Search Results (206)

4,6-Diamino-1,3,5-triazine (DT) derivatives typically exhibit excellent liquid crystal properties, attracting numerous researchers interested in enhancing their performance. In this paper, two DT molecules (DT−10 and DT−12) are employed to elucidate the effects of their backbone length and number of branches in the tail chains on self-assembled nanostructures using scanning tunneling microscopy (STM) at the 1-octanoic acid/highly ordered pyrolytic graphite interface, compared to our previous report (2TDT−n, n = 10,12,16,18). DT−10 features a short backbone and a trialkoxy chain tail, whereas DT−12 possesses a long backbone and bifurcated chain tails. STM results reveal that DT−10 assembles into a cross-shaped nanostructure with DT head groups arranged in a head-to-head configuration stabilized by a pair of N–H···N hydrogen bindings (HBs). In contrast, DT−12 assembles into a two-row linear pattern, where DT head groups exhibit a side-by-side arrangement mediated by a pair of N–H···N HBs. Comparison with our previous findings indicates that although variations in backbone length and tail chain branching can modulate the nanostructural features of DT derivatives, the chain length of DT molecules emerges as a pivotal factor governing their assembly architecture. Full article

We address the challenge that occlusions in on-branch soybean images impede accurate pod-level phenotyping. We propose a lab on-branch pipeline that couples a prior-guided synthetic data generator (producing synchronized visible and amodal labels) with an amodal instance segmentation framework based on an improved Swin Transformer backbone with a Simple Attention Module (SimAM) and dual heads, trained via three-stage transfer (synthetic excised → synthetic on-branch → few-shot real). Guided by complete (amodal) masks, a morphology-driven module performs pose normalization, axial geometric modeling, multi-scale fused density mapping, marker-controlled watershed, and topological consistency refinement to extract seed per pod (SPP) and geometric traits. On real on-branch data, the model attains Visible Average Precision (AP) 50/75 of 91.6/77.6 and amodal AP50/75 of 90.1/74.7, and incorporating synthetic data yields consistent gains across models, indicating effective occlusion reasoning. On excised pod tests, SPP achieves a mean absolute error (MAE) of 0.07 and a root mean square error (RMSE) of 0.26; pod length/width achieves an MAE of 2.87/3.18 px with high agreement (R² up to 0.94). Overall, the co-designed data–model–task pipeline recovers complete pod geometry under heavy occlusion and enables non-destructive, high-precision, and low-annotation-cost extraction of key traits, providing a practical basis for standardized laboratory phenotyping and downstream breeding applications. Full article

A series of PTT-b-PTMG copolyesters was synthesized via direct esterification followed by melt polycondensation using purified terephthalic acid (PTA), bio-based 1,3-propanediol (PDO), and poly(tetramethylene glycol) (PTMG) of varying molecular weights (650–3000 g/mol). The resulting materials were comprehensively characterized in terms of chemical structure, molecular weight, thermal behavior, phase morphology, crystalline architecture, and mechanical performance using a range of analytical techniques: Fourier-transform infrared spectroscopy (FTIR), ¹H-NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), dynamic mechanical thermal analysis (DMA), tensile testing, and other standard physical methods. FTIR, ¹H-NMR, and GPC data confirmed the successful incorporation of both PTT-hard and PTMG-soft segments into the copolymer backbone. As the PTMG molecular weight increased, the average sequence length of the PTT-hard segments (L_n,T) also increased, leading to higher melting (T_m) and crystallization (T_c) temperatures, albeit with a slight reduction in overall crystallinity. DMA results indicated enhanced microphase separation between hard and soft domains with increasing PTMG molecular weight. WAXS and SAXS analyses further revealed that the crystalline structure and long-range ordering were strongly dependent on the copolymer composition and block architecture. Mechanical testing showed that tensile strength at break remained relatively constant across the series, while Young’s modulus increased significantly with higher PTMG molecular weight—concurrently accompanied by a decrease in elongation at break. Furthermore, the elastic deformability and recovery behavior of PTT-b-PTMG block copolymers were evaluated through cyclic tensile testing. TGA confirmed that all copolyesters exhibited excellent thermal stability. This study demonstrates that the physical and mechanical properties of bio-based PTT-b-PTMG elastomers can be effectively tailored by adjusting the molecular weight of the PTMG-soft segment, offering valuable insights for the rational design of sustainable thermoplastic elastomers with tunable performance. Full article

Bottle-brush polymers with aggrecan-like side chains represent a class of biomimetic macromolecules that replicate key structural and functional features of natural complexes of aggrecans with hyaluronic acid (HA) which are the major components of articular cartilage. In this study, we employ numerical self-consistent field (SCF) modeling combined with analytical theory to investigate the conformational properties of cylindrical molecular bottle-brushes composed of aggrecan-like double-comb side chains tethered to the main chain (the backbone of the bottle-brush). We demonstrate that the architecture of the brush-forming double-comb chains and, in particular, the distribution of polymer mass between the root and peripheral domains significantly influences the spatial distribution of primary side chain ends, leading to formation of a “dead” zone near the backbone of the bottle-brush and non-uniform density profiles. The axial stretching force imposed by grafted double-combs in the main chain, as well as normal force acting at the junction point between the bottle-brush backbone and the double-comb side chain are shown to depend strongly on the side-chain architecture. Furthermore, we analyze the induced bending rigidity and persistence length of the bottle-brush, revealing that while the overall scaling behavior follows established power laws, the internal structure can be finely tuned without altering the backbone stiffness. These theoretical findings provide valuable insights into relations between architecture and properties of bottle-brush-like supra-biomolecular structures, such as aggrecan-hyaluronan complexes. Full article

Oral administration remains the most patient-friendly drug delivery route, yet its efficacy is limited by physiological barriers including gastric degradation and inefficient cellular uptake. pH-responsive nanogels have shown promise for gastrointestinal drug delivery, though their effectiveness is often constrained by poor membrane interaction. Inspired by natural membrane-anchoring mechanisms, a series of comb-like anionic polymers were designed via grafting alkylamines of different chain lengths (C₁₀, C₁₄, C₁₈) at varying densities (10–30%) onto a biodegradable poly(L-lysine isophthalamide) (PLP) backbone. These pH-responsive comb-like polymers self-assembled into nanogels for loading the hydrophobic chemotherapeutic agent camptothecin. The alkyl length and grafting density significantly influenced pH-responsive behavior, membrane disruption, and drug release profiles. The optimal formulation—the nanogel prepared with PLP grafted 30% C₁₄—achieved a high drug-loading capacity, ideal particle size and stability, and offered superior protection in acidic conditions (only 7 ± 5% release at pH 1.2 over 24 h), while enabling rapid intestinal release (78 ± 2% at pH 7.4 within 24 h). The nanogels significantly enhanced cellular uptake, cytoplasmic delivery, and cytotoxicity against colorectal carcinoma cells. This study demonstrates the key role of hydrophobic modification in designing effective oral nanocarriers, providing a promising platform for the treatment of intestinal diseases. Full article

Transformer-based 2D-to-3D lifting methods have demonstrated outstanding performance in 3D human pose estimation from 2D pose sequences. However, they still encounter challenges with the relatively poor quality of 2D joints and substantial computational costs. In this paper, we propose a CGFusionFormer to address these problems. We propose a compact spatial representation (CSR) to robustly generate local spatial multihypothesis features from part of the 2D pose sequence. Specifically, CSR models spatial constraints based on body parts and incorporates 2D Gaussian filters and nonparametric reduction to improve spatial features against low-quality 2D poses and reduce the computational cost of subsequent temporal encoding. We design a residual-based Hybrid Adaptive Fusion module that combines multihypothesis features with global frequency domain features to accurately estimate the 3D human pose with minimal computational cost. We realize CGFusionFormer with a PoseFormer-like transformer backbone. Extensive experiments on the challenging Human3.6M and MPI-INF-3DHP benchmarks show that our method outperforms prior transformer-based variants in short receptive fields and achieves a superior accuracy–efficiency trade-off. On Human3.6M (sequence length 27, 3 input frames), it achieves 47.6 mm Mean Per Joint Position Error (MPJPE) at only 71.3 MFLOPs, representing about a 40 percent reduction in computation compared with PoseFormerV2 while attaining better accuracy. On MPI-INF-3DHP (81-frame sequences), it reaches 97.9 Percentage of Correct Keypoints (PCK), 78.5 Area Under the Curve (AUC), and 27.2 mm MPJPE, matching the best PCK and achieving the lowest MPJPE among the compared methods under the same setting. Full article

Substituting cement with mineral additives like fly ash is increasingly essential for sustainable production. While replacement rates largely depend on fresh-state properties, the interaction between fly ash and polycarboxylate ether (PCE) molecular structures remains underexplored. In this regard, this study investigates the effect of PCE molecular structures and weight on the rheology, setting, and strength of cementitious systems containing up to 45% fly ash additions. Seven distinct PCE possessing different molecular weights (27,000–78,000 g/mol) as well as backbone and side chain lengths are synthesized. The interaction between PCE and solid particles was explored through total organic carbon, dynamic light scattering, and gel permeation chromatography. Test results showed that the adsorption rates of the cement and fly ash particles within the cementitious composites improved by up to 90% with fly ash replacement and upon using PCE with a medium molecular weight of 56,000 g/mol, backbone length of 21 k, and short side chain length of 1000 g/mol. This has resulted in a 75% reduction in the material’s apparent viscosity, delayed setting times of up to 38%, and improved early- and late-age compressive strengths of up to 123%. Such data can interest cement and admixture producers in proposing suitable PCEs for superior fly ash concrete performance. Full article

G8 rotaviruses are primarily associated with animals and infrequently cause infections in humans. The first detection of G8 strains in humans occurred around 1979, and since then, their presence has been sporadic, particularly in the United States (U.S.). During the 2016–2017 rotavirus surveillance season, the New Vaccine Surveillance Network (NVSN) identified 36 G8P[8] rotavirus strains across four sites in the U.S. This study presents the whole-genome characterization of these G8P[8] strains, along with comparative sequence analyses against the current vaccine strains, Rotarix and RotaTeq. Each strain exhibited a DS-1-like backbone with a consensus genotype constellation of G8P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 and exhibited high genetic similarities to G8P[8] strains previously detected in Europe and Asia. Clinical analysis revealed no significant differences in hospitalization rates, length of stay, or severity scores between G8P[8] RVA-positive and non-G8P[8] RVA-positive subjects. Additionally, phylodynamic analysis determined the evolutionary rates and the most recent common ancestor for these strains, highlighting the importance of ongoing monitoring of rotavirus genotypes to assess the spread of these emerging G8P[8] strains. Full article

Staphylococcus aureus is the most common pathogen causing osteomyelitis, a hardly recoverable bone infection that generates significant burden to patients. Osteomyelitis mouse models have long and successfully served to provide phenomenological insights into both pathogenesis and host response. However, direct in situ monitoring of bone microbial pathogenesis and immune response at the cellular level is still conspicuously missing in the published literature. Here, we update a standard pyogenic osteomyelitis in Wistar rat model, in order to investigate bacterial localization and immune response in osteomyelitis of rat tibia upon adding in situ analyses by spectrally resolved Raman spectroscopy. Raman experiments were performed one and five weeks post infections upon increasing the initial dose of bacterial inoculation in rat tibia. Label-free in situ Raman spectroscopy clearly revealed the presence of Staphylococcus aureus through exploiting peculiar signals from characteristic carotenoid staphyloxanthin molecules. Data were collected as a function of both initial bacteria inoculation dose and location along the tibia. Such strong Raman signals, which relate to single and double bonds in the carbon chain backbone of carotenoids, served as efficient bacterial markers even at low levels of infection. We could also detect strong Raman signals from cytochrome c (and its oxidized form) from bone cells in response to infection and inflammatory paths. Although initial inoculation was restricted to a single location close to the medial condyle, bacteria spread along the entire bone down to the medial malleolus, independent of initial infection dose. Raman spectroscopic characterizations comprehensively and quantitatively revealed the metabolic state of bacteria through specific spectroscopic biomarkers linked to the length of staphyloxanthin carbon chain backbone. Moreover, the physiological response of eukaryotic cells could be quantified through monitoring the level of oxidation of mitochondrial cytochrome c, which featured the relative intensity of the 1644 cm⁻¹ signal peculiar to the oxidized molecules with respect to its pyrrole ring-breathing signal at 750 cm⁻¹, according to the previously published literature. In conclusion, we present here a novel Raman spectroscopic approach indexing bacterial concentration and immune response in bone tissue. This new approach enables locating and characterizing in situ bone infections, inflammatory host tissue reactions, and bacterial resistance/adaptation. Full article

A modular strategy for the molecular design of silicone-based antifoaming agents was developed by precisely controlling the architecture of poly (methylhydrosiloxane) (PMHS). Sixteen PMHS variants were synthesized by systematically varying the siloxane chain length (L1–L4), backbone composition (D₃T₁ vs. D₃₀T₁), and terminal group chemistry (H- vs. M-type). These structural modifications resulted in a broad range of Si-H functionalities, which were quantitatively analyzed and correlated with defoaming performance. The PMHS matrices were integrated with high-viscosity PDMS, a nonionic surfactant, and covalently grafted fumed silica—which was chemically matched to each PMHS backbone—to construct formulation-specific defoaming systems with enhanced interfacial compatibility and colloidal stability. Comprehensive physicochemical characterization via FT-IR, ¹H NMR, GPC, TGA, and surface tension analysis revealed a nonmonotonic relationship between Si-H content and defoaming efficiency. Formulations containing 0.1–0.3 wt% Si-H achieved peak performance, with suppression efficiencies up to 96.6% and surface tensions as low as 18.9 mN/m. Deviations from this optimal range impaired performance due to interfacial over-reactivity or reduced mobility. Furthermore, thermal stability and molecular weight distribution were found to be governed by repeat unit architecture and terminal group selection. Compared with conventional EO/PO-modified commercial defoamers, the PMHS-based systems exhibited markedly improved suppression durability and formulation stability in high-viscosity environments. These results establish a predictive structure–property framework for tailoring antifoaming agents and highlight PMHS-based formulations as advanced foam suppressors with improved functionality. This study provides actionable design criteria for high-performance silicone materials with strong potential for application in thermally and mechanically demanding environments such as coating, bioprocessing, and polymer manufacturing. Full article

Using density functional theory (M06-2X-D3/def2-TZVP), we investigated the 1,2-addition reactions of NH₃ with a series of heavy imine analogues, G13=P-Rea (where G13 denotes a Group 13 element; Rea = reactant), featuring a mixed G13–P–Ga backbone. Theoretical analyses revealed that the bonding nature of the G13=P moiety in G13=P-Rea molecules varies with the identity of the Group 13 center. For G13=B, Al, Ga, and In, the bonding is best described as a donor–acceptor (singlet–singlet) interaction, whereas for G13=Tl, it is characterized by an electron-sharing (triplet–triplet) interaction. According to our theoretical studies, all G13=P-Rea species—except the Tl=P analogue—undergo 1,2-addition with NH₃ under favorable energetic conditions. Energy decomposition analysis combined with natural orbitals for chemical valence (EDA–NOCV), along with frontier molecular orbital (FMO) theory, reveals that the primary bonding interaction in these reactions originates from electron donation by the lone pair on the nitrogen atom of NH₃ into the vacant p-π* orbital on the G13 center. In contrast, a secondary, weaker interaction involves electron donation from the phosphorus lone pair of the G13=P-Rea species into the empty σ* orbital of the N–H bond in NH₃. The calculated activation barriers are primarily governed by the deformation energy of ammonia. Specifically, as the atomic weight of the G13 element increases, the atomic radius and G13–P bond length also increase, requiring a greater distortion of the H₂N–H bond to reach the transition state. This leads to a higher geometrical deformation energy of NH₃, thereby increasing the activation barrier for the 1,2-addition reaction involving these Lewis base-stabilized, heavy imine-like G13=P-Rea molecules and ammonia. Full article

Optical networks serve as the backbone of modern communication, requiring statistical analysis and modeling to optimize performance, reliability, and scalability. This review paper explores statistical methodologies for analyzing network characteristics, dimensioning, parameter estimation, and cost prediction of optical networks, and provides a generalized framework based on the idea of convex areas, and link length and shortest path length distributions. Accurate dimensioning and cost estimation are crucial for optical network planning, especially during early-stage design, network upgrades, and optimization. However, detailed information is often unavailable or too complex to compute. Basic parameters like coverage area and node count, along with statistical insights such as distribution patterns and moments, aid in determining the appropriate modulation schemes, compensation techniques, repeater placement, and in estimating the fiber length. Statistical models also help predict link lengths and shortest path lengths, ensuring efficiency in design. Probability distributions, stochastic processes, and machine learning improve network optimization and fault prediction. Metrics like bit error rate, quality of service, and spectral efficiency can be statistically assessed to enhance data transmission. This paper provides a review on statistical analysis and modeling of optical networks, which supports intelligent optical network management, dimensioning of optical networks, performance prediction, and estimation of important optical network parameters with partial information. Full article

In cybersecurity, constructing an accurate knowledge graph is vital for discovering key entities and relationships in security incidents buried in vast unstructured threat reports. Traditional knowledge-graph construction pipelines based on handcrafted rules or conventional machine learning models falter when the data scale and linguistic variety grow. GraphRAG, a retrieval-augmented generation (RAG) framework that splits documents into fixed-length chunks and then retrieves the most relevant ones for generation, offers a scalable alternative yet still suffers from fragmentation and semantic gaps that erode graph integrity. To resolve these issues, this paper proposes SC-LKM, a cybersecurity knowledge-graph construction method that couples the GraphRAG backbone with hierarchical semantic chunking. SC-LKM applies semantic chunking to build a cybersecurity knowledge graph that avoids the fragmentation and inconsistency seen in prior work. The semantic chunking method first respects the native document hierarchy and then refines boundaries with topic similarity and named-entity continuity, maintaining logical coherence while limiting information loss during the fine-grained processing of unstructured text. SC-LKM further integrates the semantic comprehension capacity of Qwen2.5-14B-Instruct, markedly boosting extraction accuracy and reasoning quality. Experimental results show that SC-LKM surpasses baseline systems in entity-recognition coverage, topology density, and semantic consistency. Full article

In our previous studies, methylated CpG oligodeoxynucleotides (ODN) derived from Bifidobacterium longum subsp. infantis have demonstrated immunomodulatory effects through the induction of regulatory T cells (Tregs). To define the structural determinants underlying this effect, we synthesized four CpG ODNs varying in methylation degree, CpG motif placement, and backbone length. These include (1) ODN-A (2m-V1), a 20-nucleotide CpG oligodeoxynucleotide incorporating two 5-methylcytosines at positions 4 and 12 within centrally placed CpG motifs; (2) ODN-B (um-V2), a 20-nucleotide CpG oligodeoxynucleotide with a backbone structure identical to ODN-A but unmethylated; (3) ODN-C (2m’-V3), a 20-nucleotide CpG oligodeoxynucleotide with a backbone structure identical to ODN-A, but with two 5-methylcytosines shifted to positions 7 and 15; (4) ODN-D (3m-V4), a 27-nucleotide CpG oligodeoxynucleotide with an extended backbone structure, this time with three 5-methylcytosines at positions 3, 11, and 19. Using a murine model of an OVA-induced allergy, we show that methylated ODN-A (2m-V1) and ODN-D (3m-V4) markedly reduce serum anti-OVA IgE, clinical symptoms, eosinophilic infiltration, and Th2/Th17 responses, while promoting splenic Treg expansion and IL-10 production. In contrast, unmethylated ODN-B (um-V2) and a positionally altered methylated ODN-C (2m’-V3) both failed to suppress allergic inflammation, and, in contrast, enhanced the Th2/Th17 response and induced robust in vitro Toll-like receptors TLR7/8/9 expression in native splenocytes. These findings suggest that both methylation and motif architecture critically influence the immunologic profile of CpG ODNs. Our results provide mechanistic insights into CpG ODN structure/function relationships and support the therapeutic potential of select methylated sequences for restoring immune tolerance in allergic diseases. Full article

Combining Brownian dynamics simulations and self-consistent field theory, we demonstrate that stable assembled structures, such as vesicles, toroidal micelles, bowl-like micelles, sheet-like micelles, non-spherical vesicles, and cylindrical micelles, are dependent on the molecular parameters of amphiphilic comb-like copolymers. Importantly, we find that vesicle formation involves two intermediate states, sheet-like and bowl-like micelles, and the difference in their free energies is minimal, which illustrates the coexisting phase between them. Moreover, the assembled vesicles can be modulated in the membrane thickness with overall size, unchanged only by adjusting the backbone length. We also demonstrate the coexistence of toroidal and cylindrical micelles because neither structure has a significant advantage over the other in free energy. Our work points out how to obtain different morphologies by adjusting the molecular parameters of amphiphilic comb-like copolymers, instilling confidence in their potential for stable drug encapsulation and enhanced targeted drug delivery. Full article