bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Tetrahydropyridazines via Pd‐Catalyzed Carboamination of Alkenyl Hydrazones
Authors: Guo Yajing , Zhao Jinbo , Zhang Qian
Published: January 2020

We report herein a facile approach to tetrahydropyridazines, a scaffold found in many natural products and biologically active entities, via Pd‐catalyzed carboamination of readily available alkenyl hydrazones with aryl and alkenyl halides. Preliminary studies showed its promise for enantioselective synthesis. This work offers an expedient access to the tetrahydropyridazine scaffold bearing substitution patterns, thus significantly increasing the availability of these derivatives for downstream evaluation.

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Continuous Flow Preparation of Enantiomerically Pure BINOL(s) by Acylative Kinetic Resolution
Authors: Lai Junshan , Neyyappadath Rifahath M. , Smith Andrew D. , Pericàs Miquel A.
Published: January 2020

A polystyrene‐immobilized isothiourea has been applied to the enantioselective acylative kinetic resolution (KR) of monoacylated BINOL(s) with inexpensive isobutyric anhydride in batch and flow. High selectivity values (s=29 at 0 °C) and a remarkable stability of the catalytic system in the operation conditions have been recorded for unsubstituted BINOL. No significant loss of activity/selectivity is recorded after 10 consecutive KR cycles in batch. A continuous flow process has been implemented and operated with a 100 mmol (32.8 g) sample of racemic monoacetylated BINOL in dichloromethane solution in an 84 hours experiment with a packed bed reactor containing 1 g (f=0.37 mmol.g−1) of the functional resin (s=17–21). Residence time can be decreased to 10 min with the same reactor to achieve a conversion of 58% with a selectivity factor s=17 when a more highly functionalized catalyst (f=0.88 mmol.g−1) is used. This translates into a remarkable combined productivity of 5.5 mmolprod ⋅ mmolcat−1 ⋅ h−1.

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Gram‐Scale Synthesis of 41% Efficient Single‐Component White‐Light‐Emissive Carbonized Polymer Dots with Hybrid Fluorescence/Phosphorescence for White Light‐Emitting Diodes
Authors: Wang Zifei , Liu Yang , Zhen Shijie , Li Xiaoxi , Zhang Weiguang , Sun Xun , Xu Baoyuan , Wang Xue , Gao Zhenhua , Meng Xiangeng
Published: January 2020

Fluorescent carbon dots (CDs) are compelling optical emitters to construct white light‐emitting diodes (WLEDs). However, it remains a challenge to achieve large‐scale and highly efficient single‐component white‐light‐emissive CDs suitable for WLED applications. Herein, a low cost, fast processable, environmentally friendly, and one‐step synthetic approach is developed for the preparation of gram‐scale and highly efficient single‐component white‐light‐emissive carbonized polymer dots (SW‐CPDs). It is revealed that hybrid fluorescence/phosphorescence components cooperatively contribute to the emergence of white light emission. The SW‐CPDs exhibit a record quantum yield (QY) of ≈41% for the white light emission observed in solid‐state CD systems, while the QY of the phosphorescence is ≈23% under ambient conditions. Heavy doping of N and P elements as well as presence of covalently cross‐linked polymer frameworks is suggested to account for the emergence of hybrid fluorescence/phosphorescence, which is supported by the experimental results and theoretical calculations. A WLED is fabricated by applying the SW‐CPDs on an UV‐LED chip, showing favorable white‐light‐emitting characteristics with a high luminous efficacy of 18.7 lm W−1 that is comparable to that of state‐of‐the‐art WLEDs reported before.
Identification and Single‐Cell Analysis of Viable Circulating Tumor Cells by a Mitochondrion‐Specific AIE Bioprobe
Authors: Situ Bo , Ye Xinyi , Zhao Qianwen , Mai Liyao , Huang Yifang , Wang Siqi , Chen Jing , Li Bo , He Bairong , Zhang Ye , Zou Jianjun , Tang Ben Zhong , Pan Xinghua , Zheng Lei
Published: January 2020

Liquid biopsies of cancer via single‐cell molecular profiling of circulating tumor cells (CTCs) are hampered by the lack of ideal CTC markers. In this study, it is reported that TPN, a bioprobe with aggregation‐induced emission (AIE) activity is capable of distinguishing various tumor cells from blood leukocytes based on the difference in cell mitochondria. TPN is a cell‐permeant live‐cell stain that has little effect on cell viability and integrity, enabling single‐cell DNA/RNA analysis with improved efficiency compared with traditional antibody‐based methods. Using TPN labeling, CTCs and CTC cluster are detected in the blood from patients with lung or liver cancer. The capability of TPN to identify rare tumor cells in the malignant pleural effusion samples is also demonstrated. Furthermore, RNA sequencing of single lung CTC identified by TPN is successfully performed. The findings presented here provide an antibody‐free, low‐cost, and nondisruptive approach for detection and genomic characterization of viable tumor cells based on a mitochondria‐targeting AIE luminogen. It might serve as a new tool for monitoring of genomics dynamic of tumor and unraveling the mechanisms of tumor metastasis.
Enlightened oversight of genetically engineered crops for the next generation
Authors: Herman Rod A. , Gaffney Jim , Storer Nicholas P.
Published: January 2020

Risk‐disproportionate regulatory oversight has hampered the use of genetic engineering to sustainably improve crops for the duration of a human generation (≈25 years). There is scientific consensus that transgenic breeding methods are safe. Current regulations are often driven by unfounded public fear and hamper crop improvement that is critical to meeting current environmental and nutritional needs and future food security. The public good requires progressive nations to enact policies that enlighten the oversight of modern breeding methods so that current nutritional needs can be met, future food crises can be averted, and agriculture can become more sustainable.
Economic effect of fall vs. spring plowing of forage on following potato production in Prince Edward Island, Canada
Authors: Khakbazan M. , Nyiraneza J. , Jiang Y. , Rodd V. , Huang J. , Zebarth B. , Fuller K. , Smith E. , Xie R.
Published: January 2020

Fall plowing of forage in a typical barley (Hordeum vulgare L.)–forage–potato (Solanum tuberosum L.) rotation in Prince Edward Island (PEI), Canada has led to negative environmental impacts, including soil erosion and nitrate leaching to groundwater. Data from five locations in PEI during 2009–2016 were assessed to determine the effects of delaying plow‐down of forage from early and late fall to spring on economic returns and risk of returns trade‐offs for potato producers. Factors related to fall or spring plowing such as soil erosion, nitrate leaching, planting date, effect on weeds, insects and diseases, potato harvest loss, and labor constraints were quantified. Potato yields were the same for fall and spring plowing; however, combined data for the five experiments showed late fall plowing was preferred over spring plowing for risk‐averse or neutral potato growers. Risk neutral farmers would require receiving between CAN$229 and $836 ha−1 yr−1, depending on yield loss for spring plowing due to delayed seeding, to be indifferent between fall and spring plowing options. Risk‐averse farmers at all levels of risk aversion would require being paid more than $600 ha−1 yr−1 to be indifferent between fall and spring tillage when 4–6% of yield loss for spring plowing due to delayed planting is assumed. Although spring tillage provides reductions in the risk of soil erosion and nitrate leaching, it also affects production risk and uncertainty. Therefore, we recommend farmers plow forage as late as possible in the autumn and replace it with other conservation tillage practices.
Cover crop effects on soil carbon dioxide emissions in a semiarid cropping system
Authors: Nilahyane Abdelaziz , Ghimire Rajan , Thapa Vesh R. , Sainju Upendra M.
Published: January 2020

Cover crops improve soil health and environmental quality by enhancing soil organic carbon (SOC) sequestration and nutrient cycling in agroecosystems. This study evaluated the effect of cover crops on soil CO2–C emissions, temperature, and water content during cover crop growth from April to October, 2017 and 2018. Treatments included fallow, pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea–oat (POmix), pea–canola (PCmix), pea–oat–canola (POCmix), and POC–hairy vetch (Vicia villosa L.)–forage radish (Raphanus sativus L.)–barley (Hordeum vulgare L.) (six species mixture; SSmix). The CO2–C emissions were monitored weekly from April to October each year using a portable infrared‐gas analyzer. Seasonal changes in CO2–C emissions varied with cover crops and peaked as soil temperature and water content following precipitation events. Average CO2–C emissions across sampling dates was 46–70% greater under pea than under fallow, canola, and POmix in 2017, but not different among cover crops in 2018. Although the emissions were higher than fallow, canola and POmix plots had lower CO2–C emissions than other cover crops. Pea as sole cover crop or in mixtures (PCmix, POCmix, SSmix) increased CO2–C emissions and microbial activity whereas canola and POmix mixture reduced the emissions during the period with higher precipitation.
Performance of enhanced efficiency nitrogen fertilizers in green‐harvesting sugarcane
Authors: Barth Gabriel , Otto Rafael , Mira Acácio B. , Ferraz‐Almeida Risely , Vitti André C. , Cantarella Heitor , Vitti Godofredo C.
Published: January 2020

Enhanced efficiency fertilizers (EEF) are of interest for sugarcane (Saccharum spp.) production due to the potential to reduce N losses, and improve crop yield and environmental conditions. This study was conducted to determine the effect of urea with N‐(n‐butyl) thiophosphoric triamide (NBPT) or dicyandiamide (DCD) on NH3 volatilization and sugarcane yield. The NH3 volatilization, the foliar concentration of N and S, and yield of stalk and pol were monitored in two field trials testing six N sources (urea; urea + NBPT; urea + DCD; ammonium sulfate [AS]; ammonium nitrate [AN]; ammonium sulfate nitrate), and three N rates (50, 100, and 150 kg ha−1). The N losses from urea totaled 22 and 18% in Sites 1 and 2, respectively. Treating urea with NBPT reduced NH3 volatilization by 60%. Sugarcane yield increased 8.8; 11.6; and 16.0 Mg ha−1 (Site 1), and 4.5, 9.3, and 14.2 Mg ha−1 (Site 2) with the application of 50, 100, and 150 kg ha−1 N as compared to control, respectively. All N sources increased yields, demonstrating similar efficiency for sugarcane production. Green harvesting sugarcane cultivated in sandy soils with low organic matter concentration is highly responsive to N, showing similar efficiency between EEF and conventional N fertilizers.
Applied use of growing degree days to refine optimum times for nitrogen stress sensing in winter wheat
Authors: Dhillon Jagmandeep S. , Figueiredo Bruno M. , Eickhoff Elizabeth M. , Raun William R.
Published: January 2020

Variable influence of the environment on early‐season plant growth leads to similarly variable yield levels from year to year. This study was conducted to determine the ideal point in the growing season when normalized difference vegetation index (NDVI) sensor readings were highly correlated with grain yield. For each site‐year, NDVI readings were collected at least seven times from December through April. Readings were collected from two long‐term experiments where an N response was expected in plots that historically received different N rates. The number of days from planting to sensing where growing degree days (GDD) were more than 0 (GDD > 0) was tabulated by site‐year for all dates when NDVI data were collected. The r2 was computed for NDVI versus final grain yield at all sensing dates and plotted against the respective GDD > 0 when readings were taken. Linear plateau models were used to determine the point when the r2 peaked. Averaged over 3 yr (2016–2018), the optimum GDD > 0 needed to predict grain yield using NDVI in both long‐term trials was between 97 and 112. Use of the GDD > 0 as a numeric metric to delineate the best time and date to collect NDVI readings and predict yield potential can then be used to formulate accurate midseason fertilizer N rates. Adhering to quantitative GDD > 0 data is much more reliable than using subjective morphological scales. These critical GDD values can be reported on a day‐to‐day, by‐location basis (mesonet.org) for in‐season producer use.
Characterization of root traits for improvement of spring wheat in the Pacific Northwest
Authors: Ghimire Bikash , Hulbert Scot H. , Steber Camille M. , Garland‐Campbell Kim , Sanguinet Karen A.
Published: January 2020

Understanding the genetic basis of root traits provides essential information on a largely untapped resource for crop improvement, as roots are instrumental for the uptake of water and nutrients. However, breeding for improved root traits is challenging due to laborious and time‐consuming root phenotyping in soil. Our studies sought to uncover spatiotemporal root‐growth dynamics of mature plant root systems in five spring wheat (Triticum aestivum L.) cultivars, Louise, Alpowa, Hollis, Drysdale, and Dharwar Dry, and a facultative spring landrace, AUS28451 using the in situ minirhizotron technique. The 2‐yr greenhouse study revealed that the root system grows rapidly after early node elongation to gain maximum size during anthesis, after which root growth slows and transitions to senescence. We were able to detect quantifiable differences among wheat cultivars in root traits in both 5‐d old seedlings and root systems at anthesis. Furthermore, the positive correlation of the observed root traits with grain yield and the consistency in root traits observed using minirhizotrons and through extraction of young and mature root systems has reinforced the experimental results. A negative correlation was found between root number, area, and length and root diameter. We found that the spring wheat cultivars, AUS28451, Dharwar Dry, and Alpowa, had increased root number, area, and length, but also increased time to heading. The results from this study can be further leveraged to screen breeding lines for root traits of interest, as well as assess the heritability of root traits for dryland farming in the inland Pacific Northwest.
Modeling of an industrial scale hydrodynamic cavitation multiphase reactor for Prileschajew epoxidation
Authors: Wu Zhenyu , Cai Jinjin , Liu Zhonghui , Wu Lihang , Liang Xiaojiang , Xie Qinglong , Lu Meizhen , Yu Fengwen , Nie Yong , Ji Jianbing
Published: January 2020

The hydrodynamic cavitation multiphase reactor (HCMR) is emerging as a promising alternative for the intensification of liquid–liquid heterogeneous reactions, but research on HCMR modeling is lacking. In this article, an HCMR model was developed using Prileschajew epoxidation as the model system. First, based on experimental measurements of oil/water two‐phase flow downstream of hydrodynamic cavitation devices, semiempirical correlations were proposed to describe the droplet size and droplet size distribution (DSD) as functions of flow conditions and geometry parameters. Then, with boundary conditions calculated by the DSD correlation, a droplet dynamics simulation in a reaction tank was performed by computational fluid dynamics coupled with population balance model to obtain the two‐phase interfacial area. Finally, the acquired reactor model was substituted into an overall kinetic model, to simulate the epoxidation reaction in HCMR. Model predictions were verified by experimental results measured on an industrial scale HCMR.
A heavy metal baseline score predicts outcome in acute myeloid leukemia
Authors: Ohanian Maro , Telouk Philippe , Kornblau Steven , Albarede Francis , Ruvolo Peter , Tidwell Rebecca S. S. , Plesa Adriana , Kanagal‐Shamanna Rashmi , Matera Eva‐Laure , Cortes Jorge , Carson Arch , Dumontet Charles
Published: January 2020

Despite abundant epidemiological data linking metals to leukemia and other cancers, baseline values of toxic and essential metals in patients with leukemia and the clinical impact of these metals remain unknown. Thus, we sought to quantify metal values in untreated patients with acute myeloid leukemia (AML) and controls and determine the impact of metal values on AML patients' survival. Serum samples from patients with untreated AML and controls at Hospices Civils de Lyon were analyzed and compared for trace metals and copper isotopic abundance ratios with inductively coupled plasma mass spectrometry. Survival analysis was performed as a function of metal values, and a multi‐metal score was developed for patients with AML. Serum samples were collected from 67 patients with untreated AML and 94 controls. Most patients had intermediate‐risk cytogenetics (63.1%) without FLT3internal tandem duplication mutations (75.6%) orNPM1mutations (68.1%). Most metal values differed significantly between AML and control groups. Patients with lower magnesium and higher cadmium values had the worst survival rates, with only 36% surviving at 6 months (P= .001). The adverse prognostic effect of this combination was maintained on multivariate analysis. Based on this, we developed a novel metal score, which accounts for multiple relative abnormalities in the values of five toxic and five essential metals. Patients with a higher metal score had significantly worse survival, which was maintained on multivariate analysis (P= .03). This baseline metal scoring system was also prognostic when we applied it to a separate population of front‐line AML patients.
Regioselective Carboiodination of Styrenes: N‐Iodosuccinimide Affords Complete Reaction Regioselectivity
Authors: Goto Mayuki , Maejima Saki , Yamaguchi Eiji , Itoh Akichika
Published: January 2020

In organic synthesis, the regioselective bifunctionalization of olefins remains an unmet challenge. In this study, the cationic iodine‐mediated complete β‐selective carboiodoination of styrene and styrene‐like compounds with Meldrum's acid was achieved. The reaction, thus developed, proceeded with the formation of a C−C bond at the olefin's β‐position and a C−I bond at its β‐position, via a single‐step reaction between Meldrum's acid and an iodonium intermediate. The developed strategy suppresses the formation of undesired side‐reactions, resulting from α‐selective carboiodoination. To demonstrate the developed methodology's potential, synthetic transformations were also performed, starting from the generated carboiodinated products.
Cardiac arrest during hemodialysis: a survey of five Japanese hospitals
Authors: Tanaka Taku , Nomura Yu , Hirama Chie , Takamatsu Yuka , Wakatake Haruaki , Suzuki Toshihiko , Kawarazaki Hiroo , Sakurada Tsutomu , Fujitani Shigeki , Taira Yasuhiko
Published: January 2020

Aim

Intraprocedural cardiac arrest is a serious complication among patients receiving hemodialysis. However, the frequency and reaction to these events remain unclear. This study aimed to explore the clinical picture of cardiac arrest during hemodialysis.

Methods

Ten cardiac arrests that had occurred during 217,984 hemodialysis treatments in five Japanese hospitals, between 2008 and 2017, were reviewed. We investigated the underlying disease, vital signs, emergency responses, and outcomes using patient medical records.

Results

The cardiac arrest rate ranged from 1.1 to 7.5 per 100,000 hemodialysis sessions. All included cases of cardiac arrest occurred in a hemodialysis unit and had been witnessed and reported by supervising clinicians. The initial rhythm was ventricular fibrillation/ventricular tachycardia in six patients (60%) and pulseless electrical activity/asystole in four patients (40%). Seven (70%) patients showed a return of spontaneous circulation (ROSC), and two (20%) patients were discharged with a cerebral performance category score of 1. There was a statistically significant difference in the ROSC rate (P = 0.048) only in the event of an emergency call. The SpO2 and respiratory rates had not been recorded in six patients. There was no significant difference in ROSC between initial rhythms of ventricular fibrillation/ventricular tachycardia and pulseless electrical activity/asystole.

Conclusion

We evaluated the frequency of cardiac arrest during hemodialysis. Overall assessment including respiratory status is needed at initiation of hemodialysis. In case of a sudden change in a patient’s status, high‐quality resuscitation treatment that includes an emergency call can improve prognosis.
Molecular Porous Photosystems Tailored for Long‐Term Photocatalytic CO2 Reduction
Authors: Wisser Florian M. , Duguet Mathis , Perrinet Quentin , Ghosh Ashta C. , Alves‐Favaro Marcelo , Mohr Yorck , Lorentz Chantal , Quadrelli Elsje Alessandra , Palkovits Regina , Farrusseng David , Mellot‐Draznieks Caroline , de Waele Vincent , Canivet Jérôme
Published: January 2020

The molecular‐level structuration of two full photosystems into conjugated porous organic polymers is reported. The strategy of heterogenization gives rise to photosystems which are still fully active after 4 days of continuous illumination. Those materials catalyze the carbon dioxide photoreduction driven by visible light to produce up to three grams of formate per gram of catalyst. The covalent tethering of the two active sites into a single framework is shown to play a key role in the visible light activation of the catalyst. The unprecedented long‐term efficiency arises from an optimal photoinduced electron transfer from the light harvesting moiety to the catalytic site as anticipated by quantum mechanical calculations and evidenced by in situ ultrafast time‐resolved spectroscopy.
Triple‐Helix‐Stabilizing Effects in Collagen Model Peptides Containing PPII‐Helix‐Preorganized Diproline Modules
Authors: Maaßen Andreas , Gebauer Jan M. , Theres Abraham Elena , Grimm Isabelle , Neudörfl Jörg‐Martin , Kühne Ronald , Neundorf Ines , Baumann Ulrich , Schmalz Hans‐Günther
Published: January 2020

Collagen model peptides (CMPs) serve as tools for understanding stability and function of the collagen triple helix and have a potential for biomedical applications. In the past, interstrand cross‐linking or conformational preconditioning of proline units through stereoelectronic effects have been utilized in the design of stabilized CMPs. To further study the effects determining collagen triple helix stability we investigated a series of CMPs containing synthetic diproline‐mimicking modules (ProMs), which were preorganized in a PPII‐helix‐type conformation by a functionalizable intrastrand C2 bridge. Results of CD‐based denaturation studies were correlated with calculated (DFT) conformational preferences of the ProM units, revealing that the relative helix stability is mainly governed by an interplay of main‐chain preorganization, ring‐flip preference, adaptability, and steric effects. Triple helix integrity was proven by crystal structure analysis and binding to HSP47.
Heavy‐Atom Tunneling in Organic Reactions
Authors: Castro Claire , Karney William L.
Published: January 2020

In the past few years, numerous investigations have been reported on the role of heavy‐atom tunneling in the area of pericyclic reactions, π‐bond‐shifting, and other processes. These studies illustrate unique strategies for the experimental detection of heavy‐atom tunneling and the increased use of calculations to predict it. This Minireview focuses primarily on carbon tunneling in ground‐state processes but also highlights nitrogen tunneling and the first example of excited‐state heavy‐atom tunneling. Salient features of these reactions along with potential limitations are discussed, as well as challenges and directions for future investigation.
Mechanical Force Induces Ylide‐Free Cycloaddition of Nonscissible Aziridines
Authors: Jung Sangmin , Yoon Hyo Jae
Published: January 2020

The application of aziridines as nonvulnerable mechanophores is reported. Upon exposure to a mechanical force, stereochemically pure nonactivated aziridines incorporated into the backbone of a macromolecule do not undergocis–transisomerization, thus suggesting retention of the ring structure under force. Nonetheless, aziridines react with a dipolarophile and seem not to obey conventional reaction pathways that involve C−C or C−N bond cleavage prior to the cycloaddition. Our work demonstrates that a nonvulnerable chemical structure can be a mechanophore.
Electrochemiluminescence Waveguide in Single Crystalline Molecular Wires
Authors: Guo Weiliang , Ding Hao , Zhou Ping , Wang Yafeng , Su Bin
Published: January 2020

Here we report the first observation of active waveguide of electrochemiluminescence (ECL) in single crystalline molecular wires self‐assembled from cyclometalated iridium(III) complexes, namely tris(1‐phenylisoquinoline‐C2, N) (Ir(piq)3). Under dark conditions, the molecular wires deposited on the electrode surface can act as both ECL emitters and active waveguides. As revealed by ECL microscopy, they exhibit the typical characteristics of optical waveguides, transmitting ECL and generating much brighter ECL emission at their terminals. Moreover, self‐generated ECL can be confined inside the molecular wire and propagates along the longitudinal direction as far as ≈100 μm to the terminal out of touch with the electrode. Therefore, this one‐dimensional crystalline molecular wire‐based waveguide offers the opportunity to switch the electrochemically generated ECL to remote light emission in non‐conductive regions and is promising for contactless electrochemical analysis and study of (bio)chemical systems.
Development of a Cross‐Conjugated Vinylogous [4+2] Anionic Annulation and Application to the Total Synthesis of Natural Antibiotic (±)‐ABX
Authors: Huang Jing‐Kai , Shia Kak‐Shan
Published: January 2020

The cross‐conjugated vinylogous [4+2] anionic annulation has been newly developed, the cascade process of which has a high preference for regiochemical control and chemoselectivity, giving rise to exclusively Michael‐type adducts in moderate to high yields (up to 94 %, 35 examples). By making use of this approach as a key operation, the first total synthesis of natural antibiotic ABX, in racemic form, has been successfully achieved in a concise 7‐step sequence with an overall yield of about 20 %.
Multi‐Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods
Authors: Glaser Felix , Kerzig Christoph , Wenger Oliver S.
Published: January 2020

The energy of visible photons and the accessible redox potentials of common photocatalysts set thermodynamic limits to photochemical reactions that can be driven by traditional visible‐light irradiation. UV excitation can be damaging and induce side reactions, hence visible or even near‐IR light is usually preferable. Thus, photochemistry currently faces two divergent challenges, namely the desire to perform ever more thermodynamically demanding reactions with increasingly lower photon energies. The pooling of two low‐energy photons can address both challenges simultaneously, and whilst multi‐photon spectroscopy is well established, synthetic photoredox chemistry has only recently started to exploit multi‐photon processes on the preparative scale. Herein, we have a critical look at currently developed reactions and mechanistic concepts, discuss pertinent experimental methods, and provide an outlook into possible future developments of this rapidly emerging area.
Cytotoxic performances of new anionic cyclometalated Pt(II) complexes bearing chelated O^O ligands
Authors: Ionescu Andreea , Caligiuri Rossella , Godbert Nicolas , Ricciardi Loredana , La Deda Massimo , Ghedini Mauro , Ferri Nicola , Lupo Maria Giovanna , Facchetti Giorgio , Rimoldi Isabella , Aiello Iolinda
Published: January 2020

The in vitro biological activity towards the MDA‐MB‐231 triple‐negative breast cancer cell line of two different series of anionic Pt(II) organometallic complexes was tested. For the first time, cytotoxic activity of anionic Pt(II) complexes has been observed. The anionic compounds of general formula NBu4[(C^N)Pt(O^O)], where (C^N) represents the cyclometalated form of 2‐phenylpyridine (H(PhPy)), 2‐thienylpyridine (H(Thpy)) or 2‐benzo[h]quinoline (H(Bzq)), feature two different (O^O) chelated ligands: tetrabromocatechol [BrCat]2− (1–3) or alizarine [Aliz]2− (4–6). Complexes 1–6 displayed a significant cytotoxic effect against the studied cell line (IC50 range of 1.9–52.8 μM). For BrCat‐containing complexes 1–3, the biological activity was independent of the nature of the coordinated (C^N) ligand. In contrast, in the case of 4–6, the cytotoxicity (significantly high for 4) was concomitantly induced by the presence of either the PhPy or the [Aliz]2− ligand. Since complexes 1–6 are emissive in solution, the potential use of 4 as a theranostic agent was investigated using confocal analysis. The fluorescence signal from MDA‐MB‐231 cells incubated with 4 indicated the localization of the compound into the cytosol region.
Polycaprolactone blends for fracture fixation in low load‐bearing applications
Authors: Bou‐Francis Antony , Piercey Marta , Al‐Qatami Omar , Mazzanti Gianfranco , Khattab Rabie , Ghanem Amyl
Published: January 2020

There is a need to replace surgical plates and screws in orthopedic surgery. Absorbable polymers are an alternative to metal where load bearing is of a less concern. Polycaprolactone (PCL) is biocompatible, yet it has low mechanical strength and its surface chemistry does not promote cell adhesion. The objective of this work was to create PCL adhesive blends with poly(glycolic) acid (PGA), thermoplastic starch (TPS), chitosan, and tricalcium phosphate (TCP) to be used as potential fracture fixation devices. The differential scanning calorimetry (DSC) data showed that the primary melting points (T
m1 °C) of blends were often lower than PCL, with the exception of chitosan blends, which may indicate an improvement for surgical use. PCL/PGA blends showed secondary and tertiary melting points (T
m) and enthalpies (ΔH
m) indicating poor miscibility of PGA in the blends. The binary PCL/TCP mixture has a higher enthalpy compared to the binary PCL/PGA blend, but the secondary melting temperature is lower in ternary mixtures. Ternary blends of PCL/PGA/TCP, however, retained the adhesive strength of the parent PCL adhesive while having an improvement in hydrophilicity. These blends are recommended for fracture fixation devices especially in low load‐bearing applications such as maxillofacial surgery, orthopedics, and neurosurgery. © 2020 Wiley Periodicals Inc. J. Appl. Polym. Sci. 2020, 137, 48940.
Effects of sorbitol and formamide plasticizers on molecular motion in corn starch studied using NMR and DMTA
Authors: Baran A. , Vrábel P. , Kovaľaková M. , Hutníková M. , Fričová O. , Olčák D.
Published: January 2020

Mechanical and thermal properties of composite polymer materials strongly depend on their local structure and molecular dynamics which can be effectively studied by the solid‐state nuclear magnetic resonance (NMR) techniques. In the present paper, the influence of formamide (F) and sorbitol (S) plasticizers on molecular motion in thermoplastic starch (TPS) was studied using solid‐state NMR spectroscopy and dynamic mechanical thermal analysis (DMTA). DMTA measurements carried out for formamide‐ (F‐TPS) and sorbitol‐plasticized (S‐TPS) corn starches indicated heterogeneous plasticizer distribution of plasticizer‐rich and starch‐rich phases within the samples. The single pulse and cross‐polarization13C NMR spectra measured for both plasticized starches confirmed the amorphous character of their structure and distinctly different chain mobility supported by the values of13C spin–lattice relaxation times. The results of the analysis of broad line and magic angle spinning1H NMR spectra are in accordance with the results of DMTA measurements, revealing lower mobility of starch chains within S‐TPS in comparison to F‐TPS. Crosslinking of the starch chains with sorbitol molecules was suggested as being responsible for the lower mobility of the starch chains in S‐TPS. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48964.
Interdiffusion during film formation of ionically cross‐linked acrylics investigated with Förster resonance energy transfer (FRET)
Authors: Wahdat Hares , Gerst Matthias , Möbius Stephan , Adams Jörg
Published: January 2020

Polymer interdiffusion is crucial to obtain continuous films from aqueous polymer dispersions. Here, interdiffusion in films from dispersions of acrylates which were ionically cross‐linked prior to film formation was studied by Förster resonance energy transfer analysis. Dispersions of copolymers of n‐butyl acrylate, methacrylic acid, and zinc dimethacrylate (ZnDMA) were investigated. ZnDMA was used as a co‐monomer to ionically cross link the polymers during the synthesis. Ionic cross‐linking does not prevent interdiffusion even at high gel contents. Interdiffusion data were compared with results of tensile tests on final films. Films of ionically cross‐linked polymers fracture at both higher stress and strain than films of covalently cross‐linked polymers. Further interdiffusion studies addressed effects of temperature and humidity. Both increased temperature and humidity accelerate interdiffusion of ionically cross‐linked polymers. Thus, using ZnDMA allows for preparing dispersions which can form continuous films. Also, no volatile organic compounds are released during the film formation. © 2020 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48972.
Composite nonlinear feedback with dynamic event‐triggered mechanism for control systems in the presence of saturation nonlinearity
Authors: Zuo Zhiqiang , Cheng Haorui , Xie Pengfei , Wang Yijing , Li Hongchao
Published: January 2020

A composite nonlinear feedback (CNF) control with dynamic event‐triggered strategy for saturated systems is considered in this paper. The CNF control is introduced to improve the system response speed and reduce the overshoot under disturbances. The dynamic event‐triggered mechanism (DETM) is utilized to save more communication resources. The focus of this paper is to achieve the asymptotic tracking of saturated systems by combining DETM with CNF control. A criterion is presented to guarantee that the system can track the reference input signal asymptotically. Zeno behavior is eliminated by proving the minimum time interval is greater than zero. Finally, simulations are carried out to verify the correctness of the proposed results.
Gassing Behavior of High‐Entropy Oxide Anode and Oxyfluoride Cathode Probed Using Differential Electrochemical Mass Spectrometry
Authors: Breitung Ben , Wang Qingsong , Schiele Alexander , Tripković Đorđije , Sarkar Abhishek , Velasco Leonardo , Wang Di , Bhattacharya Subramshu S. , Hahn Horst , Brezesinski Torsten
Published: January 2020

Multicomponent materials may exhibit favorable Li‐storage properties because of entropy stabilization. While the first examples of high‐entropy oxides and oxyfluorides show good cycling performance, they suffer from various problems. Here, we report on side reactions leading to gas evolution in Li‐ion cells using rock‐salt (Co0.2Cu0.2Mg0.2Ni0.2Zn0.2)O (HEO) or Li(Co0.2Cu0.2Mg0.2Ni0.2Zn0.2)OF (Li(HEO)F). Differential electrochemical mass spectrometry indicates that a robust solid‐electrolyte interphase layer is formed on the HEO anode, even when using an additive‐free electrolyte. For the Li(HEO)F cathode, the cumulative amount of gases is found by pressure measurements to depend strongly on the upper cutoff potential used during cycling. Cells charged to 5.0 V versus Li+/Li show the evolution of O2, H2, CO2, CO and POF3, with the latter species being indirectly due to lattice O2 release as confirmed by electron energy loss spectroscopy. This result attests to the negative effect that lattice instability at high potentials has on the gassing.
Biosynthesis and Structure–Activity Relationship Investigations of the Diazeniumdiolate Antifungal Agent Fragin
Authors: Sieber Simon , Daeppen Christophe , Jenul Christian , Mannancherril Vidya , Eberl Leo , Gademann Karl
Published: January 2020

Only a few natural products incorporating a diazeniumdiolate moiety have been isolated, and these compounds usually display a broad range of biological activities. Only recently has the first diazeniumdiolate natural product biosynthetic gene cluster been identified in Burkholderia cenocepacia H111, which produces the fungicide (−)‐fragin and the signal molecule rac‐valdiazen. In this study, l‐valine was identified as the initial substrate of (−)‐fragin biosynthesis with the aid of feeding experiments using isotopically labelled amino acid. The formation of the diazeniumdiolate was chemically studied with several proposed intermediates. Our results indicate that the functional group is formed during an early stage of the biosynthesis. Furthermore, an oxime compound was identified as a degradation product of (−)‐fragin and was also observed in the crude extract of the wild‐type strain. Moreover, a structure–activity relationship analysis revealed that each moiety of (−)‐fragin is essential for its biological activity.
Clar Rules the Electronic Properties of 2D π‐Conjugated Frameworks: Mind the Gap
Authors: Strutyński Karol , Mateo‐Alonso Aurelio , Melle‐Franco Manuel
Published: January 2020

The key electronic properties of a family of 2D frameworks structurally convergent with holey graphenes were studied. The bandgap of these materials decreases monotonically with size, showing a common trend with anthracenes and kekulenes. This was rationalized by Clar's sextet rule, which reveals a direct relationship between the molecular systems and the 2D frameworks. In addition, a detailed benchmark against experimental data showcased the high quality of the models, which reproduce accurately available electronic properties. Overall, it was shown that DFT can be used to screen and understand the intrinsic bandgaps and electrochemistry potentials for technological applications prior to the synthesis of π‐conjugated porous materials.
Facile Access to Substituted 1,4‐Diaza‐2,3‐Diborinines
Authors: Thiess Torsten , Ernst Moritz , Kupfer Thomas , Braunschweig Holger
Published: January 2020

Several bis(dimethylamino)‐substituted 1,4‐diaza‐2,3‐diborinines (DADBs) were synthesized with variable substituents at the backbone nitrogen atoms. By reaction with HCl or BX3 (X=Br, I), these species were successfully converted into their synthetically more useful halide congeners. The high versatility of the generated B−X bonds in further functionalization reactions at the boron centers was demonstrated by means of salt elimination (MeLi) and commutation (NMe2 DADBs) reactions, thus making the DADB system a general structural motif in diborane(4) chemistry. A total of 18 DADB derivatives were characterized in the solid state by X‐ray diffraction, revealing a strong dependence of the heterocyclic bonding parameters from the exocyclic substitution pattern at boron. According to our experiments towards the realization of a Dipp‐substituted, sterically encumbered DADB, the mechanism of DADB formation proceeds via a transient four‐membered azadiboretidine intermediate that subsequently undergoes ring expansion to afford the six‐membered DADB heterocycle.
Zinc(II)–Organic Framework Films with Thermochromic and Solvatochromic Applications
Authors: Lee Li‐Wei , Chi Heng‐Yu , Kao Ya‐Chuan , Hung Ting‐Hsiang , Chiou Da‐Shiuan , Lee Gene‐Hsiang , Peng Shie‐Ming , Kang Dun‐Yen , Wang Chih‐Min , Lu Kuang‐Lieh
Published: January 2020

Multiple‐stimuli‐responsive photoluminescence films based on a ZnII–organic framework, {[Zn2(Htpim)(3,4‐pydc)2]⋅4 DMF⋅4 H2O}n (1, Htpim=2,4,5‐tri(4‐pyridyl)imidazole, 3,4‐H2pydc=3,4‐pyridinedicarboxylic acid), were fabricated. This compound consisted of a 2D corrugated layer, {Zn(3,4‐pydc)}n, which was further pillared using a Y‐shaped pillar N‐donor ligand (Htpim) to form a 3D‐pillared‐layer framework with 1D open channels. The rectangular channels in the as‐synthesized compound are fully occupied by guest DMF and H2O molecules. The framework exhibits instant and reversible thermochromic properties corresponding to the removal of different H2O and DMF guest molecules as temperature increases. The pale‐yellow crystal undergoes significant redshifting to a greenish emission centered at 530 nm. Compound 1 also showed remarkable solvatochromic effects in the presence of various organic solvents without affecting its structural integrity. In addition, polycrystalline MOF films were grown on an α‐Al2O3 support for switchable and fast‐response thermochromic and solvatochromic sensors.
Degradation of surfactant used in iron mining by oxidation technique: Fenton, photo‐Fenton, and H2O2/UV—A comparative study
Authors: Falconi Isabela B. A. , Baltazar Marcela dos P. G. , Espinosa Denise C. R. , Tenório Jorge Alberto S.
Published: January 2020

Reuse of water in mining helps reduce the volume of tailings directed to dams, avoiding overloads and ruptures, as occurred in Brumadinho, Brazil. Water reuse in mining requires treatment mainly for removing the surfactant substances used. Photo‐Fenton and UV/H2O2 showed 96% to 98% degradation results of anionic surfactants within 5 minutes, suggesting this technique is faster than biological systems that can take days. This paper aims to study the degradation of a surfactant used in the flotation process by UV/H2O2, Fenton, and photo‐Fenton oxidation techniques. The compound was characterized by FTIR and MALDI‐TOF. In degradation experiments, the variation in reactants concentrations was evaluated with hydrogen peroxide, iron sulphate heptahydrate, and oxalic acid. We used a synthetic solution of surfactant in the reverse flotation of ore with 180 mg/L. The reaction was monitored with TOC analysis and a spectrophotometer throughout the reaction. The UV/H2O2 and Fenton system were studied by varying peroxide and iron concentrations, with 120 minute tests. Additionally, photo‐Fenton concentrations, the pH variation (1.5‐8.0), temperature (15°C, 21°C, and 60°C), and time were evaluated. The results showed the most efficient degradation was that using photo‐Fenton, which achieved total TOC removal using 4500 mg/L of peroxide and 364 mg/L of iron for 330 minutes, while the UV/H2O2 system achieved 29% and 49% TOC removal of the Fenton. It is verified that the oxidative processes can be applied to degrade the surfactants present in the water recovered from the flotation processes.
Development of an image evaluation method for skin color distribution in facial images and its application: Aging effects and seasonal changes of facial color distribution
Authors: Kikuchi Kumiko , Mizokami Yoko , Egawa Mariko , Yaguchi Hirohisa
Published: January 2020

In this article, we present an evaluation method for the skin color distribution in the face area. Unlike previous methods that extract a specific area, our method subdivides the entire face into small regions and analyzes detailed, per‐frame textures. Our evaluation method for skin color distribution is based on facial feature points and includes segmentation that takes into account the facial skeleton and muscle orientation. The use of facial feature points enables a comparison at relatively equal positions on the face without depending on the shape or size of the individual's face. Our evaluation method is versatile, and as an application, we clarified age‐specific features and seasonal variations of facial color distribution. As a result of applying this evaluation method to the facial images of women aged 20 to 78 years, we confirmed that the lightness of the face decreased as age increased. In particular, the decrease in lightness was remarkable in the region along the cheekbone, from the temple to the center of the cheek. Furthermore, we analyzed the seasonal changes of melanin distribution in the face area. This showed that the melanin index increased particularly in the cheekbone area in the summer when the influence of ultraviolet rays became large. Our novel methodology and the data presented in this article will be useful in various fields, such as dermatology, cosmetics, and computer vision.
Visible‐NIR Photodetectors Based on Low‐Dimensional GeSe Micro‐Crystals: Designed Morphology and Improved Photoresponsivity
Authors: Zhao Feiyu , Luo Xue , Liu Lixiang , Lv Jianhang , Fan Xianping , Qiao Xvsheng , Xu Yang , Kienle Lorenz , Zhang Xianghua , Qian Guodong
Published: January 2020

GeSe micro‐sheets and micro‐belts have been synthesized by a facile one‐pot wet chemical method in 1‐octadecene solvent and oleic acid solvent, respectively. The adsorption of more oleic acid molecules on the (002) plane promoted growth along [010] direction of the GeSe micro‐belts and limited carrier transport in this direction, resulting in higher carrier concentration and mobility of the GeSe micro‐belts. The performance of the photodetectors based on the single GeSe micro‐sheet and the single GeSe micro‐belt was investigated under illumination at 532 nm, 980 nm and 1319 nm. Both, photodetectors based on a single GeSe micro‐sheet and a single GeSe micro‐belt, exhibit a high photoresponse, short response/recovery times, and long‐term durability. Moreover, the photodetector based on a single GeSe micro‐belt displays a broadband response with a high responsivity (5562 A/W at 532 nm, 1546 A/W at 980 nm) and detectivity (3.01×1012 Jones at 532 nm, 8.38×1011 Jones at 980 nm). These excellent characteristics render single GeSe micro‐belts very interesting for use as highly efficient photodetectors, especially in the NIR region.
Belowground interactions differ between sympatric desert shrubs under water stress
Authors: Zhang Zhengzhong , Shan Lishan , Li Yi , Wang Yang
Published: January 2020

Understanding the relationships among species is central to ecological research; however, many knowledge gaps remain regarding how desert plant species interact. In the present study, we assessed the effect of rainfall on the belowground interactions and root morphology of two desert shrubs, Reaumuria soongorica (Tamaricaceae) and Salsola passerina (Chenopodiaceae), from three communities with similar landforms and soil environments. The roots of both R. soongorica and S. passerina were deeper when grown together than grown singly. Interestingly, the belowground biomass of R. soongorica was higher, but the belowground biomass of S. passerina was lower when grown together than when grown alone. This suggests that S. passerina benefitted from the association with R. soongorica. When grown together under conditions of low rainfall, the roots of R. soongorica were deeper than those of S. passerina, which suggests that R. soongorica is more robust than S. passerina when subjected to periods of decreased rainfall. We concluded that the symbiotic relationship between these two shrub species can lead to deeper roots and that the plants are affected by rainfall availability. Combined with the output results of climate change models, we speculated that the distribution area of these two species will expand to the west, which has important implications on how the interactions of other desert species may change in response to climate variability.