Technique based on LED multispectral imaging and multivariate analysis for monitoring the conservation state of the Dead Sea Scrolls

The aim of this project is the development of a noninvasive technique based on LED multispectral imaging (MSI) for monitoring the conservation state of the Dead Sea Scrolls (DSS) collection. It is well-known that changes in the parchment reflectance drive the transition of the scrolls from legible to illegible. Capitalizing on this fact, we will use spectral imaging to detect changes in the reflectance before they become visible to the human eye. The technique uses multivariate analysis and statistical process control theory. The present study was carried out on a "sample" parchment of calfskin. The monitoring of the surface of a commercial modern parchment aged consecutively for 2 h and 6 h at 80 °C and 50% relative humidity (ASTM) was performed at the Imaging Lab of the Library of Congress (Washington, DC, U.S.A.). MSI is here carried out in the vis-NIR range limited to 1 μm, with a number of bands of 13 and bandwidths that range from about 10 nm in UV to 40 nm in IR. Results showed that we could detect and locate changing pixels, on the basis of reflectance changes, after only a few "hours" of aging.     

A Gel‐Based Model of Selective Cell Motility: Implications for Cell Sorting,Diagnostics, and Screening

The ability to precisely control cell‐loaded material systems is essential for in vitro testing of novel therapeutics poised to advance to clinic. In this report, unique patterns of cell migration are devised into an in vitro gel‐in‐gel model for the purpose of obtaining cell response data to potentially therapeutic chemical agonists. The model consists of co‐cultures in a cell‐loaded microgel invading an acellular “sorting” gel. Material properties including biophysical and chemical compositions of the sorting gel are carefully controlled to guide a desired cell‐specific behavior, leading to massive tumor cell invasion by amoeboid migration mechanisms. Optical transparency enables straightforward and high‐throughput measurements of outgrowth response in the presence of either chemical and photoradiation therapy. Important dosing and drug sensitivity information are obtained with the gel‐in‐gel model using no more than a light microscope, without further need for arduous genomic or proteomic screening of the tissue samples.     

The Multi-strand Graph for a PTZ Tracker

High-resolution images can be used to resolve matching ambiguities between trajectory fragments (tracklets), which is a key challenge in multiple-target tracking. A pan–tilt–zoom (PTZ) camera, which can pan, tilt and zoom, is a powerful and efficient tool that offers both close-up views and wide area coverage on demand. The wide area enables tracking of many targets, while the close-up view allows individuals to be identified from high-resolution images of their faces. A central component of a PTZ tracking system is a scheduling algorithm that determines which target to zoom in on, particularly when the high-resolution images are also used for tracklet matching. In this paper, we study this scheduling problem from a theoretical perspective. We propose a novel data structure, the Multi-strand Tracking Graph (MSG), which represents the set of tracklets computed by a tracker and the possible associations between them. The MSG allows efficient scheduling as well as resolving of matching ambiguities between tracklets. The main feature of the MSG is the auxiliary data saved in each vertex, which allows efficient computation while avoiding time-consuming graph traversal. Synthetic data simulations are used to evaluate our scheduling algorithm and to demonstrate its superiority over a naïve one.     

Increasing motorcycles attention and search conspicuity by using Alternating-Blinking Lights System (ABLS)

Poor conspicuity of Powered Two-Wheelers (PTW) is one of the main factors contributing to their involvement in accidents. The current study examined the influence of different rider's outfits on PTWs’ detectability, and evaluated the potential of a unique Alternating-Blinking Lights System (ABLS) to increase the rider's conspicuity. This study included two experiments that examined the visual search involved in the process of scanning video clips of dynamic traffic scenes. The first experiment examined PTWs’ attention conspicuity, while the second evaluated PTWs’ search conspicuity. In the attention conspicuity experiment participants were not alerted to the possible presence of a PTW and were asked to report the types of vehicles that were present in each video clip. In the search conspicuity experiment the participants were asked to actively search for a PTW and report its presence or absence in each video clip. Every participant was presented with a series of 96 video clips, 48 with a PTW and 48 without (controls). The independent variables were: (i) level of ambient illumination, (ii) road type, (iii) PTW's initial distance from the viewer, and (iv) rider's outfit. The results of the attention conspicuity experiment indicated that the environmental context has a strong effect on the probability of detecting the PTW. The ABLS increased the PTWs’ attention conspicuity by moderating the effects of environmental context, and was most effective at dusk and in urban environments. The results of the search experiment indicated that detection rates decreased and reaction time (RT) increased as the level of luminance decreased. RT was shortest with the ABLS across all driving environments. The ABLS increased PTWs detection rates in both experiments and mitigated the difference in detection rates between the attention and search conspicuity experiments. The results indicated that the ABLS was the most potent conspicuity treatment of the ones evaluated in this study. In conclusion, PTW conspicuity should be enhanced by incorporating aspects of both attention and search conspicuity. The riders need to take into consideration the perceptual characteristics of their riding environment, and be equipped with a conspicuity aid that is less susceptible to the changing environment and provides the rider with a unique visual signature. In parallel, the expectancy of car drivers to the presence of PTWs should be increased.     

A process mining-based analysis of business process work-arounds

Business process work-arounds are specific forms of incompliant behavior, where employees intentionally decide to deviate from the required procedures although they are aware of them. Detecting and understanding the work-arounds performed can guide organizations in redesigning and improving their processes and support systems. Existing process mining techniques for compliance checking and diagnosis of incompliant behavior rely on the available information in event logs and emphasize technological capabilities for analyzing this information. They do not distinguish intentional incompliance and do not address the sources of this behavior. In contrast, the paper builds on a list of generic types of work-arounds found in practice and explores whether and how they can be detected by process mining techniques. Results obtained for four work-around types in five real-life processes are reported. The remaining two types are not reflected in events logs and cannot be currently detected by process mining. The detected work-around data are further analyzed for identifying correlations between the frequency of specific work-around types and properties of the processes and of specific activities. The analysis results promote the understanding of work-around situations and sources.     

A Comparison of the Binding of the Ligand Trimethoprim to Bacterial and Vertebrate Dihydrofolate Reductases

In this paper, we report on studies of ligand binding to the enzyme dihydrofolate reductase (DHFR). Energy minimizations of four complexes of DHFR with the inhibitor trimethoprim, an antibiotic, and the cofactor NADPH have been carried out in order to investigate the energetics responsible for the 100,000-fold increase in binding affinity of trimethoprim to E. coli DHFR compared with chicken liver DHFR. Several factors suggested to be responsible for the enhanced binding in bacterial DHFR's were investigated in terms of intermolecular and intramolecular energetics. The strain energies of trimethoprim in the four complexes were calculated and found to be about 6 kcal mol⁻¹ in all complexes of the two species. In the binary complex of chicken liver DHFR, where the largest variation was observed, 2 kcal mol⁻¹ higher than in the other complexes, it was found that this increase was compensated for by the slightly more favorable intermolecular interaction of the trimethoxyphenyl moiety with the protein. Comparison of the minimized binary and ternary complexes of E. coli allowed us to investigate the cooperativity in the binding of trimethoprim and NADPH in the bacterial enzyme in terms of the underlying intermolecular forces. This cooperativity was found to be due to a direct trimethoprim - NADPH interaction in the E. coli enzyme rather than enhanced protein-inhibitor interactions induced upon binding of the cofactor. These interactions are not as favorable in the vertebrate enzyme, consistent with the significantly diminished cooperativity observed in this enzyme.     

Electron microscopy localization and characterization of functionalized composite organic-inorganic SERS nanoparticles on leukemia cells

We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic nanoparticle (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet scanning electron microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron (BSE) detector was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution transmission electron microscopy (TEM) images and scanning Auger electron spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens.