One major challenge in noninvasive mapping of various molecular targets is their inherently low in vivo concentration coupled with the insensitivity of imaging modalities, such as the widely used ...magnetic resonance imaging (MRI). Development of agents with high sensitivity and specificity is of paramount importance for structural and functional noninvasive imaging. The design, synthesis, and physiochemical characterization of two gadolinium‐based contrast agents (CAs) for MRI, the sensitivity of which was optimized by exploiting the well‐established biotin–avidin amplification strategies, are reported. The relaxivity of these agents showed a large increase if bound to avidin; specifically, the first compound showed an approximately 1000 % increase in transverse proton relaxivity (r2p), whereas the second compound had an approximately 250 % r2p increase. The increase in r2p was magnetic field independent in the range of 1.5–16.4 T whereas the longitudinal proton relaxivity (r1p) showed strong field dependence. The CAs were further characterized by measuring luminescence lifetimes and emission spectral changes upon addition of avidin to their Eu3+ analogues. The difference in relaxation rate behavior of both complexes was explained on the basis of hydration number modulation and the “global/internal motion concept”. The association constant of these CAs with avidin was found to be in the range of approximately 1015 M−1, which shows that the coupling of biotin to Gd‐DO3A did not affect its affinity for binding to avidin (DO3A=1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid).
High relaxivity contrast agents for targeted MRI: Two biotinylated contrast agents (CAs), Gd.L1–2, have been synthesized and characterized for magnetic resonance imaging (see figure). On binding to avidin, the transverse proton relaxivity (r2p) of Gd.L1 undergoes a 906 % increase compared with 225 % for Gd.L2. The longitudinal proton relaxivity (r1p) shows strong field dependence. Gd.L1–avidin allows access of two H2O molecules to Gd whereas Gd.L2–avidin allows one.
Contrast agents for magnetic resonance imaging (MRI) that exhibit sensitivity toward specific ions or molecules represent a challenging but attractive direction of research. Here a Gd3+ complex ...linked to an aminobis(methylenephosphonate) group for chelating Ca2+ was synthesized and investigated. The longitudinal relaxivity (r 1) of this complex decreases during the relaxometric titration with Ca2+ from 5.76 to 3.57 mM−1 s−1 upon saturation. The r 1 is modulated by changes in the hydration number, which was confirmed by determination of the luminescence emission lifetimes of the analogous Eu3+ complex. The initial in vivo characterization of this responsive contrast agent was performed by means of electrophysiology and MRI experiments. The investigated complex is fully biocompatible, having no observable effect on neuronal function after administration into the brain ventricles or parenchyma. Distribution studies demonstrated that the diffusivity of this agent is significantly lower compared with that of gadolinium−diethylenetriaminepentaacetic acid (Gd−DTPA).
Intellectual capital (IC) and social capital (SC), as forms of intangible value in organizations, are crucial assets in today's volatile business environment. Efforts to retain and develop these ...intangibles are becoming more deliberate and disciplined. However, organizations fail to recognize the relationship between organizational distress and the loss and/or reduction of intangible value. The loss of intangible value may potentially impact an organization with equal or greater damage than the loss of more tangible value. IC and SC generate many outcomes beneficial to the individual and the organization. These benefits are reduced when stress of employees becomes excessive and damaging. The relationship between the health of an organization and the degree of impact of distress serves as a lingering threat to organizational financial resources. Managers must build upon the growing knowledge from research and practice to help organizations account for the costs of organizational distress, translate the importance of intangible value into tangible terms, and garner support for developing IC and SC to obtain business objectives. Deliberate and disciplined effort to build collaborative capital can facilitate the growth of IC and SC which minimize the damage of organizational distress.
To investigate the connectivity of brain networks noninvasively and dynamically, we have developed a new strategy to functionalize neuronal tracers and designed a biocompatible probe that can be ...visualized in vivo using magnetic resonance imaging (MRI). Furthermore, the multimodal design used allows combined ex vivo studies with microscopic spatial resolution by conventional histochemical techniques. We present data on the functionalization of biocytin, a well-known neuronal tract tracer, and demonstrate the validity of the approach by showing brain networks of cortical connectivity in live rats under MRI, together with the corresponding microscopic details, such as fibers and neuronal morphology under light microscopy. We further demonstrate that the developed molecule is the first MRI-visible probe to preferentially trace retrograde connections. Our study offers a new platform for the development of multimodal molecular imaging tools of broad interest in neuroscience, that capture in vivo the dynamics of large scale neural networks together with their microscopic characteristics, thereby spanning several organizational levels.
A measure of the frequency of employees' use of ingratiatory behavior at work was tested with a sample of employees (
N
= 716) working in a wide variety of organizations and jobs. Pilot testing ...reduced a 65-item pool to a 24-item instrument with four factors: Other Enhancement, Opinion Conformity, Self-Presentation, and Favor-Rendering. Internal consistency reliability was .92; test-retest reliability over one month was .73. Evidence for content, convergent, and discriminant validity was substantial. The Measure of Ingratiatory Behaviors in Organizational Settings (MIBOS) should enable researchers to focus on the empirical study of ingratiatory behaviors in organizations.
Global competition and rapid changes in technology demand more innovation in organizations. Such an increase in innovation depends on developing the capabilities of employees and providing them with ...knowledge management support that accelerates learning and discovery. Leading companies have been creating work environments that emphasize learning and knowledge management since the turn of the century. This chapter presents profiles of practices in five such companies and draws conclusions that result in a model that ties human resource development (HRD) practices to knowledge management practices as a guide for other organizations.
One major challenge in noninvasive mapping of various molecular targets is their inherently low in vivo concentration coupled with the insensitivity of imaging modalities, such as the widely used ...magnetic resonance imaging (MRI). Development of agents with high sensitivity and specificity is of paramount importance for structural and functional noninvasive imaging. The design, synthesis, and physiochemical characterization of two gadolinium-based contrast agents (CAs) for MRI, the sensitivity of which was optimized by exploiting the well-established biotin-avidin amplification strategies, are reported. The relaxivity of these agents showed a large increase if bound to avidin; specifically, the first compound showed an approximately 1000% increase in transverse proton relaxivity (r^sub 2p^), whereas the second compound had an approximately 250% r^sub 2p^ increase. The increase in r^sub 2p^ was magnetic field independent in the range of 1.5-16.4 T whereas the longitudinal proton relaxivity (r^sub 1p^) showed strong field dependence. The CAs were further characterized by measuring luminescence lifetimes and emission spectral changes upon addition of avidin to their Eu^sup 3+^ analogues. The difference in relaxation rate behavior of both complexes was explained on the basis of hydration number modulation and the "global/internal motion concept". The association constant of these CAs with avidin was found to be in the range of approximately 10^sup 15^M^sup -1^, which shows that the coupling of biotin to GD-DO3A did not affect its affinity for binding to avidin (DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid). PUBLICATION ABSTRACT
Self-managing work groups are a form of work design in which employees take responsibility for the group's tasks and have discretion over decisions which impact group performance. To explore the ...impact of age and work teams on job attitudes, data from 477 employees suggested that self-managed work group members differed from traditional job holders regarding perceived general job satisfaction, perceived control by supervisors, as well as a number of specific dimensions of the work environment. Moreover, while there was evidence of an age effect on attitudes toward supervisory control, there was no joint effect of age by work design on job attitudes, i.e., one's perceived general job satisfaction. Older employees who were members of self-managed work groups were however, more impacted by this form of work design in reporting more positive perceptions of their access to information essential to the performance of their work. These findings suggest that an "older" work force should not be considered a barrier to implementing a work teams approach to job design.
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