bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Influencing the Ripening and Quality of Fleshy Fruits
Authors: Barry Cornelius S. 
Published: April 2017

AbstractFleshy fruits have a dual function in the reproductive strategies of plants. Initially, fleshy fruits protect the developing seeds from predation and then, once the seeds are mature, they facilitate dispersal of the enclosed seeds. Plants have evolved numerous chemical and physical barriers that discourage seed predation from fleshy fruits. Similarly, the ripening of fleshy fruits occurs through a range of coordinated biochemical processes that convert an unpalatable unripe fruit into a fruit that is nutritious and desirable to seed‐dispersing fauna. The biochemical changes that occur at the onset of ripening are species specific but several general processes occur that are common to many fruits, suggesting that the mechanisms that control ripening may be evolutionarily conserved. For example, fruit ripening is often accompanied by the accumulation of brightly coloured pigments, the synthesis of aroma volatiles and the conversion of complex carbohydrates into sugars. These changes facilitate seed dispersal strategies. The genetic and biochemical pathways that lead to fruit ripening are not fully understood. However, significant progress has been made in identifying some of the components of these pathways. This review highlights recent research that has contributed to the understanding of the ripening process at the molecular level and outlines the development of genomics‐based resources for fleshy fruit‐bearing species.
Parthenocarpy in Crop Plants
Authors: Pandolfini Tiziana , Molesini Barbara , Spena Angelo 
Published: April 2017

AbstractFruit set and growth in the absence of fertilization (parthenocarpy) is a useful trait in plants grown for the value of their fruit. Auxins and gibberellins are widely used to spray flowers to chemically confer parthenocarpy. In recent years, genetic modifications of either auxin or gibberellin biology have been used to confer parthenocarpy to tomato and other crops. Present knowledge indicates that parthenocarpy can be achieved by genetic modification of either auxin synthesis (iaaM), auxin sensitivity (rolB), auxin content (Aucsia) or auxin signal transduction (IAA9 or ARF8). Genetic modification of gibberellin signal transduction (DELLA) has also been shown to confer parthenocarpy. Available data, obtained under both open field and protected cultivation, show that genetic parthenocarpy can be used to improve fruit production and/or fruit quality. The mechanisms, genetically modified to confer parthenocarpy, are active also in other plant organs. Observations consistent with the Euanthial theory that envisages the fruit as a modified leaf predict that the mechanisms underlying fruit initiation have been recruited from molecular machineries present and controlling other plant developmental processes. The flower/fruit represents the last evolutionary innovation of the green plant lineage, and yet genes (i.e. Aucsia) controlling fruit initiation are most likely older than 1 billion years being present in Prasinophytes (i.e. probable ancestors of Charophytes, which themselves are considered ancestors of all land plants).
Molecular Modes of Action of Defensive Secondary Metabolites
Authors: Wink Michael , Schimmer Oskar 
Published: April 2017

AbstractSecondary metabolites (SM) have been shaped by evolution for more than 500 million years. As a result, many of them have distinctive biochemical and pharmacological properties. The molecular modes of action of the main groups of SM are reviewed in this chapter. Details are given on interactions of SM with proteins that can induce conformational changes and thus a modification of their bioactivity. The fluidity and permeability of biomembranes constitute another important target, which is influenced by many lipophilic and amphiphilic SM. A number of SM can either alkylate or intercalate DNA, which can cause mutations and in consequence cancer or malformations. Many SM are cytotoxic because they interfere with biomembranes, proteins of the cytoskeleton or DNA; they often induce programmed cell death (apoptosis). A large number of SM, especially alkaloids modulate neuronal signal transduction by interfering with ion channels, ion pumps, neuroreceptors, choline esterase, monoamine oxidase and other enzymes related to signal transduction pathways. A typical feature of SM is their ability to modulate more than one molecular target; thus, additive and even synergistic activities can be expected.
Chemical Defence in Marine Ecosystems (FromAPRVolume 39)
Authors: Putz Annika , Proksch Peter 
Published: April 2017

AbstractNature has provided a broad arsenal of structurally diverse and pharmacologically active compounds that serve as highly effective drugs or lead structures for the development of novel drugs to combat a multitude of diseases. Traditionally, terrestrial organisms represent the richest source of natural drugs. Considering the fact that over 70% of the surface of the earth is covered by oceans that harbour a rich biodiversity, aspiration in marine bioprospecting as a viable counterpart for the discovery of bioactive compounds from the terrestrial environment seems justified. Interestingly, the majority of marine natural products involved in clinical or preclinical trials is produced by invertebrates, which is in contrast to compounds derived from the terrestrial environment where plants by far exceed animals with respect to the production of bioactive metabolites. The fact that bioactive metabolites are predominantly found in sessile or slow‐moving marine organisms that lack physical defence structures thus appears to reflect the ecological importance of these compounds with respect to inter‐ as well as intraspecific interactions, for example predation, competition for space and fouling. Numerous natural products from marine invertebrates show striking structural similarities to known metabolites of microbial origin. This fact suggests that microorganisms such as bacteria and microalgae that often live associated with marine invertebrates are at least involved in the biosynthesis or are in fact the true sources of these respective metabolites in many cases.
Production of Natural Products by Plant Cell and Organ Cultures
Authors: Alfermann August‐Wilhelm 
Published: April 2017

Abstract
Natural products have been used as medicines, food additives or in technical applications by humans since thousands of years. Due to various reasons, a sufficient supply of the plant raw material has become increasingly difficult in recent years. Since more than 30 years, laboratories worldwide are trying to produce natural products for commercial application with plant cell and organ cultures. The commercial success of this research is still very limited, due to too low product yields resulting into production costs, which are not acceptable. Among organ cultures, root and hairy root cultures are the most promising for the production of secondary metabolites in good yields. This chapter describes the methods used to overcome these intrinsic problems in product yields and the hopes which are set on the new developments to transfer the appropriate plant genes into microorganisms, which may become more applicable for large scale production of plant natural products than plant cells themselves. First results in this field, e.g. the synthesis of benzylisoquinoline alkaloids in recombinant yeast cells, are already very promising.
Introduction: Biochemistry, Physiology and Ecological Functions of Secondary Metabolites
Authors: Wink Michael 
Published: April 2017

AbstractSecondary metabolites (SM) occur in plants in a high structural diversity. The different classes of SM and their biosynthetic pathways are summarized in this introduction. A typical feature of SM is their storage in relatively high concentrations, sometimes in organs which do not produce them. A long‐distance transport via the phloem or xylem is then required. Whereas hydrophilic substances are stored in the vacuole, lipophilic metabolites can be found in latex, resin ducts, oil cells or cuticle. SM are not necessarily end products and some of them, especially if they contain nitrogen, are metabolically recycled. Biosynthesis, transport and storage are energy‐dependent processes which include the costs for the replication and transcription of the corresponding genes and the translation of proteins. The intricate biochemical and physiological features are strongly correlated with the function of SM: SM are not useless waste products (as assumed earlier), but important tools against herbivores and microbes. Some of them also function as signal molecules to attract pollinating arthropods or seed‐dispersing animals and as signal compounds in other plant – plant, plant – animal and plant – microbe relationships.
Biosynthesis of Phenylpropanoids and Related Compounds (FromAPRVolume 40)
Authors: Petersen Maike , Hans Joachim , Matern Ulrich 
Published: April 2017

AbstractPhenolic compounds are ubiquitous in the plant kingdom. A main pathway for the formation of these compounds starts with the aromatic amino acidsl‐phenylalanine and – to a lesser extent –l‐tyrosine. In the general phenylpropanoid pathway, these are transformed to coenzyme A‐activated 4‐coumaric acid by phenylalanine ammonia‐lyase, cinnamic acid 4‐hydroxylase and 4‐coumarate CoA‐ligase. 4‐Coumaroyl‐CoA gives rise to a large number of different natural products, e.g. flavonoids, lignans, coumarins, tannins, hydroxycinnamic acid esters and amides as well as lignin monomers. This review gives an insight into recent findings concerning the general phenylpropanoid pathway as well as the biosyntheses of hydroxycinnamoyl conjugates, phenolic aroma and fragrance compounds, lignans, coumarins and gallo‐/ellagitannins.
Gibberellins in Fungi, Bacteria and Lower Plants: Biosynthesis, Function and Evolution
Authors: Tudzynski Bettina , Studt Lena , Rojas María Cecilia 
Published: April 2017

AbstractThe rice pathogenFusarium fujikuroi, as well as two distantly related fungi,Sphaceloma manihoticolaandPhaeosphaeriaesp., contains clusters of gibberellin (GA) biosynthesis genes and produces GAs. Fungal GAs are structurally identical to those synthesised by higher plants, although the respective biosynthetic pathways, genes and enzymes differ. Besides fungi, some bacteria synthesise GAs. An operon of GA biosynthesis genes was found in the symbiotic rhizobacteriumBradyrhizobium japonicumand in otherRhizobiumspecies. This operon encodes the enzymes of GA9biosynthesis and includes a reductase or alcohol dehydrogenase gene not present in fungal clusters. Differences between genes and enzymes indicate convergent evolution of the GA biosynthesis pathway in higher plants, fungi and bacteria. In contrast to higher plants, GAs are not produced by all lower plants. Mosses or liverworts synthesiseent‐kaurenoids, but not GAs, while lycophytes and ferns synthesise GAs or GA‐related products that participate in the regulation of reproductive development.
“Never enough hours in the day”: Employed mothers’ perceptions of time pressure
Authors: Rose Judy 
Published: April 2017

AbstractFinding sufficient time to meet work and family commitments poses immense challenges for employed mothers in 21st century contemporary life. Understanding how employed women with children manage their finite time resources requires deeper investigation of how time pressures accrue across work and home contexts. This study draws on data from in‐depth interviews with 18 working mothers from diverse occupations (professional, sales, service, clerical, technical and trades) and across a range of employment hours (full and part‐time). The findings from this study show that employed mothers endure high levels of time pressure related to time poverty (insufficient time for necessary or discretionary activities), time intensity (multitasking and merging work and home boundaries) and time density (familial emotion and organisation work). When women use strategies to increase time efficiency, it does not necessarily reduce their perceptions of time pressure. Juggling multiple tasks simultaneously distorts women's temporal experiences and diminishes the quality of time. Workplaces and policymakers need to find better ways to encourage employed fathers to share the responsibility for home‐ and family‐related care and organisational work. Such measures may reduce the time stress and time inequity women endure, particularly in the time management control centre of the home.
Non‐Thermal Plasma Activation of Gold‐Based Catalysts for Low‐Temperature Water–Gas Shift Catalysis
Authors: Stere Cristina E. , Anderson James A. , Chansai Sarayute , Delgado Juan Jose , Goguet Alexandre , Graham Willam G. , Hardacre C. , Taylor S. F. Rebecca , Tu Xin , Wang Ziyun , Yang Hui 
Published: April 2017

AbstractNon‐thermal plasma activation has been used to enable low‐temperature water‐gas shift over a Au/CeZrO4 catalyst. The activity obtained was comparable with that attained by heating the catalyst to 180 °C providing an opportunity for the hydrogen production to be obtained under conditions where the thermodynamic limitations are minimal. Using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), structural changes associated with the gold nanoparticles in the catalyst have been observed which are not found under thermal activation indicating a weakening of the Au−CO bond and a change in the mechanism of deactivation.
Magneto‐Adaptive Surfactants Showing Anti‐Curie Behavior and Tunable Surface Tension as Porogens for Mesoporous Particles with 12‐Fold Symmetry
Authors: Hermann Stefanie , Wessig Martin , Kollofrath Dennis , Gerigk Melanie , Hagedorn Kay , Odendal James A. , Hagner Matthias , Drechsler Markus , Erler Philipp , Fonin Mikhail , Maret Georg , Polarz Sebastian 
Published: April 2017

AbstractGaining external control over self‐organization is of vital importance for future smart materials. Surfactants are extremely valuable for the synthesis of diverse nanomaterials. Their self‐assembly is dictated by microphase separation, the hydrophobic effect, and head‐group repulsion. It is desirable to supplement surfactants with an added mode of long‐range and directional interaction. Magnetic forces are ideal, as they are not shielded in water. We report on surfactants with heads containing tightly bound transition‐metal centers. The magnetic moment of the head was varied systematically while keeping shape and charge constant. Changes in the magnetic moment of the head led to notable differences in surface tension, aggregate size, and contact angle, which could also be altered by an external magnetic field. The most astonishing result was that the use of magnetic surfactants as structure‐directing agents enabled the formation of porous solids with 12‐fold rotational symmetry.
Anisotropic Polymer Nanoparticles with Tunable Emission Wavelengths by Intersegmental Chain Packing
Authors: Ruiz Perez Julian D. , Mecking Stefan 
Published: April 2017

AbstractThe shape of nanoparticles is decisive for their self‐assembly properties, as well as for the behavior of individual particles in many instances. The introduction and control of anisotropy is well‐known for inorganic nanocrystals but a largely unresolved problem for polymer nanoparticles, especially for conjugated polymers. Here, we report a reproducible preparation method using heterophase polymerization for a range of stable dispersions of ellipsoidal conjugated polymer nanoparticles with sizes in the range of 50 to 180 nm and narrow size and shape distributions. The nanoparticles show a bright fluorescence with tunable emission wavelengths and quantum yields as high as ϕ=78 %. Structural investigations reveal the nanoparticles to be composed of a highly ordered β‐ and α′‐phase within a nematic matrix. Preliminary studies on the origin of particle anisotropy suggest a concerted mechanism in which anisotropic shape evolves from intersegmental packing that occurs along with progressing chain formation by polymerization.
From Two‐ to Three‐Dimensional Structures of a Supertetrahedral Boran Using Density Functional Calculations
Authors: Getmanskii Iliya V. , Minyaev Ruslan M. , Steglenko Dmitrii V. , Koval Vitaliy V. , Zaitsev Stanislav A. , Minkin Vladimir I. 
Published: April 2017

AbstractWith help of the DFT calculations and imposing of periodic boundary conditions the geometrical and electronic structures were investigated of two‐ and three‐dimensional boron systems designed on the basis of graphane and diamond lattices in which carbons were replaced with boron tetrahedrons. The consequent studies of two‐ and three‐layer systems resulted in the construction of a three‐dimensional supertetrahedral borane crystal structure. The two‐dimensional supertetrahedral borane structures with less than seven layers are dynamically unstable. At the same time the three‐dimensional superborane systems were found to be dynamically stable. Lack of the forbidden electronic zone for the studied boron systems testifies that these structures can behave as good conductors. The low density of the supertetrahedral borane crystal structures (0.9 g cm−3) is close to that of water, which offers the perspective for their application as aerospace and cosmic materials.
Shape‐Shifting Patchy Particles
Authors: Zheng Xiaolong , Liu Mingzhu , He Mingxin , Pine David J. , Weck Marcus 
Published: April 2017

AbstractA facile method to synthesize shape‐shifting patchy particles on the colloidal scale is described. The design is based on the solvent‐induced shifting of the patch shape between concave and convex features. The initial concave patchy particles were synthesized in a water suspension by a swelling‐induced buckling process. Upon exposure to different solvents, the patches were tuned reversibly to be either concave or convex. These particles can be assembled into chained, branched, zigzag, and cyclic colloidal superstructures in a highly site‐specific manner by surface–liquid capillary bridging. The biphasic nature of the particles also enables site‐selective surface functionalization.
A Fully Phosphane‐Substituted Disilene
Authors: Izod Keith , Evans Peter , Waddell Paul G. 
Published: April 2017

AbstractThere is growing interest in compounds containing functionalized E=E multiple bonds (E=Si, Ge, Sn, Pb) because of their potential to exhibit novel physical and chemical properties. However, compounds containing multiple functionalizations are rare, with scarcity increasing with increasing degree of substitution. The first ditetrelene R2E=ER2 in which the E=E bond is substituted by four heteroatoms (other than Si) is described. The tetraphosphadisilene {(Mes)2P}2Si=Si{P(Mes)2}2 (7) is readily isolated from the reaction between SiBr4 and [(Mes)2P]Li, the latter of which acts as a sacrificial reducing agent. The structure of 7 is presented, while the bonding in, and stability of 7 were probed using DFT calculations.
A Plastic–Crystal Electrolyte Interphase for All‐Solid‐State Sodium Batteries
Authors: Gao Hongcai , Xue Leigang , Xin Sen , Park Kyusung , Goodenough John B. 
Published: April 2017

AbstractThe development of all‐solid‐state rechargeable batteries is plagued by a large interfacial resistance between a solid cathode and a solid electrolyte that increases with each charge–discharge cycle. The introduction of a plastic–crystal electrolyte interphase between a solid electrolyte and solid cathode particles reduces the interfacial resistance, increases the cycle life, and allows a high rate performance. Comparison of solid‐state sodium cells with 1) solid electrolyte Na3Zr2(Si2PO4) particles versus 2) plastic–crystal electrolyte in the cathode composites shows that the former suffers from a huge irreversible capacity loss on cycling whereas the latter exhibits a dramatically improved electrochemical performance with retention of capacity for over 100 cycles and cycling at 5 C rate. The application of a plastic–crystal electrolyte interphase between a solid electrolyte and a solid cathode may be extended to other all‐solid‐state battery cells.
Switch in Catalyst State: Single Bifunctional Bi‐state Catalyst for Two Different Reactions
Authors: Semwal Shrivats , Choudhury Joyanta 
Published: April 2017

AbstractDisclosed here is a molecular switch which responds to acid‐base stimuli and serves as a bi‐state catalyst for two different reactions. The two states of the switch serve as a highly active and poorly active catalyst for two catalytic reactions (namely a hydrogenation and a dehydrogenative coupling) but in a complementary manner. The system was used in an assisted tandem catalysis set‐up involving dehydrogenative coupling of an amine and then hydrogenation of the resulting imine product by switching between the respective states of the catalyst.
Photo‐ and Electronically Switchable Spin‐Crossover Iron(II) Metal–Organic Frameworks Based on a Tetrathiafulvalene Ligand
Authors: Wang Hai‐Ying , Ge Jing‐Yuan , Hua Carol , Jiao Cheng‐Qi , Wu Yue , Leong Chanel F. , D'Alessandro Deanna M. , Liu Tao , Zuo Jing‐Lin 
Published: April 2017

AbstractA major challenge is the development of multifunctional metal–organic frameworks (MOFs), wherein magnetic and electronic functionality can be controlled simultaneously. Herein, we rationally construct two 3D MOFs by introducing the redox active ligand tetra(4‐pyridyl)tetrathiafulvalene (TTF(py)4) and spin‐crossover FeII centers. The materials exhibit redox activity, in addition to thermally and photo‐induced spin crossover (SCO). A crystal‐to‐crystal transformation induced by I2 doping has also been observed and the resulting intercalated structure determined. The conductivity could be significantly enhanced (up to 3 orders of magnitude) by modulating the electronic state of the framework via oxidative doping; SCO behavior was also modified and the photo‐magnetic behavior was switched off. This work provides a new strategy to tune the spin state and conductivity of framework materials through guest‐induced redox‐state switching.
Complementary Lock‐and‐Key Ligand Binding of a Triplet Transmitter to a Nanocrystal Photosensitizer
Authors: Li Xin , Fast Alexander , Huang Zhiyuan , Fishman Dmitry A. , Tang Ming Lee 
Published: April 2017

AbstractOwing to the difficulty in comprehensively characterizing nanocrystal (NC) surfaces, clear guidance for ligand design is lacking. In this work, a series of bidentate bis(pyridine) anthracene isomers (2,3‐PyAn, 3,3‐PyAn, 2,2‐PyAn) that differ in their binding geometries were designed to find the best complementary fit to the NC surface. The efficiency of triplet energy transfer (TET) from the CdSe NC donor to a diphenylanthracene (DPA) acceptor mediated by these isomers was used as a proxy for the efficacy of orbital overlap and therefore ligand binding. 2,3‐PyAn, with an intramolecular N–N distance of 8.2 Å, provided the best match to the surface of CdSe NCs. When serving as a transmitter for photon upconversion, 2,3‐PyAn yielded the highest upconversion quantum yield (QY) of 12.1±1.3 %, followed by 3,3‐PyAn and 2,2‐PyAn. The TET quantum efficiencies determined by ultrafast transient absorption measurements showed the same trend.
Synthesis and Bowl‐in‐Bowl Assembly of a Geodesic Phenylene Bowl
Authors: Ikemoto Koki , Kobayashi Ryo , Sato Sota , Isobe Hiroyuki 
Published: April 2017

AbstractA phenylene multiring with a corannulenoidal skeleton was synthesized. Geodesic constraints over 20 phenylene panels resulted in its nanometer‐sized, bowl‐shaped molecular structure, which was unequivocally revealed by crystallographic analysis. The crystal structure also showed the presence of a bowl‐in‐bowl dimeric assembly, which was driven by entropic factors in solution.