bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparing velocities and pressures in redox flow batteries with interdigitated and serpentine channels
Authors: Macdonald Malcolm , Darling Robert M. 
Published: January 2019

AbstractSerpentine channels adjacent to a thin, porous medium are a potentially attractive alternative to a conventional thick flow‐through electrode for redox flow batteries. The hydrodynamics of serpentine flow fields were investigated with computational fluid dynamics, a two‐dimensional model of the porous electrode based on Darcy's law, and a resistance network model at the scale of the active area. Predictions from the three models were used to map the available design space. The optimal electrode thickness, in terms of minimizing nonuniformity, was identified and compared to the result for an interdigitated flow field. Serpentine favors thicker electrodes and higher flows than interdigitated, in qualitative agreement with experimental findings. Furthermore, interdigitated designs deliver more uniform intraelectrode velocities and lower overall pressure drops than serpentine flow fields.
11,16‐Di‐tert‐butyl‐9,18‐diphenylbenzo[kl]benzo[8,9]triphenyleno [2,3‐b]xanthene: Synthesis, Photophysics, Self‐Assembly and Electroluminescent Properties
Authors: Tian Feng , Song Tingting , Wang Tao , Xiao Jinchong , Zhao Xiaohui 
Published: January 2019

AbstractA highly thermally stable twistarene, namely 11,16‐di‐tert‐butyl‐9,18‐diphenylbenzo[kl]benzo[8,9]triphenyleno[2,3‐b]xanthene (BTX), has been synthesized via a simple reaction, and its structure was unambiguously determined by single crystal X‐ray analysis with a twisted angle of 37.9° between plane C1‐C2‐C4 and plane C16‐C17‐C24. More interestingly, molecule BTX could self‐assembly into nanowires and nanospheres via simple reprecipitation, which were characterized by scanning electron microscope (SEM), UV‐vis absorption and emission spectra. The fabricated electroluminescent devices based on BTX as active ingredient presented a maximum brightness of 4355 cd m−2 (bias voltage at 9.0 V) with CIE coordinate of (0.14, 0.53).
Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering
Authors: Rüdt Matthias , Vormittag Philipp , Hillebrandt Nils , Hubbuch Jürgen 
Published: January 2019

AbstractVirus‐like particles (VLPs) have shown great potential as biopharmaceuticals in the market and in clinics. Nonenveloped, in vivo assembled VLPs are typically disassembled and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At the industrial scale, cross‐flow filtration (CFF) is the method of choice for performing reassembly by diafiltration. Here, we developed an experimental CFF setup with an on‐line measurement loop for the implementation of process analytical technology (PAT). The measurement loop included an ultraviolet and visible (UV/Vis) spectrometer as well as a light scattering photometer. These sensors allowed for monitoring protein concentration, protein tertiary structure, and protein quaternary structure. The experimental setup was tested with three Hepatitis B core Antigen (HBcAg) variants. With each variant, three reassembly processes were performed at different transmembrane pressures (TMPs). While light scattering provided information on the assembly progress, UV/Vis allowed for monitoring the protein concentration and the rate of VLP assembly based on the microenvironment of Tyrosine‐132. VLP formation was verified by off‐line dynamic light scattering (DLS) and transmission electron microscopy (TEM). Furthermore, the experimental results provided evidence of aggregate‐related assembly inhibition and showed that off‐line size‐exclusion chromatography does not provide a complete picture of the particle content. Finally, a Partial‐Least Squares (PLS) model was calibrated to predict VLP concentrations in the process solution. values of 0.947–0.984 were reached for the three HBcAg variants. In summary, the proposed experimental setup provides a powerful platform for developing and monitoring VLP reassembly steps by CFF.
Application of a TLR overexpression cell model in pyrogen detection
Authors: Han Qing , Hu Ruobi , Li Hui , Lei Zhen , Zhang Xuehui , Yu Xiuyan , Zhang Qun , Mao Yiqing , Wang Xi , Irwin David M. , Niu Gang , Tan Huanran 
Published: January 2019

AbstractPyrogens are components derived from microorganisms that induce complex inflammatory responses. Current approaches to detect pyrogens are complex and difficult to replicate, thus there is a need for new methods to detect pyrogens. We successfully constructed a pyrogen‐sensitive cell model by overexpressing Toll‐like receptor (TLR)2, TLR4, MD2, and CD14 in HEK293 cells. Since the cytokine IL‐6 is specifically released upon stimulation of the TLR2 and TLR4 signaling pathways in response to pyrogen stimulation, we used it as a read out for our assay. Our results show that IL‐6 is released in response to trace amounts of pyrogens in our cell model. Pyrogen incubation times and concentrations were explored to determine the sensitivity of our cell model, and was found to be sensitive to 0.05 EU/ml of LPS and 0.05 ug/ml of LTA after stimulation for 5 hr. Our TLR overexpressing cell model, with IL‐6 as readout, could be a new method for in vitro testing of pyrogens and applicable for evaluating the safety of drugs.
Nitrous oxide production in autotrophic nitrogen removal granular sludge: A modeling study
Authors: Chen Xueming , Ni Bing‐Jie , Sin Gürkan 
Published: January 2019

AbstractThe sustainability of autotrophic granular system performing partial nitritation and anaerobic ammonium oxidation (anammox) for complete nitrogen removal is impaired by the production of nitrous oxide (N2O). A systematic analysis of the pathways and affecting parameters is, therefore, required for developing N
2O mitigation strategies. To this end, a mathematical model capable of describing different N
2O production pathways was defined in this study by synthesizing relevant mechanisms of ammonium‐oxidizing bacteria (AOB), nitrite‐oxidizing bacteria, heterotrophic bacteria (HB), and anammox bacteria. With the model validity reliably tested and verified using two independent sets of experimental data from two different autotrophic nitrogen removal biofilm/granular systems, the defined model was applied to reveal the underlying mechanisms of N
2O production in the granular structure as well as the impacts of operating conditions on N
2O production. The results show that: (a) in the aerobic zone close to the granule surface where AOB contribute to N
2O production through both the AOB denitrification pathway and the NH
2OH pathway, the co‐occurring HB consume N
2O produced by AOB but indirectly enhance the N
2O production by providing NO from NO
2
− reduction for the NH
2OH pathway, (b) the inner anoxic zone of granules with the dominance of anammox bacteria acts as a sink for NO
2
− diffusing from the outer aerobic zone and, therefore, reduces N
2O production from the AOB denitrification pathway, (c) operating parameters including bulk DO, influent NH
4
+, and granule size affect the N
2O production in the granules mainly by regulating the NH
2OH pathway of AOB, accounting for 34–58% of N
2O turnover, and (d) the competition between the NH
2OH pathway and heterotrophic denitrification for nitric oxide leads to the positive role of HB in reducing N
2O production in the autotrophic nitrogen removal granules, which could be further enhanced in the presence of a proper level of influent organics.
Modulation of the central carbon metabolism of Corynebacterium glutamicum improves malonyl‐CoA availability and increases plant polyphenol synthesis
Authors: Milke Lars , Ferreira Patrícia , Kallscheuer Nicolai , Braga Adelaide , Vogt Michael , Kappelmann Jannick , Oliveira Joana , Silva Ana Rita , Rocha Isabel , Bott Michael , Noack Stephan , Faria Nuno , Marienhagen Jan 
Published: January 2019

AbstractIn recent years microorganisms have been engineered towards synthesizing interesting plant polyphenols such as flavonoids and stilbenes from glucose. Currently, the low endogenous supply of malonyl‐CoA, indispensable for plant polyphenol synthesis, impedes high product titers. Usually, limited malonyl‐CoA availability during plant polyphenol production is avoided by supplementing fatty acid synthesis‐inhibiting antibiotics such as cerulenin, which are known to increase the intracellular malonyl‐CoA pool as a side effect. Motivated by the goal of microbial polyphenol synthesis being independent of such expensive additives, we used rational metabolic engineering approaches to modulate regulation of fatty acid synthesis and flux into the tricarboxylic acid cycle (TCA cycle) in Corynebacterium glutamicum strains capable of flavonoid and stilbene synthesis. Initial experiments showed that sole overexpression of genes coding for the native malonyl‐CoA‐forming acetyl‐CoA carboxylase is not sufficient for increasing polyphenol production in
C. glutamicum. Hence, the intracellular acetyl‐CoA availability was also increased by reducing the flux into the TCA cycle through reduction of citrate synthase activity. In defined cultivation medium, the constructed
C. glutamicum strains accumulated 24 mg·L
−1 (0.088 mM) naringenin or 112 mg·L
−1 (0.49 mM) resveratrol from glucose without supplementation of phenylpropanoid precursor molecules or any inhibitors of fatty acid synthesis.
Stable recombinant production of codon‐scrambled lubricin and mucin in human cells
Authors: Shurer Carolyn R. , Wang Yuyan , Feeney Elizabeth , Head Shelby E. , Zhang Victoria X. , Su Jin , Cheng Zhu , Stark Morgan A. , Bonassar Lawrence J. , Reesink Heidi L. , Paszek Matthew J. 
Published: January 2019

AbstractWidespread therapeutic and commercial interest in recombinant mucin technology has emerged due to the unique ability of mucin glycoproteins to hydrate, protect, and lubricate biological surfaces. However, recombinant production of the large, highly repetitive domains that are characteristic of mucins remains a challenge in biomanufacturing likely due, at least in part, to the inherent instability of DNA repeats in the cellular genome. To overcome this challenge, we exploit codon redundancy to encode desired mucin polypeptides with minimal nucleotide repetition. The codon‐scrambling strategy was applied to generate synonymous genes, or “synDNAs,” for two mucins of commercial interest: lubricin and mucin 1. Stable, long‐term recombinant production in suspension‐adapted human 293‐F cells was demonstrated for the synonymous lubricin complementary DNA (cDNA), which we refer to as SynLubricin. Under optimal conditions, a 293‐F subpopulation produced recombinant SynLubricin at more than 200 mg/L of media and was stable throughout 2 months of continuous culture. Functionality tests confirmed that the recombinant lubricin could effectively inhibit cell adhesion and lubricate cartilage explants. Together, our work provides a viable workflow for cDNA design and stable mucin production in mammalian host production systems.
Fine‐tuning the (2S)‐naringenin synthetic pathway using an iterative high‐throughput balancing strategy
Authors: Zhou Shenghu , Lyu Yunbin , Li Huazhong , Koffas Mattheos A.G. , Zhou Jingwen 
Published: January 2019

AbstractMetabolic engineering consistently demands to produce the maximum carbon and energy flux to target chemicals. To balance metabolic flux, gene expression levels of artificially synthesized pathways usually fine‐tuned using multimodular optimization strategy. However, forward construction is an engineering conundrum because a vast number of possible pathway combinations need to be constructed and analyzed. Here, an iterative high‐throughput balancing (IHTB) strategy was established to thoroughly fine‐tune the (2S)‐naringenin biosynthetic pathway. A series of gradient constitutive promoters from Escherichia coli were randomly cloned upstream of pathway genes, and the resulting library was screened using an ultraviolet spectrophotometry–fluorescence spectrophotometry high‐throughput method, which was established based on the interactions between AlCl3 and (2S)‐naringenin. The metabolic flux of the screened high‐titer strains was analyzed and iterative rounds of screening were performed based on the analysis results. After several rounds, the metabolic flux of the (2S)‐naringenin synthetic pathway was balanced, reaching a final titer of 191.9 mg/L with 29.2 mg/L p‐coumaric acid accumulation. Chalcone synthase was speculated to be the rate‐limiting enzyme because its expression level was closely related to the production of both (2S)‐naringenin and p‐coumaric acid. The established IHTB strategy can be used to efficiently balance multigene pathways, which will accelerate the development of efficient recombinant strains.
Glucose Isomerization and Epimerization over Metal‐Organic Frameworks with Single‐Site Active Centers
Authors: Luo Qun‐Xing , Zhang Yuan‐Bao , Qi Long , Scott Susannah L. 
Published: January 2019

AbstractRegulating reaction pathway of glucose isomerization and epimerization is essential for production of high‐fructose corn syrup and rare sugars. Herein, we show a molecular‐level observation on glucose transformation using metal‐organic frameworks (MOFs) with single‐site active centers (SSACs) as heterogeneous catalysts. It is found that Lewis acidic Cr (III) sites of MIL‐101 prefer to catalyze glucose‐to‐fructose isomerization in either water or methanol solvent. Elevating reaction temperature can promote glucose‐to‐mannose epimerization but without intramolecular carbon shift. The Lewis acidic Zr (IV) sites of UiO‐66 can catalyze glucose isomerization and epimerization in aqueous media simultaneously, where glucose‐to‐mannose epimerization proceeds by way of intramolecular carbon‐skeleton rearrangement (C‐1 and C‐2), following the cleavage of the bond between C‐2 and C‐3 and formation of new bond between C‐1 and C‐3. It is proposed that the difference in catalytic behavior might be related to the polarizability of SSACs and particularly to their local coordination environment.
Selective Aerobic Oxidation of Alcohols over Gold‐Palladium Alloy Catalysts Using Air at Atmospheric Pressure in Water
Authors: Zhang Wei , Xiao Ziqiang , Wang Jiajun , Fu Wenqin , Tan Rong , Yin Donghong 
Published: January 2019

AbstractA series of bimetallic Au−Pd alloy nanoparticles (NPs) with varied Au/Pd molar ratios was supported on Gamma‐alumina (γ‐Al2O3) surface through the co‐impregnation‐reduction method using HAuCl4 and PdCl2 as metal precursors. Characterization results suggested the high dispersion of Au−Pd alloy NPs, as well as the interplay between the two compositions. Benefitting from the synergistic effects of Au−Pd alloying, the bimetallic Au‐Pdx@γ‐Al2O3 catalysts were highly efficient for selective aerobic oxidation of various alcohols either aromatic or aliphatic in water using air at atmospheric pressure as a sole oxidant without the need for any cocatalyst. Quantitative yields of corresponding aldehydes or ketones were achieved over Au‐Pd1.2@γ‐Al2O3 within 2 h, whereas pure Au@γ‐Al2O3 or Pd@γ‐Al2O3 was far less efficient. More importantly, the “alloying effect” appeared to stabilize the bimetallic NPs against aggregation and poisoning, which made the Au‐Pdx@γ‐Al2O3 more stable and reusable in the aerobic oxidation of alcohols.
Direct Electrolysis of CO2 in a Symmetrical Solid Oxide Electrolysis Cell with Spinel MnCo2O4 as Electrode
Authors: Zhang Lingling , Tian Yunfeng , Liu Yanya , Jia Lichao , Yang Jun , Chi Bo , Pu Jian , Li Jian 
Published: January 2019

AbstractA novel symmetrical solid oxide electrolysis cell (S‐SOEC) utilizing a spinel structured MnCo2O4 electrode is investigated for pure CO2 electrolysis. The electrode is prepared through an impregnation method and is confirmed to have excellent performance for CO2 electrolysis, with a current density of 0.75 A cm−2 at an applied voltage of 1.5 V at 800 °C. The MnCo2O4 electrodes also show good stability for long‐term pure CO2 electrolysis for more than 80 h. The study suggests that MnCo2O4 is a potential electrode for pure CO2 electrolysis in S‐SOECs.
9,9′‐Bicarbazole: New Molecular Skeleton for Organic Light‐Emitting Diodes
Authors: Liu Xiang‐Yang , Zhang Yuan‐Lan , Fei Xiyu , Liao Liang‐Sheng , Fan Jian 
Published: January 2019

AbstractCarbazole is a classic tricyclic aromatic compound that has been widely used in organic optoelectronics. Appropriate functionalization on its aromatic rings will significantly increase the possibilities for its application as an optoelectronic material. Position engineering of carbazole not only leads to its structural diversity, but also substantially enriches its functionality. Bicarbazoles have 15 isomers, most of which are well studied and have been applied in organic light‐emitting diodes (OLEDs). However, one isomer, 9,9′‐bicarbazole, is rarely investigated as an OLED material. Therefore, two 9,9′‐bicarbazole derivatives, 3,3′‐di(10H‐phenoxazin‐10‐yl)‐9,9′‐bicarbazole and 3,3′‐di(10H‐phenothiazin‐10‐yl)‐9,9′‐bicarbazole, have been designed and prepared for use as host materials for green and red OLEDs. These two compounds demonstrated good device performances, and it is believed that the 9,9′‐bicarbazole building block could be a novel platform for the design of efficient host materials for OLEDs.
Quantitative representation of floral colors
Authors: Athira K. , Sooraj N.P. , Jaishanker R. , Saroj Kumar V. , Sajeev C.R. , Pillai M.S. , Govind A. , Dadhwal V.K. 
Published: January 2019

AbstractHuman and insect pollinator perceived floral colors of 81 species of angiosperms (flowering plants) from Trivandrum (Kerala, India) was represented using the CIE 1976 L*a*b* color space and color hexagon, respectively. The floral color difference among human perceived red, yellow, and blue‐hued flowers and that of each flower from its respective pure hue was calculated using the CIE ΔE 2000 formula. Human perceived floral color difference values were consistently higher than 3.5, indicating the uniqueness of floral colors. Flowers perceived red and yellow by humans were dominant and of comparable proportions. Insect pollinators perceive most of the flowers as blue‐green. Quantitative representation of human and pollinator perceived floral colors would be invaluable to understand the information broadcasted by flowers. It can form the basis of flower grading in the floriculture industry and underpin objectivity in evolving the framework for national pollinator strategies.
Electrochemical Difluoromethylation of Electron‐Deficient Alkenes
Authors: Xu He‐Huan , Song Jinshuai , Xu Hai‐Chao 
Published: January 2019

AbstractElectrochemical 1,2‐hydroxydifluoromethylation and C−H difluoromethylation of acrylamides were developed by using CF2HSO2NHNHBoc as the source of the CF2H group. These electricity‐powered oxidative alkene functionalization reactions do not need transition‐metal catalysts or chemical oxidants. The reaction outcome, 1,2‐difuntionalization or C−H functionalization, is determined by the substituents on the amide nitrogen atom of the acrylamides instead of by the reaction conditions.
Dual Quantum Dot‐Decorated Bismuth Vanadate Photoanodes for Highly Efficient Solar Water Oxidation
Authors: Luan Peng , Zhang Xiaolong , Zhang Ying , Li Zhijun , Bach Udo , Zhang Jie 
Published: January 2019

AbstractPhoto‐induced charge separation and photon absorption play important roles in determining the performance of the photoelectrocatalytic water splitting process. In this work, we utilize dual quantum dots (QDs), consisting of BiVO4 and carbon, to fabricate a hybrid homojunction‐based BiVO4 photoanode for efficient and stable solar water oxidation. Formation of homojunctions, by decorating as‐prepared BiVO4 substrate with BiVO4 QDs, enhances the charge separation efficiency by 1.3 times. This enhancement originates from lattice match, which benefits charge transfer across the interface. Furthermore, the use of carbon QDs as a stable photosensitizer effectively extends the photon absorption limit from 520 nm to over 700 nm, yielding an incident photon‐to‐electron conversion efficiency of 6.0 %, even at 600 nm at 1.23 V versus RHE. Finally, a remarkable photocurrent density of 6.1 mA cm−2 at 1.23 V was recorded after depositing FeOOH/NiOOH as cocatalysts, thereby, reaching 82 % of the theoretical efficiency for BiVO4.
Tumor implantation following percutaneous endoscopic gastrostomy insertion for head and neck and oesophageal cancer: Review of the literature
Authors: Rowell Nicholas P. 
Published: January 2019

AbstractBackgroundBecause of publication bias, there is uncertainty about the true incidence of tumor seeding or implantation in patients with head and neck or oesophageal cancer undergoing percutaneous endoscopic gastrostomy (PEG) insertion.MethodsIn order to obtain a more reliable estimate of risk, a systematic review was undertaken. Randomized or non‐randomized studies and case reports were identified by electronic searching. A risk of bias assessment was carried out for each study.ResultsNinety‐eight cases from 74 published case reports and 1 unpublished case were identified. Synchronous distant metastases were present in 37%. Analysis of case series (6192 patients) considered to carry a moderate risk of bias suggests an incidence of seeding after PEG insertion of 0.32%. Studies carrying a lower risk of bias indicate a risk of seeding closer to 1 in 2000.ConclusionThe true risk of seeding after PEG insertion is probably less than 1 in 1000.
Simulated body fluid and the novel bioactive materials derived from it
Authors: Kokubo Tadashi , Yamaguchi Seiji 
Published: January 2019

AbstractProfessor Larry Hench first reported that certain glasses are able to spontaneously bond to living bone in 1970. This discovery stimulated research into new kinds of bone‐bonding materials. However, there were no guiding principles for this purpose, and many animals were sacrificed in the effort to establish them. The present authors proposed in 1991 that the bone‐bonding capacity of a material could be evaluated by examining apatite formation on its surface in an acellular simulated body fluid (SBF), without the need of performing any animal experiments. Various kinds of novel bone‐bonding bioactive materials based on Ti metal and its alloys with a number of different functions have been developed using SBF. Some of these have entered clinical use as important bone‐repairing materials. Without the method of SBF evaluation, these novel materials would not have been developed. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 968–977, 2019.