bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined application of DP4+ and ANN‐PRA to determine the relative configuration of natural products: The alpha‐bisabol case study
Authors: dos Santos Fernando Martins , da Silva Mota Gunar Vingre , Martorano Lucas Haidar , de Albuquerque Ana Carolina Ferreira , da Silva Claudinei Alves , da Silva Adalberto Manoel , de Jesus Chaves Neto Antônio Maia , Valverde Alessandra Leda , Cardoso Evani Ferreira , Costa Fabio Luiz Paranhos 
Published: March 2022

AbstractThe combination of computational methods and experimental data from Nuclear Magnetic Resonance (NMR) is a considerably valuable tool in the elucidation of new natural product structures and, also, in the structural revision of previously reported compounds. Until recently, only classical statistical parameters were used, for example, linear correlation coefficient (R2), mean absolute error (MAE), or root mean square deviation (RMSD), as a way to statistically “validate” the structure pointed out by experimental NMR spectra. Regarding the resolution of the relative configuration of organic molecules, novel tools were available in the last few years to assist in the NMR elucidation process. The most relevant are DP4+, which is based on a Bayesian probability, and ANN‐PRA, which is based on artificial neural networks. The combined application of these tools has become the most accurate and important alternative to solve structural and stereochemical problems in natural product chemistry. Therefore, herein, in this case study, we intended to promote these novel tools, exploring the strengths and limitations of each approach in resolving the relative configuration of the sesquiterpene alpha‐bisabol. We also highlighted the advantages of the complementary use of H‐ and C‐DP4+ to obtain optimal results in the differentiation of the stereoisomers, validating the proposal with ANN‐PRA method.
Chemiedidaktik: Vom Farbstoff zur Kopie
Authors: Ducci Matthias 
Published: March 2022

AbstractEnde des 19. Jahrhunderts entwickelten Forscher mit einem Thiazolfarbstoff ein Kopierverfahren, das als Diazotypie später wirtschaftlich erfolgreich wurde. Heute liefert das Verfahren Stoff für den Chemieunterricht. Schüler:innen können den Entdeckungsweg mit Experimenten nachvollziehen, lernen dabei eine photochemische Reaktion kennen und erzeugen selbst Kopien.
Accelerating Cell Migration along Radially Aligned Nanofibers through the Addition of Electrosprayed Nanoparticles in a Radial Density Gradient
Authors: Xue Jiajia , Wu Tong , Qiu Jichuan , Xia Younan 
Published: February 2022

AbstractScaffolds capable of promoting cell migration from the periphery toward the center along with the radial direction hold promises for tissue regeneration. Here a simple and general method is reported based on masked electrospray for the fabrication of such scaffolds by depositing collagen nanoparticles on radially aligned nanofibers in a radial density gradient. Placed between the metallic needle and the collector, an aperture with tunable opening sizes serves as the mask. By increasing the size of the opening at a fixed speed, the electrosprayed particles take a radial density gradient that decreases from the center to the periphery. When deposited on a glass slide, the radial density gradient of collagen nanoparticles promotes the migration of fibroblasts from the periphery toward the center. By replacing the glass slide with a scaffold comprised of radially aligned nanofibers, a synergetic effect arises to further accelerate cell migration along the radial direction. The synergistic effect can be attributed to a unique combination of the topographic cue arising from the aligned nanofibers and the haptotactic cue enabled by the graded nanoparticles. This study demonstrates a method to maximize cell migration from the periphery toward the center through a combination of topographic and haptotactic cues.
Linear Correlation Between Confined Explosive Quantity and Dent Volume of an Underlying Aluminium Block Using the SSRT Setup
Authors: Bauer Lukas , Benz Maximilian , Klapötke Thomas M. 
Published: February 2022

AbstractThe SSRT setup gives smart access to test various properties of explosive materials and requires only little substance quantities. Unlike the standardized SSRT, we studied the bulge development from the blast of different amounts of PETN (200–1300 mg). The bulge of the corresponding aluminum blocks was evaluated with the help of a profilometer (Keyence VR‐5200). This device, which measures the volume of the dents using the offset of structured light projected on the object, has allowed us to analyze the differences precisely. Despite the experimental limitations and the resulting undirected explosion direction, a throughout linear correlation between the respective amounts of PETN and the resulting dent depth could be determined. Our study thus forms an illustrative development of how the explosion behavior, represented by the dent of an aluminum block, of compressed energetic materials behaves in with increasing filling quantity, which is transferable to larger experimental setups as well as to other explosives.
Radiotherapy guidelines for rectal cancer in China (2020 Edition)
Authors: Liu Shixin , Jin Jing 
Published: March 2022

AbstractRectal cancer is one of the most common malignant tumors. In China, rectal cancer has been the third most frequently diagnosed cancer and the fifth leading cause of cancer death, with changes of residents’ lifestyle factors and diets. The best treatment for rectal cancer depends on many factors. Multidisciplinary Treatment has become the basis for improving the therapeutic effect, in which radiology is increasingly necessary for treating patients with rectal cancer. For patients who have extensive, fixed, bulky tumors or obvious nodal disease, radiotherapy and chemotherapy combined with surgery has emerged as the standard of care. For patients with metastatic disease, the reasonable combination of local and systemic therapy might be an alternative. Improvements in imaging, pathological diagnosis and radiation techniques provide a solid foundation for promoting the level of clinical practice in rectal cancer. High‐quality magnetic resonance imaging distinguishing risk stratification, molecular markers predicting therapeutic effect and prognosis, magnetic resonance imaging in delineating target volumes drawn, intensity‐modulated radiation therapy, and image‐guides radiation therapy for precision treatment delivery are all being widely applied in multiple centers. Furthermore, as the role of targeted therapy and immune therapy has become increasingly prominent, the attempt of combined radiotherapy is also ongoing. In view of the characteristics and current situation of diagnosis and treatment of rectal cancer in China, the guidelines will present the basis and reference for combined treatment and standardized treatments. Meanwhile, there may be continuous new advances in clinical practice, and that will be a new basis to update the guidelines, directly benefiting all rectal cancer patients and facilitating discipline developments.
The effects of geometrical flame feature on radiant heat flux prediction of horizontal jet flames using line source model
Authors: Ab Aziz Nur Shahidah , Md. Kasmani Rafiziana 
Published: February 2022

AbstractRadiant heat flux and impingement are the most common contributors to accident escalation involving jet fire. Thus, it is important to account for the radiant heat flux by using a semi‐empirical model as it is easy, cheaper, and could provide a reliable prediction. In this study, experimental observations were carried out for both free and impinging jet release. Propane was used as fuel and released from a circular nozzle with a diameter of 7.15 and 9.8 mm. The release velocity was fixed between 27 to 65 m/s, which is considered a subsonic release. In this work, two bases for radiant heat prediction using LSM were used: (i) horizontal kite shape approach and (ii) flame trajectory approach. It was observed that the prediction of radiant heat flux based on the flame trajectory for the free jet fire scenario gave the R2 value of 0.99, suggesting that the flame trajectory could give a better prediction as compared to the horizontal kite shape approach with R2 = 0.94. By using a similar assumption for impinging jet flames, it was observed that LSM based on flame trajectory could be used to predict the radiant heat flux with R2 = 0.99 for each case scenario.
Icarisid II rescues cognitive dysfunction via activation of Wnt/β‐catenin signaling pathway promoting hippocampal neurogenesis in APP/PS1 transgenic mice
Authors: Xiao Hong‐He , Chen Ji‐Cong , Li He , Li Rui‐Hai , Wang Hai‐Bo , Song Hui‐Peng , Li Hong‐Yan , Shan Guo‐Shun , Tian Yu , Zhao Yu‐Meng , Tian Jin‐Ming , Yang Jing‐Xian 
Published: March 2022

AbstractRestoring the compromised neurogenesis has been served as a potential strategy to rescue cognitive dysfunction of Alzheimer's disease (AD). In this study, we explored whether icarisid II (ICS II), a natural product possessing powerful neuroprotection, could recover the neurogenesis dysfunction of APP/PS1 mice, and investigated its underlying mechanisms. Our results showed that oral administration of ICS II could alleviate cognitive injuries of APP/PS1 mice, promote hippocampal neurogenesis, as well as stimulate Wnt/β‐catenin signal pathway confirmed by upregulated Wnt‐3a, phosphorylated glycogen synthase kinase‐3β (p‐GSK‐3β), and β‐catenin. ICS II also depressed mitochondrial fission evidenced by upregulated Mitofusin 1 (Mfn 1) and Mitofusin 2 (Mfn 2), and downregulated mitochondrial fission 1 protein (Fis 1), mitochondrial fission factor (Mff), and phosphorylated dynamin‐related protein 1 (p‐Drp 1). However, these effects of ICS II were blunted by XAV‐939, an inhibitor of Wnt/β‐catenin signaling pathway. In summary, our findings revealed that ICS II could improve neurogenesis and inhibit mitochondrial fission via activation of the Wnt/β‐catenin signaling pathway, which contributed to cognitive function restoration of APP/PS1 mice. This study discovered a novel mechanism involving neurogenesis regulation underlying the therapeutic effects of ICS II against AD.
Structure‐dependence in initial decomposition of trans‐1,2‐dimethylcyclohexyl isomers: Kinetic exploration and conformational analysis
Authors: Bian Huiting , Wang Yongjin , Li Jing , Zhao Jun 
Published: March 2022

AbstractTo elucidate the combustion behaviors of trans‐1,2‐dimethylcyclohexyl isomers, their initial decomposition have been explored by employing quantum chemical calculations coupled with transition state theory. All conformational structures and their interconversion mechanisms were studied. Originated from distinct conformers, all accessible transition states were explicitly identified in multiple paths for H‐transfer or β‐scission, and then were carefully used in kinetic predictions. The fairly speedy conformation fairly dominates over decomposition that allows thoroughly evaluating the contribution of various conformers to the final kinetics. Conformational analysis unravels that the most favorable 1,5 H‐transfer is only feasible for one twist‐boat with radical site in axial side chain accompanied by one isoclinal methyl group. The results for β‐scissions are affected by steric energies and substituent effects remained in conformational structures. These findings facilitate to finally figure out the proper kinetic parameters for each decomposition reaction for the implication in kinetic modeling simulation.
Modification and validation of the simultaneous detection of 38 pesticide residues method by ultra‐high‐performance liquid chromatography/tandem mass spectrometry with QuEChERS extraction in different oil crops and products
Authors: Lv Xi , Wang Fengzhong , Cui Ying , Fan Bei , Kong Zhiqiang , Yan Tingcai , Li Minmin 
Published: March 2022

RationaleOil crops and products are important food materials in daily life. Pesticide residues in food could directly and indirectly endanger human health. However, the method for detecting multiple pesticides simultaneously is limited. In this study, an easy and efficient method for the simultaneous determination of 38 pesticides in oil crops and products was established and validated.MethodsAll samples were treated with a modified QuEChERS procedure followed by ultra‐high‐performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) analysis. Mass spectrometry was performed in positive and negative ion electrospray ionization mode. The mobile phase consisted of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. The column used was a Poroshell 120 EC‐C18 and the flow rate was 0.3 mL/min.ResultsThe method was validated so that the calibration curves for all pesticides had good linearity in the concentration range of 10–1000 μg/L with correlation coefficients (R2) above 0.9945. The recovery rates were between 70.1 and 120.0%, with relative standard deviations (RSDs) (n = 6) ≤20.0%. The limits of quantification (LOQs) ranged from 0.5 to 10 μg/kg, limits of detection (LODs) ranged from 2.0 to 30 μg/kg, and the matrix effect (ME) ranged from −18.77 to 19.33%, respectively.ConclusionsThe method proved to be accurate, sensitive, and stable. It can be used for rapid screening and confirmation of 38 pesticide residues in oil crops and products which takes 10 min for sample extraction and clean‐up with less requirement of solvents. This study provides a technical basis for regulatory analysis and quality supervision of foods.
Comparative effectiveness of N95, surgical or medical, and non‐medical facemasks in protection against respiratory virus infection: A systematic review and network meta‐analysis
Authors: Kim Min Seo , Seong Dawon , Li Han , Chung Seo Kyoung , Park Youngjoo , Lee Minho , Lee Seung Won , Yon Dong Keon , Kim Jae Han , Lee Keum Hwa , Solmi Marco , Dragioti Elena , Koyanagi Ai , Jacob Louis , Kronbichler Andreas , Tizaoui Kalthoum , Cargnin Sarah , Terrazzino Salvatore , Hong Sung Hwi , Abou Ghayda Ramy , Radua Joaquim , Oh Hans , Kostev Karel , Ogino Shuji , Lee I‐Min , Giovannucci Edward , Barnett Yvonne , Butler Laurie , McDermott Daragh , Ilie Petre‐Cristian , Shin Jae Il , Smith Lee 
Published: February 2022

AbstractThe aim of this systematic review and network meta‐analysis is to evaluate the comparative effectiveness of N95, surgical/medical and non‐medical facemasks as personal protective equipment against respiratory virus infection. The study incorporated 35 published and unpublished randomized controlled trials and observational studies investigating specific mask effectiveness against influenza virus, SARS‐CoV, MERS‐CoV and SARS‐CoV‐2. We searched PubMed, Google Scholar and medRxiv databases for studies published up to 5 February 2021 (PROSPERO registration: CRD42020214729). The primary outcome of interest was the rate of respiratory viral infection. The quality of evidence was estimated using the GRADE approach. High compliance to mask‐wearing conferred a significantly better protection (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.23–0.82) than low compliance. N95 or equivalent masks were the most effective in providing protection against coronavirus infections (OR, 0.30; CI, 0.20–0.44) consistently across subgroup analyses of causative viruses and clinical settings. Evidence supporting the use of medical or surgical masks against influenza or coronavirus infections (SARS, MERS and COVID‐19) was weak. Our study confirmed that the use of facemasks provides protection against respiratory viral infections in general; however, the effectiveness may vary according to the type of facemask used. Our findings encourage the use of N95 respirators or their equivalents (e.g., P2) for best personal protection in healthcare settings until more evidence on surgical and medical masks is accrued. This study highlights a substantial lack of evidence on the comparative effectiveness of mask types in community settings.
How soil carbon fractions relate to soil properties and crop yields in dryland cropping systems?
Authors: Sainju Upendra M. , Liptzin Daniel , Stevens William B. 
Published: March 2022

AbstractSoil labile C fractions have been proposed as promising soil health indicators, but they have not been related to extensive soil properties and crop yields. We evaluated the relationships among soil organic carbon (SOC), labile C fractions, 62 soil physical, chemical, biological, and biochemical properties, and mean crop yields in two long‐term (14‐ and 36‐yr‐old) sites (Froid and Sidney, eastern Montana) under dryland farming. Soil C fractions were SOC, soil inorganic carbon (SIC), water‐extractable carbon (WEC), KMnO4–extractable carbon (POXC), potential carbon mineralization (PCM), and microbially active carbon (MAC). Treatments were conventional till and no‐till spring wheat (Triticum aestivum L.)/barley (Hordeum vulgaris L.), pea (Pisum sativum L.), and fallow rotations without N fertilization in Froid and with and without N fertilization in Sidney. Carbon fractions were greater in no‐till continuous cropping than till crop–fallow, with no effect of N fertilization at both sites. The principal component analysis showed that PCM was strongly associated with most soil physical, chemical, biological, and biochemical properties, followed by SOC, POXC, WEC, MAC, and SIC at both sites. More C fractions were related to soil properties in longer than shorter duration of the experiment. All C fractions, except SIC, were also related to mean crop yields across years. Although SOC was related to soil properties and crop yields, PCM may be used as a promising soil health indicator because of its greater sensitivity to management practices and better relationship to soil properties and crop yields than other labile C fractions.
Partially Reduced Graphene Oxide Membranes Crosslinked by an Anionic Porphyrin: Green Fabrication for High‐Performance Ion Sieving
Authors: Xu Xiao‐Ling , Mei Hongxin , Peng Aiping , Guo Yanjin , Ouyang Banlai , Liu Xiujuan , Li Ling , Chen Weihong 
Published: March 2022

AbstractGO membranes crosslinked by planar cation (e. g. TMPyP, a cationic porphyrin) meet the requirements of green fabrication, because TMPyP can pre‐assemble on GO sheets. However, their ion sieving performance are unsatisfactory. With shortened water channels, reduced graphene oxide (rGO) membranes owe high water flux, yet the retention of multivalent anions may goes down distinctly on account of Donnan effect decreasing obviously. Herein, we focus on the assembly between partially reduced graphene oxide (p‐rGO) and Anionic planar molecule (tetrasulfonic tetraphenyl porphyrin, TPPS), and then fabricate p‐rGO/TPPS composite membranes via assembling p‐rGO/TPPS sheets on base membrane. Anionic planar molecule is firstly used as crosslinking agent for graphene‐based membranes, which has the advantage of 100% atomic efficiency. The fabricated p‐rGO/TPPS membranes show better sieving performance than GO/TMPyP membranes on both side of rejection of Na2SO4 and water flux. Moreover, water flux go up to around another double though rejection decline slightly as the polyther sulfone (PES) base membrane with large surface pores is used.
Stability and Performance Enhancement of an Oligo (phenylene vinylene) Photocatalyst via Surface Grafting onto TiO2 for Visible‐Light Indigo Carmine Degradation
Authors: Acelas Mauricio , Castellanos Nelson J. , Sierra César A. 
Published: March 2022

AbstractThe chemical immobilization of a dibenzoic acid oligo (phenylene vinylene) (OPV) derivative for TiO2 sensitization was evaluated as a strategy to enhance both the stability and photocatalytic performance of this π‐conjugated moiety when applied to the photodegradation of indigo carmine dye (IC) as model pollutant. The results show that the electron injection from the photoexcited OPV to the TiO2 conduction band remarkably boosts the IC degradation ability under visible light illumination. The use of SiO2 as non‐photoactive support was also investigated to simultaneously determine the role of the inorganic support in the photocatalytic process. The spectroscopic, thermal, and surface characterization validated the successful grafting of the OPV to the inorganic supports. Moreover, superoxide radical and singlet oxygen were established as the active species involved in the dye degradation identifying an additional direct reducing pathway. Interestingly, the use of electron donors proved to be an ineffective approach to increase the system performance, entailing that the OPV regeneration proceeds chiefly via back electron transfer processes. Finally, the reusability tests confirmed that TiO2/OPV material retains up to 86 % of their photocatalytic activity during the first five cycles, demonstrating a critical enhancement in the organic conjugated framework stability.
Polysulfide Regulation by Hypervalent Iodine Compounds for Durable and Sustainable Lithium–Sulfur Battery
Authors: Wang Zhouhao , Hu Junping , Liu Jing , Lim Yew Von , Song Haobin , Wang Ye , He Tingting , Huang Chunlai , Yan Xinwen , Zhang Daohong , Huang Shaozhuan 
Published: February 2022

AbstractHerein, a type of hypervalent iodine compound—iodosobenzene (PhIO)—is proposed to regulate the LiPSs electrochemistry and enhance the performance of Li‐S battery. PhIO owns the practical advantages of low‐cost, commercial availability, environmental friendliness and chemical stability. The lone pair electrons of oxygen atoms in PhIO play a critical role in forming a strong Lewis acid–base interaction with terminal Li in LiPSs. Moreover, the commercial PhIO can be easily converted to nanoparticles (≈20 nm) and uniformly loaded on a carbon nanotube (CNT) scaffold, ensuring sufficient chemisorption for LiPSs. The integrated functional PhIO@CNT interlayer affords a LiPSs‐concentrated shield that not only strongly obstructs the LiPSs penetration but also significantly enhances the electrolyte wettability and Li+ conduction. The PhIO@CNT interlayer also serves as a “vice current collector” to accommodate various LiPSs and render smooth LiPSs transformation, which suppresses insulating Li2S2/Li2S layer formation and facilitates Li+ diffusion. The Li−S battery based on PhIO@CNT interlayer (6 wt% PhIO) exhibits stable cycling over 1000 cycles (0.033% capacity decay per cycle) and excellent rate performance (686.6 mAh g−1 at 3 C). This work demonstrates the great potential of PhIO in regulating LiPSs and provides a new avenue towards the low‐cost and sustainable application of Li−S batteries.
Correlating Symmetries of Low‐Frequency Vibrations and Self‐Trapped Excitons in Layered Perovskites for Light Emission with Different Colors
Authors: Lin Miao‐Ling , Dhanabalan Balaji , Biffi Giulia , Leng Yu‐Chen , Kutkan Seda , Arciniegas Milena P. , Tan Ping‐Heng , Krahne Roman 
Published: February 2022

AbstractThe soft hybrid organic–inorganic structure of two‐dimensional layered perovskites (2DLPs) enables broadband emission at room temperature from a single material, which makes 2DLPs promising sources for solid‐state white lighting, yet with low efficiency. The underlying photophysics involves self‐trapping of excitons favored by distortions of the inorganic lattice and coupling to phonons, where the mechanism is still under debate. 2DLPs with different organic moieties and emission ranging from self‐trapped exciton (STE)‐dominated white light to blue band‐edge photoluminescence are investigated. Detailed insights into the directional symmetries of phonon modes are gained using angle‐resolved polarized Raman spectroscopy and are correlated to the temperature‐dependence of the STE emission. It is demonstrated that weak STE bands at low‐temperature are linked to in‐plane phonons, and efficient room‐temperature STE emission to more complex coupling to several phonon modes with out‐of‐plane components. Thereby, a unique view is provided into the lattice deformations and recombination dynamics that are key to designing more efficient materials.