Determination of Fluorescence Polarization and Absorption Anisotropy in Molecular Complexes Having Threefold Rotational Symmetry

The current work concerns investigation of the polarization properties of complex molecular ensembles exhibiting threefold (C3) rotational symmetry, particularly with regard to the interplay between their structure and dynamics of internal energy transfer. We assume that the molecules or chromophores in such complexes possess strongly overlapped spectra both for absorption and fluorescence. Such trimeric structures are widely found in biological preparations, as for example the trimer of C-phycocyanin (C-PC). Higher order aggregates, e.g. hex-amers and three-hexamer rods, are also investigated and compared with the trimer case. The theory addresses both steady-state and 8-pulse excitation and establishes some links between them. Monochromophoric, bichro-mophoric and trichromophoric molecular complexes are individually examined. For steady-state excitation, analytical formulas are reported for the degree of fluorescence polarization and absorption anisotropy. It is shown that the polarization is dependent on the chromophore inclination relative to the symmetry axis, the relative efficiencies of absorption and fluorescence by chromophores of different spectral types, and the rates of energy equilibration. To assess the validity of the theory, it has been applied to C-PC aggregates. Here it was found that different C-PC aggregates provide practically identical polarization response. For S-pulse excitation we give analytical formulas for determination of the fluorescence depolarization, and also the depolarization associated with absorption recovery, both for a monochromophoric trimer and some particular cases of bichromophoric trimer. More complicated systems are analyzed by computer modeling. Thus it transpires that the initial polarization anisotropy r(t = 0) takes the value 0.4 for all considered aggregates; the long-time limit r(t →∞) has about the same value as is associated with steady-state excitation. We also show that with steady-state excitation the degree of fluorescence polarization is practically equal for various C3 aggregates of C-PC, and that the major factor determining the polarization is the chromophore orientation relative to the symmetry axis

Mississippi State University Research / Demonstration Module

A final report on the Mississippi State Module Planning Grant prepared by E. T. Kohler and R. C. Maxson in September of 1968

Simulation of the transit-time optical stochastic cooling process in the Cornell Electron Storage Ring

In preparation for a demonstration of optical stochastic cooling in the Cornell Electron Storage Ring (CESR) we have developed a particle tracking simulation to study the relevant beam dynamics. Optical radiation emitted in the pickup undulator gives a momentum kick to that same particle in the kicker undulator. The optics of the electron bypass from pickup to kicker couples betatron amplitude and momentum offset to path length so that the momentum kick reduces emittance and momentum spread. Nearby electrons contribute an incoherent noise. Layout of the bypass line is presented that accommodates optics with a range of transverse and longitudinal cooling parameters. The simulation is used to determine cooling rates and their dependence on bunch and lattice parameters for bypass optics with distinct emittance and momentum acceptance

The Role of Paracrine and Autocrine Signaling in the Early Phase of Adipogenic Differentiation of Adipose-derived Stem Cells.

INTRODUCTION: High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways. METHODS AND RESULTS: Adipogenic differentiation of human adipose-derived stem cells (ASCs) cultured in a microfluidic system was investigated under perfusion conditions with an adipogenic medium or an adipogenic medium supplemented with supernatant from differentiating ASCs (conditioned medium). Conditioned medium increased adipogenic differentiation compared to adipogenic medium with respect to accumulation of lipid-filled vacuoles and gene expression of key adipogenic markers (C/EBPα, C/EBPβ, C/EBPδ, PPARγ, LPL and adiponectin). The positive effects of conditioned medium were observed early in the differentiation process. CONCLUSIONS: Using different cell densities and microfluidic perfusion cell cultures to suppress the effects of cell-released factors, we have demonstrated the significant role played by auto- or paracrine signaling in adipocyte differentiation. The cell-released factor(s) were shown to act in the recruitment phase of the differentiation process

Better Pumps: Promoting Reliable Water Infrastructure for Everyone

Approximately 90 million people in Africa lack access to safe drinking water, despite having water infrastructure installed in their community. The India Mark II and the Afridev handpumps are among the most widely used handpumps in the world. Sadly, studies show that approximately 30% of these handpumps are non-operational due to failures of the bearings, seals, head flange, and other common components. The Better Pumps team of the Collaboratory provides engineering support for partners who are working to improve handpump sustainability. We have partnered with Tony Beers and AlignedWorks to validate a bearing test methodology for the India Mark II handpump. By modifying the loading conditions in our handpump test machine, we were able to replicate failures observed by AlignedWorks in a field trial of their bearing design. However, these modifications caused our test machine tabletop to noticeably deflect, so we made modifications to stiffen the tabletop. We partnered with Matt Schwiebert and Living Water International to test new seal designs for the India Mark II and Afridev handpumps. Seal performance data collected by the team was used to validate a new design in advance of field trials by Living Water International. We developed and performed clear cylinder testing on the seals to visualize the leak paths. A new Afridev testing apparatus is being designed to test the longevity of the Afridev bearings and seals. Test methodologies and results are reported. Funding for this work provided by The Collaboratory for Strategic Partnerships and Applied Research.https://mosaic.messiah.edu/engr2022/1000/thumbnail.jp

Medical treatment of prolactinomas.

Prolactinomas, the most prevalent type of neuroendocrine disease, account for approximately 40% of all pituitary adenomas. The most important clinical problems associated with prolactinomas are hypogonadism, infertility and hyposexuality. In patients with macroprolactinomas, mass effects, including visual field defects, headaches and neurological disturbances, can also occur. The objectives of therapy are normalization of prolactin levels, to restore eugonadism, and reduction of tumor mass, both of which can be achieved in the majority of patients by treatment with dopamine agonists. Given their association with minimal morbidity, these drugs currently represent the mainstay of treatment for prolactinomas. Novel data indicate that these agents can be successfully withdrawn in a subset of patients after normalization of prolactin levels and tumor disappearance, which suggests the possibility that medical therapy may not be required throughout life. Nevertheless, multimodal therapy that involves surgery, radiotherapy or both may be necessary in some cases, such as patients who are resistant to the effects of dopamine agonists or for those with atypical prolactinomas. This Review reports on efficacy and safety of pharmacotherapy in patients with prolactinomas

Status, trends, and population demographics of selected sportfish species in the La Grange Reach of the Illinois River

Abstract Sportfish species, specifically Yellow Bass Morone mississippiensis, White Bass Morone chrysops, Largemouth Bass Micropterus salmoides, Bluegill Lepomis macrochirus, Black Crappie Pomoxis nigromaculatus, and White Crappie P. annularis, often drive economically valuable fisheries in large river systems, including the Upper Mississippi River System (UMRS).  Within the Illinois River, part of the UMRS, these species are routinely sampled by an ongoing long-term fisheries monitoring program.  Through this program, we investigated long-term trends (1993-2017) in catch rates and relative weights and quantified demographic rates from 2012-2016. We found all six species, with the exception of Yellow Bass, to have declining catch rates with this decline being most stark in larger, older fishes.  Population demographics for Yellow Bass, White Bass, Bluegill, and Black Crappie suggest populations are dominated by younger individuals, with only Black Crappie regularly living to age 3 and older, which may be driving population declines.  There are many environmental stressors acting on the Illinois River that could be contributing to the lack of older and larger fishes, including, but not limited to, navigation efforts, altered hydrology, pollution, sedimentation, lack of overwintering habitat, and introduction of invasive species.  Results of this study demonstrate that additional research to understand mechanisms driving reduced abundance and stunted age structure are needed to identify effective management actions that would benefit populations of recreationally valuable sportfish species

Status, trends, and population demographics of selected sportfish species in the La Grange Reach of the Illinois River

Sportfish species, specifically Yellow Bass Morone mississippiensis, White Bass Morone chrysops, Largemouth Bass Micropterus salmoides, Bluegill Lepomis macrochirus, Black Crappie Pomoxis nigromaculatus, and White Crappie P. annularis, often drive economically valuable fisheries in large river systems, including the Upper Mississippi River System (UMRS). Within the Illinois River, part of the UMRS, these species are routinely sampled by an ongoing long-term fisheries monitoring program. Through this program, we investigated long-term trends (1993-2017) in catch rates and relative weights and quantified demographic rates from 2012-2016. We found all six species, with the exception of Yellow Bass, to have declining catch rates with this decline being most stark in larger, older fishes. Population demographics for Yellow Bass, White Bass, Bluegill, and Black Crappie suggest populations are dominated by younger individuals, with only Black Crappie regularly living to age 3 and older, which may be driving population declines. There are many environmental stressors acting on the Illinois River that could be contributing to the lack of older and larger fishes, including, but not limited to, navigation efforts, altered hydrology, pollution, sedimentation, lack of overwintering habitat, and introduction of invasive species. Results of this study demonstrate that additional research to understand mechanisms driving reduced abundance and stunted age structure are needed to identify effective management actions that would benefit populations of recreationally valuable sportfish species.is peer reviewedOpe