Association Between Adjuvant Chemotherapy and Nephrotoxicity and Kidney Function Monitoring in Elderly Breast Cancer Patients

University of Minnesota Ph.D. dissertation. May 2013. Major: Epidemiology. Advisor: Aaron Folsom. 1 computer file (PDF); viii, 130 pages.Background: Chronic kidney disease (CKD) and cancer are major public health problems in the elderly population. In elderly cancer patients, little is known about chemotherapy-related nephrotoxicity or patterns of CKD screening. The purpose of this dissertation was to evaluate the association between adjuvant chemotherapy (CHEMO) and risks of acute kidney injury (AKI) and CKD and rate of CKD screening in elderly women diagnosed with stages I-III breast cancer. Methods: The study was a 1:1 individually matched, retrospective cohort design using Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data. Matching was performed at the day of CHEMO initiation based on propensity score. The assembled matched cohorts were used in the analyses for all three objectives with different follow-up periods and statistical methods for each objective. HASH(0x307f974) Results: A total of 28,048 patients were included. CHEMO was associated with a 2.7-fold increased risk of AKI within 6 months after initiation (HR 2.7, 95% CI 1.8-4.1). To find a possible explanation to this association, the distribution of other diseases coded on hospital claims for AKI was examined and showed that septicemia occurred in 40% of CHEMO treated patients with AKI and in only 17% of untreated patients with AKI. No significant association was found between CHEMO and risk of CKD in the maximum 18 years follow-up (HR 1.00, 95% CI 0.93-1.07). The rate of CKD screening after treatment completion was low regardless of CHEMO status. HASH(0x2faf9d4) Conclusion: CHEMO is associated with increased risk of AKI. This association may be partially explained by septicemia caused by infection/neutropenia due to use of myelosuppressive chemotherapeutic agents, which highlights the importance of preventing serious complications of CHEMO in preventing AKI. The finding of no association between CHEMO and risk of CKD may not suggest a late nephrotoxic effect of chemotherapeutic agents commonly used to treat breast cancer in the adjuvant setting, or provide evidence to recommend a clinical practice guideline for CKD screening specifically in elderly breast cancer patients treated with CHEMO. Future studies of CKD as a late effect of cancer treatment for other solid tumors commonly treated with known or potential nephrotoxic agents are warranted

Opportunistic Wireless Control Over State-Dependent Fading Channels

The heterogeneous system consisting of the wireless control system (WCS) and mobile agent system (MAS) is ubiquitous in Industrial Internet of Things (IIoT) systems. Within this system, the positions of mobile agents may lead to shadow fading on the wireless channel that the WCS is controlled over and can significantly compromise the WCS's performance. This paper focuses on the controller design for the MAS to ensure the performance of WCS in the presence of WCS and MAS coupling. Firstly, the constrained finite field network (FFN) with profile-dependent switching topology is adopted to proceed the operational control for the MAS. By virtue of the algebraic state space representation (ASSR) method, an equivalent form is obtained for the WCS and MAS coupling. A necessary and sufficient condition in terms of constrained set stabilization is then established to ensure the Lyapunov-like performance with expected decay rate. Finally, a graphical method together with the breath-first searching is provided to design state feedback controllers for the MAS. With this method, it is easy to check the constrained set stabilization of MAS and to ensure the performance requirements of WCS in the presence of WCS and MAS coupling. The study of an illustrative example shows the effectiveness of the proposed method

A sensitive and rapid HPLC-DAD method for the determination of 3-hydroxy-1,2-dimethyl-4-pyridone and its distribution in rats

Purpose: To establish a sensitive and rapid method for the determination of the tissue distribution of 3-hydroxy-1,2-dimethyl-4-pyridone (L1) in vivo, and its plasma protein binding capacity.Methods: This study optimized a reverse-phase HPLC method for specific and sensitive determination of L1 as well as its plasma and tissue  distributions. The optimized method was used to determine the plasma protein-binding capacity of L1 in Wistar rats.Results: A rapid, sensitive and simple HPLC-DAD method was established for studying the plasma and tissue distribution of L1. Following TI  administration, its liver concentrations peaked at 60 min and 360min, followed 360 min later with peak level in the kidney (second highest). The L1 concentration was significantly lower after 360 min than after 60 min, and values of its mean binding to plasma proteins was 5.2 % at different L1 concentrations.Conclusion: These results indicate that L1 is a drug with rapid-absorption and rapid-elimination thath is distributed widely in vivo in rats. Moreover, the drug has a weak plasma protein-binding capacity. Keywords: 3-Hydroxy-1,2-dimethyl-4-pyridone, Distribution, Alzheimer’s disease, Therap

Pre-Peak Deformation and Damage Features of Sandstone under Cyclic Loading

In this paper, several sandstone specimens are prepared and subjected to uniaxial compression and cyclic loading. For each specimen, the loading segment of the stress-strain curve was fitted, and the peak slope of this segment was taken as the elastic modulus of the specimen in that cycle. It is learned that, under cyclic loading, the elastic modulus of each specimen increased with the growing number of load cycles, and tended to be stable; meanwhile, strain hardening was observed on all specimens. Moreover, the specimens are similar in corresponding stress, although varied in corresponding strain. In the same cycle, the tangent modulus of the loading phase was smaller than that of the unloading phase under the same stress. Finally, the damage variables of sandstone specimens under cyclic loading were defined from the angle of energy, revealing that the damage variables had logarithmic growth with the load cycles in the later stage

Hysteresis Characteristics of Brittle Rock Deformation under Constant Load Cyclic Loading and Unloading

This paper mainly explores the deformation characteristics of limestone specimens under constant load cyclic loading. For limestone specimens under uniaxial compression, the stress-strain curve can be divided into three stages: compaction stage, elastic stage and sudden failure stage. Under cyclic loading, the hysteresis loop on the stress-strain curve is long and thin, taking the shape of "toothpicks". The axial strain and radial strain both change with the stress amplitude and cycle number, but in different variation patterns. There is a stress amplitude "threshold" for radial deformation, indicating that the radial deformation is more sensitive to stress amplitude than the axial deformation. It is calculated that the incremental deformation between peaks includes both plastic deformation and the deformation recoverable after unloading, and the recoverable deformation is positively correlated with the load amplitude of the cyclic loading

MOTIVATIONS FOR CHOOSING TO STUDY TOURISM AND HOSPITALITY MANAGEMENT: A COMPARISON OF MAINLAND CHINESE AND TAIWANESE UNDERGRADUATE STUDENTS

More and more students choose Hospitality and Tourism Management (HTM) as their subject field in the universities and colleges in both Mainland China and Taiwan. The objective of this study was to investigate motivations of undergraduate students in choosing a HTM program for both Mainland China and Taiwan. The result of a factor analysis identified five factor domains for undergraduate students in both places. A cluster analysis produced four distinc-tive clusters for undergraduate students. Differences between Mainland Chinese and Taiwan-ese students were revealed in their motivations in choosing a HTM program, behaviors and attitudes toward HTM, and a socio-demographic variable. The study results hold useful impli-cations for educational researchers and for strategies for educational administrations in both Mainland China and Taiwan