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Central German lignites with high numbers of aliphatic and bituminous molecular structures are potential feedstocks for light hydrocarbons as intermediates for the chemical industry. This study pursues a new approach to the direct conversion of lignites by heterogeneous catalysis under pyrolytic conditions and without additional hydrogenation. Promising results were achieved in lab-scale investigations with ZSM-5 catalyst and these results were confirmed at a semi-technical scale rotary kiln. ZSM-5-coated beads were examined as an interesting alternative for reutilization and simple separation from the solid pyrolysis products. Based on parameter studies, the maximum yields of low molecular hydrocarbons occurred at a reaction temperature of 500 °C at a catalyst-to-coal ratio of 0.1 to 0.2 (maf). Comparison between the pulverized one-way ZSM-5 catalyst and ZSM-5-coated beads shows similar results concerning the amounts of pyrolysis products, especially gaseous alkenes like propene. At a certain catalyst-to-coal ratio, comparable results of propene liberation can be found also. The main reaction pathways were identified based on the distribution of the catalytic pyrolysis products, especially of low molecular hydrocarbons. [ABSTRACT FROM AUTHOR]

Nonintegrating gene delivery vectors have an improved safety profile compared with integrating vectors, but transgene retention is problematic as nonreplicating episomes are progressively and rapidly diluted out through cell division. We have developed an integration-deficient lentiviral vector (IDLV) system generating mitotically stable episomes capable of long-term transgene expression. We found that a transient cell cycle arrest at the time of transduction with IDLVs resulted in 13-45% of Chinese hamster ovary (CHO) cells expressing the transgene for over 100 cell generations in the absence of selection. The use of a scaffold/matrix attachment region did not result in improved episomal retention in this system, and episomes did not form after transduction with adeno-associated viral or minicircle vectors under the same conditions. Investigations into the episomal status of the vector genome using (1) linear amplification-mediated polymerase chain reaction followed by deep sequencing of vector-genome junctions, (2) Southern blotting, and (3) fluorescent in situ hybridization strongly suggest that the vector is not integrated in the vast majority of cells. In conclusion, we have developed an IDLV procedure generating mitotically stable episomes capable of long-term transgene expression. The application of this approach to stem cell populations could significantly improve the safety profile of a range of stem and progenitor cell gene therapies. [ABSTRACT FROM AUTHOR]

Several events of insertional mutagenesis in pre-clinical and clinical gene therapy studies have created intense interest in assessing the genomic insertion profiles of gene therapy vectors. For the construction of such profiles, vector-flanking sequences detected by inverse PCR, linear amplification-mediated-PCR or ligation-mediated-PCR need to be mapped to the host cell's genome and compared to a reference set. Although remarkable progress has been achieved in mapping gene therapy vector insertion sites, public reference sets are lacking, as are the possibilities to quickly detect non-random patterns in experimental data. We developed a tool termed QuickMap, which uniformly maps and analyzes human and murine vector-flanking sequences within seconds (available at www.gtsg.org). Besides information about hits in chromosomes and fragile sites, QuickMap automatically determines insertion frequencies in +/− 250 kb adjacency to genes, cancer genes, pseudogenes, transcription factor and (post-transcriptional) miRNA binding sites, CpG islands and repetitive elements (short interspersed nuclear elements (SINE), long interspersed nuclear elements (LINE), Type II elements and LTR elements). Additionally, all experimental frequencies are compared with the data obtained from a reference set, containing 1 000 000 random integrations (‘random set’). Thus, for the first time a tool allowing high-throughput profiling of gene therapy vector insertion sites is available. It provides a basis for large-scale insertion site analyses, which is now urgently needed to discover novel gene therapy vectors with ‘safe’ insertion profiles.Gene Therapy (2009) 16, 885–893; doi:10.1038/gt.2009.37; published online 23 April 2009 [ABSTRACT FROM AUTHOR]

This review addresses the research done regarding ammoxidation of lignins and other lignocellulosic materials, as a way to produce nitrogen-rich products. The reported methods of ammoxidation of technical lignins are summarized giving emphasis to the diverse nitrogen structures which may yield and their effect on nitrogen release. The process using ammonia (NH 3) under oxygen (O 2) atmosphere is the best way to produce nitrogen-rich products. Nitrogen is first incorporated as ammonia in carbonyl and carboxyl groups which then lead to aromatic ring cleavages and formation of amides. The reactions then proceed to form heterocyclic compounds with bound nitrogen. The studies show that most of the nitrogen is incorporated as strongly-bound nitrogen which results in products with long-term release properties. This can cause problems of nitrogen availability in the first growth periods of cultivation tests and lead to higher loads of fertilizers needed to have good performances, which constitutes a disadvantage for its use in horticultural substrates that require mid-term nitrogen availability. This article compiles the main challenges arising from studies carried out in recent years, particularly for the development of nitrogen-rich lignins and wood fibres with nitrogen structures that constitute an effective solution to the problem of nitrogen immobilization. This could enable the development of substrate improvers that are an effective substitute for peat in horticultural substrates, allowing cleaner production by using renewable materials and by-products such as lignin while reducing the use of a non-renewable, greenhouse-gases-emitting material. [Display omitted] • Lignin ammoxidation may be crucial for peat substitution with wood fibers • Few studies link lignin's nitrogen groups to nutrient availability in plant tests. • Current methods to evaluate nitrogen structures in lignin are time-consuming • Amide-type nitrogen provides mid-term availability to counter nitrogen immobilization • Further studies are needed to optimize ammoxidation for mid-term available nitrogen [ABSTRACT FROM AUTHOR]

In order to enhance the usability of beech wood slow pyrolysis liquid, an optimization of the extraction process with supercritical carbon dioxide (scCO 2) has been carried out. The main goals were to minimize losses and to stabilize the extraction parameters. Different designs of extraction vessels were used to accelerate the extraction and to facilitate the extraction of slow pyrolysis liquids on silica gel as well as in its liquid state. The slow pyrolysis liquid was extracted at different scCO 2 densities and temperatures. The densities were approx. 355 and 725 kg/m3 at 313.15 and 333.15 K respectively. A high density is the primary factor in increasing the extraction yield. An elevated temperature at high density level further increased the yields. The distribution of GC-MS detectable compounds of the extracts changed distinctly, resulting in an increase of syringols and a decrease of acids, ketones and furans during extraction. [Display omitted] • Optimization of scCO 2 extraction process to enable stable process parameters. • Optimization of the separation system to minimize losses. • Usability raise of slow pyrolysis liquid, a charcoal by-product. • Slow Pyrolysis liquid is rich in guaiacols, syringols, ketones, esters and acids. • Use of different scCO 2 densities and investigation on the extract composition. [ABSTRACT FROM AUTHOR]

In this work the advantages of direct conversion of lignite with zeolite catalysts under inert conditions are shown. The main desired products were low chain hydrocarbons with high added value like olefins and aromatics. The yield of the desired products depends on the used lignite catalyst system. One main factor is the hydrogen content of the lignite and the amount of volatile matter, respectively. For one system yields of 12% propene and butenes were observed. Another main factor is the temperature of the process. Optimal conditions were found at about 500 °C with one specified system. To reduce the tar yield, a high catalyst to lignite ration seems to be suitable. It was considered that this is due to enhanced contact time between the lignite and the catalyst as well as the contact time between tar and the catalyst. Based on additional differential thermal analysis (DTA) fractional coupled with ir and tar analysis a model was proposed for the reaction system. [ABSTRACT FROM AUTHOR]

Graft-versus-host disease (GvHD) is a severe complication in the context of allogeneic stem cell transplantation and adoptive immunotherapy. The transfer of a suicide gene into donor T-lymphocytes (TLCs) allows selective elimination of GvHD-causing cells. As retroviral gene transfer into hematopoietic stem cells can induce leukaemia, there is an urgent need also to analyze retroviral integration sites in TLCs. We examined suicide gene-transduced TLCs in four grafts and from four transplanted patients. One-hundred and fifteen integration sites were detected in vitro. Of these 90 could be mapped to the human genome; 50% (45) were located in genes and 32% (29) were detected 10 kb upstream or downstream of transcription start sites. We found a significant overrepresentation of genes encoding for proteins with receptor activity, signal transducer activity, transcription regulator activity, nucleic acid binding activity and translation regulator activity. Similar data were obtained from patient samples. Our results point to preferred vector integration patterns, which are specific for the target cell population and probably independent of selection processes. Thus, future preclinical analysis of the integration repertoire with abundant amounts of transduced cells could allow a prediction also for the in vivo situation, where target cells are scarce.Bone Marrow Transplantation (2006) 38, 229–235. doi:10.1038/sj.bmt.1705424; published online 19 June 2006 [ABSTRACT FROM AUTHOR]