cssi/SciSciGPT-SciSciNet huggingface dataset:
Oxidation-reduction properties of flavodoxin from Peptostreptococcus elsdenii.

Abstract Peptostreptococcus elsdenii flavodoxin is completely reduced by 1 mole of sodium dithionite per mole of proteinbound flavin mononucleotide; 0.5 mole of dithionite generates almost maximum flavin semiquinone. The amount of semiquinone formed is dependent on pH. Semiquinone formation constants determined at pH 8.3 and 9.26, were 910 and 110, respectively. Fully reduced flavodoxin reacts rapidly with oxidized flavodoxin to form semiquinone. The rate of this reaction is pH-dependent and decreases from 105 m-1 min-1 at pH 6.7 to 1.6 x 104 m-1 min-1 at pH 9.26. The oxidation-reduction potential (E2) for the couple oxidized flavodoxin/flavodoxin semiquinone was determined by equilibrium experiments with indigo dyes. E2 was -0.115 volt at pH 7. The oxidation-reduction potential (E1) for the couple semiquinone/fully reduced flavodoxin was determined from the equilibrium concentration of these components after treating flavodoxin with hydrogen and hydrogenase. E1 was -0.373 volt at pH 7. A value for E1 was also obtained from the concentrations of fully reduced flavodoxin and flavodoxin semiquinone formed in equilibrium with excess TPNH in the presence of spinach ferredoxin-TPN reductase. By this method E1 was -0.371 volt at pH 7. The effect of pH on E1 suggests an ionization in fully reduced flavodoxin with a pK = 5.8. When reduced flavodoxin is mixed with air, the semiquinone is formed rapidly. Air oxidation of flavodoxin semiquinone is slow; the observed rate is markedly dependent on pH.
Estimating Item Difficulty With Comparative Judgments

Previous investigations of the ability of content experts and test developers to estimate item difficulty have, for the most part, produced disappointing results. These investigations were based on a noncomparative method of independently rating the difficulty of items. In this article, we argue that, by eliciting comparative judgments of difficulty, judges can more accurately estimate item difficulties. In this study, judges from different backgrounds rank ordered the difficulty of SAT® mathematics items in sets of 7 items. Results showed that judges are reasonably successful in rank ordering several items in terms of difficulty, with little variability across judges and content areas. Simulations of a possible implementation of comparative judgments for difficulty estimation show that it is possible to achieve high correlations between true and estimated difficulties with relatively few comparisons. Implications of these results for the test development process are discussed.
Role of Pasteurella pneumotropica and Mycoplasma pulmonis in Murine Pneumonia

Pneumonia caused by Mycoplasma pulmonis and Pasteurella pneumotropica was studied in conventional, specific pathogen-free (SPF), and germ-free mice. When P. pneumotropica was serially passed in conventional mice, M. pulmonis, as well as P. pneumotropica, was recovered from mice with gross lesions. When M. pulmonis was serially passed in conventional mice, both organisms were recovered. SPF mice given a nasal instillation of M. pulmonis alone, P. pneumotropica alone, or a combination of the two developed pneumonia when both organisms were present. These findings suggested that both organisms contribute to typical murine pneumonia. That M. pulmonis might be an L form of P. pneumotropica was suggested because some SPF mice inoculated with either organism yielded both on culture. This possibility was investigated with mole per cent guanine plus cytosine (GC) content and nucleic acid hybridization techniques. The GC content of P. pneumotropica is 42.2 mole per cent and that of M. pulmonis is 28.6 mole per cent. No specific hybrids between deoxyribonucleic acid (DNA) from M. pulmonis and DNA from P. pneumotropica were detected. This and the wide disparity in GC content showed that M. pulmonis is not an L form of P. pneumotropica. In germ-free mice, intranasal instillation with either organism alone produced pneumonia. The lesions produced when each organism was inoculated independently were characterized by areas of consolidation with perivascular and peribronchial lymphocytic infiltration. Qualitatively, the lesions produced when both organisms were inoculated simultaneously more closely resembled those seen in naturally occurring murine pneumonia. Statistical analysis indicated that the quantitative effect of the two organisms was additive. The indirect fluorescent antibody technique was used to locate organisms in lung tissue sections. M. pulmonis localized in the bronchial epithelium and P. pneumotropica localized in the alveolar lesions.
Let's Look Together: An Interactive Picture Book, by Rae-Lynn Cebul Ziegler

Let's Look Together: An Interactive Picture Book is a slim and useful resource for family members, activities directors, and speech or occupational therapists. The book is a collection of 27 color ...
Note from the President

On behalf of the Genetics Society of America I thank David Stadler and his committee members—Scott Hawley, Robert Haynes, Elizabeth Kutter and Michael Resnick—for inviting authors and overseeing the reviewing and editing of the manuscripts assembled for the special section honoring John (Jan)
Functional Morphology at the Mall

ABSTRACT The primary decorative flooring tile in the Southpark Mall in Charlotte, North Carolina, is fossiliferous limestone that contains Jurassic ammonoids and belemnoids. Visible in these tiles are more than 500 ammonoids, many of which have been cross sectioned equatorially perpendicular to the plane of coiling. Upperlevel undergraduate students from UNC Charlotte used this data set to measure ammonoid coiling geometry and, thus, coiling strategy, and their findings were compared with earlier reported research presented in highly respected paleobiology journals. This example of urban paleobiology utilized a large, easily accessible, and readily available fossil data set to introduce functional morphology of coiled cephalopods. Similar data sets are available in public buildings around the United States, providing a valuable fossil resource at a time when shrinking academic budgets would prohibit purchasing such a collection (and many collections have not been updated in decades). As students compared ...
Adolescents and Young Adult Health

Introduction Health Profile of Adolescents/Young Adults in the United States Health Risk Behavior Access to Care and Health Care Utilization Trends in the Provisionof Adolescent Health Services The Implementationof Adolescent Clinical Preventive Services Summary Keywords: health profile; mortality; homicide; suicide; disordered eating; chronic illness; health risk behavior; sexual behavior; substance use; tobacco use; illicit drugs; access to care; health care utilization; adolescent health services; prevention services
ACE Inhibitors Promote Nitric Oxide Accumulation to Modulate Myocardial Oxygen Consumption

Background ACE inhibitors potentiate kinin–nitric oxide (NO)–dependent coronary vascular dilation, and NO can modulate myocardial oxygen consumption. Whether ACE inhibitors also affect myocardial O2 consumption has not been established. Methods and Results Production of nitrite, a metabolite of NO in aqueous solution, in coronary microvessels and O2 consumption in myocardium were quantified with the use of in vitro tissue preparations, the Greiss reaction, and a Clark-type O2 electrode. In coronary microvessels, kininogen (the precursor of kinin; 10 μg/mL) and three ACE inhibitors (captopril, enalaprilat, or ramiprilat; 10−8 mol/L) increased nitrite production from 76±6 to 173±15, 123±12, 125±12, and 153±12 pmol/mg, respectively (all P <.05). In myocardium, kininogen (10 μg/mL) and captopril, enalaprilat, or ramiprilat (10−4 mol/L) reduced cardiac O2 consumption by 41±2%, 19±3%, 25±2%, and 35±2%, respectively. The changes in both nitrite release and O2 consumption in vitro were blocked by N ω-nitro-l-arginine methyl ester or N ω-nitro-l-arginine, inhibitors of endogenous NO formation. The effects were also blocked by HOE 140, which blocks the bradykinin B2-kinin receptor, and serine protease inhibitors, which inhibit local kinin formation. Conclusions Our data indicate that stimulation of local kinin formation by use of a precursor for kinin formation or inhibition of kinin degradation by use of ACE inhibitors increases NO formation and is important in the control of cardiac O2 consumption. Vasodilation and control of myocardial O2 consumption by NO may contribute importantly to the therapeutic actions of ACE inhibitors in cardiac disease states.
Impact of divalent metal cations on the catalysis of peptide bonds: a DFT study

Within the ATP-grasp family of enzymes, divalent alkaline earth metals are proposed to chelate terminal ATP phosphates and facilitate the formation of peptide bonds. Density functional theory methods are used to explore the impact of metal ions on peptide bond formation, providing an insight into experimental metal substitution studies. Calculations show that alkaline earth and transition metal cations coordinate with an acylphosphate reactant and aid in the separation of the phosphate leaving group. The critical biochemical reaction is proposed to proceed through the formation of a six-membered transition state in the relatively nonpolar active site of human glutathione synthetase, an ATP-grasp enzyme. While the identity of the metal ion has a moderate impact on the thermodynamics of peptide bond formation, kinetic differences are much sharper. Simulations indicate that several transition metal ions, most notably Cu2+, may be particularly advantageous for catalysis. The detailed mechanistic study serves ...
A Numerical Investigation of Cloud-Top Entrainment Instability and Related Experiments

Buoyancy reversal occurs between two homogeneous fluids when as a result of non-linear mixing the mixture becomes denser than either of the fluids. In 1980 both Randall and Deardorff suggested that such nonlinear mixing, which may occur across a stratocumulus cloud-top as a consequence of evaporative cooling. could create an entrainment instability; the ensuing rapid entrainment could lead to stratocumulus break-up. This break-up mechanism is known as cloud-top entrainment instability or CTEI. In 1990 Shy and Breidenthal investigated buoyancy reversal within a laboratory environment and proposed a model for turbulent entrainment, and conditions under which buoyancy reversal may lead to an entrainment instability. They found that an instability could occur only if D (the ratio of the density difference between the most cooled mixed parcel and the lower fluid to the density difference across the unmixed layers) was approximately one or larger. This restriction of a strong buoyancy reversal for an instability (hence SBRI) is more stringent than Randall's condition, D ≥ 0, and is almost never satisfied at the inversion topping a marine stratocumulus layer. We have used numerical simulations of a single eddy at an interface between two fluids to explore the entrainment model of Shy and Breidenthal. Consistent with SBRI. we find that in all cases a critical value of D, Dc, between 0.3 and 2.0 exists. For DDc, kinetic energy is found to increase on the scale of the entraining eddy. We expand the domain to model the interaction of the multiple eddies with an entrainment interface. We find a similar Dc where unstable entrainment is exhibited, and a tendency for larger eddies to develop if Dc. > D. We explore the influence of the fluid and flow characteristics on Dc to bridge the gap between the laboratory and the atmosphere. We find that Dc is lower at Schmidt numbers of order unity, characteristic of the atmosphere, than for those equal to 103, typical of the laboratory fluid. In all cases Dc remains too large to be a factor in stratocumulus break-up.
Cardiopulmonary bypass and the coagulation system

Abstract Cardiopulmonary bypass exerts intended and unintended effects on the enzymatic and formed elements of the coagulation and inflammatory systems. Compared with adults, children are at special risk for known, and unknown, differences in their hemostatic systems. Management of these risks will be presented from a surgical perspective, supporting those strategies with a combination of peer-reviewed data and empiric experience. Preoperatively, strategies discussed are management of preoperative anticoagulants, autologous and directed donation, erythropoietin, and special considerations in the care of pediatric Jehovah's Witnesses. Intraoperatively, strategies discussed include basic management of cardiopulmonary bypass, heparin and heparin monitoring, protamine, alternative anticoagulant strategies for heparin sensitivity, and intraoperative pharmacologic adjuncts promoting postoperative hemostasis. Postoperative strategies discussed include blood product utilization, recombinant factor VII, the use of thromboelastography to guide therapy, topical strategies, cell saver therapy, and surgical reexploration.
Reproductive status and adrenal size in the northern red-backed vole in relation to season.

Adrenal and gonad weights were measured in the northern red-backed vole, CLETHRIONOMYS RUTILUS, from July 1963 through August 1964 in the vicinity of College, Alaska. Relative weights of the testes and ovaries underwent a seasonal cycle which was most closely correlated with the annual light cycle. Adrenal size in female voles appeared to be strongly influenced by reproductive state and underwent a striking increase with onset of the breeding season and a corresponding decline with cessation of reproductive activities. In male voles adrenal size was not influenced by reproductive activities. The magnitude of seasonal change in adrenal size of male voles was not great and could not be definitely associated with any extrinsic factors in the environment.
A histological study of the formation and development of the soft palate in mice and man

Abstract The secondary palate was examined to determine formation of the soft palate with regard to the process of merging and/or fusion. A midline seam of epithelium was observed in the region of the future soft palate, indicating that epithelial adherence and mesenchymal fusion was occurring, and not merging. Epithelial breakdown was more rapid and complete in the presumptive soft palate and along the junction of the nasal septum and palate than in the midline of the future hard palate. Based upon these observations and other studies, the hypothesis is proposed that the medial palatal epithelium is different and/or is acted upon differently in the anterior and posterior regions of the developing secondary palate.
Interaction of antibodies with uridine diphosphosphate galactose 4-epimerase from yeast.

Antibodies from a rabbit immunized with uridinediphosphate galactose 4-epimerase were shown to inhibit the specific activity of the enzyme and to precipitate [14C]UMP-labelled epimerase. It comprised about 0.33% of the immunoglobins and its Fab fragments had a binding constant of 0.2 × 109 M-1 at 25° and 1.1 × 109 M-1 at 4°. Despite the high energy of interaction the antibody did not liberate [14C]UMP from reduced [14C]UMP-epimerase. It gave two precipitation lines both with the native and with the reduced epimerase in the immunoelectrophoresis. However, the same pattern was obtained with antibody from a UMP-epimerase immunized rabbit that could not precipitate [14C]UMP-epimerase or inhibit the enzymatic activity. It is not clear whether any of the lines represent the epimerase protein unit sensu strictu.
New measurements of photospheric magnetic fields in late-type stars and emerging trends

The magnetic fields of late-type stars are measured using the method of Saar et al. (1986). The method includes radiative transfer effects and compensation for line blending; the photospheric magnetic field parameters are derived by comparing observed and theoretical line profiles using an LTE code that includes line saturation and full Zeeman pattern. The preliminary mean active region magnetic field strengths (B) and surface area coverages for 20 stars are discussed. It is observed that there is a trend of increasing B towards the cooler dwarfs stars, and the linear correlation between B and the equipartition value of the magnetic field strength suggests that the photospheric gas pressure determines the photospheric magnetic field strengths. A tendency toward larger filling factors at larger stellar angular velocities is also detected.
The use of lead isotope ratios in estimating the age of the Earth

Since the publication of Nier's determinations of the lead isotope ratios in lead ores of different geologic horizons from Precambrian to Tertiary, four more or less independent efforts have been made to use these data as a basis for calculating the age of the Earth. In addition to the fact that more data are required to establish statistical validity for any of these methods, they all share a common fault of assuming that we already know with reasonable accuracy the age in years of one or more of these ores from their field associations. The author contends that the age of the enclosing rocks need have no correlation with the age of the ore if, by the latter, we mean the time of its extraction from source crustal rocks or magmas (not the time of its emplacement). A method is proposed for determining the age of granites in years measured backward from now instead of from the assumed age of any given rock body; and suggestions are made as to how the same data may provide a basis for determining the age of the original crust of the Earth. A least-squares analysis of the data from isotope ratios in lead ores is used to show that the maximal possible age of matter is 5.07 × 109 years. Reasons are given for thinking the real age less than that. The fact that least-squares equations, assuming alpha decay as the sole source of changes in the isotope ratios of uranium and lead in the past, can be extrapolated to the present ratio of U235/U238 with a Lagrange multiplier not significantly different from zero, is interpreted to mean that other processes than alpha decay (such as natural fission, isotopic selectivity in crystal formation, and radon loss) have played no significant role in changing the composition of the ores.
159 BIOCHEMICAL PARAMETERS OF BONE MINERAL METABOLISM IN VIEW INFANTS ON A PRETERM FORMULA OR FORTIFIED OWN MOTHER'S MILK

159 BIOCHEMICAL PARAMETERS OF BONE MINERAL METABOLISM IN VIEW INFANTS ON A PRETERM FORMULA OR FORTIFIED OWN MOTHER'S MILK
Structure and phase behavior of lipid suspensions containing phospholipids with covalently attached poly(ethylene glycol)

Liposomes containing phospholipids with covalently attached poly(ethylene glycol) (PEG-lipids) are being developed for in vivo drug delivery. In this paper we determine the structure and phase behavior of fully hydrated distearoylphosphatidylcholine (DSPC) suspensions containing PEG-lipids composed of distearoylphosphatidylethanolamine with attached PEGs of molecular weights ranging from 350 to 5000. For DSPC:PEG-lipid suspensions containing 0–60 mol % PEG-lipid, differential scanning calorimetry shows main endothermic transitions ranging from 55 to 64 degrees C, depending on the size of the PEG and concentration of PEG-lipid. The enthalpy of this main transition remains constant for all PEG-350 concentrations but decreases with increasing amounts of PEG-750, PEG-2000, or PEG-5000, ultimately disappearing at PEG-lipid concentrations greater than about 60 mol %. Low-angle and wide-angle x-ray diffraction show that tilted gel (L beta') phase bilayers are formed for all PEG-lipid molecular weights at concentrations of about 10 mol % or less, with the distance between bilayers depending on PEG molecular weight and PEG-lipid concentration. At PEG-lipid concentrations greater than 10 mol %, the lipid structure depends on the size of the PEG moiety. X-ray diffraction analysis shows that untilted interdigitated (L beta I) gel phase bilayers form with the incorporation of 40–100 mol % PEG-350 or 20–70 mol % PEG-750, and untilted gel (L beta) phase bilayers are formed in the presence of about 20–60 mol % PEG-2000 and PEG-5000. Light microscopy, turbidity measurements, x-ray diffraction, and 1H-NMR indicate that a pure micellar phase forms in the presence of greater than about 60% PEG-750, PEG-2000, or PEG-5000.
Phase resetting and its implications for interval timing with intruders.

Abstract Time perception in the second-to-minutes range is crucial for fundamental cognitive processes like decision making, rate calculation, and planning. We used a striatal beat frequency (SBF) computational model to predict the response of an interval timing network to intruders, such as gaps in conditioning stimulus (CS), or distracters presented during the uninterrupted CS. We found that, depending on the strength of the input provided to neural oscillators by the intruder, the SBF model can either ignore it or reset timing. The significant delays in timing produced by emotionally charged distracters were numerically simulated by a strong phase resetting of all neural oscillators involved in the SBF network for the entire duration of the evoked response. The combined effect of emotional distracter and pharmacological manipulations was modeled in our SBF model by modulating the firing frequencies of neural oscillators after they are released from inhibition due to emotional distracters. This article is part of a Special Issue entitled: SI: Associative and Temporal Learning.
Spectral Doubling of Normal Operators and Connections with Antiunitary Operators

Equations such as AB = B T A have been studied in the finite dimensional setting in (Linear Algebra Appl 369:279–294, 2003). These equations have implications for the spectrum of B, when A is normal. Our aim is to generalize these results to an infinite dimensional setting. In this case it is natural to use JB*J for some conjugation operator J in place of B T . Our main result is a spectral pairing theorem for a bounded normal operator B which is applied to the study of the equation KB = B*K for K an antiunitary operator. In particular, using conjugation operators, we generalize the notion of Hamiltonian operator and skew-Hamiltonian operator in a natural way, derive some of their properties, and give a characterization of certain operators B for which AB = (JB*J)A and BA = A(JB*J) and also those B with KB = B*K for certain antiunitary operators K.
Increasing male participation in the uptake of vasectomy services

In India, family planning is considered to be the woman's responsibility and tubal ligation is much more popular compared to vasectomy. For every 98 women who undergo tubal libation, only two men accept vasectomy, which reflects a serious imbalance and indicates gender inequity. About half the women in India are reported to be anaemic and a large proportion has reproductive tract infections. If not cured of reproductive tract infections, it is inappropriate for these women to undergo tubal ligation or have an intrauterine device inserted; use of contraception by husbands could be a better alternative. For men, a safe, simple and effective method of permanent contraception is No Scalpel Vasectomy (NSV). This is an improved technique over conventional vasectomy with minimal pain, no incision, no stitches and no blood loss. The entire procedure can be completed in 20 minutes and the client can leave the clinic after 1 hour. He can resume strenuous work 2 days after the procedure. It has been known for decades that the myths and misconceptions around vasectomy or NSV are the main barriers to its acceptance. People relate it to conventional vasectomy that is a relatively major procedure. They feel that NSV results in weakness such that they will not be able to do rigorous manual labour to earn their livelihood after the procedure. We conducted in-depth discussions with communities and health providers in an effort to understand what exactly they mean by weakness and why they link physical weakness with NSV. We learned that although people talk about physical weakness, their main concern is sexual weakness, which is a topic that they are hesitant to discuss. We learned that …
Perceived coercion and procedural justice in the Broward mental health court

Approximately 700,000 people with major mental disorder enter United States jails each year (U.S. Department of Justice, 1999), many of whom are arrested repeatedly for minor felonies and misdemeanors. It is increasingly assumed that their mental disorder and attendant difficulties accessing clinical services and social support programs contribute to this pattern of repeated contact with the criminal justice system. This in turn frustrates the efficiency concerns of the criminal justice system because of the extensive resources consumed by repeatedly booking, jailing, and attempting to treat these individuals in the jail setting. It also frustrates therapeutic objectives because these individuals may become increasingly distant and disengaged from their families and from community-based mental health services. The most recent innovation to address this problem has come in the form of specialty courts called mental health courts. Based somewhat on the drug court model, mental health courts vary in terms of point of intervention (e.g., preversus postadjudication), eligibility requirements (most are limited people with mental illness charged with nonviolent misdemeanors), the use of sanctions, and in other particulars (see Goldkamp & Irons-Guynn, 2000). However, all appear to have as a primary goal interrupting the cycle of repeat offending and incarceration through the expeditious processing of defendants with mental illness, providing access to treatment and social supports, and assuring public safety (Lerner-Wren, 2000). To date no mental health court has been evaluated systematically to determine its efficacy and outcomes. We are currently involved in a 2-year evaluation of the Broward County
The Logistics Of Installing Pacs In An Existing Medical Center

A largely overlooked issue in the Picture Archiving and Communication Systems (PACS) area is the tremendous amount of site planning activity required to install such a system in an existing medical center. Present PACS equipment requires significant hospital real estate, specialized electrical power, cabling, and environmental controls to operate properly. Marshaling the hospital resources necessary to install PACS equipment requires many different players. The site preparation costs are nontrivial and usually include a number of hidden expenses. This paper summarizes the experience of the University of Washington Department of Radiology in installing an extensive digital imaging network (DIN) and PACS throughout the Department and several clinics in the hospital. The major logistical problems encountered at the University are discussed, a few recommendations are made, and the installation costs are documented. Overall, the University's site preparation costs equalled about seven percent (7%) of the total PACS equipment expenditure at the site.
The Inverse Least-Squares Finite Element Method Applied to the Convection-Diffusion Equation

A Least Squares Finite Element Method (LSFEM) formulation for the detection of unknown boundary conditions in problems governed by the steady convection-diffusion equation will be presented. The method is capable of determining temperatures, and heat fluxes in location where such quantities are unknown provided such quantities are sufficiently over-specified in other locations. For the current formulation it is assumed the velocity field is known. The current formulation is unique in that it results in a sparse square system of equations even for partial differential equations that are not self-adjoint. Since this formulation always results in a symmetric positive-definite matrix, the solution can be found with standard sparse matrix solvers such as preconditioned conjugate gradient method. In addition, the formulation allows for equal order approximation of temperature and heat fluxes as it is not subject to the inf-sup condition. The formulation allow for a treatment of over-specified boundary conditions. Also, various forms of regularization can be naturally introduced within the formulation. Details of the discretization and sample results will be presented.Copyright © 2009 by ASME
OXIDATIVE PHOSPHORYLATION IN MITOCHONDRIA OF DEVELOPING RAT BRAIN

— 1 Oxygen uptake, ADP/O ratios and respiratory control ratios (RCR) were studied by oxygen electrode techniques in mitochondria prepared from developing rat brain. 2 Oxygen consumption, ADP/O ratios and RCR based on mitochondrial protein concentration increased with maturation. Of the substrates employed, succinate supported oxygen uptake best and malate poorest. 3 The addition of exogenous NAD to the mitochondrial preparation had no effect on rate of oxygen uptake. 4 Lack of change in ADP/O ratio in the presence of glucose, a tricarboxylic acid cycle intermediate (α-oxoglutarate), and ATP leads us to believe that there is no significant hexokinase activity in this preparation.
GABA acts directly on cells of pituitary pars intermedia to alter hormone output

Recent immunohistochemical evidence from the rat, indicating that γ-aminobutyric acid (GABA)-containing fibres of central nervous origin project to the pars intermedia of the pituitary1,2, prompts inquiry into the function of this innervation. There is electrophysiological evidence that GABA acts directly on melanotrophs isolated from rat, through bicuculline-blockable receptors, to increase Cl− conductance and thereby drive the membrane potential towards the Cl− equilibrium potential in these cells, resulting in depolarization at rest or reduction of the depolarization caused by excess K+ (ref. 3). As voltage-dependent Ca channels can participate in the regulation of secretion in these cells4, we have now examined the effect of GABA on hormone output and find that it first stimulates and then inhibits spontaneous secretion of melanocyte-stimulating hormone (MSH) and inhibits K+-evoked secretion. Moreover, our pharmacological evidence suggests that similar receptors are involved in the secretory and the electrophysiological responses. A function of the GABAergic innervation may therefore be to regulate hormone output by acting directly on the melanotrophs, and this regulation may be affected by the changes in electrical properties induced by GABA.
Toward computing the aspect graph of deformable generalized cylinders

The aspect graph representation of different classes of objects has been a popular research topic in the last few years. Algorithms to compute the aspect graph have been developed for polyhedra, curved-surface objects, and articulated assemblies of rigid parts. This paper discussed the problem of how to compute the aspect graph for nonrigid or deformable objects.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The midbrain tectum in visual relay

Abstract Commissures other than the corpus callosum receive very little attention as to their possible role in interhemispheric visual communication. Lyubimov's anatomical and electrophysiological study in a carnivore (dog) suggested the possibility that primary afferent optic fibers could pass through the commissure of the superior colliculus to terminate in the other superior colliculus and that visual information could be relayed via the superior colliculus by means of multisynaptic pathways from the retina to the striate cortex. Nauta preparations of 25 experimental cat brains with optic nerve sections, optic tract lesions with different surgical approaches, or superior collicular lesions were used in the present experiments to study the degrees of degeneration of the commissure. After comparing the differential results of these experiments it is concluded that primary afferent optic fibers do not pass across the commissure. Evidence from the literature does not establish the existence of pathways from the superior colliculus to the striate cortex in the manner proposed by Lyubimov. Thus it is concluded that the concept of a midbrain tectal relay of visual information from the retina to the striate cortex and of interhemispheric visual communication via the commissure of the superior colliculus does not have an adequate anatomical basis from experiments on another carnivore with a very similar general nervous organization. Some other visual relay routes are suggested in which the midbrain tectum may play a role.
Complete Galilean-Invariant Lattice BGK Models for the Navier-Stokes Equation

Galilean invariance has been an important issue in lattice-based hydrodynamics models. Previous models concentrated on the nonlinear advection term. In this paper, we take into account the nonlinear response effect in a systematic way. Using the Chapman-Enskog expansion up to second order, complete Galilean invariant lattice BGK models in one dimension (theta = 3) and two dimensions (theta = 1) for the Navier-Stokes equation have been obtained.
Corrosion of ferritic steels by molten lithium: Influence of competing thermal gradient mass transfer and surface product reactions.

Abstract An Fe-12Cr-1MoVW steel was exposed to thermally convective lithium for 6962 h. Results showed that the weight change profile of Fe-12Cr-1MoVW steel changed substantially as the maximum loop temperature was raised from 500 to 600°C. Furthermore, for a particular loop experiment, changes in the structure and composition of the exposed surfaces did not reflect typical thermal gradient mass transfer effects for all elements: the surface concentration of chromium was often a maximum at intermediate temperatures, while nickel (present at low concentrations in the starting material) tended to be transported to the coldest part of the loop. Such data were interpreted in terms of a qualitative model in which there are different dominant reactions for the various constituents of the ferritic steels (surface product formation involving nitrogen and/or carbon and solubility-driven elemental transport). This competition among different reactions is important in evaluating overall corrosion behavior and the effects of temperature. The overall corrosion rate of the 12 Cr-1MoVW steel was relatively low when compared to that for austenitic stainless steel exposed under similar conditions.
Lymphangioma-like Kaposi's sarcoma

SUMMARY Details of three patients with Kaposi's sarcoma are presented. Each case, although clinically typical, displayed unusual histological changes suggestive of lymphangioendothelioma. The significance of these changes with regard to the histogenesis of Kaposi's sarcoma is discussed.
Invariant tests for the equality of k scale parameters under spherical symmetry

Abstract We consider tests for scale parameters when the underlying distribution belongs to the class of spherically symmetric laws. A ( n x1) random vector x has a spherically symmetric distribution if the distribution of x is identical to the distribution of Px for all ( n × n ) orthogonal matrices P . Using the principle of invariance we show that the usual normal-theory tests are not only invariant tests but are also exactly robust with respect to this class of spherically symmetric laws.
Inhibition of Protein Synthesis by RA-VII

The antitumor natural product RA-VII has been evaluated as an inhibitor of protein synthesis in vitro. Complete inhibition of protein synthesis in rabbit reticulocyte lysates is observed with 5 μM RA-VII. Mechanistic studies using purified elongation factors and ribosomes identify RA-VII as a peptidyltransferase inhibitor. Thus, similar to the related natural products bouvardin and RA-XII, RA-VII appears to function by binding to eukaryotic ribosomes.
Parametric Study on the Production of Renewable Fuels and Chemicals from Phospholipid-Containing Biomass

Heterogeneous catalytic cracking of lipids into transportation fuels and other specialty chemicals offers a unique opportunity to provide sustainable energy while utilizing the current petroleum infrastructure. This study addresses a possible route for the utilization of phospholipid-containing biomass for production of renewable fuels and chemicals. The first part of the study focused on reaction pathways associated with the catalytic cracking of model phospholipid into fuel-type compounds. The results indicated that phospholipid cracking proceeds via acid-catalyzed mechanisms, which resulted to cleavage of fatty acids and glycerol moieties. Microbial lipids, which contain large concentrations of phospholipids, are a potential non-food related feedstock to displace petroleum. Among possible sources of microbial lipids, activated sludge offers a distinct advantage for its availability and abundance at a potential fee. The second part of this work dealt with the conversion of activated sludge to chemicals of value as fuel components through fluidized-bed catalytic cracking. The effect of moisture level and catalyst loading were determined. Results indicated that moisture level of up to 15 % (weight) has no effect on total product yield. On the other hand, higher catalyst loading resulted to a higher yield of gaseous product. Significant coke deposition was inferred as indicated by the high proportion of phenolic compounds produced from pyrolytic reactions. The results of this study provide a potential route of utilizing bulk lipid feedstocks, without the removal of phosphorus-containing molecules, to produce fuel components.
More than meets the eye: The circulation of images and the embodiment of value

The A. examines the popular, cheaply mass-produced prints known as calendar or bazaar art, going beyond appearances to explore how their value and power is located not just in their visuality as such, but also in their capacity as circulating objects. He describes how these prints can be seen as sites of intersection between the colonially-derived institution of fine art and what historians have called the bazaar economy. The postcolonial visual regime in which bazaar images circulate is therefore characterised by different but co-existing frames of value and moral-commercial economies. The animated circuits of bazaar icons, the A. argues, have served to shore up relations of credit and exchange in the informal social, moral-ethical and commercial networks of the bazaar, obviating the distinction between sacred and commercial forms of value. However, there are tensions between the role of images in the bazaar and the schema of aesthetic judgement within fine art. The A. focuses on the way in which performative and bodily engagements, integral to a ritual and devotional relationship with images, have been denigrated within an aesthetic schema which privileges a distanced, disembodied gaze. This paves the way for a re-examination of the notion of the fetish, asking why one of the few categories that speaks to the power of the image as a circulating object rather than as a static sign does so within a moral framework of denigration and abnormality. The A. relates this denigration to the historical conditions of this concept's appearance, and the specific ideological work it has had to do within a European bourgeois-liberal public sphere.
Beta-adrenergic influence on increased myocardial oxygen consumption during hypoxemia in awake newborn lambs.

ABSTRACT: The purpose of this investigation was to determine the role of increased s-adrenergic activity in regulating the increase in myocardial oxygen consumption that occurs during hypoxemia in unanesthetized newborn lambs. Through a left thoracotomy, fluid-filled catheters were placed in the ascending aorta, coronary sinus and left atrium, a pressure transducer was introduced into the left ventricle, and pacing wires were sutured onto the left atrium. The lambs were studied 3 d later by making intermittent measurements of aortic and coronary sinus blood oxygen saturations and Hb concentrations, left ventricular myocardial blood flow, cardiac output, heart rate, left atrial and aortic blood pressures, the maximal first derivative of left ventricular pressure, aortic and coronary sinus blood oxygen contents, the arteriovenous difference of oxygen across the left ventricular myocardium, myocardial oxygen consumption, and external cardiac work (aortic mean blood pressure times cardiac output). In nine lambs with an intact s-adrenergic nervous system (group 1), the above measurements were made during a control period and during hypoxemia (Fio2=0.08-0.10) with spontaneous tachycardia. In another group of 12 lambs (group 2), the measurements were made during a control period, after s-blockade (1.5 mg/kg intravenous propranolol) with pacing at the control heart rate, during hypoxemia with pacing at the control heart rate, and during hypoxemia with pacing-induced tachycardia. In the group 2 lambs, s-blockade completely inhibited the increase in heart rate, maximal first derivative of left ventricular pressure, cardiac output and cardiac work that occurred during hypoxemia in the group 1 lambs that had an intact s-adrenergic nervous system. In contrast, by comparing the results in groups 1 and 2, it is evident that s-blockade inhibited no more than 75-80% of the increase in myocardial oxygen consumption that occurred during hypoxemia in the group 1 lambs with an intact s-adrenergic nervous system. This study demonstrates that s-adrenergically mediated increases in heart rate, left ventricular contractility, and external cardiac work account for no more than 75-80% of the increase in myocardial oxygen consumption during hypoxemia in unanesthetized newborn lambs. The factor(s) that are responsible for the residual increase in myocardial oxygen consumption remain to be determined.
Radiographic and anatomic basis of endoscopic anterior craniocervical decompression: a comparison of endonasal, transoral, and transcervical approaches.

OBJECTIVE: To evaluate surgical access to the craniocervical junction using 3 endoscopic approaches: endonasal, transoral, and transcervical. METHODS: Nine cadaveric specimens were used. Image guidance was used in 1 specimen for each approach; fluoroscopy was used in every case. The Vitrea imaging station (Vital Images Inc., Minnetonka, MN) was used to evaluate the angles and distances to the target of the approach, centered on the tip of the odontoid. The entry site was defined as: 1 ) the endonasal approach (inferior midline of the nasal bone), 2) the transoral approach (the tip of the upper incisor), and 3) the transcervical approach (the skin at the C4-C5 level). RESULTS: Adequate lower clivus and craniocervical decompression was achieved using the endonasal and transoral approaches. Lower clivus decompression was not achieved with the transcervical approach. The average distance to the surgical target was as follows: endonasal (94 mm), transoral (102 mm), and transcervical (100 mm). The angle of attack was as follows: endonasal (28 degrees), transoral (30 degrees), and transcervical (15 degrees). The working area at the base of the field was as follows: endonasal (1305 mm 2 ), transoral (1406 mm 2 ), and transcervical (743 mm 2 ). CONCLUSION: The endonasal and transoral approaches allow wide exposure with large working angles to the craniocervical junction. The transcervical approach accesses the odontoid for resection from the body of C2 to the lip of the basion. The angles of attack in the transcervical approach when centered on the surgical target are limited, but this approach offers a clean, sterile operative field. Clinical investigation will be required to determine the optimal indications for each approach.
On the geometry of discrete exponential families with application to exponential random graph models

There has been an explosion of interest in statistical models for analyzing network data, and considerable interest in the class of exponential random graph (ERG) models, especially in connection with difficulties in computing maximum likelihood estimates. The issues associated with these difficulties relate to the broader structure of discrete exponential families. This paper re-examines the issues in two parts. First we consider the closure of k-dimensional exponential families of distribution with discrete base measure and polyhedral convex support P. We show that the normal fan of P is a geometric object that plays a fundamental role in deriving the statistical and geometric properties of the corresponding extended exponential families. We discuss its relevance to maximum likelihood estimation, both from a theoretical and computational standpoint. Second, we apply our results to the analysis of ERG models. By means of a detailed example, we provide some characterization of the properties of ERG models, and, in particular, of certain behaviors of ERG models known as degeneracy.
Warp-averaging event-related potentials

Abstract Objective : To align the repeated single trials of the event-related potential (ERP) in order to get an improved estimate of the ERP. Methods : A new implementation of the dynamic time warping is applied to compute a warp-average of the single trials. The trilinear modeling method is applied to filter the single trials prior to alignment. Alignment is based on normalized signals and their estimated derivatives. These features reduce the misalignment due to aligning the random alpha waves, explaining amplitude differences in latency differences, or the seemingly small amplitudes of some components. Results : Simulations and applications to visually evoked potentials show significant improvement over some commonly used methods. Conclusions : The new implementation of the dynamic time warping can be used to align the major components (P1, N1, P2, N2, P3) of the repeated single trials. The average of the aligned single trials is an improved estimate of the ERP. This could lead to more accurate results in subsequent analysis.
A collage of experimental investigations on smart fibrous composite structures and mechanical systems featuring electro-rheological fluids, piezoelectric materials and fiber-optic sensors

Abstract A collection of diverse experimental investigations is presented herein which demonstrates the active vibration-control capabilities of macroscopically smart fibrous composite structures featuring electro-rheological (ER) fluids, piezoelectric materials and fiber-optic sensing systems. This collage of investigations demonstrates the ability of beam- and plate-like structures fabricated in this class of smart laminated materials to tailor their elastodynamic characteristics in real-time. By judicious selection, the smart-materials designer can synthesize numerous classes of hybrid actuation systems from a variety of generic actuator systems in order to satisfy a broad range of performance specifications that cannot be satisfied by integrating only a single type of actuator system within this class of composite structures.
Backward Shift Invariant Operator Ranges

Results on first order Ext groups for Hilbert modules over the disk algebra are used to study certain backward shift invariant operator ranges, namely de Branges–Rovnyak spaces and a more general class called H(W; B) spaces. Necessary and sufficient conditions are given for the groups Ext1A(D)(H2C, H(W; B)) to vanish whereH2Cis thedualof the vector-valued Hardy module, H2C. One condition involves an extension problem for the Hankel operator with symbolB,ΓB, but viewed as a module map from H2Cinto H(W; B). The group Ext1A(D)(H2C, H(W; B))=(0) precisely whenΓBextends to a module map from L2Cinto H(W; B) and this in turn is equivalent to the injectivity of H(W; B) in the category of contractive HilbertA(D)-modules. This result applied to the de Branges–Rovnyak spaces yields a connection between the extension problem for the HankelΓB and the operator corona problem.
Percutaneous toxicity of pyridinethiones in a dimethylsulfoxide vehicle

The percutaneous toxicity of three salts of pyridinethione in water and dimethylsulfoxide is described. Sodium and zinc pyridinethione penetrated the skin of rabbits when applied in a dimethylsulfoxide vehicle and caused hind quarter paralysis. Cadmium pyridinethione did not penetrate the skin in amounts comparable to the other two salts regardless of the vehicle.