bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition Metal‐Free Diastereoselective Synthesis of β‐Carboline Tethered Dihydrofurocoumarin Derivatives
Authors: Banyal Naveen , Malakar Chandi C. , Kumar Rakesh , Singh Virender 
Published: February 2024

AbstractOne‐pot procedure has been developed for the synthesis of novel β‐carboline tethered trans 2,3‐furocoumarins via assembling 1‐formyl‐β‐carbolines, 4‐hydroxycoumarins, and phenacyl bromides in pyridine under transition metal‐free conditions. The strategy was also found applicable to gram scale synthesis and a library of 40 molecules has been developed. The significant features of this operationally facile approach includes high efficiency, short reaction time, excellent yields, multicomponent character of the reaction, metal‐free mild reaction conditions, and a column chromatography free purification procedure.
Nitrooxylative Dearomatization Reaction of β‐Naphthols with Hypervalent Iodine Reagent
Authors: Zhang Shan‐Shan , Li Muzi , Gu Qing , You Shu‐Li 
Published: February 2024

AbstractA catalyst‐free intermolecular dearomatization reaction of β‐naphthols with hypervalent‐iodine‐based nitrooxylating reagent is reported. Various nitrooxylated β‐naphthalenones bearing a quaternary carbon stereogenic center were obtained smoothly in good to excellent yields (up to 87 %) under mild conditions. This method features mild conditions, broad substrate scope and excellent chemoselectivity.
Supramolecular Modular Assembly of Imaging‐Trackable Enzymatic Nanomotors
Authors: Ye Zihan , Che Yanan , Dai Dihua , Jin Dongdong , Yang Yingwei , Yan Xiaohui , Ma Xing 
Published: February 2024

AbstractSelf‐propelled micro/nanomotors (MNMs) have shown great application potential in biomedicine, sensing, environmental remediation, etc. In the past decade, various strategies or technologies have been used to prepare and functionalize MNMs. However, the current preparation strategies of the MNMs were mainly following the pre‐designed methods based on specific tasks to introduce expected functional parts on the various micro/nanocarriers, which lacks a universal platform and common features, making it difficult to apply to different application scenarios. Here, we have developed a modular assembly strategy based on host–guest chemistry, which enables the on‐demand construction of imaging‐trackable nanomotors mounted with suitable driving and imaging modules using a universal assembly platform, according to different application scenarios. These assembled nanomotors exhibited enhanced diffusion behavior driven by enzymatic reactions. The loaded imaging functions were used to dynamically trace the swarm motion behavior of assembled nanomotors with corresponding fuel conditions both in vitro and in vivo. The modular assembly strategy endowed with host–guest interaction provides a universal approach to producing multifunctional MNMs in a facile and controllable manner, which paves the way for the future development of MNMs systems with programmable functions.
Functional Selection of Tau Oligomerization‐Inhibiting Aptamers
Authors: Wang Bang , Pan Xiaoshu , Teng I‐Ting , Li Xiaowei , Kobeissy Firas , Wu Zo‐Yu , Zhu Jiepei , Cai Guangzheng , Yan He , Yan Xin , Liang Mingwei , Yu Fahong , Lu Jianrong , Yang Zunyi , Biondi Elisa , Haskins William , Cao Y. Charles , Benner Steven A. , Tan Weihong , Wang Kevin K. 
Published: February 2024

AbstractPathological hyperphosphorylation and aggregation of microtubule‐associated Tau protein contribute to Alzheimer's Disease (AD) and other related tauopathies. Currently, no cure exists for Alzheimer's Disease. Aptamers offer significant potential as next‐generation therapeutics in biotechnology and the treatment of neurological disorders. Traditional aptamer selection methods for Tau protein focus on binding affinity rather than interference with pathological Tau. In this study, we developed a new selection strategy to enrich DNA aptamers that bind to surviving monomeric Tau protein under conditions that would typically promote Tau aggregation. Employing this approach, we identified a set of aptamer candidates. Notably, BW1c demonstrates a high binding affinity (Kd=6.6 nM) to Tau protein and effectively inhibits arachidonic acid (AA)‐induced Tau protein oligomerization and aggregation. Additionally, it inhibits GSK3β‐mediated Tau hyperphosphorylation in cell‐free systems and okadaic acid‐mediated Tau hyperphosphorylation in cellular milieu. Lastly, retro‐orbital injection of BW1c tau aptamer shows the ability to cross the blood brain barrier and gain access to neuronal cell body. Through further refinement and development, these Tau aptamers may pave the way for a first‐in‐class neurotherapeutic to mitigate tauopathy‐associated neurodegenerative disorders.
DNA interaction, biological, and structural identification studies of bivalent nano‐sized Nickel, Palladium, and Platinum chelates of 2‐(((Z)‐6‐chloro‐3‐((E)‐([2‐hydroxyphenyl]imino)methyl)‐4H‐chromen‐4‐ylidene)amino)phenol Schiff base ligand
Authors: Alaghaz Abdel‐Nasser M. A. , Alamier Waleed M. , Almashnowi Majed Y. 
Published: February 2024

New nano‐sized Ni(II), Pd(II), and Pt(II) Schiff base chelates of 2‐(((Z)‐6‐chloro‐3‐((E)‐([2‐hydroxyphenyl]imino)methyl)‐4H‐chromen‐4‐ylidene)amino)phenol were designed and manufactured. The structural characterization of these isolated compounds was accomplished through spectral measurements, thermal and elemental analyses, and magnetic moment and conductivity determinations. The nano‐sized metal(II) complexes molar conductance indicated that they exhibited non‐electrolytic behavior. The UV–Vis spectral data and magnetic moment provided evidence for producing octahedral geometries in the nano‐sized complexes of Ni(II), Pd(II), and Pt(II). Metal chelates' thermal characteristics and decomposition kinetics were examined through Coats‐Redfern technique. The kinetic aspects, including pre‐exponential factor (A), the entropy of activation (ΔS), and activation energy (E) were enumerated. The X‐ray diffraction (XRD) calculations results of the trivalent metal complexes showed that sharp and intense diffraction peaks signify their crystalline properties with nanoscale particle size, and another proof was obtained from the images of SEM, TEM, EDX, and AFM also homogeneous distribution over the complex surface was confirmed. Molecular modeling techniques were adopted to optimize the metal complexes geometry. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal(II) chelates. The acquired data revealed that the complexes exhibit a non‐intercalative or incomplete binding pattern when interacting with DNA. The calculated DNA‐complexes binding constants are 3.93 ± 0.02 × 10,4 1.67 ± 0.3 × 105 and 2.88 ± 0.03 × 105 M−1, for nano‐sized Ni(II), Pd(II) and Pt(II) Schiff base chelates, successively. Both Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive (Bacillus subtilis and Streptococcus pneumoniae) micro‐organisms were tested against H2L Schiff base ligand and its nano‐sized metal(II) complexes. Candida albicans and Aspergillus fumigatus were tested for antifungal activity, revealing that most complexes had activity lower than H2L ligand, while the complex of Ni(II) exhibited no discernible antifungal activities. Furthermore, the manufactured complexes underwent testing for their in‐vitro anticancer and antibacterial effectiveness. Furthermore, the complexes antioxidant activity was appraised through DPPH and ABTS inhibition tests, revealing distinct scavenging abilities on DPPH radicals. The complexes were ordered according to their scavenging capacity as follows: Ni(II) complex > Pd(II) complex > Pt(II) complex. Finally, the study of cell cycle arrest by the Ni(II), Pd(II), and Pt(II) complexes on HEPG2 has also been performed through flow cell cytometry.
A temperature‐responsive dual network hydrogel for reversible smart actuator
Authors: Xie Ting , Gao Yi , Li Zequan , Gao Wei 
Published: February 2024

AbstractNowadays, soft actuators have received extensive attention in many application fields, among which hydrogels have become an important choice for constructing soft actuators due to their unique properties. However, the actuating behaviors of hydrogel‐based actuators are usually monotonous due to their unchangeable shapes and structures. Herein, we report a temperature‐responsive hydrogel actuator with a bilayer structure. Based on the dual network structure (polyvinyl alcohol/poly acrylamide and polyvinyl alcohol/poly (N‐isopropylacrylamide), the actuators can realize the reinforcement compared with the single network. Because of the intrinsic lower critical solution temperature of poly (N‐isopropylacrylamide, both sides of actuators have different swelling rates, enabling them to achieve the thermal‐responsive actuation and shape programming. Therefore, this work is promising to provide a new strategy for designing temperature switches and thermally driven soft robots.
Frictional characteristics and vibration behavior of silicone rubber powders modified resin‐based friction materials
Authors: Gou Zhaoxi , Li Bo , Fei Jie , Fu Qiangang 
Published: February 2024

AbstractResin‐based friction materials (RFM) are widely used in vehicle brakes. However, the thermosetting resins and rigid fillers in RFM have low toughness and produce strong vibration behavior during continuous friction processes, which adversely affects the equipment. This work proposed a method for co‐blending modification of RFM with silicone rubber powders (SRP) to mitigate friction‐induced vibrations, and the mechanism of silicone rubber modification on the vibrational behavior of RFM during friction was investigated. The results demonstrate that SRP‐modified RFM exhibit excellent damping property and frictional characteristics. SRP modification improves the stability of the coefficient of friction and reduces fatigue wear. The wear rate of RFM modified with 10 wt% SRP reduced by 29% and the average amplitude of friction‐induced vibration decreased by 35.5% compared to unmodified RFM. This work provides both theoretical and practical foundations for designing and developing RFM with high damping, low wear, and low vibration characteristic.
Reactions of Heteroallenes with Salan‐based Ti(IV) Complexes: A Joint Experimental and Computational Study
Authors: Hipólito Joana , Meyrelles Ricardo , Maryasin Boris , Alves Luis G. , Martins Ana M. 
Published: February 2024

AbstractThe reaction of Ti(NMe2)4 with the salan ligand precursor H2N2O2H2 led to the formation of [(L*)Ti(NHMe2)2] (L*=N2O24−) that forms [(H2N2O2)TiCl2] upon reaction with two equiv. of Me3SiCl. [(L*)Ti(py)2] was obtained from the reaction of [Ti(NtBu)Cl2(py)3] with the sodium salt H2N2O2Na2. Treatment of [(L*)Ti(NHMe2)2] with two equiv. of tBuNCO led to the insertion of the isocyanate molecules into the Ti−Nsalan bonds with the formation of [{L*(N(tBu)CO)2}Ti]. Conversely, the reaction of [(H2N2O2)Ti(OiPr)2] with two equiv. of tBuNCO led to the insertion of one isocyanate molecule into a Ti−Nsalan bond with the formation of [{(HN2O2)(N(tBu)CO)}Ti(OiPr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan‐based Ti(IV) complexes.
Practical fixed‐time tracking control of quadrotor unmanned aerial vehicles with input saturation
Authors: He Zhansheng , Shen Jun , Zhang Zhipeng 
Published: February 2024

AbstractIn this article, an adaptive fixed‐time sliding mode control method is proposed for the quadrotor unmanned aerial vehicles (UAVs) with external disturbances and input saturation. Firstly, the fixed‐time sliding mode surface with a piecewise function enhances convergence speed and avoids singularity problems. The radial basis function neural networks (RBFNNs) are selected to estimate disturbances, and auxiliary systems are designed to address input saturation. Subsequently, an adaptive controller is created to ensure that the error system can converge into the neighborhood of origin within a fixed time. Furthermore, based on the proposed control approach, the stability of the closed‐loop system is analyzed with rigorous theoretical proof. Finally, comparative simulations are provided to illustrate the effectiveness and superiority of the proposed methodology.
In situ evaluation of the impact of metformin or verapamil coadministration with vildagliptin on its regional absorption from the rabbit’s intestine
Authors: Elmeniar Ahmed M. , Osman Mohamed A. , El‐Gizawy Sanaa A. , Modi Dimple , Charbe Nitin B. , El‐Kattan Ayman F. , El‐Tanani Mohamed , Haggag Yusuf A. , Tambuwala Murtaza M. 
Published: February 2024

AbstractThis research aims to identify regional differences in vildagliptin absorption across the intestinal membrane. Furthermore, it was to investigate the effect of verapamil or metformin on vildagliptin absorptive clearance. The study utilized an in situ rabbit intestinal perfusion technique to determine vildagliptin oral absorption from duodenum, jejunum, ileum, and ascending colon. This was conducted both with and without perfusion of metformin or verapamil. The findings revealed that the vildagliptin absorptive clearance per unit length varied by site and was in the order as follows: ileum < jejunum < duodenum < ascending colon, implying that P‐gp is significant in the reduction of vildagliptin absorption. Also, the arrangement cannot reverse intestinal P‐gp, but the observations suggest that P‐gp is significant in reducing vildagliptin absorption. Verapamil co‐perfusion significantly increased the vildagliptin absorptive clearance by 2.4 and 3.2 fold through the jejunum and ileum, respectively. Metformin co‐administration showed a non‐significant decrease in vildagliptin absorptive clearance through all tested segments. Vildagliptin absorption was site‐dependent and may be related to the intestinal P‐glycoprotein content. This may aid in understanding the important elements that influence vildagliptin absorption, besides drug–drug interactions that can occur in type 2 diabetic patients taking vildagliptin in conjunction with other drugs that can modify the P‐glycoprotein level.
Vitamin D metabolism is altered during aging alone or combined with obesity in male mice
Authors: Bournot Lorrine , Payet Thomas , Marcotorchino Julie , Awada Manar , Rouquet Thaïs , Breniere Thomas , Couturier Charlène , Astier Julien , Halimi Charlotte , Reboul Emmanuelle , Sicard Flavie , Mounien Lourdes , Roux Julien , Bariohay Bruno , Landrier Jean François 
Published: February 2024

AbstractAging and obesity are associated with a decrease in plasma 25‐hydroxyvitamin D (25(OH)D) levels. In the context of a growing aging population and the rising incidence of obesity, we hypothesized that aging process, either independently or in combination with obesity, could influence vitamin D (VD) metabolism, consequently resulting in the reduced 25(OH)D plasma concentrations. C57BL/6JRJ young (6 months) and old (23 months) mice fed with control (CD) or high fat diet (HF) were compared. Plasma and adipose concentration of cholecalciferol and 25(OH)D and mRNA expression of genes coding for the main VD actors were analyzed. Aging was associated with a decrease in plasma 25(OH)D levels, whereas combined effect of obesity and aging did not generate a cumulative effect on plasma 25(OH)D levels. The mRNA expression of Cyp27a1, Cyp3a11, and Cyp2j6 were decreased in the liver during aging. Together, these regulations could explain the reduced 25‐hydroxylation. Interestingly, the lack of cumulative reduction of 25(OH)D in aged and obese mice could be related to the strong induction of Cyp2j6. In kidneys, a complex modulation of Cyp27b1 and Cyp24a1 could contribute to the reduced 25‐hydroxylation in the liver. In white adipose tissue, an induction of Cyp2r1 was observed during aging and obesity, together with an increase of 25(OH)D quantity, suggesting an exacerbated storage that may participated to the reduced plasma 25(OH)D levels. These findings support the notion that aging alone or combined with obesity, induces regulation of VD metabolism in the organs, beyond the classical reduction of epidermal VD precursor, which may contribute to the decrease in 25(OH)D levels.
A large‐scale production of mesenchymal stem cells and their exosomes for an efficient treatment against lung inflammation
Authors: Zhang Jinsong , Lin Ruyi , Li Yingyu , Wang Jiawen , Ding Huiqing , Fang Panfeng , Huang Yingzhi , Shi Jing , Gao Jianqing , Zhang Tianyuan 
Published: February 2024

AbstractMesenchymal stem cells (MSCs) and their produced exosomes have demonstrated inherent capabilities of inflammation‐guided targeting and inflammatory modulation, inspiring their potential applications as biologic agents for inflammatory treatments. However, the clinical applications of stem cell therapies are currently restricted by several challenges, and one of them is the mass production of stem cells to satisfy the therapeutic demands in the clinical bench. Herein, a production of human amnion‐derived MSCs (hMSCs) at a scale of over 1 × 109 cells per batch was reported using a three‐dimensional (3D) culture technology based on microcarriers coupled with a spinner bioreactor system. The present study revealed that this large‐scale production technology improved the inflammation‐guided migration and the inflammatory suppression of hMSCs, without altering their major properties as stem cells. Moreover, these large‐scale produced hMSCs showed an efficient treatment against the lipopolysaccharide (LPS)‐induced lung inflammation in mice models. Notably, exosomes collected from these large‐scale produced hMSCs were observed to inherit the efficient inflammatory suppression capability of hMSCs. The present study showed that 3D culture technology using microcarriers coupled with a spinner bioreactor system can be a promising strategy for the large‐scale expansion of hMSCs with improved anti‐inflammation capability, as well as their secreted exosomes.
The immune system of prokaryotes: potential applications and implications for gene editing
Authors: Liu Siyang , Liu Hongling , Wang Xue , Shi Lei 
Published: February 2024

AbstractGene therapy has revolutionized the treatment of genetic diseases. Spearheading this revolution are sophisticated genome editing methods such as TALENs, ZFNs, and CRISPR‐Cas, which trace their origins back to prokaryotic immune systems. Prokaryotes have developed various antiviral defense systems to combat viral attacks and the invasion of genetic elements. The comprehension of these defense mechanisms has paved the way for the development of indispensable tools in molecular biology. Among them, restriction endonuclease originates from the innate immune system of bacteria. The CRISPR‐Cas system, a widely applied genome editing technology, is derived from the prokaryotic adaptive immune system. Single‐base editing is a precise editing tool based on CRISPR‐Cas system that involves deamination of target base. It is worth noting that prokaryotes possess deamination enzymes as part of their defense arsenal over foreign genetic material. Furthermore, prokaryotic Argonauts (pAgo) proteins, also function in anti‐phage defense, play an important role in complementing the CRISPR‐Cas system by addressing certain limitations it may have. Recent studies have also shed light on the significance of Retron, a reverse transcription transposon previously showed potential in genome editing, has also come to light in the realm of prokaryotic immunity. These noteworthy findings highlight the importance of studying prokaryotic immune system for advancing genome editing techniques. Here, both the origin of prokaryotic immunity underlying aforementioned genome editing tools, and potential applications of deaminase, pAgo protein and reverse transcriptase in genome editing among prokaryotes were introduced, thus emphasizing the fundamental mechanism and significance of prokaryotic immunity.
Effect of extracellular matrices on production and potency of mesenchymal stem cell‐derived exosomes
Authors: Somadder Rittika , Faraj Lina , Datta Saurav , Kanapathipillai Mathumai , Ghosh Gargi 
Published: February 2024

AbstractMesenchymal stem cell (MSC) derived exosomes have emerged as potential acellular therapeutics for various tissue regenerative applications. However, successful clinical translation of exosome‐based therapy is limited by lack of a structured production platform. Thus, in this study, the effect of decellularized extracellular matrix (dECM) was assessed on the production and potency of exosomes secreted by bone marrow‐derived human MSCs. The results indicate that there was a ∼2‐fold increase in MSC‐exosome production when MSCs were cultured on dECM compared to TCP. Further, our study revealed that dECM generation induced by ascorbic acid (AA) up to 100 µg mL−1 highly increased exosome yield thereby indicating a potential scale up method for MSC exosome production. The bioactivity of exosomes was investigated by their ability to improve the healing of wounded human skin explants. Wound closure was enhanced in the presence of exosomes isolated from MSCs cultured on ascorbic acid‐induced dECM compared to TCP generated MSC‐exosomes. In summary, this study suggests a promising solution to a major bottleneck in large‐scale production of MSC exosomes for cell‐free therapy.
Tracing endogenous proteins in living cells through electrotransfer of mRNA encoding chromobodies
Authors: Juncker Théo , Richert Ludovic , Masson Murielle , Zuber Guy , Chatton Bruno , Donzeau Mariel 
Published: February 2024

AbstractChromobodies made of nanobodies fused to fluorescent proteins are powerful tools for targeting and tracing intracellular proteins in living cells. Typically, this is achieved by transfecting plasmids encoding the chromobodies. However, an excess of unbound chromobody relative to the endogenous antigen can result in high background fluorescence in live cell imaging. Here, we overcome this problem by using mRNA encoding chromobodies. Our approach allows one to precisely control the amount of chromobody expressed inside the cell by adjusting the amount of transfected mRNA. To challenge our method, we evaluate three chromobodies targeting intracellular proteins of different abundance and cellular localization, namely lamin A/C, Dnmt1 and actin. We demonstrate that the expression of chromobodies in living cells by transfection of tuned amounts of the corresponding mRNAs allows the accurate tracking of their cellular targets by time‐lapse fluorescence microscopy.
Improvement of an enzymatic cascade synthesis of nicotinamide mononucleotide via protein engineering and reaction‐process reinforcement
Authors: Peng Feng , Hong Jian , Cui Jie , An Ya‐Ni , Guo Qian , Shen Qi , Cheng Feng , Xue Ya‐Ping , Zheng Yu‐Guo 
Published: February 2024

AbstractEnzymatic synthesis of β‐nicotinamide mononucleotide (NMN) from D‐ribose has garnered widespread attention due to its cheap material, the use of mild reaction conditions, and the ability to produce highly pure products with the desired optical properties. However, the overall NMN yield of this method is impeded by the low activity of rate‐limiting enzymes. The ribose‐phosphate diphosphokinase (PRS) and nicotinamide phosphoribosyltransferase (NAMPT), that control the rate of the reaction, were engineered to improve the reaction efficacy. The actives of mutants PRS‐H150Q and NAMPT‐Y15S were 334% and 57% higher than that of their corresponding wild‐type enzymes, respectively. Furthermore, by adding pyrophosphatase, the byproduct pyrophosphate which can inhibit the activity of NAMPT was degraded, leading to a 6.72% increase in NMN yield. Following with reaction‐process reinforcement, a high yield of 8.10 g L−1 NMN was obtained after 3 h of reaction, which was 56.86‐fold higher than that of the stepwise reaction synthesis (0.14 g L−1), indicating that the in vitro enzymatic synthesis of NMN from D‐ribose and niacinamide is an economical and feasible route.