Modeling a Thermoelectric HVAC System for Automobiles

In automobiles thermal energy is used at various energy scales. With regard to reduction of CO₂ emissions, efficient generation of hot and cold temperatures and wise use of waste heat are of paramount importance for car manufacturers worldwide. Thermoelectrics could be a vital component in automobiles of the future. To evaluate the applicability of thermoelectric modules in automobiles, a Modelica model of a thermoelectric liquid–gas heat exchanger was developed for transient simulations. The model uses component models from the object-oriented Modelica library TIL. It was validated based on experimental data of a prototype heat exchanger and used to simulate transient and steady-state behavior. The use of the model within the energy management of an automobile is successfully shown for the air-conditioning system of a car.     

Fast spin-echo MR imaging of the eye

Magnetic resonance imaging of the eye usually includes T2-weighted images both for screening purposes and for characterization of melanoma. Conventional T2-weighted spin-echo (SE) imaging suffers both from long acquisition times and incomplete recovery of the vitreous' signal. A fast SE sequence was therefore compared prospectively with conventional sequences in 29 consecutive patients with lesions of the eye. Fast SE images delineated melanoma and other lesions of the eye from vitreous better than conventional T2-weighted images. Image quality and lesion conspicuity were improved on the fast sequence. Whereas melanoma appeared hypointense to vitreous on both types of images, subretinal effusion was hypointense on fast images and hyperintense on conventional T2-weighted images. Ghosting of the globe, which, however, did not decrease diagnostic value, was more pronounced on fast images. Conventional T2-weighted images may be replaced by fast SE images in MR studies of the eye with a gain in lesion conspicuity and significant time saving.     

Polyclonal stimulation of lymphocytes by macrophages

To analyze the interaction between macrophages and splenic lymphocytes with reference to time and concentration, the Mishell-Dutton system was divided into two experimental steps. Step 1 consisted of the cocultivation of spleen cells with various doses of macrophages for different periods of time, while in step 2 macrophages were removed, spleen cells transferred to fresh petri dishes and cultivated until plaque assay. Cocultivation of spleen cells with high doses of macrophages for 4--8 h markedly enhanced the DNA synthesis and plaque-forming cell (PFC) response of sheep red blood cell-stimulated and unstimulated cultures. A cocultivation longer than 24 h resulted in an inhibition of both DNA synthesis and PFC response of spleen cells. These studies suggest a nonspecific function of macrophages on proliferation and differentiation processes in antibody formation.     

Influence of time and method of alfalfa stand termination on yield,seed quality,N uptake,soil properties and greenhouse gas emissions under different N fertility regimes

A field experiment was conducted in a 7-year old alfalfa stand to compare the influence of time and method of terminating alfalfa stands on crop yield, seed quality, N uptake and recovery of applied N for wheat (Triticum aestivum L.) and canola (Brassica napus L.), soil properties (ammonium-N, nitrate-N, bulk density, total and light fraction organic C and N), and N₂O emissions on a Gray Luvisol (Typic Cryoboralf) loam near Star City, Saskatchewan, Canada. The treatments were a 3 × 3 × 4 factorial combination of three termination methods [herbicide (H), tillage (T), and herbicide + tillage (HT)], three termination times (after cut 1 and cut 2 in 2003, and in spring 2004) and four rates of N (0, 40, 80 and 120 kg N ha⁻¹) applied at seeding to wheat-canola rotation from 2004 to 2007. In the termination year, soil nitrate-N was considerably higher in T or HT treatments than in the H treatment and decreased with delay in termination. In the first crop year, seed and straw yields of wheat grown on T and HT treatments were significantly greater than H alone (by 1,055–1,071 kg seed ha⁻¹ and by 869–929 kg straw ha⁻¹), due to greater content of soil available N in T treatments. Yields decreased with delay in termination time. In general, yield and N uptake in seed and straw, and protein concentration tended to increase with increasing N rate. A greater yield increase occurred on the H compared to T and HT treatments from the first increments of N applied. Nitrous oxide emissions were generally low and there were no treatment differences evident when cumulative 4-year N₂O-N losses were compared. Appropriate N fertilization was able to compensate for yield reductions due to delayed termination timing, but could not do so entirely for yield reductions on the H compared to T or HT termination method. The amounts of TOC, TON, LFOC and LFON after four growing seasons were usually higher or tended to be higher under H treatment than under T treatment in the 0–5 cm soil layer, but the opposite was true in the 5–10 cm or 10–15 cm soil layers.     

Transformation von Uridin- zu Cytidinderivaten durch selektive Aminierung

Transformation of Uridine Derivatives into Cytidines via Selective Amination The synthesis of some 5-fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5-Substituted 4-tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′-deoxy-2′-fluorouridine 9 . The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.     

Synergistic Antimicrobial Activities of Chitosan Mixtures and Chitosan–Copper Combinations

Several recent studies revealed the significant contribution of intensive agriculture to global climate change and biodiversity decline. However, synthetic pesticides and fertilizers, which are among the main reasons for these negative effects, are required to achieve the high performance of elite crops needed to feed the growing world population. Modern agro-biologics, such as biopesticides, biostimulants, and biofertilizers are intended to replace or reduce the current agro-chemicals, but the former are often difficult to combine with the latter. Chitosans, produced from the fisheries’ byproduct chitin, are among the most promising agro-biologics, and copper fungicides are among the most widely used plant protectants in organic farming. However, the two active ingredients tend to form precipitates, hindering product development. Here, we show that partial hydrolysis of a chitosan polymer can yield a mixture of smaller polymers and oligomers that act synergistically in their antifungal activity. The low molecular weight (Mw) of this hydrolysate allows its combination with copper acetate, again leading to a synergistic effect. Combined, these synergies allow a 50% reduction in copper concentration, while maintaining the antifungal activity. This is potentially a significant step towards a more sustainable agriculture.     

Effect of polymer-coated urea and tillage on the dynamics of available N and nitrous oxide emission from Gray Luvisols

Two field experiments were conducted to assess the effectiveness of polymer-coated urea (PCU) vs. conventional urea (urea) in minimizing nitrate accumulation in soil and nitrous oxide (N₂O) emission while optimizing available N supply. The trials were located on Dark Gray Luvisols (Typic Cryoboralf) near Beaverlodge, Alberta (2004–2007) and Star City, Saskatchewan (2004–2006), in the north western Canadian Prairies. The treatments comprised of combinations of two tillage systems (conventional and no tillage), the two forms of urea (applied at commercial rates, 50–60 kg N ha⁻¹), and time of application (side-banded in spring or fall). Tillage had little effect on the measured soil variables. Available N at the anthesis growth stage was higher with spring- than fall-banded N in three of four site-years, and with PCU than urea in two site-years. At seeding, nitrate in the soil layers to 60-cm depth, especially the top 15 cm, was mostly higher for fall- than spring-banded treatments but differed less between the forms of urea. Fall application, therefore, has greater potential for gaseous N and leaching losses early in the growing season when crops have low N requirements, and hence is not advisable. Nitrous oxide emission from spring to fall was higher with the fertilized treatments in three of five site-years and not different between fertilized and unfertilized treatments in the other site-years. At Beaverlodge, N₂O loss was low in 2 years and showed few significant treatment effects. At Star City, N₂O loss was 1.5- to 1.7-fold higher from urea than PCU treatments, and up to 1.5-fold lower from spring than fall application. It is concluded that although PCU can increase available N during the growth period and reduce N₂O loss in some years compared with urea, the time of N application had a consistently greater effect than the type of urea in enhancing crop N recovery and reducing N loss to the environment.     

Hydrophilic trans‐Cyclooctenylated Noncanonical Amino Acids for Fast Intracellular Protein Labeling

Introduction of bioorthogonal functionalities (e.g., trans‐cyclooctene‐TCO) into a protein of interest by site‐specific genetic encoding of non‐canonical amino acids (ncAAs) creates uniquely targetable platforms for fluorescent labeling schemes in combination with tetrazine‐functionalized dyes. However, fluorescent labeling of an intracellular protein is usually compromised by high background, arising from the hydrophobicity of ncAAs; this is typically compensated for by hours‐long washout to remove excess ncAAs from the cellular interior. To overcome these problems, we designed, synthesized, and tested new, hydrophilic TCO‐ncAAs. One derivative, DOTCO‐lysine was genetically incorporated into proteins with good yield. The increased hydrophilicity shortened the excess ncAA washout time from hours to minutes, thus permitting rapid labeling and subsequent fluorescence microscopy.     

Urinary incontinence in rural older women: prevalence, incidence and remission

OBJECTIVES: To determine the prevalence, incidence, and remission rates of urinary incontinence in a large group of older women over a 6-year time span and to assess factors associated with incontinence incidence and remission. DESIGN: Longitudinal cohort study. SETTING: Two rural counties in Iowa. PARTICIPANTS: 2025 women aged 65 years or older residing in rural Iowa, enrolled in the Iowa 65+ Rural Health Study of EPESE (Establishment of Populations for Epidemiologic Studies of the Elderly) were interviewed in person annually for 6 years; specific responses to queries about urinary incontinence were given at baseline, 3-, and 6-year intervals. MEASUREMENTS: Conditional multivariate logistic regression analysis was done to assess the relationship between incontinence symptoms and various factors previously found to be related to incontinence. RESULTS: The baseline prevalence of urge incontinence was 36.3%, and of stress incontinence it was 40.3%. For urge incontinence, the 3-year incidence and remission rates between the third and sixth years were 28.5% and 22.1%, respectively. For stress incontinence, the 3-year incidence and remission rates between years 3 and 6 were 28.6% and 25.1%, respectively. Seventy-six percent and 84% of women who reported no urge or stress incontinence, respectively, at the baseline interview were continent at both follow-up interviews. The only significant factors related to changes in incontinence status were age, which was associated with an increased incidence of urge incontinence (OR 1.11, P = .017, 95% CI 1.019-1.203), and improvement in activities of daily living, which was associated with a increased remission of urge incontinence (OR 0.50, P = .015, 95% CI 0.28-0.9) CONCLUSION: In some older women, urinary incontinence is a dynamic state, with women moving back and forth along a continuum between continence and incontinence. These results are tempered by limitations of the study, which include its questionnaire design and lack of ability to detect potential treatment effect.