238 research outputs found
Measurement of in situ monomer sorption in polyu(propylene)
An experimental method has been developed to compare the amount of monomer absorbed in freshly produced poly(propylene) with the amount of monomer absorbed in the same material after degassing. It has been found that propylene sorption in freshly produced poly(propylene) is significantly higher than the sorption in the same but degassed polymer. The difference depends on the degree of drying and is time-dependent. This fact can be an explanation for reduced activity often observed in the transition from liquid- to gas-phase polymerization
Identifizierung der Realstrukturen im System VOHPO<sub>4</sub> x 0.5 H<sub>2</sub>O - (VO)<sub>2</sub>P<sub>2</sub>O<sub>7</sub>
Vanadylpyrophosphate werden seit langer Zeit in der selektiven Partialoxidation von n-Butan zu Maleinsäureanhydrid (MSA) eingesetzt. Entscheidend für die katalytische Aktivität sowie Selektivität gegenüber MSA ist der Syntheseweg des Precursors VOHPO4 x 0.5 H2O sowie des durch Kalzinierung erhaltenen Vanadylpyrophosphates (VO)2P2O7 [1, 2]. Ziel dieser Untersuchungen ist es, einen Beitrag zum fundamentalen Verständnis der Struktur – Wirkungsbeziehung dieser Katalysatoren in der Partialoxidation zu liefern. Hierzu wurde eingehend die Realstruktur, d.h. Defektarten wie Atompositionen und Besetzungszahlen sowie Kristallitmorphologien und Mikrospannungen in der Verbindung (VO)2P2O7 untersucht
Pragmatism, moral responsibility or policy change: the Syrian refugee crisis and selective humanitarianism in the Turkish refugee regime
Cytoplasmic genome substitution in wheat affects the nuclear-cytoplasmic cross-talk leading to transcript and metabolite alterations
Abstract Background Alloplasmic lines provide a unique tool to study nuclear-cytoplasmic interactions. Three alloplasmic lines, with nuclear genomes from Triticum aestivum and harboring cytoplasm from Aegilops uniaristata, Aegilops tauschii and Hordeum chilense, were investigated by transcript and metabolite profiling to identify the effects of cytoplasmic substitution on nuclear-cytoplasmic signaling mechanisms. Results In combining the wheat nuclear genome with a cytoplasm of H. chilense, 540 genes were significantly altered, whereas 11 and 28 genes were significantly changed in the alloplasmic lines carrying the cytoplasm of Ae. uniaristata or Ae. tauschii, respectively. We identified the RNA maturation-related process as one of the most sensitive to a perturbation of the nuclear-cytoplasmic interaction. Several key components of the ROS chloroplast retrograde signaling, together with the up-regulation of the ROS scavenging system, showed that changes in the chloroplast genome have a direct impact on nuclear-cytoplasmic cross-talk. Remarkably, the H. chilense alloplasmic line down-regulated some genes involved in the determination of cytoplasmic male sterility without expressing the male sterility phenotype. Metabolic profiling showed a comparable response of the central metabolism of the alloplasmic and euplasmic lines to light, while exposing larger metabolite alterations in the H. chilense alloplasmic line as compared with the Aegilops lines, in agreement with the transcriptomic data. Several stress-related metabolites, remarkably raffinose, were altered in content in the H. chilense alloplasmic line when exposed to high light, while amino acids, as well as organic acids were significantly decreased. Alterations in the levels of transcript, related to raffinose, and the photorespiration-related metabolisms were associated with changes in the level of related metabolites. Conclusion The replacement of a wheat cytoplasm with the cytoplasm of a related species affects the nuclear-cytoplasmic cross-talk leading to transcript and metabolite alterations. The extent of these modifications was limited in the alloplasmic lines with Aegilops cytoplasm, and more evident in the alloplasmic line with H. chilense cytoplasm. We consider that, this finding might be linked to the phylogenetic distance of the genomes.The authors thank Prof. S.S. Maan (North Dakota State University, USA) for providing the alloplasmic lines T183 and T195 and Dr. Alessio Aprile (University of Salento, Lecce, Italy) for help in data analysis. LQ was partly supported by grant # 2770367, the Chief Scientist Fund, the Ministry of Agriculture, Israel.Peer Reviewe
The Effect of Polyhydramnios on Cervical Length in Twins: A Controlled Intervention Study in Complicated Monochorionic Pregnancies
Objective: To test the hypothesis that cervical shortening in polyhydramnios reflects the degree of excess amniotic fluid, and increases with normalisation of amniotic fluid volume. Study Design: Prospective cohort study of 40 women with monochorionic twins undergoing interventional procedures between 16-26 weeks. Cervical length was assessed via transvaginal sonography pre-procedure, 1 and 24 hours postprocedure, and results compared between amnioreduction and control procedures. Amniotic fluid index (AFI) was measured pre- and post-procedure. Results: Pre-procedural cervical length correlated with AFI (linear fit = 5.07 -0.04x, R2 = 0.17, P = 0.03) in patients with polyhydramnios (n = 28). Drainage of 2000ml fluid (range 700-3500ml), reduced AFI from 42cm to 21cm (P>0.001). Their pre-procedural cervical length did not change at one (mean Δ:-0.1cm, 95%CI, -0.4 to 0.2) or 24 hours (0.2cm, -0.1 to 0.6) after amnioreduction. There was no change in cervical length at control procedures. Conclusion: Cervical shortening in twins with polyhydramnios does not appear to be an acute process; cervical length can be measured before or after therapeutic procedures. © 2008 Engineer et al
Пролиферация и апоптоз лимфоцитов в ответ на стимуляцию боррелиозным антигеном у больных иксодовым клещевым боррелиозом
The object of this work was to study the correlation between the lymphocyte proliferation and apoptosis in the cultures stimulated by specific inactivated Borrelia garinii antigen and the different clinical outcomes in Lyme borreliosis patients. It was found that borrelia antigen stimulation of the cultures obtained from chronic patients induced T helper type 1-like response as well as depression in lymphocyte apoptosis, which may provide the basis of persistent activated T cell immune response and chronic inflammatory in Lyme borreliosis.Цель настоящей работы заключалась в определении взаимосвязи между особенностями пролиферации и апоптоза клеток в культурах лимфоцитов, стимулированных специфическим антигеном B. garinii, и развитием различных клинических исходов у больных иксодовым клещевым боррелиозом (ИКБ). Установлено, что стимуляция боррелиозным антигеном культур, полученных от больных хроническим ИКБ, приводит к развитию in vitro Т-хелперов типа 1 при одновременном подавлении апоптоза реактивных клеток, что может лежать в основе формирования персистентно активированного Т-клеточного иммунного ответа и хронического воспалительного процесса при этом заболевании
Metabolomics Reveals Target and Off-Target Toxicities of a Model Organophosphate Pesticide to Roach (Rutilus rutilus): Implications for Biomonitoring
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Gene expression atlas of fruit ripening and transcriptome assembly from RNA-seq data in octoploid strawberry (Fragaria × ananassa)
RNA-seq has been used to perform global expression analysis of the achene and the receptacle at four stages of fruit ripening, and of the roots and leaves of strawberry (Fragaria × ananassa). About 967 million reads and 191 Gb of sequence were produced, using Illumina sequencing. Mapping the reads
in the related genome of the wild diploid Fragaria vesca revealed differences between the achene and receptacle development program, and reinforced the role played by ethylene in the ripening receptacle. For the strawberry transcriptome assembly, a de novo strategy was followed, generating separate assemblies for each of the ten tissues and stages sampled. The Trinity program was used for these assemblies, resulting in over 1.4 M isoforms. Filtering by a threshold of 0.3 FPKM, and doing Blastx (E-value < 1 e-30) against the UniProt database of plants reduced the number to 472,476 isoforms. Their assembly with the MIRA program (90% homology) resulted in 26,087 contigs. From these,
91.34 percent showed high homology to Fragaria vesca genes and 87.30 percent Fragaria iinumae (BlastN E-value < 1 e-100). Mapping back the reads on the MIRA contigs identified polymorphisms at nucleotide level, using FREEBAYES, as well as estimate their relative abundance in each sample
(Homo)glutathione Deficiency Impairs Root-knot Nematode Development in Medicago truncatula
Root-knot nematodes (RKN) are obligatory plant parasitic worms that establish and maintain an intimate relationship with their host plants. During a compatible interaction, RKN induce the redifferentiation of root cells into multinucleate and hypertrophied giant cells essential for nematode growth and reproduction. These metabolically active feeding cells constitute the exclusive source of nutrients for the nematode. Detailed analysis of glutathione (GSH) and homoglutathione (hGSH) metabolism demonstrated the importance of these compounds for the success of nematode infection in Medicago truncatula. We reported quantification of GSH and hGSH and gene expression analysis showing that (h)GSH metabolism in neoformed gall organs differs from that in uninfected roots. Depletion of (h)GSH content impaired nematode egg mass formation and modified the sex ratio. In addition, gene expression and metabolomic analyses showed a substantial modification of starch and γ-aminobutyrate metabolism and of malate and glucose content in (h)GSH-depleted galls. Interestingly, these modifications did not occur in (h)GSH-depleted roots. These various results suggest that (h)GSH have a key role in the regulation of giant cell metabolism. The discovery of these specific plant regulatory elements could lead to the development of new pest management strategies against nematodes
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