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71.
Odom SA Jackson AC Prokup AM Chayanupatkul S Sottos NR White SR Moore JS 《ACS applied materials & interfaces》2011,3(12):4547-4551
We report a new core-shell microcapsule system for the visual detection of mechanical damage. The core material, 1,3,5,7-cyclooctatetraene, is a conjugated cyclic olefin and a precursor to intensely colored polyacetylene. A combination of poly(urea-formaldehyde) and polyurethane is required to effectively encapsulate the volatile core material. Increasing the outer shell wall thickness and including a core-side prepolymer improves the thermal stability and free-flowing nature of these capsules, which tend to leach and rupture with thinner shell walls. Capsules ruptured in the presence of the Grubbs-Love ruthenium catalyst show immediate color change from nearly colorless to red-orange and dark purple over time, and color change in thin films resulted from scratch damage. 相似文献
72.
White Kamila S.; Raffa Susan D.; Jakle Katherine R.; Stoddard Jill A.; Barlow David H.; Brown Timothy A.; Covino Nicholas A.; Ullman Edward; Gervino Eernest V. 《Canadian Metallurgical Quarterly》2008,76(3):422
The present study examined current and lifetime psychiatric morbidity, chest pain, and health care utilization in 229 patients with noncardiac chest pain (NCCP), angina-like pain in the absence of cardiac etiology. Diagnostic interview findings based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) revealed a psychiatrically heterogeneous sample of whom 44% had a current Axis I psychiatric disorder. A total of 41% were diagnosed with a current anxiety disorder, and 13% were diagnosed with a mood disorder. Overall, 75% of patients had an Axis I clinical or subclinical disorder. Lifetime diagnoses of anxiety (55%) and mood disorders (44%) were also prevalent, including major depressive disorder (41%), social phobia (25%), and panic disorder (22%). Patients with an Axis I disorder reported more frequent and more painful chest pain compared with those without an Axis I disorder. Presence of an Axis I disorder was associated with increased life interference and health care utilization. Findings reveal that varied DSM-IV Axis I psychiatric disorders are prevalent among patients with NCCP, and this psychiatric morbidity is associated with a less favorable NCCP presentation. Implications for early identification of psychiatric disorders are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
73.
74.
Tanya S. Hauck Robin E. Anderson Hans C. Fischer Susan Newbigging Warren C. W. Chan 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(1):138-144
Quantum dots have potential in biomedical applications, but concerns persist about their safety. Most toxicology data is derived from in vitro studies and may not reflect in vivo responses. Here, an initial systematic animal toxicity study of CdSe–ZnS core–shell quantum dots in healthy Sprague–Dawley rats is presented. Biodistribution, animal survival, animal mass, hematology, clinical biochemistry, and organ histology are characterized at different concentrations (2.5–15.0 nmol) over short‐term (<7 days) and long‐term (>80 days) periods. The results show that the quantum dot formulations do not cause appreciable toxicity even after their breakdown in vivo over time. To generalize the toxicity of quantum dots in vivo, further investigations are still required. Some of these investigations include the evaluation of quantum dot composition (e.g., PbS versus CdS), surface chemistry (e.g., functionalization with amines versus carboxylic acids), size (e.g., 2 versus 6 nm), and shape (e.g., spheres versus rods), as well as the effect of contaminants and their byproducts on biodistribution behavior and toxicity. Combining the results from all of these studies will eventually lead to a conclusion regarding the issue of quantum dot toxicity. 相似文献
75.
Field DJ Chandler DM 《Journal of the Optical Society of America. A, Optics, image science, and vision》2012,29(1):55-67
A wide variety of recent studies have argued that the human visual system provides an efficient means of processing the information in the natural environment. However, the amount of information (entropy) in the signal can be estimated in a number of ways, and it is has been unclear how much of the information is carried by the different sources of redundancy. The primary difficulty is that there has been no rational way to estimate the entropy of such complex scenes. In this paper, we provide a technique that uses a recent approach to estimating the entropy and dimensionality of natural scenes [D. M. Chandler and D. J. Field, J. Opt. Soc. Am. A 24, 922-941 (2007)] to estimate the amount of information attributable to the power and phase spectra in natural-scene patches. By comparing the entropies of patches that have swapped phase spectra and fixed phase spectra, we demonstrate how to estimate both the amount of information in each type of spectrum and the amount of information that is shared by these spectra (mutual information). We applied this technique to small patches (4×4 and 8×8). From our estimates, we show that the power spectrum of 8×8 patches carries approximately 54% of the total information, the phase spectrum carries 56%, and 10% is mutual information (54%+56%-10%=100%). This technique is currently limited to relatively small image patches, due to the number of patches currently in our collection (on the order of 10?). However, the technique can, in theory, be extended to larger images. Even with these relatively small patches, we discuss how these results can provide important insights into both compression techniques and efficient coding techniques that work with relatively small image patches (e.g., JPEG, sparse coding, independent components analysis). 相似文献
76.
We analyzed seven years of pre‐program and post‐program survey data to evaluate the Clarkson University Research Experience for Undergraduates (REU) Site Program in Environmental Science and Engineering, and evaluated whether our program was successful at meeting the intended outcome of increasing participants' likelihood of attending graduate school and pursuing a career in science or engineering research or education. We also evaluated how participant satisfaction in the program changed with the addition of a weekly seminar on environmental sustainability that was intended to improve participants' understanding of the societal value of their research projects. Participant satisfaction in the Clarkson REU Program was high, and increased after the addition of the sustainability seminar. Participants' intention to attend graduate or professional school increased after participating in the program, but their intention to pursue a career in science or engineering research declined. Over 60 percent of participants eventually attended graduate or professional school. 相似文献
77.
Nearly one‐half of the industrial engineering undergraduate interviewees in an investigation of their degree program indicated they previously had been enrolled in another major. Understanding why these students chose to remain in or enter a science, technology, engineering and math (STEM) major when their previous choice lost its appeal is an important piece of the STEM participation puzzle. Our data indicate effective formal and informal recruiting, contact with dynamic individuals who conveyed commitment to and excitement about the department and program, and a department that welcomed immigrants and promoted a clear, relevant image of its discipline's identity, influenced student decisions to relocate within STEM rather than attrite. The high proportion of females within the immigrant students is one factor contributing to the department's attainment of sex parity. Our students' stories offer lessons to other departments for attracting and retaining students who enter the higher education STEM pipeline. 相似文献
78.
This paper discusses how group size and project duration impact capstone design in terms of learning objectives for the student, value to industry sponsors, and faculty resources. The analysis is based on survey results and an external faculty evaluation comparing a one‐semester offering with a two‐semester offering of capstone design in the School of Industrial and Systems Engineering at the Georgia Institute of Technology. In addition, we examine whether the stated learning objectives (technical writing skills, presentation skills, and technical analysis) for the course provide value to sponsors. Our findings suggest that the one‐semester offering was preferred by both students and industry sponsors and required fewer resources. We also found that although students prefer smaller group sizes, sponsors do not have a definitive preference. Finally, we found that although technical analysis is significantly correlated with dollar value to the sponsor, technical writing skills and presentation skills were not. 相似文献
79.
Small lesions of the dorsomedial amygdala reduced the magnitude of the conditioned place aversion produced by naltrexone-precipitated morphine withdrawal, whereas large lesions of the ventral nucleus accumbens had no effect. This finding that the dorsomedial amygdala, which has not been implicated in opiate reward, is involved in mediating the aversiveness of opiate withdrawal is consistent with data indicating that amygdala lesions reduce the aversiveness of a variety of aversive events. In contrast, the nucleus accumbens, which is involved in mediating the rewarding effects of opiates, does not appear to be critically involved in mediating the aversive effects of opiate withdrawal. Together, these findings suggest that the neural structures that mediate the rewarding effects of opiates may be at least partially distinct from the structures that mediate the aversive effects of opiate withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
Harrison Patti L.; Cummings Jack A.; Dawson Margaret; Short Rick J.; Gorin Susan; Palomares Ron 《Canadian Metallurgical Quarterly》2003,18(4):358
The preparations for and the implementation of the 2002 Multisite Conference on the Future of School Psychology are described. The conference goals were to (a) achieve consensus on current and future demands for school psychologists and our profession's ability to meet those demands; (b) conceptualize the practice of school psychology in the face of diminishing numbers and increasing demand for services; and (c) develop an agenda to use the resources we have to maximize the benefits to the children and schools that we serve. A problem-solving model served as the conceptual foundation of the conference. School psychologists at the host site in Indianapolis and 30 remote sites collaborated to identify threats, opportunities, strategies, and action plans to respond better to the needs of children, families and schools. The conference not only generated excitement and hope for our future, but also provided a framework to propel the current and future practice of school psychology. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献