The enigmatic fascia: eosinophilic fasciitis.

This case report highlights the potentially underrecognized subtype of unilateral eosinophilic fasciitis (EF) in a 28 year old man. With fewer than 300 reported encounters to date, EF is a rare disease that eludes clinicians by presenting as a scleroderma like syndrome. As EF remains a clinical diagnosis, biopsy results may be nonspecific, and the disease can easily be misdiagnosed (or missed entirely) if a full thickness biopsy is not reviewed by a dermatopathologist.

In memory of Thomas Turpin Bannister (1930-2018).

Tom Bannister (1930-2018) was an extraordinary person and a remarkably productive scientist. He began his career studying the basics of photochemistry, biophysics, and biology of photosynthetic pigments and later moved on to primary production of algae. His publications on modeling of primary production rates in aquatic systems are among the most widely cited in the field of phytoplankton ecology.

Förster's resonance excitation transfer theory: not just a formula.

After 65 years of increasing scrutiny and application, Theodor Förster's treatment of resonance excitation transfer is widely quoted and has acquired the acronym FRET, in which "F" originally and rather curiously stood for "fluorescence." In this brief and mostly qualitative survey, we review some of its history, mention its important limitations, and relate some personal encounters with Förster.

Using delta 15N values in algal tissue to map locations and potential sources of anthropogenic nutrient inputs on the island of Maui, Hawai'i, USA.

Macroalgal blooms of Hypnea musciformis and Ulvafasciata in coastal waters of Maui only occur in areas of substantial anthropogenic nutrient input, sources of which include wastewater effluent via injection wells, leaking cesspools and agricultural fertilizers. Algal delta(15)N signatures were used to map anthropogenic nitrogen through coastal surveys (island-wide and fine-scale) and algal deployments along nearshore and offshore gradients. Algal delta(15)N values of 9.

Entropy production and the Second Law in photosynthesis.

An assertion that the primary photochemistry of photosynthesis can violate the Second Law of thermodynamics in certain efficient systems has been put forward by Jennings et al., who maintain their position strongly despite an argument to the contrary by Lavergne. We identify a specific omission in the calculation of Jennings et al.

Comparison of excited-state energy transfer in arrays of hydroporphyrins (chlorins, oxochlorins) versus porphyrins: rates, mechanisms, and design criteria.

A set of chlorin-chlorin and oxochlorin-oxochlorin dyads has been prepared with components in the same or different metalation states. In each case a 4,4'-diphenylethyne linker spans the respective 10-position of each macrocycle. The dyads have been studied using static and time-resolved absorption and emission spectroscopy, resonance Raman spectroscopy, and electrochemical techniques.

Dipole strengths in the chlorophylls.

Measurements of dipole strengths of chlorophylls in solution are reviewed and correlated. The refractive index dependence is found to be expressible in a simple empirical fashion that does not rely on the concept of vacuum dipole strength. The index dependence in some respects contradicts the dependence expected on the basis of effective field theories.

Dipole and oscillator strengths of chromophores in solution.

A widely published expression for dipole strengths of optical transitions is found to require correction. The proposed adjustment, which involves the refractive index of the solvent in which the strengths are measured, may lead to significant changes in predictions that have been based on the equation. We discuss a closely related issue, the vacuum dipole strength concept, in an empirical context.

Reverse intersystem crossing in rose bengal. II. Fluence dependence of fluorescence following 532 nm laser excitation.

A fluence-dependent fluorescence technique was used to observe reverse intersystem crossing from a certain higher-lying triplet state of rose bengal populated by a single pulse of 532 nm light. The quantum yield of reverse intersystem crossing from this state was determined to be 0.12+/-0.

The relationship of intercompartmental excitation transfer rate constants to those of an underlying physical model.

In studies on photosynthetic systems it is common practice to interpret the results of time-resolved fluorescence experiments on the basis of compartmental, or target, models. Each compartment represents a group of molecules with similar fluorescence characteristics. In cases of practical interest, the members of each compartment are spatially contiguous and make up part of an overall energy-transferring system.

Electronic excitation transfer in the photosynthetic unit: Reflections on work of William Arnold.

Among his many contributions to photosynthesis, William Arnold made critical suggestions about the mechanism of the initial stages of excitation energy transfer and its measurement. Thus he helped found not only the general concept of the photosynthetic unit but also the key idea behind the detailed functional aspects of its 'chlorophyll antenna'. We review the development of these ideas and the modern form in which they have emerged.

Oxygen consumption and diffusion effects in photodynamic therapy.

Effects of oxygen consumption in photodynamic therapy (PDT) are considered theoretically and experimentally. A mathematical model of the Type II mechanism of photooxidation is used to compute estimates of the rate of therapy-dependent in vivo oxygen depletion resulting from reactions of singlet oxygen (1O2) with intracellular substrate. Calculations indicate that PDT carried out at incident light intensities of 50 mW/cm2 may consume 3O2 at rates as high as 6-9 microM s-1.

Studies of excitation energy transfer within the green alga Chlamydomonas reinhardtii and its mutants at 77 K.

The 77 K picosecond fluorescence of intact Chlamydomonas reinhardtii exhibits a 680-nm band (F680) that can be identified with light-harvesting chlorophyll. Analysis of the time and spectral dependence of F680 reveal a forward transfer rate of 1/(15 ps) from this 680-nm species to photosystem II. The possibility of transfer through LHC I, the light-harvesting complex closely associated with photosystem I with a transfer time of 60 to 100 ps, is indicated by analysis of similar data in the 700-720 nm region.

Picosecond fluorescence of R3230AC mammary carcinoma mitochondria after treatment with hematoporphyrin derivative and Photofrin II in vivo.

Hematoporphyrin derivative (HPD) and other porphyrin samples were excited by 20-ps 532-nm laser pulses. Fluorescence was detected using a low-jitter streak camera. Data were fitted to a sum of exponential decay times on the order of picoseconds.

Theory of picosecond-laser-induced fluorescence from highly excited complexes with small numbers of chromophores.

The problem of singlet excitation kinetics and dynamics, especially at high excitation intensities, among a small number of chromophores of a given system has been addressed. A specific scheme for the kinetics is suggested and applied to CPII, a small chlorophyll (Chl)a/b antenna complex the fluorescence lifetime of which has been reported to be independent of excitation intensity over a wide intensity range of picosecond pulses. We have modeled the kinetics from the point of view that Chla molecules in CPII are Förster coupled so that a second excitation received by the group of Chla's either creates a state with two localized excitons or raises the first one to a doubly excited state.

Energy distribution in the photochemical apparatus of Porphyridium cruentum: Picosecond fluorescence spectroscopy of cells in state 1 and state 2 at 77 K.

Excitation energy distribution in Porphyridium cruentum in state 1 and state 2 was investigated by time resolved 77 K fluorescence emission spectroscopy. The fluorescence rise times of phycoerythrin, phycocyanin and allophycocyanin (in cells in state 1 and state 2) were very similar in contrast to the emission from chlorophyll a (Chl a) associated with the two photosystems. In state 2 photosystem II (PSII) Chl a fluorescence emission rose faster than the PSI Chl a emission and decayed more rapidly, and the converse was observed in state 1.

Energy migration and exciton trapping in green plant photosynthesis.

The possible origins of the different fluorescence decay components in green plants are discussed in terms of a random walk and Butler's bipartite model. The interaction of the excitations with the photosystem II reaction centers and, specifically, the regeneration of theses excitations by charge recombination within the reaction centers, are considered. Based on comparisons between fluorescence decay profiles, time-dependent exciton annihilation and photoelectric phenomena, it appears that the fast 200 ps decay component corresponds to primary energy transport from the antenna to the reaction centers and is dominant in filling the photosystem II reaction centers.

Picosecond fluorescence of cryptomonad biliproteins. Effects of excitation intensity and the fluorescence decay times of phycocyanin 612, phycocyanin 645, and phycoerythrin 545.

The fluorescence of purified biliproteins (phycocyanin 645, phycocyanin 612, and phycoerythrin 545) from three cryptomonads, Chroomonas species, Hemiselmis virescens, and Rhodomonas lens, and C-phycocyanin from Anacystis nidulans has been time resolved in the picosecond region with a streak camera system having less than or equal to 2-ps jitter. The fluorescence lifetimes of phycocyanins from Chroomonas species and Hemiselmis virescens are 1.5 +/- 0.

Theory of fluorescence polarization in magnetically oriented photosynthetic systems.

Many cells and cell fragments are known to assume specific alignments with respect to an applied magnetic field. One indicator of this alignment is a difference between the intensities of fluorescence observed in polarizations parallel and perpendicular to the magnetic filed. We calculate these two intensities using a model that assumes axially symmetric membranes and that covers a wide variety of shapes from flat disk to right cylinder.

Fluorescence of light-harvesting chlorophyll a/b-protein complexes: implications for the photosynthetic unit.

To the extent that extracted light-harvesting chlorophyll proteins (LHCPs) retain the chlorophyll configuration which they had in vivo, information on the optical properties of LHCPs is useful for an assessment of the transfer process of the primary excitation energy in photosynthesis. Within this context we report and discuss the implication of three kinds of data on spinach chloroplast LHCP. First, an analysis of the spectroscopic dependence of absorption, polarization and circular dichroism (reported recently by R.