synthesis and characterization of mononuclear and polynuclear metal-fullerene complexes

[[abstract]]The reaction of Ru\sb6C(CO)\sb17Ru\sb6C(CO)\sb17 with C\sb60\sb60 followed by carbonyl substitution with bis(diphenylphosphino)methane gave Ru\sb6C(CO)\sb12(dppm)(μ\sb3Ru\sb6C(CO)\sb12(dppm)(μ\sb3-η\sp2,η\sp2,η\sp2η\sp2,η\sp2,η\sp2-C\sb60).\sb60). A related arene-Ru\sb6\sb6C compound, Ru\sb6C(CO)\sb13{PPh\sb2(μRu\sb6C(CO)\sb13{PPh\sb2(μ-η\sp6η\sp6-C\sb6H\sb6)},C\sb6H\sb6)}, was obtained by thermolysis of Ru\sb6C(CO)\sb16PPh\sb3,Ru\sb6C(CO)\sb16PPh\sb3, in which the tendency of the Ru\sb6\sb6C framework to form arene complexes is extend to a coordinated triphenylphosphine moiety, leading to (reversible) coordination of a phenyl ring to an adjacent ruthenium center in the cluster unit

Enantiotropic nematics from cross-like 1,2,4,5-tetrakis(4'-alkyl-4-ethynylbiphenyl)benzenes and their biaxiality studies

[[abstract]]The theoretically predicted optimum length/breadth/width ratio for maximizing shape biaxiality was investigated experimentally by the facile and successful synthesis of cross-shaped compound 3, which showed enantiomeric nematic phase behavior. This cross-like core structure could alternatively be viewed as two fused V-shaped mesogens, which have recently immerged as a new direction in biaxial nematic research, at the bending tips that can act as a new structure for biaxial investigations. Whilst the thermal analysis data of compound 3 did not meet the expected theoretical values for biaxial nematics, surface-induced biaxiality was evidenced by optical studies. Cluster-size analysis within the nematic phase of compound 3 revealed the formation of meta-cybotactic nematics, which approached the cluster sizes of cybotactic nematics. The split small-angle 2D X-ray diffraction patterns of magnetic-field-aligned samples indicated that the nematic phase was composed of small smectic C-like clusters with the tilting of molecules within the clusters. The wide-temperature-range enantiomeric nematic phase of cross-like compound 3 enabled the molecular skeleton to serve as an alternative skeleton to bent-rod mesogens, which exhibited nematic phases with the potential competition of transitions to higher-order liquid-crystalline phases and crystallization, for future biaxial investigations.[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]紙本[[booktype]]電子版[[countrycodes]]DE

Single-component room-temperature discotic nematic liquid crystals formed by introducing an attraction-enhancing in-plane protrusion onto the hexa(phenylethynyl)benzene core

[[abstract]]Single-component room-temperature discotic nematics have been achieved within large temperature ranges by introducing an attraction-enhancing protrusion onto hexa(phenylethynyl)benzenes. X-ray diffraction investigations revealed the nematic phases of these new discotic nematic materials to be cybotactic.[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Electrical Pulse Triggered Reversible Assembly of Molecular Adlayers

[[abstract]]Reversible adlattice assembly for alkoxy-decorated aromatics is controllable by short electrical pulses.[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Influence of Mesogenic Properties of Cruciform-Shaped Liquid Crystals by Incorporating Side-Arms with a Laterally-Substituted-Fluorine

[[abstract]]Fluoro substitution in thermotropic liquid crystals provides a general way of modifying the properties of a parent system. Transition temperatures, mesophase types and other physical properties can be affected by fluoro substitution, so that frequently the behaviors of the parent compound can be manipulated and improved in a predictable manner. This paper discusses the effects of a fluoro substitution in each side-arm of 1,2,4,5-tetrakis((4-(alkoxy)phenyl)ethynyl)benzenes on the resulting mesomorphic properties characterized by optical polarizing microscopy and differential scanning calorimetry. Without any fluoro-substituted side-arms, longer chain-length leads to a wider nematic temperature range on cooling. Incorporation of a fluoro substitution in each side-arm induces the formation of a lamellar suprastructure, lowers transition temperatures and results in a wider mesophase temperature range on cooling.[[sponsorship]]國科會[[booktype]]電子

Design and investigation of calamitic liquid crystals with low aspect-ratios : Rigid y-shaped 1,2,4-tris(4-alkoxyphenylethynyl)benzenes

[[abstract]]The synthesis and characterization of triynylbenzenes, 1-iodo-2,4,5-tri(4-alkoxyphenylethynyl)benzenes (1), are reported, and their structure–mesomorphism relationship is investigated. These compounds possess a y-shaped geometry with rigid linear spacers and a stable nematic phase that was achieved by lengthening the alkoxy chains or replacing the iodo group with a smaller atom. The low aspect ratios and identified calamitic nature of these rigid y-shaped liquid crystals make them suitable as potential candidates to be used in the liquid crystal layer of liquid crystal display devices for improving viewing angles. In addition, the geometry of 1 was modified stepwise from a rigid y-geometry to a rigid rectangle for realization of the unstable nematic behaviors of the previously reported board-like 1,2,4,5-tetrakis(4-tridecyloxyphenylethynyl)benzene that was expected to potentially show biaxial nematic phases. The sizes of the fourth side-arm and hence the aspect ratios of these tetra-substituted benzenes are ascribed to the less liquid crystallinity.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Food Traceability Systems, Consumers’ Risk Perception, and Purchase Intention: Evidence from the “4-label-1-Q” Approach in Taiwan

Many food safety issues have arisen in Taiwan during the past decade. Therefore, in 2016, the Taiwan government proposed the "five rings of food safety" policy to comprehensively protect consumer food supply. Among these policies, the "4-labels-1-Q" approach was adopted to ensure the selection of foods with traceable labels for retrospective study. Hence, this study investigated the association between the degree of familiarity with the 4-labels-1-Q food traceability system and risk perceptions and also investigated whether a consumer's purchase intention toward fresh foods with food labels changed after viewing an educational film on food labels. This study defined subjects as the main food purchasers for their families; 290 valid questionnaire interviews were administered and educational films shown in Tainan markets and stores. Results showed that knowledge about labels significantly affected risk perception for labeling. Age, educational level, and degree of risk perception influenced purchase intention. Results also showed that after viewing the video, subjects' label knowledge and purchase intention increased significantly. However, after adjustment for age, educational level, income, and purchase places, the effect of film education on risk perception was insignificant, especially for those who had lower educational levels, including those older than 65 years. Public trust can be boosted through label education among age groups using different channels and methods, and encouraging the sale of labeled foods in traditional markets would be a useful strategy. Age, educational level, income, and risk perception of participants significantly affected purchase intention. This study can be a reference for designing risk communication strategies and promoting traceable agricultural products

Investigation of Novel Noncontacting Measurement Method by the Design of Loop-Type Probe and Reconstruction of Radiation Modeling

Because the ICs’ application frequency and speed become higher and trends of system packaging and device under test request higher reliability, a novel technology combining noncontacting measurement method and reconstructing radiation model was proposed to solve signal deliveries in system packages or PCBs. In this study, a novel noncontacting method for the ICs’ measurements was investigated by the design of loop-type near-field probe and reconstructed the radiation model to substitute the traditional measurement methods, such as using probes and SMA connectors. A near-field probe was used to receive the coupling signal. The assessing circuit modeling could be completed by some synthesized theorems. According to the study’s results, frequency responses of reconstruction model developed by theorems, radiation measurements, and simulated by EM methods were highly curve fitting

Plasma Low-Density Lipoprotein Cholesterol Correlates With Heart Function in Individuals With Type 2 Diabetes Mellitus: A Cross-Sectional Study

Background: Heart failure is a frequent complication of type 2 diabetes mellitus (T2DM). Plasma cholesterol, particularly the proatherogenic low-density lipoprotein (LDL) cholesterol, impairs heart function by promoting atheroma formation and ventricular dysfunction. Considering the established effect of cholesterol on the cardiovascular system, we hypothesized that plasma LDL cholesterol may influence left ventricular function in individuals with T2DM.Methods: This cross-sectional study was conducted at a tertiary care hospital in Taiwan. Enrollment criteria were patients exceeding 21 years of age with T2DM who received antidiabetic and cholesterol-lowering medications. Candidates were excluded if they had heart failure, acute cardiovascular events, or familial hypercholesterolemia. Participants received blood sampling for plasma lipids after a 12-h fast, followed by transthoracic echocardiography in the cardiology clinic.Results: The study enrolled 118 participants who were divided into two groups according to their plasma LDL cholesterol levels. Demographic characteristics including age (69.7 vs. 66.9 years, P = 0.159), body mass index (26.2 vs. 25.9 kg/m2, P = 0.66), diabetes duration (5.4 vs. 5.1 years, P = 0.48), hemoglobin A1c (7.2 vs. 7.5%, P = 0.225), and systolic blood pressure (129 vs. 130 mm Hg, P = 0.735) were similar between these groups. Moreover, all participants received similar antihypertensive medications. Participants with lower plasma LDL cholesterol levels had better heart function, as measured by the left ventricular ejection fraction (LVEF), than patients with higher LDL cholesterol levels (58.0 vs. 50.5%, P = 0.022). Multivariate regression analysis also showed an inverse correlation between plasma LDL cholesterol and left ventricular function (β coefficient: −0.110, P = 0.024).Conclusion: This study observed an inverse correlation between plasma LDL cholesterol and heart function in individuals with T2DM. Patients with higher levels of plasma LDL cholesterol had worse left ventricular function. Therefore, plasma LDL cholesterol may be a modifiable risk factor of heart failure in diabetes, but prospective studies are necessary to confirm this finding

Electromagnetic Wave Theory and Applications

Contains table of contents for Section 3, reports on six research projects and a list of publications and conference papers.Joint Services Electronics Program Contract DAAL03-89-C-0001National Science Foundation Grant ECS 86-20029Schlumberger- Doll ResearchU.S. Army Research Office Contract DAAL03 88-K-0057U.S. Navy - Office of Naval Research Contract N00014-90-J-1002National Aeronautics and Space Administration Grant NAGW-1617U.S. Navy - Office of Naval Research Grant N00014-89-J-1107National Aeronautics and Space Administration Grant NAGW-1272National Aeronautics and Space Administration Agreement 958461U.S. Army - Corps of Engineers Contract DACA39-87-K-0022U.S. Air Force - Electronic Systems Division Contract F19628-88-K-0013U.S. Navy - Office of Naval Research Grant N00014-89-J-1019Digital Equipment CorporationIBM CorporationU.S. Department of Transportation Contract DTRS-57-88-C-00078Defence Advanced Research Projects Agency Contract MDA972-90-C-002