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
Filter
  • Articles  (31)
  • Cell & Developmental Biology  (20)
  • Polymer and Materials Science  (11)
  • Biology  (20)
  • Physics  (11)
  • 1
    Electronic Resource
    Electronic Resource
    Partial swelling of latex particles with monomers (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 2049-2063 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two methods are described for experimentally determining the concentrations of monomer in both the aqueous phase and the latex particle phase during partial swelling of latex particles, and therefore also during intervall III of an emulsion polymerization. The ratio of the monomer concentrations in the aqueous phase, both below and at saturation, can be related to the volume fraction of polymer in the latex particles via the Vanzo equation. Comparison of theory and experiments for the methyl acrylate and poly(methyl acrylate-co-styrene) system shows that the monomer partitioning is insensitive to temperature, latex particle radius, polymer composition, polymer molecular weight and polymer cross-linking. Thermodynamic treatment of these and previously published partitioning results shows, at higher volume fractions of polymer, that the conformational entropy of mixing of monomer and polymer is the significant term determining the degree of partial latex particle swelling by monomer. Theoretical predictions of experimental results are quite insensitive to values of the Flory-Huggins interaction parameter and to the latex particle-water interfacial tension. A simple model is developed for the estimation of monomer partitioning which requires only the saturation monomer concentrations in the particle and aqueous phases.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930823
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The effect of chain transfer agent on the entry of free radicals in emulsion polymerization (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 303-313 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The model of Maxwell et al. (Macromolecules 24, 1629 (1991)) for initiator efficiencies in emulsion polymerization has been extended to take into account the effect of added chain transfer agent (CTA). The model supposes that the rate-determining step for radical entry into latex particles is aqueous-phase propagation of the primary free radicals to a critical chain length z required for entry (forming species such as .MzSO-4, where M is a monomer entity and peroxodisulfate S2O2-8 is the initiator). The effect of CTA on the entry rate is assumed to occur by facilitating the production of aqueous-phase free-radical species (CTA.) by transfer between species such as .MzSO-4 (where n 〈 z) and CTA in the aqueous phase. The CTA. will be formed at a reasonable rate provided the CTA is not too water-insoluble (e.g. C12H25SH); it should also be capable of entering the latex particles rapidly because of its relative insolubility. If the monomer-derived .MnSO-4 tend to suffer aqueous-phase termination rather than entry, the overall rate of entry (and hence initiator efficiency) will be increased. This can explain the accelerating effect of intermediate molecular weight CTA's on emulsion polymerization of monomers such as butadiene, where z is large and hence initiator efficiency is very low in the absence of CTA, because most .MnSO-4 undergo termination rather than entry into the latex particles.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Diffusion of dissolved gases in molten condensation polymers (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2587-2589 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111218
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Flow-induced structure and rheology of a triblock copolymer (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 1585-1600 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Linear viscoelastic properties are found to be a sensitive measure of flow-induced structural changes in a block copolymer. Styrene-butadiene-styrene block copolymer (SBS) with 26% polystyrene (PS) forms a macrostructure in the quiescent state with grains of the order of 1-10 μm. Within each grain, phase separation gives rise to a regular two-phase microstructure with cylindrical PS domains with radius of the order of 200 Å. Large-amplitude oscillatory shear (γ = 4.5) at temperatures between 139 and 181°C was applied to after the grain structure with the objectives of removing the discontinuities at the grain boundaries and of aligning the domains into a continuous ultrastructure. The SBS behaved like a solid (tan δ 〈 1 at low ω) before and like a liquid (tan δ 〉 1) after shear modification. This change expressed itself in the removal of the long relaxation times from the linear viscoelastic spectrum; the intermediate and low relaxation times were not affected by the shear modification. The viscoelastic spectrum slowly recovered during annealing with recovery times of the order of the longest relaxation time of the quiescent structure. Birefringence studies showed that the SBS did not recover into its original grain structure but into a highly oriented domain structure. The discontinuities at the grain boundaries could not be removed completely.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330514
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effects of thymosin β4 and thymosin β10 on actin structures in living cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 13-25 
    Details
    ISSN: 0886-1544
    Keywords: Tβ4 ; Tβ10 ; β-thymosins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The β-thymosins are a family of small proteins originally isolated from the thymus. Recently, two of the major mammalian isoforms, thymosin β4 (Tβ4) and thymosin β10 (Tβ10), are identified as significant actin monomer sequestering proteins which may be involved in regulating actin filament assembly. To study the cellular function of β-thymosins, we have used isoform-specific antibodies to determine their concentration and intracellular distribution, and examined the effects of inducing overexpression of Tβ4 and Tβ10 on actin filament structures. Immunofluorescence labeling of peritoneal macrophages showed that both β-thymosins are uniformly distributed within the cytoplasm. cDNA-mediated overexpression of β-thymosins in CV1 fibroblasts induced extensive loss of phalloidinstained actin stress fibers. Stress fibers in the cell center were more susceptible than those at the periphery. There was a decrease in the number of focal adhesions, as evidenced by a decrease in discrete vinculin staining and an increase in diffuse vinculin fluorescence. The majority of the transfected cells had normal shape in spite of extensive loss of actin filaments. Occasionally, cells overexpressing β-thymosin were observed to divide. In these cells, β-thymosin was excluded from the midbody which contains an actin filament-rich contractile ring. Our results indicate that Tβ4 and Tβ10 are functionally very similar and both are effective regulators of a large subset of actin filaments in living cells. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Vitamin D receptor alleles and bone physiology (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 56 (1994), S. 307-314 
    Details
    ISSN: 0730-2312
    Keywords: vitamin D calcitriol ; bone ; genetics ; steroid hormone receptor ; vitamin D receptor ; retinoic acid receptor ; calcium ; homeostasis ; calcitonin ; parathyroid hormone ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The vitamin D endocrine system is central to the control of bone and calcium homeostasis. The active hormonal aform of vitamin D, 1,25 dihydroxyvitamin D (calcitriol), the circulating level of which is tightly regulated, acts through a specific receptor to mediate its genomic actions on almost every aspect of calcium homeostasis. Because of its transactivation function, it possible that a small difference in vitamin D receptor level could be amplified into a biologically significant alteration in physiological setpoint. The recent finding that polymorphisms in the vitamin D receptor gene are predictive of bone density (morrison et al., Nature 367:284-287, 1994) is the first example of an allelic effect in such a homeostatically controlled system. This raises the possibility that such central operators may exist in other regulatory pathways, and could expllain a large part of the observed “ormal” population distribution that exists for all physiological paraameters.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240560306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    PTH-responsive osteoblast nuclear matrix architectural transcription factor binds to the rat type I collagen promoterThe first two authors contributed equally to this work. (1998)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 69 (1998), S. 336-352 
    Details
    ISSN: 0730-2312
    Keywords: architectural transcription factor ; nuclear matrix ; osteoblast ; parathyroid hormone ; type I collagen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In connective tissue, cell structure contributes to type I collagen expression. Differences in osteoblast microarchitecture may account for the two distinct cis elements regulating basal expression, in vivo and in vitro, of the rat type I collagen α1(I) polypeptide chain (COL1A1). The COL1A1 promoter conformation may be the penultimate culmination of osteoblast structure. Architectural transcription factors bind to the minor groove of AT-rich DNA and bend it, altering interactions between other trans-acting proteins. Similarly, nuclear matrix (NM) proteins bind to the minor groove of AT-rich matrix-attachment regions, regulating transcription by altering DNA structure. We propose that osteoblast NM architectural transcription factors link cell structure to promoter geometry and COL1A1 transcription. Our objective was to identify potential osteoblast NM architectural transcription factors near the in vitro and in vivo regulatory regions of the rat COL1A1 promoter. Nuclear protein-promoter interactions were analyzed by gel shift analysis and related techniques. NM extracts were derived from rat osteosarcoma cells and from rat bone. The NM protein, NMP4, and a soluble nuclear protein, NP, both bound to two homologous poly(dT) elements within the COL1A1 in vitro regulatory region and proximal to the in vivo regulatory element. These proteins bound within the minor groove and bent the DNA. Parathyroid hormone increased NP/NMP4 binding to both poly(dT) elements and decreased COL1A1 mRNA in the osteosarcoma cells. NP/NMP4-COL1A1 promoter interactions may represent a molecular pathway by which osteoblast structure is coupled to COL1A1 expression. J. Cell. Biochem. 69:336-352. © 1998 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Identification of a vitamin D3 response element in the fibronectin gene that is bound by a vitamin D3 receptor homodimer (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 322-333 
    Details
    ISSN: 0730-2312
    Keywords: fibronectin ; VDR ; homodimer ; vitamin D regulation ; transcription ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Fibronectin (FN) is an important adhesive noncollagenous glycoprotein involved in maintenance of the extracellular matrix and cell adhesiveness, loss of which has been implicated in the metastatic potential of cells. Regulation of FN occurs at the transcriptional level by the active metabolite of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). Transient transfection of homologous and heterologous promoter reporter constructs into ROS 17/2,8 (rat osteosarcoma), NIH 3T3 (mouse fibroblast), and MCF-7 (human mammary carcinoma) cell lines showed a consistent two- to threefold induction of transcription when stimulated with 1,25-(OH)2D3. These heterologous promoter transfection studies with gel shift analysis locate a third, natural DR6-type vitamin D responsive element (VDRE) at nucleotide positions -171 to -154 in the murine FN promoter. Interestingly, this VDRE is also present in rat and human FN promoters. This study shows that 1,25-(OH)2D3 induces FN transcription from an existing elevated basal transcriptional activity by acting through two putative hexameric core binding motifs which bind VDR homodimers. Furthermore, the FN VDRE is the first homodimer-type VDRE that is not overlaid by a DR3-type structure. © 1996 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    G/C element contributes to the cell line-specific expression of the proximal osteocalcin promoter (1995)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 58 (1995), S. 499-508 
    Details
    ISSN: 0730-2312
    Keywords: osteocalcin promoter ; G/C element ; collagen type I (α1) promoter ; osteoblast ; ORE-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Sequential activation of cell type-specific genes occurs during osteoblast development. The promoter of one such gene, osteocalcin, has been widely studied, but the DNA sequences that govern osteoblast-specific expression have not been defined. The proximal osteocalcin promoter linked to pTKCAT directs strong promoter activity in osteoblast-like ROS17/2.8 cells and comparatively weak promoter activity in nonosteoblastic NIH3T3 cells. To identify sequences important in conferring cell-specific expression of the osteocalcin gene, a deletion series of the human proximal promoter was constructed and the activities assessed in ROS17/2.8 and NIH3T3 cells. These studies identified a 30 bp sequence within the proximal promoter (osteocalcin repressor element-1 [ORE-1]) which is responsible for repressing the transcriptional activity in NIH3T3 cells. In electrophoretic mobility shift assays from both NIH3T3 and ROS17/2.8 cells, a protein complex bound to the ORE-1 that was related to a complex which binds the G/C-rich repressor element in the collagen type I (α1) promoter. In addition, there was a second complex from NIH3T3 cells but not ROS17/2.8 cells that bound the ORE-1 fragment. The presence of this additional factor in NIH3T3 cells parallels the observation that constructs carrying the ORE-1 sequence have repressed promoter activity relative to the analogous constructs lacking the ORE-1 when transfected into NIH3T3 and suggests that the NIH3T3-specific factor is a repressor. These data indicate that the G/C element in the ORE-1 contributes to the repression of osteocalcin gene transcription in a nonosteoblast cell line. The high homology between the ORE-1 sequence and a related sequence and a related sequence in the collagen type I (α2) proximal promoter suggests that homologous regions in other osteoblast-expressed genes may function similarly.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240580413
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    rHox: A homeobox gene expressed in osteoblastic cells (1995)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 59 (1995), S. 486-497 
    Details
    ISSN: 0730-2312
    Keywords: homeobox gene ; rHox ; rat ; osteocalcin ; collagen I α 1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Homeodomain proteins are characterized by a conserved domain with a helix-turn-helix motif. These proteins act as regulatory factors in tissue differentiation and proliferation. However, their role in the regulation of osteoblast differentiation is unknown. In this study we have identified and characterized a homeobox gene in osteoblast-like cells. This gene, termed rHox, was isolated from a cDNA library derived from rat osteoblast-like cells. The nucleotide sequence of the 1,375 base pair (bp) cDNA contains a noncoding leader sequence of 329 bp, a 735 bp open reading frame, and 312 bp of 3′ noncoding sequence. Sequence comparison demonstrates that rHox is identical to the mouse Pmx gene (also called MHox) at the amino acid level and 90% homologous at the nucleotide level. Both Southwestern blotting and gel shift analyses indicate that rHox has potential to bind both the collagen l α 1 and the osteocalcin promoters. Transfection experiments using an rHox expression vector showed a strong repression of target promoter activity, regardless of whether the target promoters contained homeodomain binding reponse elements. These data suggest that rHox is a potent negative regulator of gene expression, although the specific role of rHox in bone gene regulation remains to be determined. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240590409
    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...