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Multilevel and analogue memory cells have the capability of storing considerably more than one bit of information per cell. The number of levels the memory cells can store is limited by noise and bit error probability. The authors propose using error correction coding and digital modulation techniques used in communication systems to increase the storage capacity of multilevel and analogue memory cells. They evaluate these techniques and find that compared to the methods that do not use coded modulation techniques, typically, one extra bit per cell (i.e. effectively doubling the number of levels per cell) in storage capacity can be achieved. The techniques can also be applied to improve readout bit-error probability and provide unequal error protection for the bits to be stored. The latter technique is important for the efficient storage of digitised multimedia signals such as speech, audio, image and video signals. One- and two-dimensional coded modulation schemes as well as uncoded multilevel digital modulation schemes are presented in detail. Complexity and speed issues are also considered.

Platelet-derived growth factor-stimulated actin rearrangement and edge ruffle formation have previously been shown to be dependent on activation of phosphatidylinositol 3'-kinase, the activity of which also is important for directed migration of cells. This lipid kinase binds to phosphorylated tyrosine residues Y740 and Y751 in the kinase insert of the human platelet-derived growth factor ss-receptor. We examined the role of two other tyrosine residues in the kinase insert of this receptor, Y775 and Y778, for ligand-induced actin rearrangement. Both were shown to be phosphorylation sites; Y775 was only marginally phosphorylated in cells expressing the wild-type ss-receptor, whereas Y778 was phosphorylated at higher stoichiometry. Mutant receptors Y775F, Y778F and Y775/778F were active kinases and mediated proliferative responses when expressed in porcine aortic endothelial cells. Fluorescence staining of actin in platelet-derived growth factor-stimulated PAE cells revealed that Y778 is involved in regulation of the actin cytoskeleton since the cells contained, apart from edge ruffles and circular ruffles, a novel type of giant ruffle on the dorsal side of the cell, which consisted of irregular multilayered actin structures. Mutation at Y778 had no effect on activation of phosphatidylinositol 3'-kinase, nor on the GTPase activating protein of Ras and phospholipase C(gamma), and the extent of directed migration towards platelet-derived growth factor of these cells was not changed. We conclude that actin rearrangement is regulated in part by Y778 in the platelet-derived growth factor ss-receptor, potentially through binding of a novel signaling molecule to this site.

Physical activity plays a role in the maintenance of the skeleton but the mechanical, metabolic and hormonal mechanisms involved are largely unknown. The influnence of acute endurance and strength exercise on circulating levels of calcitonin, parathyroid hormone (PTH), PTH‐related peptide (PTHrP), osteocalcin, carboxyterminal cross‐linked telopeptide of type I collagen (ICTP) and ionized calcium (Ca2+) was therefore evaluated. Eight healthy young males performed three exercise bouts on separate accasions: endurance exercise i.e. cycling on a cycle ergometer for 45 mim at 55% of Vo2max(E55%) and 15 min at 85% of Vo2max(E 85%) and strength exercise at 85% of three repetitions maximum using a legpress device (STR). Control experiments included the same subjects with the same time schedule but without exercise. Blood samples were taken before, immediately after exercise and during the recovery period. Hormones and bone markers were measured by use of various immunoassays. There was no obvious influence on calcitonin and PTHrP levels, whereas PTH was increased after strength exercise. ICTP and osteocalcin levels correlated positively at all times and showed regular variations. In comparison with the controls, ICTP levels showed a more pronounced decrease following physical activity whereas osteocalcin followed the same pattern as the controls except for after prolonged endurance exercise when a decrease was abolished. In conclusion, an increase in PTH after strength exercise and a pronounced decrease in ICTP after all exercise together with a relative increase in osteocalcin after prolonged endurance exercise might reflect some mechanisms involved in the positive effect of physical activity on bone mass.

Without Abstract:

Platelet-derived growth factor-stimulated actin rearrangement and edge ruffle formation have previously been shown to be dependent on activation of phosphatidylinositol 3′-kinase, the activity of which also is important for directed migration of cells. This lipid kinase binds to phosphorylated tyrosine residues Y740 and Y751 in the kinase insert of the human platelet-derived growth factor ss-receptor. We examined the role of two other tyrosine residues in the kinase insert of this receptor, Y775 and Y778, for ligand-induced actin rearrangement. Both were shown to be phosphorylation sites; Y775 was only marginally phosphorylated in cells expressing the wild-type ss-receptor, whereas Y778 was phosphorylated at higher stoichiometry. Mutant receptors Y775F, Y778F and Y775/778F were active kinases and mediated proliferative responses when expressed in porcine aortic endothelial cells. Fluorescence staining of actin in platelet-derived growth factor-stimulated PAE cells revealed that Y778 is involved in regulation of the actin cytoskeleton since the cells contained, apart from edge ruffles and circular ruffles, a novel type of giant ruffle on the dorsal side of the cell, which consisted of irregular multilayered actin structures. Mutation at Y778 had no effect on activation of phosphatidylinositol 3′-kinase, nor on the GTPase activating protein of Ras and phospholipase C(gamma), and the extent of directed migration towards platelet-derived growth factor of these cells was not changed. We conclude that actin rearrangement is regulated in part by Y778 in the platelet-derived growth factor ss-receptor, potentially through binding of a novel signaling molecule to this site.

Immunoblot experiments and reverse-phase h.p.l.c. were used to study the levels of glutathione transferase subunits 1, 2, 3, 4, 6, 7 and 8 in the liver and adrenal of intact and hypophysectomized male and female Sprague-Dawley rats. A sexual dimorphism in the levels of several of these isoenzymes and in their responses to hypophysectomy was demonstrated. In the liver of sham-operated females and males there are differences in glutathione transferase activities and isoenzyme pattern. H.p.l.c. analysis showed higher levels of subunits 1, 3 and 4 in male rats compared with females. In contrast with the pronounced sex differences in sham-operated rats, the isoenzyme patterns of hypophysectomized males and females were very similar. In the adrenal glands, however, a sexual dimorphism became apparent only after hypophysectomy, when the level of subunit 4 was increased 14-fold in the female, whereas the corresponding increase in the male rat was only 2.7-fold. The hepatic pattern of glutathione transferase subunits could be altered by continuous infusion of growth hormone to both sham-operated and hypophysectomized rats of both sexes. This treatment feminized the isoenzyme pattern in sham-operated males and a similar effect was obtained upon treating hypophysectomized rats with thyroxine, cortisone acetate and a continuous infusion of growth hormone.

Zusammenfassung: Im experimentellen Krampfanfall (bei subcutaner Zufuhr von Campher und von Cocain, bei Wirkung von Strychnin auf die motorische Hirnrinde und bei faradischer Rindenreizung) ist das Verhalten des Muskels im Klonus ein verschiedenes. Es kommen sowohl Kloni vor, welche Einzelzuckungen sind, als auch Kloni, in welchen der Muskel eine Reihe kurzer Tetani ausf�hrt. Ferner treten die Kloni auch in Form von Summierungen von nur ganz wenigen Einzelzuckungen (2 und mehr) auf. Keine dieser Formen ist f�r eine bestimmte Ausl�sungsart des Krampfanfalls charakteristisch.

A method is given for analysing constant-envelope signalling schemes with partial-response baseband pulses. We consider coherent phase-tree demodulation for the Gaussian channel. The results show that very good spectral properties can be obtained for systems with error probabilities equal to or better than for binary phase-shift keying.

Asymptotically optimal soft decision decoding algorithms for d = 3 and d = 4 Hamming codes are given and analysed. Only error sequences with probability exponent larger than that of maximum-likelihood decoding are corrected. Upper bounds on the block error probability for the Gaussian channel are given.

To reduce the heat loading in the Tilden Mine kilns caused by the burning of coal, which results in a rapid and significant build-up on the kiln lining, internal carbon was added to the green ball prior to balling. Intensive laboratory testing led to three short-term full-scale plant tests that were successfully conducted. Appropriate environmental permits were obtained to allow Tilden to use internal carbon on a continuous basis. Findings concerning carbon addition rates, reductions in coal use, build-up reductions, fired pellet quality and environmental issues are discussed.

A distance measure is derived for simplified coherent receivers for general digital modulation schemes. This measure gives the asymptotic error probability performance on the additive white Gaussian noise channel. It is applied to some simple examples considering phase modulated signals.