cssi/SciSciGPT-SciSciNet huggingface dataset:
Identification of oxidation products of solanesol produced during air sampling for tobacco smoke by electrospray mass spectrometry and HPLC

Solanesol, a 45-carbon, trisesquiterpenoid alcohol found in tobacco leaves and tobacco smoke, has been used as a quantitative marker for tobacco smoke for years. However, solanesol appears to be unreliable as a quantitative marker for tobacco smoke during environmental air sampling because it can be degraded substantially when present as a component of tobacco smoke and by as much as 100% when present as pure solanesol on fortified filters during air sampling. Since there is strong evidence that ozone is the agent responsible for the degradation, solanesol appears to be unreliable as a quantitative marker during indoor air sampling when indoor levels of ozone are greater than about 15 ppb. The degree of loss of pure solanesol is directly proportional to the concentration of ozone and the length of the sampling period and depends on the type of 37 mm membrane filter used for air sampling (PTFE or quartz fiber). While the degree of loss of solanesol is inversely proportional to the relative humidity of the air at a sampling rate of 1.7 L min−1, the degree of loss is virtually independent of relative humidity at a lower sampling rate; i.e., 0.25 L min−1. A curve of loss of solanesol on a filter versus concentration of ozone from an ozone generator is virtually identical to a curve segment based on atmospheric ozone under the same conditions of air sampling. Oxidation of solanesol by ozone to approximately 25 to 60% completion produces at least three series of products for a total of at least 26 compounds: (1) isoprenoid acetones, (2) ω-hydroxyisoprenoid acetaldehydes, and (3) isoprenoid oxoaldehydes. All products in each series were tentatively identified as their derivatives with 2-(p-aminophenyl)ethanol (APE) by electrospray mass spectrometry (ES-MS). Ten ozonation products were detected as their 2,4-dinitrophenylhydrazine derivatives by HPLC at 360 nm: 4-oxopentanal and nine isoprenoid acetones (acetone, 6-methyl-5-hepten-2-one, geranylacetone, farnesylacetone, tetraprenylacetone, geranylfarnesylacetone, farnesylfarnesylacetone, farnesylgeranylgeranylacetone and bombiprenone.
A structure-based model of semantic integrity constraints for relational data bases

Data base management systems (DBMSs) are in widespread use because of the ease and flexibility with which users access large volumes of data. Ensuring data accuracy through integrity constraints is a central aspect of DBMS use. However, many DBMSs still lack adequate integrity support. In additon, a comprehensive theoretical basis for such support the role of a constraint classification system - has yet to be developed. This paper presents a formalism that classifies semantic integrity constraints based on the structure of the relational model. Integrity constraints are characterized by the portion of the data base structure they access, whether one or more relations, attributes, or tuples. Thus, the model is completely general, allowing the arbitrary specification of any constraint. Examples of each type of constraint are illustrated using a small engineering data base, and various implementation issues are discussed.
The Public Discourse of the Corporate Citizen

The discursive responsibilities of citizenship demand a dialogic mode of corporate behavior characterized by demonstrations of respect, commitment, and exposure. Issues management that integrates strategic business goals with dialogic public communication efforts will better meet the discursive requirements of full membership in civil society.
Macrocyclic Design Strategies for Small, Stable Parallel β-Sheet Scaffolds

Pairs of short peptide strands can be induced to adopt an antiparallel beta-sheet secondary structure in aqueous solution via a macrocyclic constraint, as illustrated by many natural and designed peptides. We show that an analogous strategy is successful for creation of small units of parallel beta-sheet secondary structure in aqueous solution. Cyclization in this case requires nonpeptide segments for N-to-N and C-to-C interstrand linkage. Surprisingly, we find that only one of these segments needs to be preorganized.
Minimisation of unbalanced and reactive currents in three-phase asymmetrical circuits with nonsinusoidal voltage

Asymmetry of three-phase loads causes deterioration in the power factor and power quality of a circuit. Waveform distortion aggravates these unfavourable effects even more. A method of improving the power factor and the loading symmetry in a three-phase unbalanced circuit under nonsinusoidal conditions is presented. The method discussed is based on the source current orthogonal decomposition into the active, scattered, unbalanced, and reactive components, developed for three-phase asymmetrical systems. The author shows that this current decomposition provides the fundamentals for the design of passive compensators which can effectively reduce the unbalanced and reactive components of the source current under nonsinusoidal conditions. >
Intraseasonal Modulation of the North Pacific Storm Track by Tropical Convection in Boreal Winter

Abstract The modulation of the North Pacific storm track by tropical convection on intraseasonal time scales (30–90 days) in boreal winter (December–March) is investigated using the NCEP–NCAR reanalysis and NOAA satellite outgoing longwave radiation (OLR) data. Multivariate empirical orthogonal function (MEOF) analysis and case compositing based upon the principal components (PCs) of the EOFs reveal substantial changes in the structure and intensity of the Pacific storm track quantified by vertically (925–200 mb) averaged synoptic eddy kinetic energy (SEKE) during the course of a typical Madden–Julian oscillation (MJO) event. The storm-track response is characterized by an amplitude-varying dipole propagating northeastward as the center of the anomalous tropical convection moves eastward across the eastern Indian Ocean and the western-central Pacific. A diagnosis of the SEKE budget indicates that the storm-track anomaly is induced primarily by changes in the convergence of energy flux, baroclinic conversi...
Electrophoretic profiling of both RNA and protein from a single 250-pL sample.

A novel approach is described that uses capillary electrophoresis (CE) to electrophoretically sample and separate both protein and RNA from a single injected plug of cell lysate. A 250-pL sample of lysate from Chinese hamster ovary cells (9.6 × 107 cells/mL) was hydrodynamically injected into a capillary containing a Tris-based aqueous buffer. This was followed by selective electrokinetic ejection of RNA from the lysate into water, yielding an effective cell concentration of RNA of 3000 cells/mL. The cellular components (e.g., proteins) retained in the capillary were separated and then detected with laser-induced fluorescence (LIF) using 275-nm excitation. The ejected/diluted sample was subsequently injected into a separate CE-LIF system, which utilized an entangled polymer sieving matrix and 543-nm excitation for the detection of ethidium bromide-labeled nucleic acids (i.e., RNA). Virtually no sample preparation is required other than simple washing and lysing of the cells isolated from culture. This com...
Occurrence of Candida albicans in Infections of Endodontic Origin

Microorganisms are recognized as the etiological agent for the majority of pulpal and periradicular disease. Although bacteria have been the most studied, fungi have also been associated with infected root canals. The purpose of this study was to evaluate the contents of infected root canals and aspirates of cellulitis/abscesses of endodontic origin for the presence of Candida albicans using the polymerase chain reaction (PCR). PCR primers specific for the 18S ribosomal RNA gene of C. albicans were used to survey 24 samples taken from infected root canals and 19 aspirates from periradicular infections of endodontic origins. The presence of C. albicans was detected in 5 of 24 (21%) samples taken from root canals, but none was detected in the periradicular aspirates. The results indicate that PCR is an extremely sensitive molecular method that may be used to identify C. albicans directly in samples from infections of endodontic origin.
High prevalence of multiple micronutrient deficiencies in children with intestinal failure: a longitudinal study.

Objective To determine the prevalence of micronutrient deficiencies in children with intestinal failure as they transitioned from parenteral nutrition (PN) to enteral nutrition (EN).
Structural and Chemical Characterization of Aligned Crystalline Nanoporous MgO Films Grown via Reactive Ballistic Deposition

Highly porous (∼ 90%), high-surface area (∼1000 m2/g), thermally stable (1200 K) crystalline films of MgO are synthesized using a novel reactive ballistic deposition technique. The film consists of a tilted array of porous nanoscale crystalline filaments. Surprisingly, the individual filaments exhibit a high degree of crystallographic order with respect to each other. These films have chemical binding sites analogous to those on MgO(100). However, the fraction of chemically active, high energy binding sites is greatly enhanced on the nanoporous film. This unique collection of properties makes these materials attractive candidates for chemical applications such as sensors and heterogeneous catalysts.
Role of ventricular assist therapy for patients with heart failure and restrictive physiology: Improving outcomes for a lethal disease

Background Restrictive cardiomyopathy (RCM) patients have poor prognosis due to progressive heart failure characterized by impaired ventricular filling of either or both ventricles. The goal of this study was to evaluate the outcome of end-stage RCM patients after left ventricular assist device (LVAD) implantation and to determine factors that may be associated with improved survival. Methods This investigation is a retrospective study of prospectively collected data that include 28 consecutive patients with end-stage RCM who received continuous-flow LVADs at the Mayo Clinic, Rochester, Minnesota. Outcome was assessed by survival with LVAD support until heart transplantation or all-cause mortality. Results The mean follow-up time post-LVAD implantation was 448 ± 425 days. The mean hospitalization time was 29 ± 19 days and was complicated mainly by post-operative right ventricular (RV) failure requiring short-term medical support. The short-term in-hospital mortality was 14%. Ten patients underwent heart transplantation with 100% survival post-transplant during the follow-up period. One-year survival for patients with LVADs without transplantation was 64%, and was not significantly different between amyloidosis and non-amyloidosis patients. Larger left ventricle (LV) end-diastolic and end-systolic dimensions were significantly associated with improved survival rates (RR = 0.94 and 0.95, p Conclusions LVAD is a feasible, life-saving therapy for end-stage heart failure related to RCM, especially as a bridge to transplant and in patients with larger LV dimensions.
The Effects of Task and Interpersonal Cohesiveness on Performance of a Disjunctive Group Task1

This experiment examined the effects of two different types of group cohesiveness on performance of a disjunctive task. Both interpersonal and task cohesiveness were varied independently. Results show that high levels of both types of cohesiveness were necessary for success on a task requiring group interaction. Groups high on one type of cohesiveness but low on another performed no better than groups low on both types of cohesiveness. These results suggest that cohesiveness should be conceptualized as a multidimensional rather than as a unitary variable. It is also suggested that the effects noted in the present study may well vary according to task characteristics.
Transformation of different phenotypic types of human bone marrow T-lymphocytes by HTLV-1

Fresh bone marrow mononuclear leukocytes were used as a target for infection by human T-cell leukemia-lymphoma virus subgroup 1 (HTLV-1) by co-cultivation with virus-positive cell lines. The lines were established from T-cell leukemia-lymphoma patients or HTLV-1-transformed human umbilical cord-blood T cells. Clumps of transformed cells became visible by 2-3 weeks after infection and developed at a high frequency (greater than 90%) in the bone marrow samples used. Stimulation of target cells with lymphocyte mitogens facilitated this process but was not absolutely required. Unlike fresh or cultured cells from HTLV-1-positive adult leukemia-lymphoma patients and HTLV-1-transformed cord-blood T cells, which usually have an OKT 4/leu 3a surface phenotype, the transformed bone marrow cells frequently fell into one of three categories based on their reactivity with cell-specific monoclonal antibodies. These included populations of cells that were predominantly; (1) OKT 4/leu 3a-positive, (2) OKT 8/leu 2a-positive, and (3) cells expressing neither phenotype. Fresh bone marrow provided a rapid and efficient system for the assessment of HTLV-1 infection. The type of bone marrow cells transformed in vitro suggests that HTLV-1 can infect several subsets of T lymphocytes, possibly including immature cells or that these cells can undergo phenotypic modulation.
Discriminative stimulus effects of ethanol in rats using a three-choice ethanol-midazolam-water discrimination.

Three-choice discrimination procedures are used to characterize how similar the discriminative stimulus effects of two drugs are in relation to each other. This procedure has suggested similarities between ethanol and ligands that positively modulate the γ-aminobutyric acid type A (GABA A ) receptor complex. As an extension to these studies, male Long-Evans rats were trained to discriminate midazolam (3.0mg/kg, i.p.) from ethanol (1.0g/kg, i.g.) from water (2.3 ml, i.g.) in a three-lever, food reinforced task. Substitution tests were conducted following administration of GABA A -positive modulators, noncompetitive N-methyl-D-aspartate (NMDA) antagonists, 5-HT 1 B agonists and isopropanol. Among the GABA A -positive modulators, diazepam was the only drug that completely substituted for midazolam; both pentobarbital and the neurosteroid allopregnanolone showed partial midazolam substitution. The NMDA antagonist dizocilpine substituted for ethanol, while phencyclidine showed no substitution for either ethanol or midazolam. The serotonin agonists tested also showed no substitution for either ethanol or midazolam. Isopropanol was the only other drug that completely substituted for ethanol. These data extend previous findings from an ethanol-pentobarbital-water discrimination and further define training conditions that result in a conditional basis for the ethanol discrimination where only those drugs with pharmacological heterogeneous effects similar to ethanol produce a full ethanol-like effect.
Isozyme- and gender-specific induction of glutathione S-transferases by flavonoids

Most dietary flavonoids have antioxidant activity in vitro however, secondary mechanisms such as the ability to influence gene expression with the consequent modulation of specific enzymatic activities involved in the intracellular response against oxidative stress, are being realized. In the following study, we examined the ability of the flavonoids: flavone, morin, naringenin, (+)-catechin, and quercetin to modulate the activity of glutathione S-transferases (GSTs) mGSTA, mGSTP and mGSTM in hepatic tissues of male and female Swiss Webster mice. Subchronic dietary exposure to morin, naringenin, (+)-catechin, and quercetin (2,500 mg/kg diet for 20 days) did not produce statistically significant changes in GST activity. Conversely, gender-, and isozyme-specific induction of mGSTs were observed in animals fed flavone. A sevenfold increase in total mGST activity was observed in female animals whereas a fourfold increase was observed in male animals. Enzyme specific assays indicate that there were greater increases of both mGSTM (eightfold) and mGSTP (fourfold) activities in females as compared to males (sixfold and twofold, respectively). As testosterone is involved in the regulation of GSTs in mice, castrated males were fed flavone for 5 days (2,500 mg/kg diet). In this case, dietary flavone resulted in similar fourfold increases in total GST activity in inact and castrated animals. Isozyme specific studies indicate that increases could be attributed to an induction of mGSTM and mGSTP.
Ward information-management system—An evaluation

Abstract A computerized ward information-management system was developed and implemented at the Johns Hopkins Hospital on one medical floor. To determine its effectiveness, a rigorous evaluation effort was conducted. The evaluation was designed to monitor the effects of the system on patient care by hospital nursing personnel. Likewise, the costs and cost benefits of the incremental expenditures of the system were measured. The results of this evaluation effort showed that the system caused significant changes in personnel work patterns, in that direct patient-care activities increased materially. Errors in carrying out physicians' orders were significantly decreased. Further the evaluation efforts indicated that the costs of the system should be effectively offset by improved staff effectiveness. The system seems to have the potential to help identify those personnel cost savings available if reduced hospital expenses becomes the objective. If the decision is to increase the efficacy of treatment given in the hospital, the ward information-management system seems to provide the ability to improve care on a constant basis without personnel increases.
Whose book is this?: Authorial versus editorial control of Harriet Brent Jacobs' Incidents in the life of a slave girl: Written by herself

Abstract The recent surge of critical interest in autobiography, leads us to rethink all of our assumptions about this genre. In particular, Jeffery Melhman's and Germaine Bree's ideas on the significance of the act of writing to the autobiographer's gradual self-discovery, help us to understand the peculiar questions of authenticity surrounding the nineteenth century American collaborative slave narrative. Following a brief discussion of American abolitionists' rules governing the format and publication of American slave narratives, this article examines some of Harriet Brent Jacobs' letters to Amy Post in which she explains why and how she wrote her life story. It is then argued that the manner in which the abolitionist Lydia Maria Child edited the manuscript for publication produced a text in which two narrative voices are then discernible.
Cyclical functions and permutation matrices

Abstract Cyclical functions are an extension of the concept of hyperbolic functions. These functions have many interesting and important properties. This paper develops the theory of these functions from a novel point of view by using the properties of permutation matrices. The connection between cyclical functions and the matrix exponential function of the permutation matrix is demonstrated. The cyclical functions of the third and fourth orders are discussed in detail and the general theory of cyclical functions of order n is given. Applications of the fourth-order cyclical functions to the vibrations of beams are considered.
THE MASS MEDIA, POLITICAL ATTITUDES, AND BEHAVIOR:

The primary concern of this study is the effect f mass media on behavioral and attitudinal patterns of the general public. Specifically, the study focuses on the effects of media on political behavior and attitudes. Previous research indicates that it is difficult to distinguish these effects from other factors such as social class. In a 1966 study of the effects of the media on the political attitudes and behavior of southern blacks, Matthews and Prothro found that exposure to the media favorably affected political participation, interest, information, efficacy, and attitudes toward change. In 1975, Strouse reanalyzed their data—this time using multivariate techniques—and found that their conclusions were sound and not due to lack of proper statistical controls. The present study utilizes the perspectives of modernization theory and the more recently formulated uses and gratifications approach in an effort to go beyond Matthews and Prothro, and with a more recent sample. Using data gathered in 1974, samp...
Mass balance calculations with end member compositional variability: applications to petrologic problems

Although end member compositional variability is quite common, most quantitative mass balance procedures cannot accommodate this variability in a systematic manner. By rearranging the traditional mass balance relations, a series of equations can be derived to account for such heterogeneity. While this approach can be applied ton-component systems, the results are difficult to represent graphically. Accordingly, the procedure is most useful for two- and three-component systems. For two components, the concentration of an element in a mixture is: Cpm=ChmX+(1−1X)C1 and the isotopic signature is: epmC¯pm=ehmC¯hmX+(1−1X)e1C¯1 where pm, hm and 1 refer to parental magma, hybrid magma and component 1, respectively, X is the proportion of parental magma, C is concentration, ɛ is isotopic ratio, and C¯ the concentration of the denominator isotope in the particular isotopic ratio of interest. These equations describe straight lines, termed isoproportional or IP lines, of fixed mixing proportion in the Cpm−C1 concentration or epmC¯pm−e1C¯1 planes. Only those IP lines intersecting the rectangle defined by observed end member compositions represent viable mixing proportions. For three-component systems, the mass balance equations are: Y=(Chm−C2)−X(Cpm−C2)C1−C2 and: Y=(C¯hmehm−C¯2e2)−X(C¯pmepm−C¯2e2)C¯1e1−C¯2e2 where Y is now the proportion of component 1 and the proportion of component 2, Z, is simply 1 − X − Y. Using major, trace and rare earth element as well as isotopic data, a region of the X-Y plane representing possible mixing combinations can be defined. Due to the compositional variability of most magmatic end members, this new mass balance procedure should be applicable to a diverse range of petrologic problems. This procedure has been applied to three different petrologic processes: Aleutian parental magma genesis, assimilation/contamination, and crust-mantle differentiation.
Nanomechanical measurements of polyethylene glycol hydrogels using atomic force microscopy

Poly(ethylene glycol) (PEG)-based hydrogels are among the most widely used synthetic polymers for biomedical applications. Critical parameters of importance for PEG hydrogels are their mechanical properties which can be highly tuned. While properties such as elastic moduli have been measured at the bulk scale, it is often important to measure them at the micro and nanoscales. Further, non-destructive measurements of material properties can enable in situ and high-throughput monitoring for applications including modulating cellular interactions. In this research, the elastic modulus and the stiffness of polyethylene glycol diacrylate (PEG-DA) hydrogel matrices at the nanoscale are determined via nanoindentation using an atomic force microscope (AFM). The effect of varying parameters including monomer molecular weight, initiator concentration and rates of hydration on the mechanical strength of photopolymerized hydrogels were investigated. We present the effects of indentation parameters including loads and indent depths on such measurements. Mechanical characteristics of versatile PEG hydrogels can be adjusted based on polymer chain length and crosslinking, while completely hydrated hydrogels have mechanical properties similar to articular cartilage. A better understanding of these properties can enable tailoring hydrogel based biomaterials for various applications in scaffolds and tissue engineering.
Effects of growth medium, incubation temperature, and mycelium age on production of five major fatty acids by six species of Phytophthora

The effects of growth medium, incubation temperature, and mycelium age on the production of five major fatty acids by five isolates each of P. cactorum, P. citricola, P. citrophthora, P. cinnamomi, P. cryptogea, and P. nicotianae were investigated. Fatty acids were extracted from mycelia, and fatty acid methyl ester (FAME) profiles were analyzed by gas chromatography. Fifteen fatty acids were common in all species, but five of them comprised more than 75% of FAME profiles. These five fatty acids – myristic (14:0), palmitic (16:0), linoleic (18:2ω6c), oleic (18:1 ω9c), and eicosapentaenoic (20:5ω3c) acids – were used to investigate the effects of five liquid growth media (20% carrot broth, CB; 10% lima bean broth, LBB; 5% clarified V8 juice broth, V8B; ¼-strength potato dextrose broth, PDB; and ¼-strength Sabourand dextrose broth; SDB), six incubation temperatures (10, 15, 20, 25, 30, and 35°C), and four mycelium ages (4, 8, 12, and 16 days) on fatty acid production. The effect of medium on the relative pe...
Endothelin induces transcription of fos/jun family genes: a prominent role for calcium ion.

The 21-amino acid mammalian peptide endothelin (ET) is a powerful vasoconstrictor, a mitogen for fibroblasts and vascular smooth muscle cells, and a potent effector for numerous tissues. Through extracellular interaction with G protein-coupled transmembrane receptors, ET stimulates intracellular second messenger events that in turn activate immediate early gene transcription. Using Northern blot hybridization and nuclear run-on analyses, we examined the modulation of c-fos, fos-B, fra-1, c-jun, and jun-B gene transcripts in Rat-1 fibroblasts after ET treatment. Furthermore, we investigated the role that intracellular Ca2+ transients played in effecting this gene regulation, using the intracellular Ca2+ chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) to block Ca(2+)-dependent transcription. Our results demonstrate that ET rapidly effects increased RNA levels for all five fos/jun family genes investigated, at least two of them by increasing gene transcription. Furthermore, our resu...
An Introduction to Integrated Optics for Computing

Some of the fundamentals of integrated optics are discussed so that other articles may be better understood. This discussion includes both guided wave optics and free space optics. While the primary concern is not with free space optics, a cursory coverage of lenses is necessary because many of the fundamental operations are the same as in guided wave optics, and certain systems that have been proposed make use of both guided and free space optics.
A practical approach for evaluating population and individual bioequivalence.

Pharmacokinetic measurements provided by subjects to each of two formulations of a drug have a joint distribution that can be characterized by parameters reflecting scale and correlation as well as location. The bioavailability of the formulations can be expressed in terms of the means of the marginal distributions, their means and variances, or the marginal means and variances and the joint correlation. These expressions correspond, respectively, to 'average', 'population', and 'individual' bioequivalence when the joint distribution of the measurements is bivariate normal. Current proposals for assessing the degree of bioequivalence of two formulations are based on statistics that are composites of variance components and squares of expected mean differences from a mixed linear model. There are technical and practical issues associated with these proposals, particularly that they require more complicated designs than the familiar 2 x 2 cross-over. This paper describes an alternative approach that can be applied with standard 2 x 2 cross-over designs, and that provides evaluations of population and individual bioequivalence that should be adequate for all practical clinical purposes. The approach is based on easily computed correlation and regression coefficients whose statistical properties under normality are well known and for which non-parametric and robust alternatives exist when normality cannot be assumed. The approach yields conclusions consistent with those obtained by the current proposals when applied to data sets supplied by the FDA. In the cases where the conclusions do not match, the new approach appears to be more consistent with the data.
Defining forces that are associated with shoulder dystocia: the use of a mathematic dynamic computer model.

Objective: A computer model was modified to study the impact of maternal endogenous and clinician-applied exogenous delivery loads on the contact force between the anterior fetal shoulder and the maternal symphysis pubis. Study Design: Varying endogenous and exogenous loads were applied, and the contact force was determined. Experiments also examined the effect of pelvic orientation and the direction of load application on contact force behind the symphysis pubis. Results: Exogenous loading forces (50-100 N) resulted in anterior shoulder contact forces of 107 to 127 N, with delivery accomplished at 100 N of applied load. Higher contact forces (147-272 N) were noted for endogenously applied loads (100-400 N), with delivery occurring at 400 N of maternal force. Pelvic rotation from lithotomy to McRoberts' positioning resulted in reduced contact forces. Downward lateral flexion of the fetal head led to little difference in contact force but required 30% more exogenous load to achieve delivery. Conclusion: Compared with clinician-applied exogenous force, larger maternally derived endogenous forces are needed to clear the impacted anterior fetal shoulder. This is associated with >2 times more contact force by the obstructing symphysis pubis. McRoberts' positioning reduces shoulder-symphysis pubis contact force. Lateral flexion of the fetal head results in the larger forces that are needed for delivery but has little effect on contact force. Model refinements are needed to examine delivery forces and brachial plexus stretching more specifically. (Am J Obstet Gynecol 2003;188:1068-72.)
Multi-bit continuous-time delta-sigma modulator for audio application

The design considerations for low-power continuous time (CT) delta-sigma (ΔΣ) modulators is studied and circuit design details for a 13.5 bit modulator are given. The converter has been designed in a 0.5 um C5FN AMI CMOS technology and achieves a maximum signal-to-noise ratio (SNR) of 85 dB in a 48 kHz bandwidth and dissipates 5.4 mW from a 5 V supply when clocked at 6.144 MHz. It features a third-order active-RC loop filter, a 4-bit flash quantizer along with a Data Weighted averaging (DWA). The loop filter architecture and its coefficients have been targeted for the minimum power dissipation. The DWA also has been implemented by standard cell based synthesis to further optimize power. The figure of merit (FoM) of the CT-ΔΣ modulator is 3.71 pJ/bit. The fabricated chip of the modulator occupies an area of 4.5 mm2.
Review of 676 second primary tumors in patients with retinoblastoma: association between age at onset and tumor type.

OBJECTIVE To obtain a more accurate understanding of second primary tumors (SPTs) by analyzing a large number of SPTs from the published literature. METHODS A literature search was performed to identify published cases of SPTs in patients with retinoblastoma. Patient age, radiation field, tumor location, and tumor type were analyzed for statistical association. RESULTS The study included 676 SPTs in 602 patients. Median age at diagnosis of SPT was 13.0 years (range, 0.3-60.4 years) for all SPTs, 2.7 years for midline intracranial primitive neuroectodermal tumors, 13.0 years for sarcomas, 27.0 years for melanomas, and 29.0 years for carcinomas. The median age at which SPTs occurred inside the radiation field was younger than that for SPTs occurring outside the radiation field or in patients who did not undergo irradiation (P < .001). Sarcomas occurred more commonly inside the radiation field (P < .001). Melanomas, lipomas, leukemias, and lymphomas occurred more commonly outside the radiation field or in patients who did not undergo irradiation (P < .001). CONCLUSIONS Retinoblastoma patients pass through multiple windows of susceptibility to specific SPTs. This information will aid health care providers in monitoring this high-risk group, and it provides new insights for studying the underlying genetic predisposition to SPTs.
Responses of Kura Clover to Sheep Grazing and Clipping: I. Yield and Forage Quality

Few perennial legume shave dependable long-term productivity under grazing in the northern USA. Our objective waste to determine the effects of frequent clipping and sheep(Ovis spp.) grazing on forage yield and quality of kura clover (Trifolium ambiguum. Bieb.), a rhizomatous perennial legume. Clipping and grazing trials were initiated on a 5-yr-old stand of ‘Rhizo’ kura clover on a Waukegan silt loam and conducted for 3 yr. Total season yield (mean of 8.6 Mg ha −1) was unaffected by clipping frequency until the third year, when five and six cuttings per season produced 80 and 70% as much forage, respectively, as either three or four cuttings. In the second and third years of sheep grazing treatments, kura clover rotationally stocked with 14-d rest periods produced 28 and 16 less forage, respectively, than that under rotational stocking with 28-d rest periods. In contrast to total season forage yield, spring yield following 3 yr of clipping and grazing did not differ among treatments. As, crude protein (CP) and in vitro digestible dry matter (IVDDM) concentrations increased from 222 to 254 and from 854 to 880g kg ‘1 DM, respectively, and neutral-detergent fiber (NDF) concentration decreased from 326 to 295 g kg ‘1 DM. Forage was of high quality, because leaf concentration always exceeded 850 g kg ‘1 of forage dry matter. Established kura clover is tolerant of frequent and close defoliation and warrants pasture use because of its long-term productivity and high forage quality Contribution of the Minnesota Agric. Exp. Stn. Publ. No. 20,806
Adaptive Distributed Fair Scheduling for Multiple Channels in Wireless Sensor Networks

A novel adaptive and distributed fair scheduling (ADFS) scheme for wireless sensor networks (WSN) in the presence of multiple channels (MC-ADFS) is developed. The proposed MC-ADFS increases available network capacity and focuses on quality-of-service (QoS) issues. When nodes access a shared channel, the proposed MC-ADFS allocates the channel bandwidth proportionally to the packet's weight which indicates the priority of the packet's flow. The packets are dynamically assigned to channels based on the packet weight and current channel utilization. The dynamic assignment of channels is facilitated by use of receiver-based allocation and alternative routes. Moreover, MC-ADFS allows the dynamic allocation of network resources with little added overhead. Packet weights are initially assigned using user specified QoS criteria, and subsequently updated as a function of delay and queued packets. The back-off interval is also altered using the weight adaptation. The weight update and back-off interval selection ens...
White Matter Integrity is Associated with Treatment Outcome Measures in Cocaine Dependence

Cocaine dependence is associated with white matter impairments that may compromise cognitive function and hence drug users' abilities to engage in and benefit from treatment. The main aim of this study was to assess whether white matter integrity correlates with treatment outcome measures in cocaine dependence. Diffusion tensor imaging (DTI) was used to assess the white matter (WM) of 16 treatment-seeking cocaine-dependent patients before 8 weeks of therapy. The measures for treatment outcome were longest self-reported duration of continuous cocaine abstinence, percent of urine screens negative for cocaine, and duration (weeks) of treatment retention. Correlations between treatment outcome measures and DTI parameters (fractional anisotropy (FA), longitudinal eigenvalue (lambda(1)), perpendicular eigenvalue (lambda(T)), and mean diffusivity (MD)) were analyzed. Longest self-reported abstinence from cocaine and percent of cocaine-negative urine samples during treatment positively correlated with FA values and negatively correlated with lambda(1), lambda(T), and MD values across extensive brain regions including the corpus callosum, frontal, parietal, temporal, and occipital lobes, and cerebellum. The findings of an association between better WM integrity at treatment onset and longer abstinence suggest that strategies for improving WM integrity warrant consideration in developing new interventions for cocaine dependence.
Comparison of 15-year survival for men and women after initial medical or surgical treatment for coronary artery disease: A CASS registry study

Objectives. This study compared the rates of coronary artery bypass graft surgery and 15-year survival for men and women after initial medical or surgical management. Background. There has been concern that women with coronary artery disease are managed differently than men and that men and women have a different prognosis. The Coronary Artery Surgery Study (CASS) registry is a large data base of well characterized patients with long-term follow-up. Methods. Patients underwent cardiac catheterization at 1 of 15 hospitals during 1974 to 1979. Bypass surgery rates were based on 12,452 men and 2,366 women. Survival results were based on 6,018 men and 1,095 women with operable coronary artery disease and initial medical management and 6,922 men and 1,291 women initially managed surgically. Results. At 15 years, bypass surgery rates were 75% for men and 72% for women (p = 0.91). The rates remained similar after adjustment for clinical and angiographic variables. The 15-year survival rate was 50% for men and 49% for women with initial medical treatment (p = 0.53) and 52% for men and 48% for women (p = 0.004) with initial surgical treatment, a difference similar to that for operative mortality (men 2.5%, women 5.3%, p Conclusions. The rate of bypass surgery did not differ between men and women. There were few differences in the survival of men and women. In general, both men and women with initial surgical treatment survived longer, although benefits were clinically and statistically significant only in those at high risk. The benefit was similar in both men and women.
Distinct TDP-43 pathology in ALS patients with ataxin 2 intermediate-length polyQ expansions

Amyotrophic lateral sclerosis (ALS) is a progressive, adult-onset neurodegenerative disease characterized by degeneration of motor neurons, resulting in paralysis and death. A pathological hallmark of the degenerating motor neurons in most ALS patients is the presence of cytoplasmic inclusions containing the protein TDP-43. The morphology and type of TDP-43 pathological inclusions is variable and can range from large round Lewy body-like inclusions to filamentous skein-like inclusions. The clinical significance of this variable pathology is unclear. Intermediate-length polyglutamine (polyQ) expansions in ataxin 2 were recently identified as a genetic risk factor for ALS. Here we have analyzed TDP-43 pathology in a series of ALS cases with or without ataxin 2 intermediate-length polyQ expansions. The motor neurons of ALS cases harboring ataxin 2 polyQ expansions (n = 6) contained primarily skein-like or filamentous TDP-43 pathology and only rarely, if ever, contained large round inclusions, whereas the ALS cases without ataxin 2 polyQ expansions (n = 13) contained abundant large round and skein-like TDP-43 pathology. The paucity of large round TDP-43 inclusions in ALS cases with ataxin 2 polyQ expansions suggests a distinct pathological subtype of ALS and highlights the possibility for distinct pathogenic mechanisms.
Hydrogen production in a compact supercritical water reformer

Abstract Experiments were conducted to investigate the reforming of organic compounds (primarily methanol) in supercritical water at 550–700°C and 27.6 MPa in a tubular Inconel 625 reactor. The results show that methanol can be completely converted to a product stream that is low in methane and near the equilibrium composition of hydrogen, carbon monoxide, and carbon dioxide. The effect of reactor temperature, feed concentration of methanol, and residence time on both conversion and product gas composition was investigated and the results are presented. Reaction pathways and potential applications of this technology are discussed. Ethanol and ethylene glycol resulted in less desirable effluent gas, with high concentrations of methane and carbon monoxide. Acetone and diesel fuel both resulted in the reactor becoming plugged.
Perianesthesia care of the patient with gastroesophageal reflux disease

Every day millions of people suffer heartburn and other related symptoms of gastroesophageal reflux disease (GERD). Because symptoms can lead to a reduced quality of life, GERD sufferers are desperate for relief. This article explores the definition and pathophysiology, clinical manifestations, diagnostic procedures, and treatment options for GERD, including lifestyle modifications, medications, surgery, and alternative procedures. It also discusses preoperative, anesthesia/intraoperative, and postoperative special care considerations for the surgical patient with GERD.
Analysis and design of a push-pull current-fed converter

Four modes of operation are possible for the basic push-pull current-fed converter. Each mode is analyzed, circuit waveforms are explained, and relationships that influence the converter design are developed. Various design options and selection guidelines are presented along with experimental results.
Calcium-dependent release of exogenously loaded gamma-amino-[U-14C]butyrate from synaptosomes: time course of stimulation by potassium, veratridine, and the calcium ionophore, A23187.

—Synaptosomes which had taken up [14C]GABA were applied to a filter and rapidly perfused with various solutions in order to study the time course of release of this putative transmitter and the characteristics of its release. Depolarization of the synaptosomes with veratridine or 56mM-K+ or pretreatment with the Ca2+ ionophore, A23187, increased the calcium-dependent efflux of [14C]GABA. Release of [14C]GABA was increased by Ca2+ within 0.3 s of exposure, and the maximal release rate was not maintained for longer than 0.6 s. The reduction in the rate of release was not attributable to a decrease in calcium influx, but rather appeared to reflect fatigue at some subsequent stage in release. Stimulation by 56mM-K+ also elicited a calcium-independent increase in the efflux of radioactive GABA, which appeared to arise in part from subcellular particles other than synaptosomes.
Chemical self diffusion in CdTe

Abstract The diffusion constant determining the rate of the variation in the stoichiometric composition of CdTe for a change in cadmium pressure is measured for indium doped crystals. The results for doped as well as undoped crystals are expressed in terms of previously determined equiconcentration tracer diffusion constants using a detailed point defect model. Factors responsible for asymmetrical behavior are discussed.
Operator equations and nonlinear eigenparameter problems

Abstract Theorems concerning the existence and the approximation of roots of operator equations in an abstract space are established and then applied, advantageously, to extend the theory of nonlinear eigenparameter problems.
Effects of dietary DDT on blood plasma levels of calcium and magnesium in laboratory rats

The insecticidal action of DDT was discovered in 1939 but no one yet knows what its toxic mechanisms are. This paper reports on a study of the plasma levels of calcium and magnesium as af ~ fected by the presence of DDT in the diet of laboratory rats. DDT alters the observed electrical activity of the nerve. GORDON and WELSH (1948) reported repetitive firing and spontaneous activity from DDT-poisoned nerve in the crayfish. This effect could be inhibited by the addition of calcium or magnesium ions. It has been suggested (MATSUMARA, et al. 1969) that the nerve enzyme adenosine triphosphatase (ATPase) might actually be the site of DDT attack. Two kinds of ATPase are of concern and have been identified (PUSKIN, et al. 1968). Both kinds are dependent upon the presence of certain ionic species. One requires Na +, K +, and Mg ++ and is referred to as the Na-K-Mg type. The other requires Ca q-F or Mg ++. The Na-K-Mg type is assigned a governing role in cation transport across the cell membrane (GERMAIN and PROULX 1965, SKOW 1965). It has been suggested (GERMAIN and PROULX 1965) that the Ca-Mg type may be involved in the release of acetylcholine. In a study of human bood plasma, WALSER (1961) reported that calcium and magnesium ions occur in several forms. The predominant species are the free ion and the protein-bound ion. Several complexed forms occur, the mono-hydrogen phosphate and citrate complexes being the only two WALSER identified. Apparently no studies have been done on the effects of DDT on magnesium levels and the only calcium studies were on birds in which no change in total calcium is detected (PUJMAN, et al. 1970, BITMAN, et al. 1969, PEAKALL 1969 and 1970, SIMPSON, et al. 1972). The studies reported herein involved total and nonprotein-bound levels of calcium and magnesium as a function of dietary DDT. Feeding the insecticide was chosen as an approximation to an environmental possibility. EXPERIMENTAL Twenty-four of the rats used were hooded females (LONGEVANS) and two were albinos (SPRAGUE-DAWLEY). One of the albinos was male. The rats were ten to twelve months old and averaged 259 grams. The females were paired and housed in wire cages; the male was housed singly in a metal cage. AI1 animals were on free feed and water. The feed was a vitaminand mineral-supplemented grain mixture. The DDT was obtained from Montrose Chemical Corporation of
Mad2 and Mad3 Cooperate to Arrest Budding Yeast in Mitosis

Summary Background The spindle checkpoint ensures accurate chromosome transmission by delaying chromosome segregation until all chromosomes are correctly aligned on the mitotic spindle. The checkpoint is activated by kinetochores that are not attached to microtubules or are attached but not under tension and arrests cells at metaphase by inhibiting the anaphase-promoting complex (APC) and its coactivator Cdc20. Despite numerous studies, we still do not understand how the checkpoint proteins coordinate with each other to inhibit APC Cdc20 activity. Results To ask how the checkpoint components induce metaphase arrest, we constructed fusions of checkpoint proteins and expressed them in the budding yeast Saccharomyces cerevisiae to mimic possible protein interactions during checkpoint activation. We found that expression of a Mad2-Mad3 protein fusion or noncovalently linked Mad2 and Mad3, but not the overexpression of the two separate proteins, induces metaphase arrest that is independent of functional kinetochores or other checkpoint proteins. We further showed that artificially tethering Mad2 to Cdc20 also arrests cells in metaphase independently of other checkpoint components. Conclusion Our results suggest that Mad3 is required for the stable binding of Mad2 to Cdc20 in vivo, which is sufficient to inhibit APC activity and is the most downstream event in spindle checkpoint activation.