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  • Articles  (5,556)
  • Polymer and Materials Science  (5,493)
  • Bone  (63)
  • Cell & Developmental Biology
  • General Chemistry
  • 1975-1979  (5,556)
  • Physics  (5,556)
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  • Articles  (5,556)
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  • 1
    Electronic Resource
    Electronic Resource
    Radioautographic visualization of3H-fucose incorporation into glycoprotein by osteoblasts and its deposition into bone matrix (1979)
    Springer
    Calcified tissue international 27 (1979), S. 177-185 
    Details
    ISSN: 1432-0827
    Keywords: Calcification ; Bone ; Glycoprotein ; Golgi ; Osteoblasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The elaboration of bone matrix glycoprotein by osteoblasts of alveolar bone was investigated by radioautography after the intravenous injection of3H-fucose into young rats. At selected times after injection, animals were sacrificed by intracardiac perfusion and demineralized specimens were prepared for light and electron microscope radioautography. At 5 and 10 min after injection, when the blood fucose level was high, silver grains were restricted to the spheroidal and cylindrical saccules of the Golgi apparatus. At 20 min membrane-limited secretory granules were also labeled. By 35 min, the blood fucose level had dropped and silver grains were detected over the apical cortical cytoplasm, in association with secretory granules located therein. Some grains were present over osteoblast processes and the adjacent prebone matrix. By 4 h most of the silver grains had left the cell. At that time they were observed over prebone, adjacent to osteoblast processes, as well as over the prebone-bone junction where a distinct band of label was noted. In demineralized preparations an electron-dense granular material was present at the prebone-bone junction in association with collagen fibrils. These findings provide evidence that osteoblasts in alveolar bone synthesize fucose-containing glycoprotein and indicate that the addition of3H-fucose occurs in the Golgi apparatus. The glycoprotein passes to the apical cortical cytoplasm by way of membrane-limited secretory granules, is exteriorized, and accumulates at the site where prebone transforms into bone (the prebone-bone junction). Since this is also the site of the calcification front, the deposition of labeled glycoprotein may be related to the deposition of bone mineral.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441182
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  • 2
    Electronic Resource
    Electronic Resource
    Bone fluoride concentrations associated with fluoridated drinking water (1979)
    Springer
    Calcified tissue international 27 (1979), S. 95-99 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Fluoride ; Analysis ; Food ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Recently published bone fluoride values from Iowa are very high compared to earlier reports, suggesting an increase in fluoride intake. Reanalysis of the Iowa specimens shows levels one-fourth those reported by the Iowa laboratory indicating an error in the original report. Seventeen bone specimens, collected from long-term residents of Rochester, New York, drinking 1 ppm F− water, had a mean value of 2085±270 ppm F− on an ashed-weight basis. This value is not significantly different from that predicted by the data of Zipkin et al. in 1958. These data, therefore, do not support the contention that there has been an increase in fluoride intake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441168
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  • 3
    Electronic Resource
    Electronic Resource
    Use of a spectrophotometer for radiographic photodensitometry of bone (1979)
    Springer
    Calcified tissue international 28 (1979), S. 103-105 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Photodensitometry, X-ray ; Radiography ; Spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A conventional spectrophotometer was used to do radiographic photodensitometry of bone mass. An experiment to produce osteoporosis in guinea pigs required quantification of changes in bone mass. Lack of a densitometer necessitated finding another method for quantification. The method developed involved using industrial film in a closed X-ray system. Optical density of X-rays was then read in a spectrophotometer at nine femur locations. Highly significant correlations between optical density and femur calcium content and femur dry weight per millimeter were obtained. Histological sections from an animal with low optical density measurements confirmed bone loss by showing decreased cortical width and loss of trabecular bone. In addition to using readily available equipment, this method offers the advantage of being able to detect bone loss in specific areas of the bones. In addition, bones are left intact and can be used for other purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441227
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  • 4
    Electronic Resource
    Electronic Resource
    Analysis of paramagnetic centers in X-ray-irradiated enamel, bone, and carbonate-containing hydroxyapatite by electron spin resonance spectroscopy (1979)
    Springer
    Calcified tissue international 28 (1979), S. 107-112 
    Details
    ISSN: 1432-0827
    Keywords: ESR ; Bone ; Enamel ; CO3-Apatite ; Paramagnetism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Carbonate-containing hydroxyapatite, enamel, and bone were irradiated by an X-ray and investigated between 77° and 350°K by means of electron spin resonance (ESR) spectroscopy. The ESR spectrum of enamel irradiated at 77°K in vacuum and observed at the same temperature was almost the same as that of the carbonate-containing hydroxyapatite. The temperature dependence of signal intensities confirms a spin-energy exchange between the mineral and organic constituents in bone, but in enamel no or very little spinenergy exchange between the mineral and organic constituents. Considerable similarity among the ESR spectra of enamel, bone, and carbonate-containing apatite was obtained after X-ray irradiation in air at 300°K with both an X-band and a Q-band ESR spectrometer. The Q-band spectrum can be interpreted in terms of two paramagnetic species. One is identified as a CO 3 3− anion radical which has an axial symmetry withg factors of 2.0029 and 1.9972. The other species is found to be centered atg=2.0019.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441228
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  • 5
    Electronic Resource
    Electronic Resource
    On the solid state of bone (1979)
    Springer
    Calcified tissue international 28 (1979), S. 33-36 
    Details
    ISSN: 1432-0827
    Keywords: Infrared, visible light ; Bone ; Collagen ; Apatite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Photovoltaic effect (infrared and visible light) is observed in bone and its two major components, collagen and apatite, at room temperature. A dimunition in the magnitude of photovoltage is observed after exposure to ultraviolet light in all the cases. The drift mobility of the charge carriers is obtained by measuring I versus V relationships in sandwich samples and relating them to the permitivity of the medium. Lifetime of the injected carriers is measured in the usual way. The data are consistent with the hypothesis that the effects are due to protonic conduction phenomena.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441215
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  • 6
    Electronic Resource
    Electronic Resource
    Growth of embryonic chick tibiae in ovo and in vitro: A scanning electron microscope study (1979)
    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    Details
    ISSN: 1432-0827
    Keywords: Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441158
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  • 7
    Electronic Resource
    Electronic Resource
    An ultrastructural study of the role of calcification nodules in the mineralization of woven bone (1979)
    Springer
    Calcified tissue international 27 (1979), S. 57-64 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Bone formation ; Calcification ; Calcification nodule ; EM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Osteolathyrism has been used as an experimental model for the study of calcification nodules during the mineralization process. Periosteal exostoses developing in osteolathyrism characteristically have spherical basophilic structures (calcification nodules) in the vicinity of developing bone spicules. In thin sections, the nodules were seen scattered between collagen fibers in the intercellular matrix. Collagen fibers did not appear to be present within the nodules but sometimes were packed just outside them. Matrix vesicles were also present in areas of early mineralization. After EDTA decalcification, the majority of the nodules consisted of a fine granular material surrounded by an electron-dense peripheral zone. The peripheral dense zone was occasionally incomplete in small nodules in areas of early mineralization. An electron-dense central area could be observed in the center of the nodules. Evidence has been presented indicating that the calcification nodules arise from smaller mineralization foci, presumably matrix vesicles. The calcification nodules enlarge to approximately 1.0 µm in size, at which point development is slowed or halted allowing the formation of the peripheral dense zone. Although coalescence of nodules was observed, this was more a random event. The further mineralization of the trabeculae was achieved by the calcification of the collagen fibers. The mineralized trabeculae reflected this pattern of nodular and collagenous calcification. It is suggested that this pattern of calcification is characteristic of rapidly developing woven bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441162
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  • 8
    Electronic Resource
    Electronic Resource
    Age-related changes in the density and tensile strength of human femoral cortical bone (1979)
    Springer
    Calcified tissue international 27 (1979), S. 105-108 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Femur ; Strength ; Density ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In order to ascertain whether the intrinsic strength of human bone changes with age or not, we have determined the ultimate tensile strength and density of strips of femoral cortical bone. These femora were collected from cadavers varying in age from 13 to 97 years. The results show that both density and intrinsic strength of bone increase up to about the fourth decade of life and then decrease with age. However, the rate of decrease of strength is greater than that of density. This indicates that the density of bone is not the sole determining factor of its strength, and that some other factors play an important part.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441170
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  • 9
    Electronic Resource
    Electronic Resource
    Distribution of the perilacunar hypomineralized areas in cortical bone from patients with familial hypophosphatemic (vitamin D-resistant) rickets (1979)
    Springer
    Calcified tissue international 27 (1979), S. 101-104 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Rickets ; Hypophosphatemia ; Microradiography ; D-resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The perilacunar areas of low mineral density in microradiographs from cortical bone of patients with hypophosphatemic (vitamin D-resistant) rickets are not evenly distributed throughout the bone tissue. Their frequency and distribution were determined in bone from 9 patients with this disease. It was found that the lesion was more frequent in haversian bone than in interstitial bone, and along the inner circumference of growing haversian systems as compared with the outer circumference. These findings indicate that the lesion is the result of retarded mineralization, and that mineralization slowly proceeds in these areas as the bone becomes older. A relatively high frequency of the lesion was also found in osteons with an elliptical cross section along the long axis of the ellipse. The cause of the abundance of the lesion at these sites is not clear, but it is possible to explain the uneven distribution in elliptical osteons by assuming an unequal rate of bone formation in these structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441169
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of carbon dioxide and various oxygen tensions on the respiratory activity of bone (1979)
    Springer
    Calcified tissue international 27 (1979), S. 165-169 
    Details
    ISSN: 1432-0827
    Keywords: Oxygen uptake ; Bone ; Oxygen tension ; Carbon dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present study was carried out to determine the influence of carbon dioxide and oxygen tension on the respiratory activity of bone cells in mouse calvaria in vitro. Five-day-old mouse calvaria were removed aseptically and incubated individually for 1 h at 37° C in a closed reaction chamber containing 1.5 ml of tissue culture medium made up of 60% horse serum in Gey's solution containing 100 unit/ml penicillin and 100µg/ml streptomycin. Before the calvaria were added, the medium in the incubation chamber was equilibrated with 10%, 20%, 30%, or 50% oxygen balanced with nitrogen. The effect of CO2 on oxygen utilization by the calvaria was determined by incubating the calvaria in a medium previously equilibrated with either 50% O2 balanced with N2 or 50% O2 and 5% CO2 balanced with N2. At each oxygen tension, the rate of oxygen utilization by the calvaria was measured polarographically by a Clark oxygen electrode. The results showed that the rate of oxygen uptake of bone increased as the oxygen tension increased and carbon dioxide stimulated significantly the rate of oxygen utilization by the bone cells. In view of the previous reports that both carbon dioxide and oxygen tension are implicated in the process of bone resorption, it is suggested that these two factors may affect bone resorption by influencing the oxygen utilization by bone cells and ultimately controlling their energy metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441180
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  • 11
    Electronic Resource
    Electronic Resource
    X-ray diffraction of the calcified tissues inPolypterus (1979)
    Springer
    Calcified tissue international 28 (1979), S. 37-42 
    Details
    ISSN: 1432-0827
    Keywords: X-ray diffraction ; Hydroxyapatite ; Whitlockite ; Fish (Pisces) ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Pyrolyzed scales, fin spines, and bone from the ray-finned bony fishPolypterus (Actinopterygii) showed two mineral phases on X-ray diffraction: hydroxyapatite (HA), Ca5(PO4)3OH, and whitlockite, Ca3(PO4)2. The ratio of HA/whitlockite varied with the structure (scale, spine, bone) within each individual fish. The relative proportions of HA to whitlockite in pyrolyzed samples reflected the Ca/P ratio of the sample. Whitlockite appears after pyrolysis when the Ca/P is lower than 1.67. Among the five fish investigated, for each structure a general trend was noted. The proportion of HA relative to whitlockite increased with size (age) of the fish. Thus the smallest fish, a juvenile, exhibited a low Ca/P mineral in its calcified tissues, whereas the larger fish had progressively more HA and less whitlockite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441216
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  • 12
    Electronic Resource
    Electronic Resource
    Disordered mineral metabolism produced by ketogenic diet therapy (1979)
    Springer
    Calcified tissue international 28 (1979), S. 17-22 
    Details
    ISSN: 1432-0827
    Keywords: Anticonvulsant ; Ketogenic diet ; Calcium ; Vitamin D ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Vitamin D and mineral metabolism status was examined in five children maintained chronically on combined ketogenic diet-anticonvulsant drug therapy (KG), and the results compared to those obtained in 18 patients treated with anticonvulsant drugs alone (AD) and 15 normal controls. KG patients exhibited biochemical findings of vitamin D deficiency osteomalacia: decreased serum 25-hydroxyvitamin D (25OHD) and calcium concentrations, elevated serum alkaline phosphatase and parathyroid hormone concentrations, decreased urinary calcium and increased urinary hydroxyproline excretion, and decreased bone mass. Although the KG and AD groups demonstrated similar reductions in serum 25OHD concentration, the KG patients exhibited a significantly greater reduction in bone mass. In response to vitamin D supplementation (5000 IU/day), mean bone mass in the KG group increased by 8.1±0.9% (P〈0.001) over a 12-month period. These results suggest that ketogenic diet and anticonvulsant drug therapy have additive deleterious effects on bone mass and that these effects are partially reversible by vitamin D treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441213
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  • 13
    Electronic Resource
    Electronic Resource
    Effects of osteoclast activating factor from human lymphocytes on cyclic AMP concentrations in isolated mouse bone and bone cells (1979)
    Springer
    Calcified tissue international 28 (1979), S. 23-32 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Bone cells ; Cyclic AMP ; Osteoclast activating factor ; Lymphokine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Osteoclast activating factor (OAF) is a lymphokine which may participate in the pathologic destruction of bone observed in a number of disorders. In the current studies, we investigated the action of OAF on cAMP accumulation by bones and isolated bone cells in culture. OAF was shown to stimulate accumulation of cAMP in mouse cranial bones at doses between 1 and 1000 ng/ml. Stimulation of bone resorption was observed in bones treated with the same doses of OAF. In order to investigate the cell types responsible for cAMP responses to OAF, we isolated bone cells and grew them in monolayer culture. The cells were isolated by a variety of techniques which separate bone cells into two types of parathyroid hormone (PTH)-responsive populations: (a) cells derived from the periosteal regions of the bone, which also respond to calcitonin with increases in cAMP; and (b) cells derived from the matrix, which do not respond to calcitonin. OAF caused elevation of cAMP levels in both the periosteum-derived cells and the matrix-derived cells. The magnitudes and time courses of OAF effects in these populations resembled the effects previously reported for PTH in the same populations. OAF stimulated adenyl cyclase in both types of cell populations, but did not produce significant changes in cAMP phosphodiesterase activity. OAF differed from PTH in that its effects on cAMP accumulation decreased sharply at supramaximal doses in both bone and isolated cells, especially in the matrix-derived populations. Bone resorption did not decrease as markedly as did cAMP accumulation at high doses of OAF, suggesting that cAMP accumulation and resorption could be dissociated under some conditions. These results indicate that OAF has effects on cAMP production in the same cell populations as PTH, and suggest that OAF could modify not only resorption but also formation of bone in vivo. OAF may exert its effects on bone by means of cAMP-dependent mechanisms, but more data will be necessary to establish this unequivocally. The observed differences between OAF and PTH may be of relevance in the mechanism and treatment of pathologic bone destruction in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441214
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  • 14
    Electronic Resource
    Electronic Resource
    Bone metabolism, parathyroid hormone, and calcitonin in paraplegia (1979)
    Springer
    Calcified tissue international 27 (1979), S. 199-204 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Parathyroid hormone ; Calcitonin ; Osteoporosis ; Paraplegia ; Hydroxyproline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In paraplegia, osteoporosis below the neurological lesion occurs early after the spinal cord affection. The serum levels of parathyroid hormone (PTH) and calcitonin (CT), using a radioimmunoassay for the measurement of immunoreactivity, were studied in 12 paraplegic patients for 9 months following onset. Serum Ca and P levels, urinary hydroxyproline excretion, and the kinetic metabolic clearance of45Ca have also been measured. P and immunoreactive (i) CT levels were found the highest at the beginning of the observation and progressively decreased with time. Ca and iPTH serum levels varied inversely with time, the highest level of Ca and the lowest level of iPTH being recorded at the third month following the paraplegia. Mean values of Ca, iPTH, and iCT were in the normal range throughout the study. P levels were increased during the first 3 months. Hydroxyprolinuria was also high and45Ca kinetics showed increased values of Vt, Vo+, and Vu. These parameters indicate a high degree of bone turnover. The results were consistent with the assumption that PTH is not responsible for the increased resorption of bone in paraplegia. Likewise, a deficiency of CT does not seem to be responsible for this bone resorption. These endocrine modifications could be secondary to an increase in the calcium flux from bone to blood and resulting from bone destruction as attested by the increase of urinary calcium and urinary hydroxyproline excretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441186
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  • 15
    Electronic Resource
    Electronic Resource
    Bone maturation in the vitamin D, phosphate deficient rat and the response to acid loading (1979)
    Springer
    Calcified tissue international 27 (1979), S. 233-237 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Vitamin D ; Acidosis ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Vitamin D and phosphate deficiency were produced in rats in order (a) to evaluate the degree of bone mineral and matrix maturation using a bromoform/toluene density gradient technique; and (b) to compare the aforementioned bone maturational changes due to vitamin D and phosphate deprivation to those produced with superimposed severe acidosis. Rats were fed a diet deficient in vitamin D and phosphorus (0.2%) from 3 weeks through 7 weeks of age. To examine the additional contribution of dietary calcium, we gave one-half of the animals either a low (0.06%) or high (1.3%) calcium diet. Following the 4 weeks of vitamin D deficiency, one-half of each group was given 1.8% NH4Cl in the drinking water for 4 succeeding days to induce an acute, severe acidosis. The degree of bone maturation was quantitated via bromoformtoulene density gradient fractionation; total mineral and hydroxyproline (collagen) levels were quantitated as well. The vitamin D-deficient rats deprived of adequate dietary phosphate responded by conserving phosphorus, and as a consequence total bone phosphorus levels were maintained within that level for control rats. This conservation was independent of calcium intake but was extremely sensitive to acute acid loading, where a significant reduction in total bone phosphorus was noted. The bone maturational profile obtained from the vitamin D-phosphate deficient rats, however, revealed a significant accumulation of less mature or dense bone collagen and mineral with a corresponding decrease in the most mature or dense moieties. In contrast to the reduction of the total bone phosphorus content by acute acidosis, the skeletal collagen-mineral maturational profile was not significantly affected by the short-term systemic acidosis. The observed retardations in the bone collagen and mineral maturation of the vitamin D-deficient, phosphate-deprived state provide an additional observation which may well relate to the progressive osteopenia documented in states of chronic, mild acidosis.
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    URL: http://dx.doi.org/10.1007/BF02441191
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  • 16
    Electronic Resource
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    Changes in proline synthetic and degradative enzymes during matrix-induced cartilage and bone formation (1979)
    Springer
    Calcified tissue international 27 (1979), S. 275-279 
    Details
    ISSN: 1432-0827
    Keywords: Proline ; Cartilage ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Proline biosynthetic and degradative enzymes are unevenly distributed in differentiated mammalian tissues. Activities of the synthetic enzymes are relatively high in collagenous tissues, whereas activities of the degradative enzymes are high in noncollagenous tissues. In order to further characterize tissue-specific proline biosynthesis and degradation, we have determined proline enzyme activities during cartilage and bone formation induced by demineralized bone matrix. We can thus follow temporal changes in enzyme activity in a single tissue as different cell types develop. Ornithine aminotransferase and pyrroline-5-carboxylate reductase have peaks of activity which correlate with maximal type II collagen synthesis by chondrocytes. Both enzymes also are active during bone formation. In contrast, proline oxidase and pyrroline-5-carboxylate dehydrogenase are present at low levels and do not change as new cell types appear. Arginase activity peaks during the first 3 days and then rapidly decreases by the time cartilage and bone formation begin. These observations further substantiate the importance of proline biosynthesis in collagenous tissues. The close correlation between ornithine aminotransferase activity and type II collagen synthesis suggests that the pathway from ornithine to proline may be especially important during formation of type II collagen.
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    URL: http://dx.doi.org/10.1007/BF02441197
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  • 17
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    Noninvasive measures of bone bending rigidity in the monkey (M. nemestrina) (1979)
    Springer
    Calcified tissue international 27 (1979), S. 109-115 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Bending rigidity ; Disuse atrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The in vivo bending rigidity and bone mineral content of monkey ulnae and tibiae were measured. Bending rigidity in the anteroposterior plane was measured by an impedance probe technique. Forced vibrations of the bones were induced with an electromechanical shaker, and force and velocity at the driving point were determined. The responses over the range of 100–250 Hz were utilized to compute the bending rigidity. Bone mineral content in the cross section was determined by a photon absorption technique. Seventeen male monkeys (Macaca nemestrina) weighing 6–14 kg were evaluated. Repeatability of the rigidity measures was 4%. Bone mineral content was measured with a precision of 3.5%. Bending rigidity was correlated with the mineral content of the cross section,r=0.899. Two monkeys were evaluated during prolonged hypodynamic restraint. Restraint produced regional losses of bone most obviously in the proximal tibia. Local bone mineral content declines 17 to 24% and the average bending rigidity declines 12 to 22%. Changes in bones leading to a reduction in mineral content and stiffness are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441171
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  • 18
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    Anticonvulsant drug-induced osteomalacia: Alterations in mineral metabolism and response to vitamin D3 administration (1979)
    Springer
    Calcified tissue international 27 (1979), S. 13-18 
    Details
    ISSN: 1432-0827
    Keywords: Anticonvulsants ; Calcium ; Vitamin D ; Parathyroid hormone ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Parameters of mineral metabolism were examined in 6 patients with moderately severe anticonvulsant drug-induced osteomalacia. Compared to 15 matched controls, the patients exhibited significantly reduced serum calcium, inorganic phosphate, and 25-hydroxyvitamin D concentration, elevated serum alkaline phosphatase and immunoreactive parathyroid hormone (iPTH) concentration, reduced intestinal47Ca absorption, reduced urinary calcium and increased urinary hydroxyproline excretion, and reduced forearm bone mass. Intestinal absorption of vitamin D3 was normal. Following 4 months of treatment with vitamin D3 (4000 units/day), serum 25-OHD concentration was increased to 3 times mean normal values and all parameters except serum iPTH, urinary calcium excretion, and forearm bone mass were returned to levels not significantly different from normal. Serum iPTH concentration was reduced by 39% (P〈0.05); 24-h urinary calcium excretion rose by 98% (P〈0.001), and forearm bone mass increased by 5.6% (P〈0.05). It is concluded that moderate-dose vitamin D3 supplementation is effective in normalizing parameters of mineral metabolism in this disorder, despite evidence of resistance to the biologic effects of vitamin D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441155
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  • 19
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    The calciuria of increased fixed acid production in humans: Evidence against a role for parathyroid hormone and 1,25(OH)2-vitamin D (1979)
    Springer
    Calcified tissue international 28 (1979), S. 233-238 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; PTH ; 1,25(OH)2D ; Acid ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We measured mineral and acid balances, serum iPTH, urinary cAMP/creatinine, and plasma concentrations of 25OHD and 1,25(OH)2D in 7 healthy adults during control conditions and during increased fixed acid production achieved either by the administration of NH4Cl (N=3) or by increased dietary protein intake (N=4). When acid production was increased, the subjects were in positive acid balance and negative Ca balance because of increased urinary Ca excretion. Serum iPTH fell slightly but urinary cAMP and the plasma levels of vitamin D metabolites did not change. We conclude that the accelerated skeletal and urinary losses of Ca that occur when fixed acid production is increased are not contributed to nor compensated for by the parathyroid-vitamin D endocrine systems.
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    The occurrence of chondroitin-6-sulphate in adult human compact bone tissue (1979)
    Springer
    Calcified tissue international 29 (1979), S. 169-171 
    Details
    ISSN: 1432-0827
    Keywords: Glycosaminoglycans ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Compact bone tissue chondroitin sulphate, previously considered to be pure chondroitin-4-sulphate, was isolated from three adult human femoral diaphyses and digested with chondroitinase ABC. Assaying these digests by means of high performance liquid chromatography we could demonstrate that 12 to 14% of the disaccharide residues were 6-sulphated. The 4/6-ratios were also studied in chondroitin sulphate fractions of different molecular size. Slightly increasing amounts of 6-sulphated disaccharides were found with increasing size of the chondroitin sulphates.
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    URL: http://dx.doi.org/10.1007/BF02408073
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    Effects of changing hydrogen ion, carbonic acid, and bicarbonate concentrations on bone resorption in vitro (1979)
    Springer
    Calcified tissue international 29 (1979), S. 7-13 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Culture ; Resorption ; Acidosis ; Alkalosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have examined the effects of H+, CO2, and HCO3 − concentrations during metabolic and respiratory acidosis and alkalosis on bone resorption in vitro. Rat fetal bones prelabeled with45CaCl2 were cultured at 2%, 5%, and 10% CO2 for up to 120 h, and the release of45Ca was measured in devitalized bones (non-cell-mediated45Ca release) and in live bones (cell-mediated45Ca release) cultured with or without PTH and 1,25(OH)2D3. Non-cell-mediated mineral loss was linearly related to H+ concentration but not to CO2 or HCO3 − concentration. This effect was observed on both labeled and stable calcium. Over a wide pH range (6.9–7.5) H+, CO2, or HCO3 − concentrations did not influence cell-mediated bone resorption in control or in PTH-and 1,25(OH)2D3-stimulated cultures. However, inhibition of cell-mediated bone resorption was observed at higher or lower pH irrespective of CO2 or HCO3 − concentrations. These observations demonstrate that the bone mineral mobilizing effect of acidosis in vitro is mainly due to the effect of changing H+ concentration on devitalized bone. Effects on cell-mediated bone resorption and hormonal response were observed only at extremes of pH. The effects of H+ were independent of changes in CO2 or HCO3 − concentration and could be responsible for the negative calcium balance and increased urinary loss observed in metabolic acidosis in vivo, but do not explain the reported differences in effects on calcium metabolism between respiratory and metabolic acidosis.
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    URL: http://dx.doi.org/10.1007/BF02408049
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    Recent studies of rubberlike elasticity (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 87-97 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New synthetic techniques are now available for the preparation of “model” polymer networks of known and carefully controlled molecular structure. The preparation of such networks and their utilization in elucidating molecular aspects of rubberlike elasticity are illustrated using highly elastomeric, unfilled networks of polydimethylsiloxane. In one such preparative technique, hydroxyl-terminated chains are end-linked using either a tetrafunctional or trifunctional silicate, in either the undiluted state or in solution. Because of the selectivity and completeness of the reaction, the molecular weight and molecular weight distribution of the network chains are to good approximation those of the chains prior to their end-linking into the network structure. The experimentally determined stress-strain isotherms and degrees of equilibrium swelling of the resulting networks are then used to evaluate the molecular theories of rubberlike elasticity, particularly with regard to the dependence of the elastic modulus and ultimate properties on the degree of cross linking and the cross-link functionality. Another preparative technique employs random and block copolymers containing reactive vinyl groups in known amount and known distribution along the chains. Selectively cross-linking through these sites then yields model networks ranging from random to highly non-random in chain length distribution. These networks are particularly useful for characterizing the effects of very short chains on the average degree of cross-linking or average network chain length as obtained from stress-strain and swelling equilibrium measurements.
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    Photocrosslinkable polymeric systems and their technical applications (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 169-188 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 24 Ill.
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    Interaction of synthetic polymers with components of the living materials (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 215-231 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some examples of interaction between various soluble and crosslinked synthetic polymers and physiological environment and its constituents are exemplified and discussed. Our view is confronted with several typical published data and is also illustrated by few original results.
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    Cationic ring-opening polymerization (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 17-39 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Advances in the major areas of the cationic ring-opening polymerizations are discussed. In the first part synthesis of new polymers is reviewed; this includes mainly novel block and graft copolymers based on the di- and multicationically ended living polyacetals and polyethers (polyTHF).Recent data on thermodynamics of nonideal systems, giving dependence of [M]e on [M]o, are summarized with special emphasize of the differences between monomers due to variation of their nucleophilicities.Discussion of kinetics and mechanisms of polymerization of cyclic acetals and ethers is focused on the macroring formation and reactivities of active centers.The reactivity of covalent and various ionic growing species are compared in the polymerization of cyclic ethers (THF and oxepane) and oxazolines. Reasons for much lower reactivity of covalent than ionic species and reasons for similar reactivities of macroion-pairs and macroions are presented.It is shown, that the kinetically controlled proportions of macrorings in the polymerization of these and other heterocyclic monomers depend on the structure of the end-groups, formed upon initiation. Initiation with acids, giving H-X∼ (where X=heteroatom) end-groups, leads to the kinetically enhanced proportion of macrorings. This is particularly important for the low degrees of polymerization.
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    Immobilized enzymes - semisynthetic catalysts (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 107-127 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The immobilization of various enzymes, mainly of hydrolases, by carriers with e.g. maleimide, benzoquinone, N-substituted sulfamic acid, and diazonium groups will be described. As basic polymer mainly poly(vinyl alcohol) was used which was derivatized. The immobilization of enzymes was performed also with synthetic wood pulp. The influence of unfolding of the enzyme chains during the immobilization reaction on the characteristics of the immobilization products as well as the influence of the spacer length on the immobilization was investigated. An example of a soluble immobilized trypsin product is given. Some aspects of the characterization of immobilized enzymes will be discussed. Also some examples of whole cell immobilization as well as of application of immobilized enzymes and immobilized whole cells will be described.
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    Monomer-monomer interaction in spontaneous initiation and sequence regulation in copolymerization (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 157-176 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The monomer-monomer interaction plays important roles in many cases of alternating copolymerizations. This article describes first a review of alternating copolymerizations in terms of the varieties of the types of reactions, the types of monomers, and the combinations of monomers. The reactions of alternating copolymerizations are classified into the following five types; (i) free radical alternating copolymerization involving polar vinyl monomers (Type-1), (ii) free radical alternating copolymerization between olefins and acrylic monomers with the assistance of Lewis acids (Type-2), (iii) alternating copolymerization of olefins and diolefins with Ziegler-Natta catalysts (Type-3), (iv) ring-opening copolymerization of heterocyclic monomers (Type-4), and (v) spontaneous alternating copolymerization via zwitterion intermediates (Type-5). The monomers which have been involved in alternating copolymerizations are polar vinyl compounds, mono-olefins, diolefins, heterocyclic compounds, SO2, CO2 and isocyanates. Then, the general patterns of the mechanisms of sequence control were described, and the detailed mechanisms were discussed in the copolymerizations of Types-1, -2 and -5 in which the monomer-monomer interaction has been reported to be responsible for the initiation and the sequence regulation.
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    Some physical properties of polymer solutions and melts (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 195-196 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Many properties of semi dilute and concentrated polymer solutions can be understood simply in terms of certain scaling laws (1). In the first part of this talk, we present scaling results for various problems connected with colloid science. (1) Near a solid wall (or an interface) when the chains are not adsorbed at the interface, a polymer solution is expected to show a depletion layer of sizeable thickness near the wall (2). (2) The existence of these layers may induce an attraction between colloïdal grains suspended in the solution. This attraction can lead to flocculation when the grain radius b is larger than the correlation length ζ(c) of the solution; in the opposite limit (b 〈 ζ) the attraction is weak (3). (3) We discuss the entropy of polymer chains confined in very narrow tubes of diameter D. For a single chain in a good solvent this problem has been understood sometime ago (4), but for chains in a melt the situation is surprisingly different (5). (4) Freely suspended liquid films occurring for instance in foams should be often stabilised by the addition of long polymer chains (always assuming no adsorption on the limiting surfaces) : the chains lose entropy by confinement, and the result is a stabilisation free energy (per cm2 of film) varying like the inverse film thickness (6).In the second part of the talk, we discuss some aspects of the motions and flows of entangled systems. (1) The cooperative diffusion of the polymer through the solvent (or vice versa) does not involve disentanglements and is amenable to simple scaling laws (7) which have to some extent be confirmed by photon beat experiments (8). It must be emphasized, however, that these laws are valid asymptotically for long chains, in very good solvents, and in a semi dilute regime where the chains do overlap, but where the concentration is still low enough, so that the friction processes are still dominated by the solvent viscosity (as opposed to monomer-monomer friction) : these limitations have not always been appreciated in the literature. (2) The simplest experiment displaying entanglements is based on viscometric flows at low shear rates. However, it has been recently realised that in many practical cases the standard boundary conditions - of zero slip at the walls - do not apply to these flows (9); when the wall is reasonably flat, and does not build strong links with the polymer, the friction forces involved in a finite slip are much weaker than the viscous stresses inside the polymer solution. This must, for instance, lead to strong deviations from the Poiseuille law in a capillary, whenever the tube diameter D is smaller than a characteristic length (of order 0.5 mm in typical cases). (3) A different approach is based on the studies of individual diffusion D* of a labeled chain, for which the reptation model (10) predicts a dependence of the form D* ∼ M-2 on molecular weight. Various systems have been used to measure D* (11) : here the emphasis will be on recent data using the stimulated Rayleigh effect (12) which is particularly well suited for slow diffusion.
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    Mechanical and dielectric investigations of relaxations in polymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 247-275 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamics of polymer melts is well reflected in the complex shear compliance J*(ω,T,M) measured in wide ranges of frequency and temperature and for various molecular weights. In the frame of the meander model all typical features of J*(ω,T,M) are quantitatively described: (1) JeNo is due to intra-meander shear, and decreases by incorporating pairs of chain ends within the superstructure folds, i.e. with decreasing M. (2) This shear motion is guaranteed by a certain amount of edge-dislocations (with Burgers vector b equal to the chain distance d- for some polymers equal to d/2). The glass relaxation and its activation diagram are understood by asking for the probability for just this amount of dislocation segments to be present. The dielectric relaxation strengths and those of the thermal properties support the chosen segment lengths. (3) The step height to the steady state compliance, Jeo - JeNo (proportional to JeNo above MC, but strongly dependent on M-distribution), is due to inter-meaner shear (formation of shear bands). (4) These bands relax by disentanglement via chain reptation across half the length of a molecule within the flow relaxation time τF. (5) The Viscosity follows from η = τF/Δeo, and is proportional to M3.3 above and M1.3 below Mc. (6) The critical molecular weight Mc is predicated by the model in fair agreement with experimental data.(7) Neglecting flow, the stress-strain curves of uncrosslinked high molecular weight polymer metals can be derived by taking into account intra-and inter-meander shear deformation.
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    New initiation systems for cationic polymerisation (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 348-358 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experimental results are presented to show that suitable free radical sources, in combination with aryldiazonium, diaryliodonium, and triarylsulphonium salts, may be used to promote cationic polymerisation of alkyl vinyl ethers and cyclic ethers and cyclic ethers such as tetrahydrofuran. Mechanistic features vary between the different classes as monomer but a general feature is a free radically initiated chain reaction leading to formation of initiating or propagating cationic centres. The process is especially weil suited to use of photochemically active free radical sources and, for polymerisation of tetrahydrofuran, it is shown that at least thirty propagating cations are produced for each photon of light absorbed byu the free radical initiator β,β-dimethoxy-β-phenylacetophenone. Product studies confirm that the initiating free radicals undergo electron transfer oxidation.
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    Copolymerization of 1-vinylindol with maleic anhydridePaper presented in part at the 2nd Meeting of AISTM (Italian Association of Science and Technology of Macromolecules), Milano, December 13-15, 1976. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 13-24 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of a charge-transfer complex between 1-vinylindole (1a) and maleic anhydride (MA) was detected by 1H NMR analysis, and the corresponding Keq was measured (Keq=0,251 mol in CDCl3 at 25°C). It could be shown that this complex can be involved both in the initiation and propagation steps of the 1a-MA copolymerization by carrying out spontaneous copolymerization experiments and studying the influence of the feed composition on the conversion and [η] of the copolymer. The structure of the 1a-MA copolymer, investigated by 13C NMR spectroscopy, was found to be complicated due to the formation of indoline rings along the chains by an attack of the propagating MA radical at position 2 in the indole ring. As a consequence an excess of MA, with respect to a 1:1 mole ratio of monomer feed, was usually found in the copolymer. The mechanism of the cyclization reaction was clarified by copolymerizing MA with 2-methyl-1-vinylindole (1b), 3-methyl-1-vinylindole (1c), or 2,3-dimethyl-1-vinylindole (1d). An alternating copolymer with MA (mole ratio 1:1 of monomeric units), without irregularities, was obtained only by employing 1d as a comonomer.
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    Crosslinking and networks (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 35-49 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Theoretical treatments of network formation and the applicability of the tree-like models to the calculation of structural parameters in the post-gel state and to more complex systems of practical importance are discussed. The unseparability of structural interpretation of network properties from network formation is stressed.
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    A transparent multiparameter approach to structural recovery of glasses (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 81-86 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The characteristic fetures of isobaric volume and enthalpy recovery of glasses are briefly recalled and analysed in terms of a multiparameter model involving a distribution of retardation times, τi. The latter are assumed to depend both on temperature and on the instantaneous state (structure) of the glass, whereas the shape of the retardation spectrum is invariant and merely shifts, as τi, along the logarithmic time scale. Qualitative comparison of the theoretical predictions with various types of experiment reveals an excellent agreement. Some effects of structural recovery on the mechanical, or electrical properties of polymer glasses are also recalled and discussed in terms of the theoretical model The text which follows is merely an extended abstract of the work published elsewhere (see Refs 5 & 10)..
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    Structure and properties of crystalline polymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 155-167 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recent advances and status of x-ray structure analysis of crystalline polymers are described using examples of α-modification of poly(ethylene oxybenzoate), poly(ethylene oxide), isotactic poly(methyl methacrylate), and cellulose I. Next the relationship between crystal structures and crystallite moduli (one- and three-dimensional) is discussed. Finally vibrational free energies of two crystal modifications of polyethylene are derived and discussed.
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    Recent developments in the fracture mechanics of polymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 189-206 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The author's Generalized Theory of Fracture Mechanics has been applied to several quite different polymeric materials which have in common a non-linear and inelastic deformation behaviour. Thus the normal Linear Elastic Fracture Mechanics cannot be applied. When applied to experimental data the theory provides a unique characterisation of fracture resistance and also sheds light on the molecular or microscopic fracture mechanisms of the material concerned.
    Additional Material: 9 Ill.
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    Sequential copolymers by ionic polymerizations (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 1-16 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: While many well defined sequential copolymers have been synthesized by anionic and some by coordination polymerization techniques, cationic methods have not been exploited in this regard. This lecture focuses on “macromolecular engineering” by cationic techniques and summarizes the many recently developed and largely unpublished methods by which a great variety of sequential copolymers and modified polymers can readily be prepared. A new scheme for macromolecular engineering by carbocationic mechanism is proposed. Controlled initiation as a means of introducing head-groups into polymers or of graft-copolymer syntheses is described. Control of chain transfer to monomer became possible by the use of bifunctional initiator-chain transfer agents (inifers) or by proton sponges. The synthesis of telechelic α,ω-dichlorides, and -diolefins is outlined. α,ω-(Di-tert-chloro) polyisobutylene, a new symmetrical telechelic prepolymer has been used to prepare poly(α-methylstyrene-isobutylene-α-methylstyrene) thermoplastic elastomeric triblocks. Consequences of controlled termination are illustrated by the synthesis of diblock copolymers. Finally, by a combination of mechanistic elements, a system for macromolecular engineering by cationic techniques is outlined.
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    Stereochemistry of ring opening polymerization of chiral monomers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 69-83 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stereospecific polymerizations of racemic mixtures of chiral cyclic monomers have been shown to be stereoselective with non chiral initiators and stereoelective with some chiral initiators.The bulkiness of the ring substituents influences the interaction of monomer with initiator and this leads to various kinetic schemes for stereoelective reactions, that may give efficient kinetic resolution of the monomer. In some cases a very strong effect of optical purity of monomer is observed in non racemic systems.Monomers having two chiral groups in the ring may be polymerized by an asymmetric polymer synthesis, giving optically active polymers starting from meso compounds.An analysis of several stereoelective processes leads to the conclusion that the monomer enantiomers play a major part in determining the chirality of the active centres.
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    Kinetics of copolymerization (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 129-156 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In comparison to the number of publications on composition and structure of copolymers, there are only a few publications on the kinetics of radical copolymerizations. The equation by Melville and Walling is a first attempt to describe the kinetics. It was derived using the assumption that termination is chemically controlled. Since the 1960s it has been realized that in the case of radical polymerization reactions the chain termination is controlled by diffusion. Based on this knowledge Atherton and North developed a rate equation from which a termination constant can be ascertained from each monomer mixture composition. Russo and Munari continued North's works. They showed that the copolymerization rate can be adequately described if one assumes that the last two monomer units in the chain radical determine its segment flexibility. Apart from the constants known from the corresponding homopolymerizations the equation of Russo and Munari contains two other parameters, which are linearly connected. This equation was used in a discussion on copolymerization reactions in a homogeneous continuously stirred tank reactor (HCSTR). In this context the attainment of the steady state after disturbing input and output of the reactor was investigated.
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    Stress relaxation in solid polymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 233-245 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The behaviour of polymers during stress relaxation at constant deformation is discussed. Special interest is devoted to the kinetics of the relaxation process and its physical interpretation. The various theories used in this field are compared, this comparison including in the first hand the theory of relaxation-time spectra and stress-aided thermal activation. Some discrepancies associated with these theories are pointed out, for instance the particular way in which the activation volume depends on the effective stress. Cooperatives effects are considered as a possible explanation of experimentally observed facts, especially with regard to the similarities in the stress relaxational behaviour of polymers and other solids, as for instance metals.The concept of effective stress incorporating the internal stress level is shown to be of primary importance in this context.
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    Transport phenomena and polymer morphology (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 215-232 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The presence of the crystals in the semicrystalline polymer reduces the mass fraction, determines the space distribution and modifies the transport properties of the amorphous component which is responsible for practically all the sorption, diffusion, and permeability. The conventional determination of the diffusion coefficient from the sorption or diffusion transient is strongly affected by the geometry of the sample. The spin echo method of the nuclear magnetic resonance in a pulsed magnetic field gradient measures the diffusion directly and hence reflects the anisotropy of the orientation of the amorphous component without any distortion by the shape of the sample. The anisotropy of a single amorphous layer of a thickness of less than 10 nm, however, cannot be detected by this method which measures the molecule displacement over about 300 nm.A very rough estimate of the transport properties of the volume element can be based on the fractional free volume of the polymer. This is particularly helpful in the description of the effects in elastically and plastically deformed material. The elastic tensional strain increases while the plastic strain as a rule decreases the free volume. In the latter case the amorphous component, at least at room temperature, permanently deviates from the thermodynamic equilibrium. A substantial part of this deviation can be removed by annealing. If the annealing of the fibrous material is performed with fixed ends which prevents shrinking the sample upon standing at room temperature tends to return, at least partially, to the transport properties before annealing.The sorption is proportional to the mass fraction of the amorphous component, the permeability to the square of it. The diffusion reflects the anisotropy of the morphology and of its influence on the transport properties of the amorphous component. In the fiber structure the amorphous layers parallel and perpendicular to the fiber axis differ substantially.In spite of the close connection between the morphology and the transport properties one must not forget that this connection is one-sided. A model of the structure with the proper transport parameters of the amorphous component has to yield the observed sorption and diffusion data. But these data are not sufficient for constructing unambiguously the structural model.
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    Recent studies of polymer degradation and stabilization (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 27-34 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Highlights of recent research on the degradation and stabilization of polyolefins and poly(vinyl chloride) are outlined. The major defects in the molecular structure of poly(vinyl Chloride) are described and some controversial aspects of polyolefien photochemistry are discussed.
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    Dynamic light scattering from polymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 73-80 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Applications of both polarized and depolarized dynamic light scattering to the study of polymers are described. Polarized light scattering is used to study translational diffusion, diffusion virial coefficients, rotational motion of long rod-shaped polymers, long-wavelength intramolecular motions, dynamics of pseudogels and gels and density fluctuations in bulk polymers. Depolarized scattering is used to study rotational diffusion of rigid macromolecules, local and long-wavelength intramolecular motions, dynamics in semi-dilute solutions, rotational motions of small molecules in glassy polymers and optical anisotrophy fluctuations of bulk polymers.
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    “Lamellar and fibrillar crystallization of polymers” (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 99-142 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 22 Ill.
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    The solid polymeric state: Thermodynamic and relaxational aspects (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 143-154 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The statistical thermodynamics of the melt and the crystal are discussed by a unified approach which distinguishes between the two phases only in terms of a structure function minimizing the configurational free energy. The ensuing equations of state at atmospheric and elevated pressures are compared with typical experimental data for polymer and oligomer melts, and crystalline as well as semicrystalline systems, with satisfactory results. As to the glassy state, expansivity data clearly reflect nmot only the glass transition, but also sub-glass relaxation processes. In the spirit of the preceding discussion of the equilibrium melt, quasi-thermodynamic conditions are considered. Here the non-equilibrium character is reflected in the dependence of the extensive thermodynamic functions on thermal history in addition to the ambient variables of state. This state is discussed in terms of modifications of the liquid state model.
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    Affinity therapy and polymer bound drugs (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 2 (1979), S. 207-214 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some of the principles and advantages of affinity and polymeric drugs are demonstrated by the coupling by various methods of the anti-cancer drug daunomycin to antibodies against cancer cells and to dextran. In all the cases studied the conjugated drugs retain a significant amount of the original drug activity, and were less toxic. At higher concentrations the conjugated drug was more potent due to the lower toxicity. The mechanism of the action of the polymeric drugs are not yet known. We assume that they work through a slow release of the low molecular weight drug.
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    Some new aspects of polymerization reaction (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 41-68 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: This paper deals with general and also specific aspects of matrix polyreactions on macromolecular templates, namely, mutual assistance of active centres of propagating chains and template units in elementry steps of propagatior. Such assistance has been found in polymerization of 4-vinylpyridine on polyacids and propargyl compounds on poly-4-vinylpyridine. These examples have shown that these kinds of assistance are the crucial points in kinetic template effects.
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    Macromolecular photochemistry (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 85-106 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Different modes of interaction between the realm of photochemistry and photophysics and the domain of polymer chemistry are discussed. A distinction between photoinitiation and photopolymerization is drawn on the basis of the role of the excited state either in the chain starting or chain-growing process. Attention is drawn to specific properties or problems in the photochemistry and photophysics of macromolecules. The influence of neighbouring groups, high local concentrations etc. are discussed in relation to polymer transformation and excimer formation.
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    Dispersion polycondensation (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 177-193 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: A survey is given on the actual knowledge about kinetics and mechanism of the synthesis of aromatic polyamides by dispersion polycondensation. Chemical activation of the reactants and swelling phenomena play an important role in this fast proceeding process. Molecular weight distribution of reaction products deviates from the most probable distribution.
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    Phase equilibria in multicomponent polymer mixtures (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 197-214 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In recent years thermodynamic equilibrium properties of amorphous polymer blends have been the subject of increasing interest. Experimental techniques, known in the study of polymer solutions, have been applied to blends and have been modified to deal with highly viscous systems. Determination of critical points, spinodal and cloud-point curves are now well possible by means of a low-speed centrifuge, pulse induced critical scattering and the centrifugal homogenizer.The classic Flory-Huggins model cannot describe the experimental results. Improvements can be made by the introduction of the contact surface areas of the segments, and by correcting the combinatorial entropy of mixing for orientational effects related to chain flexibility. Two-peaked spinodals may furthermore be described with a model accounting for three concentration ranges in the blend, the two dilute solutions of one polymer in the other and an intermediate range of uniform segment density. As a third possibility the introduction of holes in the lattice (simple lattice gas) can also lead to qualitatively correct descriptions, even in those cases where the phase diagram is still more complex (system poly(styrene-co-acrylonitrile)/polymethylmethacrylate) and shows three miscibility gaps.Strictly-binary polymer mixtures with a bimodal cloud-point curve should show two stable critical points. The fact that we did not find more than one may be attributed to polydispersity which easily shifts one of the critical points into the experimentally inaccessible meta-stable region.
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    Thermodynamics of crystallizing oligomer and polymer multi-component systems (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 277-318 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crystallization seggregation of chain ends and chains is always observed in oligomer multi-component systems. The driving forces of these processes can be classified by use of the thermodynamics of eutectoid systems. If folded-chain crystallization does not appear, a defined relationship between the chain length-and the crystal thickness distributions is predicted with its typical influence on the melting transition.With local equilibrium there is the opportunity for a quantitative description of the melting transition of eutectoid copolymers of ethylene by means of the same thermodynamics as used for the oligormers in spite of the existing crystal newtork. There is only need of taking into consideration a varied solubility in the microphases. Swelling phenomena are treated quantitatively on the same lines, thus, yielding the same relationship between the length distribution of the crystallizable sequences and the crystal thickness distribution as in the pure copolymeres.The melting transition is shown to depend on the swelling deformation in the non-crystallized regions which gives direct evidence for the existence of the molecular crystal network. Hence, local crystallization seggregation of non-crystallizable units is found to be in principles present in all the systems involved, thus, indicating its general importance.
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    NMR - studies on conformation and dynamics of macromolecules with emphasis on their configuration (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 319-326 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1Capabilities and limitations of methods for the determination of unperturbed macro - conformations in Θ - solutions as well as in metls and glasses are discussed, especially concerning the consequences for the micro-conformations. Quasi - isoenergetic polymer chains are concluded from thermolastic measurements on a configurätional copolymer.2Temperature dependent NMR- chemical shift measurements - beside those of coupling constants - are proposed for an independent determination of the micro - conformation on at a segemental level. Their populations are calculable from slow as well as from fast exchange spectra. Macro- dimensions as well as their temperature dependence as the consequence of the micro - conformations.3The dynamics of macromolecular chains - especially the anisotropy of motion - are discussed from NMR data.4The mechanism of stereospecific polymerizations as a consequence of conformational arrangements is discussed from NMR measurements.5Approaches to interpret thermal and mechanical data from configuration and conformation are reported.A short survey of the IUPAC lecture is presented, since detailed interpretation of the scientific work discussed either is given in the literature or will be published in the near future.
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    Polymérisation et copolymérisation d'acétoxy-2 alcadiènes-1,3 - l'acétate de (cyclopentène-1 yle)-1 vinyle et l'acétate de (méthyl-3 butadiène-1,3) yle- 2 - formation des polycétones correspondantes (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 79-88 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of 1-(1-cyclopentenyl)vinyl acetate (1) and (3-methyl-1,3-butadien-2-yl) acetate (7) under radical conditions, leading to 1,4-polymers, and the copolymerization with vinyl monomers were studied. The reactivity ratios are compared with those previously described for some acetoxydienes. Polyketones and copolyketones were obtained by alkaline hydrolysis of the polymers of 1 and 7 and copolymers of 1 and 7 with styrene.
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    Synthesis of a cationic polyelectrolyte by successive quaternization of 1,4-bis(2-diethylaminoethyl)benzene (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 65-77 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: 1,4-Bis(2-diethylaminoethyl)benzene (4), synthesized from 1,4-divinylbenzene (1) and diethylamine (2) with lithium diethylamide as catalyst, was successively quaternized with 1,4-dibromobutane (5) to prepare a cationic polyelectrolyte 6 of the ionene type. Apparent molecular weights of the ionene samples were estimated by the sedimentation equilibrium method, and the result is discussed in connection with the true molecular weight. The rate constants for quaternization of first and second nitrogen atom of 4 (k1 and k2) were determined by the use of 13C NMR. It was found that the ratio of the rate constants, (k2/(k1/2)), markedly decreased in the 4/5 system, though it remained unity in the 4 ethyl bromide system.
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    Polymerization of lactams, 29Part 28: cf.15.. On the initial stage of the activated anionic polymerization of 2-pyrrolidone (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 89-95 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: The activated anionic polymerization of 2-pyrrolidone in the initial stage was studied at 30-70°C in the range of 1-60 min. Potassium tert-butoxide and N-benzoyl-2-pyrrolidone were used as initiator and activator, respectively. It can be seen from the polymerization process that side reactions occur parallel to the fast propagation reaction.
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    Homopolymerisation von styrol mit titan(III)-chlorid/alkylhalogenid-initiatoren (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 97-102 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of styrene initiated by titanium(III) chloride/alkyl halide redox systems was studied. Among the alkyl halides examined, the highest rate of polymerization was found in the system titanium(III) chloride/carbon tetrachloride. The polymerization rate can be described by the equation Rp=k·[Ti(III)]0,5·[CCl4]0,5·[St]1,0. The polymerization proceeded via a radical mechanism. The overall activation energy was estimated as 57,3 kJ/mol. It was found that titanium(III) chloride/chloroacetic acid systems, too, could initiate the polymerization of styrene.
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    Darstellung und eigenschaften von chelatharzen mit pyrazol-3,4-dicarbonsäure bzw. 1,2,3-triazol-4,5-dicarbonsäure als ankergruppen (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 103-115 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: N-vinylation of pyrazolecarboxylates and 1,2,3-triazolecarboxylates with vinyl acetate leads to the formation of the N-vinylpyrazoles and N-vinyl-1,2,3-triazoles. The structures are determined by mass and NMR spectra. The syntheses of crosslinked poly[1-(3,4-dicarboxypyrazol-1-yl)ethylene] (12) and poly[1-(4,5-dicarboxy-1,2,3-triazol-2-yl)ethylene] (13) are described. The swelling behaviour, the time dependence of the uptake of Cu2+-ions and the pH-dependence of the uptake of Cu2+-, Zn2+-, and Mg2+-ions of these resins were investigated.
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    Préparation et étude des propriétés chiroptiques de poly(tert-butyloxiranne)s optiquement actifs (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 131-146 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Optically active poly(tert-butyloxirane)s of various molecular weights were prepared by polymerization of R(-)-tert-butyloxirane with different initiators or by stereoelective polymerization of the racemic monomer. Using identical conditions of polymerization (initiator, temperature etc.) it was found that the pure enantiomer polymerizes much faster than the racemic monomer. The chiroptical properties of the obtained polymers showed similarities in behaviour with those of a synthetized linear model molecule representative for a monomeric unit of the polymer. The enhanced optical activities of low molecular weight polymers were correlated with the presence of chelated hydroxylic end-groups.
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    15N NMR spectroscopy, 13Part 12: cf. H. R. Kricheldorf, W. E. Hull, Org. Magn. Reson. in press.. Copolymerization of glycine-N-carboxyanhydride and β-alanine-N-carboxyanhydride (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 147-159 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In contrast to 13C NMR spectra, 15N NMR spectra allow one to characterize the sequence of copolypeptides built up by glycyl and β-alanyl residues, because the shifts of the Gly-Gly, β-Ala-Gly, Gly-β-Ala, and β-Ala-β-Ala bonds differ from each other by several p.p.m. Hence, the copolymerization of glycine-NCA and β-Alanine-NCA can be investigated by quantitative evaluation of the 15N NMR spectra obtained from the resulting copolymers. The copolymerization of these two amino acid NCAs initiated by primary amines leads to random sequences; the copolymerization is azeotropic in nature, and both copolymerization reactivity ratio parameters are near 1. If aprotic bases like pyridine and triethylamine are used as catalysts, the rate of incorporation of glycine is higher than that of β-alanine and the copolymers possess a block structure.
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    Mechanism of the polymerization of hexamethylcyclotrisiloxane (D3) in the presence of a strong protonic acid (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 117-130 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of hexamethylcyclotrisiloxane (D3) was studied in methylene chloride solution in the presence of trifluoromethanesulfonic acid as catalyst. The reaction occurs mostly by addition of monomer to the ends of growing molecular chains. However, an important role is played by cleavage of a siloxane bond in the monomer by acid or water as well as by reverse processes of silanol and/or +ylester end group condensation to siloxane linkages. The latter account for the formation of large amounts of cyclic products and for the coupling of linear chain fragments. They are also responsible for the regeneration of the catalyst leading to establishment of stationary concentrations of reactive species in the polymerization system.The involvement of the above mentioned processes of condensation and siloxane bond cleavage contributes to a dramatic change in kinetics of the polymerization with introduction of water into the reaction system. In particular, the polymerization when carried out without water addition shows three interconnected features: 1 Strong acceleration of the rate with addition of small amounts of water to the system. 2 An apparent negative value of the activation energy. 3 Increase of the rate with decreasing initial concentration of the monomer. Above a certain level of water content the polymerization rate is only slightly dependent on the concentration of water. The energy of activation is 50 kJ/mol and the reaction is of 1st order in monomer, internally as well as externally.
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    15N NMR spectroscopy 14Part 13: Cf.12. Neighboring residue effects in glycine-containing polypeptides (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 161-174 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The sequence polypeptides (Ala*-Ala-Gly)n, (Ala-Gly*-Gly)n, (Leu-Gly-Gly)n, (Val-Gly-Gly)n, and (Pro-Gly-Gly)n were synthesized by known methods, and their natural abundance 15N NMR spectra were measured in trifluoroacetic acid. These spectra were compared with those of other previously described sequence polypeptides and with the corresponding homopolypeptides. The spectra of all sequence polypeptides exhibit neighboring residue effects, so that glycine nitrogen atoms acylated by other χ-(or ω-)amino acids have chemical shifts different from that of the Gly-Gly bond. These neighboring residue effects cannot be summarized or explained by simple rules; however, they are useful for the characterization of copolypeptides. Such an application was tested in the case of four sequence polypeptides consisting of isomeric sequences of identical monomeric units. All isomeric sequences can be distinguished from each other, and the observed shift effects could be related to the neighboring residue effects of other copolypeptides.
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    Molecular weight dependence of magnetic circular dichroism for polystyrenes in solution (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 175-180 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The molecular weight dependence of the magnetic circular dichroism (MCD) for polystyrenes (PS) has been studied in various solvents by using the normalized dipole-strength D*. The normalized MCD intensity B* is not so much affected by the molecular weight as the normalized dipole strength D+. The ratio of the Faraday parameter to the dipole strength, B*/D*, decreases as the molecular weight increases to 4,0.103 and is constant above it. The increase of the normalized D* with the increase of molecular weight is interpreted in terms of the closer approach of chromophores. These results indicate that MCD for polystyrenes is influenced by the interaction of chromophores in a polymer chain: the decrease of B*/D* comes from the increase of the interaction of chromophores. This tendency is enhanced by solvent effects on MCD.
    Additional Material: 5 Ill.
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    Synthèse et caractérisation de copolymères coordinés par des sels métalliques (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 181-187 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The anionic block copolymerisation of isoprene and 2-vinylpyridine (2VP) followed by a coordination with iron (III) chloride, leads to thermoreversibly crosslinked copolymers. These copolymers are character+ed by a low polydispersity (M̄w/M̄w≈1,1) between the coordination nodules of poly(2-vinylpyridine). The study of the swelling ratio at the equilibrium in benzene shows that such a polymeric network does not reach the equilibrium state expected from the thermodynamic analysis of the system. The presence of 2VP in the copolymer induces a screening effect which prevents the solvent diffusion through the polyisoprene network.
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    Effects de la substitution du cycle pyrrolidone-2 par un groupement méthyle sur le processus de polymérisation (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 189-200 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We tried to evaluate the reason for the very low polymerizability of methyl derivatives of 2-pyrrolidone in the presence of anionic polymerization catalysts. The polymerizability estimated from the influence of the methylated group on the reactivity of the lactam ring (steric, inductive, and thermodynamic factors) does not agree with the experimental results of homopolymerization and copolymerization of 2-pyrrolidone. The substitutional effects on the propagation process were analyzed and an explanation which is based on the slow-down of the molecular growth and the crystallization of the reaction mixture is proposed. Thus, in copolymerizations with a small percentage of substituted lactams, the propagation is very slow with regard to the crystallization, which would allow a quick encagement of the active site by hydrogen bonds, and lead to the spontaneous blocking of polymerization. If this percentage increases, the crystallization cannot take place, and this would, as a consequence. favor all the secondary reactions leading to the formation of bicyclic dimer and oligomers.A “chain multiplication” reaction was found in some cases.
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    Inverse problems in polymer characterization: Direct analysis of polydispersity with photon correlation spectroscopyDedicated to Prof. Dr. Leo De Maeyer on the occasion of his 50th birthday (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 201-209 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method is presented for inverting the Fredholm integral equations of the first kind that arise in many experimental determinations of molecular weight distributions of high polymers. The well known problems of instability and nonuniqueness are minimized by constraining the distribution to be the smoothest nonnegative one that is consistent with the data. Analyses of simulated photon correlation spectroscopy data show that good accuracy can be obtained for unimodal distributions and fair accuracy for certain bimodal ones, provided that systematic errors are kept below the random noise level. The method is completely automatic in that no initial estimate or prior information about the distribution is needed. However, if there happens to be a priori knowledge that the distribution is unimodal or that it is bimodal, constraining the distribution accordingly can further improve the stability and accuracy.
    Additional Material: 4 Ill.
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  • 65
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    Nuclear magnetic resonance in a swollen polycarbonate. Fine structure of 1H NMR line (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 211-218 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several components have been found to be present in the 1H NMR absorption line in polycarbonate (poly(oxy-1,4-phenyleneisopropylidene-1,4-phenyleneoxycarbonyl)), swollen in carbon tetrachloride. The α-component, in the form of a Gaussian function is due to polymer chains present in areas with considerable degree of order. The intermediate β-component can be fitted with good accuracy by the calculated spectrum, by treating the magnetic dipole-dipole interaction as a perturbation of the proton two-spin system. The effect of second neighbours gives a finite width to components of that line. Such a type of fine structure determines with good accuracy the distance between two protons in the ortho-position in the phenyl ring executing some specific motions. Such phenyl rings can be present in tie-molecules of limited mobility performing a conformational reorientation motion. The γ-component is due to the micro-Brownian motion of polymer chains present in the system and also to lower molecular weight fractions of the polymer. This component can be generally described by an appropriate Lorentz function.
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    Melting behavior of syndiotacticity-rich poly(vinyl alcohol)-water gel (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 229-239 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The melting temperatures of a syndiotacticity-rich poly(vinyl alcohol)-water gel were measured for concentrations below 70g.dm-3. In the gel chilled at a temperature below about 15°C the melting point first decreased monotonously then sharply in a jump and again monotonously with decreasing concentration, whereas in the gel chilled above 20°C the melting point decreased monotonously through-out. The change of the shear modulus of a gel chilled at 0°C with the rise of temperature from 0°C to the melting point was also measured. Initially the shear modulus decreased, then increased to a maximum value, and at last decreased towards the melting temperature, whereas a gel chilled at 40°C kept an almost constant value during heating from 40°C up to a high temperature and then decreased with further rise of temperature. The turbidity of dilute solutions chilled at 0°C passed a minimum and maximum with the rise of temperature in accord with the minimum and maximum of the shear modulus. It is thus concluded that in the gel chilled at temperatures below 15°C the junctions grow to some extent with the rise of temperature.
    Additional Material: 5 Ill.
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    Properties of blends of poly(ethylene oxide) samples with different molecular weight: Kinetics of crystallization from melt (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 219-228 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization kinetics of binary blends of samples of poly(ethylene oxide) with different molecular weights, namely 2000, 20 000, and 197000 has been investigated by means of polarized light microscopy in order to establish the dependence of the kinetic parameters upon the composition. The temperature and composition dependence of the growth rates of spherulites in thin films of supercooled melt has been analyzed by means of the theoretical expressions given by Hoffman and Lauritzen. The experimental results indicate that some kinetic and thermodynamic quantities such as the rate of crystallization, the equilibrium melting temperature, the free energy of formation of a nucleus of critical size, and the surface free energy of folding are strongly dependent upon the composition of the blends.
    Additional Material: 8 Ill.
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    Molecular motion in solid polyethylene as studied by 2D wide line NMR spectroscopy (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 241-249 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2D NMR spectra have been measured at variable temperatures between -100°C and +110°C in a sample of melt crystallized deuterated polyethylene (PE). The line shape could be decomposed into a central part originating from deuterons in the amorphous regions and outer parts from crystalline regions of PE. The “NMR crystallinity” determined from this separation was 72% in agreement with the X-ray crystallinity of 74%. Changes of the crystalline NMR line shape were interperted in terms of oscillations around the chain axis, the r.m.s. oscillation amplitude varying from 5° at 40°C to 12° at 110°C. The central part of the NMR line shape indicates the existence of a “narrow” and a “medium” component due to different motional processes in the amorphous regions.
    Additional Material: 7 Ill.
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    Search for critical exponents at the gel-to-sol transition (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 251-253 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
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    Synthese von acrylatmonomeren zum aufbau konstitutionell analoger polyanionen und polykationen (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 255-257 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    URL: http://dx.doi.org/10.1002/macp.1979.021800125
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    Anionic polymerisation of 6-alkyl- and 6,6-dialkylfulvenes (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 259-261 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    The effect of molecular interaction on the intrinsic viscosity (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 263-265 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    URL: http://dx.doi.org/10.1002/macp.1979.021800127
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    Comment on “unperturbed dimensions and critical molecular weight for entanglement of poly(ethylene terephthalate) and poly(ethylene isophthalate)” (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 271-273 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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    A study on long-lived propagating polymer radicals of acrylamide derivatives at room temperature (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 267-269 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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    Hamburg macromolecular symposiumOrganized by Prof. Dr. H. Sinn, Prof. Dr. H. G. Zachmann, and the “Ortsverband Hamburg” of Gesellschaft Deutscher Chemiker. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 271-273 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    Local chain motions of an alternating 1,4-trans-butadiene-propene copolymer in melt studied by high resolution 13C NMRPresented at the “Hamburger Makromolekulares Symposium”, September 14-16, 1978. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 277-280 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    Dielectric dispersion of poly(styrene sulfone) in dioxane solutionPart of a main lecture presented by WHS at “Hamburger Makromolekulares Symposium 1978”. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 281-283 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    Transport equations for concentration fluctuations in macromolecular solutionsPresented at the “Hamburger Makromolekulares Symposium”, September 14-16, 1978. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 285-290 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    Oxidation of tertiary amines with N-chloronylon 66 (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 299-305 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Oxidation of tertiary amines with N-chloronylon 66 (NCN) was investigated in several organic solvents. NCN was found to oxidize N,N-dimethylaniline (DMA) at room temperature to give N-methylaniline with 15-50% yield, depending on the solvents used. Oxidation of N,N-dimethylbenzylamine (DMBA) gave benzaldehyde with 15-30% yield and a small amount of N-methylbenzylamine. A mechanism was discussed. For comparison, N-chlorosuccinimide, a low molecular N-chloro-compound, was also used for oxidation of DMA and DMBA.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800201
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    Attempt of a direct analysis of broad line NMR spectra of polymers combined with results from SAXS and WAXSPresented at the “Hamburger Makromolekulares Symposium”, September 14 - 16, 1978. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 291-298 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800134
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    Functional monomers and polymers, 54.Part 53 of the series: M. Sato, K. Kondo, K. Takemoto, J. Polym. Sci., Polym. Chem. Ed., in contribution. Synthesis of poly-β-alanine from β-alanine 4-acyl-2-nitrophenyl esters (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 307-314 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: A series of active β-alanine 4-acyl-2-nitrophenyl esters with different lengths of alkyl groups was prepared, and their polycondensation was studied in various solvents. The results of the polycondensation of these esters with triethylamine at room temperature show that the conversion and the degree of polycondensation of the resulting poly(β-alanine)s depend on the chain length of the alkyl groups. No polymer was obtained in both protic and dipolar aprotic solvents such as methanol and DMSO, whereas nonpolar solvents such as diethyl ether, carbon tetrachloride, or benzene were found to be suitable for the polycondensation. The effect of a variety of amines on the polycondensation was examined for β-alanine 4-dodecanoyl-2-nitrophenyl ester (4e) in diethyl ether solution.
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    Bestimmung von sequenzlängenverteilungen hydrierter polyalkenylene durch metathese-abbau, 1. Homogen hydriertes polybutadienHerrn Prof. Dr. Phil. Herbert Kölbel zum 70. Geburtstag gewidmet (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 315-323 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: Partially hydrogenated 1,4-polybutadiene is degraded into GC-detectable reaction products after olefin-metathesis with 4-octene in the presence of WCI6/(CH3)4Sn. 1,4-polybutadiene is homogeneously hydrogenated with p-toluenesulfonohydrazide and serves as copolymer with non-hydrogenated and hydrogenated repeating units. Hydrogenated sequences up to an undecade are detectable. The experimental monomer sequence length distribution agrees satisfactorily with the theoretical one calculated under the assumption of an ideal statistical copolymer.
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    Syntheses of polyamides containing theophylline and thymine (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 325-331 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: 2-(1,3-Dimethyl-2,6-dioxo-2,6-dihydropurin-7-yl)methylsuccinic acid (2a) and 2-(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)methylsuccinic acid (2b) were synthesized via the addition reaction of theophylline and thymine, respectively, to dimethyl methylenesuccinate, followed by hydrolysis of the resulting ester. The dicarboxylic acid derivatives 2a and 2b were further converted to their di-p-nitrophenyl esters 3a and 3b, which were allowed to polycondense with diamines such as 1,6-diaminohexane, 1,2-diaminoethane, 3-aminomethylbenzylamine, and piperazine in solutions. The resulting polyamides are white powders with molecular weights in the range of about 2000-6000. The DP of the polyamides varies with the kind of diamines and solvent used. All polyamides are soluble in DMSO and formic acid, the polyamides deriving from esters 3a and 3b and 1,2-diaminoethane and piperazine are also soluble in water.
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    Epoxydation de copolymères triséquencés styrène-isoprene-styrène par l'acide monoperoxyphtaliqueCette étude a été conduite dans le cadre de l'action DGRST du Comité Matériaux Macromoléculaires (Aides n° 75-7-0816 et 76-7-1007). (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 333-338 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Styrene isoprene styrene copolymers (SIS) modified by epoxidizing were investigated in order to obtain adhesive materials. Influences of experimental parameters (concentrations, solvents, compositions of SIS) are shown for epoxidation with monoperoxyphtalic acid at a yield of modification lower than 50%.
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    Effect of a polymeric ligand on the formation of some cobalt(III) and copper(II) complexes with partially quarternized poly(4-vinylpyridine) (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 339-344 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It was found that the formation constants (K) of CuX(QPVP)n- (X = ethylenediaminetetraacetate ion (edta) and N-(2-hydroxyethyl)ethylenediamine-N,N′,N′,-triacetate ion (hedta), QPVP = partially quarternized poly(4-vinylpyridine)) increase sharply with increasing degree of quarternization (Q) of QPVP. In the Cu(edta)2-/QPVP system. K values are 481.mol-1 for Q = 0%, 8701.mol-1, for Q = 25%, and 1,1.103l.mol-1 for Q = 61%, in aqueous methanol (volume ratio 1:1) at μ = 0,1 mol.l-1, pH = 8,0. and T = 25°C. In the system CH3Co(dmg)2H2O/QPVP, K decreases linearly with increasing degree of quarternization of QPVP from K = 1,7.103l.mol-1 for Q = 0% to K = 95l.mol-1 for Q = 61% in aqueous methanol (volume ratio 3:7) at μ = 0,05, pH = 8,0, and T = 25°C. The decrease in K is +scribed to a relatively large decrease in the rate constant of the forward reaction and a small increase in that of the backward reaction.
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    Gpc study of thermo-oxidative degradation of poly(2,6-dimethyl-1,4-phenylene oxide) (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 351-360 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The method of gel permeation chromatography was used to study the structural changes of poly(2,6-dimethyl-1,4-phenylene oxide) in the course of thermooxidative degradation. During the degradation two principal processes occur: random scission and crosslinking. The latter process leads to the formation of insoluble fractions. The reaction rates and activation energies of both processes have been determined. The mechanism of degradation as well as the influence of some additives is discussed on the basis of experimental data.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800208
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    Synthese und halbleitereigenschaften von hemiporphyrazinartigen polymeren mit tetrathiafulvalen-einheitenHerrn Prof. Dr. Heinrich Hellmann zum 65. Geburtstag gewidmet. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 345-350 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hemiporphyrazine type macroheterocycles with 2,2′-bi-1,3-dithiolylidene (tetrathiafulvalene) units in the polymeric chains (3a-e) were obtained by reaction of 2,2′-bi-1,3-dithiolylidenetetracarbonitrile (tetracyanotetrathiafulvalene) (1) with several diamines (2a-e). The black polymers were characterized by elemental analyses and IR spectra. Thermoanalytic measurements showed that decomposition starts without melting at temperatures 〉 300°C. The polymers were found to be polymeric organic semiconductors with activation energies of 0,6-1,4eV and electrical conductivities in the range from 10-14 to 10-10Ω-1.cm-1. In the case of the polymers 3a and 3b it was possible to obtain metal complexes (4a-b) by substituting the two hydrogen atoms inside the macroheterocyclic rings. Depending on the metal atoms the electrical conductivities were enhanced up to two orders of magnitude.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800207
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    Effect of the heteroatom x in the catalytic system ZnR2/o- or m-HXC6H4XH on the copolymerization of carbon dioxide with propylene oxidePart of this work was presented at the 1st European Discussion Meeting on Polymer Science, Strasbourg, February 27 - March 2 1978. (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 361-366 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of new catalytic systems ZnEt2/cocatalyst were prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide was studied. The systems ZnEt2/m-HXC6H4XH (mole ratio 1:1) system (X = NH, S) were chosen to elucidate the influence of the heteroatom on the activity of the catalytic system. The obtained results were discussed in terms of the influence of the basicity of the heteroatom and of its hybridization on the structure and association of the catalyst molecule.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800209
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    Synthesis and exchange reactions of biodegradable drug-binding matrices (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 375-382 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Succinic esters of starch and dextrane (STS and DTS) have been prepared and transformed into the corresponding imidazolides. These are difficult to isolate in a pure state. Without previous isolation, however, they react smoothly with alcohols or amines giving the corresponding polymeric esters or amides. STS benzotriazolide has also been prepared, and isolated in a pure state. It has been found to have the same reactivity towards alcohols and amines than other previously described polymeric benzotriazolides. These results demonstrate that STS or DTS activated amides offer new opportunities to prepare polymer drug adducts with a main backbone degradable to safe metabolites in the body fluids.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800211
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    Effects of some carcinogens on conformation of histonesDedicated to Prof. Dr. W. O. Milligan, Director of Research of The R. A. Welch Foundation (Houston, Texas) on the occasion of his 70. birthday (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 367-373 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Conformational transitions of histones F1 (H1), F2a (H2A), F2b (H2B), and F3 (H3) in the presence of carcinogens 4-nitroquinoline-N-oxide, 13-H-dibenzo[c,j]carbazole, and 7-H-dibenzo[c,q]carbazole were studied by the circular dichroism (CD) probe. The polypeptide main chain conformation of the very lysine rich histone F1 was not affected by these carcinogens, but the tertiary structure was modified slightly by the carbazoles. The secondary structure of histone F2a was significantly modified by the carbazoles which enhanced the helix content, whereas the effect of the 4-nitroquinoline-N-oxide on the backbone conformation was weak. The tertiary structure of F2a was affected by all three carcinogens, whereby the 7-H-dibenzo[c,g]carbazole produced the strongest enhancement of the CD bands assigned to tyrosine and phenylalanine chromophores. Moreover, this carcinogen produced extrinsic Cotton effects in the 300-380nm spectral zone. Similar effects of the carbazoles were observed with histone F2b, although in this case the main chain conformation was changed only slightly. The secondary structure of histone F3 was slightly affected by the carcinogens but the tertiary structure was significantly modified by the carbazoles. The CD bands of F3 which were assigned to the tyrosine and phenylalanine chromophores were most strongly enhanced by the 13-H-dibenzo[c,j]carbazole.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800210
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    Influence of the nature of the blocks on the ordered structures of block copolymers (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 389-396 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structure of AB block copolymers with a polydiene block (polybutadiene or polyisoprene) and another block (polystyrene, poly(α-methylstyrene)), poly(2-vinylnaphthalene), poly(2-vinylpyridine) or poly(4-vinylpyridine) was studied by low angle X-ray diffraction and electron microscopy. The influence of the nature of the non-diene block (styrene, α-methylstyrene, 2-vinylnaphthalene), the nature and the microstructure of the diene block and the isomery of the vinylpyridine block on the parameters of the lamellar structure and the conformation of the macromolecular chains was established.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800213
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    The role of co-operativity in determining the binding behaviour of hetero-charged polyanions with metachromatic dyes (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 383-388 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The binding of acridine orange to carboxyl and sulfate containing polyanions has been investigated by fluorescence spectroscopy. Particular attention has been given to solutions containing both carboxyl and sulfate groups in two different situations, first where both types of site are present attached to the same polymer backbone in a regular repeating structure (heparin), and secondly where individual polymer chains carry exclusively one type of site (hyaluronic acid/K-carrageenan mixtures). Greatly differing behaviour of the binding profiles as the concentrations of components were reduced have been explained in terms of the strong co-operativity of the dye-binding process. The carboxyl and sulfate sites of heparin appear to be equivalent in binding strength, while those of the polycarboxylate polysulfate mixture are no longer equivalent, binding profiles being dominated by the strong binding sulfate group.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800212
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    Polybutadiènes hydroxytéléchéliques, 2Part 1: cf.1. Microstructure et fonctionnalité des polyméres obtenus par voie anionique. Etude par résonance magnétique nucléaire du proton et du carbon 13 (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 397-409 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The examination, by 1H NMR, of anionic hydroxytelechelic polybutadienes in conjunction with accurately measured Mn values allows the simultaneous determination of the number average functionality and the identification of the nature of the chain ends bearing the functional groups. The microstructure of the polymer chains has been studied by 13C NMR. A high proportion of isolated vinyl units has been found only if the percentage of vinyl is less than 70%, whereas the vinyl sequences are atactic. During the functionalization, if lithium is utilized as catalyst, only one molecule of ethylene oxide is added at each end of the polymer chain. With potassium, ethylene oxide polymerizes. Owing to the chain ends, reaction mechanisms of the addition of ethylene oxide onto the living polymer have been proposed.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800214
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    Diffusion rayleigh dans le rouge par les solutions de polymères. Application à quelques problèmes (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 441-453 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper describes how a classical light scattering apparatus (FICA 42000) can be modified in order to allow measurements with red light using a gas laser. This apparatus is calibrated, and experimental results are compared with the theoretical results. The advantages of such measurements are that, when red light is used, one has no fluorescence problems, and the properties of the laser (i.e., collimation, stability and illumination) allow the possibility of simultaneous measurements of both gel permeation chromatography (GPC) and light scattering.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800217
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    Effects of mechanical stress on the reactivity of polymers: Shear degradation of polyacrylamide and dextran (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 411-427 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanical degradation of polyacrylamide and dextran and the acid hydrolysis of dextran at different pH values is investigated in concentrated solutions in high shear laminar flow fields. The kinetics of degradation of polyacrylamide show that the reaction is first order, the rate constants of degradation are proportional to the molecular weight, and the polymer molecules are broken preferentially near the center of the chain. It is found that shear stress is the controlling factor of the degradation process, the rate constants increasing in poor solvents and with decreasing temperatures. The limiting molecular weight is a direct function of the shear stress. For dextran a transition range exists in which shear degradation is favored by hydrogen ions at pH values at which no hydrolysis occurs in the absence of a shearing field.
    Additional Material: 16 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800215
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    Polymerization of α,α-disubstituted β-propiolactones and lactams, 12. Properties and crystalline structure of poly(β-propiolactam)s (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 429-440 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of α,α-disubstituted β-propiolactams (substituted nylon 3 polymers) was prepared from non-optically active lactams. Their thermal characteristics, densities, and x-ray fiber diffraction patterns were recorded. One of the α-substituents was always a methyl group while the other was either CH3, C2H5, n-C3H7, or n-C4H9. The melting point for the dimethyl substituted polymer was 268°C; the others were respectively 76, 74, and 72°C. X-ray fiber diffraction data on all four samples yielded the same fiber repeat of ≈8,4 Å. A minimum energy based conformational analysis for the α,α-dimethyl derivative indicates that two conformations correspond to this repeat, each of which is a 21 helix.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800216
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    Interferenzmikroskopische charakterisierung von faserstrukturen, 32. Mitteilung: cf.7.. Die änderung des radialen verlaufes der physikalischen struktur von polyethylenterephthalat-fasern beim färben mit dispersionsfarbstoffen (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 473-490 
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    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The change of the radial structure during the diffusion of dyestuffs in fibers of poly(ethylene terephthalate), [poly(oxyethyleneoxyterephthaloyl)], is studied with regard to the relationship between the dyestuff diffusion and the structure of high polymers. The fiber structure is described by interferometric measurements, which allow statements about order and orientation as a function of the diffusion path. The experimental results show that C. I. Disperse Red 60 raises the parameters which describe the order and orientation and that C. I. Disperse Blue 139 lowers these structure parameters.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800220
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    Solution properties and flexibility of poly(2-biphenylyl methacrylate) (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 455-464 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dilute solution properties of poly(2-biphenylyl methacrylate), (poly[1-(2-biphenylyloxycarbonyl)-1-methylethylene], POB) were studied by viscosity, sedimentation, light scattering and osmotic pressure in different solvents. The solvent dependence of intrinsic viscosity, [η], Huggins constant, KH, Mark-Houwink exponent, a, and expansion factor, αη, is very weak, although the chemical nature of the solvents is quite different (CHCl3, tetrahydrofuran, benzene, 1,4-dioxane). For poly(4-biphenylyl methacrylate) (poly[1-(4-biphenylyloxycarbonyl)-1-methylethylene], PPB) and other aromatic polymethacrylates the changes of [η], KH, a and aη are very high. The unperturbed dimensions calculated from viscometric and light scattering data by different methods, are in excellent agreement with one another and good agreement with those obtained from sedimentation data. POB has a higher flexibility factor (σ = 2,8) than PPB (σ = 2,7). In our opinion this is due to the fact that the 2-biphenylyl group is closer to the main chain than the 4-biphenylyl group. The very high value of σ explains the weak solvent dependence of [η], KH, a and αη in the case of poly(2-biphenylyl methacrylate).
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800218
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    Crystallization of poly(L-proline) in the course of polymerization (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 465-472 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The heterogeneous polymerization of L-proline N-carboxy anhydride was carried out in acetonitrile and benzene, using butylamine as the initiator. Polyproline I was formed in acetonitrile and polyproline II in benzene in the course of the polymerization. The conversion attained 99% and 66% after 1 week-polymerization in acetonitrile and benzene, resp. Extended chain crystals were obtained by the polymerization in acetonitrile. On the other hand, poly(L-proline) obtained by the polymerization in benzene gave aggregates into which many growing chain ends were occluded. The differences in the crystallization behaviour during the polymerization between the two different liquids may be due to the conformation of the resultant polymers. Polyproline I exhibits a cross-section per chain of 0.709 nm2, whereas polyproline II shows only one of 0,386 nm2. The wider the cross-section per chain the more the growing, active chain ends can react with the monomer, giving rise to a higher conversion. In contrast with the case of crystallization of such α-helical chains as poly(L-alanine) during polymerization, hexagonal lamellar crystals were formed.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/macp.1979.021800219
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    Interferenzmikroskopische charakterisierung von faserstrukturen, 43. Mitteilung: cf.5.. Zusammenhänge zwischen der farbstoffdiffusion und der faserstruktur beim färben von polyethylenterephthalat-fasern mit dispersionsfarbstoffen (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 491-499 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Concentration distributions of dyestuffs C. I. Disperse Red 60 and C. I. Disperse Blue 139 in microtomic cuttings of fibers of poly(ethylene terephthalate), (poly(oxyethyleneoxyterephthaloyl)) are discussed. An interpretation of the results in relation to order and orientation along the fiber radius by interferometric investigations gives informations about the diffusion process. It is shown, that the diffusion of dyestuffs in high polymers depends - in a complicated way - on fiber structure (as a function of the diffusion path), fiber history, and experimental conditions: C. I. Disperse Red 60 shows a lower diffusion rate at higher radial orientations, whereas the diffusion rate of C. I. Disperse Blue 139 does not depend on the radial dependence of these structure parameters.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1979.021800221
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