bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluctuations in ribosomal RNA gene content and nucleolar activity in the cambial region of Abies balsamea (Pinaceae) shoots during reactivation
Authors: Lloyd Andrew D. , Mellerowicz Ewa J. , Chow Cynthia H. , Riding Richard T. , Little C. H. Anthony
Published: January 2018

Tissue was collected from the vascular cambial region of 1‐year‐old balsam fir shoots over an 11‐week period during which cambial reactivation occurred. The amount of rDNA (ribosomal RNA genes) relative to total genomic DNA was determined by quantitative slot blots for three trees, one of which showed a 3‐week delay in reactivation. In addition, nucleolar activity was estimated by measuring nucleolar volume, number, and staining intensity. Relative rRNA gene content increased transiently prior to the onset of cambial cell periclinal division. Nucleolar volume also increased transiently, but 1–2 weeks prior to the maximal relative rDNA value. The increases in relative rDNA and nucleolar activity were delayed in the tree in which reactivation was late. We interpret these changes as reflecting the amplification and loss of genes encoding rRNA to facilitate cambial cell reactivation.
The evolution of embryogeny in seed plants and the developmental origin and early history of endosperm
Authors: Friedman William E.
Published: January 2018

For almost a century, the formation of endosperm from a second and distinctive fertilization event has been viewed as a unique feature of flowering plants. However, until recently, the evolutionary origin of this unique embryo‐nourishing entity remained a mystery. Based upon comparative developmental analysis of reproduction among basal angiosperms and their closest extant relatives, the Gnetales (Ephedra, Gnetum, and Welwitschia), it is possible to construct an explicit hypothesis of the events that led to the evolutionary establishment of double fertilization and endosperm. The formulation of this historical record is derived entirely from and dependent upon the determination of reproductive features that are likely to have characterized the common ancestors of angiosperms and Gnetales. Current evidence is most congruent with the concept that a process of double fertilization first evolved in a common ancestor of the Gnetales and angiosperms. Initially, however, the second fertilization product was diploid and yielded a supernumerary embryo. Subsequent to the divergence of the angiosperm lineage from its closest relatives (which include the Gnetales), modification of the development of the supernumerary embryo (derived from the second fertilization event) led to the establishment of an embryo‐nourishing endosperm. Comparative analysis of patterns of embryogeny within Gnetales and angiosperms establishes that embryo development in the ancestors of flowering plants (with a rudimentary process of double fertilization) was ab initio cellular, and not free nuclear, as had previously been assumed. Thus, it is likely that the earliest flowering plants displayed an ab initio cellular pattern of endosperm development, whose expression was inherited from that of the supernumerary embryo of the ancestors of flowering plants.
Karyotypic study of some species ofSerjaniaandUrvillea (Sapindaceae; Tribe Paullinieae)
Authors: Nogueira Claudia Zampieri , Ruas Paulo M. , Ruas Claudete F. , Ferrucci Maria S.
Published: January 2018

Karyotypes of six species (in ten populations) of the genus Serjania and one species of the genus Urvillea were studied using root tip mitotic metaphases. All species of Serjania were diploids with 2n = 24 chromosomes and the species of Urvillea was octoploid with 2n = 86 chromosomes. Analysis of the karyotypes of Serjania showed that the species are differentiated by chromosomic structural changes. Chromosome lengths showed great differences among the species that may be explained by chromosomal deletion or addition. The basic chromosomic number is x = 12 for Serjania and x = 11 for Urvillea. In Urvillea the evolutionary trend may be toward polyploidy followed by reductional aneuploidy. The Giemsa (C‐band) staining technique was applied in Serjania; however, no clear blocks of heterochromatin were observed. This result agrees with the presence of semireticulate nuclei. The Nucleolar Organizing Region (NOR‐banding) technique was applied in S. communis and S. laruotteana, which showed one and two pairs stained, respectively. Variation in the number of nucleoli was observed among the different populations of Serjania. This variation could be explained by the presence of small nucleolar organizer regions that occur scattered along the genome and are not detected by the silver staining methodology.
POPULATION DYNAMIC CONSEQUENCES AND EVOLUTION OF SEED TRAITS OF HETEROSPERMA PINNATUM (ASTERACEAE)
Authors: Venable D. Lawrence , Dyreson Eric , Morales Eduardo
Published: January 2018

We summarize research on variation in achene morphology of Heterosperma pinnatum. Each flowering head has a broad range of achene morphologies. There is no between‐year seed bank. There are no ecologically relevant differences in achene size, seedling size, or seedling growth rates of the different morphs. Achenes located centrally in the heads lose dormancy earlier during the period between autumn achene production and the onset (May‐July) of the rainy season. This results in relatively more early emergence of central achenes. Awned central achenes also have greater adhesive dispersibility. Emergence, survival, and fecundity were measured for achenes sown into natural populations in central Mexico. When harsh conditions result in few seeds surviving to reproduce, the advantage tends to go to the more “conservative” peripheral achenes. Greenhouse experiments show a strong genetic component to the determination of achene proportions within and among populations and a variety of genetic correlations. Populations with a high proportion of awned achenes tend to be found in vegetation types where they are likely to be ephemeral. A high proportion of central achenes tend to be found in sites with little pre‐rainy season precipitation. These patterns are interpreted in terms of selection for dispersal and the within‐year timing of germination.
DOES DAPI DETECT CYTOPLASMIC DNA?
Authors: Johansen Bo , Seberg Ole , Petersen Gitte , Arctander Peter
Published: January 2018

Ultrastructural observations have revealed that plastids are present in orchid pollen tubes, but the DNA‐binding fluorochrome 4',6‐diamidino‐2‐phenylindole (DAPI) does not localize any DNA in the pollen tube plastids at optimum binding and flourescence conditions. However, the plastids do contain DNA since the gene coding for the large subunit of rubisco (ribulose‐1,5‐bisphosphate carboxylase/oxygenase, rbcL) has been amplified by the polymerase chain reaction from orchid pollen tubes. It is therefore concluded that DAPI is an unreliable fluorochrome for detecting plastid DNA.
Reiterative production and deformation of cell walls in expanding thallus nets of the lichen ramalina menziesii (Lecanorales, Ascomycetes)
Authors: Sanders William B. , Ascaso Carmen
Published: January 2018

The thallus of the lichen Ramalina menziesii Tayl. is composed of net‐like units that develop by diffuse expansion of perforated tissue produced at the net apex. Study of net tissue with transmission electron microscopy reveals that the cortical cells are surrounded by a succession of cell walls alternating with layers of an electron‐transparent matrix substance. In the course of thallus growth the cortical cell walls are continually deformed and new ones constructed. The deposition of new walls and matrix layers displaces the older walls centrifugally from the cell. Electron‐dense boundaries develop at the interfaces among cells where the remains of the oldest walls are compressed against those of neighboring cells. As new branch cells are inserted through the concentric accumulations, the dense boundaries appear to enclose fascicles of cells, visible in cross section with light microscopy. Cortical organization in Ramalina menziesii is contrasted with that reported in other lichens, and a functional relationship to diffuse growth of the thallus is suggested.
A chloroplast DNA Phylogenetic study of the eastern Asia‐eastern North America disjunct sectionRytidospermumofMagnolia(Magnoliaceae)
Authors: Qiu Yin‐Long , Chase Mark W. , Parks Clifford R.
Published: January 2018

Chloroplast DNA restriction site variation of ten endonucleases was examined among all ten species or varieties of the eastern Asia–eastern North America disjunct sectionRytidospermumofMagnolia.Representatives from seven of the other ten sections ofMagnoliaand four related genera (Liriodendron, Manglietia, Michelia,andTalauma) were also included in the survey. A cladistic analysis of 200 variable sites using Wagner parsimony yielded 11 equally most parsimonious trees with a consistency index of 0.793 and a retention index of 0.870. The sectionRytidospermumis polyphyletic in these trees.Magnolia tripetalafrom the southeastern U.S. is the only American species that has a sister relationship to the Asian taxa,M. hypoleuca, M. officinalisvar.officinalis, M. officinalisvar.biloba,andM. rostrata.Other American taxa in the section fall into two lineages, withM. macrophyllavar.macrophylla, M. macrophyllavar.ashei,andM. macrophyllavar.dealbatain one, andM. fraserivar.fraseriandM. fraserivar.pyramidatain the other. They are not related to the Asian species as previously believed. The relationships revealed here are in agreement with morphological, allozymic, and cross compatibility data. These results demonstrate that a robust phylogenetic hypothesis is an important prerequisite for understanding biogeographic patterns.
Population genetics ofCordia alliodora(Boraginaceae), a neotropical tree. 2. Mating system
Authors: Boshier David H. , Chase Michael R. , Bawa Kamaljit S.
Published: January 2018

A multilocus mixed mating model was used to evaluate the mating system of a natural population ofCordia alliodora(Boraginaceae), a neotropical tree. The population was highly outcrossed (tm= 0.966 ± 0.027), in agreement with results from controlled crosses. Departures from the mixed mating model were evident, suggesting some nonrandom, correlated mating. Pollen pool heterogeneity and variation in estimates of individual outcrossing rates indicated that the population may be genetically substructured. Individual outcrossing rates obtained for the samples taken from within different parts of the same tree indicated reduced levels of outcrossing due to limited sampling of the pollen pool. The incompatibility mechanism inC. alliodora, combined with variation in flowering and stand density, appears to lead to both temporal and spatial substructuring of the population.
Embryophytes have equivalent sexual phenotypes and breeding systems: why not a common terminology to describe them?
Authors: Cruden Robert W. , Lloyd Robert M.
Published: January 2018

From our review of the literature it is clear that bryophytes, pteridophytes, and flowering plants, indeed most embryophytes, have equivalent sexual phenotypes and mating/breeding systems. We demonstrate that these phenotypes can be described with a common terminology, even though the reproductive structures of the groups are quite different. We consider morphological, functional, and temporal phenotypes and recommend the use of common terms such as unisexual, bisexual, male, female, and hermaphroditic in lieu of taxon‐specific terms such as monoclinous, staminate, and perichaetial. We use self‐ and cross‐fertilization and self‐ and cross‐pollination to describe those processes. Likewise, inbreeding, mixed‐breeding, and outbreeding can be used to describe breeding systems. Automixis, autogamy, facultative xenogamy, and xenogamy provide a more precise circumscription of mating/breeding systems. The use of well‐known terms and a common terminology should improve communication among systematists, reproductive biologists, and/or evolutionary biologists, whether they work with bryophytes, pteridophytes, gymnosperms, or angiosperms, and with the broader biological community.
Identification of an allelopathic compound from Ailanthus altissima (Simaroubaceae) and characterization of its herbicidal activity
Authors: Heisey Rod M.
Published: January 2018

Aqueous extracts of Ailanthus altissima bark and foliage were previously shown to be toxic to other plants. Using bioassay‐directed fractionation, I isolated the phytotoxic compound from A. altissima root bark and identified it to be ailanthone, a quassinoid compound having molecular mass of 376. Ailanthone was highly phytotoxic, with concentrations of 0.7 ml/L causing 50% inhibition of radicle elongation in a standardized bioassay with garden cress (Lepidium sativum) seeds. Ailanthone exhibited potent pre‐ and postemergence herbicidal activity in greenhouse trials. Postcmergence activity was especially striking; even the lowest application rate (0.5 kg/ha) caused complete mortality of five of the seven plant species tested within 5 d of treatment. In contrast, the highest application rate (8 kg/ha) did not cause any detectable injury to A. altissima seedlings, indicating the presence of a protective mechanism in the producer species to prevent autotoxicity. Ailanthone was rapidly detoxified in field soil as a result of microbial activity. Applications of ailanthone equivalent to 0.5 and 4.0 kg/ha completely lost their phytotoxicity within ≤5 d when incubated in the presence of nonsterile soil. When incubated with sterile soil under identical conditions, however, ailanthone remained highly phytotoxic throughout the 21‐d duration of the investigation. The high level of postemergence herbicidal activity in conjunction with its rapid biodegradation in soil suggest ailanthone may have potential for development as a natural‐product herbicide.
Asymptotic height as a predictor of growth and allometric characteristics in malaysian rain forest trees
Authors: Thomas Sean C.
Published: January 2018

The growth and physiological characteristics of canopy trees are expected to differ systematically from those of understory trees on the basis of size‐dependent aspects of biomechanics, resource availability, and life history. Although such differences have previously been noted, there has been relatively little effort to quantify these in terms of interspecific allometric relationships. Asymptotic maximal height (Hmax) is advocated as a measure of the size of dicotyledonous woody plants for this purpose. Height diameter (H–D) relationships in 38 species within six genera of Malaysian rain forest trees are well described by an asymptotic model, and thus provide a basis for estimatingHmaxusing static observational data. Three important aspects of tree growth strategies are shown to be predictable on the basis of these values: average tree growth rates are positively related toHmax, while wood density and the initial allometric slope of (species‐specific)H–Drelationships are negatively related toHmax. These patterns may be explained by an association of low light levels with slow growth and high density wood in understory species; the latter property may in turn allow for relatively high allometric slopes ofH–Drelationships in saplings of small‐statured species. Analyses that control for phylogenetic differences provide evidence that such interspecific allometric patterns are the product of convergent evolution. These results are consistent with the idea that much ecological variation within species‐rich taxa of southeast Asian rain forest trees is related to differentiation along a vertical axis of tree size.
Plant–pollinator interactions in the understory of a lowland mixed dipterocarp forest in Sarawak
Authors: Kato Makoto
Published: January 2018

Pollination biology of 41 plants species of 21 families blooming in the forest understory was investigated in a lowland mixed diplerocarp forest in Lambir Hills National Park, Sarawak. Among these species, 29 species (71%) were pollinated by bees, four (10%) by nectariniid birds, three by small dipterans, and others by moths, butterflies, syrphid flies, wasps, and beetles. The 29 bee‐pollinated species consisted of five distinct pollination guilds: ten species pollinated by medium traplining bees (two Amegilla species), nine by small traplining bees (three halictid and a xylocopine species), two by stingless bees and beetles, seven by stingless bees, and one by megachilid bees. The bees constituting the first two guilds were shade‐loving, swiftly flying, long‐tongued trapliners. Proboscis lengths of these pollinators correlated with flower depth of the host plant. Pollination systems in the forest understory were distinguished from that in the canopy by the prevalence of specific interactions, the number of traplining solitary bees, and lack of pollination systems by mass‐recruiting eusocial bees, large Xylocopa bees, thrips, bats, and wind. These characteristics are largely similar between the Palaeotropics and the Neotropics through convergence of nectarivorous birds (spiderhunters vs. hummingbirds) and traplining bees (Amegilla vs. euglossine bees).
Phylogenetic reticulation in subtribe Helianthinae
Authors: Schilling Edward E. , Panero Jose L.
Published: January 2018

Incongruence between phylogenetic estimates based on nuclear and chloroplast DNA (cpDNA) markers was used to infer that there have been at least two instances of chloroplast transfer, presumably through wide hybridization, in subtribe Helianthinae. One instance involved Simsia dombeyana, which exhibited a cpDNA restriction site phenotype that was markedly divergent from all of the other species of the genus that were surveyed but that matched the restriction site pattern previously reported for South American species of Viguiera. In contrast, analysis of sequence data from the nuclear ribosomal DNA internal transcribed spacer (ITS) region showed Simsia to be entirely monophyletic and placed samples of S. dombeyana as the sister group to the relatively derived S. foetida, a result concordant with morphological information. A sample of a South American species of Viguiera was placed by ITS sequence data as the sister group to a member of V. subg. Amphilepis, which was consistent with cpDNA restriction site data. Samples of Tithonia formed a single monophyletic clade based on ITS sequence data, whereas they were split between two divergent clades based on cpDNA restriction site analysis. The results suggested that cpDNA transfer has occurred between taxa diverged to the level of morphologically distinct genera, and highlight the need for careful and complete assessment of molecular data as a source of phylogenetic information.
Systematic significance of pollen arrangement in MICROSPORANGIA OF POACEAE AND Cyperaceaei REVIEW AND OBSERVATIONS ON REPRESENTATIVE TAX A
Authors: Kirpes Christine C. , Clark Lynn G. , Lersten Nels R.
Published: January 2018

An anatomical survey of anthers of the Poaceae and Cyperaceae and two related families, the Restionaceae and Flagellariaceae, was conducted to determine the taxonomic distribution and possible phylogenetic significance of pollen arrangement. An unusual pollen arrangement was known from a small number of taxa in the Poaceae and Cyperaceae, in which a single, uniseriate cylinder of pollen grains is arranged in the anther locule such that each grain is in contact with the tapetum (termed here “peripheral” pollen). This contrasts with the prevailing arrangement in other angiosperms in which the locule contains a relatively large number of pollen grains in no special configuration, with many interior grains that never touch the tapetum (termed here “central” pollen). A total of 48 species in these four families was examined in this study, and observations on pollen arrangement for numerous additional species in these families were gleaned from the literature. We confirm that the peripheral arrangement is predominant in Poaceae and Cyperaceae, although both families also include species with central pollen, whereas only central pollen is found in Restionaceae and Flagellariaceae. In the peripheral arrangement, the pore of the pollen grain or pseudomonad, when observed, is in contact with the tapetum, but it has not been definitively demonstrated that this is always the case. Peripheral pollen in the Poaceae and Cyperaceae is nonhomologous because of the presence of pseudomonads in the latter family. It remains unexplained why peripherally arranged pollen or pseudomonads, with the attendant reduction in the number of pollen grains, should be associated with anemophily in these two families.
Floral display and pollination success in Senecio jacobaea (Asteraceae): Interactive effects of head and corymb size
Authors: Andersson Stefan
Published: January 2018

The self‐sterile Senecio jacobaea (Asteraceae) presents its rayed heads in large, compound inflorescences (corymbs). I examined the role of head and corymb size in pollinator attraction, and whether the positive effect of intact rays (if any) depends on the size of the corymb. Using female fertility as a measure of pollination success, I assessed the performance of stems representing four experimentally produced character combinations: (1) few heads without rays, (2) many heads without rays, (3) few heads with rays, and (4) many heads with rays. The proportion of flowers setting fruit was higher for intact stems (treatments 2, 4) than for stems on which the majority of the heads had been removed (treatments 1, 3), suggesting selection for maximum inflorescence production. By contrast, experimental removal of all rays had a relatively weak negative effect on fruit set, with few‐headed stems (treatment 1) experiencing a greater reduction than stems with many heads (treatment 2). These results suggest that clusters of heads produce a synergistic effect on pollinator attraction, allowing plants to maintain high visitation rates even if there are drastic reductions in the basic attraction units. Hence, the number of heads and the attractiveness of the individual heads interacted in their effect on pollination success. Fruit set per flower differed greatly between sites and was positively correlated with plant density.
Morphological and physiological responses of Scaevola sericea (Goodeniaceae) seedlings to salt spray and substrate salinity
Authors: Alpha Christopher G. , Drake Donald R. , Goldstein Guillermo
Published: January 2018

The effects of substrate salinity and salt spray upon seedlings of Scaevola sericea were examined in this study. Three levels of substrate salinity: 0.0 ppt, 3.0 ppt, and 10.0 ppt were examined in conjunction with three levels of salt spray: zero, medium (200 mg m‐2mdd‐1), and high (1200–1500 mg‐m‐2mdd‐1). Leaf surface area, root to shoot ratio, as well as leaf, stem, and root mass decreased significantly (P 0.05) with increasing substrate salinity. Biomass accumulation was very low at 10.0 ppt substrate salinity, suggesting that higher levels of substrate salinity cannot be tolerated by the seedlings. Salt spray had a substantial effect on several of these variables, however its effects were less pronounced than those of substrate salinity. Cell sap osmolarity, leaf thickness, and leaf specific mass increased significantly (P 0.05) with both increasing substrate salinity and salt spray levels. Leaf carbon isotope ratios (δl3C) became more positive with increasing salinity, indicating an enhancement of the intrinsic water use efficiency of the seedlings at higher salinities. Scaevola sericea is one of the dominant plants found at the leading edge of strand communities in the Hawaiian archipelago and throughout much of the tropical Pacific. Since substrate salinity and salt spray increase with proximity to the ocean, the two factors may act together to limit the seaward expansion of S. sericea in coastal habitats.
The immunolocalization of plasma membrane H+‐ATPase in the transfer cell region of Brassica napus (Brassicaceae) ovules
Authors: Van Caeseele L. , Klingner B. , Sumner M. J.
Published: January 2018

Unfertilized mature ovules of Brassica L. contain an abundance of starch in the integument cells from the micropyle to a plane approximately at the level of the central cell polar nuclei. Inside the embryo sac central cell, in the coinciding region, there are transfer cell‐like wall projections with plasma membranes appressed to their inner surfaces. H+‐ATPase is present along the inner surfaces of the wall projections as indicated by reactivity with antibody raised against plasma membrane H+‐ATPase. A number of mitochondria are in close association with wall projections in the region of the egg apparatus. Antibody raised against corn plasma membrane H+‐ATPase cross reacts with a protein of the same size in extracts of Brassica napus indicating that the two species contain a similar plasma membrane H+‐ATPase.
Compound C induces protective autophagy in human cholangiocarcinoma cells via Akt/mTOR‐independent pathway
Authors: Zhao Xiaofang , Luo Guosong , Cheng Ying , Yu Wenjing , Chen Run , Xiao Bin , Xiang Yuancai , Feng Chunhong , Fu Wenguang , Duan Chunyan , Yao Fuli , Xia Xianming , Tao Qinghua , Wei Mei , Dai Rongyang
Published: January 2018

Compound C, a well‐known inhibitor of AMP‐activated protein kinase (AMPK), has been reported to exert antitumor activities in some types of cells. Whether compound C can exert antitumor effects in human cholangiocarcinoma (CCA) remains unknown. Here, we demonstrated that compound C is a potent inducer of cell death and autophagy in human CCA cells. Autophagy inhibitors increased the cytotoxicity of compound C towards human CCA cells, as confirmed by increased LDH release, and PARP cleavage. It is notable that compound C treatment increased phosphorylated Akt, sustained high levels of phosphorylated p70S6K, and decreased mTOR regulated p‐ULK1 (ser757). Based on the data that blocking PI3K/Akt or mTOR had no apparent influence on autophagic response, we suggest that compound C induces autophagy independent of Akt/mTOR signaling in human CCA cells. Further study demonstrated that compound C inhibited the phosphorylation of JNK and its target c‐Jun. Blocking JNK by SP600125 or siRNA suppressed autophagy induction upon compound C treatment. Moreover, compound C induced p38 MAPK activation, and its inhibition promoted autophagy induction via JNK activation. In addition, compound C induced p53 expression, and its inhibition attenuated compound C‐induced autophagic response. Thus, compound C triggers autophagy, at least in part, via the JNK and p53 pathways in human CCA cells. In conclusion, suppresses autophagy could increase compound C sensitivity in human CCA.
Frenkel‐exciton decomposition analysis of circular dichroism and circularly polarized luminescence for multichromophoric systems
Authors: Shiraogawa Takafumi , Ehara Masahiro , Jurinovich Sandro , Cupellini Lorenzo , Mennucci Benedetta
Published: January 2018

Recently, a method to calculate the absorption and circular dichroism (CD) spectra based on the exciton coupling has been developed. In this work, the method was utilized for the decomposition of the CD and circularly polarized luminescence (CPL) spectra of a multichromophoric system into chromophore contributions for recently developed through‐space conjugated oligomers. The method which has been implemented using rotatory strength in the velocity form and therefore it is gauge‐invariant, enables us to evaluate the contribution from each chromophoric unit and locally excited state to the CD and CPL spectra of the total system. The excitonic calculations suitably reproduce the full calculations of the system, as well as the experimental results. We demonstrate that the interactions between electric transition dipole moments of adjacent chromophoric units are crucial in the CD and CPL spectra of the multichromophoric systems, while the interactions between electric and magnetic transition dipole moments are not negligible. © 2018 Wiley Periodicals, Inc.
Recent Advances in Imidazo[5,1‐f][1,2,4]triazin‐4(3H)‐ones Chemistry: An Overview of the Synthetic Routes to Vardenafil and Its Analogues
Authors: Gouda Moustafa A.
Published: January 2018

The biological and medicinal properties of imidazo[5,1‐f][1,2,4]triazin‐4(3H)‐ones and its analogues have prompted enormous research aimed at developing synthetic routes to these heterocycles. This review focuses on the chemical properties associated with these systems.
Ultrasound‐assisted Synthesis of Novel Pyrazole and Pyrimidine Derivatives as Antimicrobial Agents
Authors: Dofe Vidya S. , Sarkate Aniket P. , Shaikh Zarina M. , Jadhav Chetan K. , Nipte Amol S. , Gill Charansingh H.
Published: January 2018

Herein, we report a convenient and facile methodology for the synthesis of new series of pyrazole and pyrimidine derivatives 2a–f and 3a–f under ultrasound irradiation. Pyrazole and pyrimidine derivatives have been synthesized in better yields and shorter reaction times compared with the conventional method. The chemical structures of all the synthesized compounds were elucidated by their IR, 1H NMR, 13C NMR, MS, and elemental analysis. Further, the target compounds were screened for their antimicrobial activity against four bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa) and two fungi (Candida albicans, Aspergillus niger). In particular, compounds 2a, 2d, 2e, 3a, 3e, and 3f exhibited potent antimicrobial activity.
Electron microscopic characterization of nuclear egress in the sea urchin gastrula
Authors: LaMassa Nicole , Arenas‐Mena Cesar , Phillips Greg R.
Published: January 2018

Nuclear egress, also referred to as nuclear envelope (NE) budding, is a process of transport in which vesicles containing molecular complexes or viral particles leave the nucleus through budding from the inner nuclear membrane (INM) to enter the perinuclear space. Following this event, the perinuclear vesicles (PNVs) fuse with the outer nuclear membrane (ONM), where they release their contents into the cytoplasm. Nuclear egress is thought to participate in many functions such as viral replication, cellular differentiation, and synaptic development. The molecular basis for nuclear egress is now beginning to be elucidated. Here, we observe in the sea urchin gastrula, using serial section transmission electron microscopy, strikingly abundant PNVs containing as yet unidentified granules that resemble the ribonucleoprotein complexes (RNPs) previously observed in similar types of PNVs. Some PNVs were observed in the process of fusion with the ONM where they appeared to release their contents into the cytoplasm. These vesicles were abundantly observed in all three presumptive germ layers. These findings indicate that nuclear egress is likely to be an important mechanism for nucleocytoplasmic transfer during sea urchin development. The sea urchin may be a useful model to characterize further and gain a better understanding of the process of nuclear egress.
Homogeneity analysis of wind data from 213 m high Cabauw tower
Authors: Petrović Predrag , Romanic Djordje , Ćurić Mladjen
Published: January 2018

Homogeneous meteorological data are a prerequisite for reliable climatological studies. This paper investigates the homogeneity of wind data from 213 m high Cabauw tower located in The Netherlands. The wind measurements are conducted at 10, 20, 40, 80, 140 and 200 m above ground. The analysed data cover the period from February 1986 to January 1997 and from April 2000 to December 2015. This study presents the first homogeneity analysis of wind data from a tall meteorological mast. Homogeneities of wind speed and wind direction series were investigated independently using the ReDistribution Method. Overall, the wind measurements at Cabauw tower are very homogeneous. The only wind speed inhomogeneity was detected at 200 m above ground and it seems to be, at least to a certain extent, caused by the rapid expansion of the town of Lopik in the 1990s. Lopik's growth to the west, however, only influenced the east winds on the Cabauw tower. Small inhomogeneities in wind direction data were detected at 20, 40 and 80 m levels, whereas a fairly large inhomogeneity was observed at 10 m above ground. Several potential causes of inhomogeneities in wind direction data are discussed, but the major contributor could not be determined with certainty. In addition, the homogeneity of real measurements from Cabauw tower is compared against the synthetically created wind data for Cabauw tower using the Monte‐Carlo method of random sampling. The results show that the detected anomalies are not due to the random noise in the time series.
Strategies to Reduce Catheter‐Related Bloodstream Infections in Pediatric Patients Receiving Home Parenteral Nutrition: The Efficacy of Taurolidine‐Citrate Prophylactic‐Locking
Authors: Lambe Cecile , Poisson Catherine , Talbotec Cecile , Goulet Olivier
Published: January 2018

Background

Catheter‐related bloodstream infections (CRBSIs) remain a major issue in patients who are receiving home parenteral nutrition (HPN). The aim of this interventional study was to assess the impact of a new strategy using taurolidine‐citrate (T‐C) prophylactic locks on the CRBSI rate in children with intestinal failure who are receiving HPN.

Methods

The rate of CRBSIs was monitored every calendar year in a prospective cohort of 195 children with intestinal failure. T‐C locks were initiated from October 2011 in children with recurring CRBSIs (≥2 episodes per year).

Results

In the whole cohort, the median annual CRBSI rate per 1000 catheter days decreased significantly from 2.07 in 2008 to 2010 to 1.23 in 2012 to 2014 (P < .05). T‐C locks were used in 40 patients. No adverse events were reported. In taurolidine‐treated patients, the CRBSI rate per 1000 catheter days decreased from 4.16 to 0.25 (P < .0001). The cumulative percentage of patients free of CRBSI at 18 months was 92% (95% confidence interval [CI]: 71–98) on T‐C lock vs 61% (95% CI: 49–72) in controls (P = .01). In multivariate analysis, factors associated with CRBSI were immune deficiency (adjusted hazard ratio 3.49; 95% CI: 1.01–12.17) and the young age of the parents (adjusted hazard ratio 4.79, 95% CI: 2.16–10.62), whereas T‐C locks were protective (adjusted hazard ratio 0.22, 95% CI: 0.06–0.74).

Conclusion

This study confirms the efficacy of T‐C catheter locks in decreasing the incidence of CRBSIs in children with intestinal failure who are receiving HPN.
Eating jellyfish: safety, chemical and sensory properties
Authors: Raposo António , Coimbra Alice , Amaral Luís , Gonçalves Amparo , Morais Zilda
Published: January 2018

BACKGROUND

People's preference for fish with a high trophic level, like Atlantic cod and tuna, leads to a large food footprint. Responsible seafood consumption should include underutilised local products; hence the culinary use of edible jellyfish can be an effective contribution. The present work focused on Catostylus tagi to contribute to the consumption of edible jellyfish in the West.

RESULTS

A questionnaire conducted with 192 young people showed an interest in tasting jellyfish‐based food (64.6%). The resulting product, obtained by an alternative cooking process to traditional Asian ones, was chemically characterised and underwent microbiological and heavy metals control. The results indicated its non‐toxicity. Patients who were allergic to seafood as well as non‐allergic volunteers revealed no allergic reaction to the jellyfish umbrella product (intakes up to 5 mg/kg body weight and 8 mg/kg, respectively). Seafood‐trained panellists defined the product's main impact on the mouth as freshness (72 mg/kg body weight). The preliminary snack, a pâté, was positively accepted by allergic (7 in 9; n = 20) and non‐allergic volunteers (6 in 7; n = 21).

CONCLUSION

The present study confirmed that jellyfish intake is safe, even for allergic individuals, and its organoleptic properties were accepted by the study population. © 2018 Society of Chemical Industry
Preparative isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. using supercritical fluid extraction combined with consecutive high‐speed countercurrent chromatography
Authors: Yan Rongwei , Shen Jie , Liu Xiaojing , Zou Yong , Xu Xinjun
Published: January 2018

The objective of this study was to develop a consecutive preparation method for the isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. The process involved supercritical fluid extraction with CO2, solvent extraction, and two‐step high‐speed countercurrent chromatography. Pressure, temperature, and the volume of entrainer were optimized as 27 MPa, 52°C, and 60 mL by response surface methodology in supercritical fluid extraction with CO2, and the yield of the crude extracts was 7.91 g from 100 g of leaves. Subsequently, 80% methanol/water was used to extract and condense the three compounds from the crude extracts, and 4.23 g of methanol/water extracts was obtained. Then, a two‐step high‐speed countercurrent chromatography procedure was developed for the isolation of the three target compounds from methanol/water extracts, including conventional high‐speed countercurrent chromatography for further enrichment and consecutive high‐speed countercurrent chromatography for purification. The yield of concentrates from high‐speed countercurrent chromatography was 2.50 g from 4.23 g of methanol/water extracts. Finally, the consecutive high‐speed countercurrent chromatography produced 103.2 mg of hainanmurpanin, 244.7 mg of meranzin, and 255.4 mg of phebalosin with purities up to 97.66, 99.36, and 98.64%, respectively, from 900 mg of high‐speed countercurrent chromatography concentrates in one run of three consecutive sample loadings without exchanging a solvent system.
A Comparison of Electric‐Field‐Driven and Pressure‐Driven Fiber Generation Methods for Drug Delivery
Authors: Ahmed Jubair , Matharu Rupy Kaur , Shams Talayeh , Illangakoon Upulitha Eranka , Edirisinghe Mohan
Published: January 2018

Polymeric fibers are prepared by using electric field driven fiber production technology—electrospinning and pressure driven fiber production technology—pressurized gyration. Fibers of four different polymers: polyvinylidene fluoride (PVDF), poly(methyl methacrylate (PMMA), poly(N‐isopropylacrylamide), and polyvinylpyridine (PVP), are spun by both techniques and differences are analyzed for their suitability as drug carriers. The diameters of electrospun fibers are larger in some cases (PVDF and PMMA), producing fibers with lower surface area. Pressurized gyration allows for a higher rate of fiber production. Additionally, drug‐loaded PVP fibers are prepared by using two poorly water‐soluble drugs (Amphotericin B and Itraconazole). In vitro dissolution studies show differences in release rate between the two types of fibers. Drug‐loaded gyrospun fibers release the drugs faster within 15 min compared to the drug‐loaded electrospun fibers. The findings suggest pressurized gyration is a promising and scalable approach to rapid fiber production for drug delivery when compared to electrospinning.
Coupling nonlinear beams and continua: Variational principles and finite element approximations
Authors: Romero Ignacio
Published: January 2018

Two variational principles are proposed that describe equilibrium problems with connected nonlinear beams and solids. The principles extend the classical principle of minimum potential energy for beams and deformable bodies incorporating constraints that weakly enforce the beam kinematics at the common interface using either Lagrange multipliers or penalty terms. In contrast with existing alternatives, in the new approach, the surfaces of bodies connected to beams can deform in an energetically optimal way while globally behaving as beam cross sections. This allows, eg, warping and Poisson effects in beam/solid interfaces. Finite element implementations of the new principles are described in detail and application examples are provided that illustrate their use.
Regiochemical Control in Triptycene Formation—An Exercise in Subtle Balancing Multiple Factors
Authors: Lamm Jan‐Hendrik , Vishnevskiy Yury V. , Ziemann Eric , Neumann Beate , Stammler Hans‐Georg , Mitzel Norbert W.
Published: January 2018

Reactions between 1,8‐dichloroanthracenes with substituents in position 10 andortho‐chloroaryne afford mixtures of 1,8,13‐ (syn) and 1,8,16‐trichlorotriptycenes (anti). Thesyn/antiratio is dependent on these substituents. Electropositive substituents like SiMe3and GeMe3lead to preferred formation of thesyn‐isomer, whereas CMe3groups exclusively afford theanti‐isomer. Different quantum chemical calculations including location of transition states give conflicting results, but indicate the importance of dispersion forces for an at least qualitative prediction of results. Thesyn‐trichlorotriptycenes with SiMe3and GeMe3substituents were characterized by using NMR spectroscopy, mass spectrometry, and X‐ray diffraction experiments.
Development of the “Day 100 Talk”: Addressing existing communication gaps during the early cancer treatment period in childhood cancer
Authors: Feraco Angela M. , Brand Sarah R. , Gagne Joshua , Sullivan Amy , Block Susan D. , Wolfe Joanne
Published: January 2018

Background

Families’ communication needs during the early cancer treatment period (ECTP) may not be optimally met by current practices. We sought to identify potential communication gaps and to ameliorate these by developing a novel in‐depth conversation between families and their pediatric oncologists, the “Day 100 Talk” (D100), during the ECTP.

Procedure

We conducted semistructured interviews with parents and patients undergoing childhood cancer treatment for < 7 months. Interviews sought to elicit perceived communication gaps regarding cancer care and inform D100 development. Following qualitative analysis of interview responses, we developed a three‐part D100 conversation tool consisting of a preparatory family worksheet, a conversation guide, and a family summary sheet. We presented the tool during interviews and a focus group with pediatric oncology providers and revised it to incorporate provider input.

Results

Twenty‐two stakeholders (six parents, five adolescents, and 11 providers) participated in interviews or a focus group. Parents and patients perceived insufficient anticipatory guidance as the most important communication gap. They also reported sometimes withholding worries and cancer‐related beliefs. Meanwhile, oncology providers worried about “opening Pandora's Box” and limited clinical time. Additionally, providers reported employing indirect methods such as surmising to determine families’ needs and relying on psychosocial clinicians to engage families around potentially “taboo” issues of emotional coping and spirituality.

Conclusion

Creating a communication occasion (D100), ensuring complementary disciplinary expertise through joint participation by oncologists and psychosocial clinicians, and providing a conversation tool to prompt disclosure by families and facilitate anticipatory guidance may ameliorate existing communication gaps during the ECTP.
Structural and optical properties of soluble melanin analogues with enhanced photoluminescence quantum efficiency
Authors: Paulin João Vitor , Veiga Amanda Garcez , Garcia‐Basabe Yunier , Rocco Maria Luiza Miranda , Graeff Carlos FO
Published: January 2018

Melanin is a functional material of growing interest for bioelectronics. Several melanin analogues have been employed in order to fully explore its potential; in this work melanin was synthesized using dimethylsulfoxide (DMSO) and O2 under pressure as oxidizing agent. It is shown that the products have similar functional groups and solubility; however, O2 pressure produces more carboxylated structures and improves the synthesis reaction rate. The photoluminescence of all sulfonated melanin analogues was studied. It is shown that the material synthesized in DMSO has photoluminescence in the visible region (487 nm) with a quantum yield of (2.12 ± 0.02)%. This good quantum yield compared to natural and synthetic melanin may open new perspectives for its use in optoelectronics applications. The origin of this effect is discussed in terms of the polymer structure. © 2018 Society of Chemical Industry
A Review on Ge Nanocrystals Embedded in SiO2 and High‐k Dielectrics
Authors: Lehninger David , Beyer Jan , Heitmann Johannes
Published: January 2018

In this article, the work on Ge nanocrystals embedded in dielectric films formed by phase separation from supersaturated solid solutions is reviewed. Different methods to synthesize supersaturated solid solutions are covered, e.g., magnetron sputtering, ion implantation, and chemical vapor deposition. The phase separation is activated by subsequent high temperature annealing. Important parameters that influence the formation and properties of the Ge nanocrystals are discussed. Various matrix materials like SiO2, Al2O3, HfO2, HfAlOx, Lu2O3, ZrO2, TaZrOx, and Si3N4 are reported in the literature. The influence of the matrix on the formation and properties of the Ge nanocrystals is addressed in this review. Ge nanocrystals are investigated for applications such as charge storage nodes in nonvolatile memory devices or as silicon technology compatible light emitters. A key to establish these applications seems to be embedding the Ge nanocrystals in still amorphous matrices. This could help to avoid grain boundaries that act as leakage paths for electrical charges (unfavorable for nonvolatile memories) and facilitate defects, which could act as recombination centers (unfavorable for light emitters). A further important point is the synthesis of size and position controlled Ge nanocrystals. Both aspects are reviewed for Ge nanocrystals embedded in the mentioned matrix materials.
A new approximation technique for resource‐allocation problems
Authors: Saha Barna , Srinivasan Aravind
Published: January 2018

We develop a rounding method based on random walks in polytopes, which leads to improved approximation algorithms and integrality gaps for several assignment problems that arise in resource allocation and scheduling. In particular, it generalizes the work of Shmoys and Tardos on the generalized assignment problem to the setting where some jobs can be dropped. New concentration bounds for random bipartite matching are developed as well.
Long‐term material and structural behavior of high‐strength concrete cantilever bridge: Results of 20 years monitoring
Authors: Lantsoght Eva O. L. , van der Veen Cor , de Boer Ane , van der Ham Herbert
Published: January 2018

In 1997, the Second Stichtse Bridge was built in the Netherlands using the balanced cantilever method. The use of high‐strength concrete was proposed. At that time, the long‐term behaviour of this material was not known, and no code provisions were applicable. Therefore, it was proposed to monitor the material behaviour and the deflections of the bridge. To evaluate the development of the concrete compressive strength and the concrete splitting tensile strength over time, concrete cubes were cast at the same time as each of the cantilever segments, and stored inside the bridge. These samples have been tested at different points in time to study the development of the strength as a function of the elapsed time. Creep and shrinkage measurements were carried out on samples stored inside the bridge as well as in the laboratory. Temperature and moisture were monitored as well. The deflections of the bridge superstructure have been measured periodically. These measurements can be compared to predictions from finite element models. Based on the available data, it is found that the concrete compressive and splitting tensile strength remain constant. The deflections are small, and the advanced finite element models resulted in good predictions.