Glandular Trichome Extracts from Medicago sativa Deter Settling by the Potato Leafhopper Empoasca fabae

Extracts of glandular trichomes from Medicago sativa were tested for their ability to disrupt the settling behavior of the potato leafhopper, Empoasca fabae. Erect and procumbent glandular trichomes were mechanically isolated from stem sections of resistant genotype "G98A," and nonglandular trichomes were collected from susceptible cultivar "Ranger." Isolated trichomes were extracted with chloroform, acetone, and ethanol, and the resulting crude extracts were applied to the surface of a sachet containing an artificial diet. Leafhoppers were offered a two-way choice between crude trichome extracts from G98A and Ranger. All three of G98A solvent extracts caused various degrees of diet rejection, resulting in the crude Ranger trichome extracts being preferred over G98A extracts. Overall, the fewest leafhoppers settled on the ethanolic extracts. Additional bioassays documented a dose response associated with G98A ethanolic extracts when compared with Ranger trichome extracts and a solvent control. No difference in preference behavior was detected between Ranger trichome extracts and a solvent control. Gas chromatography-mass spectrometry analysis revealed a homologous series of nonvolatile fatty acid amides C(n)H(2n+1)NO (n = 19-23) unique to G98A glandular trichome extracts.     

DS3600系列在嵌入式安全系统中的应用

随着安全性需求不断渗透到电子系统设计制造的各个环节，电子设计人员面临着前所未有的挑战。本文介绍基于DS3600系列安全控制器进行的一些安全系统设计的优势所在。     

Calculation of reliability for time-varying loads and resistances

There are many elements of structural loads and resistances that vary with time. For bridges, the live loads generally increase; that is, the mean of the live load density function increases with time. The resistances may increase, as in the case of concrete curing or timber seasoning; they may also decrease, as in the case of prestressing losses, material deterioration, or timber moisture gain. In calculating reliabilities, the time-varying nature of the above-mentioned elements is often ignored or represented only by a single averaged coefficient.

A method is presented for including such important time-dependent elements in the reliability equation. The equation is derived and applied to the reliability analysis of a prestressed concrete bridge girder. The analysis considers the reliability against flexural cracking due to live loads over a 50-year life. Both the concrete compressive strength and the live loads are assumed to increase with time. For the assumed distributions and time relationships the time-reliability equation indicates higher reliabilities than those found by conventional level-III reliability analyses.     

Subcellular effects and localization of binding sites of phytohemagglutinin in the potato leafhopper, Empoasca fabae (Insecta: Homoptera: Cicadellidae)

To identify the means by which phytohemagglutinin (PHA) exerts its toxicity on the potato leafhopper, four different methods (thick and semi-thin sectioning combined with immunofluorescent staining, in vitro receptor autoradiography, and immunoelectron microscopy) were used to elucidate the PHA target tissue, binding site, and its effects on this tissue. Sixteen 1- or 2-day-old female potato leafhoppers were fed for 36 h on each of three treatments: a control, diet or a diet containing either the PHA-E subunit or the PHA-L subunit. The PHA-E subunit, but not PHA-L, had previously been shown to be lethal. The insects were then prepared for both light and confocal microscopy. Analysis of images showed that PHA bound only to the surface of midgut epithelial cells of the potato leafhopper. PHA-E caused severe disruption, disorganization, and elongation of the brush border microvilli, and swelling of the epithelial cells into the lumen of the gut, leading to complete closure of the lumen. Furthermore, PHA-E stimulated the division of midgut epithelial cell nuclei, leading to two nuclei in each cell. Nuclei later elongated and degraded. In contrast, PHA-L had little effect on the epithelial cells of the midgut. It did not strongly bind to the surface of epithelial cells and caused much less disruption of brush-border microvilli, less disorganization of the cells and less elongation of nuclei. Strong binding of PHA occurred solely on the cell membrane of the brush border microvilli of epithelial cells. In contrast, the controls (i.e., midgut tissue, blocking agent, PHA, and antibodies) showed that midgut tissue was not autofluorescent and showed no fluorescent binding signal. Analysis of both bright- and dark-field images obtained by autoradiography and immunoelectron microscopy confirmed these findings.     

Interrelationships of clinical outcome, length of resection, and energy cost of walking after prosthetic knee replacement following resection of a malignant tumor of the distal aspect of the femur

An automated method for analysis of in vivo proton magnetic resonance (MR) spectra and reconstruction of metabolite distributions from MR spectroscopic imaging (MRSI) data is described. A parametric spectral model using acquisition specific, a priori information is combined with a wavelet-based, nonparametric characterization of baseline signals. For image reconstruction, the initial fit estimates were additionally modified according to a priori spatial constraints. The automated fitting procedure was applied to four different examples of MRS data obtained at 1.5 T and 4.1 T. For analysis of major metabolites at medium TE values, the method was shown to perform reliably even in the presence of large baseline signals and relatively poor signal-to-noise ratios typical of in vivo proton MRSI. Identification of additional metabolites was also demonstrated for short TE data. Automated formation of metabolite images will greatly facilitate and expand the clinical applications of MR spectroscopic imaging.     

Human quality control in naval air training.

"In training programs, whether these be military… or civilian… quality control requirements exist… . This paper describes an important instance of the application of psychological research methods to human quality control over a total training program… . Human quality control… should start with identification of graduates who have been unsuccessful on the job and work backwards to the determination of those minimum standards which will prevent the selection and/or graduation of potential failures… . minimum standards already installed and under investigation should reduce the number of unsatisfactory men reaching the fleet by about 50%." The study of minimum training standards is a continuing one. The procedures for translating criterion data into an effective quality control program are summarized in 5 steps. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Atmospheric flows of semi-volatile organic pollutants to the Great Lakes estimated by the United States' Integrated Atmospheric Deposition and Canada's Great Lakes Basin Monitoring and Surveillance Networks

We calculated the wet and dry deposition, vapor absorption, and volatilization flows (in kg/yr) of seven polychlorinated biphenyls (PCBs), nine organochlorine pesticides, and two polycyclic aromatic hydrocarbons (PAHs) into and out of the Great Lakes during 2010–2015 (inclusive). Particle, vapor, and precipitation concentrations from five rural and remote stations (one site on each lake) and two urban sites, operated by the United States and Canada, were used for the flow calculations. Output from the water to the air was the most important process for PCBs, chlordanes, and p,p′-DDE. The flows of endosulfan, p,p′-DDT, and phenanthrene were dominated by vapor absorption from the air to the water. The flow of benzo[a]pyrene was controlled by wet and dry deposition to the water. The flows of the hexachlorocyclohexanes (HCHs) into and out of the lakes were about equal, indicating air-water equilibrium for these compounds. Among the lakes, Lakes Superior and Erie had the highest input and output flows. The input and output flows for the five lakes were decreasing with halving times of 1–10 years and 10–40 years, respectively. Most chemicals had seasonal variations in their flows, with maximum inputs in the summer and maximum outputs in the fall. The flows of PCBs and PAHs into Lakes Michigan and Erie were associated with Chicago and Cleveland, respectively. Combining our data with previous data over the period 1992–2015, we estimated that the input flows of most of these chemicals have significantly decreased, but the output flows do not show consistent trends.     

Design and testing of the JPL‐Nautilus Gripper for deep‐ocean geological sampling

We present the design and experimental results for the JPL‐Nautilus Gripper, a 16‐finger highly underactuated microspine gripper for use in the deep ocean. The gripper can grasp objects from 10 to 30 cm in size and anchor to flat and curved rocky surfaces (i.e., cliff faces and seamounts). Laboratory results demonstrated an anchoring capability of greater than 450 N on rough rocks in both shear and normal loading directions. Deployment on the Hercules ROV (remotely operated vehicle) aboard the E/V Nautilus on three deep‐ocean dives verified performance at depths up to to 2,100 m with approximately 100 N loads applied through the ROV's thrusters, including moment loads. The gripper also serves as a development unit for future robotic tools that will include a coring drill in the center of the gripper, as previously demonstrated in non‐ocean environments with microspine grippers. Such a tool will facilitate the collection of geologic samples from the deep ocean using more agile and cost‐effective systems.