bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facile Synthesis of a Stable Dihydroboryl {BH2}− Anion
Authors: Arrowsmith Merle , Mattock James D. , Hagspiel Stephan , Krummenacher Ivo , Vargas Alfredo , Braunschweig Holger 
Published: September 2018

AbstractWhile the one‐electron reduction of (CAACMe)BH2Br (CAACMe=1‐(2,6‐diisopropylphenyl)‐3,3,5,5‐tetramethylpyrrolidin‐2‐ylidene) yields a hydride‐shift isomer of the corresponding tetrahydrodiborane, a further reversible reduction leads to the first stable parent boryl anion, [(CAACMe)BH2]−, which acts as a powerful boron nucleophile.
Identification of sieve elements and companion cell protoplasts by a combination of brightfield and fluorescence microscopy
Authors: Kaur Prabhjot , Gonzalez Pedro , Dutt Manjul , Etxeberria Ed 
Published: September 2018

Premise of the StudyPhloem‐limited diseases are becoming increasingly pervasive, threatening the existence of crops worldwide. Studies of phloem diseases are complicated by the inaccessibility of the phloem tissue. Phloem cells are located deep inside the plant body, are interspersed with other cell types, are among the smallest cells in the plant kingdom, and make up a small percentage of the total cell population in a plant. These properties make phloem cells difficult to investigate.MethodsWe used leaf midrib protoplasts and a combination of organelle‐specific dyes including Neutral Red (acidic compartments), MitoTracker Green (mitochondria), Hoechst 3342 (nucleus), and chloroplast autofluorescence. We examined the protoplasts under light and fluorescence microscopy.ResultsWhen observed using brightfield and fluorescence microscopy, sieve element protoplasts were distinguished by the lack of vacuole and a nucleus, and by containing various mitochondria. Companion cells showed a dense cytoplasm and various small vacuoles. They also revealed their characteristic large nucleus and abundant mitochondria.DiscussionWe present evidence that a combination of organelle‐specific dyes and autofluorescence allows for the identification of sieve elements and companion cell protoplasts from citrus leaf tissue.
Photolithographically Patterned Hydrogels with Programmed Deformations
Authors: Li Chen Yu , Hao Xing Peng , Wu Zi Liang , Zheng Qiang 
Published: September 2018

AbstractProgrammed deformations are widespread in nature, providing elegant paradigms to design self‐morphing materials with promising applications in biomedical devices, flexible electronics, soft robotics, etc. In this emerging field, hydrogels are an ideal material to investigate the deformation principle and the structure‐deformation relationship. One crucial step is to construct heterogeneous structures in a facile yet effective way. Herein, we provide a focus review on different deformation modes and corresponding structural features of hydrogels. Photolithography is a versatile approach to control the outer shape of the hydrogel and spatial distribution of the component in the hydrogel, endowing the patterned hydrogels with programmed internal stress and thus controllable deformations. Specifically, cooperative deformations take place in periodically patterned hydrogels with in‐plane gradients, and multiple morphing structures are formed in one patterned hydrogel using selective preswelling to direct the buckling of each unit. The structural control strategy and deformation principles should be applicable to other materials with broad applications in diverse areas.
Composite Finite‐time Convergent Guidance Law for Maneuvering Targets with Second‐order Autopilot Lag
Authors: Wu Junxiong , Wang Hui , He Shaoming , Lin Defu 
Published: September 2018

AbstractThis paper aims to develop a new finite‐time convergent guidance law for intercepting maneuvering targets accounting for second‐order autopilot lag. The guidance law is applied to guarantee that the line of sight (LOS) angular rate converges to zero in finite time and results in a direct interception. The effect of autopilot dynamics can be compensated based on the finite‐time backstepping control method. The time derivative of the virtual input is avoided, taking advantage of integral‐type Lyapunov functions. A finite‐time disturbance observer (FTDOB) is used to estimate the lumped uncertainties and high‐order derivatives to improve the robustness and accuracy of the guidance system. Finite‐time stability for the closed‐loop guidance system is analyzed using the Lyapunov function. Simulation results and comparisons are presented to illustrate the effectiveness of the guidance strategy.
Determination of Penicillium griseofulvum‐oriented pyripyropene A, a selective inhibitor of acyl‐coenzyme A:cholesterol acyltransferase 2, in mouse plasma using liquid chromatography–tandem mass spectrometry and its application to pharmacokinetic studies
Authors: Lee Kyeong‐Ryoon , Chae Song‐Hee , Kim Min Ju , Chae Yoon‐Jee , Lee Myung Yeol , Lee Chang Woo , Kang Jong Soon , Yoon Won‐Kee , Won Young‐Suk , Lee Kihoon , Moon Og‐Sung , Kim Young‐Kook , Kim Hyoung‐Chin 
Published: September 2018

AbstractIn this study, we developed a method for the determination of Penicillium griseofulvum‐oriented pyripyropene A (PPPA), a selective inhibitor of acyl‐coenzyme A:cholesterol acyltransferase 2, in mouse and human plasma and validated it using liquid chromatography–tandem mass spectrometry. Pyripyropene A (PPPA) and an internal standard, carbamazepine, were separated using a Xterra MS C18 column with a mixture of acetonitrile and 0.1% formic acid as the mobile phase. The ion transitions monitored in positive‐ion mode [M + H]+ of multiple‐reaction monitoring (MRM) were m/z 148.0 from m/z 584.0 for PPPA and m/z 194.0 from m/z 237.0 for the internal standard. The detector response was specific and linear for PPPA at concentrations within the range from 1 to 5,000 ng/mL. The intra−/inter‐day precision and accuracy of the method was acceptable by the criteria for assay validation. The matrix effects of PPPA ranged from 97.6 to 104.2% and from 93.3 to 105.3% in post‐preparative mouse and human plasma samples, respectively. PPPA was also stable under various processing and/or handling conditions. Finally, PPPA concentrations in the mouse plasma samples could be measured after intravenous, intraperitoneal, or oral administration of PPPA, suggesting that the assay is useful for pharmacokinetic studies on mice and applicable to human studies.
UPLC–MS/MS determination of flavokawain B, a novel anti‐tumor chemotherapeutic agent in rat plasma and its application to a pharmacokinetic study in rats
Authors: Yang Xueqin , Zan Tao , Yan Huiyu , Liu Baohua 
Published: September 2018

AbstractA sensitive, selective and rapid ultra‐performance liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of flavokawain B in rat plasma using myrislignan as an internal standard. Sample preparation was accomplished through a protein precipitation extraction process. Chromatographic resolution of flavokawain B and the IS was achieved on an Agilent XDB‐C18 column (2.1 × 100 mm, 1.8 μm) using a gradient mobile phase comprising 0.1% formic acid in water and acetonitrile delivered at a flow rate of 0.5 mL/min. Flavokawain B and the IS eluted at 3.27 and 1.96 min, respectively. The total chromatographic run time was 6.0 min. A linear response function was constructed in the concentration range 0.524–1048 ng/mL. Method validation was performed as per the US Food and Drug Administration guidelines and the results met the acceptance criteria. Intra‐ and inter‐day accuracy and precision were in the ranges of −14.3–13.2 and 3.4–11.8%, respectively. Flavokawain B was demonstrated to be stable under various stability conditions. This method has been applied to a pharmacokinetic study in rats.
New Dihydrostilbene Derivatives from Chloraea chrysantha
Authors: Tomassini Lamberto , Piovano Marisa , Ventrone Antonio , Pani Vincenzo , Frezza Claudio , Nicoletti Marcello 
Published: September 2018

AbstractThe study of the main components of the alcoholic extract obtained from Chloraea chrysantha Poepp. led to the isolation of two new dihydrostilbene derivatives together with the known gavilein (3). The new compounds have been assigned as 3‐methoxy‐5‐{2‐[3‐methoxy‐2‐(3‐methylbut‐2‐en‐1‐yl)phenyl]ethyl}phenol (1) and 1‐[2‐(3,5‐dimethoxyphenyl)ethyl]‐3‐methoxy‐2‐(3‐methylbut‐2‐en‐1‐yl)benzene (2). The presence of compounds 1–3 is perfectly in accordance with the current botanical classification of the genus.
Label‐Free Detection of Protein Tyrosine Phosphatase 1B (PTP1B) by Using a Rationally Designed Förster Resonance Energy Transfer (FRET) Probe
Authors: Durgannavar Trishaladevi , Kwon Se Jeong , Ghisaidoobe Amar B. T. , Rho Kyungmin , Kim Ju Hwan , Yoon Sun‐Young , Kang Hyo Jin , Chung Sang J. 
Published: September 2018

AbstractA highly selective detection method of native protein tyrosine phosphatase 1B (PTP1B) is described using a target specific probe equipped with 1‐naphthylamine (λex=330 nm, λem=445 nm). Irradiation of a mixture of PTP1B and Probe 1 with ultraviolet light of 280 nm (corresponding to PTP1B excitation maximum) resulted in significant fluorescence increase at 445 nm, following FRET characteristics. This phenomenon does not occur with other closely related phosphatases or cellular abundant alkaline phosphatase (APP). Probe 1, the most potent and selective probe, was found to competitively inhibit PTP1B (Ki≈42 nm), whereas APP inhibition was found to be in the low micromolar range. Furthermore, Probe 1 discriminates between PTP1B and several other phosphatases. Here, we report real‐time label‐free FRET detection of pure PTP1B as well as induced human PTP1B in Escherichia coli cell lysate. In contrast to 6,8‐difluoro‐4‐methylumbelliferyl phosphate (DiFMUP), a representative fluorescence turn‐on PTP substrate, our FRET probe successfully differentiated human cervical carcinoma cell lysate, SiHa, which has a high expression level of PTP1B, from PTP1B‐knockdown SiHa cell lysate (that is, siRNA was used for PTP1B knockdown).
Dopaminergic induction of human adipose‐derived mesenchymal stem cells is accompanied by transcriptional activation of autophagy
Authors: Hasani Sanaz , Boroujeni Mahdi Eskandarian , Aliaghaei Abbas , Baghai Kaveh , Rostami Amin 
Published: September 2018

AbstractNeural differentiation involves drastic morphological alterations, essentially performed by a cell‐homeostasis maintaining process known as autophagy. Here, we used the cocktail of choroid plexus epithelial cell‐conditioned medium (CPEC‐CM) and 15% knockout serum (KS) to induce human adipose‐derived mesenchymal stem cells (hASCs) into tyrosine hydroxylase (TH)‐positive neuron like cells. We showed that upon this induction, autophagy pathway was transcriptionally triggered. The expression levels of autophagy markers mTOR, BECN1, and MAP1LC3 were evidently changed throughout the dopaminergic (DAergic) differentiation of hASCs, highlighting the critical role of autophagy in this process at the level of transcription.
Ky‐2, a hybrid compound histone deacetylase inhibitor, regulated inflammatory response in LPS‐driven human macrophages
Authors: Kaneko Junya , Okinaga Toshinori , Ariyoshi Wataru , Hikiji Hisako , Fujii Seiko , Iwanaga Kenjiro , Tominaga Kazuhiro , Nishihara Tatsuji 
Published: September 2018

AbstractHistone deacetylase has attracted much attention as an epigenetic factor, and the modulation of histone and transcription factor acetylation status is important for regulating gene expression. Moreover, histone deacetylase inhibitors are involved in cellular growth and differentiation. In the present study, we examined the effects of Ky‐2, a hybrid‐compound HDAC inhibitor, on inflammatory reactions and the polarization of macrophages in vitro. Human monocyte‐like THP‐1 cells were polarized to macrophage‐like cells using phorbol 12‐myristate 13‐acetate, and then polarized to M1 macrophages with LPS. Ky‐2 inhibited HDAC2 expression and enhanced the acetylation of histone H3 in THP‐1 cells. It also downregulated the expression of the IL‐1β‐encoding gene and the LPS‐induced phosphorylation of p38 mitogen‐activated protein kinases in THP‐1 cells. Moreover, the expression of nod‐like receptor protein 3 and cleaved caspase‐1 p20 was downregulated in Ky‐2‐treated THP‐1 cells. In contrast, this agent upregulated the expression of IL‐1ra in LPS‐treated THP‐1 cells. These results indicate that Ky‐2‐treatment downregulates the expression of the inflammatory cytokine, IL‐1β, in LPS‐treated THP‐1 cells, suggesting that Ky‐2 might regulate M1 macrophage polarization through the suppression of inflammatory responses such as NLRP3 inflammasome activation.
Dentoalveolar fracture: A complication of extraction of upper left first molar
Authors: Tay Zhuo Wei , Zakaria Sarah Sabrina , Zamhari Ahmad Khairuddin , Lee Sie Wei 
Published: September 2018

Key Clinical MessageThe current trend of managing maxillary tuberosity fractures is traumatic and results in the loss of bone and teeth. Treatment options that chose to retain the fractured segments and teeth have been perceived to be unfavorable. This case report shows that maxillary tuberosity fractures can be treated conservatively.
Intrinsic Electrocatalytic Activity of Gold Nanoparticles Measured by Single Entity Electrochemistry
Authors: Peng Yue‐Yi , Guo Dan , Ma Wei , Long Yi‐Tao 
Published: September 2018

AbstractUnderstanding the real nature of the intrinsic electrocatalytic performance of the counter electrode is crucial for realizing high conversion efficiency of solar energy in photoelectric devices. However, owing to the average effects, a thorough insight into such electrocatalytic process remains challenging in ensemble measurements. Here, we realized the real‐time detection of electrocatalytic reduction of a single Au nanoparticle (NP) in sulfide/polysulfide redox electrolyte solution using single entity collision electrochemistry. Owing to the high‐sensitivity electrochemical measurement, size‐dependent electrocatalytic behaviors of polysulfide reduction were observed for single AuNP collision. Our approach allowed the electrocatalytic properties of AuNPs for polysulfide electrolyte reduction at the single NPs level to be quantified, and the turnover number as a function of particle size were further estimated. Our result has further pointed out the importance of NP size control in the electrocatalysis study.
Electrocatalytic Reduction of Hydrogen Peroxide by Pd−Ag Nanoparticles Based on the Collisional Approach
Authors: Li Mingzhi , Ge Zhiqiang , Zhang Shudong , He Peng , Gu Yaxiong , Qi Limin , Shao Yuanhua 
Published: September 2018

AbstractParticles collision onto a surface or an interface is a novel electrochemical approach, which can be used to investigate the behavior of single entities. Benefiting from advantages including single particle/single event resolution, label‐free detection and high sensitivity, this technique has been widely employed in the study of electrocatalytic amplification of detection signal by nanoparticles. Herein, we report the investigation of the collisional electrocatalytic behaviors of novel Pd−Ag hyperbranched nanoparticles through the observation of catalysis of hydrogen peroxide (H2O2) oxidation. The newly prepared Pd−Ag hyperbranched nanoparticles have been characterized by cyclic voltammetry and surface techniques. They can obviously reduce the overpotential of the reduction of H2O2 and show the high electrocatalytic activity. When the nanoparticles collide onto the electrode via the Brownian random motion, electrocatalytic reaction occurs and results in significant current increases, which could provide information about nanoparticles and electrochemical reactions. Furthermore, concentration and potential dependence are also investigated in detail, which confirms the reliability and universality of this methodology as an ultra‐sensitive probe. Based on these results, it is clearly shown that such platform is promising in further applications for biosensing and single nanoparticle analysis.
Synthetic Strategies and Structural Arrangements of Isoreticular Mixed‐Component Metal–Organic Frameworks
Authors: Bitzer Johannes , Kleist Wolfgang 
Published: September 2018

AbstractIn recent years, the synthesis of mixed‐metal and mixed‐linker metal–organic frameworks with multiple metals and/or linker molecules combined in one framework has become a growing field of interest. These mixed‐component or multivariate metal–organic framework materials provide the possibility to introduce multiple functionalities inside one framework. The interaction of guest molecules with different functionalities in the same material is a promising approach in the fields of gas storage, separation, catalysis and drug delivery. Furthermore, the combination of different components may lead to synergistic effects that cannot be achieved otherwise. These mixed‐component approaches open up new pathways to an even larger range of possible customizations in the field of metal–organic frameworks.
Synthesis of chiral salalen ligands and their in‐situ generated Cu‐complexes for asymmetric Henry reaction
Authors: Dixit Ashish , Kumar Pramod , Singh Surendra 
Published: September 2018

AbstractChiral salalen ligands derived from (S)‐proline and derivatives of salicyaldehydes were synthesized, and their in‐situ generated Cu (II) complexes were evaluated in the asymmetric Henry reaction. Salalen ligand of different substituents on the phenyl moiety showed remarkable effect on the enantioselectivity of nitro‐aldol product of 4‐nitrobenzaldehyde and nitromethane. Cu (II) complex generated in situ with (S)‐2‐(tert‐butyl)‐6‐((2‐(((2‐hydroxy‐3‐methylbenzylidene)amino)methyl)pyrrolidin‐1‐yl)methyl) phenol (10 mol%) and Cu (OAc)2.H2O (10 mol%), found to be better catalyst for nitro‐aldol reaction between 4‐nitrobenzaldehyde and nitromethane, gave corresponding product in 85% yield and 88% enantiomeric excess (ee) in isopropanol at 35°C after 40 hours. The catalyst also used for the Henry reaction with different substituted benzaldehydes and corresponding products were obtained in 22% to 99% yields with 66% to 92% ee. Henry reaction of 4‐nitrobenzaldehyde and prochiral nitroethane gave anti‐selective product (dr = 79/21; anti/syn) in a 91% yield with 80% ee.
Insights into Noncovalent Binding Obtained from Molecular Dynamics Simulations
Authors: Baz Jörg , Gebhardt Julia , Kraus Hamzeh , Markthaler Daniel , Hansen Niels 
Published: September 2018

AbstractThe key to nanoscale control of physical, chemical, and biological processes lies in well‐founded models of noncovalent binding. Atomistic simulations probe the free‐energy surface underlying molecular assembly processes in solution. Two examples of noncovalent binding studied by molecular dynamics simulations are discussed, the dimerization of a water‐soluble perylene bisimide derivative in aqueous solution with a focus on the influence of solvent composition on the aggregation strength and the binding of 1‐butanol to α‐cyclodextrin at infinite dilution with the focus on the determination of method‐independent binding free energies.
Lernzuwachs in Blended‐Learning Laborpraktika transparent machen – Feedbackfunktionen des LMS erweitern
Authors: Hedtrich Sebastian , Graulich Nicole 
Published: September 2018

AbstractBlended‐Learning‐Ansätze werden schon seit einiger Zeit in unterschiedlichen Lehr‐ und Lernformaten eingesetzt. Darunter auch Laborpraktika, zu denen sich die Studierenden online selbstständig vorbereiten können. Dabei werden Inhalte und Lernkontrollen über ein Lern‐Management‐System (LMS) angeboten. Bisher sind die Möglichkeiten der LMS noch unzureichend, um den Studierenden ein Feedback zu ihrem Lernzuwachs anzubieten. Mit einer neu entwickelten Software ist es uns erstmals möglich diesen Lernprozess zeitlich mitzuverfolgen. Die elektronische Lernkontrolle wird damit zu mehr als nur einem bloßen Ersatz für die Eingangskolloquien der Laborpraktika. Denn die Software nutzt die Daten der Lernkontrollen, um den Studierenden einen Einblick in ihren individuellen Lernzuwachs zu geben. Ein Feedback‐Text über Stärken und Schwächen kann schnell generiert und versendet werden.
Prolonged electromechanical delay as an early predictor of trastuzumab‐induced cardiotoxicity in patients undergoing treatment for breast cancer
Authors: Choe Jeong Cheon , Choi Jung Hyun , Choi Jong Hyun , Ahn Jinhee , Park Jin Sup , Lee Hye Won , Oh Jun‐Hyok , Lee Han Cheol , Cha Kwang Soo , Hong Taek Jong 
Published: September 2018

BackgroundWe aimed to investigate if left ventricular electromechanical delay (LVEMD) prolongation predicts trastuzumab‐induced cardiotoxicity (TIC) in breast cancer patients.HypothesisLVEMD prolongation on serial echocardiograms could be an indicator of subclinical TIC.MethodsWe included 237 breast cancer patients receiving trastuzumab chemotherapy, who underwent echocardiography at baseline and at 6 and 12 months after trastuzumab initiation. LVEMD was defined as the time from electrical activation to myocardial contraction. TIC was defined as left ventricular ejection fraction (LVEF) worsening to <55%, either as symptomatic decrease of ≥5% or asymptomatic decrease of ≥10%.ResultsDuring a mean follow‐up of 547 days, TIC occurred in 27 patients (11.4%). Changes in the time intervals from QRS onset on electrocardiography to the beginning and peak of transaortic flow on pulsed‐wave Doppler echocardiography (ie, ΔLVEMDi and ΔLVEMDp, respectively) were independent predictors of TIC. On receiver operating characteristic curve analysis, the optimal cutoff value for TIC prediction was 23 milliseconds for ΔLVEMDi (sensitivity, 0.85; specificity, 0.78; area under the curve [AUC], 0.882) and 21 milliseconds for ΔLVEMDp (sensitivity, 0.96; specificity, 0.68; AUC, 0.860). The C‐index for TIC prediction increased significantly after adding ΔLVEMDi and ΔLVEMDp to conventional models that included clinical variables, baseline LVEF, and changes in global longitudinal peak systolic strain. Similarly, adding ΔLVEMDi or ΔLVEMDp to conventional models provided significant improvement in discrimination capability for TIC prediction (integrated discrimination improvement and continuous net reclassification improvement index).ConclusionΔLVEMDi and ΔLVEMDp may serve as predictors of subclinical cardiac dysfunction in breast cancer patients receiving trastuzumab.
Vitamin D deficiency and electrocardiographic subclinical myocardial injury: Results from National Health and Nutrition Examination Survey‐III
Authors: Ahmad Muhammad I. , Chevli Parag A. , Li Yabing , Soliman Elsayed Z. 
Published: September 2018

BackgroundAssociation of cardiovascular disease (CVD) with nontraditional risk factors such as vitamin D deficiency has been examined previously. An investigation of the association of vitamin D with subclinical myocardial injury (SC‐MI) based on an electrocardiographic score is a simple, cost‐effective and innovative way to explore this relationship.HypothesisWe hypothesize that low vitamin D levels will be associated with prevalent SC‐MI independent of traditional CVD risk factors, lifestyle factors, and socioeconomic status.MethodsThis analysis included 6079 participants (58.3 ± 13.1 years; 54.1% women) without CVD from the third National Health and Nutrition Examination Survey. A multivariable logistic regression model was used to examine the association between vitamin D categories (<20, 20‐29, and >30 ng/mL (reference) and cardiac injury score.ResultsThere was an incremental increase in the prevalence of SC‐MI across vitamin D categories with the highest prevalence in <20 ng/mL, followed by 20 to 29 ng/mL and then >30 ng/mL (trend P‐value <0.0001). There was a statistically significant association between vitamin D deficiency (<20 ng/mL) and SC‐MI (odds ratio [OR] (95% confidence interval [CI]): 1.27 (1.04‐1.55), P = 0.04). This association was stronger in men than women (OR (95% CI): 1.74 (1.32‐2.30) vs 0.94 (0.70‐1.25) respectively; interaction P‐value 0.002).ConclusionsVitamin D deficiency is associated with SC‐MI, especially in men. These findings may further highlight the role of nontraditional risk factors in the development of CVD. The value of vitamin D supplementation in the prevention of myocardial ischemia and injury may warrant investigation.