A support vectors classifier approach to predicting the risk of progression of adolescent idiopathic scoliosis.

A support vector classifier (SVC) approach was employed in predicting the risk of progression of adolescent idiopathic scoliosis (AIS), a condition that causes visible trunk asymmetries. As the aetiology of AIS is unknown, its risk of progression can only be predicted from measured indicators. Previous studies suggest that individual indicators of AIS do not reliably predict its risk of progression. Complex indicators with better predictive values have been developed but are unsuitable for clinical use as obtaining their values is often onerous, involving much skill and repeated measurements taken over time. Based on the hypothesis that combining common indicators of AIS using an SVC approach would produce better prediction results more quickly, we conducted a study using three datasets comprising a total of 44 moderate AIS patients (30 observed, 14 treated with brace). Of the 44 patients, 13 progressed less than 5 degrees and 31 progressed more than 5 degrees. One dataset comprised all the patients. A second dataset comprised all the observed patients and a third comprised all the brace-treated patients. Twenty-one radiographic and clinical indicators were obtained for each patient. The result of testing on the three datasets showed that the system achieved 100% accuracy in training and 65%-80% accuracy in testing. It outperformed a "statistically equivalent" logistic regression model and a stepwise linear regression model on the said datasets. It took less than 20 min per patient to measure the indicators, input their values into the system, and produce the needed results, making the system viable for use in a clinical environment.     

Molecular self-assembly of "nanowires"and "nanospools" using active transport

Mastering supramolecular self-assembly to a similar degree as nature has achieved on a subcellular scale is critical for the efficient fabrication of complex nanoscopic and mesoscopic structures. We demonstrate that active, molecular-scale transport powered by biomolecular motors can be utilized to drive the self-assembly of mesoscopic structures that would not form in the absence of active transport. In the presented example, functionalized microtubules transported by surface-immobilized kinesin motors cross-link via biotin/streptavidin bonds and form extended linear and circular mesoscopic structures, which move in the presence of ATP. The self-assembled structures are oriented, exhibit large internal strains, and are metastable while the biomolecular motors are active. The integration of molecular motors into the self-assembly process overcomes the trade-off between stability and complexity in thermally activated molecular self-assembly.     

Towards a Formal and Implemented Model of Argumentation Schemes in Agent Communication

Argumentation schemes are patterns of non-deductive reasoning that have been the focus of extended study in argumentation theory. They have also been identified in computational domains including multi-agent systems as holding the potential for significant improvements in reasoning and communication abilities. By focusing on models of natural language argumentation schemes, and then building formal systems from them, direct implementation in multi-agent environments becomes a possibility. The formal, representational and implementational details are presented here, along with results that demonstrate not only advantages of flexibility, scope, and knowledge sharing, but also of computational efficiency.     

The CEA test and other immunological tests as disease course controls in gastrointestinal adenocarcinoma

161 patients with adenocarcinoma of the gastrointestinal tract were studied to determine the value of the CEA test and a battery of non-specific immunological tests during the course of the disease. The ability of these tests to detect a tumor recurrence in radically operated patients was evaluated. A false negative preoperative CEA value was found in 40% of the patients with gastric carcinoma and 32% with colorectal carcinoma. Patients with a negative preoperative CEA value, and those with only slightly elevated values, had a distinctly better prognosis regarding initial operability and tendency to postoperative recurrence than patients with primarily markedly elevated values. With few exceptions, the development of distant metastases was detected earlier and more easily with the CEA test than by the usual routine follow-up methods. However, in the event of isolated local recurrence the CEA test was positive in only 1 of 5 patients. This reflects the direct correlation between tumor size and CEA elevation. The CEA test is a valuable supplement in the follow-up of patients with gastrointestinal carcinoma.     

A gateway development system

There are an increasing number of local area networks being developed and built for use in a wide range of environments. The underlying communication architecture in the majority of cases is either a broadcasting or ring system. This paper describes a gateway development system which is specifically designed to deal with the interconnection of broadcast and ring systems. The gateway makes use of recently developed microprocessor chips to handle the different requirements of the two networks being connected. In particular, the gateway will be used to link an Ethernet-like system and a Cambridge Ring.     

Das Ergebnis der Wassergehaltsbestimmung von Butter in Abh?ngigkeit von der Arbeitsweise mit und ohne Verteilungsmitteln

Zusammenfassung Die Frage, ob Natriumchlorid allgemein — und welcher Reinheitsgrad der geprüften 5 Salzsorten im besonderen — geeignet sei, bei der gravimetrischen Butterwasserbestimmung (Trockenschrankmethode) das üblicherweise verwendete Ver teilungsmittel Seesand mit Vorteil zu ersetzen, bzw. ob unter Umständen bei dieser Arbeitsweise — vergleichsweise zur Schnellmethode — ebenfalls auf ein Verteilungsmittel verzichtet werden kann, wurde durch statistisch ausgewertete Vergleichsuntersuchungen beantwortet.Es ergab sich, daß die geprüften Salze: Natriumehlorid zur Analyse a) — reinst, getrocknet, fein gepulvert b) — reinst, getrocknet c) — reinst, kristallisiert DAB. 6. d) sowohl im Hinblick auf die Genauigkeit der Arbeitsweise, als auch in bezug auf die statistisch gesicherte Gleichartigkeit der Ergebnisse, ferner hinsichtlich der Troeknungszeit dem Verteilungsmittel Seesandgleichwertig sind. Diese Feststellung trifft bei Verwendung eines Kochsalzes mit nicht definiertem Reinheitsgrad [Salz e)] nurmehr beschränkt zu: Trotz ausreichender Genauigkeit ergibt sich bei dessen Verwendung ein niedrigerer Wassergehalt der Butter als mit Seesand, eine Unterschiedlichkeit, die statistisch gesichert ist. Auch eine vergleichsweise fast doppelt so lange Trocknungsdauer spricht gegen dessen Verwendung.Welchem von den geeigneten Salzen der Vorzug einzuräumen ist, kann nur bei gegenseitiger Abwägung verschiedener Faktoren entschieden werden:Nicht erforderlich ist es, sich einseitig auf die Verwendung von Natriumchlorid mit dem höchsten Reinheitsgrad; NaCl pro anal., festzulegen, vielmehr scheint in bezug auf Genauigkeit, Gleichartigkeit, Troeknungszeitund Preis das Natriumchlorid reinst, getrocknet, fein gepulvert b) das Salz derWahl zu sein.Bei der gravimetrischen Methode (Trocknung in einstündigen Intervallen bei 103–105°C im Trockenschrank bis zur Gewichtskonstanz) ist der Arbeitsweise mit Verteilungsmitteln gegenüber der Arbeitsweise ohne Verteilungsmitteln in bezug auf Genauigkeit und Zeitaufwand der Vorzug zu geben.Die Notwendigkeit eines Verreibens der Butter mit dem Verteilungsmittel besteht bei der Wasserbestimmungnicht, vielmehr erwies sich — vergleichsweise dazu — die Arbeitsweise des Nichtverreibens im Hinblick auf die Genauigkeit und Zeitdauer der Bestimmunggleichwertig, arbeitstechnisch gesehen aber überlegen.     

Piecewise linear optimization: Duality and numerical results

The dual of an optimization problem with piecewise linear, convex, and continous objective function and linear restrictions is investigated. It is shown that the dual problem is of the same type as the primal and can be solved by the same methods as were proposed in a previous work of the author. Experiences arising from the application of different variants of these methods to solve a number of examples, where the primal as well as the dual version was employed, are reported.     

Inhibition of GABA metabolism in rat brain slices by halothane

Based on studies with rat cerebral cortex slices, it was previously hypothesized that halothane anesthesia may result from increased GABA (gamma-aminobutyric acid) content in the synapses. Since GABA is an inhibitory neurotransmitter, such increases may cause a reduction in synaptic activity. The increase in GABA content could arise from several possible causes which are examined in this study using rat cerebral cortex slices as a model. The effects of halothane on uptake, release, and catabolism of GABA were determined. Uptake was studied by the amounts of radioactive GABA accumulated by the slices, and release studied by that discharged into the medium from slices preloaded with radioactive GABA. Catabolism was assessed by preloading the slices with radioactive GABA and then followed by measuring the amount of radioactivity found in unmetabolized GABA or in pooled GABA metabolites. Since CO2 was established as a major metabolite, it was subsequently used alone to measure the inhibition of GABA catabolism in the presence of varying amounts of halothane. Halothane (3 per cent) did not affect the high-affinity uptake or the release of GABA but did inhibit the catabolism of GABA. Using 14CO2 production as an index of catabolism, the inhibition of GABA catabolism by halothane was dose-related (8.79 per cent inhibition/per cent halothane). Such results support the hypothesis that halothane anesthesia may result at least in part from an inhibition of GABA catabolism which, in turn, causes increased GABA level in the synapse with resultant synaptic inhibition.