An adeno-associated viral vector transduces the rat hypothalamus and amygdala more efficient than a lentiviral vector

Background  

This study compared the transduction efficiencies of an adeno-associated viral (AAV) vector, which was pseudotyped with an AAV1 capsid and encoded the green fluorescent protein (GFP), with a lentiviral (LV) vector, which was pseudotyped with a VSV-G envelop and encoded the discosoma red fluorescent protein (dsRed), to investigate which viral vector transduced the lateral hypothalamus or the amygdala more efficiently. The LV-dsRed and AAV1-GFP vector were mixed and injected into the lateral hypothalamus or into the amygdala of adult rats. The titers that were injected were 1 × 10⁸ or 1 × 10⁹ genomic copies of AAV1-GFP and 1 × 10⁵ transducing units of LV-dsRed.     

Multiple localized exciton species in sulfied-doped AgBr detected by luminescence and ODMR

Abstract

The low temperature photoluminescence of sulfide-doped AgBr has been examined with both steady state and pulsed excitation. Emission bands peaking at about 495, 566, 596, and 725 nm are observed, depending upon excitation conditions. Subband-gap excitation resonances at 464, 496, 530, and 558 nm are observed, depending upon monitoring wavelength. Excitation at 496 nm preferentially enhances 596 nm emission, which gives rise to an ODMR spectrum. ODMR data indicate that at least three species are contributing to the 596 nm emission. These species are interpreted as triplet excitons. A highly antisotropic species observed in the ODMR spectra is interpreted as a triplet exciton bound to a substitutional divalent sulfur ion/interstitial silver ion complex with approximate [111] symmetry.     

Inner hair cell responses to the 2f1-f2 intermodulation distortion product

Recordings of dc and ac receptor potentials from pigmented guinea pig inner hair cells indicate strong responses to the 2f1-f2 intermodulation tone when f1 and f2 are greater than the hair cell characteristic frequency and do not cause a response when given individually. The effective magnitude of this cubic distortion product (CDP) was about 25-30 dB below equal sound level primaries over a 20-30-dB range of their sound levels. The relative strength of the CDP declined at a rate greater than 180-dB/oct separation of the primaries. When magnitude of f1 or f2 was held constant, the growth of CDP was nonmonotonic, exhibiting a distinct maximum. With a constant level of f1 or f2, optimal CDP was produced when the level of f2 was 10-15 dB greater than f1. Strong two-tone suppression from the primaries has a role in shaping the CDP growth. The ac receptor potentials of the CDP show a 150 degrees-200 degrees phase shift when the primaries are increased over a 50-dB range. These results support the hypothesis of a propagated CDP in the cochlea and are consistent with the major features of related studies of human psychoacoustic experiments, afferent nerve neural rate functions, and ear canal distortion products.     

Backlund transformations and exact solutions for a nonlinear elliptic equation modelling isothermal magnetostatic atmosphere

The equations of magnetostatic equilibria for a plasma in agravitational field are investigated analytically. For equilibriawith an ignorable spatial coordinate, the equations reduce toa single nonlinear elliptic equation for the magnetic potentialu known as the Grad-Shafranov equation. By specifying the arbitraryfunctions in this equation, a Liouville equation is obtained.Bäcklund transformations are described and applied to obtainexact solutions for the Liouville equation modelling an isothermalmagnetostatic atmosphere, in which the current density J isproportional to the exponential of the magnetic potential andmoveover falls off exponentially with distance vertical to thebase with an e-folding distance equal to the gravitational scaleheight.     

Structure and bonding in the metal complexes of ethylenediaminetetra-acetic acid

The metal-ion complexes of ethylenediaminetetra-acetic acid (EDTA) find widespread use not only in analysis, but also in foodstuffs, pharmacy, and medicine. A review of the structures of the solid complexes illustrates the considerable variation in co-ordination number of the metal-ion, and the possible denticities of EDTA. These data are relevant to the solid-state properties and also to the structures of the complexes in solution, which cannot be directly determined.     

Basilar-membrane responses to multicomponent (Schroeder-phase) signals: understanding intensity effects

Harmonic complexes comprised of the same spectral components in either positive-Schroeder (+Schr) or negative-Schroeder (-Schr) phase [see Schroeder, IEEE Trans. Inf. Theory 16, 85-89 (1970)] have identical long-term spectra and similar waveform envelopes. However, localized patterns of basilar-membrane (BM) excitation can be quite different in response to these two stimuli. Measurements in chinchillas showed more modulated (peakier) BM excitation for +Schr than -Schr complexes [Recio and Rhode, J. Acoust. Soc. Am. 108, 2281-2298 (2000)]. In the current study, laser velocimetry was used to examine BM responses at a location tuned to approximately 17 kHz in the basal turn of the guinea-pig cochlea, for +Schr and -Schr complexes with a 203-Hz fundamental frequency and including 101 equal-amplitude components from 2031 to 22,344 Hz. At 35-dB SPL, +Schr response waveforms showed greater amplitude modulation than -Schr responses. With increasing stimulation level, internal modulation decreased for both complexes. To understand the observed phenomena quantitatively, responses were predicted on the basis of a linearized model of the cochlea. Prediction was based on an "indirect impulse response" measured in the same animal. Response waveforms for Schroeder-phase signals were accurately predicted, provided that the level of the indirect impulse used in prediction closely matched the level of the Schroeder-phase stimulus. This result confirms that the underlying model, which originally was developed for noise stimuli, is valid for stimuli that produce completely different response waveforms. Moreover, it justifies explanation of cochlear filtering (i.e., differential treatment of different frequencies) in terms of a linear system.     

The user and terrain-machine system research

Designing off-road equipment to meet user requirements assumes that research results are brought to bear on real design problems, that the user has been identified, and that the user's needs are communicated to the designer. In the area of military vehicles, these conditions are met. The U.S. Army Mobility Model is an example of how this is done.The Army Mobility Model, a computer simulation technique, allows terrain, vehicle, and driver characteristics to be combined to predict the performance of vehicles according to various criteria such as speed, fuel consumption, etc. The results of the computer analysis appear in map form, and there are also special techniques for finding the optimum route between two points. The data base has been validated by actual vehicle performance measurements.Several recent applications of the Army Mobility Model are discussed. These applications demonstrate that the need for a systematic application of terrain-vehicle research results to vehicle design has been at least partly fulfilled. This simulation technique has developed a stronger communication link between the vehicle designer and user. Establishing this link has created a new demand for a wide variety of vehicle performance predictions for which many predictive relations are not yet fully developed and validated. Adequate research will be necessary to ensure further progress in this direction.