Alteration of the growth rate and lag time of Leuconostoc mesenteroides NRRL-B523

Bacterial profile modification is an important enhanced oil recovery technique used to direct injected water into a reservoir's low permeability zone containing trapped crude oil. During water flooding, the use of bacteria to plug the high permeability water zone and divert flow into the oil-bearing low-permeability zone will have a significant economic impact. However, during the field implementation of bacterial profile modification, the rapid growth of bacteria near the injection well bore may hinder the subsequent injection of growth media so that profile modification of the reservoir occurs only in the immediate vicinity of the well bore. By slowing the growth rate and prolonging the lag phase, the onset of pore-space plugging may be delayed and the biologically active zone extended deep into the reservoir. High substrate loading, high pH values, and the addition of the growth inhibitors sodium dodecylsulfate and sodium benzoate have been used in combination to alter the growth characteristics of Leuconostoc mesenteroides NRRL-B523 grown in batch conditions. The highest sucrose concentration used in these studies, 500 g/L, produced lag times 12-fold greater than the slowest lag times achieved at low sucrose concentrations. When L. mesenteroides was grown in media containing 500 g/L sucrose, an alkaline pH value threshold was found above which bacteria did not grow. At this threshold pH value of 8.1, an average lag time of 200 h was observed. Increasing the concentration of sodium benzoate had no effect on lag time, but reduced the growth rate until the threshold concentration of 0.6%, above which bacteria did not grow. Last, it was found that a solution of 0.075 m M sodium dodecylsulfate in media containing 15 g/L sucrose completely inhibited bacterial growth. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 72: 603–610, 2001.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34339/1/25_ftp.pd

Materials for Diabetes Therapeutics

This review is focused on the materials and methods used to fabricate closed-loop systems for type 1 diabetes therapy. Herein, we give a brief overview of current methods used for patient care and discuss two types of possible treatments and the materials used for these therapies–(i) artificial pancreases, comprised of insulin producing cells embedded in a polymeric biomaterial, and (ii) totally synthetic pancreases formulated by integrating continuous glucose monitors with controlled insulin release through degradable polymers and glucose-responsive polymer systems. Both the artificial and the completely synthetic pancreas have two major design requirements: the device must be both biocompatible and be permeable to small molecules and proteins, such as insulin. Several polymers and fabrication methods of artificial pancreases are discussed: microencapsulation, conformal coatings, and planar sheets. We also review the two components of a completely synthetic pancreas. Several types of glucose sensing systems (including materials used for electrochemical, optical, and chemical sensing platforms) are discussed, in addition to various polymer-based release systems (including ethylene-vinyl acetate, polyanhydrides, and phenylboronic acid containing hydrogels).Juvenile Diabetes Research Foundation International (17-2007-1063)Leona M. and Harry B. Helmsley Charitable Trust (09PG-T1D027)United States. National Institutes of Health (F32 EB011580-01

Betriebsverhalten einer Wärmepumpenanlage mit Luftkollektor und Erdspeicher

This study is concerned with the investigation of the performance of a heat pump system with solar air heater and earth storage as a source of heat. After the experimental check of the collector and the earth storage a complete heating system was constructed and studied over a heating period. The heating system was simulated by a computer program. This program treats the solar air collector and the earth storage by the measured characteristics of their performance. A house simulation program used the ambient temperature, the solar radiation and wind speed to calculate the heating load of a residental house. The calculations resulting from the simulation program showed the performance of the system under the different weather conditions of Jülich and Hamburg as well as the suitable regulation and the right dimensions of the mean components

Betriebsverhalten einer Wärmepumpenanlage mit Luftkollektor und Erdspeicher

This study is concerned with the investigation of the performance of a heat pump system with solar air heater and earth storage as a source of heat. After the experimental check of the collector and the earth storage a complete heating system was constructed and studied over a heating period. The heating system was simulated by a computer program. This program treats the solar air collector and the earth storage by the measured characteristics of their performance. A house simulation program used the ambient temperature, the solar radiation and wind speed to calculate the heating load of a residental house. The calculations resulting from the simulation program showed the performance of the system under the different weather conditions of Jülich and Hamburg as well as the suitable regulation and the right dimensions of the mean components