Brown Tide Symposium and Workshop : 15-16 July 1991

The 'brown tide' bloom of an aberrant Chrysophyte sp. phytoplankter occurred for more than 18 months and extended into both upper (cover map) and lower Laguna Madre, Texas. Great concern for the Laguna Madre ecosystem was shown during the brown tide event by local, state and regional groups, but little previous knowledge was available about this unusual phytoplankton bloom. Since field data had been collected by an ongoing UTMSI field program in the Laguna, it was felt that a workshop format meeting should be convened with national and international experts to discuss the data and results on brown tide and other unusual phytoplankton blooms. A relatively quick response was needed as planning for the workshop started in May 1991 for a meeting date in July, with support supplied by the Gulf of Mexico Program of U.S. Environmental Protection Agency (Grant No. X 006242-01-0), The Resource Protection Division of the Texas Parks and Wildlife Department and The University of Texas Marine Science Institute. This report includes the agenda, abstracts of presentations and summary of findings by the workshop participants. The participants also strongly agreed that long term research support was necessary to further understand the brown tide bloom and its effects. To that end, a resolution was drafted and unanimously approved by all the workshop participants.September 1991Marine Scienc

Autonomous space processor for orbital debris

This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system

Exciton and Carrier Dynamics in 2D Perovskites

Two-dimensional Ruddlesden-Popper hybrid lead halide perovskites have become a major topic in perovskite optoelectronics. Here, we aim to unravel the ultrafast dynamics governing the evolution of charge carriers and excitons in these materials. Using a combination of ultrabroadband time-resolved THz (TRTS) and fluorescence upconversion spectroscopies, we find that sequential carrier cooling and exciton formation best explain the observed dynamics, where exciton-exciton interactions play an important role in the form of Auger heating and biexciton formation. We show that the presence of a longer-lived population of carriers is due to these processes and not to a Mott transition. Therefore, excitons still dominate at laser excitation densities. We use kinetic modeling to compare the phenethylammonium and butylammonium organic cations while investigating the stability of the resulting films. In addition, we demonstrate the capability of using ultrabroadband TRTS to study excitons in large binding energy semiconductors through spectral analysis at room temperature

Future Marine Zooplankton Research- A Perspective

During the Second Marine Zooplankton Colloquium (MZC2) 3 issues were added to those developed 11 yr ago during the First Marine Zooplankton Colloquium (MZC1). First, we focused on hot spots, i.e., locations where zooplankton occur in higher than regular abundance and/or operate at higher rates. We should be able to determine the processes leading to such aggregations and rates, and quantify their persistence. Second, information on the level of individual species, even of highly abundant ones, is limited. Concerted efforts should be undertaken with highly abundant to dominant species or genera (e.g., Oithona spp., Calanus spp., Oikopleura spp., Euphausia superba) to determine what governs their abundance and its variability. Third, zooplankton clearly influence biogeochemical cycling in the ocean, but our knowledge of the underlying processes remains fragmentary. Therefore a thorough assessment of variables that still need to be quantified is required to obtain an understanding of zooplankton contributions to biogeochemical cycling. Combining studies on the 7 issues from MZC1 with the 3 from MZC2 should eventually lead to a comprehensive understanding of (1) the mechanisms governing the abundance and existence of dominant zooplankton taxa, and (2) the control of biodiversity and biocomplexity, for example, in the tropical ocean where diversity is high. These recommendations come from an assemblage of chemical, physical and biological oceanographers with experience in major interdisciplinary studies, including modeling. These recommendations are intended to stimulate efforts within the oceanographic community to facilitate the development of predictive capabilities for major biological processes in the ocean

Stability and Radiation Damage of Protein Crystals as Studied by Means of Molecular Dynamics and Monte Carlo Simulation

Molecular Dynamics (MD) and Monte Carlo (MC) simulations of crystals can help in interpretation of experimental X-ray crystallography data. Particularly, they can be useful for understanding how various crystallization techniques affect protein conformational plasticity within the crystal lattice and the stability of biomolecular crystals. The latter has become especially important since the modern and extremely intense X-ray radiation sources (such as free electron lasers, FELs) appeared recently. In the present study we were able to show by means of computer simulations that the lysozyme crystals obtained using the Langmuir-Blodgett technique have an advantage over the classical ones (\u201cHanging Drop\u201d) in terms of their thermal stability as well as their stability against the radiation damage. We also demonstrate an important role of crystal water dynamics for stability of protein crystals

Abstract P-2: Multiscale Molecular Dynamics Simulations of the Skin Membranes as a Tool for the Interpretation of the Transmission Electron Microscopy Images

Background: Human skin can inhibit chemical penetration which limits the clinical applications of transdermal drug delivery. The stratum corneum (SC) is the primary barrier and organized in lamellar membranes containing the lipids of ceramides (CER), free fatty acids (FFA), and cholesterol (CHOL). One of the most widely used ways to overcome the SC is the addition of chemical penetration enhancers (CPEs) to active ingredients. There are various methods, which have been employed to explore the mechanisms by which CPEs with drugs can change the morphology of SC including transmission electron microscopy. Here, we propose to use multiscale coarse-grained (CG) molecular dynamics (MD) simulations for the interpretation of the images of the SC from the electron microscopy experiments. Methods: We utilized the MARTINI force field for the CG simulations. We employed the mixed-lipid bilayer model of SC consisting of CER, CHOL, and FFA in a 1:1:1 molar ratio assembled with CHARMM-GUI web-service. The systems of the SC model membrane and various enhancers were simulated in the NPT ensemble with the polarizable water model and the reaction field approach for the long-range electrostatics with the usage of Gromacs 2019.4 software. Results: The membrane model was validated with standard characteristics: thickness, diffusion of the lipids, order parameters, and density profiles. After, we have added CPEs and active ingredients to the systems: menthol and osthole as control simulations, ethanol with linoleic acid and lidocaine as test simulations. We have observed the membrane desegregation in the case of menthol and osthole formulations similar to the published results while the permeation of lidocaine with ethanol and linoleic acid did not cause the disruption of the membranes but increased its fluidity and permeability properties. Conclusion: The method of multiscale coarse-grained molecular dynamics simulations can be utilized for the prediction and interpretation of morphology change of SC in addition to various substances

Explicit and Implicit Emotion Processing in the Cerebellum: A Meta‑analysis and Systematic Review

The cerebellum’s role in affective processing is increasingly recognized in the literature, but remains poorly understood, despite abundant clinical evidence for affective disruptions following cerebellar damage. To improve the characterization of emotion processing and investigate how attention allocation impacts this processing, we conducted a meta-analysis on task activation foci using GingerALE software. Eighty human neuroimaging studies of emotion including 2761 participants identified through Web of Science and ProQuest databases were analyzed collectively and then divided into two categories based on the focus of attention during the task: explicit or implicit emotion processing. The results examining the explicit emotion tasks identified clusters within the posterior cerebellar hemispheres (bilateral lobule VI/Crus I/II), the vermis, and left lobule V/VI that were likely to be activated across studies, while implicit tasks activated clusters including bilateral lobules VI/Crus I/II, right Crus II/lobule VIII, anterior lobule VI, and lobules I-IV/V. A direct comparison between these categories revealed five overlapping clusters in right lobules VI/Crus I/Crus II and left lobules V/VI/Crus I of the cerebellum common to both the explicit and implicit task contrasts. There were also three clusters activated significantly more for explicit emotion tasks compared to implicit tasks (right lobule VI, left lobule VI/vermis), and one cluster activated more for implicit than explicit tasks (left lobule VI). These findings support previous studies indicating affective processing activates both the lateral hemispheric lobules and the vermis of the cerebellum. The common and distinct activation of posterior cerebellar regions by tasks with explicit and implicit attention demonstrates the supportive role of this structure in recognizing, appraising, and reacting to emotional stimuli