324 research outputs found
Osteopontin and `Melanoma Inhibitory Activity': Comparison of Two Serological Tumor Markers in Metastatic Uveal Melanoma Patients
Background: Evaluation of the protein osteopontin (OPN) as a potential new marker in comparison to melanoma inhibitory activity (MIA) for screening and detection of metastatic uveal melanoma. Methods: Plasma levels of 32 patients with uveal melanoma were analyzed for OPN and MIA by enzyme-linked immunosorbent assay (ELISA). Fourteen of these patients had clinically detectable liver metastases. Results: Median plasma concentration of OPN in patients with metastatic disease was 152.01 ng/ml compared to 47.39 ng/ml in patients without clinically detectable metastases (p < 0.001). The difference between the median MIA plasma levels in patients with (13.11 ng/ml) and patients without (5.64 ng/ml) metastatic disease was also statistically significant (p < 0.001). No correlation could be found between MIA or OPN levels and tumor height in patients without clinically detectable metastases. Conclusion: The proteins MIA and OPN seem to be promising tumor markers for the metastasis screening in patients with uveal melanoma. Copyright (C) 2009 S. Karger AG, Base
GOOD, BAD, OR BOTH? MEASUREMENT OF PHYSICIAN’S AMBIVALENT ATTITUDES TOWARDS AI
Artificial intelligence is currently one of the most controversial discussed technologies across various work domains. In healthcare, AI fosters widespread positive beliefs of substantially increasing the quality of care, yet evoking physicians’ fears of being marginalized or replaced. The described controversy leads to ambivalent attitudes, as physicians hold both strong positive and negative evaluations at the same time. However, current research in information systems has not been able to measure ambivalence because uni-polar attitude scales cannot assess this construct. Additionally, it is unclear whether ambivalence has positive or negative consequences and how it is related to resistance to change. In the context of AI in healthcare, we conducted a survey study (n=74) to measure context-specific attitudes and attitude ambivalence of physicians. We distinguish between two states of ambivalence and show that physicians who experience an inner conflict (Felt Ambivalence) from conflicting attitudes (Potential Ambivalence) develop resistance to change. Moreover, including ambivalence into a regression model explains more variance than uni-polar attitudes alone. With this research, we show that ambivalent attitudes can be measured in the context of technological change. Additionally, we explore how context-specific attitudes towards AI in healthcare drive physicians’ ambivalence towards it
An X-ray Microscopy Study of the Microstructural Effects on Thermal Conductivity in Cast Aluminum-Copper Compounds
A metallurgical joint between aluminum and copper established by compound casting provides for high thermal conductivity, which is required for lightweight cooling solutions in applications such as high-power light-emitting diodes or computer processors. If casting is employed in a silane-doped inert gas atmosphere whose oxygen partial pressure is adequate to extreme high vacuum, reoxidation of the active surfaces of aluminum and copper is prevented, and thus a metallurgical bond can be created directly between aluminum and copper. With this approach, thermal conductivities as high as 88.3 W/m·K were realized. In addition, X-ray microscopy was used to shed light on the microstructure–thermal property relationship. It is demonstrated that both porosity and non-bonded areas have a substantial impact on the thermophysical properties of the compound zone. Based on the data obtained, casting parameters can be developed that provide for defect-free bonding zones and optimal heat transfer between the joining partners
Cu-Ni-Based Alloys from Nanopowders as Potent Thermoelectric Materials for High-Power Output Applications
A new approach for the development of thermoelectric materials, which focuses on a high-power factor instead of a large figure of merit zT, has drawn attention in recent years. In this context, the thermoelectric properties of Cu-Ni-based alloys with a very high electrical conductivity, a moderate Seebeck coefficient, and therefore a high power factor are presented as promising low-cost alternative materials for applications aiming to have a high electrical power output. The Cu-Ni-based alloys are prepared via an arc melting process of metallic nanopowders. The heavy elements tin and tungsten are chosen for alloying to further improve the power factor while simultaneously reducing the high thermal conductivity of the resulting metal alloy, which also has a positive effect on the zT value. Overall, the samples prepared with low amounts of Sn and W show an increase in the power factor and figure of merit zT compared to the pure Cu-Ni alloy. These results demonstrate the potential of these often overlooked metal alloys and the utilization of nanopowders for thermoelectric energy conversion
Oxygen-Free Compound Casting of Aluminum and Copper in a Silane-Doped Inert Gas Atmosphere: A New Approach to Increase Thermal Conductivity
Novel aluminum-copper compound castings devoid of oxide layers at the interface between the joining partners were developed in order to increase the thermal conductivity of the hybrid component. Due to the natural oxide layers of both aluminum and copper, metallurgical bonds between such bi-metal castings cannot be easily achieved in conventional processes. However, in an atmosphere comparable to extreme high vacuum created by using silane-doped inert gas, metallurgical bonds between the active surfaces of both aluminum and copper can be realized without additional coatings or fluxes. An intermetallic was created between aluminum and copper. Thus, very high thermal conductivities could be obtained for these hybrid castings, exceeding those of conventionally joined samples considerably. The intermetallic phase seams emerging between the joining partners were investigated using scanning electron microscopy and X-ray diffraction. The reduction of casting temperatures resulted in narrower intermetallic phase seams and these in turn in a much lower contact resistance between the two joining partners. This effect can be utilized for increasing the heat transfer capabilities of compound casting components employed for cooling heat sources such as high-power light-emitting diodes
Vitamin D Deficiency in Adult Patients with Schizophreniform and Autism Spectrum Syndromes: A One-Year Cohort Study at a German Tertiary Care Hospital
Introduction: Vitamin D has many immunomodulatory, anti-inflammatory, and neuroprotective functions, and previous studies have demonstrated an association between vitamin D deficiency and neuropsychiatric disease. The aim of our study was to analyze the prevalence of vitamin D deficiency in a one-year cohort of adult inpatients with schizophreniform and autism-spectrum syndromes in a naturalistic in-patient setting in Germany. Participants and methods: Our study was comprised of 60 adult schizophreniform and 23 adult high-functioning autism spectrum patients who were hospitalized Page: 2between January and December of 2015. We compared our findings with a historical German reference cohort of 3,917 adults using Pearson’s two-sided chi-squared test. The laboratory measurements of 25-hydroxyvitamin D2/3 (25(OH)vitamin D) were obtained using a chemiluminescence immunoassay. Results: In the schizophreniform group, we found decreased ( 30 ng/ml were observed in only 5% of the schizophreniform patients, 8.7% of the autism spectrum patients, and 21.9% of the healthy controls. Discussion: We found very high rates of 25(OH)vitamin D deficiency in both patient groups, and have discussed whether our findings might be related to alterations in the immunological mechanisms. Irrespective of the possible pathophysiological links between vitamin D deficiency and schizophrenia or autism spectrum disorders, a more frequent measurement of vitamin D levels seems to be justified in these patient groups. Further prospective, controlled, blinded, and randomized research should be conducted to analyze the effectiveness of vitamin D supplementation on the improvement of psychiatric symptoms
Structure elucidation and toxicological evaluation of cyclic Polyethersulfone oligomers present in extracts of membrane filters
Polyethersulfone (PES) is a widely used polymer in consumer and technical products. An important application is PES membranes used in the biopharmaceutical industry for sterilizing-grade filtration and for filtration of food and beverages. For both uses, detailed information about migrating compounds that can be extracted from the polymeric material into a liquid must be gathered. In the pharmaceutical industry, comprehensive extractables studies are required for contact materials, and the data is used in the qualification of the process equipment. PES is generated via polycondensation, which forms cyclic oligomers as a by-product of the reaction. However, no structural information is available for these cyclic oligomers so far. In this publication, we present the analytical determination of PES cyclic oligomers. Their presence in extracts of PES membrane filters is confirmed. The structure of the PES cyclic trimer is elucidated by X-ray and NMR investigation, obtained as crystals from the sublimation of the PES raw material. A strategy is shown to assess the toxicity of such cyclic oligomers and to derive a permitted daily exposure (PDE). The data will reduce the levels of unknowns in extractables and leachables screenings and supports the risk assessment of PES sterile filters
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