33 research outputs found
Accurate determination of interface trap state parameters by admittance spectroscopy in the presence of a Schottky barrier contact: Application to ZnO-based solar cells
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Marin, A. T., Musselman, K. P., & MacManus-Driscoll, J. L. (2013). Accurate determination of interface trap state parameters by admittance spectroscopy in the presence of a Schottky barrier contact: Application to ZnO-based solar cells. Journal of Applied Physics, 113(14), 144502 and may be found at https://doi.org/10.1063/1.4799633This work shows that when a Schottky barrier is present in a photovoltaic device, such as in a device with an ITO/ZnO contact, equivalent circuit analysis must be performed with admittance spectroscopy to accurately determine the pn junction interface recombination parameters (i.e., capture cross section and density of trap states). Without equivalent circuit analysis, a Schottky barrier can produce an error of similar to 4-orders of magnitude in the capture cross section and similar to 50% error in the measured density of trap states. Using a solution processed ZnO/Cu2O photovoltaic test system, we apply our analysis to clearly separate the contributions of interface states at the pn junction from the Schottky barrier at the ITO/ZnO contact so that the interface state recombination parameters can be accurately characterized. This work is widely applicable to the multitude of photovoltaic devices, which use ZnO adjacent to ITO.International Copper AssociationERC for the Advanced Investigator Grant, Novox [ERC-2009-adG 247276]Gates Cambridge TrustGirton College (Cambridge
Can text-search methods of pathology reports accurately identify patients with rectal cancer in large administrative databases?
No full textBackground: The aim of this study is to derive and to validate a cohort of rectal cancer surgical patients within administrative datasets using text-search analysis of pathology reports. Materials and Methods: A text-search algorithm was developed and validated on pathology reports from 694 known rectal cancers, 1000 known colon cancers, and 1000 noncolorectal specimens. The algorithm was applied to all pathology reports available within the Ottawa Hospital Data Warehouse from 1996 to 2010. Identified pathology reports were validated as rectal cancer specimens through manual chart review. Sensitivity, specificity, and positive predictive value (PPV) of the text-search methodology were calculated. Results: In the derivation cohort of pathology reports (n = 2694), the text-search algorithm had a sensitivity and specificity of 100% and 98.6%, respectively. When this algorithm was applied to all pathology reports from 1996 to 2010 (n = 284,032), 5588 pathology reports were identified as consistent with rectal cancer. Medical record review determined that 4550 patients did not have rectal cancer, leaving a final cohort of 1038 rectal cancer patients. Sensitivity and specificity of the text-search algorithm were 100% and 98.4%, respectively. PPV of the algorithm was 18.6%. Conclusions: Text-search methodology is a feasible way to identify all rectal cancer surgery patients through administrative datasets with high sensitivity and specificity. However, in the presence of a low pretest probability, text-search methods must be combined with a validation method, such as manual chart review, to be a viable approach
The application of localized surface plasmons resonance in Ag nanoparticles assisted Si chemical etching
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Ding, R., Dai, H., Li, M., Huang, J., Li, Y., Trevor, M., & Musselman, K. P. (2014). The application of localized surface plasmons resonance in Ag nanoparticles assisted Si chemical etching. Applied Physics Letters, 104(1), 011602 and may be found at https://doi.org/10.1063/1.4855615Localized surface plasmons excited by Ag nanoparticles are introduced in the chemical etching process of silicon. A special crateriform structure with gradually varying radius is achieved by the surface electromagnetic field enhancement effect of localized surface plasmons resonance (LSPR). Theoretical analysis demonstrates that the formation kinetics of the crateriform structures conforms to the local electromagnetic field enhancement and forward scattering induced by LSPR. The LSPR assisted photocatalytic etching offers a potential approach for the preparation of the surface microstructures used in optoelectronic devices.National Natural Science Foundation of China [91333122, 51372082, 51172069, 50972032, 61204064, 51202067]Ph.D. Programs Foundation of Ministry of Education of China [20130036110012, 20110036110006]Fundamental Research Funds for the Central Universities [11ZG02
Simple plasma assisted atomic layer deposition technique for high substitutional nitrogen doping of TiO2
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Alshehri, A. H., Nelson-Fitzpatrick, N., Ibrahim, K. H., Mistry, K., Yavuz, M., & Musselman, K. P. (2018). Simple plasma assisted atomic layer deposition technique for high substitutional nitrogen doping of TiO2. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 36(3), 031602 and may be found at https://doi.org/10.1116/1.5019170In this work, a plasma assisted atomic layer deposition system was used to deposit nitrogen-doped titanium dioxide. A simple approach was developed that requires only a nitrogen plasma and short plasma exposure times to effectively dope TiO2. A range of nitrogen concentrations were achieved by varying the flow rate and exposure times of nitrogen and oxygen plasmas. A nitrogen content as high as 23 ± 0.5 at. % was observed when only the nitrogen plasma was used. It was also possible to vary the type of nitrogen doping from almost entirely interstitial to purely substitutional, as measured by x-ray photoelectron spectroscopy. Ultraviolet-visible spectroscopy measurements showed a shifting in the absorption edge from 350 to 520 nm with doping, indicating bandgap narrowing from 3.1 to 1.9 eV.Canada Foundation for InnovationOntario Ministry of Research and Innovation, Industry, CanadaMike and Ophelia Lazaradi
Should lymph node retrieval be a surgical quality indicator in colon cancer?
No full text 648 Background: Adequate lymph node harvest is easily obtained and is necessary for proper staging of colorectal cancer, making it an attractive measure of surgical quality for policy makers. However, achieving an adequate lymph node harvest requires a multidisciplinary effort. The purpose of this study was to determine if it is appropriate to use this measure as a surgical quality indicator for individual surgeons. Methods: The study was undertaken at a high volume center with standardized colon cancer specimen processes. The charts of 1,138 consecutive segmental colon cancer surgeries performed between 2002 and 2008 were retrospectively analyzed. The primary outcome was inadequate lymph node retrieval for colon cancer surgery defined by fewer than 12 lymph nodes on pathology. Predictor variables were based on patient, surgeon, pathology and tumor related factors. Univariate analysis was performed on all potential predictor variables, followed by multivariate logistic regression. Results: 841 cases (69.0%) achieved adequate lymph node harvest, while 377 (31.0%) were inadequate. Factors on univariate analysis associated with inadequate lymph node harvest were specimen length (p<0.0001), tumor location (p<0.0001), and T-stage (0.0015), all of which remained significant multivariate logistic regression. The average specimen length differed by 3.6 cm between non-adequate and adequate specimens. When broken down by procedure, resection length did not vary significantly between high and low volume surgeons or between colorectal and non-colorectal surgeons. Furthermore when surgeons were ranked according to their success rate of >12 LN retrieval, there was no difference between surgeons in mean specimen length. Conclusions: In a high-volume, tertiary care centre that uses standardized practices for specimen processing, 31% of cases yielded fewer than 12 lymph nodes. Factors relating to the patient and tumor were the primary predictors of a successful outcome and there was no association between surgeon-related factor and adequate LN retrieval. Caution should be used when considering LN harvest as a surgical quality indicator for individual surgeons. </jats:p
Simulated electron affinity tuning in metal-insulator-metal (MIM) diodes
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in J. Appl. Phys. and may be found at http://dx.doi.org/10.1063/1.4983256.Metal-insulator-metal diodes for rectification applications must exhibit high asymmetry, nonlinearity, and responsivity. Traditional methods of improving these figures of merit have consisted of increasing insulator thickness, adding multiple insulator layers, and utilizing a variety of metal contact combinations. However, these methods have come with the price of increasing the diode resistance and ultimately limiting the operating frequency to well below the terahertz regime. In this work, an Airy Function Transfer Matrix simulation method was used to observe the effect of tuning the electron affinity of the insulator as a technique to decrease the diode resistance. It was shown that a small increase in electron affinity can result in a resistance decrease in upwards of five orders of magnitude, corresponding to an increase in operating frequency on the same order. Electron affinity tuning has a minimal effect on the diode figures of merit, where asymmetry improves or remains unaffected and slight decreases in nonlinearity and responsivity are likely to be greatly outweighed by the improved operating frequency of the diode
Evaluation of an evidence based educational module on glycemic control of targeted temperature management patients in the critical care setting
No full textPurpose of Project: After review of the glycemic control of patients undergoing targeted temperature management (TTM) after cardiac arrest at a New Jersey hospital, data revealed that patients remained in a hyperglycemic state (Glucose >180 mg/dL) for more than 24 hours post initiation of TTM. The purpose of this quality improvement project was to improve upon the glycemic control of TTM patients through the use of an educational module emphasizing the importance and rationale behind glycemic management.
Methodology: Education was provided to the nursing staff who was responsible for the care of these TTM patients regarding the rationale behind glycemic control and current guidelines. Participants took part in a mandatory online education module made available via the hospitals online learning management system. Participants were required to review the online module and answer 10 questions reviewing the material at the end of the presentation. To successfully complete the module, all questions had to be answered correctly with a score of 100 percent. Data was collected through retrospective and prospective chart reviews of TTM patients prior to and after the education module was provided to the critical care and ED staff nurses. Data collected included age, gender, average glucose between zero and 24 hours, and confounding variables including medications mixed in dextrose, corticosteroids use, pressor use and previous diabetes diagnosis.
Results: An unpaired t- test was run comparing the mean glycemic values at 12 hours and 24 hours. Using an alpha value of 0.05 it was determined that there was no statistical significance between average glycemic values of TTM patients at 12 hours before education (M: 210.67 mg/dL, SD: 72) and after education (M: 202 mg/dL, SD: 72); (t= 0.263, P=0.79). It was also determined that at 24 hours, there was no statistical difference between the pre education group of TTM patients (M: 191.96 mg/dL, SD: 75.19) and the post education group of TTM patients (M: 208.5 mg/dL, SD: 70.5); (t= 0.603, P: 0.55) and in fact the mean at 24 hours increased after education Using SPSS, a Pearson product- moment correlation was run to determine if any relationship existed between the mean glucose values of the TTM patients and the use of intravenous insulin (r=-.314, n=37, p=.058), the use of corticosteroids (r=-469, n= 37, P= .003), the use of vasopressors (r=-.062, n= 37, P=0.714), the number of vasopressors (r=-.058, n= 37, P=0.732), use of continuous dextrose infusions (r=-.124, n=37, P= 0.465) and previous diagnosis of diabetes (r=-.616, n=37, P= <0.001).
Implications for Practice: Quality improvement is trying to constantly improve upon the way we care for patients, the constant need to provide the best, evidence based care. This project was an attempt at improving the care of this patient population. Based on the results, we can do better. This project may have been the first step in improving the glycemic control of TTM patients using the Plan, Do Study Act framework. As mentioned, this framework is based on a continuum, a constant circle to continuously improve the care that is provided. Based on the results of this project, we can still strive to improve the quality of care that we provide and improve the glycemic control of these patients.DNPIncludes bibliographical reference
Can Text-Search Methods of Pathology Reports Accurately Identify Patients with Rectal Cancer in Large Administrative Databases?
No full text(In)Consistencies in responses to sodium bicarbonate supplementation: a randomised, repeated measures, counterbalanced and double-blind study
No full textObjectives:
Intervention studies do not account for high within-individual variation potentially compromising the magnitude of an effect. Repeat administration of a treatment allows quantification of individual responses and determination of the consistency of responses. We determined the consistency of metabolic and exercise responses following repeated administration of sodium bicarbonate (SB).
Design and Methods:
15 physically active males (age 25 ± 4 y; body mass 76.0 ± 7.3 kg; height 1.77 ± 0.05 m) completed six cycling capacity tests at 110% of maximum power output (CCT 110% ) following ingestion of either 0.3 g.kg -1 BM of SB (4 trials) or placebo (PL, 2 trials). Blood pH, bicarbonate, base excess and lactate were determined at baseline, pre-exercise, post-exercise and 5-min post-exercise. Total work done (TWD) was recorded as the exercise outcome.
Results:
SB supplementation increased blood pH, bicarbonate and base excess prior to every trial (all p ≤0.001); absolute changes in pH, bicarbonate and base excess from baseline to pre-exercise were similar in all SB trials (all p > 0.05). Blood lactate was elevated following exercise in all trials (p ≤ 0.001), and was higher in some, but not all, SB trials compared to PL. TWD was not significantly improved with SB vs. PL in any trial (SB1: +3.6%; SB2 +0.3%; SB3: +2.1%; SB4: +6.7%; all p > 0.05), although magnitude-based inferences suggested a 93% likely improvement in SB4. Individual analysis showed ten participants improved in at least one SB trial above the normal variation of the test although five improved in none.
Conclusions:
The mechanism for improved exercise with SB was consistently in place prior to exercise, although this only resulted in a likely improvement in one trial. SB does not consistently improve high intensity cycling capacity, with results suggesting that caution should be taken when interpreting the results from single trials as to the efficacy of SB supplementation.
Trial Registration:
ClinicalTrials.gov NCT0247462
Factors influencing engagement in physical activity among female Chinese American college students
No full textDespite the known short and long term benefits of physical activity, participation in moderate-to-vigorous physical activity continues to decline throughout the lifespan. Female Asian college students have been shown to be the least physically active of all college students, yet there is limited research of Asian ethnic subgroups. The purpose of this study was to examine the relationship between acculturation, microaggression, social norms, and socioeconomic status and engagement in physical activity among female Chinese American college students. A total of 203 female Chinese American students attending college in the San Francisco Bay area participated in the study. Participants completed a demographic questionnaire and four additional online surveys measuring the study variables. The majority of study participants (78.3%) reported being physically active at levels to obtain health benefits. This entails engaging in moderate physical activity for at least 30 minutes on 5 or more days each week. The expectation of significant others, such as parents and friends, to be physically active was found to be significantly correlated to engagement in physical activity (r = .28, p = .000). Socioeconomic status was also positively correlated with engagement in physical activity (r = .14, p = .047). Together these variables accounted for 12% of the variance in the sample, although expectations of significant others (social norms) explained 10% of the variance. Study findings have many implications for future research and practice. Social norms and socioeconomic status only explained a small amount of the variance in physical activity. College professors are in a position to be more involved in promoting physical activity and additional factors influencing engagement in physical activity among college students should be explored. The female Chinese American college students were found to be less physically active as they get older and progressed through the college years. Although the association did not reach significance, it is important to understand factors influencing participation in PA and reasons for the decline in PA. The college setting is ideal for culturally effective intervention efforts promoting PA as a healthy lifestyle behavior.Ph. D.Includes bibliographical referencesIncludes vitaby Elaine A. Musselma
