bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterostructured Inter‐Doped Ruthenium–Cobalt Oxide Hollow Nanosheet Arrays for Highly Efficient Overall Water Splitting
Authors: Wang Cheng , Qi Limin 
Published: June 2020

AbstractThe development of transition‐metal‐oxides (TMOs)‐based bifunctional catalysts toward efficient overall water splitting through delicate control of composition and structure is a challenging task. Herein, the rational design and controllable fabrication of unique heterostructured inter‐doped ruthenium–cobalt oxide [(Ru–Co)Ox] hollow nanosheet arrays on carbon cloth is reported. Benefiting from the desirable compositional and structural advantages of more exposed active sites, optimized electronic structure, and interfacial synergy effect, the (Ru–Co)Ox nanoarrays exhibited outstanding performance as a bifunctional catalyst. Particularly, the catalyst showed a remarkable hydrogen evolution reaction (HER) activity with an overpotential of 44.1 mV at 10 mA cm−2 and a small Tafel slope of 23.5 mV dec−1, as well as an excellent oxygen evolution reaction (OER) activity with an overpotential of 171.2 mV at 10 mA cm−2. As a result, a very low cell voltage of 1.488 V was needed at 10 mA cm−2 for alkaline overall water splitting.
Unexpected Acetylation of Endogenous Aliphatic Amines by Arylamine N‐Acetyltransferase NAT2
Authors: Conway Louis P. , Rendo Veronica , Correia Mário S. P. , Bergdahl Ingvar A. , Sjöblom Tobias , Globisch Daniel 
Published: June 2020

AbstractN‐Acetyltransferases play critical roles in the deactivation and clearance of xenobiotics, including clinical drugs. NAT2 has been classified as an arylamine N‐acetyltransferase that mainly converts aromatic amines, hydroxylamines, and hydrazines. Herein, we demonstrate that the human arylamine N‐acetyltransferase NAT2 also acetylates aliphatic endogenous amines. Metabolomic analysis and chemical synthesis revealed increased intracellular concentrations of mono‐ and diacetylated spermidine in human cell lines expressing the rapid compared to the slow acetylator NAT2 phenotype. The regioselective N8‐acetylation of monoacetylated spermidine by NAT2 answers the long‐standing question of the source of diacetylspermidine. We also identified selective acetylation of structurally diverse alkylamine‐containing drugs by NAT2, which may contribute to variations in patient responses. The results demonstrate a previously unknown functionality and potential regulatory role for NAT2, and we suggest that this enzyme should be considered for re‐classification.
Quantitative Supramolecular Heterodimerization for Efficient Energy Transfer
Authors: Wu Guanglu , Huang Zehuan , Scherman Oren A. 
Published: June 2020

AbstractThe challenge of quantitatively forming self‐assembled heterodimers without other equilibrium by‐products is overcome through self‐sorting favored by the introduction of designed shape‐complementary moieties. Such a supramolecular strategy based on cucurbit[8]uril‐directed dimerization is further applied to generate hetero‐chromophore dimers quantitatively, leading to efficient energy transfer (>85 %) upon photoexcitation.
Ørsted and Bunsen: Voltaic Batteries, Electric Arcs, Electromagnetism, and Electrolysis
Authors: Wentrup Curt 
Published: June 2020

Abstract200 years ago Ørsted laid the foundation of electromagnetism in his famous experiment in which a magnetic needle is deflected in the electrical field of a platinum wire. For this he used his own Cu‐Zn trough battery, which was among the best then available, but 21 years later it was surpassed by the coal‐zinc battery invented by Bunsen, which became highly successful and acclaimed. That year, 1841, Bunsen made his first direct contact with Scandinavia when he visited Berzelius in Stockholm, Palmstedt in Gothenburg, and Ørsted, Scharling, and Zeise in Copenhagen. Like almost everybody in continental Europe, they adopted Bunsen's battery, and Ørsted used it for his experiments with a very large electromagnet. The paths of Ørsted's and Bunsen's research crossed again much later through the synthesis of elemental aluminum, which was first achieved by Ørsted in 1825 (although it was probably not obtained as the pure metal) and performed quite differently by Bunsen, by electrolysis using his coal‐zinc battery, in 1854.
Cavitand‐Based Pd‐Pyridyl Coordination Capsules: Guest‐Induced Homo‐ or Heterocapsule Selection and Applications of Homocapsules to the Protection of a Photosensitive Guest and Chiral Capsule Formation
Authors: Nakamura Munechika , Tsukamoto Yoshimi , Ueta Takuro , Sei Yoshihisa , Fukushima Takanori , Yoza Kenji , Kobayashi Kenji 
Published: June 2020

AbstractA 2 : 4 mixture of tetrakis[4‐(4‐pyridyl)phenyl]cavitand (1) or tetrakis[4‐(4‐pyridyl)phenylethynyl]cavitand (2) and Pd(dppp)(OTf)2 self‐assembles into a homocapsule {12 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C1) or {22 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C2), respectively, through Pd−Npy coordination bonds. A 1 : 1 : 4 mixture of 1, 2, and Pd(dppp)(OTf)2 produced a mixture of homocapsules C1, C2, and a heterocapsule {1 ⋅ 2 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C3) in a 1 : 1 : 0.98 mole ratio. Selective formation (self‐sorting) of homocapsules C1 and C2 or heterocapsule C3 was controlled by guest‐induced encapsulation under thermodynamic control. Applications of Pd−Npy coordination capsules with the use of 1 were demonstrated. Capsule C1 serves as a guard nanocontainer for trans‐4,4′‐diacetoxyazobenzene to protect against the trans‐to‐cis photoisomerization by encapsulation. A chiral capsule {12 ⋅ [Pd((R)‐BINAP)]4}8+ ⋅ (TfO−)8 (C5) was also constructed. Capsule C5 induces supramolecular chirality with respect to prochiral 2,2′‐bis(alkoxycarbonyl)‐4,4′‐bis(1‐propynyl)biphenyls by diastereomeric encapsulation through the asymmetric suppression of rotation around the axis of the prochiral biphenyl moiety.
Biological properties and structural characterization of a novel rhamnolipid like‐biosurfactants produced by Lactobacillus casei subsp. casei TM1B
Authors: Mouafo Hippolyte T. , Mbawala Augustin , Somashekar Devappa , Tchougang Hervé M. , Harohally Nanishankar V. , Ndjouenkeu Robert 
Published: June 2020

AbstractBiosurfactants are microbial surface‐active compounds with antimicrobial and antioxidant activities that display a range of physiological functions. In this study, a strain isolated from a Cameroonian fermented milk “pendidam” and identified as Lactobacillus casei subsp. casei TM1B was used for biosurfactants production. The biosurfactants produced by L. casei TM1B with molasses as the substrate had a good surface (40.77 mN/m) and emulsifying (84.50%) activities. The scavenging of the ABTS+• radical (IC50 value of 0.60 ± 0.03 mg/mL) by the biosurfactants was found to be higher than that of DPPH• radical (IC50 value of 0.97 ± 0.13 mg/mL). The maximum chelating activity of biosurfactants (82.29%) was observed at 3.5 mg/mL. The biologically active compound of the biosurfactants produced by L. casei TM1B was identified as 2,5‐O‐methylrhamnofuranosyl‐palmitate, a novel rhamnolipid‐like biosurfactant by using chemical, Fourier transform infrared spectroscopy, gas chromatography‐mass spectrometry, and NMR analysis. The biosurfactants were bactericidal against several Gram‐negative and Gram‐positive pathogens (minimum inhibitory concentration values ranged from 3.22 to 12.83 mg/mL), and scanning electron microscope analysis revealed bacterial cell walls and membranes as main targets.
Engineered citrate synthase improves citramalic acid generation in Escherichia coli
Authors: Wu Xianghao , Tovilla‐Coutiño D. Brisbane , Eiteman Mark A. 
Published: June 2020

AbstractThe microbial product citramalic acid (citramalate) serves as a five‐carbon precursor for the chemical synthesis of methacrylic acid. This biochemical is synthesized in Escherichia coli directly by the condensation of pyruvate and acetyl‐CoA via the enzyme citramalate synthase. The principal competing enzyme with citramalate synthase is citrate synthase, which mediates the condensation reaction of oxaloacetate and acetyl‐CoA to form citrate and begin the tricarboxylic acid cycle. A deletion in the gltA gene coding citrate synthase prevents acetyl‐CoA flux into the tricarboxylic acid cycle, and thus necessitates the addition of glutamate. In this study the E. coli citrate synthase was engineered to contain point mutations intended to reduce the enzyme's affinity for acetyl‐CoA, but not eliminate its activity. Cell growth, enzyme activity and citramalate production were compared in several variants in shake flasks and controlled fermenters. Citrate synthase GltA[F383M] not only facilitated cell growth without the presence of glutamate, but also improved the citramalate production by 125% compared with the control strain containing the native citrate synthase in batch fermentation. An exponential feeding strategy was employed in a fed‐batch process using MEC626/pZE12‐cimA harboring the GltA[F383M] variant, which generated over 60 g/L citramalate with a yield of 0.53 g citramalate/g glucose in 132 hr. These results demonstrate protein engineering can be used as an effective tool to redirect carbon flux by reducing enzyme activity and improve the microbial production of traditional commodity chemicals.
microRNA‐124‐3p inhibits tumourigenesis by targeting mitogen‐activated protein kinase 4 in papillary thyroid carcinoma
Authors: Sun Yu , Zhang Liwei , Zhang Suzhen 
Published: June 2020

AbstractThe study aimed to investigate the role of miR‐124‐3p and its potential molecular mechanism in papillary thyroid cancer (PTC). The expression of miR‐124‐3p and mitogen‐activated protein kinase 4 (MAP2K4) in human thyroid follicular epithelial cell line (NTHY‐ORI3‐1) and human papillary thyroid carcinoma cell lines (SW1736, BCPAP, TPC‐1 and K1) was measured by RT‐qPCR. Cell proliferation was measured by CCK‐8, while cell cycle and apoptosis rate were measured by flow cytometry. Invasive ability and migrative ability were measured by transwell assay and wound healing assay, respectively. Western blot was used to detect the levels of relative proteins. In vivo, TPC‐1 cells transfected with miR‐124‐3p mimic were subcutaneously injected into the flank of the mice to form tumour. After successful modelling, mice were divided into two groups (n = 10): Control group and miR‐124‐3p mimic group. The present study showed that miR‐124‐3p was lowly expressed, while MAP2K4 was highly expressed in PTC cell lines. Besides, miR‐124‐3p targeted MAP2K4 and negatively regulated MAP2K4 in TPC‐1 cells. In addition, miR‐124‐3p inhibited the proliferation and motility, and induced apoptosis and cell cycle arrest of TPC‐1 cells by inactivating MAP2K4/JNK/JunD pathway. Furthermore, miR‐124‐3p inhibited tumour formation by downregulating MAP2K4 level in vivo. In conclusion, the study provided a novel molecular mechanism of miR‐124‐3p in the progress of PTC.Significance of the studyPapillary thyroid cancer (PTC) is the most important pathological type of thyroid cancer, accounting for 80% of thyroid cancer. miR‐124‐3p exhibited significant inhibitory role in the transformation and development of malignant tumours. However, in PTC, the roles and its potential molecular mechanism are unclear. Here, the study investigated the roles of miR‐124‐3p in the progress of PTC and its potential molecular mechanism. We found that miR‐124‐3p inhibited the proliferation and motility, and induced apoptosis and cell cycle arrest in PTC cells. This study provided a novel molecular mechanism of miR‐124‐3p in the progress of PTC.
Insight into Isoprenoid Biosynthesis by Functional Analysis of Isoprenyl Diphosphate Synthases from Mycobacterium vanbaalenii and Mycobacterium tuberculosis
Authors: Abe Tohru , Ozaki Sadamu , Ueda Daijiro , Sato Tsutomu 
Published: June 2020

AbstractComprehensive functional analyses of E‐isoprenyl diphosphate synthases (E‐IDSs) from nonpathogenic Mycobacterium vanbaalenii have been performed. Mv0992 and Mv1577 represent a nonaprenyl diphosphate (E‐C45) synthase and a geranylgeranyl diphosphate (E‐C20) synthase, respectively. Although Mv3536 was identified as an E‐C20 synthase using a single enzyme, co‐incubation of Mv3536 and Z‐IDSs (Mv4662 and Mv3822) strongly suggested it releases an intermediate geranyl diphosphate (E‐C10) during a continuous condensation reaction. Mv0992 and Mv3536 functions differed from those of the previously reported pathogenic Mycobacterium tuberculosis homologues Rv0562 and Rv2173, respectively. Re‐analysis of Rv0562 and Rv2173 demonstrated that their functions were similar to those of Mv0992 and Mv3536 (Rv0562: E‐C45 synthase; Rv2173: E‐C10–15 synthase). The newly proposed functions of Rv0562 and Rv2173 would be in the biosynthesis of menaquinone and glycosyl carrier lipids essential for growth. Furthermore, a reduced allylic diphosphate could be used as the Z‐IDS of the Mv3822 substrate, thereby introducing a potentially novel pathway of cyclic sesquarterpene biosynthesis.
On the Remarkable Performance of Silver‐based Alloy Nanoparticles in 4‐Nitrophenol Catalytic Reduction
Authors: Varshney Shalaka , Bar‐Ziv Ronen , Zidki Tomer 
Published: June 2020

AbstractElimination of nitro groups from the toxic aromatic nitro compounds is of great environmental importance. A catalytic study of the 4‐nitrophenol reduction on the surface of metallic and alloy nanoparticles is presented. The silver‐based catalysts, with low amounts of platinum (10 % Pt), exhibit excellent catalytic activity without an induction‐time, which fulfills both the performance and cost requirements for the catalytic reduction of 4‐nitrophenol to 4‐aminophenol in the presence of NaBH4. The apparent rate constant of 59×10−3 s−1 and an extremely high activity parameter value of 13,600 s−1 g−1 are reported for the first time. This mechanistic study suggests that hydrides are the active species for 4‐nitrophenol reduction, and that the composition of the alloy can affect the reactivity and competition with the hydrogen evolution reaction. Our work opens future possibilities for the optimal design of efficient and low‐cost catalysts for redox processes and neutralization of organic pollutants.
Obesity, race, and long‐term prostate cancer outcomes
Authors: Vidal Adriana C. , Oyekunle Taofik , Howard Lauren E. , De Hoedt Amanda M. , Kane Christopher J. , Terris Martha K. , Cooperberg Matthew R. , Amling Christopher L. , Klaassen Zachary , Freedland Stephen J. , Aronson William J. 
Published: June 2020

BackgroundThe authors previously found that obesity was linked with prostate cancer (PC)–specific mortality (PCSM) among men who underwent radical prostatectomy (RP). Herein, in a larger RP cohort, the authors investigated whether the association between obesity and long‐term PC outcomes, including PCSM, differed by race.MethodsData from 5929 patients who underwent RP and were in the Shared Equal Access Regional Cancer Hospital (SEARCH) database were analyzed. Prior to RP, body mass index (BMI) was measured and recorded in the medical records. BMI was categorized as normal weight (<25 kg/m2), overweight (25‐29.9 kg/m2), and obese (≥30 kg/m2). The authors assessed the association between BMI and biochemical disease recurrence (BCR), castration‐resistant prostate cancer (CRPC), metastasis, and PCSM, accounting for confounders.ResultsOf the 5929 patients, 1983 (33%) were black, 1321 (22%) were of normal weight, 2605 (44%) were overweight, and 2003 (34%) were obese. Compared with white men, black men were younger; had higher prostate‐specific antigen levels; and were more likely to have a BMI ≥30 kg/m2, seminal vesicle invasion, and positive surgical margins (all P ≤ .032). During a median follow‐up of 7.4 years, a total of 1891 patients (32%) developed BCR, 181 patients (3%) developed CRPC, 259 patients (4%) had metastasis, and 135 patients (2%) had died of PC. On multivariable analysis, obesity was found to be associated with an increased risk of PCSM (hazard ratio, 1.78; 95% confidence interval, 1.04‐3.04 [P = .035]). No interaction was found between BMI and race in predicting PCSM (P ≥ .88), BCR (P ≥ .81), CRPC (P ≥ .88), or metastasis (P ≥ .60). Neither overweight nor obesity was associated with risk of BCR, CRPC, or metastasis (all P ≥ .18).ConclusionsObese men undergoing RP at several Veterans Affairs hospitals were found to be at an increased risk of PCSM, regardless of race.
MEK or ERK inhibition effectively abrogates emergence of acquired osimertinib resistance in the treatment of epidermal growth factor receptor–mutant lung cancers
Authors: Gu Jiajia , Yao Weilong , Shi Puyu , Zhang Guojing , Owonikoko Taofeek K. , Ramalingam Suresh S. , Sun Shi‐Yong 
Published: June 2020

BackgroundThe majority of patients with non–small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutations respond well to osimertinib (AZD9291), a third‐generation, mutation‐selective EGFR inhibitor. The current study focuses on determining whether targeting MEK/ERK signaling prevents or delays the development of acquired resistance to osimertinib.MethodsDrug effects on cell survival were determined by measuring cell number alterations. Apoptosis was assessed with flow cytometry for the detection of annexin V–positive cells and with Western blotting for protein cleavage. Alterations of proteins in cells were detected with Western blotting. Drug effects on delaying the emergence of osimertinib resistance were evaluated with colony formation in vitro and xenografts in nude mice in vivo.ResultsOsimertinib combined with an MEK or ERK inhibitor synergistically decreased cell survival with enhanced induction of apoptosis in EGFR‐mutant NSCLC cells but not in EGFR wild‐type NSCLC cells. These combinations were also very effective in killing cell clones with primary intrinsic resistance to osimertinib. Continuous and intermittent pharmacologic inhibition of MEK/ERK signaling delayed the emergence of osimertinib resistance both in vitro and in vivo.ConclusionsThese results provide strong preclinical evidence in support of targeting MEK/ERK signaling as a strategy for delaying or preventing acquired resistance to osimertinib in the clinic to improve the long‐term therapeutic efficacy of osimertinib. From a clinical standpoint, the data support the evaluation of an intermittent treatment schedule of osimertinib in combination with an MEK or ERK inhibitor in patients with EGFR‐mutated NSCLC.
Subtherapeutic Acetazolamide Doses as a Noninvasive Method for Assessing Medication Adherence
Authors: Hampson Aidan J. , Schroeder Jennifer R. , Ellefsen Kayla N. , Yammine Luba , Epstein David H. , Preston Kenzie L. , Huestis Marilyn A. , Verrico Christopher D. 
Published: June 2020

Adherence monitoring is a vital component of clinical efficacy trials, as the regularity of medication consumption affects both efficacy and adverse effect profiles. Pill‐counts do not confirm consumption, and invasive plasma assessments can only assistpost hocassessments. We previously reported on the pharmacokinetics of a potential adherence marker to noninvasively monitor dosage consumption during a trial without breaking a blind. We reported that consumption cessation of subtherapeutic 15 mg acetazolamide (ACZ) doses showed a predictable urinary excretion decay that was quantifiable for an extended period. The current study describes the clinical implementation of 15 mg ACZ doses as an adherence marker excipient in distinct cohorts taking ACZ for different “adherence” durations. We confirm that ACZ output did not change (accumulate) during 18–20 days of adherence, and developed and assessed urinary cutoffs as nonadherence indicators. We demonstrate that whereas an absolute concentration cutoff (989 ng/mL) lacked sensitivity, a creatinine normalized equivalent (1,376 ng/mg ACZ) was highly accurate at detecting nonadherence. We also demonstrate that during nonadherent phases of three trials, creatinine‐normalized urinary ACZ elimination was reproducible within and across trials with low variability. Excretion was first order, with a decay half‐life averaging ~ 2.0 days. Further, excretion remained quantifiable for 14 days, providing a long period during which the date of last consumption might be determined. We conclude that inclusion of 15 mg ACZ as a dosage form adherence marker excipient, provides a reliable and sensitive mechanism to confirm medication consumption and detect nonadherence during clinical efficacy trials.
Triskelion‐Shaped π‐Luminophores Bearing Coumarin: Syntheses, Structures, and Luminescence Properties
Authors: Ueda Masafumi , Kokubun Mirai , Mazaki Yasuhiro 
Published: June 2020

AbstractTriskelion‐shaped π‐luminophores bearing three coumarin units 1 a and 1 b were successfully synthesized by the intramolecular Ullmann coupling reaction of triphenyl benzene‐1,3,5‐tricarboxylate derivatives. X‐ray crystal structure analysis revealed that compound 1 adopts a unique curved and three‐blade propeller‐shaped structure. These crystals are a racemic mixture consisting of PPP‐ and MMM‐1 due to the helicity resulting from the steric hindrance. A computational study suggests that this helical inversion process between PPP‐ and MMM‐1 a occurs with comparative ease. The emission spectra of 1 a and 1 b in THF solution showed sharp emission bands at 454 nm and 492 nm, respectively. The Stokes shifts were relatively large at 7385 cm−1 and 6556 cm−1 due to their degenerate frontier molecular orbitals. A solution of 1 b in different organic solvents demonstrated solvatofluorochromism due to intramolecular charge transfer of the coumarin unit in the excited states. Interestingly, both triskelion‐shaped molecules formed aggregates in a mixture of THF‐H2O and exhibited aggregation‐induced emission enhancement characteristics.
Photon Transport and Hydrodynamics in Gas‐Liquid Flows Part 1: Characterization of Taylor Flow in a Photo Microreactor
Authors: Roibu Anca , Van Gerven Tom , Kuhn Simon 
Published: June 2020

AbstractGas‐liquid photoreactions are increasingly implemented in microreactors. Taylor flows containing an inert dispersed phase were previously used to increase the conversion of photochemical reactions in comparison to using a single liquid phase. However, identifying the optimal flow conditions requires an extensive experimental effort. This work aims to understand the photon transport and hydrodynamics in a Taylor flow photo microreactor so that the reactor behavior can be understood and predicted. Chemical actinometry, flow imaging and residence time distribution experiments were used to develop a multi‐region photochemical reaction model. This model shows that the conversion is significantly affected by the liquid distribution, and not by the light scattering or liquid mixing. Moreover, an empirical relation was proposed to predict the optical pathlength in gas‐liquid flows. The knowledge gained in this study helps to optimize the performance of Taylor flow photo microreactors, but also to design improved multiphase flow photochemical systems.
Photon Transport and Hydrodynamics in Gas‐Liquid Flow Part 2: Characterization of Bubbly Flow in an Advanced‐Flow Reactor
Authors: Roibu Anca , Horn Clemens R. , Van Gerven Tom , Kuhn Simon 
Published: June 2020

AbstractThe Corning® G1 Advanced‐Flow™ Reactor (G1 AFR) is a commercially available meso‐scale reactor which promotes a bubbly flow regime and was previously used to scale‐up gas‐liquid photoreactions. In this paper, we study how the photon transport and hydrodynamics affects the performance of G1 AFR in gas‐liquid flow. This was realized by analyzing the flow pattern, liquid residence time, photon flux per liquid volume and optical pathlength using image analysis, residence time distribution (RTD) experiments and chemical actinometry. While the gas content did not significantly influence the RTD responses and photon flux per liquid volume, it affected the liquid residence time and optical pathlength. An empirical correlation was proposed to predict the optical pathlength in gas‐liquid flow. The constant photon flux per liquid volume and hydrodynamics found for bubbly flow in G1 AFR translate into high flexibility to choose the flow conditions without affecting the performance of this photoreactor.