Fourier transform infrared microscopic imaging: effects of estrogen and estrogen deficiency on fracture healing in rat femurs

Infrared spectroscopic imaging with 6-10 microm spatial resolution was used to characterize the changes in fracture callus mineral content, carbonate content, mineral crystallinity, and collagen maturity in femurs of 3-month-old ovariectomized rats treated with estrogen (estrogen sufficiency) or vehicle (estrogen deficiency). Comparisons were also made in these animals to cortical bone at a distance from the callus. Analyses at 4, 8, and 12 weeks post fracture demonstrated that healing was accelerated in the estrogen-sufficient animals as demonstrated by increasing mineral content and collagen maturity and decreasing carbonate incorporation.     

Efficient web-based open and distance learning services

In this paper, we present data management issues faced during the design and development of an open distance learning system for the University of Patras, Greece. In order to handle data efficiently, as required in a web tele-training application, for each type of information maintained, different strategies must be deployed according to their behaviour and structure. The diversity and complexity of data, the network aspect of the application and web deficiencies impose an architecture design incorporating a plethora of technologies and tools that must be integrated in such a fashion that they efficiently organise these data preserving their relationships. This presents a software engineering challenge requiring coherence of solutions at all levels: structures, consistency, security, models, and protocols. The paper presents the data components of an open and distance learning (ODL) system that access the information stored in a database and the file system, their underlying technology, their interaction with the network services, and features regarding the ways they address issues faced in an open vendor-independent distance learning environment and outlines the system's overall architecture. In addition, this paper presents the architecture, the design and the services of a network-based information system that supports open and distance learning activities. The open and distance learning information system (ODLIS) offers synchronous and asynchronous distance learning and management of information system (MIS) services to support the educational procedure. The ODLIS is a web-based application, which runs over the Internet using real time protocols.     

Sulfur infiltration and allotrope formation in porous cathode hosts for lithium-sulfur batteries

We investigate sulfur infiltration and formation of lower order allotropes in heated porous hosts during fabrication of lithium-sulfur (Li-S) battery cathodes. Sulfur existence in cathode ultramicropores has been an important question for Li-S batteries, as ultramicropores reduce the polysulfides “shuttle effect” but also delay sulfur dissolution and Li⁺ ion diffusion in the trapped solid sulfur. A novel continuum-level model is presented including heat transfer and sulfur infiltration, either from the top of a porous host or from the porous host particle surface, and taking into account the pore size distribution. A novel decay factor in modeling sulfur infiltration incorporates the pore wall repulsion energy and allotrope formation energy (predicted by density functional theory [DFT] simulations). Simulations are performed for a microporous carbon fabric host and an activated carbon powder host with bimodal micropore and macropore size distribution, with Raman and X-ray photoemission spectroscopy (XPS) spectroscopy confirming the predicted existence of linear S₆ and S₄ in ultramicropores.     

Effect of anilinopyrimidine resistance on aflatoxin production and fitness parameters in Aspergillus parasiticus Speare

Mutants of Aspergillus parasiticus resistant to the anilinopyrimidine fungicides were isolated at a high mutation frequency after UV-mutagenesis and selection on media containing cyprodinil. In vitro fungitoxicity tests resulted in the identification of two predominant resistant phenotypes that were highly (R₁-phenotype) and moderately (R₂-phenotype) resistant to the anilinopyrimidines cyprodinil, pyrimethanil and mepanipyrim. Cross-resistance studies with fungicides from other chemical groups showed that the highly resistance mutation(s) did not affect the sensitivity of R₁-mutant strains to fungicides affecting other cellular pathways. Contrary to that, a reduction in the sensitivity to the triazoles epoxiconazole and flusilazole, the benzimidazole carbendazim, the phenylpyrrole fludioxonil, the dicarboximide iprodione and to the strobilurin-type fungicide pyraclostrobin was observed in R₂-mutant strains. Study of fitness parameters of anilinopyrimidine-resistant strains of both phenotypic classes showed that all R₁ mutant strains had mycelial growth rate, sporulation and conidial germination similar to or even higher than the wild-type parent strain, while these fitness parameters were negatively affected in R₂ mutant strains. Analysis of the aflatoxin production showed that most R₁ mutant strains produced aflatoxins at concentrations markedly higher than the wild-type parent strain. A considerable reduction in the aflatoxin production was observed on cultured medium and on wheat grains by all R₂ mutant strains, indicating a possible correlation between fitness penalties and aflatoxigenic ability of A. parasiticus. The potential risk of increased aflatoxin contamination of agricultural products and their byproducts by the appearance and predominance of highly aflatoxigenic mutant strains of A. parasiticus resistant to the anilinopyrimidines is discussed.     

Sensitivity of Penicillium expansum field isolates to tebuconazole, iprodione, fludioxonil and cyprodinil and characterization of fitness parameters and patulin production

A total of 236 Penicillium expansum field isolates from decayed apple fruit collected from packinghouses and processing industries located in the region of Imathia, Northern Greece were tested for their sensitivity to tebuconazole, fludioxonil, iprodione and cyprodinil. Preliminary fungitoxicity tests on the response of the isolates showed several phenotypes, distinguished according to their sensitivity to fungicides tested. The EC₅₀ values ranged from 0.64 to 5 (average = 0.98) μg/ml for iprodione, 0.9 to 7.3 (average = 2.66) μg/ml for tebuconazole, 0.008 to 1.28 (average = 0.55) μg/ml for cyprodinil and from 0.013 to 0.47 (average = 0.08) μg/ml for fludioxonil. A bimodal distribution of the EC₅₀ values of isolates with distinct sensitive and resistant populations to fludioxonil and tebuconazole were observed. In the case of cyprodinil, a much broader, hundred-fold, range of sensitivity was found, probably indicating that some isolates are relatively insensitive to cyprodinil compared to the most sensitive ones. Isolates exhibiting simultaneously reduced sensitivity to tebuconazole and fludioxonil or tebuconazole and iprodione or to tebuconazole and cyprodinil were also observed at low frequencies. A small portion of the population (7.5%) showed multiple resistance to tebuconazole, fludioxonil and iprodione. Study of fitness determining parameters showed that the resistance to tebuconazole, fludioxonil and iprodione had a significant adverse effect on mycelial growth rate and pathogenicity. Contrary to that, these fitness parameters were not affected in the isolates showing reduced sensitivity to cyprodinil. Analysis of patulin production on YES-agar growth medium and on artificially inoculated apple fruit showed that all isolates were mycotoxigenic. Most of the cyprodinil-insensitive isolates produced patulin at concentrations similar to or relatively higher (up to 1.5-fold on growth medium) than the sensitive ones. In contrast, a significant reduction (up to 98% of multiple resistant isolates) in patulin production was observed in all other phenotypes, indicating an adverse effect of fitness penalties on the mycotoxigenic ability of resistant isolates. The above mentioned data clearly show a considerable risk for the selection of P. expansum isolates resistant to fludioxonil, iprodione, tebuconazole and cyprodinil. The potential risk of increased patulin contamination of apples and their byproducts by the appearance and predominance of highly mycotoxigenic isolates of P. expansum resistant to the anilinopyrimidines is discussed.     

Efficient algorithms for constructing broadcast disks programs in asymmetric communication environments

A well-known technique for broadcast program construction is the Broadcast Disks technique. However, in the Broadcast Disks approach there are some important disadvantages. For example some parts of the broadcast program remain empty during the construction procedure and the disk relative frequencies have to be selected very carefully. This paper gives a new approach of the broadcast program construction in a Broadcast Disk System, presenting three new algorithms, which face successfully these problems. According to this approach, the broadcast program is constructed with the minimum possible length, while retaining the selected disk relative frequencies and keeps the average delays on retrieving data-items low. The constructed broadcast programs have no empty parts, and retain their desired properties in any numbered combination of disk relative frequencies. We implemented all methods in a simulator application and experimental results show that our approach is more efficient than Broadcast Disks in all cases.     

Optimal configuration of OSPF aggregates

Open Shortest Path First (OSPF) is a popular protocol for routing within an autonomous system (AS) domain. In order to scale for large networks containing hundreds and thousands of subnets, OSPF supports a two-level hierarchical routing scheme through the use of OSPF areas. Subnet addresses within an area are aggregated, and this aggregation is a crucial requirement for scaling OSPF to large AS domains, as it results in significant reductions in routing table sizes, smaller link-state databases, and less network traffic to synchronize the router link-state databases. On the other hand, address aggregation also implies loss of information about the length of the shortest path to each subnet, which in turn, can lead to suboptimal routing. We address the important practical problem of configuring OSPF aggregates to minimize the error in OSPF shortest-path computations due to subnet aggregation. We first develop an optimal dynamic programming algorithm that, given an upper bound k on the number of aggregates to be advertised and a weight assignment function for the aggregates, computes the k aggregates that result in the minimum cumulative error in the shortest-path computations for all source-destination subnet pairs. Subsequently, we tackle the problem of assigning weights to OSPF aggregates such that the cumulative error in the computed shortest paths is minimized. We demonstrate that, while for certain special cases (e.g., unweighted cumulative error) efficient optimal algorithms for the weight assignment problem can be devised, the general problem itself is NP-hard. Consequently, we have to rely on search heuristics to solve the weight assignment problem. To the best of our knowledge, our work is the first to address the algorithmic issues underlying the configuration of OSPF aggregates and to propose efficient configuration algorithms that are provably optimal for many practical scenarios.     

Reengineering of the Laundry Service at a University Campus: A Continuous-Improvement Quality-Management Methodology

The Department of Auxiliary Services of the University of Miami had been the recipient of numerous anecdotal complaints by resident students regarding the service of the laundry system offered at the residential on-campus dormitories (students often complained about nonworking and/or busy machines). In this paper we present a holistic systems approach that utilizes total quality management and quantitative decision-making tools in a seamless fashion to improve the students' satisfaction and perception related to the laundry system. At the same time, other departmental important objectives, such as the implementation of an ongoing in-house procedure that supports its continuous-improvement program, are taken into account. Results that document the improved system performance are further presented.     

Noncontact optical imaging in mice with full angular coverage and automatic surface extraction

During the past decade, optical imaging combined with tomographic approaches has proved its potential in offering quantitative three-dimensional spatial maps of chromophore or fluorophore concentration in vivo. Due to its direct application in biology and biomedicine, diffuse optical tomography (DOT) and its fluorescence counterpart, fluorescence molecular tomography (FMT), have benefited from an increase in devoted research and new experimental and theoretical developments, giving rise to a new imaging modality. The most recent advances in FMT and DOT are based on the capability of collecting large data sets by using CCDs as detectors, and on the ability to include multiple projections through recently developed noncontact approaches. For these to be implemented, we have developed an imaging setup that enables three-dimensional imaging of arbitrary shapes in fluorescence or absorption mode that is appropriate for small animal imaging. This is achieved by implementing a noncontact approach both for sources and detectors and coregistering surface geometry measurements using the same CCD camera. A thresholded shadowgrammetry approach is applied to the geometry measurements to retrieve the surface mesh. We present the evaluation of the system and method in recovering three-dimensional surfaces from phantom data and live mice. The approach is used to map the measured in vivo fluorescence data onto the tissue surface by making use of the free-space propagation equations, as well as to reconstruct fluorescence concentrations inside highly scattering tissuelike phantom samples. Finally, the potential use of this setup for in vivo small animal imaging and its impact on biomedical research is discussed.