bluuebunny/crossref_metadata_2025 huggingface dataset:
The combined effects of light intensity, temperature, and water potential on wall deposition in regulating hypocotyl elongation of Brassica rapa
Authors: Wang Hongfei , Shang Qingmao
Published: May 2020

Hypocotyl elongation is a critical sign of seed germination and seedling growth, and it is regulated by multi-environmental factors. Light, temperature, and water potential are the major environmental stimuli, and their regulatory mechanism on hypocotyl growth has been extensively studied at molecular level. However, the converged point in signaling process of light, temperature, and water potential on modulating hypocotyl elongation is still unclear. In the present study, we found cell wall was the co-target of the three environmental factors in regulating hypocotyl elongation by analyzing the extension kinetics of hypocotyl and the changes in hypocotyl cell wall of Brassica rapa under the combined effects of light intensity, temperature, and water potential. The three environmental factors regulated hypocotyl cell elongation both in isolation and in combination. Cell walls thickened, maintained, or thinned depending on growth conditions and developmental stages during hypocotyl elongation. Further analysis revealed that the imbalance in wall deposition and hypocotyl elongation led to dynamic changes in wall thickness. Low light repressed wall deposition by influencing the accumulation of cellulose, hemicellulose, and pectin; high temperature and high water potential had significant effects on pectin accumulation overall. It was concluded that wall deposition was tightly controlled during hypocotyl elongation, and low light, high temperature, and high water potential promoted hypocotyl elongation by repressing wall deposition, especially the deposition of pectin.
The combined impacts of wheat spatial position and phenology on cereal aphid abundance
Authors: Batyrshina Zhaniya S. , Cna’ani Alon , Rozenberg Tamir , Seifan Merav , Tzin Vered
Published: May 2020

Background

Wheat is a staple crop that suffers from massive yield losses caused by cereal aphids. Many factors can determine the abundance of cereal aphids and the damage they cause to plants; among them are the plant’s genetic background, as well as environmental conditions such as spatial position within the plot, the composition and the distance from neighboring vegetation. Although the effects of these factors have been under scrutiny for many years, the combined effect of both factors on aphid populations is not fully understood. The goal of this study was to examine the collective impact of genotype and environment on wheat phenology (developmental stages), chemical diversity (metabolites), and insect susceptibility, as manifested by cereal aphid abundance.

Methods

To determine the influence of plant genotype on the metrics mentioned above, we measured the phenology, chemical profile, and aphid abundance of four wheat genotypes, including the tetraploid wild emmer (Triticum turgidum ssp. dicoccoides cv. Zavitan), tetraploid durum (Triticum turgidum ssp. durum cv. Svevo), and two hexaploid spring bread (Triticum aestivum), ‘Rotem’ and ‘Chinese Spring’. These genotypes are referred to as “focal” plants. To evaluate the impact of the environment, we scored the distance of each focal plant (spatial position) from two neighboring vegetation types: (i) natural resource and (ii) monoculture wheat resource.

Results

The results demonstrated that the wild emmer wheat was the most aphid-resistant, while the bread wheat Rotem was most aphid-susceptible. Aphids were more abundant in plants that matured early. The spatial position analysis demonstrated that aphids were more abundant in focal plants located closer to the margin monoculture wheat resource rather than to the natural resource, suggesting a resource concentration effect. The analysis of metabolic diversity showed that the levels of three specialized metabolites from the flavonoid class, differed between the wheat genotypes and some minor changes in central metabolites were shown as well. Altogether, these results demonstrate a combined effect of genetic background and spatial position on wheat phenology and aphid abundance on plants. This exposes the potential role of the marginal vegetation environment in shaping the insect population of desirable crops. These findings highlight the importance of maintaining plant intra-specific variation in the agriculture system because of its potential applications in reducing pest density.
Effects of mining on the molybdenum absorption and translocation of plants in the Luanchuan molybdenum mine
Authors: Yin Kejing , Shi Zhaoyong , Zhang Mengge , Li Yajuan
Published: May 2020

Background

There is a critical need to examine whether mining of molybdenum (Mo) ore will affect Mo absorption and translocation by plants at a community level.

Methods

Indigenous plants and their rhizospheric soil (0–20 cm) growing in two different areas including the mining and the unexploited areas were collected from the Luanchuan Mo mine—one of the largest Mo mines in Asia. The concentrations of Mo and other heavy metals of plants or soil were measured by ICP-AES. Mo absorption and translocation in plants growing in two areas were investigated and compared. Heavy metal pollution in soil was also evaluated by the potential ecological hazard index method.

Results

Mo concentration in mining soils was higher with the changes from 108.13 to 268.13 mg kg−1 compared to unexploited area. Mo concentrations in shoots and roots of plants growing in the mining area were also significant higher than those growing in the unexploited area with 2.59 and 2.99 times, respectively. The Mo translocation factor of plants growing in the unexploited area was 1.61, which reached 1.69 times that of plants growing in the mining area. Mo was the main heavy metal pollutant in the soil of both the mining and the unexploited areas.

Conclusion

Mining of Mo had changed not only the Mo concentration in soil but also Mo absorption and translocation in plants. Plants growing in the mining area absorbed more Mo from the soil but translocated relatively less to shoots than plants of the unexploited area. However, the mechanisms of Mo absorption and translocation of plants in mining area should be further studied in the future.
Aspects of Modern Systemic Approach (I): Beyond the Dynamic Systems Definition, Structure and Properties
Authors: Cioruța Bogdan , Coman Mirela , Lauran Alexandru
Published: May 2020

General Systems Theory, as well as Systems Theory - as integrated part of the first one, are still under the scrutiny of researchers, either through the interest shown for micro-systems or for macro-systems, as derivatives of the system.

In accordance with the research undertaken in either of the two ends of the reference range for the system - as a fundamental element of systems theory, our concerns are to familiarize the reader with the diversity of concepts and develpoment stages specific to the two areas of interest - General Systems Theory and Systems Theory. Also, as the objective of the present study, an attempt was made to bring to the fore some definitions and conceputal characterization, respectively with the structure and properties of different system types. At the same tine, are underlined different systemic approaches and representations, along with the position of Systemology in relation to the General Systems Theory and Systems Theory.
The Effects of Parents’ Reactions towards Teenage Pregnancy on Pregnant Teenagers’ Educational Aspirations in Secondary Schools in Buea Sub-division, South West Region of Cameroon
Authors: Tambi Agborbechem Peter , Mesue Edna Emade
Published: May 2020

Teenage pregnancy is regarded as a major socio-medical and socio-economic phenomenon in both developed and developing countries and has become more rampant in recent times. This also happens at the level of schooling. The study investigated the effects of parents’ reactions on teenage pregnancy on their pregnant teenager’s aspirations. A qualitative research paradigm (ethnographic approach) was used in conducting this study. Twenty one parents and twenty four pregnant teenagers participated in the study. A focus group discussion guide, interview guide and observation guide were the instruments used for the collection of data for the study. Data were analyzed with the use of thematic-content analysis and pre-coding. Pregnant teenagers are allowed to continue schooling and given three months maternity leave before the delivery date. The result is psychosocial problems with negative effects on their aspirations. The results show that parents’ reactions have serious consequences on pregnant adolescents’ aspirations. Therefore, most pregnant students leave school before they are given maternity leave and some who go on maternity leave do not return. This is probably because of the way they are treated in school and back at home. They are provoked by school administrators and rejected at home by parents. Counselling should also be done to the parents of the girls as stipulated in the re-entry policy. By so doing, they may be able to support their daughters during the challenging stages of parenthood and take care of their grandchildren.
Nitrogen Transformation in Waterlogged Soil in Indian Rice Fields: A Review
Authors: Parit Rajat Kumar , Bharteey P. K. , Saikia Bishnu Jyoti , Bora Sarat Sekhar , Maurya P. K. , Tabing Ruthy
Published: May 2020

No other element can match the essentiality of nitrogen in soil for growth and development of plants and its transformations among various forms viz., nitrite, nitrate, ammonium are mostly mediated by microbes. As its transformation depends on major microbial activity and thus, there is a huge difference between the transformation of it in aerobic soil and anaerobic soil. This difference mainly arises due to presence and absence of oxygen. The absence of oxygen in soil creates anaerobic condition and thus promotes the growth of anaerobic microbes. In submerged soil, applied nitrogen is lost in various forms such as volatilization, denitrification, leaching and runoff out of which ammonium volatilization causes the maximum loss. The recovery of applied nitrogen, as recorded from various filed experiments in India, has been found to vary from 28 to 34% for submerged rice. The chemistry of nitrogen in submerged soil is quite interesting for this review.
Interlayer Engineering of Molybdenum Trioxide toward High‐Capacity and Stable Sodium Ion Half/Full Batteries
Authors: Wang Bo , Ang Edison Huixiang , Yang Yang , Zhang Yufei , Geng Hongbo , Ye Minghui , Li Cheng Chao
Published: May 2020

Orthorhombic molybdenum trioxide (MoO3) is one of the most promising anode materials for sodium‐ion batteries because of its rich chemistry associated with multiple valence states and intriguing layered structure. However, MoO3 still suffers from the low rate capability and poor cycle induced by pulverization during de/sodiation. An ingenious two‐step synthesis strategy to fine tune the layer structure of MoO3 targeting stable and fast sodium ionic diffusion channels is reported here. By integrating partially reduction and organic molecule intercalation methodologies, the interlayer spacing of MoO3 is remarkably enlarged to 10.40 Å and the layer structural integration are reinforced by dimercapto groups of bismuththiol molecules. Comprehensive characterizations and density functional theory calculations prove that the intercalated bismuththiol (DMcT) molecules substantially enhanced electronic conductivity and effectively shield the electrostatic interaction between Na+ and the MoO3 host by conjugated double bond, resulting in improved Na+ insertion/extraction kinetics. Benefiting from these features, the newly devised layered MoO3 electrode achieves excellent long‐term cycling stability and outstanding rate performance. These achievements are of vital significance for the preparation of sodium‐ion battery anode materials with high‐rate capability and long cycling life using intercalation chemistry.
CRISPR/Cas13a Powered Portable Electrochemiluminescence Chip for Ultrasensitive and Specific MiRNA Detection
Authors: Zhou Ting , Huang Ru , Huang Mengqi , Shen Jinjin , Shan Yuanyue , Xing Da
Published: May 2020

MicroRNAs (miRNAs) have been widely investigated as potential biomarkers for early clinical diagnosis of cancer. Developing an miRNA detection platform with high specificity, sensitivity, and exploitability is always necessary. Electrochemiluminescence (ECL) is an electrogenerated chemiluminescence technology that greatly decreases background noise and improves detection sensitivity. The development of a paper‐based ECL biosensor further makes ECL suitable for point‐of‐care detection. Recently, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a as high‐fidelity, efficient, and programmable CRISPR RNA (crRNA) guided RNase has brought a next‐generation biosensing technology. However, existing CRISPR/Cas13a based detection often faces a trade‐off between sensitivity and specificity. In this research, a CRISPR/Cas13a powered portable ECL chip (PECL‐CRISPR) is constructed. Wherein target miRNA activates Cas13a to cleave a well‐designed preprimer, and triggers the subsequent exponential amplification and ECL detection. Under optimized conditions, a limit‐of‐detection of 1 × 10−15 m for miR‐17 is achieved. Through rationally designing the crRNA, the platform can provide single nucleotide resolution to dramatically distinguish miRNA target from its highly homologous family members. Moreover, the introduction of “light‐switch” molecule [Ru(phen)2dppz]2+ allows the platform to avoid tedious electrode modification and washing processes, thereby simplifying the experimental procedure and lower testing cost. Analysis results of miRNA from tumor cells also demonstrate the PECL‐CRISPR platform holds a promising potential for molecular diagnosis.
Inkjet‐Printed Iontronics for Transparent, Elastic, and Strain‐Insensitive Touch Sensing Matrix
Authors: Gao Dace , Wang Jiangxin , Ai Kaixuan , Xiong Jiaqing , Li Shaohui , Lee Pooi See
Published: May 2020

Next‐generation soft electronics are expected to be intrinsically stretchable, skin conformable, and fully integrated with diverse receptive modules to facilitate bidirectional human–machine interactions. Receptive touch sensors, in particular, should provide stable touch sensing outputs without being affected by external force‐induced strains. Herein, the design and fabrication of an iontronic touch sensing matrix, based on the fringe‐field capacitive mechanism, are introduced for robust touch mapping under large deformation. Enabled by our well‐formulated ink, ionic gel electrodes are directly inkjet printed onto elastomeric substrate to impart superior transparency and elasticity, and hybridized with a customized electronic circuitry through electrical double layers (EDLs) for the multiplexing and transduction of capacitive signals. Notably, the coplanar “interlocking‐diamond” electrode layout in a stretchable modality is adopted for the first time, which helps to boost touch sensitivity and suppress strain‐induced artifacts under static/dynamic deformations. For practical applications, the iontronic matrix demonstrates the capabilities of proximity sensing, multitouch detection, and gesture communication in real time, leading to a robust touch sensing interface that captures high‐fidelity signals during complex human–machine interactions.
A biocultural examination of home food production and child growth in highland Peru
Authors: Hoke Morgan K.
Published: May 2020

Objectives

Chronic malnutrition remains a persistent global health issue. This mixed methods investigation in rural Peru examines the role of home food production (HFP) in reducing child malnutrition by testing the following hypotheses: (a) higher HFP will be associated with higher infant z‐scores than those with less HFP and (b) infants with higher HFP will exhibit improved longitudinal growth outcomes across 6 months.

Methods

Ethnographic methods include semi‐structured interviews and participant observation. A household survey and anthropometric data were collected twice, from 86 infants under of 24 months old. A HFP index (HFI) was generated based on reports of animals for meat consumption, eggs, milk, and agricultural products for home consumption. Kruskal‐Wallis tests were used to examine patterns of HFI and infant anthropometrics. Multivariate regressions were used to examine the relationships between HFP and infant height for age (HAZ), weight for age (WAZ), and triceps skinfold for age (TSAZ) in both rounds and 6‐month change between rounds (6MΔ).

Results

There were no relationships between HFI and infant z‐scores in round one, however, HFI was significantly positively related to HAZ (B = 0.091,P < .039) in round two and with 6MΔin HAZ (B = 0.09,P < .047). HFI did not predict WAZ or TSAZ in either round.

Conclusions

HFP represents an important influence of infant growth in Nuñoa, likely through nutritional improvement due to increased availability of animal‐sourced foods and through contribution to household economy and maternal empowerment.
Methanol Synthesis at a Wide Range of H2/CO2 Ratios over a Rh‐In Bimetallic Catalyst
Authors: Li Molly Meng‐Jung , Zou Hanbo , Zheng Jianwei , Wu Tai‐Sing , Chan Ting‐Shan , Soo Yun‐Liang , Wu Xin‐Ping , Gong Xue‐Qing , Chen Tianyi , Roy Kanak , Held Georg , Tsang Shik Chi Edman
Published: May 2020

There is increasing interest in capturing H2 generated from renewables with CO2 to produce methanol. However, renewable hydrogen production is expensive and in limited quantity compared to CO2. Excess CO2 and limited H2 in the feedstock gas is not favorable for CO2 hydrogenation to methanol, causing low activity and poor methanol selectivity. Now, a class of Rh‐In catalysts with optimal adsorption properties to the intermediates of methanol production is presented. The Rh‐In catalyst can effectively catalyze methanol synthesis but inhibit the reverse water‐gas shift reaction under H2‐deficient gas flow and shows the best competitive methanol productivity under industrially applicable conditions in comparison with reported values. This work demonstrates a strong potential of Rh‐In bimetallic composition, from which a convenient methanol synthesis based on flexible feedstock compositions (such as H2/CO2 from biomass derivatives) with lower energy cost can be established.
Water‐Soluble Polymers with Appending Porphyrins as Bioinspired Catalysts for the Hydrogen Evolution Reaction
Authors: Xie Lisi , Tian Jia , Ouyang Yingjie , Guo Xinai , Zhang Weian , Apfel Ulf‐Peter , Zhang Wei , Cao Rui
Published: May 2020

Molecular design to improve catalyst performance is significant but challenging. In enzymes, residue groups that are close to reaction centers play critical roles in regulating activities. Using this bioinspired strategy, three water‐soluble polymers were designed with appending Co porphyrins and different side‐chain groups to mimic enzyme reaction centers and activity‐controlling residue groups, respectively. With these polymers, high hydrogen evolution efficiency was achieved in neutral aqueous media for electro‐ (turnover frequency >2.3×104 s−1) and photocatalysis (turnover number >2.7×104). Porphyrin units are surrounded and protected by polymer chains, and more importantly, the activity can be tuned with different side‐chain groups. Therefore, instead of revising molecular structures that is difficult from both design and synthesis points of view, polymers can be used to improve molecular solubility and stability and simultaneously regulate activity by using side‐chain groups.
Die Chemie verformbarer poröser Kristalle – Strukturdynamik und Gasadsorptionseigenschaften
Authors: Krause Simon , Hosono Nobuhiko , Kitagawa Susumu
Published: May 2020

In diesem Kurzaufsatz wird die Chemie von verformbaren porösen Kristallen (SPCs) anhand von Struktureigenschaften und deren Auswirkungen auf die Verformbarkeit und den daraus resultierenden Strukturübergang diskutiert. Besonders Eigenschaften, die auf metastabilen Übergangszuständen basieren oder durch lokale dynamische Funktionalität hervorgerufen werden, sind hierbei von Interesse. Unterschiede in den Adsorptionseigenschaften rigider poröser Materialien und denen von SPCs auf Grundlage etablierter thermodynamischer und kinetischer Aspekte zeigen das Anwendungspotenzial dieser Materialien für Adsorptionstechniken auf. Die Charakterisierung dieser Eigenschaften und die daraus resultierenden Phänomene werden dabei in den Mittelpunkt gerückt, und abschließend wird ein Ausblick auf die nächste Generation verformbarer poröser Kristalle gegeben.
A Fullerene‐Based Molecular Torsion Balance for Investigating Noncovalent Interactions at the C60 Surface
Authors: Yamada Michio , Narita Haruna , Maeda Yutaka
Published: May 2020

To investigate the nature and strength of noncovalent interactions at the fullerene surface, molecular torsion balances consisting of C60 and organic moieties connected through a biphenyl linkage were synthesized. NMR and computational studies show that the unimolecular system remains in equilibrium between well‐defined folded and unfolded conformers owing to restricted rotation around the biphenyl C−C bond. The energy differences between the two conformers depend on the substituents and is ascribed to differences in the intramolecular noncovalent interactions between the organic moieties and the fullerene surface. Fullerenes favor interacting with the π‐faces of benzenes bearing electron‐donating substituents. The correlation between the folding free energies and corresponding Hammett constants of the substituents in the arene‐containing torsion balances reflects the contributions of the electrostatic interactions and dispersion force to face‐to‐face arene–fullerene interactions.
Verbesserter Zugang zu organisch löslichen Di‐ und Tetrafluoridochlorat(I/III)‐Salzen
Authors: Pröhm P. , Schmid J. R. , Sonnenberg K. , Voßnacker P. , Steinhauer S. , Schattenberg C. J. , Müller R. , Kaupp M. , Riedel S.
Published: May 2020

Es wird über eine einfache Eintopfsynthese für Tetraalkylammoniumtetrafluoridochlorat(III), [kat][ClF4] ([kat]=[NEt3Me]+, [NEt4]+), im Gramm‐Maßstab berichtet. In Acetonitril wird ein Chloridsalz bei tiefen Temperaturen mit verdünntem Fluor umgesetzt. Das Zwischenprodukt dieser Reaktion, [ClF2]−, wird zum ersten Mal strukturell charakterisiert. Mögliche Anwendungen des [ClF4]−‐Salzes werden durch folgende Reaktionen eruiert: Diphenyldisulfid, Ph2S2, wird in Pentafluorsulfanylbenzol, PhSF5, überführt, sowie die CN‐Gruppen in Acetonitril und in Tetracyanoborat ([B(CN)4]−) in CF3‐Gruppen. Eine Reaktion mit Kohlenstoffmonoxid, CO, führt zu Fluorphosgen, COF2. Elementares Gold löst sich unter Bildung des Tetrafluoridoaurates, [AuF4]−.
Cobalt Single‐Atom Catalysts with High Stability for Selective Dehydrogenation of Formic Acid
Authors: Li Xiang , Surkus Annette‐Enrica , Rabeah Jabor , Anwar Muhammad , Dastigir Sarim , Junge Henrik , Brückner Angelika , Beller Matthias
Published: May 2020

Metal–organic framework (MOF)‐derived Co‐N‐C catalysts with isolated single cobalt atoms have been synthesized and compared with cobalt nanoparticles for formic acid dehydrogenation. The atomically dispersed Co‐N‐C catalyst achieves superior activity, better acid resistance, and improved long‐term stability compared with nanoparticles synthesized by a similar route. High‐angle annular dark‐field–scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, electron paramagnetic resonance, and X‐ray absorption fine structure characterizations reveal the formation of CoIINx centers as active sites. The optimal low‐cost catalyst is a promising candidate for liquid H2 generation.
Synthesis, crystal structures, fluorescence, electrochemiluminescent properties, and Hirshfeld surface analysis of four Cu/Mn Schiff‐basecomplexes
Authors: Zeng Yumei , Zhang Haiyang , Zhang Yujie , Ji Fanghua , Liang Jinlu , Zhang Shuhua
Published: May 2020

Four new complexes [Cu(L1)2]n (1), [Mn(L1)2]n (2), [Cu(L2)2]n (3), [Mn(L2)2]n (4, HL1 = 2‐(((4H‐1,2,4‐triazol‐4‐yl)imino)methyl)‐4,6‐dichlorophenol; HL2 = 2‐(((4H‐1,2,4‐triazol‐4‐yl)imino)methyl)‐4,6‐dibromophenol) were synthesized by microreaction bottle method. Complexes 1 and 3 and 2 and 4 are isomorphous heterostructures having the same molecular structure. The structures of 1–4 were characterized using single X‐ray diffraction, Fourier‐transform infrared spectroscopy, powder X‐ray diffraction, and thermogravimetric analysis, and their potential applications were analyzed by detecting their fluorescence and electrochemical luminescence (ECL). Hirshfeld surface analysis indicates that X···H (X = Br, Cl) interactions play a crucial role in stabilizing the self‐assembly process of 1–4, which show highly intense ECL in N,N‐dimethylformamide solution and high thermal stability.
Reaction Mechanism and Kinetics study on Addition of CCl4 to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond
Authors: Kang Lixia , Huo Suhong , Meng Lingpeng , Li Xiaoyan
Published: May 2020

Transition metal‐catalyzed atom transfer radical addition (ATRA) reactions are an effective and versatile strategy for constructing carbon–carbon bonds in organic synthesis. Typically, the metal center in this metal‐assisted radical transformation undergoes a reversible redox process. In this work, a quintuply‐bonded dinuclear complex, Mo2(N∧N)2 {N∧N = μ‐κ2‐CH[N(2,6‐iPr2C6H3)]2}, has been investigated as potential catalyst for radical addition of CCl4 to 1‐hexene by performing density functional theory (DFT) calculations. The study shows that the Mo2(N∧N)2‐mediated radical addition reaction is computationally predicted to occur with acceptable activation energies, indicating that the Mo‐Mo quintuple bond can be applied as an effective catalyst for this transformation under mild conditions. The whole reaction involves 3 steps, two of which are metal‐mediated. Firstly, the C‐Cl bond activiation catalyzed by Mo2(N∧N)2 to obtain Mo2(N∧N)2Cl and ·CCl3 radical; Then the ·CCl3 radical interacts with 1‐hexene to get an addition, the addition product reacts with the Mo2(N∧N)2Cl to get the last product and regenerate the catalyst Mo2(N∧N)2. Both the thermodynamic and kinetic study show that the second step is the rate‐determine step. When coordinating solvent pyridine is added to the catalytic reaction, the reaction is suppressed due to their high energies barriers, which is consistent with experimental results.
CDC20 inhibitor Apcin inhibits embryo implantation in vivo and in vitro
Authors: Guo Chuanjia , Kong Fandou , Lv Yunyi , Gao Na , Xiu Xiaoxin , Sun Xiaojing
Published: May 2020

For successful implantation, endometrial receptivity must be established. The high expression of CDC20 in many kinds of malignant tumours has been reported, and it is related to the occurrence and development of tumours. According to these functions, we think that CDC20 may also play important roles in the process of embryo implantation. To prove our hypothesis, we observed the distribution and expression of CDC20 in mouse and human early pregnancy. The effect of E2 and/or P4 on the expression of CDC20 in human endometrial cells was detected by Western blot. To further explore whether CDC20 is an important factor in adhesion and proliferation. The results showed that the expression of CDC20 in the uterus and menstrual cycle of early pregnant mice was spatiotemporal. E2 can promote the expression of CDC20. On the contrary, P4 and E2 + P4 inhibited the expression of CDC20. We also detected the proliferation and adhesion of human endometrial cells. We found that the inhibition of CDC20 with its inhibitor Apcin could reduce the adhesion rate and proliferation ability to RL95‐2 and HEC‐1A cells, respectively. Inhibiting CDC20 by Apcin could interfere the embryo implantation of mouse. It is suggested that CDC20 may play an important role in the process of embryo implantation.

Significance of the study

Embryo implantation is an extremely complex and delicate process, including identification, localisation, adhesion and invasion between embryo and endometrium. Studies have shown the process of embryo implantation is very similar to that of tumour invasion. CDC20 is a cancer‐promoting factor. We found CDC20 is spatially and spatially expressed in mouse and human menstrual cycles and is regulated by oestrogen and progesterone. Apcin can inhibit the adhesion of JAR cells and embryo implantation of mouse. CDC20 may provide a new way to improve the success rate of assisted reproduction.
Biocatalytic Alkylation Cascades: Recent Advances and Future Opportunities for Late‐Stage Functionalization
Authors: McKean Iain J. W. , Hoskisson Paul A. , Burley Glenn A.
Published: May 2020

This Concept article describes the latest developments in the emerging area of late‐stage biocatalytic alkylation. Central to these developments is the ability to efficiently prepare S‐adenosyl methionine (SAM) cofactor analogues and couple this with enzymatic alkyl transfer. Recent developments in the enzymatic synthesis of SAM cofactor analogues are summarized first, followed by their application as alkyl transfer agents catalyzed by methyltransferases (MTases). Second, innovative methods to regenerate SAM cofactors by enzymatic cascades is reported. Finally, future opportunities towards establishing a generalized platform for late‐stage alkylation are described.
Left ventricular pacing induced polymorphic ventricular tachycardia via the adaptive left ventricle pacing algorithm
Authors: Khalil Fouad , Del‐Carpio Munoz Freddy , Deshmukh Abhishek , Killu Ammar M.
Published: May 2020

Providers should be aware of the possibility of cardiac resynchronization therapy‐related proarrhythmia which could be life‐threatening. His‐bundle pacing may serve as an alternative, more physiological, option in the management as it preserves the normal sequence of depolarization from the septum to the lateral wall, and from endocardium to epicardium.
Syntheses of Pt‐Ni Hollow Nanoalloy for Hydrogen Generation from Catalytic Hydrolysis of Ammonia Borane
Authors: Li Zhao , Pei Qijun , Yu Yang , Jing Zijun , Wang Jintao , He Teng
Published: May 2020

Efficient bimetallic nano‐catalysts consisting of both noble metals and non‐noble metals, are highly desired for the development of new hydrogen storage materials. In this work, supported Pt−Ni nanoalloys with hollow structures were successfully synthesized using galvanic replacement method and exhibited excellent catalytic activity with a turnover frequency as high as 302.3 molH2 ⋅ molmetal−1 ⋅ min−1 for the hydrolysis of ammonia borane. The chemical composition and structure of the alloy can be rationally controlled by the synthetic conditions, which further tune the catalytic activities of hydrogen evolution.
Activity‐Directed Synthesis of Inhibitors of the p53/hDM2 Protein–Protein Interaction
Authors: Green Adam I. , Hobor Fruzsina , Tinworth Christopher P. , Warriner Stuart , Wilson Andrew J. , Nelson Adam
Published: May 2020

Protein–protein interactions (PPIs) provide a rich source of potential targets for drug discovery and biomedical science research. However, the identification of structural‐diverse starting points for discovery of PPI inhibitors remains a significant challenge. Activity‐directed synthesis (ADS), a function‐driven discovery approach, was harnessed in the discovery of the p53/hDM2 PPI. Over two rounds of ADS, 346 microscale reactions were performed, with prioritisation on the basis of the activity of the resulting product mixtures. Four distinct and novel series of PPI inhibitors were discovered that, through biophysical characterisation, were shown to have promising ligand efficiencies. It was thus shown that ADS can facilitate ligand discovery for a target that does not have a defined small‐molecule binding site, and can provide distinctive starting points for the discovery of PPI inhibitors.
Triquinoline‐ versus Fullerene‐Based Cycloparaphenylene Ionic Complexes: Comparison of Photoinduced Charge‐Shift Reactions
Authors: Stasyuk Anton J. , Stasyuk Olga A. , Solà Miquel , Voityuk Alexander A.
Published: May 2020

A triquinoline cationic moiety (TQ⋅H+) has recently been designed as a novel molecular unit for supramolecular chemistry. In addition to some useful features, TQ⋅H+ has strong electron‐acceptor properties, which renders the molecular cation a unique element in nanochemistry. TQ⋅H+ is found to form complexes with coronene (COR) and cycloparaphenylene (CPP). In this work, we report a computational study of photoinduced electron transfer in supramolecular complexes TQ⋅H+‐COR, TQ⋅H+⊂[12]CPP and (TQ⋅H+‐COR)⊂[12]CPP. The electron‐transfer rates are estimated by using the semi‐classical approach. The results are compared with the data previously obtained for a structurally similar inclusion complex Li+@C60⊂[10]CPP. In particular, we found a red solvatochromic shift for charge‐shift bands in the TQ⋅H+‐complexes unlike a blueshift showed by Li+@C60⊂[10]CPP. This distinction is explored in terms of electronic and structural features of the systems.
Synthesis of Chiral MOF‐74 Frameworks by Post‐Synthetic Modification by Using an Amino Acid
Authors: Gheorghe Andreea , Strudwick Benjamin , Dawson Daniel M. , Ashbrook Sharon E. , Woutersen Sander , Dubbeldam David , Tanase Stefania
Published: May 2020

The synthesis of chiral metal–organic frameworks (MOFs) is highly relevant for asymmetric heterogenous catalysis, yet very challenging. Chiral MOFs with MOF‐74 topology were synthesised by using post‐synthetic modification with proline. Vibrational circular dichroism studies demonstrate that proline is the source of chirality. The solvents used in the synthesis play a key role in tuning the loading of proline and its interaction with the MOF‐74 framework. In N,N′‐dimethylformamide, proline coordinates monodentate to the Zn2+ ions within the MOF‐74 framework, whereas it is only weakly bound to the framework when using methanol as solvent. Introducing chirality within the MOF‐74 framework also leads to the formation of defects, with both the organic linker and metal ions missing from the framework. The formation of defects combined with the coordination of DMF and proline within the framework leads to a pore blocking effect. This is confirmed by adsorption studies and testing of the chiral MOFs in the asymmetric aldol reaction between acetone and para‐nitrobenzaldehyde.
Di‐ and Tetracyano‐Substituted Pyrene‐Fused Pyrazaacenes: Aggregation in the Solid State
Authors: Ueberricke Lucas , Ciubotaru Ioana , Ghalami Farhad , Mildner Felix , Rominger Frank , Elstner Marcus , Mastalerz Michael
Published: May 2020

Five di‐ and tetracyano‐substituted pyrene‐fused pyrazaacenes were synthesized and studied as potential electron acceptors in the solid state. Single crystals of all compounds were grown and the crystal packing studied by DFT calculations (transfer integrals and reorganization energies) to get insight into possible use for semiconducting charge transport.
Isothermal crystallization of PLA: Nucleation density and growth rates of α and α' phases
Authors: Foglia Fabiana , De Meo Annarita , Iozzino Valentina , Volpe Valentina , Pantani Roberto
Published: May 2020

From a technological point of view, poly(lactic acid) (PLA) is one of the most important polymers produced from renewable sources, due to its versatility, relatively acceptable processability, and low cost. However, a significant limitation exists in its slow crystallization kinetics, which results in amorphous products having low mechanical properties and thermal resistance. For this reason, quantitative knowledge of the phenomenon of crystallization kinetics is fundamental. In this work, the crystallization kinetics in quiescent conditions of a commercial grade of PLA was analyzed in terms of nucleation and growth rates by direct morphological observations at different crystallization temperatures (Tc) and by calorimetric analysis in isothermal and non‐isothermal conditions. The optical analysis showed a spherulitic morphology with radial growth of the lamellae. The analysis of the growth rate evidenced the α/α'‐crystals polymorphism with a transition temperature of ~120°C. Based on experimental observation, the crystallization kinetics of the two crystalline phases were assessed.
On the Formation of the Popcorn Flavorant 2,3‐Butanedione (CH3COCOCH3) in Acetaldehyde‐Containing Interstellar Ices
Authors: Kleimeier N. Fabian , Turner Andrew M. , Fortenberry Ryan C. , Kaiser Ralf I.
Published: May 2020

Acetaldehyde (CH3CHO) is ubiquitous throughout the interstellar medium and has been observed in cold molecular clouds, star forming regions, and in meteorites such as Murchison. As the simplest methyl‐bearing aldehyde, acetaldehyde constitutes a critical precursor to prebiotic molecules such as the sugar deoxyribose and amino acids via the Strecker synthesis. In this study, we reveal the first laboratory detection of 2,3‐butanedione (diacetyl, CH3COCOCH3) – a butter and popcorn flavorant – synthesized within acetaldehyde‐based interstellar analog ices exposed to ionizing radiation at 5 K. Detailed isotopic substitution experiments combined with tunable vacuum ultraviolet (VUV) photoionization of the subliming molecules demonstrate that 2,3‐butanedione is formed predominantly via the barrier‐less radical–radical reaction of two acetyl radicals (CH3ĊO). These processes are of fundamental importance for a detailed understanding of how complex organic molecules (COMs) are synthesized in deep space thus constraining the molecular structures and complexity of molecules forming in extraterrestrial ices containing acetaldehyde through a vigorous galactic cosmic ray driven non‐equilibrium chemistry.
Retracted: Building a richer understanding of diversity through causally consistent evenness measures
Authors: Pierson Kawika
Published: May 2020

Causally consistent evenness measures can only be changed when the populations they refer to change. This novel property is deeply important for making causal inferences, and yet every prominent evenness measure is not causally consistent. This paper proposes a family of causally consistent evenness measures, and while any evenness measure can be made to be causally consistent, the family I introduce has the added benefit of a straightforward interpretation as a percentage evenness. I go on to illustrate the performance of these measures, and demonstrate the importance of causal consistency not only for causal inference but also for correctly reflecting the evenness of ecological communities. I also present several alternative transformations of my preferred measures, which work to address potential critiques in advance, communicate evenness to nontechnical audiences, and connect my work to more familiar ecological indicators.
Ethylene‐Bridged Tetradentate Bis(amidines): Supramolecular Assemblies through Hydrogen Bonding and Photoluminescence upon Deprotonation
Authors: Calderón‐Díaz Alvaro , Arras Janet , Miller Ethan T. , Bhuvanesh Nattamai , McMillen Colin D. , Stollenz Michael
Published: May 2020

Sterically crowded tetradentate bis(amidines) encapsulate their N–H functionalities or unveil them to undergo inter‐ and intramolecular hydrogen bonding both in solid state and solution, depending on a subtle interplay between the amidine backbone substituents. X‐ray crystallography reveals for four distinct ZZ(syn/syn) and EE(syn/syn) bis(amidines) that bulky terminal N‐Mes groups in combination with N2C‐tBu or N2C‐Ph substituents result in steric protection of the N–H moieties, whereas less crowded terminal p‐tBu(C6H4) groups either show encapsulation (N2C‐tBu) or hydrogen bonding (N2C‐Ph), the latter resulting in a bis(amidine) dimer formed by inter‐ and intramolecular hydrogen bonds. Moreover, a supramolecular solvent adduct consisting of one bis(amidine) and four ethanol molecules is presented. DFT calculations show that both the dimerization and formation of the solvent adduct is associated with a significant energy gain (dimerization: ΔE = –27.7 kcal/mol; formation of ethanol adduct: ΔE = –64.3 kcal/mol). The corresponding four Li bis(amidinates) are weakly blue to green‐emissive in THF solution. Overall, a new series of highly flexible bis(amidines) has been examined.
New Metal‐Free Route towards Imidazole‐Substituted Uridine
Authors: Mattelaer Henri‐Philippe , Van Hool Anne‐Sophie , de Jong Flip , Van der Auweraer Mark , Van Meervelt Luc , Dehaen Wim , Herdewijn Piet
Published: May 2020

Nucleosides with a bi(hetero)aryl nucleobase have unique potential applications as antiviral drugs and molecular probes. The need for transition metal catalysis to synthesize these nucleosides from pre‐functionalized building blocks and the use of nucleobase protection groups results in expensive and tedious syntheses. Herein we report that 5‐imidazolyl‐uracil can be obtained by scalable Van Leusen imidazole synthesis and regioselectively introduced on ribose to obtain the desired nucleoside in a 5 step synthesis (total yield 55 %). The 5‐imidazolyl moiety leads to improved fluorescence properties. The only side‐product formed was characterized by 2D‐NMR and X‐ray crystallography and could be suppressed during synthesis in favor of the desired product.
The Suzuki–Miyaura Cross‐Coupling as the Key Step in the Synthesis of 2‐Aminobiphenyls and 2,2'‐Diaminobiphenyls: Application in the Synthesis of Schiff Base Complexes of Zn
Authors: Hylland Knut Tormodssønn , Øien‐Ødegaard Sigurd , Tilset Mats
Published: May 2020

2‐Nitrophenylboronic acids serve as interesting starting materials for the construction of biphenyl‐ and terphenyl‐based amines if subjected to the Suzuki–Miyaura reaction. Unfortunately, these boronic acids suffer from low reactivity in Suzuki reactions, alongside their low stability in the presence of Pd. Herein, a general method for the construction of 2‐nitro‐substituted bi‐ and terphenyls is presented, with special emphasis on the synthesis of 2‐amino‐2'‐nitrobi‐ and terphenyls. Comparisons are made with other boronic acids that have some of the aforementioned issues. Finally, the application of the obtained 2‐amino‐2'‐nitrobi‐ and terphenyls as starting materials for the synthesis of bi‐ and terphenyl based di‐ and triamines is encountered for, with emphasis on the use of these amines as precursors for Schiff base ligands. In addition, the synthesis of some Zn complexes of these ligands is presented.
A Novel Fullerene‐Pyrrole‐Pyrrole‐3‐Carboxylic Acid Nanocomposite Modified Molecularly Imprinted Impedimetric Sensor for Dopamine Determination in Urine
Authors: Ertuğrul Uygun Hilmiye Deniz , Demir M. Nalan
Published: May 2020

In this study, we designed an electrochemical impedance based sensor by using molecularly imprinted fullerene modified pyrrole‐pyrrole‐3‐carboxylic acid copolymers on screen printed carbon electrode to monitor dopamine in real urine samples. All modifications were characterized by electrochemical impedance spectroscopy (EIS) and Scanning Electron Microscopy (SEM). Performance parameters of the developed sensor system were determined by calibration curve performed between 25 ng/mL and 250 ng/mL (R2= 0.9939). LOD and LOQ were 8.77 ng/mL and 26.6 ng/mL, respectively. The developed sensor method was compared with ELISA. The regression analysis between ELISA and the sensor analysis showed good correlation with R2= 0.979
Body Composition of Very Low‐Birth‐Weight Infants Fed Fortified Human Milk: A Pilot Study
Authors: McNelis Kera , Liu Chunyan , Ehrlich Shelley , Fields Christopher , Fields Trayce , Poindexter Brenda
Published: May 2020

Background

Although donor milk is increasingly fed to preterm infants, the resultant quality of growth and body composition is unknown. The aim of this pilot study was to describe the body composition of very low‐birth‐weight infants fed human milk in the neonatal intensive care unit and explore the association between the proportion of donor human milk intake and fat‐free and fat mass deposition.

Methods

Body composition of 30 preterm infants fed maternal and donor human milk was measured by air displacement plethysmography. Regression models were developed to associate each parameter of body composition with the proportion of donor milk intake and other explanatory variables.

Results

The proportion of donor milk intake was negatively associated with body fat percentage (P= .01). Fat‐free massz‐scores ranged from −4.6 to 1.11 (meanz‐score of −0.95, 17th percentile).

Conclusion

Donor human milk intake is negatively associated with body fat percentage in this pilot study of very low‐birth‐weight preterm infants.
Designing for effective controlled release in agricultural products: new insights into the complex nature of the polymer–active agent relationship and implications for use
Authors: Levett Ian , Liao Minjie , Pratt Chris , Redding Matthew , Laycock Bronwyn , Pratt Steven
Published: May 2020

BACKGROUND

Various active chemical agents, such as soil microbial inhibitors, are commonly applied to agricultural landscapes to optimize plant yields or minimize unwanted chemical transformations. Dicyandiamide (DCD) is a common nitrification inhibitor. However, it rapidly decomposes under warm and wet conditions, losing effectiveness in the process. Blending DCD with an encapsulating polymer matrix could help overcome this challenge and slow its release. Here, we encapsulated DCD in a biodegradable matrix of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and investigated the effects of DCD crystal size and loading rates on release rates.

RESULTS

Three DCD crystal size fractions (0–106, 106–250 and 250–420 μm) were blended with PHBV at 200, 400, 600 and 800 gkg−1 loadings through extrusion processing and release kinetics were studied in water over 8 weeks. For loadings ≥ 600 g kg−1, more than 95% release was reached within the first 7 days. By contrast, at 200 g kg−1 loading only 10%, 36% and 57% of the DCD was mobilized after 8 weeks in water for 0 to 106 μm, 106 to 250 μm and 250 to 420 μm crystal size fractions, respectively.

CONCLUSION

The lower percolation threshold for this combination of materials lies between 200 and 400 g kg−1 DCD loading. The grind size fraction of DCD significantly affects the quantity of burst release from the surface of the pellet, particularly below the lower percolation threshold. The results presented here are likely translatable to the encapsulation and release of other crystalline materials from hydrophobic polymer matrices used in controlled release formulations, such as fertilizers, herbicides and pesticides. © 2020 Society of Chemical Industry
Effects of infrared freeze drying on volatile profile, FTIR molecular structure profile and nutritional properties of edible rose flower (Rosa rugosa flower)
Authors: Qiu Liqing , Zhang Min , Bhandari Bhesh , Wang Bin
Published: May 2020

BACKGROUND

Infrared freeze drying (IRFD) utilizes infrared radiation as a novel heating source in freeze drying (FD), leading to high‐quality dehydrated products and less drying time. The present study aimed to investigate the effects of IRFD on the drying characteristics (drying time and energy consumption), volatiles, physical structure and nutritional properties of Rosa rugosa flower. In addition, freeze drying (FD) and hot air drying (HAD) were also evaluated in a comparison with the IFRD drying method with respect to product quality parameters.

RESULTS

Fifty‐six volatile compounds were identified in fresh samples, whereas 53, 51 and 46 volatile compounds were identified in FD, IRFD and HAD samples, respectively. FD and IRFD were relatively more effective than HAD for better retention of volatile compounds of Rosa rugose flower. E‐nose analysis also exhibited similar flavor properties in FD and IRFD samples. The molecular structure properties of FD and IRFD samples measured by FTIR spectroscopy were also similar. As for nutritional properties, HAD dramatically (P < 0.05) reduced the nutritional values of R. rugosa flower after drying. The content of vitamin C (from 14.83 to 12.15 mg 100 g–1), flavonoids (from 478.00 to 333.33 mg 100 g–1) and anthocyanins (from 220.70 to 196.90 mg 100 g–1) in R. rugosa flower is well retained by IRFD and no significant difference (P < 0.05) was observed between FD and IRFD samples.

CONCLUSION

IRFD was found to be effective in retaining the aroma, structure and nutrition of R. rugosa flower, as well as demonstrating a lower energy consumption and shorter drying time. © 2020 Society of Chemical Industry