cssi/SciSciGPT-SciSciNet huggingface dataset:
The utilization of protoporphyrin 9 in heme synthesis.

Abstract The experiments described in this communication demonstrate that C14-tagged protoporphyrin 9 can be incorporated into the heme during the biosynthesis of hemoglobin. 1. In vitro observations: (a) C14 protoporphyrin 9 was found to be incorporated into heme by hemolysates of chicken and human blood incubated at 37 C. The degree of incorporation by washed chicken erythrocytes was less, presumably because the protoporphyrin was not readily transferred across the cell membrane. Incorporation by hemolysates was inhibited completely at 1 × 10-2 M KCN at 4 C., markedly by 1 × 10-2 M KCN at 37 C. and partially by 1 × 10-3 M Pb at 37 C. (b) The degree of incorporation was reduced by the addition of an equivalent quantity of delta-aminolevulinic acid. Furthermore, the incorporation of glycine-2-C14 into heme was reduced by the addition of an equivalent quantity of protoporphyrin 9. 2. In vivo observations: Intravenously administered C14 protoporphyrin was incorporated into the circulating hemoglobin of two rabbits with a phenylhydrazine-induced hemolytic anemia. These observations provide support for the view that protoporphyrin 9 itself is a true direct precursor of hemoglobin, in the biosynthetic pathway between porphobilinogen and heme. Comparative studies of rates of incorporation of C14 protoporphyrin 9 and its precursors into heme in vitro may provide a useful tool for the study of heme synthesis in normal and pathologic conditions. For instance, it was shown that hemolysates from the blood of patients with thalassemia major, with poor iron and glycine utilization, rapidly incorporated the tagged protoporphyrin into heme.
Ultimate Boundedness and Asymptotic Stability of Uncertain Dynamical Systems Via Variable Structure Control Approach

This paper is devoted to feedback control of a class of imperfectly known dynamical systems. State feedback structures are proposed which guarantee uniform ultimate boundedness (practical stability) of all motions of the closed-loop system. A transformation which decouples the "fast" and "slow" states is utilized in the analysis. A variable structure control approach and Lyapunov type arguments are employed to find the ultimate bounds for a subclass of closed-loop uncertain systems with matched and unmatched bounded uncertainties.
Wide area differential GPS as a future navigation system in the U.S

The Global Positioning System (GPS) is an extremely accurate positioning sensor with an accuracy of 100 meters. However in aircraft precision approaches, higher accuracy is required. Conventional differential GPS (DGPS) usually has accuracies of 1-3 meters within 100 kilometers of the reference station, even with selective availability (SA) errors. If DGPS is implemented on a large scale, the total number of monitor stations needed to cover the continental U.S. to the same accuracy would exceed 500. Wide area differential GPS (WADGPS) is a system that can reduce the number of monitor stations substantially while achieving the same accuracy. Test results showed a meter 3D positioning error with zero latency and 2-5 m 3D positioning error with 5-10 seconds of latency using WADGPS which has 6 monitor stations with 1632 km minimum baseline to a dual frequency user. >
Voltammetric approaches to kinetics and mechanism of the norepinephrine transporter.

Publisher Summary Rotating-disk electrode voltammetry (RDEV) has been used to determine kinetic arameters of dopamine (DA) and norepinephrine (NE) at the hNET in LLC-NET cells. As uptake occurs, the decreasing current is recorded for 6 min as a new steady-state is approached. To induce efflux, 6 μ l of unbuffered electrolyte as a control or 1, 10, or 100 μ M of selected substrate is added to the suspension, and the efflux of DA is monitored. At first, there is little l-amphetamine relative to the high concentration of DA on the inside of the cells to compete for outward transport. However, as it accumulates intracellularly, it competes with DA for binding to the empty transporter and DA efflux decreases. At the same time, DA concentration in the medium increases, causing an increase in the inward flux of DA. Amphetamine is known to inhibit the uptake of norepinephrine across the neuronal membrane and participate in the transmitter's release through the transporter. It was hypothesized that amphetamine-induced release was through an exchange diffusion mechanism. Because of the highly lipophilic nature of amphetamine, it is also capable of entering the cell by diffusion, complicating the analysis. The effect of using methylphenidate as an effluxing agent was also examined. Methylphenidate, as with d -amphetamine, has been used to treat attention deficit disorder with hyperactivity. Its mode of action is believed to be similar to that of cocaine in that it inhibits the DA transporter.
Perspective: Physician leadership in quality.

AbstractWhile advances in biomedicine are awesome, progress in patient safety and quality of care has proven slow and arduous. One factor contributing to the labored progress is the paucity of physician–leaders who can help advance the science and practice of quality and safety. This limited talent
Transport equations for the analysis of heavily doped semiconductor devices

Abstract Transport equations for use in analyzing heavily doped semiconductor devices are considered. These transport equations describe the effects of the nonuniform band structure and the influence of Fermi-Dirac statistics, which are important in heavily doped semiconductors. Previous workers [1, 2] have derived transport equations in terms of the nonuniform band structure. These equations, however, are not convenient for use in semiconductor device analysis because the band structure of heavily doped semiconductors is not well known. In this paper, the transport equations of Marshak and van Vliet [1, 3] are recast into a simple, Boltzmann-like form in which the effects associated with the nonuniform band structure and degenerate carrier concentrations are described by two parameters, the effective gap shrinkage, Δ G , and the effective asymmetry factor, γ. The experimental determination of both of these parameters is also discussed. Finally, Adler's contention [4], that some important features of semiconductor device operation can be modeled accurately by using an electrically measured Δ G with an arbitrarily chosen γ, is considered. The validity of this procedure, under certain simplifying assumptions, is established.
Therapy Insight: type 2 diabetes mellitus and the risk of late-onset Alzheimer's disease

A number of well-designed epidemiological studies have linked type 2 diabetes mellitus (T2DM) with an increased risk of Alzheimer's disease (AD). Several mechanisms could help to explain this proposed link, including insulin and insulin resistance, inflammatory cytokines, and oxidative stress. Obesity or physical inactivity might also influence AD through effects on hypertension, insulin sensitivity or inflammation. Typical AD pathology, such as amyloid-beta deposits, might be exacerbated by insulin dysregulation, T2DM itself, or microvascular disease that is a consequence of T2DM. T2DM patients are not routinely evaluated for cognitive outcomes, and cognitive impairment in T2DM is rarely treated. Similarly, AD patients are not routinely evaluated for T2DM or hyperinsulinemia. Current treatments for AD have only modest benefits, and several drugs that target metabolic and inflammatory pathways are being evaluated, most notably the statins, which reduce LDL and inflammation but might not influence amyloid- deposition, an important precursor for AD. Although some evidence supports a potentially important role for peroxisome proliferative activated receptor agonists such as glitazones, at present there are no published randomized clinical trials in AD patients of any drugs that target insulin or insulin resistance. Clinical implications of the T2DM-AD link include cognitive evaluations of patients with T2DM, and potential benefits for such patients through treatment with statins or diabetes drugs that target insulin.
The role of individual personality type in subjective risk elicitation outcomes

Managing uncertainty is an unavoidable challenge in a variety of decision contexts. On many occasions, objective data are not available, necessitating the use of experts. However, research into procedures to elicit and aggregate information from experts is difficult to validate or test empirically. A controlled economic experiment was used to assess subjective probability elicitation accuracy resulting from three alternative elicitation procedures and two aggregation alternatives. The empirical results provide evidence of the impacts of elicitation techniques, distribution type, and personal characteristics such as risk preferences and personality type on subjective risk assessment accuracy. Our conclusion is that experimental approaches hold promise as a technique to assess the forecast accuracy of aggregated subjective probabilities in a variety of contexts.
FIBER PRODUCTS AND CLASS GROUPS OF HYPERELLIPTIC CURVES

Let F q be a finite field of odd characteristic, and let N be an odd natural number. An explicit fiber product construction shows that if N divides the class number of some quadratic function field over F q , then it does so for infinitely many such function fields.
Differential Effect of Near-Threshold Stimulus Intensities on Sound Localization Performance in Azimuth and Elevation in Normal Human Subjects

The ability of humans to localize sounds remains relatively constant across a range of intensities well above detection threshold, and increasing the spectral content of the stimulus results in an improvement in localization ability. For broadband stimuli, intensities near detection threshold result in fewer and weaker binaural cues used in azimuth localization because the stimulus energy at the high- and low-frequency ends of the audible spectrum fall below detection threshold. Thus, the ability to localize broadband sounds in azimuth is predicted to be degraded at audible but near threshold stimulus intensities. The spectral cues for elevation localization (spectral peaks and notches generated by the head-related transfer function) span a narrower frequency range than those for azimuth. As the stimulus intensity decreases, the ability to detect the stimulus frequencies corresponding to the spectral notches will be more strongly affected than the ability to detect frequencies outside the range where these spectral cues are useful. Consequently, decreasing the stimulus intensity should degrade localization in both azimuth and elevation and create a greater deficit in elevation localization due to the narrower band of audible frequencies containing elevation cues compared to azimuth cues. The present study measured the ability of 11 normal human subjects to localize broadband noise stimuli along the midsagittal plane and horizontal meridian at stimulus intensities of 14, 22, and 30 dB above the subject's detection threshold using a go/no-go behavioral paradigm. Localization ability decreased in both azimuth and elevation with decreasing stimulus intensity, and this effect was greater on localization in elevation than on localization in azimuth. The differential effects of stimulus intensity on sound localization in azimuth and elevation found in the present study may provide a valuable tool in investigating the neural correlates of sound location perception.
Program evaluation of an intervention approach for staff assaulted by patients: Preliminary inquiry

Crisis intervention procedures for emergency services personnel and healthcare providers are increasingly being utilized to address the psychological sequelae of acute stress during critical incidents. While anecdotal evidence suggests the efficacy of these approaches, more formal experimental inquiry has been limited. This brief report outlines one strategy for conducting program evaluation of a crisis intervention approach for staff who are assaulted by patients. This outcome design was implemented in multiple sites, even as the service was being delivered.
Response of “acute phase” globulins in different models of inflammation in rats

Abstract The levels of “acute phase” globulins of inflammation (APG) were examined in rats following intraplantar injections of different irritants, cotton granuloma formation and adjuvant arthritis. The levels of APG were found to be highly related to inflammatory events associated with acute necrosis, whereas the relationship of APG to edematous or fibroplastic inflammatory events was minimal. In adjuvant arthritis, the APG levels were related to the severity of the gross symptoms of the disease: arthritis scores, feet weights, splenomegaly and swelling at the adjuvant injection site in tail. Inflammation associated with acute necrosis at any one of these sites could have triggered the production of APG. Administration of anti-inflammatory drugs could disassociate the direct relationships between APG levels and the severity of the different gross symptoms of adjuvant arthritis.
Graph-Theoretic Methods for Measurement-Based Input Localization in Large Networked Dynamic Systems

In this paper, we consider the problem of localizing disturbance inputs in first-order linear time-invariant (LTI) consensus networks using measurement-based graph-theoretic methods. We consider every node and edge of the network graph to be characterized with physical weights, and show that the resulting system dynamics can be represented in terms of an asymmetric Laplacian matrix $L_{m}$ . Assuming the network graph to be divided into $p$ coherent clusters, we next propose an input localization algorithm based on the properties of the weak nodal domains corresponding to the first $p-1$ slow eigenvalues of $L_{m}$ . The algorithm takes in sensor measurements of the states from selected nodes, runs a system identification routine to construct the input-output transfer matrix, and compares the signs of the residues of the component transfer functions to a nominal localization key to determine in which cluster(s)the disturbance input may have entered. We prove that for systems defined over a specific class of graphs, referred to as $p$ -area complete graphs, the localization is unique. We also state the extension of this result for second-order synchronization networks. We illustrate the algorithms by applying them to large-scale power system networks.
Mass transport kinetics of the DNA-binding dye Hoechst-33342 into bovine spermatozoa.

Abstract The mass transport kinetics for the unmediated diffusion of Hoechst-33342 dye (HO-33342) into spermatozoa was established at varying pH and temperature. The mass transport diffusion coefficient kdiff at 41.5 °C and pH 6.2 was determined to be 0.0435 min−1 [M sperm/mL]−1 and the energy of activation Ea associated with the temperature dependency of kdiff at 14.2 kcal/gmoL. The relationship of kdiff to pH was based mechanistically on the premise that the HO-33342 dye becomes more hydrophobic as the pH becomes more alkaline and therefore facilitates transport. The kdiff dependency on pH was described mathematically using a form of the Henderson–Hasselbalch equation in which the pKa of the HO-33342 dye was 6.6. Using the kinetic parameters, an Excel-based model was developed capable of predicting the time required for the HO-33342 dye to reach any specified level of saturation in the spermatozoa.
Fresnel Drag Measurements for Determination of Ultra-Slow Flow Rates

n this paper, we show theoretically that by using a diffraction limited interaction pipe together with a state-of-the-art Sagnac interferometer, the minimum detectable flow rate may be decreased to less than one drop per day. Experimentally, we demonstrate a minimum detectable flow rate of one drop per five hours. This new experimental result represents a 300 fold improvement in the sensitivity to slow flows over our previous best result.
Adenotonsillar Histopathology After Organ Transplantation

Abstract Objectives: The increasing number of surviving pediatric organ transplant recipients has resulted in a new clinical controversy surrounding the significance of adenotonsillar hypertrophy. The objective of this study is to evaluate adenotonsillar specimens, understand characteristic histopathology, and to examine the frequency and significance of this finding in this population. Methods: Twenty-one cases of pediatric transplant recipients with adenoidal and/or tonsillar hypertrophy were reviewed retrospectively in a tertiary-care setting. Particular attention was given to the histopathology of their surgical specimens, including any evidence of posttransplantation lymphoproliferative disorders (PTLD). Results: Using morphologic, immunohistochemical, and molecular genetic analyses, 15 (71%) of 21 patients were noted to have Epstein-Barr virus (EBV)-related lymphoid hyperplasia, including 1 case (4.7%) of PTLD. Six (29%) of 21 had evidence of reactive follicular hyperplasia not related to EBV. B-cell and T-cell markers were nearly uniformly positive when tested for, except in the single patient with PTLD, who exhibited polymorphic, polyclonal B-cell morphology. Kappa and lambda light-chain clonality markers were positive in 11 (92%) of 12 patients. Conclusions: EBV-related lymphoid hyperplasia is frequently associated with adenotonsillar hypertrophy in pediatric organ transplant patients (71% of our cases); 92% of those cases tested exhibit polyclonal B-cell populations. PTLD, an important cause of morbidity and mortality in this population, represented approximately 5% of our cases. The remainder of cases represent follicular hyperplasia unrelated to EBV or lymphoproliferative abnormalities. Characteristic histopathologic findings are presented. (Otolaryngol Head Neck Surg 2001;125:231-40.)
Geology and geochemical analysis of mineralizing fluids at the St. Cloud and U.S. Treasury Mines, Chloride Mining District, New Mexico

Abstract The St. Cloud-U.S. Treasury vein system is part of widespread, late Oligocene, epithermal mineralization that occurs along the eastern front of the Black Range, southwestern New Mexico, and occupies a normal fault related to the initial development of the Rio Grande rift. Stage 1 mineralization consists of galena, sphalerite, and chalcopyrite; and Stage 2 mineralization is bornite, sphalerite, chalcocite, digenite, betektinite, and complex copper-silver sulfides. Timing of mineralization is closely tied to an episode of regional volcanism that commenced at approximately 30 Ma and lasted until about 28 Ma. This episode consisted of two pulses of volcanism, initially with mafic to intermediate volcanism that was closely followed by rhyolite volcanism. Age dates and paleodepth considerations indicate that the two stages of mineralization are related to these two volcanic pulses, respectively. Fluid inclusion homogenization temperatures and salinities for both stages of mineralization overlap and range from 210 to 294°C, and from 0.0 to 3.4 eq.wt.% NaCl. Stage 1 inclusions have slightly higher Th and salinity values than Stage 2. Within these ranges of temperature and salinity for both stages of mineralization, three populations were identified by cluster analysis and cumulative frequency plots: high temperature, high salinity (A); high temperature, low salinity (B); and low temperature, low salinity (C). Gaseous species found in inclusion fluids analyzed by quadrupole mass spectrometry are CO2, CnHn, H2S, N2, CH4, SO2, and minor amounts of H2, CO, He, and Ar. Gas chromatography/mass spectrometry measurements indicate that CnHn is principally propene, butene, and pentene. Stage 2 inclusion fluids contain relatively greater amounts of H2S, CO2 and total gases Stage 1 inclusion fluids. Within each stage, the concentrations of all gases except H2S increase with elevation, whereas H2S shows an inverse relationship with elevation. Inclusion fluids from non-mineralized vein material have low concentrations of all gases. Concentrations of N2, CO2 and CH4 in inclusions are greatest in surface samples overlying and immediately adjacent to mineralized areas. Inclusion populations B and C for both stages of mineralization have low total-gas contents and are correlated with non-mineralized vein material; population A for both stages of mineralization have relatively higher concentrations of all gases, particularly H2S and CO2, and is correlated to sulfide mineralization. Analyses of channel samples from surface outcrops of the St. Cloud-U.S. Treasury vein indicate that a positive anomaly in CO2, N2 and N2/CO2 exists over mineralized shoots. These analyses could have located the blind ore bodies that were found at the St. Cloud mine.
Robert A. Mundell: A Profile

This essay is a short introduction to the work of Robert A. Mundell, winner of the Nobel Prize for Economics in 1999. It is a contribution to a special issue of Review of International Economics.
Virtual communities: the impact of a commercial orientation on the attitudes towards virtual communities

Adopting the view that a virtual community is an influential social entity, this study provides a theoretical framework that identifies a linkage among the individual values of virtual community members, commercial orientation of virtual communities and attitudes towards the information provided by virtual communities. The present study suggests that individual values (i.e., purposive, self-discovery, social and entertainment) influence the selection of virtual communities. The community's commercial orientation (i.e., commercial or noncommercial), in turn, influences the individual attitudes towards the information provided by the communities. Credibility, relevance and empathy are the proposed attitudes that individuals may form towards the information provided in virtual communities. The proposed model provides valuable implications for marketers and business people who want to source virtual communities as viable marketing channels.
Femtosecond Relaxation Processes In Semiconductors

Pump-probe spectroscopy is a common method in the study of ultrafast relaxation processes. In the study of the relaxation of hot electrons in semiconductors, there are two possible approaches using this method, each of whici yields different data about the relaxation processes. The first approach probes the relaxation of a population of hot electrons, which has previously been created by photoexcitation, by measuring the saturated absorption of a probe pulse which has a longer or shorter wavelength than the exciting pulse. As the wavelength of the probe is tuned, a picture of how the electrons move down the central valley is obtained.1,2 Some of the electrons, however, may not remain in the central valley as they lose energy but could be scattered to the satellite valleys, at least for short times. Since carriers in the satellite valleys are not connected by a direct optical transition to the valence band at typical photon energies, even an experiment which uses a tunable probe wavelength will not be able to probe all the possible states into which the electrons may scatter. The second approach is complementary to the first. Rather than probe the passage of electrons through states of lower energy than the initial state, the way in which they leave the initial states is determined by measuring the saturated absorption of a probe pulse of the same wavelength as the exciting pulse. A complete picture of the electron relaxation requires the results of both approaches. We have chosen to pursue the second scheme. A point that is often overlooked is that rough numbers for the scattering rates involved already exist, and if time-resolved spectroscopy is to add anything new it must be quantitative. This means, of course, that the data must have a high signal-to-noise ratio. One advantage of the second approach is that the high repetition rate of the pump laser may be put to good use in reducing noise in the data. Because the pump and probe pulses have the same wavelength, they may be generated directly from the output of the laser, and consequently the repetition rate of the experiment is equal to that of the repetition rate of the laser pulses, or about 100MHz. This leads to an increased signal-to-noise ratio as compared with the tunable pump-probe method, in which the pump and probe repetition rates are generally about 10 kHz.
Experimental Investigation of Unstably Stratified Buoyant Wakes

A water channel has been used as a statistically steady experiment to investigate the development of a buoyant plane wake. Parallel streams of hot and cold water are initially separated by a splitter plate and are oriented to create an unstable stratification. At the end of the splitter plate, the two streams are allowed to mix and a buoyancy-driven mixing layer develops. The continuous, unstable stratification inside the developing mixing layer provides the necessary environment to study the buoyant wake. Downstream a cylinder was placed at the center of the mixing layer. As a result the dynamic flows of the plane wake and buoyancy-driven mixing layer interact. Particle image velocimetry and a high-resolution thermocouple system have been used to measure the response of the plane wake to buoyancy driven turbulence. Velocity and density measurements are used as a basis from which we describe the transition, and return to equilibrium, of the buoyancy-driven mixing layer
System of Systems Architecture: The Case of Space Situational Awareness

The presence of space situational awareness is one approach to mitigating the long-term risks associated with space debris in low Earth orbit (LEO). As the U.S. and other nations continue to develop the space situational awareness mission area, questions arise as to how stakeholders should act to mitigate the effects of resident space objects and how our understanding of the physics of LEO inform the evolution of groundand space-based sensors. To characterize interactions among international stakeholders, space situational awareness is modeled as a system of systems with technical and social elements. Through the use of game-theoretic cooperation archetypes and System Dynamics modeling, possible futures are explored. Extensions in space situational awareness capabilities are modeled as mechanisms to improve satellite survivability. Finally, general implications for system architecture and systems of systems are elucidated.
Maximum Leadership: The World's Leading CEOs Share their Five Strategies for Success

The article reviews the book “Maximum Leadership: The World's Leading CEOs Share Their Five Strategies for Success,” by Charles M. Farkas and Philippe De Backer.
Pharmacotherapy of catamenial epilepsy

Epilepsy affects 50 million people worldwide. Women may be afflicted with catamenial epilepsy, a form of epilepsy related to the menstrual cycle. In catamenial epilepsy, seizures are clustered around the monthly cycle. Despite the availability of several standard and newer antiepileptic drugs, there is no specific and effective therapy for catamenial epilepsy. Moreover, the exact pathophysiology of catamenial seizures remains unclear. It is well known that progesterone possess anticonvulsive properties. The level of this hormone drops near the end of the cycle, leaving women more vulnerable to catamenial epilepsy. Recent studies have shown how progesterone protects women against seizures. Progesterone plays two roles in the brain. First, it binds to progesterone receptors in the brain, which help regulate the reproductive functions. Second, progesterone gets metabolized to allopregnanol-one in the brain called a neurosteroid. We found that allopregnanolone plays a crucial role in seizure protection. The withdrawal from this neurosteroid, which occurs during the menstrual cycle, could provoke seizures. Consequently, we suggest that neurosteroid replacement could be a novel therapeutic approach for catamenial epilepsy.
Serotonin-induced paw edema in the rat: Pharmacological profile

Abstract 1. 1. Serotonin (5-HT) induced a linear increase in paw weight in rats within 1hr of an intraplantar injection (50μ1 vol) over a concentration range of 0.005–0.2mg/ml. At the 0.2 mg/ml concentration, a 16-fold increase in paw weight was observed as compared to saline-injected controls. 2. 2. Serotonin antagonists, such as LY53857, were the most effective antagonists of 5-HT induced paw swelling, producing near complete antagonism and an approximate ED50 of 0.1 mg/kg. A mixed 5-HT/histamine antagonist, cyproheptadine, also produced a nearly complete inhibition of the 5-HT response with an approximate ED50 of 1.3 mg/kg. 3. 3. Dopamine agonists (pergolide, quinpirole), yohimbine, dexamethasone and nifedipine also produced a significant degree of antagonism of the 5-HT response. 4. 4. Clonidine, prazocin, chlorpheniramine, cimetidine, various dopamine antagonists, imipramine, cyclosporine A, piroxicam and superoxide dismutase were all ineffective at altering the paw swelling response to 5-HT.
Follow-up study on low- and high-risk hispanic high school students

Hispanic high school students at low or high risk for drop out were followed up 1 year after their expected graduation date. Low-risk students completed school at a significantly higher rate than high-risk students. In addition, analysis of original predictor variables indicated graduated students' greater satisfaction with school compared with nongraduates. Implications for promoting high-risk students' successful high school completion are discussed.
Mutagenesis of hetR reveals amino acids necessary for HetR function in the heterocystous cyanobacterium Anabaena sp. strain PCC 7120

HetR is the master regulator of heterocyst differentiation in the filamentous cyanobacterium Anabaena sp. strain PCC 7120. Genetic selection was used to identify 33 amino acid substitutions in HetR that reduced the proportion of cells undergoing heterocyst differentiation to less than 2%. Conservative substitutions in the wild-type HetR protein revealed three mutations that dramatically reduced the amount of heterocyst differentiation when the mutant allele was present in place of the wild-type allele on a replicating plasmid in a mutant lacking hetR on the chromosome. An H69Y substitution resulted in heterocyst formation among less than 0.1% of cells, and D17E and G36A substitutions resulted in a Het − phenotype, compared to heterocyst formation among approximately 25% of cells with the wild-type hetR under the same conditions. The D17E substitution prevented DNA binding activity exhibited by wild-type HetR in mobility shift assays, whereas G36A and H69Y substitutions had no affect on DNA binding. D17E, G36A, and H69Y substitutions also resulted in higher levels of the corresponding HetR protein than of the wild-type protein when each was expressed from an inducible promoter in a hetR deletion strain, suggesting an effect on HetR protein turnover. Surprisingly, C48A and S152A substitutions, which were previously reported to result in a Het − phenotype, were found to have no effect on heterocyst differentiation or patterning when the corresponding mutations were introduced into an otherwise wild-type genetic background in Anabaena sp. strain PCC 7120. The clustering of mutations that satisfied the positive selection near the amino terminus suggests an important role for this part of the protein in HetR function.
Application of an Artificial Neural Network in Radiographic Diagnosis

The description of 44 cases of bone tumors was used by an artificial neural network to rank the likelihood of 55 possible pathologic diagnoses. The performance of the artificial neural network was compared with the performance of experienced (3 or more years of radiology training) residents and inexperienced (less than 1 year of radiology training) residents. The artificial neural network was trained using descriptions of 110 radiographs of bone tumors with known diagnoses. The descriptions of a separate set of 44 cases were used to test the neural network. The neural network ranked 55 possible pathologic diagnoses on a scale from 1 to 55. Experienced and inexperienced residents also ranked the possible diagnoses in the same 44 cases. Inexperienced residents had a significantly lower mean proportion of diagnoses ranked first or second than did the neural network. Experienced residents had a significantly higher proportion of correct diagnoses ranked first than did the network. Otherwise, a significant difference between the performance of the network and experienced or inexperienced residents was not identified. These results demonstrate that artificial neural networks can be trained to classify bone tumors. Whether neural network performance in classification of bone tumors can be made accurate enough to assist radiologists in clinical practice remains an open question. These preliminary results indicate that further investigation of this technology for interpretation assistance is warranted.
A large Pi-1-2 set absolute for set forcing

Let k be a definable L-cardinal. Then there is a set of reals X, class-generic over L, such that L(X) and L have the same cardinals, X has size k in L(X) and some pi-1-2 formula defines X in all set-generic extensions of L(X). Two corollaries, both assuming the consistency of an inaccessible: It is consistent for the Perfect Set Property to hold for boldface sigma-1-2 sets, yet fail for some lightface pi-1-2 set. It is consistent that the Perfect Set Property holds for boldface sigma-1-2 sets yet some lightface pi-1-2 wellordering of some set of reals has length aleph-1000.
Role of the GABAA system in behavioral, motoric, and cerebellar protection by estrogen during ethanol withdrawal.

Abstract Results of studies from our laboratory have shown that administration of 17β-estradiol (E 2 ) reduces cerebellar neuronal damage during ethanol withdrawal (EW). In the current study, we investigated whether the GABAergic system is involved in the protective effects of E 2 against the EW syndrome. To test this hypothesis, we examined the effects of GABAergic drugs, with and without E 2 , on EW sign scores, motoric capacity, and caspase activation. Ovariectomized rats implanted with an E 2 or an oil pellet received liquid ethanol [7.5% weight/volume (wt./vol.)] for 5 weeks or dextrin diet, followed by 2 weeks of EW. A gamma-aminobutyric acid type A (GABA A ) agonist, muscimol (0.125 or 0.25 mg/kg), and antagonist, bicuculline (1.25 mg/kg), were administered (intraperitoneally; three times a day for 4 days) starting 1 day before the onset of EW. On termination of chronic administration of ethanol diet, rats were tested for overt withdrawal signs and latency to fall from a rotarod. The initial latency was measured separately to assess motoric capacity before learning occurred. Cerebelli were subsequently collected for immunohistochemistry to detect caspase activation. Results showed that treatment with E 2 lowered EW sign scores and improved initial as well as subsequent rotarod latencies compared with findings without treatment with E 2 (control group). These effects of E 2 were enhanced by combined treatment with muscimol and diminished by bicuculline. Results also showed that ethanol-withdrawn rats had more caspase-3–positive cells than observed for the dextrin diet–fed group in a manner reversed by E 2 and exacerbated by bicuculline. Bicuculline also caused partial antagonism of the protective effect of E 2 . These findings support the suggestion that GABA A agonists ameliorate, and GABA A antagonists exacerbate, EW signs, cerebellar neuronal damage, and motoric impairment in ethanol-withdrawn rats. Also, results of the current study provide indirect evidence that the GABAergic system is involved in protective effects of E 2 against the EW syndrome.
Recognizing Unrecognized Risk The Evolving Role of Ventricular Functional Assessment in Population-Based Studies

The rapid evolution of advanced cardiac imaging technologies has resulted in enhanced detection of subclinical disease with the potential for early implementation of therapeutic strategies and reduction in subsequent morbidity and mortality. Noninvasive assessment of ventricular function can provide evidence of prevalent coronary artery disease and cardiomyopathy and could supplant electrocardiography (ECG), the traditional marker of unrecognized myocardial infarction (UMI), in population screening. An appreciation of past efforts in this field is useful in understanding the potential future trajectories of these technologies. Article p 143 Ever since Herrick’s initial description of classic angina in 1912, it has been known that incident myocardial infarction (MI) will go unrecognized in a substantial portion of the population. Patients with UMI either recall symptoms that are atypical of MI or have no recollection of any event at all. Initially, autopsy findings and, later, ECG evidence indicated that “silent” MIs were frequent in hospitalized populations. These observations were later extended to a free-living cohort with the first epidemiological data reported from the Framingham Heart Study in 1959 by Stokes and Dawber.1 These investigators noted that 21% of subjects with new ECG-documented MI on biennial serial examinations had either atypical symptoms that were not clearly related to MI or no apparent ischemia-related complaints. Kannel and Abbott2 later observed that new Q-wave infarctions detected on biennial Framingham examinations over a 30-year follow-up period were unknown to 28% of the men and 35% of the women who experienced them, with approximately half of these MIs unaccompanied by discernible symptoms on further investigation. More impressive still was the fact that after MI diagnosis, the 10-year death rate was at least as great in subjects with UMI as in those with recognized infarction (45% versus 39%). As shown in the Table, these results have been confirmed by …
Building Cartesian trees from free trees with k leaves

Abstract One can build a Cartesian tree from an n-element sequence in O ( n ) time, and from an n-node free tree in O ( n log n ) time (with a matching worst-case lower bound in the comparison model of computation). We connect these results together by describing a Cartesian tree construction algorithm based on a “bitonicity transform” running in O ( n log k ) time on a free tree with k leaves, noting that a path is the special case of a tree with just 2 leaves. We also provide a matching worst-case lower bound in the comparison model.
Measurement of Transients

The transient crest meter was developed to investigate several pressing problems in high-voltage transients. It consists of a gold leaf electroscope in series with a rectifying device, an electron tube, which enables the electroscope to charge, but prohibits discharge. The charge that is captured in this manner is proportional to the maximum impressed potential, and where adequate insulation is possible, will remain substantially undiminished for many seconds or even minutes after the transient has passed by. The instrument described is thus seen to be essentially a crest voltmeter. By the proper use of inductance, resistance, and capacitance it is possible to make the applied voltage dependent upon the maximum peak, maximum slope, or maximum area of current and voltage waves, thus giving information regarding the character as well as the size of the transient. The method of calibration, and the precautions that must be taken in measuring transients with this instrument are pointed out in detail in the paper. In particular, care must be taken to carefully insulate the gold leaf. The minute charge stored at several hundred volts makes it necessary to employ special vacuum bulbs with the filament and plate leads coming through opposite ends of the tube. The crest meter has already served successfully in several investigations. The first application was the measurement of the potential of the sphere electrode of a high-voltage oscillator. The method followed consisted in measuring the charging current to the sphere by means of a shielded electroscope resting within this electrode. When combined with a second gold leaf acting as relay contact to give an alarm at a given voltage, the instrument is admirably suited for the study of transmission system disturbances, for the observer need be tied no closer to the test than remain within hearing distance of an electric bell. Such an application was made during four months of the past summer on a 110 kv. line belonging to the Pacific Gas & Electric Company, in an effort to discover the cause of apparently unprovoked flashovers which this particular line experiened from time to time. Other similar applications become evident as their need arises.
Polarization Cross-coupling Between Microring and Bus Waveguide in Double-layer SOI

We investigate polarization cross coupling between modes of microring resonators and waveguides due to structural asymmetries. We experimentally demonstrate the coupling between a double layer SOI waveguide fundamental TM mode and microring higher order radial TE modes.
Race differences in middle class lifestyle: The role of home ownership

Abstract This paper examines race differences in two aspects of “middle class” lifestyle: home ownership and net worth. Home ownership indicates stability; and for older persons net worth is an important part of economic status. Data from the NLS studies of older men are analyzed. The major findings are: (1) while whites at any earnings level are very likely to own homes by ages 50–64, only at relatively high earning levels do blacks begin to approach the home ownership rates of whites; (b) the net worth of blacks is substantially lower than that of whites after adjusting for variables in a standard status attainment model; and (c) however, among home owners the race difference as well as effects of other variables are much smaller than for renters. This is attributed to forced saving through home ownership. The paper concludes with a discussion of possible sources of low home ownership rates and low net worth of blacks and the implication of these findings for the study of middle class status.
A new perturbation approach to coupling between adiabatic states

Abstract A new perturbation expansion, formally related to Tanaka-Fukuda perturbation theory, is derived and applied to the general problem of nonadiabatic coupling. The coupling between adiabatic Born-Oppenheimer states in poly-atomic molecules is treated in detail in both the one- and multi-phonon limits, for which previous methods are often unreliable, even for order-of-magnitude estimates.
Star Couplers Fabricated In Ion-Exchanged Glass Substrates

A simple technique for fabricating single mode star couplers using ion-exchanged glass guides is proposed and demonstrated. Calculations indicate the possibility of achieving an excess loss of 2dB and a uniformity of 3dB for a lx32 star coupler. Furthermore the technique can be scaled to increase the number of ports without changing uniformity or excess loss.
Surface roughness of two dental amalgams after various polishing techniques

1. In comparison with standard polishing after 24 hours, no advantage is gained by using an abrasive paste after 10 minutes. Polishing after 24 hours produced a significantly smoother surface for both amalgam alloys on both the simulated proximal and occlusal surfaces. 2. The standard polishing procedures after 24 hours produced a smoother surface than any of the immediate finishing procedures tested. 3. The high-copper amalgam was signijficantly rougher with initial carving and immediate finishing, but surfaces of both alloys were equally smooth when polished after 24 hours. 4. Both amalgam alloys, when condensed against a new matrix band lacked smoothness when compared to the surfaces obtained by finishing after 24 hours. 5. There was a high correlation between arithmetic average roughness and average maximum peak height as quantitative measurements of surface texture.
Effect of ammonium chloride supplementation on urine pH and urinary fractional excretion of electrolytes in goats

Objective—To determine whether dietary supplementation with ammonium chloride would affect urine pH or urinary fractional excretion (FE) of electrolytes in goats fed grass hay. Design—Clinical trial. Animals—15 yearling castrated male goats. Procedures—In the dose response study, 3 yearling goats fed orchard grass hay and water ad libitum were administered ammonium chloride at either 200, 400, or 500 mg/kg (91, 182, or 227 mg/lb), PO, every 24 hours. In the FE study, 8 goats fed orchard grass hay were randomly divided into either a treatment (n = 4) or a control group (4). In the treatment group, ammonium chloride was administered at 450 mg/kg (2.25% of dry matter intake [DMI]), PO, every 24 hours for 8 days. The FE of electrolytes was compared between groups; FE measurements were also determined for 4 client-owned goats fed alfalfa hay. Results—Ammonium chloride administered at 450 mg/kg (2.25% of DMI) achieved and maintained urine pH < 6.5 for 24 hours. Goats fed orchard grass hay with ammonium chloride...
Fluorescence spectroscopy of normal and atheromatous human aorta: optimum illumination wavelength

The purpose of this investigation was to determine which illumination wavelength produces the largest differences between the fluorescence emission spectra of normal and atheromatous vascular tissue. The fluorescence spectra for 12 excitation wavelengths ranging between 270 nm and 470 nm were examined and compared. The Hotelling trace, a figure of merit describing class separability, was used to compare the excitation wavelengths. Preliminary results indicate that illumination in the range from 314 nm to 334 nm consistently performed well. Wavelengths in the 364 nm to 436 nm range also showed promising performance for a limited data set. These results were found to be relatively independent of the catheter angel and distance to the tissue.
Self-directed attention and the comparison of self with standards

Abstract Several theorists have assumed that self-directed attention causes a comparison between one's present behavior or state and whatever is salient and relevant as a standard of comparison. Indirect evidence bearing on this assumption was gathered in a series of four studies by monitoring subjects' tendencies to access concrete information needed to make such behavior-standard comparisons. Self-focus was varied in two of these studies by experimental manipulations: a mirrored surface, and a live observer. In the other two studies, self-focus was operationalized in terms of subjects' dispositional tendencies to direct attention to themselves (self-consciousness). Consistent with expectations, in Experiments 1 and 2, self-directed attention led to increased frequency of referring to drawings of geometric figures when attempting to reproduce them. In Experiments 3 and 4, self-focused attention increased subjects' tendencies to seek out information about ostensible performance norms reflecting the behavior of other subjects, also as predicted.
An atomistic perspective on twinning phenomena in nano-enhanced fcc metals

Twin boundaries exist in bulk metals, and they are even more common in metallic nanomaterials. Molecular simulation has made it possible to achieve a predictive understanding of the atomic mechanisms leading to the enhanced properties of nano-twinned metals. Taking nanowires as prototypes, this paper presents an atomistic view of twin structure and its important role in synthesis and in mechanical deformation.