jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Shiyang Ji | Yuying Du | Jiancai Leng | Yujin Zhang | Wei Hu
Source: International Journal of Molecular Sciences (article, 2024-11-18)
Field: Materials Science — Materials Chemistry

Planar-Twisted Molecular Engineering for Modulating the Fluorescence Brightness of NIR-II Fluorophores with a Donor–Acceptor–Donor Skeleton Organic molecular fluorophores have been extensively utilized for biological imaging in the visible and the first near-infrared windows. However, their applications in the second near-infrared (NIR-II) window remain constrained, primarily due to the insufficient fluorescence brightness. Herein, we employ a theoretical protocol combining the thermal vibration correlation function with the time-dependent density functional theory method to investigate the mechanism of the planar-twisted strategy for developing fluorophores with balanced NIR-II emission and fluorescence brightness. Based on a planar donor-acceptor-donor molecular skeleton, various ortho-positioned alkyl side chains with steric hindrances are tactfully incorporated into the backbone to construct a series of twisted fluorophores. Photophysical characterizations of the studied fluorophores demonstrate that the emission spectra located in the NIR-II region exhibited a hypsochromic shift with the structural distortion. Notably, conformational twisting significantly accelerated the radiative decay rate while simultaneously suppressing the nonradiative decay rate, resulting in an improved fluorescence quantum efficiency (FQE). This enhancement can be mainly attributed to both the enlarged adiabatic excitation energy and reduced nonadiabatic electronic coupling between the first excited state and the ground state. Compared with the planar fluorophore, the twisted structures possessed a more than fivefold increase in FQE. In particular, the optimal twisted fluorophore BBTD-4 demonstrated a desirable fluorescence brightness (16.59 M<sup>-1</sup> cm<sup>-1</sup>) on the premise of typical NIR-II emission (980 nm), making it a promising candidate for NIR-II fluorescence imaging in biomedical applications. The findings in this study elucidate the available experimental observations on the analogues, highlighting a feasible approach to modulating the photophysical performances of NIR-II chromophores for developing more highly efficient fluorophores toward optical imaging applications. Fluorescence ; Skeleton (computer programming) ; Brightness ; Acceptor ; Chemistry ; Planar ; Photochemistry ; Biophysics ; Materials science ; Anatomy ; Biology ; Computer science ; Optics ; Physics ; Computer graphics (images) Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Molecular Sensors and Ion Detection
Authors: Krishna Puri | Suvarn S. Kulkarni
Source: Communications Chemistry (article, 2024-09-12)
Field: Chemistry — Organic Chemistry

Total synthesis of a structurally complex zwitterionic hexasaccharide repeating unit of polysaccharide B from Bacteroides fragilis via one-pot glycosylation Zwitterionic polysaccharides (ZPSs) present on the surface of a common gut commensal Bacteroides fragilis are endowed with unique immunological properties as they can directly bind to T-cells in the absence of protein conjugation. ZPSs are therefore considered to be potential antigens for the development of totally carbohydrate-based vaccines. Herein, we disclose the first total synthesis of a highly branched phosphorylated zwitterionic capsular polysaccharide repeating unit of Bacteroides fragilis. The hexasaccharide repeating unit bearing six different monosaccharides comprises three 1,2-cis-glycosidic linkages, a challenging 1,2-trans linkage in D-QuipNAc-β-(1→4)-D-Gal motif, and a 2-aminoethyl phosphonate appendage. The synthesis of target ZPS was accomplished utilizing an expeditious, highly stereoselective and convergent (1 + 2 + 2 + 1) one-pot glycosylation strategy. The striking features include efficient synthesis of rare deoxy amino sugars D- and L-quinovosamine, stereoselective installation of three 1,2-cis glycosidic linkages, glycosylation of D-quinovosamine donor with a sterically crowded, poorly reactive 4-OH galactose moiety, as well as late stage phosphorylation. Bacteroides fragilis ; Glycosylation ; Chemistry ; Stereochemistry ; Glycosidic bond ; Phosphonate ; Moiety ; Pilin ; Stereoselectivity ; Biochemistry ; Monosaccharide ; Polysaccharide ; Glycan ; Pilus ; Glycoprotein ; Gene ; Escherichia coli ; Antibiotics ; Catalysis ; Enzyme Carbohydrate Chemistry and Synthesis ; Glycosylation and Glycoproteins Research ; Probiotics and Fermented Foods
Authors: Souvik Ghosh | Partha Roy | Debrupa Lahiri
Source: Chemistry - An Asian Journal (article, 2024-03-28)
Field: Materials Science — Biomaterials

Development of Anisotropic Electrically Conductive GNP‐Reinforced PCL‐Collagen Scaffold for Enhanced Neurogenic Differentiation under Electrical Stimulation The internal electric field of the human body plays a crucial role in regulating various biological processes, such as, cellular interactions, embryonic development and the healing process. Electrical stimulation (ES) modulates cytoskeleton and calcium ion activities to restore nervous system functioning. When exposed to electrical fields, stem cells respond similarly to neurons, muscle cells, blood vessel linings, and connective tissue (fibroblasts), depending on their environment. This study develops cost-effective electroconductive scaffolds for regenerative therapy. This was achieved by incorporating carboxy functionalized graphene nanoplatelets (GNPs) into a Polycaprolactone (PCL)-collagen matrix. ES was used to assess the scaffolds' propensity to boost neuronal differentiation from MSCs. This study reported that aligned GNP-reinforced PCL-Collagen scaffolds demonstrate substantial MSC differentiation with ES. This work effectively develops scaffolds using a simple, cost-effective synthesis approach. The direct coupling approach generated a homogeneous electric field to stimulate cells cultured on GNP-reinforced scaffolds. The scaffolds exhibited improved mechanical and electrical characteristics, as a result of the reinforcement with carbon nanofillers. In vitro results suggest that electrical stimulation helps differentiation of mesenchymal stem-like cells (MSC-like) towards neuronal. This finding holds great potential for the development of effective treatments for tissue injuries related to the nervous system. Scaffold ; Stimulation ; Materials science ; Electrical conductor ; Anisotropy ; Composite material ; Biomedical engineering ; Optoelectronics ; Medicine ; Internal medicine ; Physics Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials ; Bone Tissue Engineering Materials
Authors: Edward Chen | Lih‐Sheng Turng
Source: Polymer Engineering and Science (article, 2024-02-13)
Field: Materials Science — Biomaterials

A <scp>double‐expanded</scp> polytetrafluoroethylene fabrication method for increased mechanical compliance in tubular vascular graft applications A novel manufacturing technique has been developed to enhance the compliance of expanded polytetrafluoroethylene (ePTFE) for vascular graft applications. This new method involves modifying the existing processing procedures by introducing an additional expansion step while using a lower temperature during the first expansion stage. The new process results in the production of highly compliant ePTFE grafts without the need for supplementary additives or inherent material alterations. Tensile testing in both the longitudinal and circumferential directions as well as cyclical tensile testing were conducted to characterize the mechanical properties of double-expanded ePTFE grafts prepared using varying expansion ratios. The double-expanded ePTFE grafts consistently outperformed the prevailing, single-expanded counterparts in both tensile stress tests and cyclical assessments of its elastic compliance. Notably, the double-expanded ePTFE samples exhibited the desirable, biomimetic "toe-region" and an elastic strain capacity of up to 50%, comparable to native vascular materials. Scanning electron microscopy (SEM) imaging was used to examine the morphological characteristics of the wavy fibers within the double-expanded PTFE samples, which contributed to the enhanced compliance that is needed for vascular graft applications. Materials science ; Fabrication ; Compliance (psychology) ; Vascular graft ; Polytetrafluoroethylene ; Biomedical engineering ; Composite material ; Nanotechnology ; Medicine ; Pathology Electrospun Nanofibers in Biomedical Applications ; Aortic Disease and Treatment Approaches ; Cardiac and Coronary Surgery Techniques
Authors: Wei Hao | Simon M.‐M. Dubois | Frederic Brunnett | Julian Peiro | Florian Godel | Cécile Carrétéro | Federico Panciera | Sophie Collin | F. Bouamrane | Victor Zatko | Marta Galbiati | Etienne Carré | G. Patriarche | F. Pétroff | Jean‐Christophe Charlier | Marie‐Blandine Martin | Bruno Dlubak | Pierre Sénéor
Source: Advanced Materials Interfaces (article, 2024-06-18)
Field: Materials Science — Materials Chemistry

Large‐Area Artificial van der Waals “Mille‐Feuille” Superlattices Abstract Van der Waals heterostructures are set as strong contenders for post‐CMOS quantum materials engineering. A major step for their systematic exploration and exploitation of technological component demonstrators resides in their eased large‐scale design. In this direction, the growth of artificial van der Waals 2D superlattices is presented here such as (MoS 2 /WS 2 ) n , (WS 2 /WSe 2 ) n , and (MoS 2 /WSe 2 ) n with unit cells repetitions reaching n &gt; 10. The fabrication of these materials is enabled by a fully automated in‐situ pulsed laser deposition (PLD) tool. This approach provides cm 2 scale homogeneous superlattices with on‐demand material parameters tailoring (layer number, order, and composition). The process is rapid and simple compared to manual pickup exfoliation methods or to sequential transfers of single layers grown by techniques such as chemical vapor deposition, allowing a large repetition of the unit cells in a “mille‐feuille” cake configuration. The computational exploration of this family of superlattice materials sheds light on the potential for optoelectronic property design by shaping the band‐structure landscape while taking into account the influential effects induced by proximity. Overall, this large‐area approach is proposed as an entry point for the systematic design of complex van der Waals heterostructures. van der Waals force ; Superlattice ; Materials science ; Heterojunction ; Nanotechnology ; Chemical vapor deposition ; Deposition (geology) ; Optoelectronics ; Engineering physics ; Chemistry ; Molecule ; Physics 2D Materials and Applications ; MXene and MAX Phase Materials ; Advanced Photocatalysis Techniques
Authors: Johannes Rocker | Till J. B. Zähringer | Matthias Schmitz | Till Opatz | Christoph Kerzig
Source: Beilstein Journal of Organic Chemistry (article, 2024-05-28)
Field: Chemistry — Organic Chemistry

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis Organic photocatalysts frequently possess dual singlet and triplet photoreactivity and a thorough photochemical characterization is essential for efficient light-driven applications. In this article, the mode of action of a polyazahelicene catalyst (Aza-H) was investigated using laser flash photolysis (LFP). The study revealed that the chromophore can function as a singlet-state photoredox catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. The singlet lifetime is sufficiently long to exploit the exceptional excited state reduction potential for the activation of 4-cyanopyridine. Photoinduced electron transfer generating the radical cation was directly observed confirming the previously proposed mechanism of a three-component reaction. Several steps of the photoredox cycle were investigated separately, providing deep insights into the complex mechanism. The triplet-excited Aza-H, which was studied with quantitative LFP, is formed with a quantum yield of 0.34. The pronounced triplet formation was exploited for the isomerization reaction of (<i>E</i>)-stilbene to the <i>Z</i>-isomer and the cyclization of cinnamyl chloride. Catalyst degradation mainly occurs through the long-lived Aza-H triplet (28 µs), but the photostability is greatly increased when the triplet efficiently reacts in a catalytic cycle such that turnover numbers exceeding 4400 are achievable with this organocatalyst. Chemistry ; Photochemistry ; Photoredox catalysis ; Chromophore ; Flash photolysis ; Singlet state ; Catalysis ; Catalytic cycle ; Triplet state ; Electron transfer ; Quantum yield ; Isomerization ; Singlet oxygen ; Cycloisomerization ; Singlet fission ; Excited state ; Photocatalysis ; Reaction rate constant ; Kinetics ; Fluorescence ; Molecule ; Organic chemistry Synthesis and Properties of Aromatic Compounds ; Photochromic and Fluorescence Chemistry ; Radical Photochemical Reactions
Authors: Md Shariful Islam Sozal | Wenhao Li | Suprabha Das | Borzooye Jafarizadeh | Azmal Huda Chowdhury | Chunlei Wang | Zhe Cheng
Source: Materials Advances (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Fabrication and preliminary testing of patterned silver cathodes for proton conducting IT-SOFCs Patterned Ag cathodes are fabricated over a proton conducting electrolyte, and the preliminary electrochemical results suggest that the oxygen reduction process over Ag is likely controlled by both oxygen dissociation and charge transfer. Fabrication ; Cathode ; Materials science ; Proton ; Forensic engineering ; Nanotechnology ; Electrical engineering ; Engineering ; Medicine ; Nuclear physics ; Physics Advancements in Solid Oxide Fuel Cells ; Electronic and Structural Properties of Oxides ; Gas Sensing Nanomaterials and Sensors
Authors: Jiří Demuth | Stefan Bednarik | Radek Macháň | Ivan Mocak | T. V. Malinsky | Mona Abo El Dahab | Jakub Holcak | Miroslav Miletín | Jan Labuta | Veronika Novakova | Petr Zimčík
Source: Inorganic Chemistry Frontiers (article, 2024-12-31)
Field: Materials Science — Materials Chemistry

J-dimers of phthalocyanine analogues: structural characterization and their use for determination of association constants between ligands and the central cation J-dimers of phthalocyanine analogues are disassembled by various coordinating ligands with distinct changes in absorption and emission spectra. Phthalocyanine ; Characterization (materials science) ; Chemistry ; Association (psychology) ; Crystallography ; Materials science ; Nanotechnology ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Free Radicals and Antioxidants ; Molecular Sensors and Ion Detection
Authors: Shuo Li | Bowen Fang | Yan Wang | Fangxin Zou | Jian Zhao | Hong Zhang | Jing Guo | Zhiguo Wang | Jiazhuang Xu
Source: Polymer Composites (article, 2024-11-22)
Field: Materials Science — Materials Chemistry

Three‐dimensional printing of boron nitride platelets/polylactic acid composites: Achieving enhanced through plane thermal conductivity and decent mechanical properties Abstract Thermally conductive polymer composites (TPMCs) hold immense potential, particularly in modern microelectronics thermal management. However, their practical enhancement in thermal performance, in particular the thermal conductivity (TC) in the through plane ( κ ⊥ ), often lags behind theoretical predictions attributable to thermal resistance at the interface and the pivotal dependence of anisotropic filler orientation on thermal conductivity. To harness the full capabilities of TPMCs and overcome thermal management challenges, we developed an innovative strategy focused on achieving optimal filler orientation. Employing 3D printing (FDM) technology, we constructed highly vertically oriented hexagonal boron nitride/Polylactic acid composites by layer‐by‐layer deposition, thereby maximizing the inherent high κ ⊥ of hBN. This innovative composite with highly vertically oriented hBN exhibits significantly enhanced κ ⊥ up to 3.04 Wm −1 K −1 , which is 1348% and 420% enhanced compared to the polylactic acid (PLA) and paralleled counterparts. Scanning electron microscopy and x‐ray diffraction show orientation of hBN in PLA matrix, due to the shearing and squeezing effects of FDM when melting and depositing. Additionally, the tensile strength exhibited by polymer composites is commendable, with all values exceeding 22 MPa. Along with extraordinary thermal management performances and mechanical strength, and the customizability using FDM technology, paves the way for TPMCs to revolutionize thermal management applications. Highlights Constructed the vertically oriented hexagonal boron nitride within the matrix. Dramatically boosted through‐plane TC in the composite. FDM enables the customization of diverse and intricate shapes. Implemented a simple strategy for optimizing composite properties. Achieving balance between thermal conductivity and mechanical properties. Materials science ; Composite material ; Boron nitride ; Polylactic acid ; Thermal conductivity ; Composite number ; Interfacial thermal resistance ; Thermal ; Polymer ; Thermal resistance Thermal properties of materials ; Heat Transfer and Optimization ; Advanced Thermoelectric Materials and Devices
Authors: Aleksandra Świerkula | Leszek Zaraska
Source: Journal of Solid State Electrochemistry (article, 2024-10-22)
Field: Materials Science — Materials Chemistry

Tuning the geometry of porous alumina layers via anodization in mixtures of different acids Abstract Porous anodic aluminum oxide (AAO) layers have been obtained by two-step anodization of high-purity Al in two types of acid mixtures, i.e., in H 2 C 2 O 4 –H 3 PO 4 and, for the first time, in H 2 SO 4 –H 3 PO 4 systems. The kinetics of oxide formation was examined by monitoring the current vs. time curves while the morphology of the resulting layers was carefully verified by scanning electron microscopy (SEM). A special emphasis was put on establishing correlations between electrolyte composition, the kinetics and effectiveness of oxide growth, and the morphological features of AAO layers (pore and cell diameter, porosity), as well as pore arrangement. It was confirmed that the addition of H 3 PO 4 to both H 2 C 2 O 4 and H 2 SO 4 electrolytes results in a significant decrease in oxide growth rate, and worsening of pore arrangement, while the values of pore diameter and interpore distance are much less affected. Moreover, the presence of a small amount of phosphoric acid in the reaction mixture allowed for a noticeable increase in pore ordering if anodization was carried out beyond the self-ordering regime, or performing controlled anodization even at voltages at which the burning phenomenon is typically observed. It is strongly believed that manipulating the electrolyte composition by adding another acid may provide another degree of freedom to control the morphology of the resulting nanostructured alumina layers. Anodizing ; Porosity ; Materials science ; Chemical engineering ; Electrochemistry ; Geometry ; Nanotechnology ; Composite material ; Chemistry ; Aluminium ; Physical chemistry ; Electrode ; Mathematics ; Engineering Anodic Oxide Films and Nanostructures ; Smart Materials for Construction ; Photonic Crystals and Applications
Authors: Mohammad Nur‐E‐Alam | Mohammad Tanvirul Ferdaous | Abdullah Alghafis | Mikhail Vasiliev | Boon Kar Yap | Tiong Sieh Kiong | Megat Mohd Izhar Sapeli | Nowshad Amin | Mohd Adib Ibrahim | Md Khan Sobayel Bin Rafiq
Source: Solar RRL (article, 2024-12-17)
Field: Materials Science — Materials Chemistry

Tailoring Ga‐Doped ZnO Thin Film Properties for Enhanced Optoelectric Device Performance: Argon Flow Rate Modulation and Dynamic Sputtering Geometry Analysis The impact of dynamic sputtering geometry on the properties of ZnO: Ga (GZO) thin film nanomaterials is investigated by systematically varying Ar flow rates and substrate positions during the film growth. The structural, optical, and electrical characteristics of GZO layers, deposited from a ZnO: Ga (5.7 wt%) ceramic‐type sputtering target, are comprehensively evaluated to reveal the relationship between the sputtering geometry and material properties. The obtained electrical properties, comparatively high carrier mobility 11.3 × 10 1 cm 2 V −1 s −1 and the lowest resistivity 1.13 × 10 −3 Ω‐cm, together with a moderately high optoelectric figure of merit with the films prepared using around 6 sccm Ar‐flow rate (corresponding to around 4.92 mTorr Ar partial pressure) reveal distinct correlations between the sputtering conditions and thin film properties, providing insights into the optimization of sputtering parameters for tailored material synthesis required for advanced and emerging applications. The GZO thin film (prepared with the optimal setting of 6 sccm Ar flow rate) exhibits remarkable optoelectronic capabilities as a transport layer in solar cells, reaching peak efficiencies of 26.34% for CIGS, 14.142% for CdTe, and 24.289% for Cs 2 AgBiBr 6 perovskite in SCAPS‐1D simulated models. This study advances sputtering techniques for precise engineering of functional nanomaterials with enhanced performance and versatility, contributing to material synthesis optimization for emerging applications. Materials science ; Sputtering ; Doping ; Modulation (music) ; Argon ; Optoelectronics ; Thin film ; Volumetric flow rate ; Nanotechnology ; Atomic physics ; Physics ; Mechanics ; Acoustics ZnO doping and properties ; Gas Sensing Nanomaterials and Sensors ; Perovskite Materials and Applications
Authors: Anandhu Krishnan | Sodiq O. Waheed | Sreerag Melayikandy | Ciara LaRouche | Meredith Paik | Christopher J. Schofield | Tatyana G. Karabencheva‐Christova
Source: ChemPhysChem (article, 2024-06-05)
Field: Chemistry — Inorganic Chemistry

Effects of Clinical Mutations in the Second Coordination Sphere and Remote Regions on the Catalytic Mechanism of Non‐Heme Fe(II)/2‐Oxoglutarate‐Dependent Aspartyl Hydroxylase AspH Aspartyl/asparaginyl hydroxylase (AspH) catalyzes the post-translational hydroxylations of vital human proteins, playing an essential role in maintaining their biological functions. Single-point mutations in the Second Coordination Sphere (SCS) and long-range (LR) residues of AspH have been linked to pathological conditions such as the ophthalmologic condition Traboulsi syndrome and chronic kidney disease (CKD). Although the clinical impacts of these mutations are established, there is a critical knowledge gap regarding their specific atomistic effects on the catalytic mechanism of AspH. In this study, we report integrated computational investigations on the potential mechanistic implications of four mutant forms of human AspH with clinical importance: R735W, R735Q, R688Q, and G434V. All the mutant forms exhibited altered binding interactions with the co-substrate 2-oxoglutarate (2OG) and the main substrate in the ferric-superoxo and ferryl complexes, which are critical for catalysis, compared to the wild-type (WT). Importantly, the mutations strongly influence the energetics of the frontier molecular orbitals (FMOs) and, thereby, the activation energies for the hydrogen atom transfer (HAT) step compared to the WT AspH. Insights from our study can contribute to enzyme engineering and the development of selective modulators for WT and mutants of AspH, ultimately aiding in treating cancers, Traboulsi syndrome and, CKD. Heme ; Chemistry ; Mechanism (biology) ; Catalysis ; Coordination sphere ; Stereochemistry ; Enzyme ; Mutation ; Biochemistry ; Crystallography ; Gene ; Crystal structure ; Physics Metal-Catalyzed Oxygenation Mechanisms ; Folate and B Vitamins Research ; Metabolism and Genetic Disorders