Near-field optical imaging of unstained bacteria: comparison with normal atomic force and far-field optical microscopy in air and aqueous media

Simultaneous near-field scanning optical and atomic force imaging of bacteria is presented. The bacteria imaged in these studies were unstained. The near-field optical images had excellent signal-to-noise and showed excellent contrast even in these unstained specimens. The images obtained were interpreted in terms of the images that have been obtained by transmission electron microscopy and X-ray imaging. The results show that bacterial near-field optical imaging is going to be a very important tool in the arsenal of the bacteriologist both in terms of understanding the fundamental processes in the life cycle of bacteria with and without cytochemical staining and in terms of clinical diagnostic applications.     

Digital Intuition: Applying Common Sense Using Dimensionality Reduction

Understanding the world we live in requires access to a large amount of background knowledge: the commonsense knowledge that most people have and most computer systems don't. Many of the limitations of artificial intelligence today relate to the problem of acquiring and understanding common sense. The Open Mind Common Sense project began to collect common sense from volunteers on the Internet starting in 2000. The collected information is converted to a semantic network called ConceptNet. Reducing the dimensionality of ConceptNet's graph structure gives a matrix representation called AnalogySpace, which reveals large-scale patterns in the data, smoothes over noise, and predicts new knowledge. Extending this work, we have created a method that uses singular value decomposition to aid in the integration of systems or representations. This technique, called blending, can be harnessed to find and exploit correlations between different resources, enabling commonsense reasoning over a broader domain.     

The Story of Collective Action: The Emergence of Ideological Leaders,Collective Action Network Leaders,and Cross-Sector Network Partners in Civil Society

Collective action and community ecology theories frame this study of longitudinal interorganizational networks in Croatia during the country's political transition. As time progresses toward political stability, grass-roots organizing activities shift through participation in new networks. Although engaged cross-sector communication was important in early stages of the transformation, homophilous partnering emerged as the system stabilized. System stability left room for organizations to exit the collective action network but with costs associated with centralized organizing. Over time, organizations embodied roles as ideological leaders, collective action network leaders, and within-sector network partners. We offer a unique contribution to community ecology and collective action theories with a communication-centered framework that emphasizes the nature of communication in interorganizational networks over a 4-year period.     

Multicomponent Bioluminescence Imaging with Naphthylamino Luciferins

Bioluminescent tools have been used for decades to image processes in complex tissues and preclinical models. However, few distinct probes are available to probe multicellular interactions. We and others are addressing this limitation by engineering new luciferases that can selectively process synthetic luciferin analogues. In this work, we explored naphthylamino luciferins as orthogonal bioluminescent probes. Three analogues were prepared using an optimized synthetic route. The luciferins were found to be robust emitters with native luciferase in vitro and in cellulo. We further screened the analogues against libraries of luciferase mutants to identify unique enzyme-substrate pairs. The new probes can be used in conjunction with existing bioluminescent tools for multi-component imaging.     

On the corrosion resistance of the submerged arc welded titanium in concentrated hydrochloric acid 8 N

The corrosion behaviour of the submerged arc welded T-35 in concentrated 8 N HCl has been investigated. The weld metal is characterized by a martensite type structure, a hardness superior by 60 HV and an oxygen content about two and a half times higher than the base metal. In order to underline the part played by oxygen and structural transformations intervening during the welding operation, an analysis of the anodic current-potential curves by a reaction model involving four determining steps has been carried out. It has been shown that the two reaction rates which determine the passivation and the passivity of the metal depend on the oxygen content as well as the metallurgical structure. In the active dissolution range, whereas one of the two determining rates depends on the oxygen content, the other one is controlled by the metallurgical structure of the metal.     

Carboxypeptidase B-like activity and C3 in cystic fibrosis

Assays of carboxypeptidase B-like activity and C3 in serum from patients with cystic fibrosis and appropriate control subjects failed to demonstrate a deficiency of carboxypeptidase B-like activity or a consistent increase in C3, as was suggested by Conover and associates. Differences between men and women with cystic fibrosis were apparent, in that women with cystic fibrosis had higher concentrations of both serum carboxypeptidase B-like activity and C3 than either men with cystic fibrosis or control subjects.