle for the aforementioned joint. Physical validation confirms the device's superior performance in terms of reliability and high-precision motion reproduction, meeting the requirements for piano-assisted training. Through multi-domain mapping, the top-down process model, and modular design, this research effectively breaks through the design flexibility and functional adaptability bottleneck of traditional piano assistance devices while integrating neurological rehabilitation with music education, opening up a new application path for intelligent assistive devices in the fields of rehabilitation medicine and arts education, and providing a solution for cross-disciplinary technology fusion and innovative development.

Amino acid substitution patterns in the <i>E6</i> and <i>E7</i> Proteins of HPV type 16: Phylogeography and Evolution

The E6 and E7 proteins of human papillomavirus (HPV) play a key role in the oncogenesis of papillomavirus infection. Data on the variability of these proteins are limited, and the factors affecting their variability are poorly understood. We analyzed the variability of the currently known sequences of HPV type 16 (HPV16) E6 and E7 proteins, taking into account their geographic origin and year of sample collection, as well as the direction of their evolution in major geographic regions of the world. All sequences belonging to HPV16 genome fragments encoding E6 and E7 oncoproteins were downloaded from the NCBI GenBank database on October 6, 2022. Samples were filtered according to the following parameters: the sequence includes at least one of the two whole open reading frames, the collection date and the country of origin are known. A total of 3,651 full-genome nucleotide sequences encoding the E6 protein and 4,578 full-genome nucleotide sequences encoding the E7 protein were sampled. The nucleotide sequences obtained after sampling and alignment were converted to amino acid sequences and analyzed using MEGA11, R, RStudio, Jmodeltest 2.1.20, BEAST v1.10.4, Fastcov, and Biostrings software. The highest variability in E6 protein structure was recorded at positions 17, 21, 32, 85, and 90, while in E7, positions 28, 29, 51, and 77 were the most variable. The samples were divided geographically into 5 heterogeneous groups: African, European, American, Southwest and South Asia and Southeast Asia. Unique amino acid substitutions (AA-substitutions) in the E6/E7 proteins of HPV16, presumably characteristic of certain ethnic groups, were identified for a number of countries. They are mainly localized in sites of known B- and T-cell epitopes and relatively rarely in structural and functional domains. The revealed differences in AA-substitutions in different ethnic groups and their colocalization with clusters of B- and T-cell epitopes suggest their possible relationship with the geographical distribution of alleles and haplotypes of the major histocompatibility complex (HLA). This may lead to the recognition of a different set of B- and T-cell epitopes of the virus, resulting in regional differences in the direction of epitope drift. Phylogenetic analysis of the nucleotide sequences encoding the E6 protein of HPV16 revealed a common ancestor, confirmed regional clustering of the E6 protein gene sequences by the set of the most common AA-substitutions, and identified cases of reversion of individual AA-substitutions when the virus distribution region changed. For the E7 protein, a similar analysis was not possible due to high sequence homology. Covariance analysis of the pooled sample revealed that there was no relationship between amino acid residues in the E6 protein, in the E7 protein, and between E6 and E7. Data obtained are important for the development of therapeutic vaccines against HPV of high carcinogenic risk.

Impact of ion exchange on vibrational modes in Rb-doped KTiOPO4 : A Raman spectroscopy study on the interplay between ion exchange and polarization switching

Recently, ion exchange (IE) has been used to periodically modify the coercive field (Ec) of the crystal prior to periodic poling, to fabricate fine-pitch domain structures in Rb-doped KTiOPO4 (RKTP). Here, we use micro-Raman spectroscopy to understand the impact of IE on the vibrational modes related to the Rb/K lattice sites, TiO6 octahedra, and PO4 tetrahedra, which all form the basis of the RKTP crystal structure. We analyze the Raman spectra of three different RKTP samples: (1) a RKTP sample that shows a poled domain grating only, (2) a RKTP sample that has an Ec grating only, and (3) a RKTP sample that has both an Ec and a domain grating of the nominally same spacing. This allows us to determine the impact of IE on the vibrational modes of RKTP. We characterize the changes in the lower Raman peaks related to the alkali-metal ions, as well as observe lattice modifications induced by the incorporation of Rb+ that extend further into the crystal bulk than the expected IE depth. Moreover, the influence of IE on the domain walls is also manifested in their Raman peak shift. We discuss our results in terms of the deformation of the PO4 and TiO6 groups. Our results highlight the intricate impact of IE on the crystal structure and how it facilitates periodic poling, paving the way for further development of the Ec-engineering technique. Published by the American Physical Society 2024

Genotype and Haplotype Analysis With In Silico Prediction of TMPRSS2 Gene in Jordanian Population.

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a global health concern. The entry of the virus into host cells is facilitated by the transmembrane protease serine 2 (TMPRSS2) receptor, and genetic variations in the TMPRSS2 gene may influence disease susceptibility. However, there is a lack of knowledge regarding TMPRSS2 genetic variants and haplotypes in the Jordanian population. This study aimed to characterize the genotype and haplotype variations in the TMPRSS2 binding domain with SARS-CoV-2 among Jordanian volunteers. The binding domain of TMPRSS2 with SARS-CoV-2 (Exons 9 and 10) was amplified using polymerase chain reaction (PCR) for a random sample of 120 healthy unrelated Jordanian volunteers, followed by Sanger DNA sequencing for the PCR products. The effect of the novel genetic variants on the TMPRSS2 protein structure was predicted using in silico methods. The results showed significant (p<0.05, chi-square) allele frequencies for known TMPRSS2 variants, with c.888C>T being the most prevalent among Jordanian volunteers. Novel genetic variants, including c.869A>G and c.923T>A, were also identified, with the latter being the most common novel variant. Haplotype analysis showed that the most prevalent TMPRSS2 haplotype is c.911G/1051A/1052T/1010+45C/1011-38T/1011-52C/1011-54A. In silico programs predicted that TMPRSS2 c.923T>A and c.1052T>A variants affect transmembrane proteins and catalytic sites. This research provides information about the gene structure of the TMPRSS2 binding domain in Jordanians. Some of the identified variants, especially c.923T>A, may influence protein function, warranting further in vitro and in vivo investigations. In addition, further clinical research studies are needed to link the identified TMPRSS2 variants with COVID-19 susceptibility and severity among Jordanians.

N-terminus α-synuclein detection reveals new and more diverse aggregate morphologies in multiple system atrophy and Parkinson’s disease

BackgroundParkinson’s disease (PD) and multiple system atrophy (MSA) are classified as α-synucleinopathies and are primarily differentiated by their clinical phenotypes. Delineating these diseases based on their specific α-synuclein (α-Syn) proteoform pathologies is crucial for accurate antemortem biomarker diagnosis. Newly identified α-Syn pathologies in PD raise questions about whether MSA exhibits a similar diversity. This prompted the need for a comparative study focusing on α-Syn epitope-specific immunoreactivities in both diseases, which could clarify the extent of pathological overlap and diversity, and guide more accurate biomarker development.MethodsWe utilised a multiplex immunohistochemical approach to detect multiple structural domains of α-Syn proteoforms across multiple regions prone to pathological accumulation in MSA (n = 10) and PD (n = 10). Comparison of epitope-specific α-Syn proteoforms was performed in the MSA medulla, inferior olivary nucleus, substantia nigra, hippocampus, and cerebellum, and in the PD olfactory bulb, medulla, substantia nigra, hippocampus, and entorhinal cortex.ResultsN-terminus and C-terminus antibodies detected significantly more α-Syn pathology in MSA than antibodies for phosphorylated (pS129) α-Syn, which are classically used to detect α-Syn. Importantly, C-terminus immunolabelling is more pronounced in MSA compared to PD. Meanwhile, N-terminus immunolabelling consistently detected the highest percentage of α-Syn across pathologically burdened regions of both diseases, which could be of biological significance. As expected, oligodendroglial involvement distinguished MSA from PD, but in contrast to PD, no substantial astrocytic or microglial α-Syn accumulation in MSA occurred. These data confirm glial-specific changes between these diseases when immunolabelling the N-terminus epitope. In comparison, N-terminus neuronal α-Syn was present in PD and MSA, with most MSA neurons lacking pS129 α-Syn proteoforms. This explains why characterisation of neuronal MSA pathologies is lacking and challenges the reliance on pS129 antibodies for the accurate quantification of α-Syn pathological load across α-synucleinopathies.ConclusionsThese findings underscore the necessity of utilising a multiplex approach to detect α-Syn, most importantly including the N-terminus, to capture the entire spectrum of α-Syn proteoforms in α-synucleinopathies. The data provide novel insights toward the biological differentiation of these α-synucleinopathies and pave the way for more refined antemortem diagnostic methods to facilitate early identification and intervention of these neurodegenerative diseases.

Genome-Wide Identification and Expression Analysis of HSP70 Gene Family Under High-Temperature Stress in Lettuce (Lactuca sativa L.).

The heat shock protein 70 (HSP70) family plays an important role in the growth and development of lettuce and in the defense response to high-temperature stress; however, its bioinformatics analysis in lettuce has been extremely limited. Genome-wide bioinformatics analysis methods such as chromosome location, phylogenetic relationships, gene structure, collinearity analysis, and promoter analysis were performed in the LsHSP70 gene family, and the expression patterns in response to high-temperature stress were analyzed. The mechanism of LsHSP70-19 in heat resistance in lettuce was studied by virus-induced gene silencing (VIGS) and transient overexpression techniques. The results showed that a total of 37 LsHSP70 genes were identified by the Hidden Markov Model (HMM) and Protein Family Database (Pfam). These 37 LsHSP70 genes were classified into groups A, B, C, and D by phylogenetic relationships. They were mainly localized on seven chromosomes except for chromosome 3; gene structure analysis showed that LsHSP70 contained 1-9 exons, and the protein structure domains of genes in the same group were highly conserved. The covariance analysis showed that nine pairs of LsHSP70 genes existed between LsHSP70 members, and lettuce LsHSP70 and sunflower HaHSP70 had been more conserved in the evolutionary process. The promoter analysis showed that there were a large number of cis-acting elements related to phytohormones, growth, development, stress, and light response in LsHSP70. In addition, the results of the expression pattern analysis for all LsHSP70 genes under high-temperature stress showed that 28 out of 37 LsHSP70 genes were able to respond to heat stress, and only LsHSP70-8, LsHSP70-14, LsHSP70-19, LsHSP70-23, and LsHSP70-24 were able to respond rapidly to heat stress (2 h). The expression of LsHSP70-19 was higher at different periods under high-temperature stress; the overexpression of LsHSP70-19, the plant fresh weight, and the root weight were better than the control (CK); and the heat resistance was better. These results suggest that LsHSP70-19 may play an important role under high-temperature stress in lettuce.

Molecular dynamics investigation of heteroepitaxial growth of quaternary AlInGaN on wurtzite-GaN surface along [0001] direction

We conducted molecular dynamics simulations of heteroepitaxial vapor deposition of the AlInGaN film on the polar [0001] GaN surface to investigate the influence of the substrate temperature and Al/In ratio on the epitaxial film. Time- and position-dependent boundary constraints were implemented to ensure appropriate growth conditions in the vapor phase region, the near-surface solid, and the bulklike solid region of the growing film. The simulation utilized an optimized Stillinger–Weber potential to describe the interactions among Al–In–Ga–N atoms. For the compositional study, the ratios of Al/In used are 1/9, 3/7, 1/1, 7/3, and 9/1. To investigate the temperature effect on the substrate, four different growth temperatures above half of the simulated melting temperature of the GaN substrate were employed. Following the growth of the AlInGaN film, surface roughness, domain structure, crystallinity, and dislocations were analyzed. Our findings indicate that surface roughness and crystallinity increase with higher Al/In ratios as well as elevated substrate temperatures. The domain size was also observed to increase with higher Al/In ratios and temperatures. At lower temperatures and low Al/In ratios, islands of different polytypes emerge with a high height-to-width ratio, resulting in a highly polytypic structure. The annealing process following growth significantly improves crystallinity and reduces surface roughness. From the dislocation study, it was observed that the maximum number of dislocation lines is of type 1/3[11¯00], which relieve the lattice mismatch strain along the x- and y-directions, and dislocations are minimized at 2500 K. The observed trends in the effects of temperature and the Al-to-In content ratio on dislocations, voids, surface roughness, and domain boundary structures closely resemble known experimental observations in AlInGaN/GaN.

Caspase-8 promotes innate immunity in the Chinese mitten crab by regulating the expression of antimicrobial peptides and apoptosis in hemocyte.

In mammals, caspase-8 primarily functions as an initiator caspase that regulates apoptosis, while in Drosophila, the caspase-8 ortholog DREDD not only induces apoptosis during development but also regulates antimicrobial peptides (AMPs) expression during Gram-negative bacterial infection-induced immune responses. However, the immune-related function of caspase-8 in the crustacean remains unknown. In the present study, the open reading frame of EsCaspase-8 was cloned from the Chinese mitten crab (Eriocheir sinensis). The deduced EsCaspase-8 protein sequence contained only one death effector domain (DED) and a cysteine aspartase cysteine structural domain. The EsCaspase-8 expression was significantly induced after 6 h of Vibrio parahaemolyticus infection and continued to 24 h in hemocyte. Knocking down EsCaspase-8 expression in hemocytes significantly inhibited Relish's nuclear translocation and suppressed the expression of AMPs, including Crustin 1, Crustin 2, Lysosome, and double WAP domain, after V. parahaemolyticus infection. Furthermore, the knockdown of EsCaspase-8 in vivo significantly inhibited hemocyte apoptosis post-bacterial infection. These results demonstrated that EsCaspase-8 can promote antibacterial activities by regulating the expression of AMPs through activation of Relish nuclear translocation in Chinese mitten crabs, thus acting as a critical positive regulator in innate immunity. In addition, EsCaspase-8 also has the function of inducing hemocyte apoptosis. These findings expand our understanding of the molecular mechanisms underlying crustacean immune responses and provide a foundation for future research to improve disease resistance.

The design and development of LRRK2 inhibitors as novel therapeutics for Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disease affecting nearly 10 million people worldwide and placing a heavy medical burden on both society and families. However, due to the complexity of its pathological mechanisms, current treatments for PD can only alleviate patients' symptoms. Therefore, novel therapeutic strategies are urgently sought in clinical practice. Leucine-rich repeat kinase 2 (LRRK2) has emerged as a highly promising target for PD therapy. Missense mutations within the structural domain of LRRK2, the most common genetic risk factor for PD, lead to abnormally elevated kinase activity and increase the risk of developing PD. In this article, we provide a comprehensive overview of the structure, biological function, and pathogenic mutations of LRRK2, and examine recent advances in the development of LRRK2 inhibitors. We hope that this article will provide a reference for the design of novel LRRK2 inhibitors based on summarizing the facts and elucidating the viewpoints.

Genome-Wide Identification and Expression Analysis of NAC Gene Family Members in Seashore Paspalum Under Salt Stress.

The NAC gene family plays a crucial role in plant growth, development, and responses to biotic and abiotic stresses. Paspalum Vaginatum, a warm-season turfgrass with exceptional salt tolerance, can be irrigated with seawater. However, the NAC gene family in seashore paspalum remains poorly understood. In this study, genome-wide screening and identification were conducted based on the NAC (NAM) domain hidden Markov model in seashore paspalum, resulting in the identification of 168 PvNAC genes. A phylogenetic tree was constructed, and the genes were classified into 18 groups according to their topological structure. The physicochemical properties of the PvNAC gene family proteins, their conserved motifs and structural domains, cis-acting elements, intraspecific collinearity analysis, GO annotation analysis, and protein-protein interaction networks were analyzed. The results indicated that the majority of PvNAC proteins are hydrophilic and predominantly localized in the nucleus. The promoter regions of PvNACs are primarily enriched with light-responsive elements, ABRE motifs, MYB motifs, and others. Intraspecific collinearity analysis suggests that PvNACs may have experienced a large-scale gene duplication event. GO annotation indicated that PvNAC genes were essential for transcriptional regulation, organ development, and responses to environmental stimuli. Furthermore, the protein interaction network predicted that PvNAC73 interacts with proteins such as BZIP8 and DREB2A to form a major regulatory hub. The transcriptomic analysis investigates the expression patterns of NAC genes in both leaves and roots under varying durations of salt stress. The expression levels of 8 PvNACs in roots and leaves under salt stress were examined and increased to varying degrees under salt stress. The qRT-PCR results demonstrated that the expression levels of the selected genes were consistent with the FPKM value trends observed in the RNA-seq data. This study established a theoretical basis for understanding the molecular functions and regulatory mechanisms of the NAC gene family in seashore paspalum under salt stress.

Switching processes and ferroelectric hysteresis in dense and porous piezoceramics of the lead zirconate-titanate system

The features of switching processes and electromechanical hysteresis in porous piezoceramics of the lead zirconate-titanate system are studied in comparison with dense piezoceramics of the same composition. It was shown that the differences in switching behavior between dense and porous piezoceramics are due to the specific features of the domain structure and microstructure of porous piezoceramics.

Effect of deformation on magnetic properties of Heusler alloys

Magnetic properties of Heusler alloys with the Ni54.4Mn17.6Ga26.2Si1.8 composition subjected to comprehensive isothermal forging have been investigated. It was found that comprehensive isothermal forging leads to a shift in the temperatures of structural and magnetic phase transitions toward low temperatures, a slight decrease in magnetization and magnetocaloric effect, as well as a qualitative change in the magnetic domain structure.

A mechanism of magnetic hysteresis in heterogeneous Gd-Zr-Co-Cu-Fe alloys

The behavior of the (Gd, Zr)(CoCuFe)Z alloys samples in magnetic fields oriented at different angles to their easy magnetization axis has been studied. The angular dependences of magnetization and coercivity were constructed. The hysteresis loops of the two main structural components of the samples were constructed based on images of the domain structure in demagnetizing fields. An analysis of the obtained results was carried out under assumption of the mixed mechanism of hysteresis in these alloy family.

Dielectric behavior of point defects on ferroelectric films for different substrate strains by phase–field simulations

AbstractRelaxor films constructed by doping point defects are widely applied in various fields, including nanoelectromechanical systems, capacitive energy storage, and pyroelectric energy conversion. Despite their broad utility, the underlying mechanisms by which point defects affect the dielectric properties of these films under varying substrate strains remain insufficiently understood. This work employs a phase–field model to explore the influence of point defects on the domain structure and dielectric properties of BaTiO3 and Pb(Zr,Ti)O3 films, with a comparative analysis of their respective responses to different substrate strains. Our results reveal that the domain sizes in both BaTiO3 and Pb(Zr,Ti)O3 films decrease with doping, leading to a transition into a relaxor state. Notably, Pb(Zr,Ti)O3 exhibits a dielectric peak at a lower doping concentration and a more pronounced reduction in dielectric constant, which can be attributed to its smaller domain size and greater susceptibility to phase transitions. As substrate strain increases from −4% to 4%, the dielectric constant initially rises, peaking at zero strain. Moreover, compared with Pb(Zr,Ti)O3, the BaTiO3 relaxor films display a higher dielectric constant, due to a larger proportion of noninitial phases and a more uniform phase structure. These findings provide valuable theoretical insights into the manipulation of substrate strain as a strategy to tailor the dielectric properties of relaxor films.

Microencapsulated single-component epoxies for self-healing of glass fiber reinforced polymers subjected to low-velocity impacts

This study aimed to investigate the potential of self-healing single-component epoxy microcapsules for improving the impact resistance and durability of glass fiber-reinforced polymer (GFRP) composites. Microcapsules containing a single-component epoxy resin were synthesized using sodium lauryl sulfate and polyvinyl alcohol as stabilizing agents. The microcapsules were characterized, revealing an average size of 3.056 μm. GFRP composites embedded with 10 wt% of the synthesized microcapsules were prepared. The composites were subjected to low-velocity impacts at velocities of 3 m/s, 3.5 m/s, and 4 m/s. Residual flexural properties were evaluated using three-point bending tests. The impact resistance and self-healing efficiency of the GFRP composites showed significant improvement. The flexural after-impact strength exhibited considerable recovery post-impact. A healing efficiency of 61.1% was observed for specimens impacted at a velocity of 3 m/s. Incorporating microcapsules loaded with healing agents transforms GFRP composites into smart materials. The microcapsules act as microscopic primers, rupturing upon damage and releasing the healing agent to mitigate crack propagation and bolster structural integrity autonomously by extending the service life of the composite. The research provides valuable insights into optimizing the performance and durability of GFRP composites. Potential applications span across aerospace, automotive, and structural engineering domains.

Charge-Density-Wave Control by Adatom Manipulation and Its Effect on Magnetic Nanostructures.

Charge-density waves (CDWs) are correlated states of matter, in which the electronic density is modulated periodically due to electronic and phononic interactions. Often, CDW phases coexist with other correlated states, such as superconductivity, spin-density waves, or Mott insulators. Controlling CDW phases may, therefore, enable the manipulation of the energy landscape of these interacting states. The transition metal dichalcogenide 2H-NbSe2 hosts both CDW order and superconductivity, with the incommensurate CDW phase resulting in different CDW-to-lattice alignments at the atomic scale. Using scanning tunneling microscopy, we position adatoms on the surface to induce reversible CDW domain switching. We show that the domain structure critically affects other local interactions, particularly the hybridization of Yu-Shiba-Rusinov states, which emerge from exchange interactions of magnetic Fe atoms with the superconductor. Our results suggest that CDW manipulation could also be used to introduce domain walls into coupled spin chains on superconductors, potentially impacting topological superconductivity.

Adaptive Centroid-Connected Structure Matching Network Based on Semi-Supervised Heterogeneous Domain

Heterogeneous domain adaptation (HDA) utilizes the knowledge of the source domain to model the target domain. Although the two domains are semantically related, the problem of feature and distribution differences in heterogeneous data still needs to be solved. Most of the existing HDA methods only consider the feature or distribution problem but do not consider the geometric semantic information similarity between the domain structures, which leads to a weakened adaptive performance. In order to solve the problem, a centroid connected structure matching network (CCSMN) approach is proposed, which firstly maps the heterogeneous data into a shared public feature subspace to solve the problem of feature differences. Secondly, it promotes the overlap of domain centers and nodes of the same category between domains to reduce the positional distribution differences in the internal structure of data. Then, the supervised information is utilized to generate target domain nodes, and the geometric structural and semantic information are utilized to construct a centroid-connected structure with a reasonable inter-class distance. During the training process, a progressive and integrated pseudo-labeling is utilized to select samples with high-confidence labels and improve the classification accuracy for the target domain. Extensive experiments are conducted in text-to-image and image-to-image HDA tasks, and the results show that the CCSMN outperforms several state-of-the-art baseline methods. Compared with state-of-the-art HDA methods, in the text-to-image transfer task, the efficiency has increased by 8.05%; and in the image-to-image transfer task, the efficiency has increased by about 2%, which suggests that the CCSMN benefits more from domain geometric semantic information similarity.

A Squaramide-Crown Ether-Based Receptor and Polymer for Enhanced Lithium Chloride Extraction.

A non-mulitmacrocyclic ion pair receptor with the ability to cooperatively bind lithium cations and halide anions is presented. These receptors feature a squaramide function for anion binding and are directly linked to a benzo-4-crown-12 unit to achieve selectivity toward lithium salts. Ion pair receptors 1 and 3 demonstrated stronger anion binding in the presence of cobound cations, while anion receptor 2 lacks this property. X-ray measurements supported the simultaneous binding capability of ion pair receptors for both cations and anions. Under solid-liquid extraction (SLE) conditions in acetonitrile, ion pair receptors 1 and 3 selectively extract lithium salts. The more lipophilic receptor 1 can extract LiCl in liquid-liquid extraction (LLE) and SLE, with the latter process notably more selective and effective. Improved LLE extraction of lithium chloride was achieved using copolymer 5 containing receptor units in the structure. The inability of receptor 2 or benzo-12-crown-4 ether to extract salts is attributed to the absence of a heteroditopic binding domain in their structures. This underscores the significant influence of both anion and cation binding domains in the receptor structures on the effective and selective extraction of lithium halide salts. The selectivity of these receptors and the polymeric material toward lithium salts suggests significant potential for extracting lithium from brine solutions with elevated halide content.

MolNexTR: a generalized deep learning model for molecular image recognition

In the field of chemical structure recognition, the task of converting molecular images into machine-readable data formats such as SMILES string stands as a significant challenge, primarily due to the varied drawing styles and conventions prevalent in chemical literature. To bridge this gap, we proposed MolNexTR, a novel image-to-graph deep learning model that collaborates to fuse the strengths of ConvNext, a powerful Convolutional Neural Network variant, and Vision-TRansformer. This integration facilitates a more detailed extraction of both local and global features from molecular images. MolNexTR can predict atoms and bonds simultaneously and understand their layout rules. It also excels at flexibly integrating symbolic chemistry principles to discern chirality and decipher abbreviated structures. We further incorporate a series of advanced algorithms, including an improved data augmentation module, an image contamination module, and a post-processing module for getting the final SMILES output. These modules cooperate to enhance the model’s robustness to diverse styles of molecular images found in real literature. In our test sets, MolNexTR has demonstrated superior performance, achieving an accuracy rate of 81–97%, marking a significant advancement in the domain of molecular structure recognition.Scientific contributionMolNexTR is a novel image-to-graph model that incorporates a unique dual-stream encoder to extract complex molecular image features, and combines chemical rules to predict atoms and bonds while understanding atom and bond layout rules. In addition, it employs a series of novel augmentation algorithms to significantly enhance the robustness and performance of the model.

Transcriptomic analysis reveals three important carbohydrate-active enzymes contributing to starch degradation of oleaginous yeast Lipomyces starkeyi.

The oleaginous yeast Lipomyces starkeyi has a high capacity for starch assimilation, but the genes involved and specific mechanisms in starch degradation remain unclear. This study aimed to identify the critical carbohydrate-active enzyme (CAZyme) genes contributing to starch degradation in L. starkeyi. Comparative transcriptome analysis of cells cultured in glucose and soluble starch medium revealed that 55 CAZymes (including transcript IDs 3772, 1803, and 7314) were highly expressed in soluble starch medium. Protein domain structure and disruption mutant analyses revealed that 3772 encodes the sole secreted α-amylase (LsAmy1p), whereas 1803 and 7314 encode secreted α-glucosidase (LsAgd1p and LsAgd2p, respectively). Triple-gene disruption exhibited severely impaired growth in soluble starch, dextrin, and raw starch media, highlighting their critical role in degrading polysaccharides composed of glucose linked by α-1,4-glucosidic bonds. This study provided insights into the complex starch degradation mechanism in L. starkeyi.