40 research outputs found

    Synthesis of Phosphine Trans-Substituted Derivatives of Iron Pentacarbonyl

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    The synthesis of trans-Fe (CO)3(PR3)2 (PR3 = PPh3, PPh2Me, PPh2CHCH2, P(c-C6H11)3, P(n-C4H9)3, PPh2H) can be achieved by refluxing iron pentacarbonyl under reducing conditions in the presence of ligand in 1-butanol. Addition of iron pentacarbonyl to a 1-butanol solution of sodium borohydride at room temperature results in a quantitative conversion of the iron carbonyl complex to the corresponding mononuclear formyl complex. Upon heating the initially formed formyl species decomposes to form the tetracarbonylhydridoferrate(0) anion . This hydride is believed to undergo reaction with the phosphine ligand to yield the isolated trans-substituted iron complex. Even though traces of monosubstituted product were detected in the crude reaction mixture by infrared spectroscopy, uncontaminated trans-substituted complexes were isolated after crystallization from dichloromethane/methanol. All complexes have been found to be sensitive to oxygen if in solution, with the rate of decomposition depending on the kind of ligand. However, if they are dry and under vacuum no apparent decomposition takes place. All synthesized complexes have been characterized by IR spectroscopy, 31P NMR, and by their melting points. The value of the presented synthesis is based on its high selectivity, extremely short reaction time, good to very good yields, and its simplicity

    Synthesis of Phosphine Trans-Substituted Derivatives of Iron Pentacarbonyl

    Get PDF
    The synthesis of trans-Fe (CO)3(PR3)2 (PR3 = PPh3, PPh2Me, PPh2CHCH2, P(c-C6H11)3, P(n-C4H9)3, PPh2H) can be achieved by refluxing iron pentacarbonyl under reducing conditions in the presence of ligand in 1-butanol. Addition of iron pentacarbonyl to a 1-butanol solution of sodium borohydride at room temperature results in a quantitative conversion of the iron carbonyl complex to the corresponding mononuclear formyl complex. Upon heating the initially formed formyl species decomposes to form the tetracarbonylhydridoferrate(0) anion . This hydride is believed to undergo reaction with the phosphine ligand to yield the isolated trans-substituted iron complex. Even though traces of monosubstituted product were detected in the crude reaction mixture by infrared spectroscopy, uncontaminated trans-substituted complexes were isolated after crystallization from dichloromethane/methanol. All complexes have been found to be sensitive to oxygen if in solution, with the rate of decomposition depending on the kind of ligand. However, if they are dry and under vacuum no apparent decomposition takes place. All synthesized complexes have been characterized by IR spectroscopy, 31P NMR, and by their melting points. The value of the presented synthesis is based on its high selectivity, extremely short reaction time, good to very good yields, and its simplicity

    Survival outcomes in a prospective randomized multicenter Phase III trial comparing patients undergoing anatomical segmentectomy versus standard lobectomy for non-small cell lung cancer up to 2 cm

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    OBJECTIVES The oncological equivalence of anatomical segmentectomy for early stage non-small cell lung cancer (NSCLC) is still controversial. Primary aim of this study was survival outcomes in combination with improved quality of life after segmentectomy compared with lobectomy in patients with pathological stage Ia NSCLC (up to 2 cm, 7th edition) MATERIALS AND METHODS: We conducted a prospective, randomized, multicenter phase III trial to confirm the non-inferiority of segmentectomy to lobectomy in regard to prognosis (trial No. DRKS00004897). Patients were randomized to undergo either segmentectomy or lobectomy and followed up for 5-years survival and tumor recurrence. The 5-year hazard ratio comparing lobectomy with segmentectomy was required to remain above 0.5. RESULTS Between October 2013 and June 2016, 108 patients with verified or suspected NSCLC up to 2 cm diameter were enrolled; 54 were assigned to lobectomy and 54 (1 drop-out) to segmentectomy. In-hospital and 90 days mortality was 0% in both groups. Overall survival at 5 years was 86.52% in the lobectomy compared to 78.21% in the segmentectomy group (HR = 0.61, (95% CI 0.23-1.66), p-value of non-inferiority test, p-ni = 0.687). Disease free survival was 77.29% for the lobectomy and 77.96% for the segmentectomy patients (HR = 1.50, (95% CI 0.60-3.76), p-ni = 0.019). At a median follow-up of 5 years, no differences were noted in either the locoregional or distant recurrent disease in both groups (9.4% vs 7.4%, p-ni = 0.506). CONCLUSION Overall survival, locoregional and distant recurrences was not significantly difference for patients undergoing either segmentectomy or lobectomy for stage Ia NSCLC. The targeted non-inferiority of segmentectomy to lobectomy could not be proven for primary endpoint overall survival, but was significant for the secondary endpoint of disease free survival

    Novel multiple sclerosis susceptibility loci implicated in epigenetic regulation.

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    We conducted a genome-wide association study (GWAS) on multiple sclerosis (MS) susceptibility in German cohorts with 4888 cases and 10,395 controls. In addition to associations within the major histocompatibility complex (MHC) region, 15 non-MHC loci reached genome-wide significance. Four of these loci are novel MS susceptibility loci. They map to the genes L3MBTL3, MAZ, ERG, and SHMT1. The lead variant at SHMT1 was replicated in an independent Sardinian cohort. Products of the genes L3MBTL3, MAZ, and ERG play important roles in immune cell regulation. SHMT1 encodes a serine hydroxymethyltransferase catalyzing the transfer of a carbon unit to the folate cycle. This reaction is required for regulation of methylation homeostasis, which is important for establishment and maintenance of epigenetic signatures. Our GWAS approach in a defined population with limited genetic substructure detected associations not found in larger, more heterogeneous cohorts, thus providing new clues regarding MS pathogenesis

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    A proteomic view of cell physiology of the industrial workhorse Bacillus licheniformis

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    Bacillus licheniformis is known for its high protein secretion capacity and is being applied extensively as a host for the industrial production of enzymes such as proteases and amylases. In its natural environment as well as in fermentation processes the bacterium is often facing adverse conditions such as oxidative or osmotic stress or starvation for nutrients. During the last years detailed proteome and transcriptome analyses have been performed to study the adaptation of B. licheniformis cells to various stresses (heat, ethanol, oxidative or salt stress) and starvation conditions (glucose, nitrogen or phosphate starvation). A common feature of the response to all tested conditions is the downregulation of many genes encodinghouse-keeping proteins and, consequently, a reduced synthesis of the corresponding proteins. Induction of the general stress response (sigma(B) regulon) is only observed in cells subjected to heat, ethanol or salt stress. This paper summarizes our current knowledge on general and specific stress and starvation responses of this important industrial bacterium. The importance of selected marker genes and proteins for the monitoring and optimization of B. licheniformis based fermentation processes is discussed. (C) 2014 Elsevier B.V. All rights reserved

    Cell Physiology and Protein Secretion of Bacillus licheniformis Compared to Bacillus subtilis

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    The genome sequence of Bacillus subtilis was published in 1997 and since then many other bacterial genomes have been sequenced, among them Bacillus licheniformis in 2004. B. subtilis and B. licheniformis are closely related and feature similar saprophytic lifestyles in the soil. Both species can secrete numerous proteins into the surrounding medium enabling them to use high-molecular-weight substances, which are abundant in soils, as nutrient sources. The availability of complete genome sequences allows for the prediction of the proteins containing signals for secretion into the extracellular milieu and also of the proteins which form the secretion machinery needed for protein translocation through the cytoplasmic membrane. To confirm the predicted subcellular localization of proteins, proteomics is the best choice. The extracellular proteomes of B. subtilis and B. licheniformis have been analyzed under different growth conditions allowing comparisons of the extracellular proteomes and conclusions regarding similarities and differences of the protein secretion mechanisms between the two species. Copyright (c) 2008 S. Karger AG, Base
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