bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineered citrate synthase improves citramalic acid generation in Escherichia coli
Authors: Wu Xianghao , Tovilla‐Coutiño D. Brisbane , Eiteman Mark A.
Published: June 2020

The 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

The 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 study

Papillary 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

Comprehensive 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

Elimination 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.
Career Adaptability and Turnover Intention: A Dual‐Mediation Model
Authors: Dong Bowen , Zheng Boyang , Wang Zhongming
Published: June 2020

Career adaptability denotes psychosocial resources that help employees self‐manage career change through both adapting themselves to the environment and adapting the environment to themselves. Previous studies have probed the former strategy and proposed a negative relationship between career adaptability and turnover intention. However, the presence of the latter strategy suggests a more complex relationship than previously thought. From a person‐job fit perspective, the authors used structural equation modeling to examine the mechanism underlying the relationship between career adaptability and job satisfaction (an important predictor of turnover intention) among 218 employees working in China. The results showed that career adaptability had mixed effects on job satisfaction through the mediating role of task adaptivity and perceived overqualification. Overall, these findings carry theoretical and practical implications for career adaptability research and career counseling practices related to employee development.
Toward Trauma‐Informed Career Counseling
Authors: Powers Janis J. , Duys David
Published: June 2020

The Adverse Childhood Experiences study (Felitti et al., 1998) showed that early adversity can have a profound lifelong effect on personal development, social relationships, coping methods, and career trajectories. The authors review critical findings related to trauma‐informed counseling practices, discuss literature linking trauma and career theories, and consider how career counseling could address the effects of adverse childhood experiences using trauma‐informed practices. An integration of trauma‐informed practices with career counseling using narrative and other approaches is proposed. The proposed integration holds implications for incorporating trauma‐informed practice in career counselor preparation programs and in career counseling practice.
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

Background

The 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.

Methods

Data 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.

Results

Of 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).

Conclusions

Obese men undergoing RP at several Veterans Affairs hospitals were found to be at an increased risk of PCSM, regardless of race.
Induction chemotherapy is the best timekeeper in nasopharyngeal carcinoma
Authors: Cavalieri Stefano , Licitra Lisa
Published: June 2020

NPC‐0501 has shown that induction chemotherapy provides a survival benefit for patients with locoregionally advanced nasopharyngeal carcinoma and has added evidence to current knowledge. In the intensity‐modulated radiotherapy era, neoadjuvant chemotherapy should be considered at least for patients with high‐risk disease.
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

Background

The 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.

Methods

Drug 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.

Results

Osimertinib 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.

Conclusions

These 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

Triskelion‐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

Gas‐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

The 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.
Climate inaction and managerial sensemaking: The case of renewable energy
Authors: Busch Timo , Richert Marcel , Johnson Matthew , Lundie Sven
Published: June 2020

While business responses to climate change have been well researched on the organizational and institutional levels, the corporate strategic behavior on the microlevel—that ranges from proactivity to climate inaction—remain under‐researched. This article explores the individual determinants that affect the sensemaking phases, scanning, interpretation, and action, concerning the installation of on‐site renewable energy technologies. We investigate the extent to which managerial sensemaking is affected by different perceptions, motives, and skills in relation to renewable energy. By doing so, we uncover the individual determinants that affect decisions to either accept or reject the installation of renewable energy technologies. We contribute to the literature on business responses to climate change by deriving several key individual determinants on the microlevel, including technological expertise, sustainability orientation, time perspective, and economic growth attitude, which affect managers' sensemaking. Thus, we offer a framework to illustrate how these individual characteristics can lead either to proactive business responses or conversely to climate inaction.
Tracing Implications of Transnational Policy in Curriculum Events
Authors: Wahlström Ninni
Published: June 2020

The purpose of this keynote address is to discuss how curriculum theory can make a specific contribution to research on transnational education policy; in particular, curriculum theory has implications for national policy due to the interest in exploring educational phenomena at different levels of the school system. From a Swedish perspective on curriculum theory, the coordinative transnational policy ideas of having ‘high expectations’ and ‘raising standards’ are traced through three levels of analysis: the transnational/national societal arena, the programmatic curriculum arena and the classroom/teaching arena. The transnational policy idea of ‘international standards’ underpins the idea of standards‐based curricula, with a focus on the need to reach certain standards of knowledge and obtain equity in assessment; accordingly, such objectives have certain implications for curriculum structure and content as well as for actual teaching in the classroom. At each level of analysis, some concepts are introduced because of their potential to contribute in both exploratory and clarificatory ways. The analysis indicates that there is a need to uphold the role of the curriculum as a framework for genuine educational standards, with the professional teacher serving as the main actor for building educational relationships; otherwise, there is a risk that curriculum standards will degenerate into the instrumental standardisation of knowledge and teaching.
Analysis of bitter orange dietary supplements for natural and synthetic phenethylamines by LC–MS/MS
Authors: Pawar Rahul S. , Sagi Satyanarayanaraju , Leontyev Dmitry
Published: June 2020

Citrus aurantium, commonly known as bitter orange, is a popular dietary supplement ingredient sold worldwide. Bitter orange supplements are sold primarily as weight management and sports performance products and have gained popularity after Ephedra products were banned from the US market. Supplements containing synephrine are reported to exhibit adverse cardiovascular effects especially in the presence of caffeine. In this study, an LC–MS/MS method was established to quantify five natural amines (synephrine, octopamine, tyramine, N‐methyltyramine, and hordenine) and four synthetic phenethylamines (phenylephrine, methylsynephrine, etilefrine, and isopropyloctopamine) in dietary supplements sold in the US. The method was validated and found to have acceptable performance to accurately measure analytes in complex botanical products. The average recoveries from a blank matrix were 88–125% with an RSD of 0.5–7.0%. Fifty‐nine products labeled to contain bitter orange peel, extract, or its amines were purchased and their amine content was measured. Several products were found to contain higher amounts of amines than that expected from a typical bitter orange extract. Of the 23 products that made label claims for synephrine, only 5 products (22%) were within 80–120% of labeled synephrine content. The presence of synthetic amines, methylsynephrine (up to 240 mg/daily serving), and isopropyloctopamine (up to 76 mg/daily serving), whose effects in humans are not known, were detected in six products and one product, respectively. While the use of methylsynephrine and isopropyloctopamine are not permitted in dietary supplements, hordenine, N‐methyltyramine, and octopamine are currently listed on the FDA's Dietary Supplement Ingredient Advisory List.
Fluctuations in hematological athlete biological passport biomarkers in relation to the menstrual cycle
Authors: Mullen Jenny , Bækken Lasse , Bergström Helena , Björkhem Bergman Linda , Ericsson Magnus , Ekström Lena
Published: June 2020

The interpretation of athlete biological passport (ABP) is strengthened by understanding the natural fluctuations in its biological parameters. Here we have assessed the influence of the menstrual cycle on the hematological module of the ABP.

Seventeen women with regular menses were included. Blood samples were collected once a week for two consecutive cycles and analyzed for hematological parameters. Menstrual phases were hormonally determined.

The intra‐individual variation in the hematological parameters was similar between the two cycles. Reticulocyte percentage was significantly lower in the follicle phase (median 0.95%) than in the ovulatory (median 1.10%) and luteal phases (median 1.16%), P = 0.006, whereas no differences were found in hemoglobin concentration, hematocrit, red blood cell count, or red blood cell indices. When the values were entered into the ABP model, findings outside the program‐calculated individual thresholds were identified in two participants. One woman showed an atypical low OFF‐score in the last sample collected, mainly because of increased reticulocyte percentage. This was likely a response to treated insufficient iron stores. One woman displayed an atypical hemoglobin value at the lower limit 2 weeks after ovulation, which was likely due to fluctuations in plasma volume.

In conclusion, the ABP parameters in general are stable throughout the menstrual cycle. Significant differences between the menstrual phases were found in reticulocytes; however, the variation was not related to findings outside the individual thresholds, except in one individual. Moreover, our results highlight the importance of having information about iron supplementation available when evaluating hematological passports.
Non‐native species have multiple abundance–impact curves
Authors: Strayer David L.
Published: June 2020

The abundance–impact curve is helpful for understanding and managing the impacts of non‐native species. Abundance–impact curves can have a wide range of shapes (e.g., linear, threshold, sigmoid), each with its own implications for scientific understanding and management. Sometimes, the abundance–impact curve has been viewed as a property of the species, with a single curve for a species. I argue that the abundance–impact curve is determined jointly by a non‐native species and the ecosystem it invades, so that a species may have multiple abundance–impact curves. Models of the impacts of the invasive mussel Dreissena show how a single species can have multiple, noninterchangeable abundance–impact curves. To the extent that ecosystem characteristics determine the abundance–impact curve, abundance–impact curves based on horizontal designs (space‐for‐time substitution) may be misleading and should be used with great caution, it at all. It is important for scientists and managers to correctly specify the abundance–impact curve when considering the impacts of non‐native species. Diverting attention from the invading species to the invaded ecosystem, and especially to the interaction between species and ecosystem, could improve our understanding of how non‐native species affect ecosystems and reduce uncertainty around the effects of management of populations of non‐native species.
High predictability of direct competition between marine diatoms under different temperatures and nutrient states
Authors: Siegel Philipp , Baker Kirralee G. , Low‐Décarie Etienne , Geider Richard J.
Published: June 2020

The distribution of marine phytoplankton will shift alongside changes in marine environments, leading to altered species frequencies and community composition. An understanding of the response of mixed populations to abiotic changes is required to adequately predict how environmental change may affect the future composition of phytoplankton communities. This study investigated the growth and competitive ability of two marine diatoms, Phaeodactylum tricornutum and Thalassiosira pseudonana, along a temperature gradient (9–35°C) spanning the thermal niches of both species under both high‐nitrogen nutrient‐replete and low‐nitrogen nutrient‐limited conditions. Across this temperature gradient, the competitive outcome under both nutrient conditions at any assay temperature, and the critical temperature at which competitive advantage shifted from one species to the other, was well predicted by the temperature dependencies of the growth rates of the two species measured in monocultures. The temperature at which the competitive advantage switched from P. tricornutum to T. pseudonana increased from 18.8°C under replete conditions to 25.3°C under nutrient‐limited conditions. Thus, P. tricornutum was a better competitor over a wider temperature range in a low N environment. Being able to determine the competitive outcomes from physiological responses of single species to environmental changes has the potential to significantly improve the predictive power of phytoplankton spatial distribution and community composition models.
Land masses and oceanic currents drive population structure of Heritiera littoralis, a widespread mangrove in the Indo‐West Pacific
Authors: Banerjee Achyut Kumar , Guo Wuxia , Qiao Sitan , Li Weixi , Xing Fen , Lin Yuting , Hou Zhuangwei , Li Sen , Liu Ying , Huang Yelin
Published: June 2020

Phylogeographic forces driving evolution of sea‐dispersed plants are often influenced by regional and species characteristics, although not yet deciphered at a large spatial scale for many taxa like the mangrove species Heritiera littoralis. This study aimed to assess geographic distribution of genetic variation of this widespread mangrove in the Indo‐West Pacific region and identify the phylogeographic factors influencing its present‐day distribution. Analysis of five chloroplast DNA fragments’ sequences from 37 populations revealed low genetic diversity at the population level and strong genetic structure of H. littoralis in this region. The estimated divergence times between the major genetic lineages indicated that glacial level changes during the Pleistocene epoch induced strong genetic differentiation across the Indian and Pacific Oceans. In comparison to the strong genetic break imposed by the Sunda Shelf toward splitting the lineages of the Indian and Pacific Oceans, the genetic differentiation between Indo‐Malesia and Australasia was not so prominent. Long‐distance dispersal ability of H. littoralis propagules helped the species to attain transoceanic distribution not only across South East Asia and Australia, but also across the Indian Ocean to East Africa. However, oceanic circulation pattern in the South China Sea was found to act as a barrier creating further intraoceanic genetic differentiation. Overall, phylogeographic analysis in this study revealed that glacial vicariance had profound influence on population differentiation in H. littoralis and caused low genetic diversity except for the refugia populations near the equator which might have persisted through glacial maxima. With increasing loss of suitable habitats due to anthropogenic activities, these findings therefore emphasize the urgent need for conservation actions for all populations throughout the distribution range of H. littoralis.
Dibenzotropylidene Substituted Ligands for Early Main Group Metal‐Alkene Bonding
Authors: Martin Johannes , Langer Jens , Wiesinger Michael , Elsen Holger , Harder Sjoerd
Published: June 2020

New N‐ligands with TROP‐substituents are introduced (TROP = [5H]dibenzo[a,d]cyclohepten‐5‐yl): (TROP)(DIPP)N (DIPP = 2,6‐diisopropylphenyl), TROPBDI (HC[C(Me)N‐TROP]2) and the β‐diketiminate ligand TROP–DIPPBDI with TROP and DIPP substituents at N. Several Li, Mg, Ca and Zn complexes with these ligands have been isolated and were characterized by X‐ray diffraction. While TROP‐substituents in the protonated ligands show endo‐exo exchange, TROP‐substituents in the metal complexes are in endo‐conformation due to metal···alkene bonding. Short contacts between the metal and the TROP alkene unit are observed and some of these are the shortest reported; (TROPBDI)Li: Li···C 2.416(3) Å, [(TROP)(DIPP)N]2Ca: Ca···C 2.742(2) Å. TROPBDI shows superior metal shielding properties to the Li complex with a buried volume of VB = 78.7 %. DFT calculations on [(TROP)(DIPP)N]2Mg show a minimum with asymmetric Mg···alkene bonding. Symmetric Mg···alkene bonding is a transition state 1.9 kcal/mol higher in energy. Asymmetry in alkene‐Mg bonding is explained by an ion‐induced polarization of the C=C bond and electrostatic Mg2+···(δ‐)C=C(δ+) attraction. The TROP‐substituent stabilizes low valent radical species but attempts to isolate (TROPBDI)Mg· or (TROPBDI)Zn· by reduction of the iodide precursors failed. Intensely black coloured raw products hint towards formation of radical species. Several radical decomposition products have been structurally characterized.
One‐Electron Reduction of Redox‐Active Esters to Generate Carbon‐Centered Radicals
Authors: Niu Pengfei , Li Jun , Zhang Yongxin , Huo Congde
Published: June 2020

The one‐electron reduction (OER) can profoundly affect the structure and reactivity of organic compounds. OER induced radical decarboxylative functionalizations of redox‐active esters have gained wide concerns in this century. In this review, we present recent advances using redox‐active esters as carbon‐centered radical precursors to form carbon–carbon and carbon–heteroatom bonds.
Hydrogen Fuel Cell Vehicle Development in China: An Industry Chain Perspective
Authors: Zhao Fuquan , Mu Zhexuan , Hao Han , Liu Zongwei , He Xin , Victor Przesmitzki Steven , Ahmad Amer Amer
Published: June 2020

Hydrogen fuel cell vehicle (FCV) technology has significant implications on energy security and environmental protection. In the past decade, China has made great progress in the hydrogen and FCV industry considering both the government's policy issuances and enterprises’ production. However, there are still some technological and cost challenges obstructing the commercialization of FCVs. Herein, the status of China's hydrogen FCV industry is analyzed comprehensively from three perspectives: policy support, market application, and technology readiness level. The unique characteristics and key issues in each part of the industry chain are emphasized. Furthermore, the energy, environmental, and economic performances of FCV in the life‐cycle perspective are reviewed and summarized based on pre‐existing literature and reports. The life‐cycle analysis of hydrogen and FCV indicates that the energy and environmental impacts of FCVs are highly related to the sources of hydrogen. With the combination of industry status and technology performances, it is highlighted that technology advancements in hydrogen production and fuel cells and the optimization of the manufacturing processes for fuel cell systems are equally essential in the development of hydrogen FCVs.
Dynamics and seismic performance of rocking bridges accounting for the abutment‐backfill contribution
Authors: Thomaidis Ioannis M. , Kappos Andreas J. , Camara Alfredo
Published: June 2020

The present study explores analytically the concept of rocking isolation in bridges considering for the first time the influence of the abutment‐backfill system. The dynamic response of rocking bridges with free‐standing piers of same height and same section is examined assuming negligible deformation for the substructure and the superstructure. New relationships for the prediction of the bridge rocking motion are derived, including the equation of motion and the restitution coefficient at each impact at the rocking interfaces. The bridge structure is found to be susceptible to a failure mode related to the failure of the abutment‐backfill system, which can occur prior to the well‐known overturning of the rocking piers. Thus, a new failure spectrum is proposed called Failure Minimum Acceleration Spectrum (FMAS) which extends the overturning spectrum put forward in previous studies, and it differs in principle from the latter. The comparison with the dynamic response of bridges modelled as rocking frames without abutments reveals not only that seat‐type abutments and their backfill have a generally beneficial effect on the seismic performance of rocking pier bridges by suppressing the free rocking motion of the frame system, but also that the simple frame model cannot capture all salient features of the rocking bridge response as it misses potential failure modes, overestimating the rocking bridge's safety when these modes are critical.
Comparison of Alternative Methods for Bioaccumulation Assessment: Scope and Limitations of In Vitro Depletion Assays with Rainbow Trout and Bioconcentration Tests in the Freshwater Amphipod Hyalella azteca
Authors: Kosfeld Verena , Fu Qiuguo , Ebersbach Ina , Esser Dana , Schauerte Anna , Bischof Ina , Hollender Juliane , Schlechtriem Christian
Published: June 2020

Bioaccumulation assessment predominantly relies on the bioconcentration factor (BCF) as the sole decisive metric. The test guideline 305 by the Organisation for Economic Co-operation and Development (OECD) provides the standard procedure for deriving this in vivo fish BCF, which is not only expensive and labor-intensive, but also requires many animals. Accordingly, there is a great need for and interest in alternative methods that can help to reduce, replace, and refine vertebrate tests, as described in the 3R principles. Two alternative approaches have been developed: the bioconcentration test with the freshwater amphipod Hyalella azteca and the OECD test guideline 319 which provides a method to determine experimentally derived in vitro metabolism rates that can then be incorporated into in silico prediction models for rainbow trout BCF calculation. In the present study both alternative methods were applied to 5 substances of different physicochemical characteristics. The results were compared with literature values of fish in vivo BCFs and additional BCFs obtained with the alternative methods, if available. Potential differences between the results of the test methods are discussed utilizing information such as in vivo metabolism rates. The currently available data set suggests that these 2 alternative methods pose promising alternatives to predict bioaccumulation in fish, although defined applicability domains have yet to be determined. Environ Toxicol Chem 2020;39:1813–1825. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC
Flavor, antimicrobial activity, and physical properties of composite film prepared with different surfactants
Authors: Li Xin , Tu Zong‐Cai , Sha Xiao‐Mei , Ye Yun‐Hua , Li Zhong‐Ying
Published: June 2020

Different surfactants (lecithin, Tween‐20, and Tween‐80) were added in composite film during the preparation. Flavor, antimicrobial activity, and physical properties of ginger essential oil ‐gelatin film were investigated, in order to study the effect of surfactants on the properties of film. The flavor of GEO was not detected in the film prepared with Tween‐20 and film prepared with Tween‐80, and these two films exhibited stronger antimicrobial activity; film prepared with lecithin possessed higher value in thickness, elongation at break, water solubility, ΔE and opacity, lower value in water vapor property, and tensile strength; attenuated total reflectance‐Fourier transform infrared spectrum results suggested, Tween‐20 and Tween‐80 enhanced the strength of covalent bond, and lecithin weakened the strength of hydrogen bond; and the result of scanning electron microscope showed that Tween‐20 and Tween‐80 improved the dispersion of oil droplets in film. Therefore, this study suggested that surfactants had an influence on the physical properties and molecular structure of a resulting film; in addition, Tween‐20 and Tween‐80 could reduce the flavor of GEO in film, improving the antimicrobial activity of film.
Mental health among otolaryngology resident and attending physicians during theCOVID‐19 pandemic: National study
Authors: Civantos Alyssa M. , Byrnes Yasmeen , Chang Changgee , Prasad Aman , Chorath Kevin , Poonia Seerat K. , Jenks Carolyn M. , Bur Andrés M. , Thakkar Punam , Graboyes Evan M. , Seth Rahul , Trosman Samuel , Wong Anni , Laitman Benjamin M. , Harris Brianna N. , Shah Janki , Stubbs Vanessa , Choby Garret , Long Qi , Rassekh Christopher H. , Thaler Erica , Rajasekaran Karthik
Published: June 2020

Background

Otolaryngologists are among the highest risk for COVID‐19 exposure.

Methods

This is a cross‐sectional, survey‐based, national study evaluating academic otolaryngologists. Burnout, anxiety, distress, and depression were assessed by the single‐item Mini‐Z Burnout Assessment, 7‐item Generalized Anxiety Disorder Scale, 15‐item Impact of Event Scale, and 2‐item Patient Health Questionnaire, respectively.

Results

A total of 349 physicians completed the survey. Of them, 165 (47.3%) were residents and 212 (60.7%) were males. Anxiety, distress, burnout, and depression were reported in 167 (47.9%), 210 (60.2%), 76 (21.8%), and 37 (10.6%) physicians, respectively. Attendings had decreased burnout relative to residents (odds ratio [OR] 0.28, confidence interval [CI] [0.11‐0.68];P= .005). Females had increased burnout (OR 1.93, CI [1.12.‐3.32];P= .018), anxiety (OR 2.53, CI [1.59‐4.02];P< .005), and distress (OR 2.68, CI [1.64‐4.37];P< .005). Physicians in states with greater than 20 000 positive cases had increased distress (OR 2.01, CI [1.22‐3.31];P= .006).

Conclusion

During the COVID‐19 pandemic, the prevalence of burnout, anxiety, and distress is high among academic otolaryngologists.
Universal screening for SARS‐CoV‐2 in asymptomatic obstetric patients in Tokyo, Japan
Authors: Ochiai Daigo , Kasuga Yoshifumi , Iida Miho , Ikenoue Satoru , Tanaka Mamoru
Published: June 2020

The prevalence of COVID‐19 in asymptomatic obstetric patients in Tokyo was shown to be 4% when universal screening was implemented. Physicians should pay attention to asymptomatic patients to prevent nosocomial infections.
The impact of oral exposure to low‐dose tris(2‐butoxyethyl) phosphate in allergic asthmatic mice
Authors: Yanagisawa Rie , Koike Eiko , Win‐Shwe Tin‐Tin , Kawaguchi Maiko , Takano Hirohisa
Published: June 2020

Tris(2‐butoxyethyl) phosphate (TBEP) is a major organophosphorus flame retardant and has been widely increasing as a substitute for brominated flame retardants. TBEP may have adverse effects on human health; however, its impact on immune and allergic responses remains largely uncharacterized. In this study, the effects of low‐dose TBEP comparable with the level of actual human exposure to that of human tolerable daily intake on allergic asthmatic mice were explored. Five‐week‐old C3H/HeJSlc male mice consumed a diet containing approximately 0.02, 0.2 or 2 μg/kg/day TBEP and were intratracheally administrated ovalbumin (OVA) (1 μg/mouse every 2 weeks from 5 to 11 weeks of age). Exposure to 2 μg/kg/day TBEP with OVA tended to enhance allergic pulmonary inflammation and significantly elevated mRNA levels of interleukin‐5, eotaxin‐1 and estrogen receptor alpha (ERα) compared with OVA alone. In mediastinal lymph nodes (MLNs), TBEP (0.2 or 2 μg/kg/day) with OVA significantly increased in total cell number and promoted conventional dendritic cell activation than OVA alone; MLN cell proliferation by OVA restimulation was also enhanced in these groups. In the bone marrow (BM), TBEP (0.02 or 0.2 μg/kg/day) with OVA resulted in a net decrease in total cell number and fraction of CCR2+Gr‐1+ cells; the fraction of Gr‐1+ cells increased. In conclusion, oral exposure to low‐dose TBEP levels equivalent to tolerable daily intake may exacerbate allergic pulmonary inflammation by promoting a skewed T‐helper 2 cell response, upregulation of ERα and dysregulation of both MLN and BM microenvironments.
Biological applications study of bio‐nanocomposites based on chitosan/TiO2 nanoparticles polymeric films modified by oleic acid
Authors: Hanafy Magda S. , Desoky Waled M. , Hussein Elham M. , El‐Shaer Nahla H. , Gomaa Mohamed , Gamal Amira A. , Esawy Mona A. , Guirguis Osiris W.
Published: June 2020

The aim of the present study was to prepare and characterize nanocomposite films to improve the treatment of skin wounds by applying the film as a bandage. To modify chitosan (Cs) and to prepare nanocomposites, a mixture between titanium dioxide nanoparticles (TiO2NPs) was performed at different concentrations (2, 5, 10 and 15 wt%) and oleic acid (OA). The thin nanocomposite films were prepared by using casting method. The prepared films (Cs, Cs/TiO2NPs, Cs/OA and Cs/OA/TiO2NPs) were described by water absorption (swelling study) and biological degradation. Physico‐chemical characterizations of Cs, Cs/OA, Cs/TiO2NPs and Cs/OA/TiO2NPs (with only 15 wt% TiO2NPs) films were determined by X‐ray diffraction, transmission high‐resolution electron microscopy, field emission scanning electron microscopy, thermal analysis and Fourier transform infrared spectroscopy as well as their mechanical properties. Antimicrobial activity against microorganisms has been studied to assess activity against bacteria. The prepared nanocomposite films showed good antimicrobial activity for both Gram‐positive and Gram‐negative bacteria. The therapeutic effects of Cs‐TiO2NPs‐oleic acid nanocomposites on healing excision wounds were studied in rat animal model. The data obtained revealed that groups treated with nanocomposites showed enhancement wound closure and speed up wound healing time.
PyCDFT: A Python package for constrained density functional theory
Authors: Ma He , Wang Wennie , Kim Siyoung , Cheng Man‐Hin , Govoni Marco , Galli Giulia
Published: June 2020

We present PyCDFT, a Python package to compute diabatic states using constrained density functional theory (CDFT). PyCDFT provides an object‐oriented, customizable implementation of CDFT, and allows for both single‐point self‐consistent‐field calculations and geometry optimizations. PyCDFT is designed to interface with existing density functional theory (DFT) codes to perform CDFT calculations where constraint potentials are added to the Kohn–Sham Hamiltonian. Here, we demonstrate the use of PyCDFT by performing calculations with a massively parallel first‐principles molecular dynamics code, Qbox, and we benchmark its accuracy by computing the electronic coupling between diabatic states for a set of organic molecules. We show that PyCDFT yields results in agreement with existing implementations and is a robust and flexible package for performing CDFT calculations. The program is available at https://dx.doi.org/10.5281/zenodo.3821097.
Fabrication of Ag‐photodeposited TiO2/cordierite honeycomb monolith photoreactors for 2‐naphthol degradation
Authors: Vo Ngoc‐Quoc‐Duy , Huynh Ngoc‐Diem‐Trinh , Le Minh‐Vien , Vo Kieu‐Duyen , Vo Dai‐Viet N
Published: June 2020

BACKGROUND

Polycyclic aromatic hydrocarbons and their derivatives have harmful effects on organisms and the environment. As a typical polycyclic aromatic hydrocarbon, 2‐naphthol is a persistent, highly toxic organic pollutant that biodegrades very slowly and thus its elimination is of high priority.

RESULTS

Ag‐deposited TiO2/cordierite honeycomb monoliths (CHMs) have been successfully applied to the photocatalytic degradation of 2‐naphthol. The physical properties of the catalyst were characterized using various techniques. Deposition of metallic silver on a thin layer of TiO2 adhering to the inner walls of the CHM reduces the bandgap energy and lowers the recombination rate of photogenerated electrons and holes. The optimal photocatalyst (0.4Ag‐deposited S700‐ST) exhibits a first‐order degradation rate of k = 0.048 min−1 with 91.0% decomposition of 2‐naphthol after 240 min of irradiation with 12 W, 395 nm LED light. The 0.4Ag‐deposited S700‐ST material is stable throughout four photocatalytic reaction cycles.

CONCLUSIONS

The work presented describes the development of a robust, stable TiO2‐coated CHM that overcomes the recovery drawbacks of nano‐TiO2‐based slurries in photocatalytic wastewater treatment. © 2020 Society of Chemical Industry