bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of pterostilbene in Escherichia coli from resveratrol on macroporous adsorption resin using a two‐step substrate addition strategy
Authors: Yingling Bao , Xueqin Wu , Xiaolong Chen 
Published: October 2024

AbstractPterostilbene (PST), a 3’,5’‐O‐methylated derivative of resveratrol (RSV), is a potent natural antioxidant produced by some plants in trace amounts as defense compound. It exhibits various health‐promoting activities, such as anticancer, antiviral, and antimicrobial effects. Large‐scale biosynthesis of PST is crucial due to the challenges associated with extracting it from plants. This study aims to develop an efficient method for PST production using an engineered Escherichia coli strain by feeding RSV as a precursor. We introduced a two‐step substrate addition strategy combined with immobilized RSV (IMRSV) on macroporous adsorption resin (MAR) to enhance PST production. Five MARs were selected for RSV immobilization, and the substrate addition strategy and fermentation parameters for PST synthesis were optimized. A maximum PST concentration of 403 ± 9 mg/L was achieved, representing a 239% increase over the control, which in a one‐step addition of free RSV. The PST titer reached 395 ± 24 mg/L in a 3‐L bioreactor. In conclusion, the combination of a two‐step substrate addition system and IMRSV is a promising approach for the economical and industrial‐scale production of PST.
Hydrosilylation of Alkynes Catalyzed by an Iron(II) PCP Pincer Alkyl Complex
Authors: Schratzberger Heiko , Kirchner Karl 
Published: October 2024

AbstractVinylsilanes are very useful building blocks in organic synthesis and have widespread applications in life sciences and materials chemistry. Here we describe the potential of complex cis‐[Fe(PCP‐iPr)(CH2CH2CH3)(CO)2] as an effective catalyst for the hydrosilylation of both terminal and internal alkynes with SiPhH3 to give vinylsilanes. The reactions were typically performed with a catalyst loading of 1 mol% for 24 h at 70 °C. The catalytic reaction is initiated by migratory insertion of a CO ligand into the Fe─alkyl bond to yield an acyl intermediate, which reacts with silanes to form the 16e− Fe(II) silyl catalyst [Fe(PCP‐iPr)(SiPhH2)(CO)]. In the case of aliphatic terminal alkynes good regioselectivity (anti‐Markovnikov addition) toward the thermodynamically more stable β‐(E)‐vinylsilanes in ratios of up to 10:90 was achieved, while for aromatic alkynes the selectivities were poor with ratios of β‐(Z)‐ to β‐(E)‐vinylsilanes of about 40:60. With internal unsymmetrical alkynes, the two possible regioisomers of the syn‐addition of SiPhH3 were obtained in different ratios with no clear trend toward one regioisomer. Internal symmetrical alkynes yielded exclusively the respective syn‐products in high yields. Mechanistic investigations including deuterium labelling studies were undertaken to provide a reasonable reaction mechanism.
Red Mud as a Potential Catalyst for Petrochemicals Production From Oxygenated Aromatic Plastic Wastes via Fast Pyrolysis
Authors: Pal Subhan Kumar , Prabhudesai Vallabh S. , Mohanty Kaustubha , Vinu Ravikrishnan 
Published: October 2024

AbstractThe increased rate of postuse accumulation of the heteroatom‐containing plastic wastes, like polyethylene terephthalate (PET), polycarbonate (PC) and polyurethane (PU), in the environment propels the research for effective and sustainable valorization. In this study, PET from bottle waste, PC from compact discs, and PU from waste wind turbine blade were characterized and employed for fast pyrolysis experiments. Importantly, red mud (RM), a mixed oxide rich in Fe, Al, Si, Na, and Ca, was used as a catalyst for fast pyrolysis. The effects of temperature and feed/catalyst ratio on product yields were studied to elucidate the product formation mechanism. Benzoic acid and its derivatives, bisphenol‐A and oxygenated aromatics, and 4,4′‐methylenebisbenzamine were the major products obtained from the noncatalytic fast pyrolysis of PET, PC, and PU, respectively. The use of RM improved the yield of aromatic hydrocarbons from PET to 27.8 wt% at 550 °C, phenolics from PC to 46.6 wt% at 550 °C, and 4,4′‐methylenebisbenzamine to 34.9 wt% at 650 °C. The catalytic activity of RM is ascribed to the presence of active basic sites. The present study paves the path for the catalytic upcycling of challenging plastic wastes using industrial waste, like RM, as a sustainable catalyst from a circular economy viewpoint.
Model Catalytic Studies on the Thermal Dehydrogenation of the Benzaldehyde/Cyclohexylmethanol LOHC System on Pt(111)
Authors: Schwaab Valentin , Hemauer Felix , Steffen Julien , Waleska‐Wellnhofer Natalie J. , Marie Freiberger Eva , Steinmetz Marius , Görling Andreas , Wasserscheid Peter , Steinrück Hans‐Peter , Papp Christian 
Published: October 2024

AbstractWe investigated the dehydrogenation reaction and the thermal robustness of the liquid organic hydrogen carrier (LOHC) couple benzaldehyde/cyclohexylmethanol on a Pt(111) model catalyst in situ in synchrotron radiation photoelectron spectroscopy‐ and complementary temperature‐programmed desorption experiments. The system stores hydrogen in a cyclohexyl group and a primary alcohol functionality and achieves an attractive hydrogen storage capacity of 7.0 mass %. We observed a stepwise dehydrogenation mechanism, characterized by a low temperature dehydrogenation of the alcohol group at 235 K. However, stability limitations challenge the system's application as reversible hydrogen storage solution, as the resultant aldehyde was found to decompose during the dehydrogenation of its cyclohexyl group (between 250 and 350 K). A comparison of cyclohexylmethanol with the structurally related secondary alcohol (1‐cyclohexylethanol; 6.3 mass % hydrogen) revealed a parallel stepwise dehydrogenation pattern for both compounds, but a technically relevant superior thermal robustness of the latter, demonstrating the influence of the alcohol‐group's substitution degree on the dehydrogenation characteristics of alcohol‐functionalized LOHCs. Density functional theory calculations are in agreement with the experimentally observed stability trend.
Formal Transformation of Benzylic Carboxylic Acids to Phenols
Authors: Lou Chenhao , Huang Qiuwei , Lv Leiyang , Li Zhiping 
Published: October 2024

AbstractPhenols play a crucial role as core structural motifs in natural products and also serve as fundamental building blocks in synthetic chemistry. Apart from the known protocols for the conversion of aryl precursors to phenols (i. e., decarboxylative oxygenation), we report here the efficient synthesis of phenols from the stable and readily available benzylic carboxylic acids under mild reaction conditions. The photocatalytic conversion of carboxylic acids to peroxides is a crucial step in this strategy, allowing the subsequent C−O bond formation via Hock rearrangement.
Comparison of Positioning Error Prediction Results of Industrial Robots Based on Three Different Types of Neural Networks
Authors: Wang Xin 
Published: October 2024

ABSTRACTWith the increasing development of industry, the market demand for manufacturing has shifted to large‐scale customized production. This poses new challenges to the production flexibility of industrial robots. The offline programming method can perfectly meet this challenge. But its disadvantage is that it relies heavily on the absolute positioning accuracy of industrial robots. In recent years, there has been an increasing number of studies using neural networks (NN) to predict the positioning errors of industrial robots to improve their absolute positioning accuracy. However, most of these studies only focus on the application of NNs, and do not compare the prediction results and performance of different kinds of NNs. This paper selects three typical network models: backpropagation neural network (BPNN), particle swarm algorithm optimization BPNN (PSO‐BPNN), and radial basis function neural network (RBFNN). Through in‐depth experiments and analysis of these networks, the purpose is to reveal their respective prediction effects and characteristics and to summarize their advantages and disadvantages. Experimental results show that BPNN performs poorly in predicting positioning errors. As an optimization method, the particle swarm algorithm can effectively improve the prediction performance of BPNN. In contrast, the RBFNN performs well, which makes it very suitable for predicting the positioning error of industrial robots.
An Ultra‐Short‐Term Wind Power Prediction Method Based on Spatiotemporal Characteristics Fusion
Authors: Pi Yuzhen , Yuan Quande , Zhang Zhenming , Wen Jingya , Kou Lei 
Published: October 2024

ABSTRACTAiming at the problem that the existing ultra‐short‐term wind power prediction methods lack consideration of the spatial correlation characteristics of wind farms, resulting in insufficient prediction accuracy, an ultra‐short‐term wind power prediction method based on spatiotemporal characteristics fusion is proposed in this article. First, the fluctuation difference of the time window of wind power is input into the K‐means clustering algorithm to cluster wind farms into several clusters based on power fluctuation similarity. Then, the principal component analysis algorithm is used to reduce the dimensionality of numerical weather prediction data combinations in different regions to reduce the impact of redundant information on modeling accuracy. Finally, a convolutional long‐short‐term memory neural network is designed to extract spatiotemporal features of wind power data and output prediction results. The experimental verification on 18 wind farms in a province in China shows that the proposed wind power prediction method has an average root mean square error of only 0.1257 and has certain applicability.
Association of Periodontal Condition With Impaired Glucose Tolerance: Results of a 15‐Year Follow‐Up Study
Authors: Myllymäki Ville , Ylöstalo Pekka , Suominen Anna Liisa , Knuuttila Matti , Rajala Ulla , Keinänen‐Kiukaanniemi Sirkka , Anttila Sirpa , Saxlin Tuomas 
Published: October 2024

ABSTRACTObjectivesThe aim of this study was to investigate whether periodontal condition is associated with the development of impaired glucose tolerance (IGT).Material and MethodsThis study was based on a subpopulation of a cohort of persons born in 1935 and living in Oulu, Finland, on October 1, 1990. The participants were normoglycemic (no previously diagnosed diabetes mellitus and a 2‐h oral glucose tolerance test [OGTT] blood glucose < 7.8 mmol/L) in the baseline examinations (1990–1992) and had fasting blood glucose < 7.0 mmol/L in the follow‐up examinations (2007–2008) (n = 225). The outcome was IGT on follow‐up, measured by a blood glucose level of ≥ 7.8 mmol/L after OGTT. The exposure was the periodontal condition at baseline categorized into four groups: 0, 1–6, ≥ 7 sites with deepened (≥ 4 mm) periodontal pockets, and edentulousness.ResultsA total of 23% of the participants developed IGT. The adjusted incidence rate ratios with 95% confidence intervals (CI) for dentate participants with 1–6 sites and ≥ 7 sites with deepened periodontal pockets, and edentate participants (reference category dentate participants without deepened periodontal pockets) were 1.5 (95% CI, 0.6–4.0), 1.8 (95% CI, 0.7–4.4), and 1.6 (95% CI, 0.6–4.0), respectively.ConclusionsPoor periodontal condition may predispose individuals to IGT; however, further studies on this matter are warranted.
Periodontal Evaluation for a New Alkasite Restorative Material in Noncarious Cervical Lesions: A Randomized‐Controlled Clinical Trial
Authors: Mustafa Khattab , Alfakhry Ghaith , Milly Hussam 
Published: October 2024

ABSTRACTObjectivesThis study aims to evaluate the periodontal condition adjacent to Cention N (CN) restorations applied for noncarious cervical lesions (NCCL) compared with resin‐modified glass ionomer cement (RM‐GIC) restorations in terms of plaque accumulation, attachment loss, and gingival inflammation.Materials and MethodsThis is a double‐blind split‐mouth three‐armed randomized‐controlled clinical trial. The study arms are RM‐GIC (FUJI II LC), CN + adhesive system, and CN + retentive groove. The study included 25 restorations per arm. Follow‐ups were performed at 1 week, 3, 6, and 9 months after the application of the restorations. The periodontal condition was evaluated using the plaque index (PI), the bleeding on probing index (BOP), and the probing depth (PD). Appropriate tests were used to perform statistical analyses (α = 0.05).ResultsThere was no significant difference between Cention N and RM‐GIC regarding the studied variables. However, after the application of the restorations, it was noted that the PI and the PD mean values increased. The average increase after 9 months was 0.06 and 0.34 for PI and PD, respectively, with that of PD being significant. It was also noted that the percentage of positive BOP sites increased at the 1‐week follow‐up for all study groups and afterward dropped to near preintervention values at the 3‐month and later follow‐ups.ConclusionsThe two ion‐releasing materials Cention N and RM‐GIC have a comparable and clinically acceptable effect on the gingival tissue when restoring NCCLs. The combined effect of the gingival retraction cord and the rubber dam clamp on the periodontal tissues might be more important to consider, especially in relation to the probing depth. Future long‐term studies are needed to evaluate the effect of Cention N on the subgingival biofilm in comparison with nonion‐releasing restorative materials, and subsequently, its effect on gingival inflammation.Clinical Trial RegistrationThis clinical trial was registered in clinicaltrial.gov clinical registry under protocol #NCT05593159.
Anomalous Catalytic Performance on Non‐Active‐Site Carbon Substrate
Authors: Sun Wenxing , Hu Yao , Gong Jiaxuan , Zhang Li , Li Zhi , Fu Qiang , Lan Haihui , Wang Donghui , Yan Mo , Xia Huicong , Du Mingliang 
Published: October 2024

AbstractCarbon‐based nanomaterials are gaining attention in electrocatalysis. This study investigates the inherent nitrate reduction activity (NO3RR) of commercial carbon paper as a substrate. Results showed that carbon paper, without additional catalysts, achieved approximately 80.42 % ammonia (NH3) Faradaic efficiency (FE) at −2.1 V vs. Hg/HgO in alkaline conditions, 83.51 % NH3 FE at −1.9 V vs. Ag/AgCl in neutral conditions, and 14.53 % NH3 FE at −1.9 V vs. MSE in acidic conditions. Density Functional Theory (DFT) calculations revealed energy barriers of 2.66 eV, 0.95 eV, and 1.37 eV, respectively. Molecular physisorption on the carbon paper surface generates an induced electric field, promoting charge transfer between the carbon paper and the adsorbed molecules, thus enhancing the activity of the carbon paper. These findings highlight the importance of considering the intrinsic catalytic properties of carbon substrates in catalyst design and evaluation, as overlooking these properties can lead to inaccurate performance assessments. This study emphasizes the need for a comprehensive approach to optimize catalytic systems.
New Insights Into the Population Structure of Hector's Dolphin (Cephalorhynchus hectori) Revealed Using Environmental DNA
Authors: Bennington S. M. , Bourke S. D. , Wilkinson S. P. , Englebert N. , Bond D. M. , Jeunen G.‐J. , Dawson S. , Slooten E. , Dillingham P. W. , Rayment W. J. , Alexander A. 
Published: October 2024

ABSTRACTEnvironmental DNA (eDNA) is frequently used for detecting species and describing biodiversity through metabarcoding techniques. More recently, there has been emerging evidence that eDNA can be used to investigate intraspecific variability, providing novel pathways to explore population genetics questions. However, it can be difficult to distinguish between true intraspecific variation and PCR/sequence error, and the presence of DNA from multiple individuals makes using traditional frequency‐based approaches challenging. Here, we explore how eDNA can be used to investigate population structure of Hector's dolphin (Cephalorhynchus hectori), an endemic, endangered, and culturally important (taonga) species. In doing so, we present a simple and effective method to filter out noise due to PCR/sequence error and show how treating haplotype detections equally can provide similar results to frequency‐based approaches from traditional sampling methods. Over the 2022/23 Austral summer, we collected 85 water samples close to Hector's dolphins, and three negative controls, across three areas on the east coast of Aotearoa New Zealand's South Island: Banks Peninsula (n = 41), Timaru (n = 33), and Dunedin (n = 14). We targeted a 348 bp region of the cetacean D‐loop in the mitochondrial DNA (mtDNA) and obtained positive detections in 68 (77%) water samples, confidently identifying seven haplotypes across the study area. The occurrence of specific haplotypes and the overall frequencies in Banks Peninsula and Timaru matched well with previous tissue‐based studies and were similar to other East Coast South Island (ECSI) subpopulations. In Dunedin, however, our results indicate a closer relationship to South Coast populations, suggesting that the membership within the ECSI population be reconsidered, which has implications for how this subpopulation is managed. We show that eDNA sampling can be used to elucidate matrilineal population structure for Hector's dolphin and provide a simple method that could be applied to other eDNA‐based studies of any taxa.
Regioselective Intermolecular Hydroamidation of β‐CF3‐1,3‐Enynamides: An Approach to Tri‐Substituted γ‐CF3‐Allenamides
Authors: Cao Yuxuan , Yu Zongxiang , Chen Yizhen , Liu Lu , Xiao Yuanjing 
Published: October 2024

AbstractA simple base mediated, highly regioselective 1,4‐hydroamidation of β‐CF3‐1,3‐enynamides with secondary amides for synthesis of tri‐substituted γ‐CF3‐allenamides compounds was developed. N‐alkyl sulfonamides are generally good candidates for the present transformation. γ‐CF3‐allenamides could be employed for synthesis of potential value‐added compounds such as fluorinated halogenated pyrrole, tetrahydroquinoline and 2‐CF3‐putrescine derivatives.
Cu‐Catalyzed Coupling of Sulfonyl Chlorides with Alkenes: Synthesis of Dienyl Sulfones and β‐Chlorosulfones
Authors: Choudhary Priyanka , Ranjan Ravikant S. , Fernandes Rodney A. 
Published: October 2024

AbstractThis work reports a Cu‐catalyzed coupling technique for synthesizing (E)‐dienyl sulfones and β‐chlorosulfones from 1‐arylbutadienes and styrenes, respectively. By employing easily available and inexpensive reagents, this method enables the synthesis of a diverse array of dienyl sulfones and β‐chlorosulfones with excellent functional group tolerance under base‐ and oxidant‐free conditions. It also proves versatile for the late‐stage functionalization of drug molecules and the scale‐up reactions. The method showcases notable selectivity, gentle reaction conditions, and compatibility with various functional groups as demonstrated through 66 examples with excellent display of regioselectivity.
Factorial design methodology for synthesizing zeolites: A critical review
Authors: García‐Estrada R. , Hernández‐Palomares A. , Reyes‐Vidal Yolanda , Robles Irma , Espejel‐Ayala F. 
Published: October 2024

AbstractThis review shows an outlook about several works which have used the factorial design methodology for synthesizing zeolites and mesoporous materials, included the use of wastes as sources of silicon and aluminum. In the bibliography several interesting works were identified with a complete development of the factorial design methodology. However, there are other works that showed a limited statistical analysis of the results. In spite of these issues, their contribution in the advance of synthesis of zeolites is important. Moreover, different ways to measure the crystallinity were detected being the X‐ray diffraction (XRD) the most used technique. This work also gives a proposal of the complete factorial design methodology as a guide in future works for synthesizing zeolites or zeo‐types materials. This work presents a detailed review of the methodology of designing experiments for the synthesis of zeolite or zeo‐type materials, where it has been shown and analyzed the type of design used, because the choice of a design involves a large number of experiments or few experiments thus facilitating the production of zeolite, in addition to the factors that influence the synthesis give information of the type to obtained zeolites, also includes a guide for applying this methodology. Experiment design methodology can help to produce high quality zeolites from virgin raw material or waste that impact the economy of the zeolite industry.
Mechanism and application of drill pipe bending induced borehole collapse in soft coal seam drilling
Authors: Yonglong Wang , Zaijiang Yu , Jiakuan Guo , Kang Du , Denghui Ma , Aoqi Zhao 
Published: October 2024

AbstractGas extraction drilling is a necessary measure for managing gas hazards. For soft coal seams where gas extraction drilling holes are prone to collapse, it is believed that drill rod disturbance is the main cause of hole collapse. This study proposes a research approach to reduce wall stress by optimizing the drill rod structure. Through theoretical analysis, numerical simulation, and industrial tests, a stress model for the drill rod inside the hole was established, and a wall stress equation was derived. The effects of various parameters on wall stress were analyzed. The study suggests optimizing the drill rod structure to reduce the disturbance‐induced wall stress. SolidWorks was used for drilling stress simulation, and a four‐winged concave groove drill rod was developed. After strength verification, comparative industrial tests were conducted. The research results show that as the line density increases, the wall stress of the drilling hole increases. As the length of the suspended section increases, the wall stress initially decreases and then increases. With increasing drilling thrust, wall stress increases linearly, and the growth rate is greater with a larger diameter difference between the drill hole and the drill rod. Numerical simulation results indicate that the critical point maximum stress at the hole entrance, the critical point maximum stress at the hole bottom, and the average stress at the bottom section of the four‐winged concave groove drill rod with a concavity of 5 are significantly reduced compared to those of circular and grooved drill rods. Industrial test results show that using the four‐winged concave groove drill rod significantly reduces the extent of hole collapse. This study provides a reference for addressing the issue of hole collapse in gas extraction drilling for soft coal seams.