Vision-based flight control in the hawkmoth Hyles lineata

Vision is a key sensory modality for flying insects, playing an important role in guidance, navigation and control. Here, we use a virtual-reality flight simulator to measure the optomotor responses of the hawkmoth Hyles lineata, and use a published linear-time invariant model of the flight dynamics to interpret the function of the measured responses in flight stabilization and control. We recorded the forces and moments produced during oscillation of the visual field in roll, pitch and yaw, varying the temporal frequency, amplitude or spatial frequency of the stimulus. The moths’ responses were strongly dependent upon contrast frequency, as expected if the optomotor system uses correlation-type motion detectors to sense self-motion. The flight dynamics model predicts that roll angle feedback is needed to stabilize the lateral dynamics, and that a combination of pitch angle and pitch rate feedback is most effective in stabilizing the longitudinal dynamics. The moths’ responses to roll and pitch stimuli coincided qualitatively with these functional predictions. The moths produced coupled roll and yaw moments in response to yaw stimuli, which could help to reduce the energetic cost of correcting heading. Our results emphasize the close relationship between physics and physiology in the stabilization of insect flight.     

Sensitive and reproducible intact mass analysis of complex protein mixtures with superficially porous capillary reversed-phase liquid chromatography mass spectrometry

The compatibility of superficially porous (SP) resin for label-free intact protein analysis with online capillary LC/MS is demonstrated to give improved chromatographic resolution, sensitivity, and reproducibility. The robustness of the platform was measured against several samples of varying complexity and sample loading amount. The results indicate that capillary SP columns provide high loading capacities and that ～6 s chromatographic peak widths are typical for standard proteins in simple mixtures and proteins isolated from cell and tissue lysates. Subfemtomole detection limits for standard proteins were consistently observed, with the lowest levels at 12 amol for ubiquitin. The analysis of total heart homogenates shows that capillary SP columns provide theoretical peak capacity of 106 protein forms with 30 min total analysis time and enabled detection of proteins from complex mixtures with a single high-resolution scan. The SPLC/MS platform also detected 343 protein forms from two HeLa acid extract replicate analyses that consumed 5 × 10(4) cells and 30 min analysis time, each. Comparison of all the species observed in each HeLa replicate showed 90% overlap (309 forms) with a Pearson correlation coefficient of 89.9% for the common forms observed in the replicates. Efficient acid extract of 1 × 10(4) HeLa cells allowed reproducible detection of common modification states and members from all five of the histone families and demonstrated that capillary SPLC/MS supports reproducible label-free profiling of histones in <15 min total analysis time. The data presented demonstrate that a capillary LC/MS platform utilizing superficially porous stationary phase and a LTQ-Orbitrap FT-MS is fast, sensitive, and reproducible for intact protein profiling from small tissue and cell amounts.     

Pilot-scale evaluation of ozone and biological activated carbon for trace organic contaminant mitigation and disinfection

In an effort to validate the use of ozone for contaminant oxidation and disinfection in water reclamation, extensive pilot testing was performed with ozone/H₂O₂ and biological activated carbon (BAC) at the Reno-Stead Water Reclamation Facility in Reno, Nevada. Three sets of samples were collected over a five-month period of continuous operation, and these samples were analyzed for a suite of trace organic contaminants (TOrCs), total estrogenicity, and several microbial surrogates, including the bacteriophage MS2, total and fecal coliforms, and Bacillus spores. Based on the high degree of microbial inactivation and contaminant destruction, this treatment train appears to be a viable alternative to the standard indirect potable reuse (IPR) configuration (i.e., membrane filtration, reverse osmosis, UV/H₂O₂, and aquifer injection), particularly for inland applications where brine disposal is an issue. Several issues, including regrowth of coliform bacteria in the BAC process, must be addressed prior to full-scale implementation.     

Removal of heavy metals from aqueous systems with thiol functionalized superparamagnetic nanoparticles

We have shown that superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) are an effective sorbent material for toxic soft metals such as Hg, Ag, Pb, Cd, and Tl, which effectively bind to the DMSA ligands and for As, which binds to the iron oxide lattices. The nanoparticles are highly dispersible and stable in solutions, have a large surface area (114 m2/g), and have a high functional group content (1.8 mmol thiols/g). They are attracted to a magnetic field and can be separated from solution within a minute with a 1.2 T magnet. The chemical affinity, capacity, kinetics, and stability of the magnetic nanoparticles were compared to those of conventional resin based sorbents (GT-73), activated carbon, and nanoporous silica (SAMMS) of similar surface chemistries in river water, groundwater, seawater, and human blood and plasma. DMSA-Fe3O4 had a capacity of 227 mg of Hg/g, a 30-fold larger value than GT-73. The nanoparticles removed 99 wt% of 1 mg/L Pb within a minute, while it took over 10 and 120 min for Chelex-100 and GT-73 to remove 96% of Pb.     

Process Limits of Municipal Wastewater Treatment with the Submerged Membrane Bioreactor

The submerged membrane bioreactor (SMBR) is a promising technology for wastewater treatment and water reclamation. This paper presents results from two pilot scale SMBR systems operating in parallel on municipal wastewater in San Diego, Calif. The SMBRs were operated to address the limitations and advantages of the SMBR process compared to conventional activated sludge processes. Minimal membrane fouling was observed throughout the year of testing with the exception of the process limitations. Both pilot units provided consistently high quality effluents throughout the study, even when operating at hydraulic retention times as low as 1.5 h. Two sets of experiments were conducted to identify different fouling conditions. The first experiments were conducted to explore operation at high suspended solids concentrations. The SMBR process experienced adverse performance at mixed liquor suspended solids concentrations greater than approximately 20?g/L. The second experiments explored operation at low mean cell residence time (MCRT). At an MCRT of <2 days, membrane fouling was rapid. Chemical cleaning with sodium hypochlorite solution provided full recovery of the membrane permeability.     

The indications for the appropriate use of magnetic resonance. The Health Technologies Evaluation Service of the Department of Health of the Basque Government, Osteba

Magnetic resonance imaging (MRI) allows the non-invasive obtention of diagnostic images, with no ionizing radiation emission and in any space plane. It has a great capacity to differentiate anatomic structures, and it is very useful for planning surgery or radiotherapy. It is the first choice diagnostic technique in conditions involving the central nervous system, useful for establishing diagnosis, surgery planning, and following lesions involving the spinal cord and spine. In the musculoskeletal system it may become and appropriate alternative to arthroscopy. Nevertheless, it is of limited use for the diagnosis of chest, abdominal and pelvic pathology.     

High TC superconductor polymer composite based on YBa2Cu3O7−x. II. Conduction mechanisms and temperature effect on conductive and dielectric properties of polypropylene composites

To improve the connectivity of YBaCuO particles in a polypropylene matrix, different amounts of carbon black (N) or copper (C) were incorporated into the binary base system. In this research the effects of these conductor fillers on the conduction mechanism of the experimental composites were studied using complex impedance spectroscopy as the analytical technique. In addition the effects of temperature on certain electrical properties were examined in the synthesized materials. © 1995 John Wiley & Sons, Inc.     

Modified sperm stress test: a simple assay that predicts sperm-related abnormal in-vitro fertilization

Loss of sperm motility is associated with the process of sperm senescence and occurs at different rates within a given normal or abnormal sperm population. Reactive oxygen species attack cell membrane phospholipids, generating fatty acid peroxides and other degradation products, that also have deleterious effects on sperm motility and fertilizing ability. The objective of this investigation was to study a modification of the original sperm stress test (MOST), changing the culture medium to one offering transitional metals and shortening the total test time, to ascertain whether it can predict fertilization under these laboratory conditions. A total of 41 semen samples was obtained from patients undergoing in-vitro fertilization (IVF) at our institution. Semen samples were grouped into those producing total fertilization rates (FR) within normal limits (>50%) and those showing low total FR (<50%). The normal FR group had a significantly greater MOST mean value than the low FR group (0.71 versus 0.44). Furthermore, there was a statistically significant correlation between the MOST score and ungrouped fertilization rates (r = 0.53, P = 0.0004). Diagnostic statistics for MOST ratio values predicting <50% FR showed an optimal threshold of 0.39. Collectively, sensitivity, specificity, positive predictive value and negative predictive value have their largest values at this threshold. Taking into account the above mentioned threshold figures, there is a significant association between MOST and FR categories (P = 0.0009). In conclusion, MOST is a simple assay that has significant predictive value for sperm related IVF abnormalities.