Can We Measure Individual Risk Attitudes in a Survey?

We combine a survey and an experiment with real pay-out among Peking University students to measure and validate individual risk attitudes. The experiment involves choosing between a cash payment and playing a lottery. The survey questions ask for the reservation price of a hypothetical lottery and self-assessment of risk attitude on a 0-10 scale. We confirm familiar findings: risk aversion dominates, women are more risk averse than men, risk aversion decreases with increasing parental income, risk attitudes are domain-specific. Correlations between survey measures and experimental measures, are in the right direction, but not very high. The survey measures are valid indicators of experimentally measured risk attitude, but with substantial noise remaining. Heterogeneity in levels and structures of risk attitude is large.risk attitude, survey question, experimental validation

Optofluidic Ring Resonator: A Versatile Microfluidic Platform for Chemical Vapor Detection and Intra-Cavity Biomolecular Analysis.

In the past few years, the optical ring resonator has emerged as a new sensing technology capable of detecting bio/chemical molecules in both liquid and vapor phase rapidly and sensitively. The ring resonator sensing relies on the whispering gallery mode (WGM) that forms due to total internal reflection of light at the curved resonator surface. The WGM has an extremely high Q-factor (>106). It circulates along the resonator circumference and repetitively interacts with the analyte near the resonator surface, thus resulting in an effective WGM-analyte interaction length of tens of centimeters. The optofluidic ring resonator (OFRR) is based on a thin-walled glass capillary whose circular cross section forms the ring resonator. The OFRR uniquely integrates the highly sensitive ring resonator technology and the superior fluidic handling capability of the capillary, and provides a very versatile technology platform for bio/chemical analysis. This thesis investigates two major OFRR sensing areas: chemical vapor detection and microfluidic laser intra-cavity biodetection. In the first area, the OFRR vapor sensing feasibility is first demonstrated with detection of representative gas analytes, followed by the theoretical analysis using a four-layer Mie model. Then the OFRR technology is integrated with micro-gas chromatography (mGC) to develop a highly sensitive and selective OFRR-mGC system. The dual use of the OFRR capillary as a separation column and an optical detector renders the OFRR-mGC system unique multi-point on-column detection capability. Using the OFRR-mGC system, rapid and sensitive detection of dinitrotoluene vapor out of interfering background is demonstrated. A tandem-column setting of the OFRR-mGC system is also explored to enhance the chromatographic resolution. A vapor mixture of twelve analytes of different volatilities and polarities are separated and detected within four minutes. In the second area, a bio-compatible optofluidic laser is developed based on the OFRR. A DNA scaffold is incorporated into the laser gain medium and controls the lasing emission properties through efficient fluorescence resonant energy transfer. This platform is further employed for highly-selective intra-cavity DNA detection. Two orders of magnitude improvement in detection selectivity is achieved over the conventional fluorescence detection method in differentiating the target and the single-base mismatched DNA sequences.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/89639/1/yuze_1.pd

A quasi-droplet optofluidic ring resonator laser using a micro-bubble

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98697/1/ApplPhysLett_99_091102.pd

Tunable single mode lasing from an on-chip optofluidic ring resonator laser

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98677/1/ApplPhysLett_98_061103.pd

Diffraction characteristics of radiated tilted fiber grating and its spectrometer application

We have numerically and experimentally presented the diffraction characteristics of radiated tilted fiber grating (RTFG) in terms of the spectrum, bandwidth, degree of polarization, angular dispersion, and temperature crosstalk. The theoretical and experimental results have shown that the polarization property, bandwidth, and dispersion of RTFG highly depended on the tilt angle of RTFG, and the RTFG has ultra-low temperature crosstalk. We have simulated the transmission spectrum of the RTFG with different tilt angles (25°, 31°, 38°, 45°, and 54°), in which the results show that the larger tilt angle has the wider bandwidth. The RTFGs with the tilt angle of 25°, 31°, 38°, 45°, and 54° have the 3dB bandwidth of 110 nm, 144 nm, 182 nm, 242 nm, and 301 nm, respectively. Besides, the degree of polarization (DOP) of the radiated light from RTFG with the different tilt angles are 0.876, 0.944, 0.967, 0.998, and 0.970, respectively, and the RTFG has the maximum DOP at the tilt angle of 45°, which could be used as single-polarization diffraction device. The experimental results show that with further increase or decrease of the tilt angle, the DOP of radiated light of RTFG would decrease. Both the theoretical and experimental results show that the smaller tilt angle could greatly improve the diffraction angular dispersion of RTFG, in which the 25°, 31°, 38°, and 45° RTFG have the angular dispersion of 0.2288 °/nm, 0.1026 °/nm, 0.0714 °/nm, and 0.0528 °/nm, respectively. Due to the broad working bandwidth, the diffraction angles of RTFG have ultra-low temperature crosstalk, where -0.00042, -0.00054, -0.00064, and -0.00099 degree / °C at the tilt angle of 25°, 31°, 38°, and 45°. Finally, we have demonstrated a miniaturized spectrometer integrated by a 25° RTFG, which has a high spectral resolution of 0.08 nm. The proposed RTFG would be an ideal in-fiber diffraction device and widely applied in spectral analysis, space optical communication, and Lidar areas

Classification of subtypes and identification of dysregulated genes in sepsis

BackgroundSepsis is a clinical syndrome with high mortality. Subtype identification in sepsis is meaningful for improving the diagnosis and treatment of patients. The purpose of this research was to identify subtypes of sepsis using RNA-seq datasets and further explore key genes that were deregulated during the development of sepsis.MethodsThe datasets GSE95233 and GSE13904 were obtained from the Gene Expression Omnibus database. Differential analysis of the gene expression matrix was performed between sepsis patients and healthy controls. Intersection analysis of differentially expressed genes was applied to identify common differentially expressed genes for enrichment analysis and gene set variation analysis. Obvious differential pathways between sepsis patients and healthy controls were identified, as were developmental stages during sepsis. Then, key dysregulated genes were revealed by short time-series analysis and the least absolute shrinkage and selection operator model. In addition, the MCPcounter package was used to assess infiltrating immunocytes. Finally, the dysregulated genes identified were verified using 69 clinical samples.ResultsA total of 898 common differentially expressed genes were obtained, which were chiefly related to increased metabolic responses and decreased immune responses. The two differential pathways (angiogenesis and myc targets v2) were screened on the basis of gene set variation analysis scores. Four subgroups were identified according to median expression of angiogenesis and myc target v2 genes: normal, myc target v2, mixed-quiescent, and angiogenesis. The genes CHPT1, CPEB4, DNAJC3, MAFG, NARF, SNX3, S100A9, S100A12, and METTL9 were recognized as being progressively dysregulated in sepsis. Furthermore, most types of immune cells showed low infiltration in sepsis patients and had a significant correlation with the key genes. Importantly, all nine key genes were highly expressed in sepsis patients.ConclusionThis study revealed novel insight into sepsis subtypes and identified nine dysregulated genes associated with immune status in the development of sepsis. This study provides potential molecular targets for the diagnosis and treatment of sepsis

Impact of charged ionic species (NaCl and KCl) on the generation of color and volatile aroma compounds during caramelization

During the process of caramelization, volatile and non-volatile flavor and color are generated via the degradation of carbohydrates. This research investigated the effect of the types and concentrations of salts including NaCl and KCl on the generation of volatile aromas and color during caramelization. The solid phase microextraction-gas chromatograph-mass spectrometry (SPME-GC-MS) was used to measure the volatile compounds generated in caramelization. The results demonstrated that increasing content of salt (NaCl or KCl) could significantly improve (P<0.05) the generation of some essential volatile compounds during caramelization such as furfural, 5-methylfurfural, 5-hydroxymethyl-furfural (HMF), propionic acid and butyric acid. However, the ascending amount of salt (NaCl or KCl) had no significant impact (P<0.05) on the color generation of caramel. In conclusion, the usage of salt was beneficial to the generation of more aromatic compounds during caramelization

Effects of agro-forestry systems on the physical and chemical characteristics of green coffee beans

Twenty agroforestry systems consisting of different management practices (conventional and organic) and shade types were set up for coffee plantations in 2,000 at the Tropical Agricultural Research and Higher Education Center (CATIE), Turrialba, Costa Rica. The physical (density, bulk density, moisture content, and roasting loss) and chemical attributes (mineral, total lipid, fatty acids, caffeine, and carbohydrate contents) of harvested green coffee beans were investigated. The full sun and Erythrina shade tree systems significantly improved (p < 0.05) the density of the green coffee beans and decreased (p < 0.05) the moisture content and roasting loss of the green coffee beans. The intensive organic (IO) management practice significantly increased some mineral contents, such as K, P, and Ca, in green coffee beans. The full sun system also significantly promoted (p < 0.05) some mineral contents, such as Ca and Mn, in green coffee beans. In terms of total lipid and fatty acids (FAs), compared with the moderate conventional (MC) management practice, the IO management practice was beneficial as it significantly increased (p < 0.05) the total lipid and FAs contents in the green coffee beans, while the Erythrina shade tree system significantly increased (p < 0.05) the total lipid and FAs contents of green coffee beans more efficiently than the other shade types. The caffeine content of green coffee beans was significantly higher (p < 0.05) under the intensive conventional (IC) and IO management practices than under the MC management practice and higher under the full sun system than under the shaded system. The Erythrina shade tree system significantly improved (p < 0.05) the carbohydrate content of green coffee beans. Overall, in consideration of sustainability, the IO management practice associated with the Erythrina shade tree system would be a useful combination for the local farmers to grow coffee trees

Revealing the crystalline packing structure of Y6 in the active layer of organic solar cells: the critical role of solvent additives

The bulk heterojunction (BHJ) morphology of photovoltaic materials is crucial to the fundamental optoelectronic properties of organic solar cells (OSCs). However, in the photoactive layer, the intrinsic crystalline packing structure of Y6, currently the hallmark molecule among Y-series non-fullerene acceptors (NFAs), has not been unambiguously determined. Here, employing grazing-incidence wide-angle X-ray scattering (GIWAXS), we managed to uncover the intrinsic crystalline packing structure of Y6 in the BHJ active layer of OSCs, which is found to be different from its single-crystal structure reported previously. Moreover, we find that solvent additive 1-chloronaphthalene (CN) can induce highly ordered packing of Y6 in BHJ thin films. With the help of atomistic molecular dynamics simulations, it is revealed that π-π interactions generally exist between naphthalene derivatives and IC terminals of Y6 analogues, which would essentially improve their long-range ordering. Our work reveals the intrinsic crystalline packing structure of Y6 in the BHJ active layer as well as its crystallization mechanism in thin films, thus providing direct correlations between this crystalline packing and the device characteristics and photophysical properties.Knut och Alice Wallenbergs StiftelseImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]