Twenty children with juvenile recurrent parotitis, between 3 months and 16 years of age at onset, were followed up over a period of 7 to 22 years. Radiologic, histopathologic, cytologic, immunologic, and bacteriologic studies were performed to investigate the cause of sialectasis, commonly found in juvenile recurrent parotitis, and the pathogenesis of the disease. It was considered that a combination of a congenital malformation of portions of the salivary ducts and infections ascending from the mouth following dehydration of the children are contributory to the pathogenesis of the disease. The results of the investigations into the cause of the disease appear to exclude an auto-immunologic response or an allergic condition, an immature immune response, mumps, a sensitivity to upper respiratory tract infection, and familial factors.

SUM M . 4 R Y :The solvent dependence of the intrinsic viscosity of hydroxyethyl cellulose has been investigated. Light scattering and viscosity measurements were made in the solvents water and cadoxen. The results are interpreted in the light of the FLORY theory. I n water, hydroxyethyl cellulose behaves as an inflexible, highly extended chain, while in cadoxen it exhibits properties typical of a flexible polymer.The temperature dependence of [r;] in water solutions was examined by light scattering measurements in the range 0-60°C. The negative temperature dependence of [q] is found to be approximated by that of the unperturbed coil extension, ($/'i). This reflects the increasing flexibility of the molecule with increasing temperature.Light scattering measurements were made in 0.5 M NaC1,0.5 M NaOH, and 0.5 M HCI. I n cadoxen and 0.5 M NaOH the molecule exhibits smaller coil dimensions and a greater flexibility than in neutral or acid solutions. It is suggested that in cadoxen and 0.5 M NaOH the solvent mechanism is one involving strong interactions with the hydroxyl groups of the monomer unit, In neutral and acid solutions the greater inflexibility and larger coil dimensions are thought to be caused by an extensive packing of solvent molecules around the chain so as to restrict the rotations of the monomer units.From sedimentation data of hydroxyethyl cellulose in water, molecular parameters are calculated using a recent theory of HEARST and STOCKMAYER. ZUSAMMENFASSUNG:Er wurde die Abhangigkeit der Viskosit%tszahl [q] von Hydroxyiithylcellulose vom Losungsmittel untersucht. Die Resultate von Lichtstreuungs-und Viskositatsmessungen wurden gemaI3 der Theorie von FLORY gedeutet.Gelost in Wasser, verhiilt sich Hydroxyathylcellulose wie steife, stark gestreckte Fadenmolekiile, wahrend sie in Cadoxen mehr die Eigenschaften von flexiblen Makromolekiilen zeigt.Die Temperaturabhangigkeit der Viskositatszahl i m Bereich von 0-60°C in w8iDriger Losung wurde durch Lichtstreuungsmessungen untersucht. Die Abnahme der Viskositiitszahl [q] mit steigender Temperatur wurde sehr ahnlich der der ungestorten Knkuelstrekkung @$z) gefunden. Dies spiegelt die zunehmende Flexibilitiit der Molekiile mit steigender Temperatur wider.Lichtstreuungsmessungen wurden in 0,5 m Natriumchlorid-, 0,5 m Natriumhydroxydund 0,5 m Salzsiiurelosungen ausgefiihrt. In Cadoxen und in 0,s m Natriumhydroxydlosung zeigen die Molekiile kleinere Kniiuelabmessungen und grolere Flexibilitat als in neutralen und in sauren Liisungen. Der Liisungsmechanismus in Cadoxen und in 0,5 rn NaOH wird durch starke Wechselwirkung zwischen dem Losungsmittel und den Hydroxylgruppen der Monomereinheiten erkliirt. Die grodere Steifheit und die groderen Knaueldimensionen in neutralen und in sauren Liisungsmitteln kann man sich durch merkliche Solvatisierung der Fadenmolekiile verursacht denken, die die Rotation der Monomereinheiten hindert.Mit Hilfe von Sedimentationsmessungen der Hydroxyathylcellulose in Wasser werden die Molekularparameter nach einer neueren Theorie von HEARST...

Triethylenediamine-cadtviuni h: droxide (cadoxen) has been found to be an excellent solvent for several cellulose derivatives, making possible comparative studies of cellulose and cellulose derivatives. This paper describes an investigation of the system sodium carboxymethyl cellulosecadoxen, using viscosity, osmometry and light scattering measurements.Using three series of samples in the substitution range 0.2 to 1, the effect of the degree of substitution has been studied with regard to its influence on the molecular configuration and dilute solution properties.It is found that sodium carboxymethyl cellulose in cadoxen possesses a configuration independent of the degree of substitution. Furthermore, the configuration is similar to that of cellulose in this solvent. As indicated by the low values of extension parameters such as the effective bond length, b, the KUIIN-KUHN equivalent chain segment length, Am, and the ratio of the unperturbed dimension to the dimension assuming free rotation of the chain units, (Ri/Ri)lI2, it is concluded that sodium carboxymethyl cellulose in cadoxen displays characteristics of a randomly coiled polymer in a good solvent. -_ ZUSAMMENFASSUNG:Triathylendiamin-Cadmiumhydroxyd (Cadoxen) ist ein hervorragendes Losungsmittel sowohl fur Cellulose als auch fur einige ihrer Derivate. Dadurch werden vergleichende Studien dieser Stoffe moglich.Die vorliegende Arbeit beschreibt eine Untersuchung des Systems Natrium-Carboxymethylcellulose durch Messungen von Viskositat, Osmose und Lichtstreuung.An drei Serien von Proben wurde die Abhangigkeit der Konfiguration*) der Makromolekiile sowie der Eigenschaften verdiinnter Losungen vom Substitutionsgrad im Bereich 0,2 bis 1 studiert.Die Konfiguration von Natrium-Carboxymethylcellulose in Cadoxen wurde vom Substitntionsgrad unabhangig und ahnlich der von Cellulose im genannten Losungsmittel gefunden.Eine Betrachtung der gefundenen niedrigen Werte fur die Streckungsparameter, wie die effektive Bindungslange b, die Lange Am des statistischen Fadenelementes nach KURN-KUHN sowie das Verhaltnis (R$/Ri)1'2 der Dimensionen des ungestorten Molekiils zu den Dimensionen unter der Annahme freier Rotation der Fadenelemente, fiihrt zu dem SchluB, daB Natrium-Carboxymethylcellulose in Cadoxen den Charakter eines statistischen Knauelmolekuls in einem guten Losungsmittel zeigt.--* ) I m Sinne der Formenmannigfaltigkeit.

In what ways might informational techniques and information technology alter the infrastructure of society? The approach employed in this paper involves a number of fundamental, almost historically determined, conditions for the emergence of an increasingly societal infrastructure. This discussion is then related to analyses of the significance of information and communication technologies (ICT) in terms of ubiquities, agglomerations and clusters. Are there grounds for assuming that these trends are having an impact on the systems of towns and cities of differing sizes and at varying distances? In conclusion, the discussion turns to the issue of whether developments in informational techniques over the past 20 years are leading towards what has been referred to as a digital division of labour and, by extension, also towards a ‘digital (societal) infrastructure’.

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