Showing papers by "University of California published in 1992"

Solid phase and combinatorial synthesis of benzodiazepine compounds on a solid support

Abstract: Methods, compositions, and devices for synthesis of therapeutically useful compounds. The invention provides a rapid approach for combinatorial synthesis and screening of libraries of derivatives of therapeutically important classes of compounds such as benzodiazepines, prostaglandins and β-turn mimetics. In order to expediently synthesize a combinatorial library of derivatives based upon these core structures, general methodology for the solid phase synthesis of these derivatives is also provided. This disclosure thus also describes an important extension of solid phase synthesis methods to nonpolymeric organic compounds.

Phase Transitions and Generalized Motion by Mean Curvature

Abstract: We study the limiting behavior of solutions to appropriately rescaled versions of the Allen-Cahn equation, a simplified model for dynamic phase transitions. We rigorously establish the existence in the limit of a phase-antiphase interface evolving according to mean curvature motion. This assertion is valid for all positive time, the motion interpreted in the generalized sense of Evans-Spruck and Chen-Giga-Goto after the onset of geometric singularities.

Building population pharmacokinetic--pharmacodynamic models. I. Models for covariate effects.

Abstract: One major task in clinical pharmacology is to determine the pharmacokinetic-pharmacodynamic (PK-PD) parameters of a drug in a patient population. NONMEM is a program commonly used to build population PK-PD models, that is, models that characterize the relationship between a patient's PK-PD parameters and other patient specific covariates such as the patient's (patho)physiological condition, concomitant drug therapy, etc. This paper extends a previously described approach to efficiently find the relationships between the PK-PD parameters and covariates. In a first step, individual estimates of the PK-PD parameters are obtained as empirical Bayes estimates, based on a prior NONMEM fit using no covariates. In a second step, the individual PK-PD parameter estimates are regressed on the covariates using a generalized additive model. In a third and final step, NONMEM is used to optimize and finalize the population model. Four real-data examples are used to demonstrate the effectiveness of the approach. The examples show that the generalized additive model for the individual parameter estimates is a good initial guess for the NONMEM population model. In all four examples, the approach successfully selects the most important covariates and their functional representation. The great advantage of this approach is speed. The time required to derive a population model is markedly reduced because the number of necessary NONMEM runs is reduced. Furthermore, the approach provides a nice graphical representation of the relationships between the PK-PD parameters and covariates.

Environmental biochemistry of arsenic.

Abstract: Arsenic has both metallic and nonmetallic properties and is a member of the nitrogen family It occurs as a free element and combined form being widely distributed in sulfide ores The poisonous character of arsenic allowed for its use as a herbicide, cattle and sheep dips, and insecticides The ubiquity of arsenic in the environment, its biological toxicity, and its redistribution are factors evoking public concern This review will cover the chemistry of arsenic and methods curently used to speciate the prevalent chemical forms in various environments The major focus of this review is on the biological transformations of arsenic in both the terrestrial and aquatic systems

Measuring the predictive performance of computer-controlled infusion pumps

Abstract: Current measures of the performance of computer-controlled infusion pumps (CCIPs) are poorly defined, of little use to the clinician using the CCIP, and pharmacostatistically incorrect. We propose four measures be used to quantitate the performance of CCIPs: median absolute performance error (MDAPE), median performance error (MDPE), divergence, and wobble. These measures offer several significant advantages over previous measures. First, their definitions are based on the performance error as a fraction of the predicted (rather than measured) drug concentration, making the measures much more useful to the clinician. Second, the measures are defined in a way that addresses the pharmacostatistical issue of appropriate estimation of population parameters. Finally, the measure of inaccuracy, MDAPE, is defined in a way that is consistent with iteratively reweighted least squares nonlinear regression, a commonly used method of estimating pharmacokinetic parameters. These measures make it possible to quantitate the overall performance of a CCIP or to compare the predictive performance of CCIPs which differ in either general approach (e.g., compartmental model driven vs. plasma efflux approach), pump mechanics, software algorithms, or pharmacokinetic parameter sets.

Method and device for retrieving materials from body lumens

Abstract: A retrieval catheter (10) for removing deleterious materials (S) from body lumens comprises an elongate catheter body (12) having a slack net (26) at its distal end (16). The slack net may be collapsed to facilitate introduction into the body lumen and opened in situ to permit capture and retrieval of the deleterious materials. A method for removing ureteral stones from the ureter is described.

People Manipulate Objects (but Cultivate Fields): Beyond the Raster-Vector Debate in GIS

Abstract: The ongoing debate in GIS regarding the relative merits of vector versus raster representations of spatial information is usually couched in technical terms Yet the technical question of the most appropriate data structure begs the philosophical question of the most appropriate conceptualization of geographic space The paper confronts this latter question in the context of the opposition between the “object” and “field” views of space I suggest that GIS can turn a rather dry debate into a source of insights regarding the nature of its subject matter by learning from how people actually experience and deal with the geographic world Human cognition indeed appears to make use of both the object and field views, but at different geographic scales, and for different purposes These observations suggest a list of desiderata for the next round of thinking about spatial representation in GIS

Membrane catalyst layer for fuel cells

Abstract: A gas reaction fuel cell (10) incorporates a thin catalyst layer (22) between a solid polymer electrolyte (SPE) membrane (26) and a porous electrode backing (18). The catalyst layer is preferably less than about 10 νm in thickness with a carbon supported platinum catalyst loading less than about 0.35 mgPt/cm2. The layer (22) is formed as an ink that is spread and cured on a film release blank. The cured film is then transferred to the SPE membrane (26) and hot pressed into the surface to form a catalyst layer (22) having a controlled thickness and catalyst distribution. Alternatively, the catalyst layer (22) is formed by applying an Na+ form of a perfluorosulfonate ionomer directly to the membrane (26), drying the film at a high temperature, and then converting the film back to the protonated form of the ionomer. The layer (22) has adequate gas permeability so that cell performance is not affected and has a density and particle distribution effective to optimize proton access to the catalyst and electronic continuity for electron flow from the half-cell reaction occurring at the catalyst.

Expression of cloned genes in the lung by aerosol- and liposome-based delivery

Abstract: Methods and compositions for producing a mammal capable of expressing an exogenously supplied gene in cells of the airway are disclaimed. Liposome-nucleic acid complexes are prepared then delivered via aerosol to the lung airway. The invention provides a direct method for transforming pulmonary cells as a means for treating disorders of the lung as for providing a means for delivering substances systematically following expression in the lung.

Thermodynamics of multicomponent, miscible, ionic solutions. 2. Mixtures including unsymmetrical electrolytes

Abstract: Model equation for the excess Gibbs energy and solvent and solute activity efficients (given previously for symmetrical salt systems) are here developed for mixtures containing an indefinite number of ions of arbitrary charge, over the entire concentration range. The equations are expressed on a mole fraction basis and comprise a Debye-Huckel term extended to include the effects of unsymmetrical mixing, and a Margules expansion carried out to the fow suffix level

Complex Hunter-Gatherer-Fishers of Prehistoric California: Chiefs, Specialists, and Maritime Adaptations of the Channel Islands

Abstract: The Chumash of the Santa Barbara Channel region were among the most economically and politically complex hunter–gatherer cultures of the New World. In recent decades, rich ethnohistorical documents pertaining to Chumash culture were analyzed, thus providing an excellent foundation for understanding the simple chiefdom that was in place as explorers and missionaries arrived in the sixteenth to eighteenth centuries. Current archaeological research on the Channel Islands focuses on the emergence of ranked society in Chumash prehistory, with special emphasis on political developments and environmental stresses that contributed to cultural evolution. A wide range of data acquired from the Channel Islands illuminates a new model of the rise of complexity. This model of chiefdom emergence is based on population-resource imbalances, political opportunism, and the manipulation of labor by rising elites. Diverse lines of evidence must be employed to evaluate the timing, causes, and consequences of increasing complexity.

Semiconductor nanocrystals covalently bound to solid inorganic surfaces using self-assembled monolayers

Abstract: Methods are described for attaching semiconductor nanocrystals to solid inorganic surfaces, using self-assembled bifunctional organic monolayers as bridge compounds. Two different techniques are presented. One relies on the formation of self-assembled monolayers on these surfaces. When exposed to solutions of nanocrystals, these bridge compounds bind the crystals and anchor them to the surface. The second technique attaches nanocrystals already coated with bridge compounds to the surfaces. Analyses indicate the presence of quantum confined clusters on the surfaces at the nanolayer level. These materials allow electron spectroscopies to be completed on condensed phase clusters, and represent a first step towards synthesis of an organized assembly of clusters. These new products are also disclosed.

Real-space quantum renormalization groups.

Abstract: Although originally thought to show great promise in solving quantum many-body problems on a lattice, numerical real-space renormalization-group techniques have had little success for such problems. We explore the nature of the difficulties involved by studying the applicaton of the method to the simple tight-binding model in one dimension. The standard approach fails dramatically for this model. We show that the key to successfully applying the renormalization-group technique lies in applying a variety of boundary conditions to a block in order to simulate the effect of neighboring blocks.

Capillary rollers and bores

Abstract: A very intriguing phenomenon, which throws much light on the small-scale structure of the sea surface, is the occurrence of “parasitic capillaries” on the forward face of moderately short gravity waves, especially those with wavelengths 5 to 50 cm; see Figure la. These capillary waves were first studied experimentally by Cox (1958). Evidently their existence depends on the fact that a gravity wave and a much shorter capillary wave may have the same phase speed. The dynamical theory of the generation of parasitic capillaries has been developed by Longuet-Higgins (1963), Crapper (1970) and Ruvinsky et al. (1981, 1985, 1991). This so far takes into account only the first-order effects of viscous damping.

A Continuous Media Player

Abstract: The design and implementation of a continuous media player for Unix workstations is described. The player can play synchronized digital video and audio read from a file server. The system architecture and results of preliminary performance experiments are presented.

Cognitive, life stress, and interpersonal approaches to a developmental psychopathology model of depression

Abstract: One pathway to depression in children and adults is hypothesized to result from complex transactions among cognitive, stress, and interpersonal variables. Cognitive vulnerability includes not only appraisals of events and circumstances that emphasize personal unworthiness and incompetence, but also underlying beliefs and “working models” of the self and others. Such cognitions arise in part in the context of maladaptive attachment relations with the parents and may be reinforced by interpersonal incompetencies and difficulties in peer, family, and social relationships. Stressful conditions in early life and throughout development may undermine or erode the development of effective coping competencies. Moreover, maladaptive cognitions about the self and others, and ineffective coping competencies, may contribute to the occurrence of stressful events and circumstances —and these in turn may trigger depressive reactions. For many depressed people with chronic or recurrent depression, therefore, developmental processes play critical roles in the origin and continuation of the disorder.

Can Wage Increases Pay For Themselves? Tests with a Productive Function

Abstract: Efficiency wage theories predict that companies that pay high wages will have higher productivity from high work effort, low turnover, and other efficiency-enhancing effects. This paper uses the PIMS line-of-business data set to test whether high wage businesses are more productive. Relative wages were measured by managers' assessments of their relative compensation, holding worker quality constant. A positive relation was found between changes in relative wages and changes in total factor productivity. The elasticity of output with respect to wages was of the magnitude predicted by efficiency wage theories. Also consistent with efficiency wage theories, the relationship between changes in wages and changes in productivity was weaker at businesses with high unionization. Results from two additional data sets imply that high wages are not merely measuring high human capital. Copyright 1992 by Royal Economic Society.

Accurate Singular Values and Differential QD Algorithms

Abstract: In September 1991 J. W. Demmel and W. M. Kahan were awarded the second SIAM prize in numerical linear algebra for their paper ‘Accurate Singular Values of Bidiagonal Matrices’ [1], referred to as DK hereafter. Among several valuable results was the observation that the standard bidiagonal QR algorithm used in LINPACK [2], and in many other SVD programs, can be simplified when the shift is zero and, of greater importance, no subtractions occur. The last feature permits very small singular values to be found with (almost) all the accuracy permitted by the data and at no extra cost.

Apparatus and method for spectroscopic analysis of scattering media

Abstract: Apparatus and method for spectroscopic analysis of scattering media. Subtle differences in materials have been found to be detectable from plots of intensity as a function of wavelength of collected emitted and scattered light versus wavelength of excitation light.

The growth of Cu-Sn intermetallics at a pretinned copper-solder interface

Abstract: This article reports a comparative study of the formation and growth of intermetallic phases at the interface of Cu wetted with a thick solder joint or a thin, pretinned solder layer The η phase (Cu6Sn5) forms when Cu is wet with eutectic solder at temperatures below 400 °C The intermetallic layer is essentially unaffected by aging at 70 °C for as long as 13 weeks On aging a eutectic joint at 170 °C, the η-phase intermetallic layer thickens and e phase (Cu3Sn) nucleates at the Cu/intermetallic interface and grows to a thickness comparable to that of the η phase, while a Pb-rich boundary layer forms in the solder The aging behavior of a thin, pretinned eutectic layer is qualitatively different At 170 °C, the Sn in the eutectic is rapidly consumed to form η-phase intermetallic, which converts to e phase The residual Pb withdraws into isolated islands, and the solderability of the surface deteriorates When the pretinned layer is Pb-rich (95Pb-5Sn), the Sn in the layer is also rapidly converted into η phase, in the form of dendrites penetrating from the intermetallic at the Cu interface and discrete precipitates in the bulk How ever, the development of the intermetallic largely ceases when the Sn is consumed; e phase does not form, and the residual Pb remains as an essentially continuous layer, preserving the solderability of the sample These observations are interpreted in light of the Cu-Sn and Pb-Sn phase diagrams, the temperature of initial wetting, and the relative diffusivities of Cu and Sn in the solder and intermetallic phases

Visible light emitting diodes fabricated from soluble semiconducting polymers

Abstract: Visible light LEDs are produced having a layer of conjugated polymer which is cast directly from solution or formed as a gel-processed admixture with a carrier polymer The LEDs can be formed so as to emit polarized light

Method and apparatus for multiplexing communications signals through blind adaptive spatial filtering

Abstract: A method and apparatus for spatial multiplexing of spectrally overlapping communications signals which does not require use of a training signal, computationally intensive direction-finding methods, or antenna calibration is presented. An adaptive antenna array at a base station is used in conjunction with signal processing through self coherence restoral to separate the temporally and spectrally overlapping signals of users that arrive from different specific locations within the locale and to mitigate multipath fading and shadowing at the base station and, by reciprocity, to transmit directively to minimize interfering signals arriving at the mobile (or portable or stationary) units and to mitigate multipath fading and shadowing at the mobile units. The radiation pattern of transmitted signal is matched to the adapted reception pattern of the signal received at the base station. BACKGROUND OF THE INVENTION The Government has rights in this invention pursuant to Grant No. MIP-88-12902 awarded by the National Science Foundation.

Macrophage-derived growth factors.

Abstract: In the early decades of the twentieth century biologists sought to grow cells in culture. Clotted blood was found to contain molecules that accomplished this purpose (Carrel 1912), but only later did biochemists seek to purify these molecules. By the middle of the century, biochemists and biologists sought to explain neonatal eye opening in mice in molecular terms (Cohen 1987; Levi-Montalcini 1987). Each of these goals ultimately led to the isolation of single species of molecules called growth factors by using in vitro or in vivo bioassays for growth and a biochemical algorithm for isolation. Epidermal growth factor (EGF), nerve growth factor (NGF), platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), interleukin-1 (IL-1), and macrophage colony-stimulating factor (M-CSF, or CSF-1) were isolated and directly sequenced or molecularly cloned (based on partial sequences) by these means in the 1970s and early 1980s. The production of transformed foci of cells by introduction of fragments of cloned transcripts or genes from tumors also produced a subclass of oncogenes that turned out to be growth factors [c-sis, or PDGF-B chain, and Kaposi’s sarcoma-fibroblast growth factor (kFGF, or FGF-4)]. Most recently, the formation of tumors in vivo after random integration of a highly active viral promoter upstream of cellular genes has produced the int-1 and int-2 (also known as FGF-3) growth factors. Finally, after the founding member of a growth factor family is identified with a bioassay, low-stringency cDNA library screens and polymerase chain reaction can be used to complete the family (JAKOWLEW et al. 1988; HEBERT et al. 1990). All growth factors are operationally isolated and defined by their ability to cause growth, but may also act as nonmitogenic inflammatory factors.

Fatal cerebral hemorrhage due to autonomic dysreflexia in a tetraplegic patient: case report and review

Abstract: Autonomic dysreflexia is the most important specific complication of high level spinal cord injury both in tetraplegic and in paraplegic patients above the midthoracic neural segment. It is a life threatening emergency that may lead to apoplexy. We present a case of fatal cerebral hemorrhage due to autonomic dysreflexia in order to demonstrate the gravity of this particular syndrome.

Aligned wafer bonding

Abstract: A process for precision alignment and bonding of complementary micromechanical, electrical and optical structures. Surface features of the structures are critically aligned and brought into physical contact within atomic dimensions to form direct bonds without the use of adhesives. The bonds are initially formed at room temperature and then strengthened by a high temperature anneal. Three dimensional structures may be formed in separate prefabricated layers rather than monolithically through the use of this process.

Transfection of lung via aerosolized transgene delivery

Abstract: Methods and compositions for producing a mammal capable of expressing an exogenously supplied gene in cells of the airway are disclosed. Lipid carrier-nucleic acid complexes are prepared then delivered via aerosol to the lung airway. The invention provides a direct method for transforming pulmonary cells as a means for treating disorders of the lung as for providing a means for delivering substances systematically following expression in the lung.

Fieldwork in developing countries

Abstract: Part 1 Overview - fieldwork from start to finish: the context of fieldwork issues of data collection. Part 2 Case studies - fieldwork experiences in Africa and Asia: observers are worried random sampling and repeat surveys in South India fieldwork under time constraints qualitative research - collecting life stories field methods for economic mobility sensitive information talking to traders about trade fieldwork in a familiar setting facts or fictions - fieldwork relationships and the nature of data thinking about the ethics of fieldwork contrasts in village-level fieldwork - Africa and India.

Flavonoids: Plant Signals to Soil Microbes

Abstract: Recent discoveries have established that some flavonoids and several simple phenolics function as transcriptional signals from plants to bacteria. These findings open an important new chapter for understanding plant—microbe interactions and offer a potentially powerful intellectual foundation for analyzing factors controlling rhizosphere ecology.

The Construction of Optimal Linear and Nonlinear Regulators

Abstract: The regulator servomechanism problem is to design a feedforward and feedback control law to make the output of a given system called the plant, track a signal from a given class. There are various ways to make this precise, we shall follows Francis [5] and Isidori and Byrnes [11]. The class of signals to be tracked are described as the output of a second system called the signal generator (or exosystem). The control law consists of feedforward terms involving the state of signal generator, feedback terms involving the state of the plant and mixed terms involving both.

Supercapacitors based on carbon foams

Abstract: A high energy density capacitor incorporating a variety of carbon foam electrodes is described. The foams, derived from the pyrolysis of resorcinol-formaldehyde and related polymers, are high density (0.1 g/cc-1.0 g/cc) electrically conductive and have high surface areas (400 m2/g-1000 m2/g). Capacitances on the order of several tens of farad per gram of electrodes are achieved. The preferred embodiment capacitor has two cells. In the upper cell (10), a solder-wettable layer (32) and an adhesive metal layer (30) overlie an electrode (22). An electrode separator (40) lies between electrode (22) of the upper cell (10) and electrode (26) of the upper cell (10). Solder-wettable layer (36) and adhesive layer (34) overlie electrode (26). A similar electrode (26) is shown in lower cell (12), with adhesive layer (34) and solder-wettable layer (36) formed thereon. A cell separator (24) lies between electrode (22) of cell (10) and electrode (26) of cell (12).