ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Partial oxidation of methane to methyl chloride with tetrachloromethane on strontium hydroxyapatites ion-exchanged with lead (1997)
    Springer
    Catalysis letters 46 (1997), S. 279-285 
    Details
    ISSN: 1572-879X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partial oxidation of methane has been investigated in the presence and absence of tetrachloromethane (TCM) on strontium hydroxyapatites ion-exchanged with lead (SrPbHAp) at 773 K, at which temperature the apatites exist stably and do not convert to the corresponding phosphates. In the absence of TCM, the conversion of methane increased and the selectivity to carbon dioxide approached 100% as the lead content was increased. With a small quantity of TCM in the feedstream and at longer times-on-stream the selectivities to carbon dioxide decreased, those to carbon monoxide increased. Methyl chloride was formed at the higher times-on-stream on all catalyst compositions, but reached selectivities of 73% with those catalysts of Pb/Sr equal to or greater than 0.26. In contrast the conversion of methane decreased with increasing times-on-stream with the latter compositions. XRD and XPS measurements provide evidence for the introduction of Cl into the surface of PbSrAp, apparently forming the corresponding chlorapatite, although not precluding the existence of chlorine in additional configurations. Concomitantly a portion of the cationic lead is reduced to the metallic state. While TCM is evidently required for the production of methyl chloride, the presence of ion-exchanged lead appears to be required to achieve the highest selectivities for the aforementioned chloride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019039123113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Competitive oxidation of 1- and 2-propanol catalyzed by titanium silicalite-1 and the application for selective oxidation of 1-methoxy-2-propanol to 1-methoxy-2-propanone (1996)
    Springer
    Catalysis letters 36 (1996), S. 99-102 
    Details
    ISSN: 1572-879X
    Keywords: TS-1 ; competitive oxidation ; 1-and 2-propanol ; 1-methoxy-2-propanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Oxidation of 2-propanol with hydrogen peroxide catalyzed by TS-1 was strongly retarded in the presence of an equimolar 1-propanol to a level of 1-propanol oxidation, and the competitive oxidation behavior was applied for the selective oxidation of 1-methoxy-2-propanol to afford 1-methoxy-2-propanone in a high yield of 85%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807212
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Room-temperature formation of thermally stable aluminium-rich mesoporous MCM-41 (1998)
    Springer
    Catalysis letters 52 (1998), S. 21-23 
    Details
    ISSN: 1572-879X
    Keywords: RT synthesis ; thermal analysis ; NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The room-temperature (RT) synthesis of MCM-41 mesoporous compounds with high substitution levels of aluminium (Si / Al = 1.5) is achieved in a minimum time of synthesis. The compound shows similar characteristics to hydrothermally synthesized materials. 27Al NMR study confirms the presence of tetrahedral aluminium in as-synthesized material as well as in the calcined material without observing the presence of octahedral aluminium after calcination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019027605192
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Nucleotide sequences of two contiguous and highly homologous xylanase genes xynA and xynB and characterization of XynA from Clostridium thermocellum (1999)
    Springer
    Applied microbiology and biotechnology 51 (1999), S. 348-357 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A 5.7-kbp region of the Clostridium thermocellum F1 DNA was sequenced and found to contain two contiguous and highly homologous xylanase genes, xynA and xynB. The xynA gene encoding the xylanase XynA consists of 2049 bp and encodes a protein of 683 amino acids with a molecular mass of 74 511 Da, and the xynB gene encoding the xylanase XynB consists of 1371 bp and encodes a protein of 457 amino acids with a molecular mass of 49 883 Da. XynA is a modular enzyme composed of a typical N-terminal signal peptide and four domains in the following order: a family-11 xylanase domain, a family-VI cellulose-binding domain, a dockerin domain, and a NodB domain. XynB exhibited extremely high overall sequence homology with XynA (identity 96.9%), while lacking the NodB domain present in the latter. These facts suggested that the xynA and xynB genes originated from a common ancestral gene through gene duplication. XynA was purified from a recombinant Escherichia coli strain and characterized. The purified enzyme was highly active toward xylan; the specific activity on oat-spelt xylan was 689 units/mg protein. Immunological and zymogram analyses suggested that XynA and XynB are components of the C. thermocellum F1 cellulosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530051401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Immunohistochemical evidence that tumors elicit the synthesis of estrogen receptors in the submandibular gland of female rats (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 220-222 
    Details
    ISSN: 1420-9071
    Keywords: Estrogen ; receptor ; tumor ; submandibular gland ; 9,10-dimethyl-1,2-benzanthracene ; female rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have demonstrated the presence of estrogen receptor mRNA and the mature protein in the cytoplasm and nucleus, respectively, of a 9,10-dimethyl-1,2-benzathracene-induced submandibular gland tumor in female rats. We have previously shown that progesterone receptors are also present in human salivary gland tumors. These results suggest that endocrine therapy may be effective in treatment of submandibular gland tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01931100
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Superinduction of mouse epidermal ornithine decarboxylase activity by repeated 12-0-tetradecanoylphorbol-13-acetate treatments (1996)
    Springer
    Molecular and cellular biochemistry 155 (1996), S. 139-151 
    Details
    ISSN: 1573-4919
    Keywords: ODC ; PKC ; tumor promotion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A correlation of the levels of epidermal protein kinase C (PKC) isozymes, steady state levels of ornithine decarboxylase (ODC) mRNA, and ODC antizyme with the induction of ornithine decarboxylase (ODC) activity by a second repeat 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment to mouse skin was determined. A single application of TPA to female CD-1 mouse skin leads to a dramatic induction of ODC activity (≈3 nmol CO2/60 min/mg protein) which peaks at about 5 h after treatment. However, a superinduction of ODC activity (≈13 CO2/60 min/mg protein) is observed upon the second TPA application at 48 or 72 h after the first TPA treatment. Prior application of a tumor initiating dose of 7,12-dimethylbenz[a]anthracine to mouse skin did not influence the degree of induction of ODC by a repeat TPA treatment. Western Blot analyses using antibodies specific to PKC α, β, γ, ɛ and s indicate detectable levels of PKC α, β, δ and ε in mouse epidermal extracts. A time course of the effects of a single topical application of 20 nmol of TPA to the mouse skin indicate that none of PKC isozymes (α, β, γ, δ and ɛ) were completely downregulated at times (72 h) when ODC was overinduced by TPA. TPA-induced steady state levels of ODC mRNA did not correlate with the degree of superinduction of ODC activity by TPA. The second TPA treatment, 72 h after the first TPA treatment, which leads to superinduction of ODC activity did not decrease the levels of the ODC-antizyme. The results indicate that superinduction of mouse epidermal ODC activity is regulated in part post-transcriptionally and may not be the result of either a loss of PKC isoform(s) or a decrease in the levels of ODC antizyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229311
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    CPRF4a, a novel plant bZIP protein of the CPRF family: comparative analyses of light-dependent expression, post-transcriptional regulation, nuclear import and heterodimerisation (1998)
    Springer
    Molecular genetics and genomics 257 (1998), S. 595-605 
    Details
    ISSN: 1617-4623
    Keywords: Key words Chalcone synthase ; bZIP transcription factors ; Post-transcriptional regulation ; In vitro nuclear transport system ; UV light induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several DNA-binding proteins with conserved basic region/leucine zipper domains (bZIP) have been isolated from parsley. They all recognise defined ACGT-containing elements (ACEs), including ACE PcCHSII in the Light Regulatory Unit LRU1 of the CHS promoter which confers light responsiveness. A new member of this Common Plant Regulatory Factor (CPRF) family, designated CPRF4a, has been cloned, which displays sequence similarity to HBP-1a from wheat, as well as to other plant bZIP proteins. CPRF4a specifically binds as a homodimer to ACE PcCHSII and forms heterodimers with CPRF1 but not with CPRF2. In adult parsley plants, CPRF2 and CPRF4a mRNAs are found in all tissues and organs in which the chalcone synthase gene CHS is expressed. In protoplasts from suspension cultured cells, UV irradiation (290–350 nm) did not cause an increase in levels of CPRF1, CPRF2, or CPRF4a mRNA, whereas the corresponding CPRF proteins accumulated within 15 min of light treatment. Furthermore, the rapid light-mediated increase of CPRF proteins was insensitive to transcriptional inhibitors, suggesting that a post-transcriptional mechanism controls CPRF accumulation. CPRFs as well as Arabidopsisthaliana G-box binding factors (GBFs) are selectively transported from the cytosol into the nucleus, as shown in an in vitro nuclear transport system prepared from evacuolated parsley protoplasts, indicating that cytosolic compounds are involved in regulated nuclear targeting of plant bZIP factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A delay differential equation solver based on a continuous Runge–Kutta method with defect control (1997)
    Springer
    Numerical algorithms 16 (1997), S. 349-364 
    Details
    ISSN: 1572-9265
    Keywords: delay differential equations ; neutral equations ; continuous Runge–Kutta methods ; defect control ; 65L05 ; 65L06
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We have recently developed a generic approach for solving neutral delay differential equations based on the use of a continuous Runge–Kutta formula with defect control and investigated its convergence properties. In this paper, we describe a method, DDVERK, which implements this approach and justify the strategies and heuristics that have been adopted. In particular we show how the assumptions related to error control, stepsize control, and discontinuity detection (required for convergence) can be efficiently realized for a particular sixth-order numerical method. Summaries of extensive testing are also reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019107718128
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    5-Fluorouracil (5-FU) induced apoptosis in gastric cancer cell lines: role of the p53 gene (1997)
    Springer
    Apoptosis 2 (1997), S. 221-226 
    Details
    ISSN: 1573-675X
    Keywords: 5-FU ; apoptosis ; bax ; gastric cancer ; p53 ; p21/waf1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We examined chemosensitivity to 5-fluorouracil (5-FU) in four human gastric cancer cell lines, by analyzing the expression of p53 and its related genes. Treatment with 1mM 5-FU induced variable degrees of apoptosis in the cultured cells. The apoptotic indices 72 h after treatment were approximately 14% in MKN-74 (wild-type p53 gene), 12% in MKN-45 (wild-type), 3% in MKN-28 (mutated) and 0.5% in KATO-III cells (deleted), respectively. On the other hand, 50 μM 5-FU had little effect on the induction of apoptosis in MKN-74 cells, the value being approximately 2% after 72 h. Induction of P53 expression was noted 3 h after initiating the treatment, followed by the induction of P21/Waf1 after 6 h in both MKN-74 and MKN-45 cells. The same expression mode was noted in MKN-74 treated with 50 μM 5-FU. Conversely, the level of P53 expression was constant in MKN-28 cells and absent in KATO-III cells, in which P21/Waf1 had never been induced. The Bax/Bcl-2 expression ratio was gradually elevated for up to 72 h in MKN-74 and MKN-45 cells treated with 1mM 5-FU; in contrast, it was unchanged in MKN-28 and KATO-III cells, and MKN-74 treated with 50 μM 5-FU. These results might indicate that (1) 1mM 5-FU induces apoptosis in cultured gastric cancer cells carrying the wild-type p53 gene, but not those carrying the mutated type or a gene deletion, and (2) the elevated Bax/Bcl-2 expression ratio plays a more crucial role than the higher expression of P21/Waf1 in the induction of p53- gene dependent apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026476801463
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Anti-Fas antibody-induced apoptosis in human colorectal carcinoma cell lines: role of the p53 gene (1998)
    Springer
    Apoptosis 3 (1998), S. 431-437 
    Details
    ISSN: 1573-675X
    Keywords: Apoptosis ; Colorectal Carcinoma ; FAS ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The cell surface Fas antigen transducts an apoptotic signal by its crosslinking with Fas ligand or anti-Fas antibody in a variety of human cultured cells. In this study, we examined the expression of Fas antigen and its mediation of apoptosis in six human colorectal carcinoma cell lines. A flow cytometric analysis revealed that LoVo, DLD-1, WiDr and SW837 cell lines showed higher expression levels of Fas antigen, in contrast to lower expression in COLO201 and COLO320DM. Interferon-γ enhanced the expression of Fas antigen in all of the cell lines examined. Both Fas ligand and Fas-associated phosphatase-1 (FAP-1) were expressed only in COLO320DM. Anti-Fas antibody induced apoptosis in LoVo carrying wild-type p53 gene, but not in the other five cell lines carrying mutated p53 gene. The transfection of wild-type p53 gene using an adenovirous vector upregulated P53 protein in WiDr and SW837 cells, both of which showed, however, no increase in apoptotic cells by anti-Fas antibody treatment. These results indicated that (1) Fas antigen was variably expressed, regardless of the p53 gene status and (2) the susceptibility to anti-Fas antibody-mediated apoptosis did not correlate to Fas, Fas ligand or FAP-1 expression levels. Therefore, we conclude that wild-type P53 expression might not necessarily be essential for Fas-mediated apoptosis in human colorectal carcinoma cell lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009662619907
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...