A previously described synthetic method was modified to improve the porosity of the alumina product. The compound (Et2AlNH2)(3) was prepared from ammonia and triethyl-aluminum (Et3Al) in toluene solvent. Addition of acetone to form a solution of ethylaluminoxane (EtAlO) and acetonine (2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine) was followed by addition of two equivalents of water to give an alumina precursor. Alumina precursors also were prepared by the direct hydrolysis of (Et2AlNH2)(3). Powder X-ray diffraction, Al-27 MAS NMR, and N-2 adsorption/desorption isotherms were used to analyze the aluminas after calcination of the precipitates. The aluminas exhibited high pore volume and surface area, and they were amorphous after calcination at 500 degreesC. One alumina showed a significant fraction of pentacoordinate aluminum after heating to 300 degreesC in air or 500 degreesC in steam atmosphere. The products crystallized as alpha-Al2O3 at the low temperature of 1000 degreesC, which reduces their applicability for catalysts. Synthesis variables and their effects on alumina properties are discussed.

The metabolites of the antipsychotic drug trifluoperazine (TFP) were investigated with on-line coupling of high-performance liquid chromatography (HPLC) and NMR spectroscopy. A chromatographic method was developed using a reversed-phase C-30 silica gel column. Rats were given a cumulative dose of 90 mg kg(-1) TFP dihydrochloride and samples of brain and muscle tissues were extracted after 29 h. The peaks obtained on chromatographic separation were assigned to trifluoperazine and its metabolites. With the help of chromatograms obtained from test mixtures, 1D and 2D HPLC-NMR were used to identify the peaks found for these mixtures. Copyright (C) 2000 John Wiley & Sons, Ltd.

In this article we discuss a new method to detect possible nonlinear structure in signals obtained from dynamical systems, which includes those obtained from physiological systems. The sampled discrete time series is first mapped onto a phase space by the method of delays. The vector series in phase space is partitioned into a finite number of clusters by the k-means technique. The determinant of the within class scatter matrix provides an estimate of the hyper-ellipsoidal volume of the partitioned phase space. The objective is to observe for significant difference in the hyper-ellipsoidal scatter volume between the original data and its corresponding surrogate realizations. The surrogate data sets were generated by the iterated Amplitude Adjusted Fourier Transform technique (IAAFT). The null hypothesis addressed here is that the original data is a static nonlinear transform of a linearly correlated noise. The data sets analyzed include the uterine electromyography obtained during active labor.

Localized in vivo proton magnetic resonance spectroscopy at 4.7 T was used to examine the brains of rats that were given the antipsychotic drugs haloperidol, clozapine, or olanzapine for 1 week. Spectra were collected before and during treatment. The ratios of N-acetylaspartate (NAA) to creatine (Cr) and choline to Cr were determined from the spectra. No significant differences in these ratios were seen among the rats given the various antipsychotic medications or between the control rats and the treated rats. No significant time-dependent changes were seen in most cases, except for a small reduction of NAA/Cr after 7 days of olanzapine administration. These results suggest that differences in brain metabolite ratios in vivo in schizophrenics relative to controls, at least for short-term treatment, arise from the disease, and not as a metabolic effect of the medication. (C) 2000 Wiley-Liss, Inc.

Fluorine-19 NMR spectra were acquired from extracts of tissues from heads of rats given the antipsychotic drug trifluoperazine (TFP). Contributions to the in vivo 19F spectra from tissues other than brain were negligible. The in vivo 19F resonance at -62.3 ppm from CCl3F consisted of 6–8 resolved resonances in vitro. Some in vitro resonances were assigned to previously identified TFP metabolites. Multiple resonances in vitro partially explain the relatively large line width seen in vivo for TFP. Unidentified metabolites were observed at about -74 to -75 ppm in a number of spectra of extracts of brain and muscle. Magn Reson Med 43:756–759, 2000. © 2000 Wiley-Liss, Inc.

A three probe potentiostat was used to control the potential to a catalytic ruthenium oxide anode in oxidation studies of 2,2′-dichlorobiphenyl (2,2′). Voltages applied varied in one volt increments from 2.0 to 4.0 volts. Studies involved determination of the optimum voltage operating in conjunction with added sodium persulfate oxidizers (0.002 M and 0.018 M) and various exposure times (1 and 8 h) to ultra-violet (254.7 nm) provided by a General Electric BH-6 high pressure mercury arc lamp. The oxidation products of 2,2′ consisted of four compounds. The primary product was 2-chloro, 2′-hydroxyl biphenyl. Other products included: 2-acetoxy, 2′chlorobiphenyl (as previously observed by Laule et al, Journal of Electroanalytical Chemistry, 213: 329–332 (1986)), and dibenzofuran and 5,5′ dichlorodibenzofuran. All products were confirmed using a combination of GC and GC/MS. No reduction in 2,2′ concentration was observed in any of the control solutions in the absence of an applied voltage. Additionally, the presence of an oxidizer and UV irradiation aided the oxidation of 2,2′-dichlorobiphenyl. The oxidation percentage of the 2,2′ at 5 ppm was in the range of 70% under the optimum conditions of applied potential (3.0 volts), persulfate concentration (0.018 M), and UV exposure time (8 h). All reaction conditions and analysis procedures are described.

Twotechniques commonly used on human magnetic resonance spectroscopy systems to obtain spectra from localized volumes in the brain are point resolved spectroscopy (PRESS) and stimulated echo acquisition mode (STEAM)spectroscopy. PRESS gives a signal twice as large as that obtained withSTEAM, but suffersfromlonger minimum echo times. WhileSTEAM must be used to detect species withshortspin-spin relaxation times, PRESS can be used forspecies with longer relaxation times to give a spectrum with a better signal to noise ratio. Only STEAMwas provided for the GE Omega 4.7 T smallanimalimager used in this laboratory. Therefore, a PRESS pulse program was written for this instrument. With the standard sequence, the sampled voxel is smaller than the prescribedvoxel. A larger voxel can be prescribed to increase the sampled volume. A different approach, involving the modification of the gradient strength, has been used in this laboratory. The resulting pulse sequence, with representative profiles, is discussed.

Large grained (> 50 mu m < 100 mu m) polycrystalline silicon films have been formed using a patented electrostatic deposition method which utilizes charged particle motion in an electric field. After deposition, the films are heat treated at varying times and temperatures in a programmable furnace maintained under a purified argon atmosphere. Solar cells were fabricated using these large grained polycrystalline silicon films by sputtering pure gold as back contacts and using high quality silver paint as front contacts. The cells have shown efficiencies of 1.8% indicating that great potential exists for significant improvement.

Thin films of silicon have been formed using a patented electrostatic deposition method whichutilizes charged particle motion in an electric field.After deposition, the films are heat treated for varying times and temperatures in a programmable furnace maintained under a purified argon atmosphere. X-ray diffraction (XRD) confirmed that these films were polycrystalline in nature. These films were found to have grain sizes of about 50 microns. Solar cells were fabricatedusing theselargegrained polycrystalline silicon filmsby sputtering pure gold as both front and back contacts. The cellshave shown efficiencies of 1.8%.This paper reports on the growth of these large-grained polycrystalline thin silicon films and on the laser recrystallization setup to be used to increase the grain size up to 100 microns. Films grown via this electrostaticdeposition method and subsequent laser recrystallization have a great potential for use in the solar cell industry.

RIF tumors implanted on mice feet were investigated for changes in relaxation times (T1 and T2) after photodynamic therapy (PDT). Photodynamic therapy was performed using Photofrin II as the photosensitizer and laser light at 630 nm. A home-built proton solenoid coil in the balanced configuration was used to accommodate the tumors, and the relaxation times were measured before, immediately after, and up to several hours after therapy. Several control experiments were performed untreated tumors, tumors treated with Photofrin II alone, or tumors treated with laser light alone. Significant increases in T1s of water protons were observed after PDT treatment. In all experiments, 31P spectra were recorded before and after the therapy to study the tumor status and to confirm the onset of PDT. These studies show significant prolongation of T1s after the PDT treatment. The spin-spin relaxation measurements, on the other hand, did not show such prolongation in T2 values after PDT treatment.

Tin oxide (SnO2) is one of the most popular metal oxide semiconductors used as a gas sensor. Commercial sensors that use tin oxide are inexpensive and readily available. Computer controlled thermal cycling techniques were used with only one sensor to collect a series of conductance surfaces for various compounds versus concentration. These patterns were treated as inputs to a neural network program that was trained to associate particular patterns to a specific compound. When the neural network was successfully trained to recognize pure patterns, the network was presented with a conductance pattern from a combination of compounds to test if the neural network could identify the constituents. This analysis method allowed the qualitative recognition of the different gases in a mixture or in one single gas. The results using a one sensor approach for the neural network identification of methanol, isopropanol, and hexane are presented and discussed. This, to our knowledge, is the first attempt to use data from a single sensor and process it via a neural network program to identify gases found in process environments.

Invivo 31P NMR studies recently have shown that cocaine causes an imbalance of the free magnesium in the brain which results inpH lowering, ischemia, and even death. This direct interaction with the free Mg+2 in the brain also affects the Ca+2 balance which controls arterial and vascular contraction. This research has addressed the mechanism of the cocaine interaction with magnesium adenosine 5-triphosphate (ATP) using 31P, 13C, and 1HNMRusing a Bruker 200 MHz nuclear magnetic resonance (NMR) system. Data are presented and discussed which shows that cocaine and ATP form a complex species which directly affects the NMRspectra.

The objective of this paper is to discuss the complexity of fetal movement detection encountered during development and implementation of an automated single Doppler ultrasonic transducer based instrument. The single transducer instrument was intended to better quantify the duration, velocity, and magnitude of fetal movements. A Corometrics Model 116 fetal heart rate monitor was modified, and a fetal movement detection algorithm (Russell Algorithm) was developed to detect fetal movements on one and two (data fusion) transducers. A Hewlett-Packard (HP) M-1350-Afetal monitor and the Russell Algorithm were used to detect and record fetal movements concurrently on sixty patients between the gestation ages of 31 to 41 weeks. Using a computer-controlled SVHS PC-VCR, the instrumental detection of fetal movements was time-linked with real-time video ultrasound. This allowed the fetal movements to be scored by expert examiners on a second-per-second basis. A total of 52,478 seconds of fetal movements was scored using this system. Neither system could accurately define the entire duration, velocity, or magnitude of the fetal movements as detected by real-time ultrasound. The complexity of detecting fetal movements using only one transducer has many shortcomings, such as: the amplitude of the returning Doppler signal, the small area of the fetus monitored by a single transducer, the position of the fetus, the type and variety of fetal movements, and material size and shape.

Thin film synthetic diamond promises to be the next semiconductor material, if the manufacturing processes which produce it can be controlled. Solid state nuclear magnetic resonance (NMR)using magic angle spinning (MAS)is used to measure the content of hydrogen in diamond whichcontrols the resistivity of the diamond thin films. Spectral results are presented for proton NMR of thin film synthetic diamond. Experimental calibration techniques using BaF 2 as the hydrogen standard willbe discussed, as wellas acquisition times, pulsing sequences, spinning rates, and rotor composition.

Cryostats which are currently used to characterize the properties of superconductors between 4 K and 100 K are primar- ily single sample devices. The purpose of this paper is to present an instrument design which can hold up to five (5) one cm. diameter samples at a stable temperature (+ 0.1 K) within the above range specified while measurements of the sam- ple properties are made.

We have examined the changes in the 31P NMR chemical shifts of ATP in aqueous solution, upon addition of NaCl and LiCl at ambient temperature. NaCl and LiCl cause qualitatively similar downfield changes, although the effect of LiCl is somewhat larger. For a 2:1 mixture of Na-ATP or tris-ATP and MgCl2 at 0°C, separate beta-P peaks are observed for uncomplexed ATP and ATP complexed with Mg(II) at 121.6 MHz. Addition of LiCl slightly shifts the uncomplexed Na-ATP or tris-ATP peak downfield but does not measurably shift the Mg-ATP peak or change relative intensities. Thus, Li behaves more like Na than Mg in its ATP complexation behavior, making this system a poor model for competition between Li and Mg for macromolecular binding.

The double-quantum behavior of 23Na in the presence of different concentrations of Li in human erythrocytes was investigated. The 23Na double-quantum signal was quenched in both the extracellular and the intracellular compartments with increasing concentration of Li in each compartment, along with an increase in the 23Na T1 both intra- and extracellularly. Some extracellular quenching could be observed at the near therapeutic concentration of 2 mM Li. The ratio of slow to fast spin-spin (T2) relaxation times, obtained from the dependence of the double-quantum signal on creation time, approached unity at an overall Li concentration of 40 mM. These results provide evidence that Li and Na compete for both intra- and extracellular binding sites in erythrocytes.