Study on shock wave and turbulent boundary layer interactions in a square duct at Mach 2 and 4

In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.     

Transient global amnesia after general anesthesia

OBJECTIVE: To investigate the prevalence of coronary artery disease (CAD), atherothrombotic brain infarction (ABI), and peripheral arterial disease (PAD) in older Hispanics and the association with risk factors in this population. DESIGN: A retrospective analysis of charts from all Hispanics seen during January 1996 through July 1997 at an academic hospital-based geriatrics practice. SETTING: An academic, hospital-based, primary care geriatrics practice staffed by fellows in a geriatrics training program and by full-time faculty geriatricians. PATIENTS: One hundred sixty women and 53 men, mean age 80 +/- 8 years (range 64 to 100), were included in the study. MEASUREMENTS AND MAIN RESULTS: Of 213 Hispanics in the study, 59 (28%) had documented CAD, 43 (20%) had ABI, 34 (16%) had PAD, and 90 (42%) had either CAD, ABI, or PAD. Serum total cholesterol and triglycerides were measured in 202 of 213 subjects (95%). Serum high-density lipoprotein cholesterol was measured in 137 of 213 patients (64%). Other risk factor data were documented in all patients. Multiple logistic regression analysis performed in 202 patients using the variables age, gender, cigarette smoking, hypertension, diabetes mellitus, obesity, serum total cholesterol, and serum triglycerides showed statistically significant associations between prevalent CAD, ABI, or PAD and age (P = .002, odds ratio (OR) = 1.083), cigarette smoking (P = .002, (OR) = 3.865), hypertension (P = .007, (OR) = 2.749), diabetes mellitus (P = .028, (OR) = 2.386), obesity (P = .014, (OR) = 2.608), serum total cholesterol (P < 0.001, (OR) = 1.025), and serum triglycerides (P = .017, (OR) = .993). CONCLUSIONS: Either CAD, ABI, or PAD was present in 42% of 213 older Hispanics. There were statistically significant associations between prevalent CAD, ABI, or PAD in older Hispanics and risk factors, including age, cigarette smoking, hypertension, diabetes mellitus, obesity, and serum total cholesterol.     

The network properties of bipolar-bipolar cell coupling in the retina of teleost fishes

Retinal bipolar cells exhibit a center-surround antagonistic receptive field to a light stimulus (Werblin & Dowling, 1969; Kaneko, 1970), and thus constitute an early stage of spatial information processing. We injected Lucifer Yellow and a small biotinylated tracer, biocytin, into bipolar cells of the teleost retina to examine electrical coupling in these cells. Lucifer-Yellow coupling was observed in one of 55 stained bipolar cells; the coupling pattern was one injected bipolar cell and three surrounding cells. Biocytin coupling was observed in 16 of 55 stained bipolar cells, six of which were ON center and ten OFF center. Although biocytin usually coupled to three to six bipolar cells, some OFF-center bipolar cells showed strong coupling to more than 20 cells. The biocytin-coupled bipolar cells were morphologically homologous. Membrane appositions resembling gap junctions were found between dendrites and between axon terminals of neighboring bipolar cells. In the strongest biocytin-coupled bipolar cells, the contacts between bipolar cells and cone photoreceptor cells were examined after reconstruction of the dendritic trees of five well-stained, serially sectioned OFF-center bipolar cells. Each of these bipolar cells was in contact with different numbers of cones: 11 to 20 for twin cones and two to four for single cones. This implies that, although these bipolar cells belong to the same category, the signal inputs differ among bipolar cells. Numerical simulation conducted on a hexagonal array network model demonstrated that the electrical coupling of bipolar cells can decrease the difference in input (approximately 80%) without causing significant loss of spatial resolution. Our results suggest that electrical coupling of bipolar cells has the advantage of decreasing the dispersion of input signals from cones, and permits bipolar cells of the same class to respond to light with similar properties.     

A Dual Selection Module for Directed Evolution of Genetic Circuits

We have developed a genetic selection module which enables us to select for positive and negative expression of a gene by controlling the expression of two antibiotic resistance genes. This module can be used to tune the performance of genetic circuits that yield simple ON/OFF gene expression outputs depending on the environment (input). We have demonstrated the utility of the module by selecting a genetic inverter from a 200 fold excess of nonfunctional inverters in two rounds.     

High Mobility and Luminescent Efficiency in Organic Single‐Crystal Light‐Emitting Transistors

A high‐performance ambipolar light‐emitting transistor (LET) that has high hole and electron mobilities and excellent luminescence characteristics is described. By using this device, a conspicuous light‐confined edge emission and current‐density‐dependent spectral evolution are observed. These findings will result in broader utilization of device potential and they provide a promising route for realizing electrically driven organic lasers.     

Mechanism‐Guided Library Design and Dual Genetic Selection of Synthetic OFF Riboswitches

After the recent discovery of bacterial riboswitches, synthetic riboswitches have been engineered by using natural and artificial RNA aptamers. In contrast to natural riboswitches, the majority of synthetic riboswitches in bacteria reported to date are ON switches that activate gene expression in response to the aptamer ligand. In this study, we adopted a mechanism‐guided approach to design libraries predisposed to contain OFF riboswitches that respond to thiamine pyrophosphate (TPP). The first library design exploited a pseudo‐Shine‐Dalgarno (SD) sequence located near the 3′‐end of the TPP aptamer, which would be less accessible to the ribosome when the aptamer is bound to TPP. In the second library, an SD sequence was strategically placed in the aptamer's P1 stem, which is stabilized upon ligand binding. OFF riboswitches were obtained by dual genetic selection of these libraries. The results underscore the importance of effective library design to achieve desired riboswitch functions.     

Incorporation of benzothiadiazole moiety at junction of polyfluorene–polytriarylamime block copolymer for effective color tuning in organic light emitting diode

Block copolymer consisting of polyfluorene and polytriarylamine with benzothiadiazole moiety at the junction is prepared in order to obtain an orange emitting polymer via Suzuki‐Miyaura followed by Buchwald‐Hartwig coupling reactions. Electroluminescent device fabricated with resulting block copolymer exhibit only orange emission, although slight blue emission is observed in the fluorescent spectrum for the thin film, indicating that benzothiadiazole part plays a role of an effective trap site. Devices based on polyfluorene homopolymer doped with block copolymer (10 wt %) or an orange emitting model compound at the corresponding content of benzotiadiazole unit are also fabricated. The device with the model compound exhibits orange emission with Commission Internationale de l'Éclairage (CIE) coordinate of (0.58, 0.42), whereas that with block copolymer pale orange with the coordinate of (0.44, 0.38). This fact is probably due to the preferential distribution of block copolymer at the vicinity of anode via hydrophilic interaction of trioxyethylene side chains with poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45393.     

The study on change of mechanical properties of NBR due to deterioration

Rubber is an important industrial material. However, mechanical properties and deformation of the high polymer including rubber are not clear. A method of estimating the mechanical properties which can be used for the deteriorated rubber is demanded to improve the reliability of it. Improved VBO (Viscoplasticity theory based on overstress) model is a constitutive equation. We applied it for the compression stress-strain behavior of deteriorated NBR (acryloNitrile-Butadiene rubber). Furthermore, we proposed a method of estimating the mechanical properties of deteriorated NBR. In this paper, deterioration tests in water and in air were conducted. To confirm the validity of the proposed improved VBO model and estimated mechanical properties, simulations of the stress-strain curves obtained in the tests were conducted.     

A Comprehensive Study of the Interaction between Peptidoglycan Fragments and the Extracellular Domain of Mycobacterium tuberculosis Ser/Thr Kinase PknB

The Mycobacterium tuberculosis Ser/Thr kinase PknB is implicated in the regulation of bacterial cell growth and cell division. The intracellular kinase function of PknB is thought to be triggered by peptidoglycan (PGN) fragments that are recognized by the extracytoplasmic domain of PknB. The PGN in the cell wall of M. tuberculosis has several unusual modifications, including the presence of N-glycolyl groups (in addition to N-acetyl groups) in the muramic acid residues and amidation of d -Glu in the peptide chains. Using synthetic PGN fragments incorporating these diverse PGN structures, we analyzed their binding characters through biolayer interferometry (BLI), NMR spectroscopy, and native mass spectrometry (nMS) techniques. The results of BLI showed that muropeptides containing 1,6-anhydro-MurNAc and longer glycan chains exhibited higher binding potency and that the fourth amino acid of the peptide stem, d -Ala, was crucial for protein recognition. Saturation transfer difference (STD) NMR spectroscopy indicated the major involvement of the stem peptide region in the PASTA-PGN fragment binding. nMS suggested that the binding stoichiometry was 1:1. The data provide the first molecular basis for the specific interaction of PGN with PknB and firmly establish PGNs as the effective ligands of PknB.     

东京奥运会前后有关公园绿地功能的讨论与收获

以“绿色奥运“为口号的北京市,正在着手2008年奥运会的各种建设。在这种大规模建设中,如何将“绿色”要素,贯穿于空间及设施中,这些设施建成后,将对北京市的公园绿地系统产生何种影响,是景观园林专家们所关注的焦点。通过东京奥运会前后日本国内对公园绿地功能的反复讨论及当时的资料介绍,阐述其对现阶段城市公园绿地形成的重要价值,以期为当前的绿地规划及各项决策提供参考。研究结果明确提出了“公园绿地功能”与“运动”相互关系的总体构架,并提出建造绿地空间时应注意的重点。