Platelet-Rich Plasma Promotes the Proliferation of Human Muscle Derived Progenitor Cells and Maintains Their Stemness

Human muscle-derived progenitor cells (hMDPCs) offer great promise for muscle cell-based regenerative medicine; however, prolonged ex-vivo expansion using animal sera is necessary to acquire sufficient cells for transplantation. Due to the risks associated with the use of animal sera, the development of a strategy for the ex vivo expansion of hMDPCs is required. The purpose of this study was to investigate the efficacy of using platelet-rich plasma (PRP) for the ex-vivo expansion of hMDPCs. Pre-plated MDPCs, myoendothelial cells, and pericytes are three populations of hMDPCs that we isolated by the modified pre-plate technique and Fluorescence Activated Cell Sorting (FACS), respectively. Pooled allogeneic human PRP was obtained from a local blood bank, and the effect that thrombin-activated PRP-releasate supplemented media had on the ex-vivo expansion of the hMDPCs was tested against FBS supplemented media, both in vitro and in vivo. PRP significantly enhanced short and long-term cell proliferation, with or without FBS supplementation. Antibody-neutralization of PDGF significantly blocked the mitogenic/proliferative effects that PRP had on the hMDPCs. A more stable and sustained expression of markers associated with stemness, and a decreased expression of lineage specific markers was observed in the PRP-expanded cells when compared with the FBS-expanded cells. The in vitro osteogenic, chondrogenic, and myogenic differentiation capacities of the hMDPCs were not altered when expanded in media supplemented with PRP. All populations of hMDPCs that were expanded in PRP supplemented media retained their ability to regenerate myofibers in vivo. Our data demonstrated that PRP promoted the proliferation and maintained the multi-differentiation capacities of the hMDPCs during ex-vivo expansion by maintaining the cells in an undifferentiated state. Moreover, PDGF appears to be a key contributing factor to the beneficial effect that PRP has on the proliferation of hMDPCs. © 2013 Li et al

The fresh water lens in a barrier beach.

Oceanic landmasses, under natural conditions commonly develop a body of fresh groundwater. This freshwater body assumes the form of a lens floating on the underlying seawater, and is usually thickest at the central part of the landmass tapering to a thin edge at the shore margins. With certain unique exceptions as will be described herein the flow moves from the thickest part of the lens outward and upward to the shoreline. The extent of a freshwater lens depends primarily on landmass width, permeability, rainfall, and tidal range. As a part of a general study of the freshwater lens phenomena, a field investigation was made at East Beach, the largest of the Rhode Island barrier beaches.(from paper

Preliminary hydrographic surveys of some ponds in the Pelican Cays, Belize, Central America

Hydrographic and hydrologic surveys of three ponds in the Pelican Cays Group were carried out using hand-held sonar, pressure transducer tide loggers, and YSI temperature-salinity probes. These ponds characteristically have a circular pattern with steeply sloping sides. The pond depths range from 4.6 m in a small pond with a diameter of 100 m to 15.2 m in a large pond with a diameter of 840 m; in general, depth increases with increasing pond size. Depths ranged from 15.2 m for a distance of 100 m between cays to 28.7 m for a distance of 1,150 m. Pond salinities averaged 35.3 ppt with a range of 1.5 ppt, and temperatures averaged 31.4°C with surface temperatures about 1°C higher than bottom temperatures

Asymmetric variation of Ghyben-Herzberg lens.

An asymmetric freshwater lens is shown to exist in a long narrow coastal barrier beach bounded on 1 side by a salt water lagoon and on the other by the ocean. Field measurements of ground-water specific conductance and water table elevations show the lens to average approximately 17 ft (5m) in maximum thickness and to be thicker on the side toward the lagoon. The asymmetry is apparently due to an effective mean sea level higher than actual mean sea level on the ocean side which occurs because of tide and wave action on a sloping ocean beach. -from ASCE Publications Abstract

LOW HEAD HYDROELECTRIC POTENTIAL AT AN EXISTING DAM.

As a part of the United States Department of Energy Low Head Hydropower Program the feasibility of a low head hydroelectric installation on the Blackstone River flow at Woonsocket Falls, the site of an existing flood control dam, has been evaluated by a multidisciplinary study team. A computer system model was used to evaluate the interaction of engineering, economic, and financial cost factors. The major engineering factors are net head, river flow, power plant rating, and power plant efficiency schedule. The energy output was determined from these inputs. Economic and financial factors include power demands of municipal users, power rate structures, wheeling costs, production costs, power plant cost schedule, and production cost inflation. Yearly cash flow and utility functions (performance indices) are the primary output

Modeling sodium and chloride in surface streams during base flows

Sodium and chloride contamination of shallow groundwater can be frequently attributed to three major sources: (1) Individual sewage disposal systems (ISDS); (2) road salt application during winter deicing activities; and/or (3) road salt storage. Effluent streams in a large reservoir watershed were sampled during baseflow conditions. Sodium and chloride concentrations were regressed against different land use types including roadway, residential, commercial, industrial, agricultural, and forest areas. Results indicate that roadway areas are the largest single influence of sodium and chloride concentrations. Data from other watersheds are compared to the developed relationships and agreement is favorable. Additionally, a mass balance is performed and indicates that, typically, roadway deicing activity in the test watershed can potentially introduce far greater amounts of sodium and chloride in the local groundwater than the next greatest influence, residential septic systems