1,036 research outputs found
Revisiting the Occupational Work Ethic Inventory: A Classical Item Analysis
Self-rated work attitudes of employees (N=492) from six randomly selected manufacturing companies were obtained using the Occupational Work Ethic Inventory (OWEI) (Petty, 1995b). Many respondents failed to answer the item with the descriptor apathetic or marked the highest level of response on a 1-7 Likert-type scale. The suitability of this item was investigated using a comparison of average inter-item correlations, comparison of item-scale correlations, and an internal consistency analysis. The item with the descriptor apathetic failed to demonstrate evidence to support its inclusion in the instrument. It was concluded that this item should be dropped from the scale and replaced by another item that is more readily understood by workers
Corrosion of Orthodontic Pliers Using Different Sterilization Procedures
Abstract : Aim: : The aim of this study was to investigate the corrosion resistance of orthodontic pliers from several manufacturers following different sterilization procedures, namely heat sterilization and the use of a disinfectant agent (Sekusept Extra N®) in an ultrasonic bath. Material and Methods: : Employed in this study were ten distal-end cutters and ten Weingart pliers manufactured by Aesculap®, ETM and Hu-Friedy®, examined under electron microscopy for evidence of corrosion following 500 sterilization cycles. The corrosion data were recorded photographically and graphically. Metallographic microsections were prepared from each pair of pliers and were then analyzed by means of EDX measurements to assess the chemical alloy composition. Results: : The light and electron microscopic evaluation showed that both heat sterilization and high level disinfection caused corrosive changes on the pliers. However, the type of corrosion differed between the two sterilization methods. The main type of corrosion with Sekusept Extra N® was pitting, while with heat sterilization it was surface corrosion. Heat sterilization was the type of corrosion that caused the most corrosive changes, regardless of which type of corrosion was considered. However, these results must be viewed critically, because pitting corrosion is obviously a more severe problem than surface corrosion. In comparing the pliers of various manufacturers, differences were noted. However, it was difficult to rank them when the correct maintenance regime was adhered to. The soldered joint gap was revealed to be a specific weak point, and that area proved to be inadequate due to qualities related to their production, particularly in the Hu-Friedy® pliers. Conclusions: : This study showed that heat sterilization leads to less corrosion than cold disinfection. Corroded pliers can be restored to a useable condition by re-polishing, though it is important that the instructions for their care be strictly adhered t
Theory, Simulation and Nanotechnological Applications of Adsorption on a Surface with Defects
Theory of adsorption on a surface with nanolocal defects is proposed. Two
efficacy parameters of surface modification for nanotechnological purposes are
introduced, where the modification is a creation of nanolocal artificial
defects. The first parameter corresponds to applications where it is necessary
to increase the concentration of certain particles on the modified surface. And
the second one corresponds to the pattern transfer with the help of particle
self-organization on the modified surface. The analytical expressions for both
parameters are derived with the help of the thermodynamic and the kinetic
approaches for two cases: jump diffusion and free motion of adsorbed particles
over the surface. The possibility of selective adsorption of molecules is shown
with the help of simulation of the adsorption of acetylene and benzene
molecules in the pits on the graphite surface. The process of particle
adsorption from the surface into the pit is theoretically studied by molecular
dynamic technique. Some possible nanotechnological applications of adsorption
on the surface with artificial defects are considered: fabrication of sensors
for trace molecule detection, separation of isomers, and pattern transfer.Comment: 12 pages, 2 Postscript figures. Submitted to Surface Science (1998
Protein interference applications in cellular and developmental biology using DARPins that recognize GFP and mCherry
Protein–protein interactions are crucial for cellular homeostasis and play important roles in the dynamic execution of biological processes. While antibodies represent a well-established tool to study protein interactions of extracellular domains and secreted proteins, as well as in fixed and permeabilized cells, they usually cannot be functionally expressed in the cytoplasm of living cells. Non-immunoglobulin protein-binding scaffolds have been identified that also function intracellularly and are now being engineered for synthetic biology applications. Here we used the Designed Ankyrin Repeat Protein (DARPin) scaffold to generate binders to fluorescent proteins and used them to modify biological systems directly at the protein level. DARPins binding to GFP or mCherry were selected by ribosome display. For GFP, binders with KD as low as 160 pM were obtained, while for mCherry the best affinity was 6 nM. We then verified in cell culture their specific binding in a complex cellular environment and found an affinity cut-off in the mid-nanomolar region, above which binding is no longer detectable in the cell. Next, their binding properties were employed to change the localization of the respective fluorescent proteins within cells. Finally, we performed experiments in Drosophila melanogaster and Danio rerio and utilized these DARPins to either degrade or delocalize fluorescently tagged fusion proteins in developing organisms, and to phenocopy loss-of-function mutations. Specific protein binders can thus be selected in vitro and used to reprogram developmental systems in vivo directly at the protein level, thereby bypassing some limitations of approaches that function at the DNA or the RNA level
The dynamics of replication licensing in live Caenorhabditis elegans embryos
Accurate DNA replication requires proper regulation of replication licensing, which entails loading MCM-2-7 onto replication origins. In this paper, we provide the first comprehensive view of replication licensing in vivo, using video microscopy of Caenorhabditis elegans embryos. As expected, MCM-2-7 loading in late M phase depended on the prereplicative complex (pre-RC) proteins: origin recognition complex (ORC), CDC-6, and CDT-1. However, many features we observed have not been described before: GFP-ORC-1 bound chromatin independently of ORC-2-5, and CDC-6 bound chromatin independently of ORC, whereas CDT-1 and MCM-2-7 DNA binding was interdependent. MCM-3 chromatin loading was irreversible, but CDC-6 and ORC turned over rapidly, consistent with ORC/CDC-6 loading multiple MCM-2-7 complexes. MCM-2-7 chromatin loading further reduced ORC and CDC-6 DNA binding. This dynamic behavior creates a feedback loop allowing ORC/CDC-6 to repeatedly load MCM-2-7 and distribute licensed origins along chromosomal DNA. During S phase, ORC and CDC-6 were excluded from nuclei, and DNA was overreplicated in export-defective cells. Thus, nucleocytoplasmic compartmentalization of licensing factors ensures that DNA replication occurs only once
Augmenting bispecific T-cell engager (BiTE) therapy for the treatment of Acute Myeloid Leukemia
United States Armed Forces' voluntary education program: The effect of enlisted service member retention
Thesis (Ph.D.) University of Alaska Fairbanks, 1997The United States Armed Forces have sponsored off-duty voluntary higher education programs for fifty years. The investment in these programs by the Armed Services is substantial. In 1996, Department of Defense (DOD) expenditures for Tuition Assistance programs totaled $121 million. The longevity and scope of these military programs make them an ideal special case through which to study the outcomes of employer sponsored off-duty education. This study looked at the relationship between participation in military sponsored off-duty education programs and enlisted retention in the service. The data for the study was from a large (60,000 respondents) survey conducted by the DOD in 1992. Both univariate and multi-variate statistical analysis techniques were used. Additionally, over thirty semi-structured interviews were conducted with service members. The quantitative analysis supports the conclusion that long-term participation in off-duty education is significantly and positively related to intention to reenlist in simple bi-variate models. However, when several other variables thought to be related to retention are controlled the overall education participation effect is very small, accounting for little of the variation in intention to reenlist. A comparison of the education participation pattern in this data with previous studies leads to the conclusion that there has been a fundamental change in the relationship between off-duty education and retention in the last ten to fifteen years. The qualitative data suggest that the military places a high value on educational participation exhibited in formal and informal policies, the organizational reward system, promotions and attitudes. The opportunity to participate varies by location, specific job and military specialty. Servicemembers' attitudes toward education appear to evolve. Early participation seems to be extrinsically motivated with an intrinsic motivation developing as the servicemember continues to participate. The quantitative and qualitative data support the conclusion that the military has changed in its view of educational participation. The data point to the conclusion that the military has adopted educational participation as an integral part of the military culture. This value is so embedded within the environment that the effect of educational participation may be masked by other variables such as satisfaction with the military way of life
Raman spectroscopy can discriminate between normal, dysplastic and cancerous oral mucosa: a tissue-engineering approach.
Head and neck cancer (HNC) is the sixth most common malignancy worldwide. Squamous cell carcinoma, the primary cause of HNC, evolves from normal epithelium through dysplasia before invading the connective tissue to form a carcinoma. However, less than 18% of suspicious oral lesions progress to cancer, with diagnosis currently relying on histopathological evaluation, which is invasive and time consuming. A non-invasive, real-time, point-of-care method could overcome these problems and facilitate regular screening. Raman spectroscopy is a non-invasive optical technique with the ability to extract molecular level information to help determine the functional groups present in a tissue and the molecular conformations of tissue constituents. In the present study, Raman spectroscopy was assessed for its ability to discriminate between normal, dysplastic and HNC. Tissue engineered models of normal, dysplastic and HNC were constructed using normal oral keratinocytes, dysplastic and HNC cell lines, and their biochemical content predicted by interpretation of spectral characteristics. Spectral differences were evident in both the fingerprint (600/cm to 1800/cm) and high wave-number compartments (2800/cm to 3400/cm). Visible differences were seen in peaks relating to lipid content (2881/cm), protein structure (amide I, amide III), several amino acids and nucleic acids (600/cm to 1003/cm). Multivariate data analysis algorithms successfully identified subtypes of dysplasia and cancer, suggesting that Raman spectroscopy not only has the potential to differentiate between normal, pre-malignant and cancerous tissue models but could also be sensitive enough to detect subtypes of dysplasia or cancer on the basis of their subcellular differences. Copyright © 2016 John Wiley & Sons, Ltd
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