cssi/SciSciGPT-SciSciNet huggingface dataset:
Conversion of 1-alkyl-2-acetyl-sn-glycerols to platelet activating factor and related phospholipids by rabbit platelets

Abstract The metabolic pathway for 1-alkyl-2-acetyl- sn - glycerols , a recently discovered biologically active neutral lipid class, was elucidated in experiments conducted with rabbit platelets. The total lipid extract obtained from platelets incubated with 1-[1,2- 3 H]alkyl-2-acetyl- sn - glycerols or 1-alkyl-2-[ 3 H]acetyl - sn - glycerols contained at least six metabolic products. The six metabolites, identified on the basis of chemical and enzymatic reactions combined with thin-layer or high-performance liquid chromatographic analyses, corresponded to 1-alkyl- sn - glycerols , 1-alkyl-2-acetyl- sn - glycero-3-phosphates , 1-alkyl-2-acyl(long-chain) - sn - glycero-3-phosphoethanolamines, 1-alkyl-2-acetyl - sn - glycero-3-phosphoethanolamines, 1-alkyl-2-acyl(long-chain)- sn -glycero-3-phosphocholines, and 1-alkyl-2-acetyl- sn - glycero-3-phosphocholines (platelet activating factor). These results indicate that the metabolic pathway for alkylacetylglycerols involves reaction steps catalyzed by the following enzymatic activities: choline- and ethanolamine-phosphotransferases, acetyl-hydrolase, an acyltransferase, and a phosphotransferase. The step responsible for the biosynthesis of platelet activating factor would appear to be the most important reaction in this pathway and this product could explain the hypotensive activities previously described for alkylacetyl-(or propionyl)-glycerols. Of particular interest was the preference exhibited for the utilization of the 1-hexadecyl-2-acetyl- sn - glycerol species in the formation of platelet activating factor.
Detection and Characterization of Peroxynitrite-Induced Modifications of Tyrosine, Tryptophan, and Methionine Residues by Tandem Mass Spectrometry

Nitration and oxidation of tyrosine, tryptophan, and methionine residues in proteins are potential markers of their interaction with peroxynitrite. This chapter describes the procedure for the detection of these nitro-oxidative modifications by tandem mass spectrometry. The peptide YGDLANWMIPGK, shown to contain a nitrohydroxytryptophan in the mitochondrial enzyme succinyl-CoA:3-ketoacid coenzyme A transferase (SCOT) in vivo, was synthesized and exposed to peroxynitrite in order to test whether an identical tryptophan derivative could be generated in vitro. Data show that the occurrence of specific fragmented ions corresponding to the oxidation of methionine, nitration of tyrosine, and nitration/oxidation of tryptophan residues can be used to identify the sites of the nitration and oxidation of proteins in vitro and in vivo. It is also demonstrated that a nitrohydroxy addition to the tryptophan, similar to that present in SCOT in vivo, can be produced in vitro.
Controlling the Internet: a survey and some new results

In the past, significant progress has been made in the mathematical modelling of congestion control and congestion feedback mechanisms in the Internet. The resulting models have proved to be very useful in improving existing control and feedback mechanisms, and to make them scalable to networks that operate at very high speeds. Tools from convex optimization, control theory and stochastic processes have played a major role in the development of this Internet congestion control theory. In this paper, we focus on the control-theoretic aspects of the theory, and review some recent developments in the design of stable, scalable congestion control mechanisms. We also present a new scheme that can improve the performance of the Internet with minimal changes to the current architecture.
A (Different) Virtue Epistemology

Section 1 articulates a genus-species claim: that knowledge is a kind of success from ability. Equivalently: In cases of knowledge, S’s success in believing the truth is attributable to S’s ability. That idea is then applied to questions about the nature and value of knowledge. Section 2 asks what it would take to turn the genus-species claim into a proper theory of knowledge; that is, into informative, necessary and sufficient conditions. That question is raised in the context of an important line of objection against even the genus-species claim; namely, that there is no way to understand the attribution relation so that it does all the work that it is supposed to do. Section 3 reviews several extant proposals for understanding the attribution relation, and argues that none of them are adequate for answering the objection. Section 4 proposes a different way of understanding the relation, and shows how the resulting view does resolve the objection. Section 5 completes the new account by proposing a way to understand intellectual abilities. Section 6 briefly addresses Barn Facade cases and lottery propositions. Section 7 briefly addresses a question about the scope of knowledge; in particular, it shows how the new view allows a neo-Moorean response to skepticism.
The SAS-3 programmable telemetry system

Basic concept, system design and operation principles of the telemetry system developed for the Small Astronomy Satellite-3 (SAS-3) are analyzed. The concept of programmable format selected for the SAS-3 represents an optical combination of the fixed format system of SAS-1 and SAS-2, and the adaptive format concept. The programmable telemetry system permits a very wide range of changes in the data sampling order by a ground control station, depending on the experimental requirements, so that the maximal amount of useful data can be returned from orbit. The programmable system also allows the data format to differ from one spacecraft to another without changing hardware. Attention is given to the command requirements and redundancy of the SAS-3 telemetry system.
Cell death in the midbrain of the murine mutation weaver

The midbrain of the adult homozygous weaver (wv/wv) mouse is notable for a reduction in the numbers of dopamine-containing cells in the substantia nigra (A9) and the retrorubral nucleus (A8). We have determined that the reduction in tyrosine hydroxylase (TH)-positive neurons in the ventral midbrain of the weaver is attributable to the loss of neurons after postnatal day 7 (P7). Because the number and spatial distribution of TH-positive mesencephalic neurons in wv/wv, heterozygous weavers (+/wv), and wild-type mice are not significantly different on P7, we conclude that the early developmental steps of proliferation and migration have taken place normally in the mutant. Although numbers and distribution of cells are normal in the wv/wv on P7, the appearance of the TH-stained ventral midbrain is abnormal because of the paucity of TH-stained dendritic processes. The ventrally extending TH-positive dendrites are largely absent in the young wv/wv. The wv/wv also can be distinguished from both homozygous normal (+/+) and wv/wv littermates on P7 based on the appearance of dendrites that are more numerous than in the wv/wv but thin, disorganized, and sparse compared with +/+. Most cell death seems to take place in wv/wv before P21. However, at least one subset of dopamine-containing neurons disappears later. The zone of densely packed TH-positive neurons in the substantia nigra that is likely to be the origin of innervation to striosomes in the caudoputamen disappears between P21 and adulthood. Despite the early pathology evident in the mesencephalic dopamine- producing neurons of the +/wv, no evidence for cell death was observed there even in the oldest +/wv weavers studied.
The reduction of sampling noise in switched-capacitor circuits through spatial oversampling

A fundamental limit to the switched-capacitor design of A/D converters has been thought to be the sampling or kT/C noise on the input capacitor. Such a limitation imposes a lower bound on capacitor sizes, and hence an upper bound on the maximum possible sampling rate. However, it is shown here that sampling noise need not be a fundamental limit, and that many times the performance of existing A/D converters is possible.
A method for nonasymptotic performance analyses of array signal processing algorithms

This work features a stochastic perturbation theoretic approach that can be used to calculate the performance analyses of array signal processing algorithms for the nonasymptotically large, moderate data regimes that are appropriate for many practical system applications. As an example, the perturbation method is used to develop the expressions for the moments of the MUSIC null spectrum at moderate SNR for independent data snapshot numbers as low as /spl sim/5. Theoretical predictions are shown to be in good agreement with empirical statistical simulation results. >
Comparison of Methyllidocaine and Lidocaine on Arrhythmias Produced by Coronary Occlusion in the Dog

Methyllidocaine, a quarternary ammonium derivative of lidocaine, was tested as a treatment for the ventricular ectopic beats occurring in unanesthetized dogs 24 hours after two-stage ligation of the anterior descending branch of the left coronary artery. The electrocardiogram (lead II) and electroencephalogram were recorded. Methyllidocaine (4 and 8 mg/kg) injected i.v. during a 1-min period produced a significant reduction in ectopic beats with no significant increase in EEG activity. Lidocaine (4 and 8 mg/kg) administered similarly caused similar antiarrhythmic effects but produced a significant increase in EEG activity. A dose of 8 mg/kg caused tonic-clonic seizures in three of five dogs. Both drugs were also given i.v. (15 mg/kg) to unanesthetized cats. Methyllidocaine did not induce convulsions in four of four animals whereas lidocaine induced convulsions in three of three animals. It is concluded that methyllidocaine is as effective an antiarrhythmic agent as lidocaine but does not possess the central nervous system excitatory actions observed with lidocaine.
Imaging Through a Randomly Inhomogeneous Medium by Wavefront Reconstruction

When an object and collecting pupil are separated by a medium that has random spatial and temporal variations of refractive index, a conventionally formed image may be severely degraded over the entire field of view of the imaging system. By using lensless Fourier-transform holography, considerable improvement of image resolution can be obtained within a limited field of view. The nature of the degradation of the reconstructed images is analyzed for both long and short exposures under the assumption that the random log amplitude and phase fluctuations across the collecting pupil are locally stationary processes with gaussian statistics. Experimental results support the analysis in a qualitative manner.
Predator prey size relationship between Pseudopleuronectes americanus and Carcinus maenas

Abstract Young-of-year flatfish grow through a series of critical periods in which they are vulnerable to different predators, including decapod crustaceans. The purpose of this study was to determine if winter flounder, Pseudopleuronectes americanus , were vulnerable to one such decapod, the green crab, Carcinus maenas , and to determine if vulnerability differed between wild and cultured fish. To examine the predator–prey size relationship, an experiment was conducted in which six cultured and three wild winter flounder size class treatments were tested against six crab size class treatments. Flounder of all size classes were preyed on by all size classes of green crabs; however, mortality was highest when the largest crabs were matched with the smallest flounder. The number of flounder killed per day was significantly higher (31%) in winter flounder 20 mm should be released to promote post-release survival.
Conventional and hydrocolonic US of the appendix with CT correlation performed by on-call radiology residents.

Abstract Rationale and Objectives The purpose of this study was to assess the feasibility and accuracy of emergent hydrocolonic ultrasonography (US) performed by on-call residents in patients suspected of having appendicitis. Materials and Methods Thirty-one patients with a clinically equivocal diagnosis of appendicitis were prospectively evaluated with conventional US, hydrocolonic US, and appendiceal computed tomography (CT). Midlevel radiology residents performed the US examinations while they were on call. Sensitivity, specificity, and accuracy for diagnosing appendicitis were calculated for conventional and hydrocolonic US by using clinical outcome as the standard. Results of US and CT of the appendix were also correlated. Residents recorded their diagnostic confidence for conventional and hydrocolonic US. All patients were able to hold the rectally administered contrast material until completion of both hydrocolonic US and appendiceal CT. Results The sensitivity for detecting appendicitis with conventional US, hydrocolonic US, and appendiceal CT was 50%, 75%, and 100%, respectively. Specificity was 96%, 93%, and 93%, respectively. Identification of the normal and abnormal appendix improved from 13% (four of 31 patients) with conventional US to 35% (11 of 31 patients) with hydrocolonic US. The radiology residents' diagnostic confidence increased from 0.74 with conventional US to 0.83 with hydrocolonic US. Conclusion Hydrocolonic US is a feasible addition to conventional US examination for patients suspected of having appendicitis. It improves sensitivity, increases radiology residents' confidence, and is well tolerated by patients.
The deposition of trace metal-containing particles in the Los Angeles Area

Abstract Measurements were made of deposition from the free atmosphere of lead, zinc and cadmium on flat teflon plates. To determine the mechanisms of deposition, simultaneous measurements were made of the airborne size distributions of these metals by isokinetic sampling with a cascade impactor. Measurements of the airborne mass of lead, zinc and cadmium indicated 17%, 32% and 37% in the size range greater than 10 μm (aerodynamic diameter) respectively. Calculations based on these data showed about 70% of the total mass deposition for each metal was due to sedimentation of these large particles. The bulk of the airborne mass of these metals, in particles much smaller than 10 μm, played only a minor role in the deposition process.
A concentrically corrugated near-field plate

We present a concentrically corrugated near-field plate which can form a subwavelength near-field focus. The experimental plate consists of a coaxial aperture surrounded by non-periodic concentric corrugations. The measured subwavelength patterns are compared to those created by a coaxial probe with similar dimensions and are shown to be narrower. Excellent agreement between measurements and simulated results is observed. Finally, the frequency response of the plate is experimentally studied. The presented near-field plate will find applications in near-field probing.
ESTIMATION of HEAT of MOISTURE SORPTION and IMPROVED CRITERIA FOR EVALUATING MOISTURE SORPTION ISOTHERM EQUATIONS FOR FOODS

Heat of sorption of moisture on foods can be estimated from sorption isotherm equations having both moisture and temperature as independent variables. Sorption thermodynamics dictate that the heat of moisture sorption should decrease with increased moisture concentration, or increased temperature of food, provided no biological, chemical or other changes occur during sorption. This fact, and the Clausius-Clapeyron equation were used to derive two analytical formulae to evaluate the reliability of moisture sorption equations in the calculation of heat of sorption. As examples, Chung and Pfost, modified Harkins and Jura, modified Henderson, and Guggenheim-Anderson-De Boer equations at specified conditions were analyzed.
Plane wave reflection and refraction involving a finitely conducting medium

In this work the structure of electromagnetic field in a lossy conducting medium is studied in detail. The meaning of the complex angle of refraction is explained in terms of real parameters involved in this problem. The concepts are illustrated with a wave refracting from air into pure water at a frequency of 95 GHz and an incidence angle of 60/spl deg/. The approach is similar to that used to derive refraction in many electromagnetic textbooks, such as Stratton (J. A. Stratton, 1941), which has been cited in many of the textbooks published since. Our results agree with his for the real angle of the equiphase surface of the refracted fields, but we explore further subjects, including the instantaneous and time-averaged Pointing vectors.
Affective states of patients immediately preceding suicide.

COMMON sense would lead us to believe that the person who is about to take his own life is a highly terrified and distraught individual who sees death as the only escape from the intense and unbearable anxiety of seemingly unsolvable problems. It has been repeatedly pointed out, however, that many patients hospitalized as a result of suicidal gestures or suicidal ideation have been released as markedly improved only to be found dead by suicide shortly thereafter to the chagrin of their close associates.1 Although there have been numerous studies aimed at exploring the socio-psychological and psychological factors underlying self-destructive acts, there have been notably few attempts to investigate the role of altered affective states in the complex sequence of events leading to suicide. In a recent study2 systematic evaluations of consecutive suicides revealed that approximately 23 per cent were alcoholic and 45 per cent manic depressive. It has been reported that suicide is not a frequent cause of death in any clinical disorder other than affective disorder or alcoholism.3 The frequency of suicides in alcoholism has not been firmly established, although one study reported that 20 per cent of deaths in alcoholics were by suicide.4 A recent investigation has suggested a probable association between affective disorder and alcoholism.5 Only in the past few years has any concerted effort been made to develop a theory of suicide which might account for self-destructive acts in terms of both intentionality and altered affective states. Two recent investigations 637 have provided findings which suggest that prior to suicide the individual undergoes a change in affective reactivity. According to the theory of suicide upon which these studies were based, serious thoughts of suicide are initially accompanied by emotional turmoil as the individual stands in dread of the ramifications of his contemplated act. However, if the conflict about suicide continues, there is, over a period of time, a peaking of dread, followed by a decline below a normal level
Nonisothermal laminar contracted flow

Temperature and velocity profiles and pressure losses were computed for laminar, temperature-dependent Newtonian flow from a stream tube through an abrupt contraction into and through the entrance region of a smaller coaxial tube, in which the fluid was cooled or heated at constant wall temperature. The equations of motion and energy, including axial diffusion and viscous dissipation, were solved numerically for diameter ratios of one and two, a practical temperature range, and NPe and NRe up to 100. Entrance temperatures and velocities are far from uniform, and pressure losses are greater than those computed using simplified equations and uniform entrance temperatures and velocities.
Quantitative responses of spinothalamic lamina I neurones to graded mechanical stimulation in the cat

Nociceptive spinothalamic tract (STT) neurones in lamina I of the lumbosacral spinal cord of anaesthetized cats were characterized by recording their responses to graded mechanical stimulation with controlled forces of 10-120 g and probes of 5.0, 0.5 and 0.1 mm2 contact area. Neurones were identified by antidromic activation from the contralateral thalamus, and cells that responded to noxious stimulation were categorized as either nociceptive specific (NS, n= 20) or as polymodal nociceptive (HPC, responsive to heat, pinch and cold, n= 19) based on their responses to quantitative thermal stimuli. The mean responses of the 39 units increased linearly as stimulus intensity increased, and the population stimulus-response curves evoked by each of the three probes were all significantly different from each other. Thresholds were 45 g for the 5.0 mm2 probe, 30 g for the 0.5 mm2 probe and 20 g for the 0.1 mm2 probe. Further analysis showed that the NS neurones encoded both stimulus intensity and area (probe size) significantly better than HPC neurones in terms of their thresholds to individual probes, their peak discharge rates, their suprathreshold responsiveness and their ability to discriminate the three different probe sizes. These differences are consistent with the known differences between the mechanical encoding properties of A-fibre nociceptors, which provide the dominant inputs to NS neurones, and C-fibre nociceptors, which are the dominant inputs to HPC cells. Comparison of the stimulus-response curves of NS and HPC neurones indicated that the discharge of NS neurones better match the psychophysics of mechanical pain sensations in humans than the discharge of the HPC neurones do. Our findings support the view that NS neurones have a prominent role in mechanical pain and sharpness, and they corroborate the concept that the lamina I STT projection comprises several discrete channels that are integrated in the forebrain to generate qualitatively distinct sensations.
Thermostability of human α-l-fucosidase. Relationship to fucosidosis and low-activity serum α-l-fucosidase

Abstract Thermostability studies have been performed at different preincubation temperatures (37–65°C) on human α- l -fucosidases (α- l -fucoside fucohydrolase, EC 3.2.1.51), purified serum and liver enzyme, the isoelectric forms of purified liver enzyme which were separated by preparative isoelectric focusing, crude adult and fetal liver supernatant enzyme and neuraminidase-treated enzyme. Very different thermostability curves were found for the various isoelectric forms of α- l -fucosidase. The most neutral form (I) is least thermostable and the most acidic form (VIII) most thermostable, with the intervening forms (II–VII) having intermediate thermostabilities. For the isoelectric forms of liver α- l -fucosidase there appears to be a significant trend of increasing thermostability with increasing acidity (and presumably, increasing amounts of sialic acid). In order to determine what role, if any, sialic acid plays in determining the thermostability of α- l -fucosidase, comparative thermostability studies were performed on α- l -fucosidases from different human tissues which are reported to contain varying amounts of sialic acid. The purified sialic acid-rich serum enzyme is considerably more thermostable than the purified liver enzyme. The fetal liver enzyme (which is less acidic and may contain less sialic acid than the adult liver enzyme) is less thermostable than adult liver α- l -fucosidase. In contrast to all of the above findings which suggest that sialic acid confers thermostability to α- l -fucosidase, neuraminidase treatment of human liver α- l -fucosidase did not change its thermostability, even when considerable desialylation occurred as monitored by isoelectric focusing. The reason for these apparently inconsistent findings is not clear at the present time but several possible interpretations of the data are given.
Isolation of myoblastic, fibro-adipogenic, and fibroblastic clonal cell lines from a common precursor and study of their requirements for growth and differentiation☆

Abstract C17-S1-D-T984 (to be referred to as T984) is a myogenic clonal cell line isolated from a mouse teratocarcinoma. T984 exhibits phenotypic instability since it gives rise not only to myogenic but also to fibro-adipogenic and fibroblastic clones. A cell line of each clone type has been established and studied with respect to (1) phenotypic expression and stability; and (2) growth and differentiation in serum-free and serum-supplemented media. In both respects, marked differences between the three cell lines were observed. All three cell lines respond by increased growth in serum-free media to insulin, transferrin, fibroblast growth factor (FGF) and the serum-spreading factor of Holmes. The fibroblastic and the fibro-adipogenic cell lines can both be grown indefinitely in a serum-free medium which contains the above factors. The fibro-adipogenic cell line, which differentiates in serum-supplemented medium, exhibits very limited differentiation in the absence of serum; the serum factor(s) required for adipogenic differentiation is (are) probably proteins of molecular weight superior to 10 000. In direct contrast, the myogenic cell line exhibits limited growth in serum-free medium but readily differentiates under these conditions. Moreover, myogenic differentiation could be obtained in the defined medium at very low densities and was not influenced by the addition of medium conditioned by cells seeded at high densities. Thus, in this system, muscular differentiation is apparently independent of diffusible endogenous or exogenous factors and is probably triggered by the arrest of growth. While our results do not explain the reason why T984 exhibits phenotypic instability, they do indicate that this clonal cell line and its clonal derivatives could be used to identify the factors that influence the growth and the differentiation of cells of different mesenchymal phenotypes. The possible relationship of phenotypic instability to muscular dystrophies is also discussed.
An empirical study of comfort afforded by various hearing protection devices: Laboratory versus field results

Abstract Two studies, each using 40 subjects and four hearing protection devices (HPD), of which three were common to both studies, were conducted to assess perceived user comfort based on multidimensional bipolar rating scales in controlled laboratory and industrial field settings. Subjective comfort data were obtained in conjunction with psychophysical attenuation results reported elsewhere for both studies. The behavioral laboratory experiment investigated the effects of fitting procedure, activity movement, and HPD wearing time on first-time HPD user comfort, while the field study determined actual comfort achieved by noise-exposed industrial workers who used HPDs on the job. In the field study, subjects were pulled from their workplaces without prior knowledge of when they were to be tested and without readjusting the fit of their HPDs. The results of statistical analyses indicated that user-rated comfort achieved with the earplugs (particularly a foam earplug) was noticeably sensitive to different fitting procedures, whereas the earmuff and the ear canal cap devices were resistant to the fitting effect. In the laboratory study, perceived HPD comfort degraded significantly over a 2-h wearing period for the earmuff devices, while the earplugs provided more consistent comfort over the period. Among the four single HPDs, the most and the least comfortable, judged by the subjects, were the foam earplug and the canal cap, respectively. The field study comfort results did not validate those of the laboratory study, implying that it may be infeasible to devise a reliable short-term laboratory test which realistically estimates field HPD comfort.
Set terrain-based optimal speed limits for heavy trucks energy saving

In this paper, the benefit of setting optimal speed limits according to roadway geometry in minimising heavy truck fuel consumption is investigated and is proposed to replace constant speed limits. The optimal speed limits are set with reference to the truck’s optimal speed trajectory, which is calculated by using a constrained Nonlinear Programming (NLP) solver to minimise the truck fuel consumption and travel time based on the road geometry. The developed truck model has a standard weight-to-power ratio for highway control design and performs the speed trajectory calculated by the NLP solver for real roads. Simulation results show that truck driving at the optimal speed velocity is able to significantly reduce fuel consumption with small travel time increases, when compared to constant speed cruise driving. Thus, the implementation of the optimal speed limits based on terrain variation could save heavy trucks’ fuel consumption.
W-band imager without mechanical scanning based on an echelle spectrometer

We describe a two-dimensional imager in W-band using a single heterodyne transceiver and no mechanical scanning. By using an echelle grating spectrometer, frequencies are mapped onto a 2-D surface in space, so that spectral analysis of the signals provides a two-dimensional image.
Corrigendum to “Interleukin-6 Directly Impairs the Erythroid Development of Human TF-1 Erythroleukemic Cells” [Blood Cells Mol. Dis. 52 (2) (2014)]

a Division of Geriatric Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA b Center for Stem Cell Biology & Regenerative Medicine and Departments of Pediatrics and Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA c Lowe Family Genomics Core, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA d Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
Wayward Girls and Virtuous Women: Social Workers and Female Juvenile Delinquency in the Progressive Era

In the Progressive Era, many immigrant and working-class girls were tried for crimes of immorality, were confined to reformatories, and were sometimes forced to undergo sterilization. This article discusses social workers' relationship to these practices that criminalized adolescent female sexuality by examining two branches of the burgeoning profession: the social reformers and the caseworkers.
The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans

A general argument is made for the photochemical origins of life. A constant flux of free energy is required to maintain the organized state of matter called life. Solar photons are the unique source of the large amounts of energy probably required to initiate this organization and certainly required for the evolution of life to occur. The completion of this argument will require the experimental determination of suitable photochemical reactions. It is shown that biogenetic porphyrins readily photooxidize substrates and emit hydrogen in the presence of a catalyst. These results are consistent with the Granick hypothesis, which relates a biosynthetic pathway to its evolutionary origin. It has been shown that photoexcitation of ferrous ion at neutral pH with near ultraviolet light produces hydrogen with high quantum yield. This same simple system may reduce carbon dioxide to formaldehyde and further products. These reactions offer a solution to the dilemma confronting the Oparin-Urey-Miller model of the chemical origin of life. If carbon dioxide is the main form of carbon on the primitive earth, the ferrous photoreaction may provide the reduced carbon necessary for the formation of amino acids and other biogenic molecules. These results suggest that this progenitor of modern photosynthesis may have contributed to the chemical origins of life.
Spectrophotometric assay of mefenamic acid in tablets using 1,4-dioxane as solvent for extraction

A spectrophotometric method of assay of mefenamic acid in tablets involving, dissolving the tablet powder in 1,4-dioxane and measuring the absorbance at 353.2 nm. The concentration of mefenamic acid is determined using the previously prepared calibration curve using standard solution of mefenamic acid in dioxane. The method was tested by assay of six different commercial tablets containing mefenamic acid.
Effect of intramolecular reactions in multifunctional step growth polymerizations in cascades of continuous‐flow, stirred‐tank reactors

A simple kinetic model describing intramolecular reactions in multifunctional step growth polymerizations of RA j monomers is presented. The model is far simpler than more detailed kinetic or Monte Carlo models which pose severe numerical difficulties close to gelation. The formulation presented is quite general, but it requires a relationship for the ensemble-cum-time average number of rings, r n , per molecule having n RA j units. A very simple yet intuitively correct equation has been chosen for r n , which involves an empirical parameter A Results on cascades of homogeneous continuous-flow stirred-tank reactors (HCSTRs) show trends which are physically expected. The present formulation could possibly be used for scale-up of HCSTRs, with obtained experimentally. It is hoped that future studies using rigorous models would lead to more fundamental and improved relationships for r n .
The inhibitory effect of paraquat on histamine and isoproterenol induced changes of cyclic nucleotides in rat lung slices.

The incubation of rat lung slices with paraquat ion (10−4 M) had no effect on cAMP and cGMP levels of the rat lung slices. The preincubation with the same concentration of paraquat inhibited the cAMP elevating effect of histamine (10−5 M) and isoproterenol (10−5 M) and reduced the cGMP level to approximately 50% of the level obtained without preincubation with paraquat.
Contour suppression during stroboscopic motion and metacontrast.

Abstract Findings of visual contour masking obtained when two stationary and spatially separated stimuli are presented briefly and successively in time indicate that the contour masking typically observed while viewing a stimulus in real movement also occurs while viewing a stimulus in stroboscopic movement. Additional results indicate that the loss of detailed contour information attending stroboscopic movement may contribute to. though not constitute, the contour suppression effects observed in metacontrast.
Ultralarge von Willebrand factor multimers and normal ADAMTS13 activity in the umbilical cord blood

Abstract Introduction: Recent studies demonstrate that deficiency of ADAMTS13, the metalloprotease that cleaves von Willebrand factor (VWF) in a shear-dependent manner, causes thrombotic thrombocytopenic purpura (TTP). Previously, ultralarge multimers of VWF were detected in the fetuses, the umbilical cords and the newborns. However, the significance of this finding is unknown. Materials and methods: The activity of ADAMTS13 and the multimer pattern of VWF in the cord blood, as well as the VWF antigenic and ristocetin cofactor levels, were analyzed using previously published methods. The presence of ultralarge multimers was determined by densitometric analysis. Results: On the average, the level of VWF antigen and ristocetin cofactor activity are slightly increased in the newborns (mean±standard deviation, 1.66±0.76 and 1.45±0.64 U/ml, respectively). Ultralarge VWF multimers are detected in 11 of 17 umbilical cord plasma samples. However, the ADAMTS13 is normal (0.99±0.15 U/ml) in all but one sample in which it is mildly decreased (0.71 U/ml). Conclusions: Since ADAMTS13 activity is normal, we speculate that the presence of ultralarge multimers in the umbilical cord blood may be due to the low levels of shear stress in the umbilical circulation. These results may have important implications for understanding the manifestation of ADAMTS13 deficiency during the neonatal period.
Coverage probability of uplink cellular networks

The cellular uplink has typically been studied using simple Wyner-type analytical models where interference is modeled as a constant or a single random variable, or via complex system-level simulations for a given set of parameters, which are often insufficient to evaluate performance in all operational regimes. In this paper, we take a fresh look at this classic problem using tools from point process theory and stochastic geometry, and develop a new tractable model for the cellular uplink which provides easy-to-evaluate expressions for important performance metrics such as coverage probability. The main idea is to model the locations of mobiles as a realization of a Poisson Point Process where each base station (BS) is located uniformly in the Voronoi cell of the mobile it serves, thereby capturing the dependence in two spatial processes. In addition to modeling interference accurately, it provides a natural way to model per-mobile power control, which is an important aspect of the uplink and one of the reasons why uplink analysis is more involved than its downlink counterpart. We also show that the same framework can be used to study regular as well as irregular BS deployments by choosing an appropriate distribution for the distance of a mobile to its serving BS. We verify the accuracy of this framework with an actual urban/suburban cellular network.
Origins and nature of vessels in monocotyledons. 2. Juncaginaceae and Scheuchzeriaceae

SEM studies of roots and rhizomes of Triglochin (one species) and Maundia (monotypic) of Juncaginaceae and the sole species of Scheuchzeriaceae, Scheuchzeria palustris, reveals that vessels are present not only in roots, as previously reported, but also in rhizomes. The perforations contain pit membranes with pores of various sizes. Striate pit membranes, like those previously seen in Acorus, occur on pit remnants in peforations and on pit membranes of lateral walls in all genera studied. Grooves interconnecting pit apertures are illustrated for root tracheary elements of Triglochin; this is believed to be a first report of this feature for monocotyledons. The tracheary elements of Juncaginaceae and Scheuchzeriaceae are similar in their thick walls and narrow slitlike pits, lending support to the close relationship between the two families often claimed.
Moment method solutions using parametric geometry

A technique for computing the electromagnetic (EM) radiation and scattering from three-dimensional (3D) conducting bodies of general shape is presented. The arbitrary surface is described by dividing it into a number of connected patches which are mathematically described as parametric quadratic surfaces. The electric field integral equation (EFIE) is discretized by the standard method of moments (MOM) with specially designed basis functions for subdomains which now contain surface curvature. The use of the basis functions on curvilinear patch reduces the number of unknowns used in MOM.
Electrical injection in longitudinal and coaxial heterostructure nanowires: A comparative study through a three-dimensional simulation

We carried out a comparative study of electrical injection in longitudinal p-i-n and coaxial p-n core-shell nanowires by performing a three-dimensional numerical simulation. In the case of the core-shell structure, we show that both electrons and holes of high density can be efficiently injected into and confined in the structure even without an i-region. The required bias voltage and doping concentrations in the core-shell structure are smaller than those in the longitudinal p-i-n structure to achieve the same carrier injection level. Furthermore, we show that a type-I band alignment, as required in traditional p-i-n structure is not necessary in core-shell structure, allowing more flexibility in nanowire devices design. Our results thus provide a theoretical foundation and understanding that a core-shell structure is far superior to the longitudinal p-i-n structure for electrical injection nanowire lasers.
Dual Cities? Sectoral Shifts and Metropolitan Income Inequality, 1980–90

The sectoral shift from manufacturing to services is one of several potential explanations for increasing income inequality in the United States. This article reframes national-level explanations of rising inequality at the level of urban labour markets and assesses their relative contributions to levels and trends in metropolitan income inequality. We find that sectoral shifts, especially the rates of deindustrialisation and employment growth in personal services, significantly affect changes in Gini indices for the largest constant-boundary MSAs between 1980 and 1990. In addition, rising metropolitan inequality is associated with the trend towards self-employment and such supply-side factors as local education levels, changing family structure and immigration. The study provides mixed support for the mismatch and global cities hypotheses.
Chemopreventive agent-induced modulation of death receptors

The goals of chemoprevention of cancer are to inhibit the initiation or suppress the promotion and progression of preneoplastic lesions to invasive cancer through the use specific natural or synthetic agents. Therefore, a more desirable and aggressive approach is to eliminate aberrant clones by inducing apoptosis rather than merely slowing down their proliferation. The increased understanding of apoptosis pathways has directed attention to components of these pathways as potential targets not only for chemotherapeutic but also for chemopreventive agents. Activation of death receptors triggers an extrinsic apoptotic pathway, which plays a critical role in tumor immunosurveillance. An increasing number of previously identified chemopreventive agents were found to induce apoptosis in a variety of premalignant and malignant cell types in vitro and in a few animal models in vivo. Some chemopreventive agents such as non-steroidal anti-inflammatory drugs, tritepenoids, and retinoids increase the expression of death receptors. Thus, understanding the modulation of death receptors by chemopreventive agents and their implications in chemoprevention may provide a rational approach for using such agents alone or in combination with other agents to enhance death receptor-mediated apoptosis as a strategy for effective chemoprevention of cancer.
Interactions of antiepileptic drugs on adenylate cyclase and phosphodiesterases in rat and mouse cerebrum.

Five anticonvulsant agents were tested in broken cellular preparations of mouse and rat cerebral cortex for their ability to modify either adenylate cyclase or three forms of cyclic AMP-dependent phosphodiesterase. In both species only carbamazepine inhibited the stimulation of cortical adenylate cyclase by catecholamines (norepinephrine and/or dopamine). Two benzodiazepines, diazepam and clonazepam, enhanced basal and catecholamine-stimulated adenylate cyclase. The latter observations were expecially prominent when phosphodiesterase inhibitors were removed from the preparations. In all instances diazepam was more potent than clonazepam and additionally exerted a more pronounced blockade of high and low Km phosphodiesterase (mouse cerebrum) and the Ca2+-dependent, heatstable, activated phosphodiesterase in the rat cortex. Of the other anticonvulsants evaluated (carbamazepine, phenytoin, and phenobarbital), only phenobarbital inhibited phosphodiesterase, i.e., the low Km form.
Improved ajmalicine production and recovery from Catharanthus roseus suspensions with increased product removal rates

Abstract The potential of strategies for increasing secondary metabolite accumulation from plant cell cultures may still be partially limited by unfavorable conditions for biosynthesis (i.e. feedback inhibition, unfavorable equilibrium state) or product metabolism. In this paper, the rate of product removal was altered and used as a tool for probing the impact of these limiting conditions on product accumulation, using the production of ajmalicine and serpentine from Catharanthus roseus suspensions as a model system. The method for altering the in situ product removal rate was simple; Amberlite® XAD-7HP resin was enclosed in either a porous or less porous material, and experiments confirmed that the product removal rate was higher with resin enclosed in the porous Miracloth versus the less porous nylon. When resin was added to suspensions, higher ajmalicine production and recovery were associated with Miracloth-enclosed resin which had higher product removal rates. This simple experiment illustrated that further improvements in production and recovery were possible, indicating that conditions unfavorable for biosynthesis and/or product metabolism existed in cultures with nylon-enclosed resin. These results also suggest the importance of optimizing the product removal rate for improving the overall production and recovery of secondary metabolites from plant cell cultures.
Electrochemical Cyclization of Dipeptides To Form Novel Bicyclic, Reverse-Turn Peptidomimetics. 2. Synthesis and Conformational Analysis of 6,5-Bicyclic Systems

Novel, highly constrained, 6,5-bicyclic dipeptides (1-aza-5-oxa-2-oxobicyclo[4.3.0]nonane ring skeletons, 2) have been synthesized by a one-step electrochemical cyclization from the dipeptides Boc-(S)-serine-(S)-proline-OMe (Boc-(S)-Ser-(S)-Pro-OMe, 3) and Boc-(R,S)-α-methylserine-(S)-proline-OMe (Boc-(R,S)-α-MeS-(S)-Pro-OMe, 12) in yields of 10−25% and 41%, respectively. The one-pot reaction uses selective anodic amide oxidation to generate an N-acyliminium cation which is trapped by an intramolecular hydroxyl group. The cyclization of Boc-(S)-Ser-(S)-Pro-OMe (3) to the 6,5-bicyclic skeleton 4 was highly diastereoselective, generating a new chiral center with an S configuration. This bicyclic compound was sufficiently stable to trifluoroacetic acid and anhydrous hydrofluoric acid for use in standard solid phase peptide synthesis methodologies. Oxidation of Boc-(R,S)-MeS-(S)-Pro-OMe (12) gave different results for each diastereoisomer. Cyclization only occurred for the S,S-diastereoisomer with very low st...
Highly structured sequence homology between an insertion element and the gene in which it resides

The recessive allele for soybean seed lectin results from the insertion of a DNA segment (designated Tgm1) into the coding region of the gene. The termini of Tgm1 display structural features characteristic of a transposable element. The complete sequence of Tgm1 contains 3550 base pairs (bp) and can be divided into three regions (left arm, mid-section, and right arm). No large open reading frames were found, but an extensive, highly structured border with homology to the lectin gene was revealed. The left border (726 bp) comprising most of the left arm and extreme right border (144 bp) of the right arm consist of various forms of a basic 54-bp repeating unit. This 54-bp unit is comprised of a stem-loop structure and interhairpin sequence that occurs 13 times in the left arm and 2 times in the right arm of Tgm1. Progressively degenerate forms of this repeating unit appear toward the termini of Tgm1, but the dyad symmetry remains highly conserved. Seven nucleotides (A-C-A-T-C-G-G and its complement) maintained within the stem also appear as a subset of inverted repeats found at nearly equal distances from the target site in the lectin gene. Together with the inverted repeat termini and a duplication in the left arm, this 7-bp sequence occurs a total of 33 times in Tgm1. We infer that the dyad symmetries containing this sequence are involved in target gene selection. The repeating unit format of Tgm1 describes a distinct class of eukaryotic elements that includes representatives known to be mobile in snapdragon and maize.
Free surface and solid boundary effects on the free vibration of cantilevered composite plates

Abstract This paper investigates the effects of surrounding boundaries on the free vibration response of fully and partially submerged cantilevered composite plates and how these effects change due to material anisotropy. The results show that added mass significantly reduces the natural frequencies of cantilevered marine structures as a function of relative submergence depth, more so for composite plates than for steel plates because of the much lower ratio of effective structural mass to hydrodynamic added mass. Added mass effects are most dramatic for partially submerged plates as the plates move from being above to completely beneath the free surface. Free surface effects are shown to become negligible for a fully submerged plate parallel to the free surface when the depth of submergence exceeds 50% of the plate length. Solid boundaries are found to have limited effects for fully-submerged plates near a wall, where maximum decreases in resonance frequencies due to increases in added mass are only a few percent.