Identifying High Crash Risk Roadways through Jerk-Cluster Analysis

The state-of-the-practice for most municipal traffic agencies seeking to identify high-risk road segments has been to use prior crash history. While historic traffic crash data is recognized to be valuable in improving roadway safety, it relies on prior observation rather than future crash likelihood. Recently, however, researchers are developing predictive crash methods based on “abnormal driving events.” These include abrupt and atypical vehicle movements thought to be indicative of crash avoidance maneuvers and/or near-crashes. Because these types of near-crash events occur far more frequently than actual crashes, it is hypothesized that they can be used as an indicator of high-risk locations and, even more valuably, to identify where crashes are likely to occur in the future. This thesis describes the results of research that used naturalistic driving data collected from global positioning system (GPS) sensors to locate high concentrations of abrupt and atypical vehicle movements in Baton Rouge, Louisiana based on vehicle rate of change of acceleration (jerk). Statistical analyses revealed that clusters of high magnitude jerk events while decelerating were significantly correlated to long-term crash rates at these same locations. These significant and consistent relationships between jerks and crashes suggest that these events can be used as surrogate measures of safety and as a way of predicting safety problems before even a single crash has occurred

Molecules assembling and reacting under the constraint of weak and strong surface interactions

On surface chemistry and physics of nanoscale molecular self-assemblies manufactured in a “bottom-up” approach is the base on which this thesis is established. The formation of the mentioned self-assemblies is dependent on the interactions between their organic molecular building blocks and building blocks-substrate interaction. These organic molecules are synthesized for specific purposes by modifying molecular topology, structure and functional groups. The substrates employed are predominantly single crystals composed of coinage metals or single crystals with deposited adlayers. Chemical modification of these compounds via different bonding motifs (i.e. Hydrogen bonding, coordination, Van der Waals interaction, etc) in their self-assemblies is studied after their in-situ deposition using Scanning Tunneling Microscopy (STM), X-ray photoelectron spectroscopy (XPS) and Density Functional Theory (DFT). In chapter [[1]] direct comparison between in-solution and on-surface behavior of the same compounds is presented. Synthesis and surface assembly of the higher pyrazinacenes and their oxidized analogues using PbO2 in solution and annealing on Cu(111) substrate is studied. Upon thermal deposition of these compounds on single Cu(111) crystal, the molecules arrange in a chiral conformation. Subsequent annealing at 150 °C causes the dehydrogenation of the molecules and consequently the formation of linear arrays. Further annealing to 300 °C breaks the linear chains and the molecules appear to adopt a “double-lobe” or “two dark satellite” morphology which we attribute to further oxidation (cyclodehydrogenation). In chapter [[2]] the unprecedented ‘out-of-plane’ oriented, hydrogen-bonded assemblies of a planar module, the perylene derivative DPDI on a specifically-chosen weakly interacting substrate is studied. A single atomic layer of semi-metallic Bi in p(10x10) phase is selected as the substrate as it is known to be electronically decoupled from the underlying metallic Cu(100) single crystal thus can be used to study mainly intermolecular interactions. Extended, hexagonal networks containing “windmill-shaped” nodes with unique bi-chirality features, together with a compact assembly of zigzag structures are the two spontaneously formed supramolecular structures which are of great chemical importance since direct deposition of DPDI on Cu(100) does not lead to any sort of assembly. In chapter [[3]] the self-assembly of functionalized tetraphenylporphyrins in different architectures is presented. Trifluoromethyl and methoxy- functionalized tetraphenylporphyrins were synthesized and used to reveal polymorphism, driven by F…F interactions and C-F…H-C hydrogen bonds. The on-surface behavior of the symmetric and asymmetric functionalized compounds (trans and mono, respectively) is compared with tetrakis(3,4,5-trimethoxyphenyl)- and tetrakis(3,5-trifluoromethylphenyl)-porphyrins

Improving the Performance of Electroanalytical Devices for Sensing and Energy Storage

University of Minnesota Ph.D. dissertation. January 2016. Major: Chemistry. Advisor: Philippe Buhlmann. 1 computer file (PDF); xxvii, 334 pages.My graduate research was focused on improving the performance and expanding the application of two categories electrochemical devices that are used in energy storage and sensing: electrochemical double-layer capacitors and ion-selective electrodes. The energy density of an electrochemical capacitor is determined by ½ CV2, where V is the potential difference between the plates of a capacitor and C is the capacitance density. Therefore, extending the operational voltage of such devices, which is limited by the electrochemical window of the electrolyte, can improve the device energy density. Optimizing the structure and improving electrochemical stability of electrolytes that can be utilized in electrochemical capacitors, was one of the goals of research presented in this thesis. Chapter 2 reviews the conventional methods for quantifying the electrochemical stability of electrolytes, and discusses their limitations. A new method for quantifying electrochemical stability of ionic liquids and electrolytes is suggested and several advantages of the proposed method is demonstrated for variety of systems. The effect of electrolyte structure on its electrochemical stability and accessible potential window is discussed in Chapter 3 and Chapter 4 highlights advantages of application of ionic liquids as electrolytes in electrochemical capacitors. Ion-selective electrodes, ISEs, are electrochemical sensors that determine the concentration of a wide range of ions and are used for billions of measurements in clinical, environmental, and chemical process analyses every year. However, two factors limit the application of ISEs in biological analyses: (1) Interference of biological molecules (2) Large sample volumes needed for ISE measurements. Recently, fluorophilic compounds have been applied in the ion-selective membrane of ISEs in an effort to reduce the interference of biological molecules. Chapters 5 to 7 show the reliability of sensing with fluorous-phase ion-selective electrodes in the environmental and biological samples. A part of my thesis research is focused on reducing the sample volume needed for detection with these sensors. This goal was achieved by development of highly fluorophilic electrolytes which were used to decrease the resistivity of the fluorous sensing membranes, allowing fabrication of fluorous-phase µ-ISEs and significantly decreasing the sample volume required for sensing

Investigation of the presence of G354A (Cys87Tyr) mutation in osteoprotegerin gene in women with osteoporosis in Chaharmahal and Bakhtiari province

Background and aims: Osteoprotegerin (OPG) is a competitive inhibitor of the differentiation and activity of osteoclasts, which inhibits the final stages of osteoclast formation and induces its apoptosis. In addition, OPG is considered as one of the most important candidate genes in the pathogenesis of bone diseases such as osteoporosis and idiopathic hyperphosphatasia. The G354A (Cys87Tyr) mutation in the OPG gene leads to idiopathic hyperphosphatasia. This mutation is probably related to osteoporosis. The purpose of this study was to investigate the presence of G354A (Cys87Tyr) in women with osteoporosis in Chaharmahal and Bakhtiari province. Methods: In this descriptive-analytical study, the bone mineral density (BMD) of the femoral neck and lumbar spine of women referring to Shahrekord bone densitometry centers was measured by the X-ray absorptiometry technique in 2013-2014. Based on T-scores, people with osteoporosis were identified and 70 patients were enrolled in the study after receiving their consent. Finally, DNA was extracted from blood samples, amplified by polymerase chain reaction (PCR) technique, and sequenced by DNA sequencing method. Results: After DNA extraction from the blood, the quality and quantity were determined by gel electrophoresis and spectrophotometry, respectively. Then, the gene was amplified by the PCR method and the product was detected by gel electrophoresis, followed by sequencing the samples to investigate the presence of the mutation. Eventually, genotypes associated with Cys87Tyr mutation were not observed in the studied population. Conclusion: In the present study, the G354A (Cys87Tyr) mutation associated with idiopathic hyperphosphatasia was not found in women with osteoporosis. Keywords: G354A mutation, OPG gene, Osteoporosi

The relationship between spiritual wellbeing and depression, stress, anxiety with cortisol level among nursing students

Introduction: Stress is a public health problem in today’s world. Spiritual health is one of the health dimensions that can affect the other ones. This study is about the connection between spiritual health and stress and cortisol level among nursing students.Materials and Methods: This study was a descriptive analytic search that was done in Azad University, Rasht on 2013. Total of 100 students were participated in this study. Our tools for collecting data were included: demographic information such as, age, sex, occupation and marital status situation. Also, questionnaire about depression, anxiety and stress measurement (Dass_21) were utilized. Additionally, standard questionnaire about spiritual health (SWB) were used. The cortisol plasma was measured with Eliza method.Results: According to this study, increasing the spiritual health will decrease depression, anxiety and stress among students. We also can conclude that by increasing the depression and anxiety, the cortisol level will increase. There is no connection between cortisol level and stress and spiritual health among these students, but there is a connection between believing in God (as a solution of problems and enjoying the life) and cortisol level