bluuebunny/crossref_metadata_2025 huggingface dataset:
Enantioselective Visible‐Light‐Mediated Formation of 3‐Cyclopropylquinolones by Triplet‐Sensitized Deracemization
Authors: Tröster Andreas , Bauer Andreas , Jandl Christian , Bach Thorsten
Published: January 2019

3‐Allyl‐substituted quinolones undergo a triplet‐sensitized di‐π‐methane rearrangement reaction to the corresponding 3‐cyclopropylquinolones upon irradiation with visible light (λ=420 nm). A chiral hydrogen‐bonding sensitizer (10 mol %) was shown to promote the reaction enantioselectively (88–96 % yield, 32–55 % ee). Surprisingly, it was found that the enantiodifferentiation does not occur at the state of initial product formation but that it is the result of a deracemization event. The individual parameters that control the distribution of enantiomers in the photostationary state have been identified.
Enantioselektiver Aufbau von α‐chiralen Silanen durch nickelkatalysierte C(sp3)‐C(sp3)‐Kreuzkupplung
Authors: Yi Hong , Mao Wenbin , Oestreich Martin
Published: January 2019

Es wird über eine enantioselektive C(sp3)‐C(sp3)‐Kreuzkupplung von racemischen α‐silylierten Alkyliodiden und Alkylzinkreagenzien berichtet. Die Reaktion wird von NiCl2/(S,S)‐Bn‐Pybox katalysiert und erbringt α‐chirale Silane mit hoher Enantiokontrolle. Das Katalysatorsystem ist nicht in der Lage, die Kreuzkupplung des entsprechenden Kohlenstoffanalogons zu vermitteln, was den stabilisierenden Effekt der Silylgruppe auf die Alkylradikalzwischenstufe untermauert (α‐Siliciumeffekt). Beide Kupplungspartner können, müssen aber nicht, funktionalisiert sein und damit werden selbst α‐chirale Silane ohne funktionelle Gruppe in unmittelbarer Nähe zum asymmetrisch substituierten Kohlenstoffatom zugänglich. Dies unterscheidet das neue Verfahren von den etablierten Methoden zur Synthese von α‐chiralen Silanen.
Synthesis and Characterization of a Pentiptycene‐Derived Dual Oligoparaphenylene Nanohoop
Authors: Xu Wei , Yang Xiao‐Di , Fan Xiang‐Bing , Wang Xin , Tung Chen‐Ho , Wu Li‐Zhu , Cong Huan
Published: January 2019

Structural designs combining oligoparaphenylene‐derived nanohoops with other functional organic building blocks should lead to novel molecular architectures with intriguing properties. Herein, we describe the synthesis of a pentiptycene‐derived chiral dual nanohoop molecule with key steps including ring expansion through dianthracene cycloreversion and transannular [4+2] cycloaddition across a 64‐membered macrocycle. The crystal structure of the nanohoop molecule displays an ordered packing pattern with long‐range channels in the solid state. Furthermore, nonracemizable enantiomers of the nanohoop were obtained through resolution and exhibited promising chiroptical properties.
Direct Observation of Aryl Gold(I) Carbenes that Undergo Cyclopropanation, C−H Insertion, and Dimerization Reactions
Authors: García‐Morales Cristina , Pei Xiao‐Li , Sarria Toro Juan M. , Echavarren Antonio M.
Published: January 2019

Mesityl gold(I) carbenes lacking heteroatom stabilization or shielding ancillary ligands have been generated and spectroscopically characterized from chloro(mesityl)methylgold(I) carbenoids bearing JohnPhos‐type ligands by chloride abstraction with GaCl3. The aryl carbenes react with PPh3 and alkenes to give stable phosphonium ylides and cyclopropanes, respectively. Oxidation with pyridine N‐oxide and intermolecular C−H insertion to cyclohexane have also been observed. In the absence of nucleophiles, a bimolecular reaction, similar to that observed for other metal carbenes, leads to a symmetrical alkene.
An Unexpected Role of Hyaluronic Acid in Trafficking siRNA Across the Cellular Barrier: The First Biomimetic, Anionic, Non‐Viral Transfection Method
Authors: Paidikondala Maruthibabu , Rangasami Vignesh Kumar , Nawale Ganesh N. , Casalini Tommaso , Perale Giuseppe , Kadekar Sandeep , Mohanty Gaurav , Salminen Turkka , Oommen Oommen P. , Varghese Oommen P.
Published: January 2019

Circulating nucleic acids, such as short interfering RNA (siRNA), regulate many biological processes; however, the mechanism by which these molecules enter the cell is poorly understood. The role of extracellular‐matrix‐derived polymers in binding siRNAs and trafficking them across the plasma membrane is reported. Thermal melting, dynamic light scattering, scanning electron microscopy, and computational analysis indicate that hyaluronic acid can stabilize siRNA via hydrogen bonding and Van der Waals interactions. This stabilization facilitated HA size‐ and concentration‐dependent gene silencing in a CD44‐positive human osteosarcoma cell line (MG‐63) and in human mesenchymal stromal cells (hMSCs). This native HA‐based siRNA transfection represents the first report on an anionic, non‐viral delivery method that resulted in approximately 60 % gene knockdown in both cell types tested, which correlated with a reduction in translation levels.
Chiral Zinc(II)‐Catalyzed Enantioselective Tandem α‐Alkenyl Addition/Proton Shift Reaction of Silyl Enol Ethers with Ketimines
Authors: Kang Tengfei , Cao Weidi , Hou Liuzhen , Tang Qiong , Zou Sijia , Liu Xiaohua , Feng Xiaoming
Published: January 2019

A new catalytic asymmetric tandem α‐alkenyl addition/proton shift reaction of silyl enol ethers with ketimines was serendipitously discovered in the presence of chiral N,N′‐dioxide/ZnII complexes. The proton shift preferentially proceeded instead of a silyl shift after α‐alkenyl addition of silyl enol ether to the ketimine. A wide range of β‐amino silyl enol ethers were synthesized in high yields with good to excellent ee values. Control experiments suggest that the Mukaiyama–Mannich reaction and tandem α‐alkenyl addition/proton shift reaction are competitive reactions in the current catalytic system. The obtained β‐amino silyl enol ethers were easily transformed into β‐fluoroamines containing two vicinal tetrasubstituted carbon centers.
Halogen‐Dependent Surface Confinement Governs Selective Alkane Functionalization to Olefins
Authors: Zichittella Guido , Scharfe Matthias , Puértolas Begoña , Paunović Vladimir , Hemberger Patrick , Bodi Andras , Szentmiklósi László , López Núria , Pérez‐Ramírez Javier
Published: January 2019

The product distribution in direct alkane functionalization by oxyhalogenation strongly depends on the halogen of choice. We demonstrate that the superior selectivity to olefins over an iron phosphate catalyst in oxychlorination is the consequence of a surface‐confined reaction. By contrast, in oxybromination alkane activation follows a gas‐phase radical‐chain mechanism and yields a mixture of alkyl bromide, cracking, and combustion products. Surface‐coverage analysis of the catalyst and identification of gas‐phase radicals in operando mode are correlated to the catalytic performance by a multi‐technique approach, which combines kinetic studies with advanced characterization techniques such as prompt‐gamma activation analysis and photoelectron photoion coincidence spectroscopy. Rationalization of gas‐phase and surface contributions by density functional theory reveals that the molecular level effects of chlorine are pivotal in determining the stark selectivity differences. These results provide strategies for unraveling detailed mechanisms within complex reaction networks.
Study on single and binary catalytic systems of pyridine‐imine catalysts based on nickel and iron in synthesis of reactor blends and low‐density polyethylene nanocomposites
Authors: Mogheiseh Mohsen , Zohuri Gholam Hossein , Khoshsefat Mostafa
Published: January 2019

In the presence of modified methylaluminoxane as cocatalyst, the behavior of a binary catalytic system based on pyridine‐imine nickel (N) and iron (F) catalysts was evaluated in order to reach a proper mixture of polyethylene (PE). A computational study along with kinetic profile suggested that the catalyst F with higher electron affinity (A) and electrophilicity (ω) in the methyl cationic active center and stronger interaction with the monomer led to high integrated monomer consumption and higher activity. In addition, the samples produced by the mixture of catalysts showed a higher value of [19.4 × 104 g (PE) mol (Fe+Ni)−1 h−1)], melting point (127.8 °C), and crystallinity extent (41.29%) than the samples produced by the single catalysts. The addition of multiwalled carbon nanotubes (MWCNT) into the polymerization media reduced the activity of catalysts [from 7.50 × 104 to 0.66 × 104 g (PE) mol (Fe+Ni)−1 h−1] and the thermal properties of the low‐density polyethylene nanocomposite samples. However, the sample containing 2.33% MWCNT20‐30 improved the total thermal stability of the neat polyethylene blend up to 400 °C. Scanning electron microscope images of the samples demonstrated irregular to virtually uniform morphologies were obtained through the in situ and solution‐mixing techniques. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47376.
Oligoamide Foldamers as Helical Chloride Receptors—the Influence of Electron‐Withdrawing Substituents on Anion‐Binding Interactions
Authors: Helttunen Kaisa , Annala Riia , Suhonen Aku , Iloniemi Juho , Kalenius Elina , Aragay Gemma , Ballester Pablo , Tuononen Heikki M. , Nissinen Maija
Published: January 2019

The anion‐binding properties of three closely related oligoamide foldamers were studied using NMR spectroscopy, isothermal titration calorimetry and mass spectrometry, as well as DFT calculations. The 1H NMR spectra of the foldamers in [D6]acetone solution revealed partial preorganization by intramolecular hydrogen bonding, which creates a suitable cavity for anion binding. The limited size of the cavity, however, enabled efficient binding by the inner amide protons only for the chloride anion resulting in the formation of a thermodynamically stable 1:1 complex. All 1:1 chloride complexes displayed a significant favourable contribution of the entropy term. Most likely, this is due to the release of ordered solvent molecules solvating the free foldamer and the anion to the bulk solution upon complex formation. The introduction of electron‐withdrawing substituents in foldamers 2 and 3 had only a slight effect on the thermodynamic constants for chloride binding compared to the parent receptor. Remarkably, the binding of chloride to foldamer 3 not only produced the expected 1:1 complex but also open aggregates with 1:2 (host:anion) stoichiometry.
Squaraine Dyes: Interaction with Bovine Serum Albumin to Investigate Supramolecular Adducts with Aggregation‐Induced Emission (AIE) Properties
Authors: Barbero Nadia , Butnarasu Cosmin , Visentin Sonja , Barolo Claudia
Published: January 2019

Bovine serum albumin (BSA)–squaraine supramolecular adducts with aggregation‐induced emission (AIE) properties were prepared and characterized by spectroscopic methods. While squaraine dyes showed a very low fluorescence quantum yield in water, a great enhancement in the fluorescence of the aggregated BSA adducts was achieved due to the abnormal aggregation‐induced emission properties of squaraines. The adducts formation was studied from a kinetic point of view showing unexpected structure–properties relationships.
Estimation of log‐odds ratio from group testing data using Firth correction
Authors: Roy Surupa , Banerjee Tathagata
Published: January 2019

We consider the estimation of the prevalence of a rare disease, and the log‐odds ratio for two specified groups of individuals from group testing data. For a low‐prevalence disease, the maximum likelihood estimate of the log‐odds ratio is severely biased. However, Firth correction to the score function leads to a considerable improvement of the estimator. Also, for a low‐prevalence disease, if the diagnostic test is imperfect, the group testing is found to yield more precise estimate of the log‐odds ratio than the individual testing.
Control of IgG glycosylation by in situ and real‐time estimation of specific growth rate of CHO cells cultured in bioreactor
Authors: Li Meng‐Yao , Ebel Bruno , Blanchard Fabrice , Paris Cédric , Guedon Emmanuel , Marc Annie
Published: January 2019

The cell‐specific growth rate (µ) is a critical process parameter for antibody production processes performed by animal cell cultures, as it describes the cell growth and reflects the cell physiological state. When there are changes in these parameters, which are indicated by variations ofµ, the synthesis and the quality of antibodies are often affected. Therefore, it is essential to monitor and control the variations ofµto assure the antibody production and achieve high product quality. In this study, a novel approach for on‐line estimation ofµwas developed based on the process analytical technology initiative by using an in situ dielectric spectroscopy. Critical moments, such as significantµdecreases, were successfully detected by this method, in association with changes in cell physiology as well as with an accumulation of nonglycosylated antibodies. Thus, this method was used to perform medium renewals at the appropriate time points, maintaining the values ofµclose to its maximum. Using this method, we demonstrated that the physiological state of cells remained stable, the quantity and the glycosylation quality of antibodies were assured at the same time, leading to better process performances compared with the reference feed‐harvest cell cultures carried out by using off‐line nutrient measurements.
Combining orthogonal CRISPR and CRISPRi systems for genome engineering and metabolic pathway modulation in Escherichia coli
Authors: Sung Li‐Yu , Wu Meng‐Ying , Lin Mei‐Wei , Hsu Mu‐Nung , Truong Vu Anh , Shen Chih‐Che , Tu Yi , Hwang Kuen‐Yuan , Tu An‐Pang , Chang Yu‐Han , Hu Yu‐Chen
Published: January 2019

CRISPR utilizing Cas9 from Streptococcus pyogenes (SpCas9) and CRISPR interference (CRISPRi) employing catalytically inactive SpCas9 (SpdCas9) have gained popularity for
Escherichia coli engineering. To integrate the SpdCas9‐based CRISPRi module using CRISPR while avoiding mutual interference between SpCas9/SpdCas9 and their cognate single‐guide RNA (sgRNA), this study aimed at exploring an alternative Cas nuclease orthogonal to SpCas9. We compared several Cas9 variants from different microorganisms such as
Staphylococcus aureus (SaCas9) and
Streptococcus thermophilius CRISPR1 (St1Cas9) as well as Cas12a derived from
Francisella novicida (FnCas12a). At the commonly used
E. coli model genes 
LacZ, we found that SaCas9 and St1Cas9 induced DNA cleavage more effectively than FnCas12a. Both St1Cas9 and SaCas9 were orthogonal to SpCas9 and the induced DNA cleavage promoted the integration of heterologous DNA of up to 10 kb, at which size St1Cas9 was superior to SaCas9 in recombination frequency/accuracy. We harnessed the St1Cas9 system to integrate SpdCas9 and sgRNA arrays for constitutive knockdown of three genes, knock‐in
pyc and knockout
adhE, without compromising the CRISPRi knockdown efficiency. The combination of orthogonal CRISPR/CRISPRi for metabolic engineering enhanced succinate production while inhibiting byproduct formation and may pave a new avenue to
E. coli engineering.
Three‐dimensional spherical gelatin bubble‐based scaffold improves the myotube formation of H9c2 myoblasts
Authors: Mei Chieh , Chao Chih‐Wei , Lin Che‐Wei , Li Shing Tak , Wu Kuan‐Han , Yang Kai‐Chiang , Yu Jiashing
Published: January 2019

Microenvironmental factors including physical and chemical cues can regulate stem cells as well as terminally differentiated cells to modulate their biological function and differentiation. However, one of the physical cues, the substrate's dimensionality, has not been studied extensively. In this study, the ﬂow‐focusing method with a microﬂuidic device was used to generate gelatin bubbles to fabricate highly ordered three‐dimensional (3D) scaffolds. Rat H9c2 myoblasts were seeded into the 3D gelatin bubble‐based scaffolds and compared to those grown on 2D gelatin‐coating substrates to demonstrate the influences of spatial cues on cell behaviors. Relative to cells on the 2D substrates, the H9c2 myoblasts were featured by a good survival and normal mitochondrial activity but slower cell proliferation within the 3D scaffolds. The cortical actin filaments of H9c2 cells were localized close to the cell membrane when cultured on the 2D substrates, while the F‐actins distributed uniformly and occupied most of the cell cytoplasm within the 3D scaffolds. H9c2 myoblasts fused as multinuclear myotubes within the 3D scaffolds without any induction but cells cultured on the 2D substrates had a relatively lower fusion index even differentiation medium was provided. Although there was no difference in actin α 1 and myosin heavy chain 1, H9c2 cells had a higher myogenin messenger RNA level in the 3D scaffolds than those of on the 2D substrates. This study reveals that the dimensionality influences differentiation and fusion of myoblasts.
Distinct timescales of RNA regulators enable the construction of a genetic pulse generator
Authors: Westbrook Alexandra , Tang Xun , Marshall Ryan , Maxwell Colin S. , Chappell James , Agrawal Deepak K. , Dunlop Mary J. , Noireaux Vincent , Beisel Chase L. , Lucks Julius , Franco Elisa
Published: January 2019

To build complex genetic networks with predictable behaviors, synthetic biologists use libraries of modular parts that can be characterized in isolation and assembled together to create programmable higher‐order functions. Characterization experiments and computational models for gene regulatory parts operating in isolation are routinely used to predict the dynamics of interconnected parts and guide the construction of new synthetic devices. Here, we individually characterize two modes of RNA‐based transcriptional regulation, using small transcription activating RNAs (STARs) and clustered regularly interspaced short palindromic repeats interference (CRISPRi), and show how their distinct regulatory timescales can be used to engineer a composed feedforward loop that creates a pulse of gene expression. We use a cell‐free transcription‐translation system (TXTL) to rapidly characterize the system, and we apply Bayesian inference to extract kinetic parameters for an ordinary differential equation‐based mechanistic model. We then demonstrate in simulation and verify with TXTL experiments that the simultaneous regulation of a single gene target with STARs and CRISPRi leads to a pulse of gene expression. Our results suggest the modularity of the two regulators in an integrated genetic circuit, and we anticipate that construction and modeling frameworks that can leverage this modularity will become increasingly important as synthetic circuits increase in complexity.
In vitro vascularized liver and tumor tissue microenvironments on a chip for dynamic determination of nanoparticle transport and toxicity
Authors: Ozkan Alican , Ghousifam Neda , Hoopes Paul Jack , Yankeelov Thomas Edward , Rylander Marissa Nichole
Published: January 2019

This paper presents the development of a vascularized breast tumor and healthy or tumorigenic liver microenvironments‐on‐a‐chip connected in series. This is the first description of a vascularized multi tissue‐on‐a‐chip microenvironment for modeling cancerous breast and cancerous/healthy liver microenvironments, to allow for the study of dynamic and spatial transport of particles. This device enables the dynamic determination of vessel permeability, the measurement of drug and nanoparticle transport, and the assessment of the associated efficacy and toxicity to the liver. The platform is utilized to determine the effect of particle size on the spatiotemporal diffusion of particles through each microenvironment, both independently and in response to the circulation of particles in varying sequences of microenvironments. The results show that when breast cancer cells were cultured in the microenvironments they had a 2.62‐fold higher vessel porosity relative to vessels within healthy liver microenvironments. Hence, the permeability of the tumor microenvironment increased by 2.35‐ and 2.77‐fold compared with a healthy liver for small and large particles, respectively. The extracellular matrix accumulation rate of larger particles was 2.57‐fold lower than smaller particles in a healthy liver. However, the accumulation rate was 5.57‐fold greater in the breast tumor microenvironment. These results are in agreement with comparable in vivo studies. Ultimately, the platform could be utilized to determine the impact of the tissue or tumor microenvironment, or drug and nanoparticle properties, on transport, efficacy, selectivity, and toxicity in a dynamic, and high‐throughput manner for use in treatment optimization.
Analysis of Golgi pH in Chinese hamster ovary cells using ratiometric pH‐sensitive fluorescent proteins
Authors: Lee Jong Hyun , Kim Jihoon , Park Jong‐Ho , Heo Won Do , Lee Gyun Min
Published: January 2019

Acidic Golgi pH plays an important role in protein glycosylation, one of the critical quality attributes of therapeutic proteins. To determine the intracellular Golgi pH during culture, stable Chinese hamster ovary (CHO) cell clones expressing pHluorin2, a ratiometric pH‐sensitive fluorescent protein (FP), in the cis‐ and trans‐Golgi, were constructed by fusing pHluorin2 with specific targeting proteins, acetylglucosaminyltransferase, and a galactosyltransferase, respectively. Stable CHO cell clones expressing pHluorin2 in the cytoplasm were also constructed. The subcellular localization of FPs was confirmed by immunofluorescence analysis. Live‐cell imaging revealed that the intracellular pH (pHi) of clones expressing the ratiometric pH‐sensitive FPs converged to a specific pH range (cis‐Golgi: 6.4–6.5; trans‐Golgi: 5.9–6.0; and cytoplasm: 7.1–7.2). The pHi was successfully evaluated in various culture conditions. Although culture pH was maintained at 7.2 in a bioreactor, the Golgi pH increased with culture time. Elevated ammonia concentration and osmolality were partially responsible for the increased Golgi pH during bioreactor cultures. Taken together, the application of ratiometric pH‐sensitive FPs in monitoring the Golgi pH of CHO cells during culture provides a new perspective to improve protein glycosylation through pHi control.
Continuous integrated antibody precipitation with two‐stage tangential flow microfiltration enables constant mass flow
Authors: Burgstaller Daniel , Jungbauer Alois , Satzer Peter
Published: January 2019

Continuous precipitation is a new unit operation for the continuous capture of antibodies. The capture step is based on continuous precipitation with PEG6000 and Zn++ in a tubular reactor integrated with a two‐stage continuous tangential flow filtration unit. The precipitate cannot be separated with centrifugation, because a highly compressed sediment results in poor resolubilization. We developed a new two‐stage tangential flow microfiltration method, where part of the concentrated retentate of the first stage was directly fed to the second stage, together with the wash buffer. Thus, the precipitate was concentrated and washed in a continuous process. We obtained 97% antibody purity, a 95% process yield during continuous operation, and a fivefold reduction in pre‐existing high‐molecular‐weight impurities. For other unit operations, surge tanks are often required, due to interruptions in the product mass flow out of the unit operation (e.g., the bind/elute mode in periodic counter‐current chromatography). Our setup required no surge tanks; thus, it provided a truly continuous antibody capture operation with uninterrupted product mass flow. Continuous virus inactivation and other flow‐through unit operations can be readily integrated downstream of the capture step to create truly continuous, integrated, downstream antibody processing without the need for hold tanks.
Effect of precise control of flux ratio between the glycolytic pathways on mevalonate production in Escherichia coli
Authors: Kamata Kentaro , Toya Yoshihiro , Shimizu Hiroshi
Published: January 2019

Mevalonate is a useful metabolite synthesized from three molecules of acetyl‐CoA, consuming two molecules of NADPH. Escherichia coli (
E. coli) catabolizes glucose to acetyl‐CoA via several routes, such as the Embden–Meyerhof–Parnas (EMP) and the oxidative pentose phosphate (oxPP) pathways. Although the oxPP pathway supplies NADPH, it is disadvantageous in terms of acetyl‐CoA supply, compared with the EMP pathway. In this study, the optimal flux ratio between the EMP and oxPP pathways on the mevalonate yield was investigated. Expression level of
pgi was controlled by isopropyl β‐D‐1‐thiogalactopyranoside (IPTG) inducible promoter in an engineered mevalonate‐producing
E. coli strain. The relationship between the flux ratio and mevalonate yield was evaluated by changing the flux ratio by varying IPTG concentration. At the stationary phase, the mevalonate yield was maximum at an EMP flux of 39.7%, and was increased by 25% compared with that with no flux control (EMP flux of 70.4%). The optimal flux ratio was consistent with the theoretical value based on the mass balance of NADPH. The flux ratio between EMP and oxPP pathways affects the synthesis fluxes of mevalonate and acetate from acetyl‐CoA. Fine tuning of the flux ratio would be necessary to achieve an optimized production of metabolites that require NADPH.
Virtual Screening and Biochemical Evaluation to Identify the Allosteric Inhibitors of Dual Specificity Phosphatase 1
Authors: Park Hwangseo , Kim Myeongbin , Park Tae Hyun , Jeon Tae Jin , Chun Ha‐Jung , Eon Ryu Seong
Published: January 2019

Although a wealth of persuasive evidence was provided for the involvement of dual specificity phosphatase 1 (DUSP1) in cancers, depression, and hepatitis C virus replication, small‐molecule inhibitors have been reported rarely. Because most competitive phosphatase inhibitors are disadvantageous in terms of pharmacological properties due to the possession of highly polar groups, we aim in this work to identify the allosteric DUSP1 inhibitors through the structure‐based virtual screening. Using the modified protein‐ligand binding energy function involving an accurate molecular dehydration term, we identify six allosteric DUSP1 inhibitors that impair the enzymatic activity at low‐micromolar level. Consistent with the kinetic analysis on the inhibitory mechanism, docking simulation results indicate that the newly discovered inhibitors would bind in the peripheral binding pocket of DUSP1 in preference to the active site. Besides the micromolar‐level biochemical potency, the allosteric DUSP1 inhibitors found in this work may be meritorious over the competitive ones because of the lack of the reactive moiety to mimic the substrate phosphate group. Hence, they are anticipated to serve as a good starting point for the development of new therapeutics against cancers and neurological diseases.
Altered functional connectivity in binge eating disorder and bulimia nervosa: A resting‐state fMRI study
Authors: Stopyra Marion A. , Simon Joe J. , Skunde Mandy , Walther Stephan , Bendszus Martin , Herzog Wolfgang , Friederich Hans‐Christoph
Published: January 2019

Introduction

The etiology of bulimic‐type eating (BTE) disorders such as binge eating disorder (BED) and bulimia nervosa (BN) is still largely unknown. Brain networks subserving the processing of rewards, emotions, and cognitive control seem to play a crucial role in the development and maintenance of eating disorders. Therefore, further investigations into the neurobiological underpinnings are needed to discern abnormal connectivity patterns in BTE disorders.

Methods

The present study aimed to investigate functional as well as seed‐based connectivity within well‐defined brain networks. Twenty‐seven individuals with BED, 29 individuals with BN, 28 overweight, and 30 normal‐weight control participants matched by age, gender, and education underwent resting‐state functional magnetic resonance imaging. Functional connectivity was assessed by spatial group independent component analysis and a seed‐based correlation approach by examining the default mode network (DMN), salience network (SN), and executive network (EN).

Results

Group comparisons revealed that BTE disorder patients exhibit aberrant functional connectivity in the dorsal anterior cingulate cortex (dACC) within the SN, as well as in the medial prefrontal cortex within the DMN. Furthermore, BED and BN groups differed from each other in functional connectivity within each network. Seed‐based correlational analysis revealed stronger synchronous dACC‐retrosplenial cortex activity in the BN group.

Conclusion

Our findings demonstrate abnormalities in brain networks involved in salience attribution, self‐referential processing, and cognitive control in bulimic‐type eating disorders. Together with our observation of functional connectivity differences between BED and BN, this study offers a differentiated account of both similarities and differences regarding brain connectivity in BED and BN.
Fecal Fusobacterium nucleatum for the diagnosis of colorectal tumor: A systematic review and meta‐analysis
Authors: Zhang Xinyu , Zhu Xiaoqiang , Cao Yingying , Fang Jing‐Yuan , Hong Jie , Chen Haoyan
Published: January 2019

The fecal Fusobacterium nucleatum has been reported as a potential noninvasive biomarker for colorectal tumor in several studies, but its exact diagnostic accuracy was ambiguous due to the wide range of sensitivity and specificity. To assess the diagnostic accuracy of fecal F. nucleatum for colorectal tumor, we searched electronic databases including PubMed, Cochrane Library, Embase, and Web of Science, without any date and language restrictions. Two reviewers independently extracted data and appraised study quality with Quality Assessment of Diagnostic Accuracy Studies. We included ten studies comprising 13 cohorts for colorectal cancer (CRC) and seven cohorts for colorectal adenoma (CRA). A total of 1450 patients and 1421 controls for CRC and 656 patients and 827 controls for CRA were included. The pooled sensitivity and specificity of fecal F. nucleatum for CRC were 71% (95% CI, 61%‐79%) and 76% (95% CI, 66%‐84%), with the area under the receiver‐operating characteristics (AUC) curve of 0.80 (95% CI, 0.76‐0.83). The pooled sensitivity and specificity of fecal F. nucleatum for CRA were 36% (95% CI, 27%‐46%) and 73% (95% CI, 65%‐79%), with an AUC of 0.60 (95% CI, 0.56‐0.65). Substantial heterogeneity among studies existed, which was partly caused by DNA extraction kits, regions of study, sample size, and demographic characteristics of participants. Fecal F. nucleatum was valuable for the diagnosis of CRC although it performed below expectation. For CRA, the specificity of fecal F. nucleatum indicated the possibility of noninvasive screening. Subgroup analyses for adenoma were incomplete due to lack of data. Heterogeneity limited the credibility of the study.
CD44 standard isoform is involved in maintenance of cancer stem cells of a hepatocellular carcinoma cell line
Authors: Asai Ryoma , Tsuchiya Hiroyuki , Amisaki Masataka , Makimoto Kazuki , Takenaga Ai , Sakabe Tomohiko , Hoi Shotaro , Koyama Shigemi , Shiota Goshi
Published: January 2019

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide. Cancer stem cells (CSCs) have attracted attention as a novel therapeutic target for cancer because they play important roles in the development and aggravation of cancer. CD44 is expressed as a standard isoform (CD44s) and several variant isoforms. CD44v is a major isoform expressed on CSCs of a variety of tumors and has been extensively studied. However, HCC tissues dominantly express CD44s, whose function in CSCs remains unclear. In the present study, we investigated the roles of CD44s in CSCs of HCC. Knock‐out of the CD44 gene in HuH7 HCC cells on which only CD44s is expressed resulted in decreased spheroid formation and increased drug sensitivity. The expression of CSC marker genes, including CD133 and EpCAM, was significantly downregulated in the spheroids of CD44‐deficient cells compared with those in the spheroids of HuH7 cells. In addition, CD44 deficiency impaired antioxidant capacity, concomitant with downregulation of glutathione peroxidase 1 (GPX1) and thioredoxin. Because GPX1 uses the reduced form of glutathione (GSH) to regenerate oxidized cellular components, GSH levels were significantly increased in the CD44‐deficient cells. We also found that NOTCH3 and its target genes were downregulated in the spheroids of CD44‐deficient cells. NOTCH3 expression in HCC tissues was significantly increased compared with that in adjacent nontumor liver tissues and was correlated with CD44 expression. These results suggest that CD44s is involved in maintenance of CSCs in a HCC cell line, possibly through the NOTCH3 signaling pathway.
BRCA1 affects the resistance and stemness of SKOV3‐derived ovarian cancer stem cells by regulating autophagy
Authors: You Yue , Bi Fang‐Fang , Jiang Ying , Xu Ye‐Tao , An Yuan‐Yuan , Li Da , Yang Qing
Published: January 2019

Breast cancer 1 (BRCA1) and autophagy both play a significant role in drug resistance. However, little is known about the dynamic cross talk between BRCA1 and autophagy in the regulation of drug sensitivity. Here, we investigated the drug resistance‐associated regulation of BRCA1 in epithelial ovarian cancer stem cells (EOCSCs). The results indicated that BRCA1 could regulate drug resistance in EOCSCs. Autophagy played a significant role in the stemness maintenance and was a key mechanism underlying the survival against chemotherapy in EOCSCs. Further investigation found that BRCA1 could regulate drug resistance of EOCSCs through autophagy. Meanwhile, changes in the level of autophagy provided feedback regarding the expression of BRCA1. Inhibition of autophagy activity could effectively reduce the resistance of EOCSCs caused by BRCA1. In addition, BRCA1 was able to regulate cellular apoptosis and cell cycle progression under the action of cisplatin through autophagy, indirectly affecting the drug sensitivity of EOCSCs. The present results highlight a novel relationship between BRCA1 and autophagy, which may provide insight into the etiology of BRCA1‐associated ovarian cancer, and improve our understanding of resistance mechanisms in ovarian cancer.
Identification and Quantification of (t)RNA Modifications in Pseudomonas aeruginosa by Liquid Chromatography–Tandem Mass Spectrometry
Authors: Grobe Svenja , Doberenz Sebastian , Ferreira Kevin , Krueger Jonas , Brönstrup Mark , Kaever Volkhard , Häussler Susanne
Published: January 2019

Transfer RNA (tRNA) modifications impact the structure and function of tRNAs, thus affecting the efficiency and fidelity of translation. In the opportunistic pathogen Pseudomonas aeruginosa translational regulation plays an important but less defined role in adaptation to changing environments. In this study, we have explored tRNA modifications in P. aeruginosa through LC‐MS/MS approaches. Neutral loss scanning (NLS) demonstrated the potential to identify previously unknown modifications, whereas multiple reaction monitoring (MRM) was able to detect modifications with high specificity and sensitivity. In this study, the MRM‐based external calibration method allowed for quantification of the four canonical and 32 modified ribonucleosides, out of which 21 tRNA modifications were quantified in the total tRNA pool of P. aeruginosa PA14. We also purified the single tRNA isoacceptors tRNA‐ArgUCU, tRNA‐LeuCAA, and tRNA‐TrpCCA and determined their specific modification patterns, both qualitatively and quantitatively. Deeper insights into the nature and dynamics of tRNA modifications in P. aeruginosa should pave the way for further studies on post‐transcriptional gene regulation as a relatively unexplored molecular mechanism of controlling bacterial pathogenicity and mode of growth.
3‐Hydroxyisobutyryl‐CoA hydrolase deficiency in an Iranian child with novel HIBCH compound heterozygous mutations
Authors: Karimzadeh Parvaneh , Saberi Mohammad , Sheidaee Kobra , Nourbakhsh Mitra , Keramatipour Mohammad
Published: January 2019

Key Clinical Message

We report a patient presenting with developmental delay, Leigh‐like abnormalities on MRI and elevated 3‐hydroxyisovaleric acid levels. Upon whole‐exome sequencing, he was diagnosed with 3‐hydroxyisobutyryl‐CoA hydrolase (HIBCH) deficiency, and hence subjected to specific dietary treatment. HIBCH deficiency should be considered in the differential diagnosis of Leigh‐like disease and/or organic aciduria.
Transient Dipnictyl Analogues of Acrylamides, R−E=E′−CONR2, and a Related Diphosphadigalletane from Na[OCP] and (R2N)2ECl (E, E′=P, As, Ga)
Authors: Borger Jaap E. , Le Corre Grégoire , Mei Yanbo , Suter Riccardo , Schrader Erik , Grützmacher Hansjörg
Published: January 2019

The reaction of Na[OCP] with (R2N)2ECl (E=P or As; R=alkyl) granted direct access to transient amine‐substituted diphospha‐ and arsaphospha‐acrylamide analogues, (R2N)E=P(CONR2)1. Their facile formation allowed for a comprehensive reactivity study. Dimerization yielded the four‐membered rings (R2N)2E2P2(CONR2)2, whereas in the presence of excess Na[OCP], a stepwise [2+2] cycloaddition occured, leading to the sodium salts of carboxotripnictides [(R2N)EP2CO(CONR2)]−. These salts served as a reservoir of1, either by extrusion of Na[OCP] or by reaction with the appropriate (R2N)2ECl, giving the [4+2]‐cycloaddition products (R2N)EP(C6H10)(CONR2) in the presence of 2,3‐dimethylbutadiene. The formal conjugate addition product K[(tBuO)(R2N)PP(CONR2)] was obtained by reaction of Na[(R2N)PP2CO(CONR2)] withtBuOK. In addition, a rare diphosphadigalletane with a ladder‐type (R2N)2Ga2P2(CONR2)2core was isolated from the reaction of Na[OCP] with (R2N)2GaCl (R=alkyl). The unprecedented pnictogenyl carboxamide compounds were thoroughly characterized, including single‐crystal X‐ray structure determinations, and mechanisms for their formation were investigated by DFT calculations.
A Self‐Assembled ATP Probe for Melanoma Cell Imaging
Authors: Cheng Hong‐Bo , Sun ZhengWang , Kwon Nahyun , Wang Rui , Cui Yixin , Park Chang Ook , Yoon Juyoung
Published: January 2019

In this investigation, a new terpyridine metal complex was developed as a probe for selective detection of ATP and imaging of melanoma cells. The probe takes advantage of the ability of the metal complex to be transformed to its imaging competent turn‐on state through assembly with ATP.
Merging Visible‐Light Catalysis for the Direct Late‐Stage Group‐16–Trifluoromethyl Bond Formation
Authors: Ghiazza Clément , Billard Thierry , Tlili Anis
Published: January 2019

The use of visible light activation/photoredox chemistry for the generation of radical‐centered chalcogen–CF3 has gained widespread interest in the last past three years. Its subsequent reactivity for the synthesis of new chalcogen–CF3‐containing building blocks gained much attention. To date several methodologies have been developed addressing several challenges in modern organofluorine chemistry and enabled substantial progress in substrates scope and reaction conditions. This review describes these advancements with a particular focus on the reaction mechanisms.
Experimental study of hydrodynamics and bubble size distribution of an external loop airlift reactor
Authors: Lu Xia , Ding Yigang , Yu Jiuyang , Long Bingwen , Zheng Xiaotao
Published: January 2019

The most important factors influencing the performance of an external loop airlift reactor (ELALR) are local hydrodynamics and bubble size distribution (BSD). In this work, we studied the hydrodynamic characters and BSD in a laboratory scale ELALR. The velocity field of the riser was captured using the particle image velocimetry (PIV) technique and the bubble size distribution (BSD) was determined by digital image analysis (DIA). The results of the PIV measurement show that the flow has an unsteady structure, and the wake oscillation phenomena of the bubble and the vortex shedding are periodically asymmetrical. The gas holdup calculated by DIA correlates with the experimental data when the superficial gas velocity is < 0.02 m · s−1. With an increase in the superficial gas velocity, the probability density function (PDF) curve becomes flatter, changing from the unimodal to the bimodal. For the bimodal PDF curve, the peak of the small bubble is ∼1.5 mm, while the peak of lager bubble shifts from 4.5 to 5.5 mm with the increase in the superficial gas velocity. This work helps to provide insight into the mixing performance of the ELALR.
2,4‐Disubstituted 5‐Nitroimidazoles Potent against Clostridium difficile
Authors: Spitz Cédric , Mathias Fanny , Péchiné Séverine , Doan Tri Hanh Dung , Innocent Jean , Pellissier Sylvain , Di Giorgio Carole , Crozet Maxime D. , Janoir Claire , Vanelle Patrice
Published: January 2019

Metronidazole is one of the first‐line treatments for non‐severe Clostridium difficile infections (CDI). However, resistance limits its use in cases of severe and complicated CDI. Structure–activity relationships previously described for the 5‐nitroimidazole series have shown that functionalization at the 2‐ and 4‐positions can impart better activity against parasites and anaerobic bacteria than metronidazole. Herein we report the synthesis of new 2,4‐disubstituted 5‐nitroimidazole compounds that show potent antibacterial activity against C. difficile. We used a vicarious nucleophilic substitution of hydrogen (VNS) reaction to introduce a phenylmethylsulfone at the 4‐position and a unimolecular radical nucleophilic substitution (SRN1) reaction to introduce an ethylenic function at the 2‐position of the 5‐nitroimidazole scaffold.
The role of dose escalation and proton therapy in perioperative or definitive treatment of chondrosarcoma and chordoma: An analysis of the National Cancer Data Base
Authors: Palm Russell F. , Oliver Daniel E. , Yang George Q. , Abuodeh Yazan , Naghavi Arash O. , Johnstone Peter A. S.
Published: January 2019

Background

Chordomas and chondrosarcomas are a rare but challenging subset of tumors to treat; however, previous studies have shown benefits from proton therapy, which are thought to be primarily driven by prescription conformality permitting homogeneous tumor dosing and the allowance of higher doses. No retrospective studies to date have directly compared the outcomes of conventional and particle therapy or examined the role of high doses (specifically ≥70 Gy) in definitive radiotherapy (DRT) or perioperative radiotherapy (PRT) for both types of malignancies.

Methods

A total of 863 patients with chondrosarcoma and 715 patients with chordoma treated with nonpalliative proton or conventional radiation therapy with a dose range of 20 to 80 Gy and at least 15 months of follow‐up were identified from the National Cancer Data Base for the years 2003‐2014. The primary endpoint of overall survival (OS) was evaluated, and clinical features, including age, sex, grade, clinical stage, and Charlson‐Deyo comorbidity index, were compared.

Results

Patients receiving DRT were older and had more advanced disease. In DRT for chondrosarcoma, a high dose (40.6% vs 16.9%; P = .006) and proton therapy (75.0% vs 19.1%; P = .046) were associated with improved OS at 5 years in a multivariate analysis. In DRT for chordoma, proton therapy was associated with improved OS at 5 years in a multivariate analysis (100% vs 34.1%; P = .031), and a high dose for chordoma was significant for improved OS in a univariate analysis with both DRT (79.0% vs 54.1%; P = .027) and PRT (83.3% vs 77.4%; P = .007).

Conclusions

In the largest retrospective series to date, dose escalation and proton radiotherapy were associated with improved OS in patients with chondrosarcoma and chordoma despite limited follow‐up and access to particle therapy.
Synthesis and Characterization of Oxazaborinin Phosphonate for Blue OLED Emitter Applications
Authors: Köhling Jonas , Kozel Volodymyr , Jovanov Vladislav , Pajkert Romana , Tverdomed Sergey N. , Gridenco Oleg , Fugel Malte , Grabowsky Simon , Röschenthaler Gerd‐Volker , Wagner Veit
Published: January 2019

A blue‐light emitting material based on a boron complex containing heteroaromatic phosphonate ligand is synthesized and characterized. The Phospho‐Fries rearrangement is used in the synthesis route of the ligand as a convenient method of introducing phosphonate groups into phenols. Structural, thermal and photophysical properties of the resulting oxazaborinin phosphonate compound have been characterized. DFT geometry optimizations were studied as well as the spatial position and symmetry of the HOMO and LUMO. Good thermal stability up to 250 °C enables vacuum deposition methods next to solution processing. Combining the work function with the optical band gap from UV‐Vis measurements shows that band alignment is possible with standard contact materials. Photoluminescence reveals an emission peak at 428 nm, which is suitable for a blue light‐emitter.
Organotypic Culture of Bone‐Like Structures Using Composite Ceramic‐Fibrin Scaffolds
Authors: Iordachescu Alexandra , Williams Richard L. , Hulley Philippa A. , Grover Liam M.
Published: January 2019

We have developed an organotypic culture system that allows the production of bone tissue features on a centimeter scale. A composite, calcium phosphate–strained fibrin gel system is able to organize itself in the presence of osteoblastic cells, creating basic hierarchical units as seen in vivo, and can be modified to produce a range of other tissues that require such directional structuring. Constructs evolve over time into multi‐compositional structures containing a high mineral content and terminally differentiated, osteocyte‐like cells. These tissues can be cultured over extended durations (exceeding 1 year) and are responsive to a variety of chemical and biological agents. The platform can reduce the number of animals used in experimentation by acting as an intermediate stage in which more personalized research conditions can be generated. We provide a thorough description of the protocol used to successfully culture and modify this system, as well as guidance on compositional characterization. © 2019 by John Wiley & Sons, Inc.
Evaluating the Use of Nonrandomized Real‐World Data Analyses for Regulatory Decision Making
Authors: Franklin Jessica M. , Glynn Robert J. , Martin David , Schneeweiss Sebastian
Published: January 2019

The analysis of longitudinal healthcare data outside of highly controlled parallel‐group randomized trials, termed real‐world evidence (RWE), has received increasing attention in the medical literature. In this paper, we discuss the potential role ofRWEin drug regulation with a focus on the analysis of healthcare databases. We present several cases in whichRWEis already used and cases in whichRWEcould potentially support regulatory decision making. We summarize key issues that investigators and regulators should consider when designing or evaluating such studies, and we propose a structured process for implementing analyses that facilitates regulatory review. We evaluate the empirical evidence base supporting the validity, transparency, and reproducibility ofRWEfrom analysis of healthcare databases and discuss the work that still needs to be done to ensure that such analyses can provide decision‐ready evidence on the effectiveness and safety of treatments.