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J R Fries

Publications and source records attributed to J R Fries.

8 recordsLinked to original sources
PubMed2001

Data registration and selective single-molecule analysis using multi-parameter fluorescence detection.

A general strategy to identify and quantify sample molecules in dilute solution employing a new spectroscopic method for data registration and specific burst analysis denoted as multi-parameter fluorescence detection (MFD) was recently developed. While keeping the experimental advantage of monitoring single molecules diffusing through the microscopic open volume element of a confocal epi-illuminated set-up as in experiments of fluorescence correlation spectroscopy, MFD uses pulsed excitation and time-correlated single-photon counting to simultaneously monitor the evolution of the four-dimensional fluorescence information (intensity, F; lifetime, tau; anisotropy, r; and spectral range, lambda(r)) in real time and allows for exclusion of extraneous events for subsequent analysis. In this review, the versatility of this technique in confocal fluorescence spectroscopy will be presented by identifying freely diffusing single dyes via their characteristic fluorescence properties in homogenous assays, resulting in significantly reduced misclassification probabilities. Major improvements in background suppression are demonstrated by time-gated autocorrelation analysis of fluorescence intensity traces extracted from MFD data. Finally, applications of MFD to real-time conformational dynamics studies of fluorescence labeled oligonucleotides will be presented.

Fluorescent Dyes↗
PubMed1998

Conformational changes of the H+-ATPase from Escherichia coli upon nucleotide binding detected by single molecule fluorescence.

Using a confocal fluorescence microscope with an avalanche photodiode as detector, we studied the fluorescence of the tetramethylrhodamine labeled F1 part of the H+-ATPase from Escherichia coli, EF1, carrying the gammaT106-C mutation [Aggeler, J.A. and Capaldi, R.A. (1992) J. Biol. Chem. 267, 21355-21359] in aqueous solution upon excitation with a mode-locked argon ion laser at 528 nm. The diffusion of the labeled EF1 through the confocal volume gives rise to photon bursts, which were analyzed with fluorescence correlation spectroscopy, resulting in a diffusion coefficient of 3.3 x 10(-7) cm2 s(-1). In the presence of nucleotides the diffusion coefficient increases by about 15%. This effect indicates a change of the shape and/or the volume of the enzyme upon binding of nucleotides, i.e. fluorescence correlation spectroscopy with single EF1 molecules allows the detection of conformational changes.

Amino Acid Substitution↗
PubMed1998

Monitoring conformational dynamics of a single molecule by selective fluorescence spectroscopy.

A recently developed, real-time spectroscopic technique, burst-integrated fluorescence lifetime (BIFL), is shown to be well suited for monitoring the individual molecular conformational dynamics of a single molecule diffusing through the microscopic, open measurement volume (approximately 10 fl) of a confocal epi-illuminated set-up. In a highly diluted aqueous solution of 20-mer oligonucleotide strand of DNA duplex labeled with the environment-sensitive fluorescent dye tetramethylrhodamine (TMR), fluorescence bursts indicating traces of individual molecules are registered and further subjected to selective burst analysis. The two-dimensional BIFL data allow the identification and detection of different temporally resolved conformational states. A complementary autocorrelation analysis was performed on the time-dependent fluctuations in fluorescence lifetime and intensity. The consistent results strongly support the hypothesized three-state model of the conformational dynamics of the TMR-DNA duplex with a polar, a nonpolar, and a quenching environment of TMR.

Kinetics↗
PubMed1984

Hospital work stoppages--the legal basis and the legal response.

Unlike other industries, hospitals are entitled by law to at least ten days' notice of any strike, picketing or concerted refusal to work. By asserting this right, they may plan for continued operation and the continued care of their patients.

Collective Bargaining↗
PubMed1984

Hospital strikes: complying with NLRA notice requirements.

Section 8(g) of the National Labor Relations Act, added in the 1974 amendments to the Act, requires a labor organization to give an employer in the health-care field ten days' notice of an intended strike or picketing. The purpose is to allow the health-care employer time to make arrangements to ensure the continuation of health-care services to critically ill patients. Failure of a union to give this notice constitutes a violation of the Act, and individuals who engaged in the activity may, as a result, lose their status as employees under the Act. In the following article, the authors examine the requirements of section 8(g) and the case law interpreting this statute. They suggest likely future interpretations of this law and make practical suggestions for responding to strikes in the health-care setting.

Labor Unions↗
PubMedDate not supplied

Corporate reorganization in the health care industry: the labor law implications.

Health care mergers, acquisitions, or the creation of new subsidiaries or satellite facilities have significant labor law implications. The National Labor Relations Board may disregard the independent corporate status of two related entities. Such "single employer" status may make a health care organization more susceptible to union organizing, to labor disputes, or to monetary liability for unfair labor practices. The Board may also allow employees at independent facilities of a single employer to organize and bargain as a single unit. Such a multifacility unit may result in employees of small outlying facilities being organized against their wishes. Similarly, the unit accretion theory of the Board allows employees of a newly acquired or newly created small facility to be merged into a larger, existing bargaining unit without an opportunity for an election. Finally, a health institution that acquires or merges with another facility may be obligated to assume and honor an existing union contract. Alternatively, the "successor" may be required to bargain with the union, but not to assume the union's contract. With the proper planning, however, the employer may have no obligation either to bargain or to assume the contract. The successor employer must also be concerned with its liability for unfair labor practices of the seller.

Health Facilities↗