cssi/SciSciGPT-SciSciNet huggingface dataset:
Principal Component Networks: Parameter Reduction Early in Training.

Recent works show that overparameterized networks contain small subnetworks that exhibit comparable accuracy to the full model when trained in isolation. These results highlight the potential to reduce training costs of deep neural networks without sacrificing generalization performance. However, existing approaches for finding these small networks rely on expensive multi-round train-and-prune procedures and are non-practical for large data sets and models. In this paper, we show how to find small networks that exhibit the same performance as their overparameterized counterparts after only a few training epochs. We find that hidden layer activations in overparameterized networks exist primarily in subspaces smaller than the actual model width. Building on this observation, we use PCA to find a basis of high variance for layer inputs and represent layer weights using these directions. We eliminate all weights not relevant to the found PCA basis and term these network architectures Principal Component Networks. On CIFAR-10 and ImageNet, we show that PCNs train faster and use less energy than overparameterized models, without accuracy loss. We find that our transformation leads to networks with up to 23.8x fewer parameters, with equal or higher end-model accuracy---in some cases we observe improvements up to 3%. We also show that ResNet-20 PCNs outperform deep ResNet-110 networks while training faster.
Pericytes improve locomotor recovery after spinal cord injury in male and female neonatal rats

OBJECTIVE It is not known how activation of the hypoxia-inducible factor (HIF) pathway in pericytes, cells of the microvascular wall, influences new capillary growth. We tested the hypothesis that HIF-activated pericytes promote angiogenesis in a neonatal model of spinal cord injury (SCI). METHODS Human placental pericytes stimulated with cobalt chloride and naive pericytes were injected into the site of a thoracic hemi-section of the spinal cord in rat pups on postnatal day three (P3). Hindlimb motor recovery and Doppler blood flow perfusion at the site of transection were measured on P10. Immunohistochemistry was used to visualize vessel and neurofilament density for quantification. RESULTS Injection of HIF-activated pericytes resulted in greater vascular density in males but did not result in improved motor function for males or females. Injection of non-HIF-activated pericytes resulted improved motor function recovery in both sexes (males, 2.722 ± 0.31-fold score improvement; females, 3.824 ± 0.58-fold score improvement, P < .05) but produced no significant changes in vessel density. CONCLUSIONS HIF-activated pericytes promote vascular density in males post-SCI. Acute delivery of non-HIF-activated pericytes at the site of injury can improve motor recovery post-SCI.
Toward understanding solitary wave propagation in composite-cylinders-based 1D granular crystals

Abstract One-dimensional (1D) granular crystals are demonstrated to be outstanding nonlinear systems for supporting various types of novel stress waves. This letter reports on the investigation of solitary wave propagation within 1D granular crystals based on composite cylinders. We design two types of composite particles by creating a material mismatch within the granular, i.e., core–shell and sandwich types. We discover that such 1D composite granular chains support the formation of strongly nonlinear solitary waves. A finite element model is constructed to describe wave propagation behaviors fully validated by experiments. We conduct a theoretical analysis that agrees with numerical results and uncovers the physical mechanisms of solitary wave propagation in 1D composite granular chains through the parametric study. Finally, the fundamental understanding of dynamic responses is extended to more generalized composite granular chains with sandwich configurations. Results provide in-depth physical understanding and engineering design guidance to quantitatively tailor wave properties through simple 1D granular structures.
Performance of Impulse Response Testing on Prismatic Members with Intermediate Joints

Nondestructive Testing (NDT) methods have extensively been used to assess the conditions of civil infrastructure in the recent decades. Among various NDT techniques, Impulse Response (IR) has a vast application due to its simplicity and low cost. However, factors such as reflections from changes in impedance along the investigated members can adversely influence the success of the method. Numerous numerical and experimental studies have already been performed to evaluate the effect of change in mechanical impedances such as bulging, necking and similar anomalies. In this study, the effect of the presence of joints connecting the investigated members to other members, as another source of impedance change, is demonstrated. A three-story steel-concrete composite column of a building was selected for testing and IR tests were conducted. The obtained mobility graphs were clear, and the height of the column was easily measured with an acceptable error. The results of this study show that although the joints located between the top and bottom of the tested member are sources of change in mechanical impedance, they do not result in concealing the resonant frequencies from the wave reflected from the bottom of the member. Thus, IR method seems to be applicable in determining the length of prismatic members with intermediate joints such as piles of unknown bridge foundations with bracing and columns of buried buildings.
Junction Field-Effect Transistors

The junction field-effect transistor (JFET) was first analyzed by Shockley in 1952 (Shockley, 1952). Because its conduction process involves predominately one kind of carrier, the JFET is called a unipolar transistor to distinguish it from the bipolar transistor. Based on Shockley’s theoretical treatment, the first working JFET was reported by Dacey and Ross (1953). The junction field-effect transistor has several key features. First, it has no surface effects, such as interface traps occurring at the oxide—semiconductor interface. As a result, the noise level associated with the current fluctuation due to capture and release of free carriers at the surface effects is very low. Second, the isolated two gate terminals of a JFET allow two different input signals to be applied simultaneously for signal-mixing purposes. Third, the carrier transport in a JFET is made up predominantly of the majority carriers, and thus the switching speed of a JFET is not limited by the minority carrier charge storage such as that in a bipolar junction transistor. The main drawbacks of JFETs are that the structure is not compact and the JFET is a low-current-handling device and is thus not suitable for power amplification.
TMEM120 is a coenzyme A-binding membrane protein with structural similarities to ELOVL fatty acid elongase

Abstract TMEM120A, also named as TACAN, is a novel membrane protein highly conserved in vertebrates and was recently proposed to be a mechanosensitive channel involved in sensing mechanical pain. Here we present the single particle cryo-EM structure of human TMEM120A which forms a tightly packed dimer with extensive interactions mediate by the N-terminal coiled coil domain (CCD), the C-terminal transmembrane domain (TMD), and the re-entrant loop between the two domains. The TMD of each TMEM120A subunit contains six transmembrane helices (TMs) and has no clear structural feature of a channel protein. Instead, the six TMs form an α-barrel with a deep pocket where a coenzyme A (CoA) molecule is bound. Intriguingly, some structural features of TMEM120A resemble those of elongase for very long-chain fatty acid (ELOVL) despite low sequence homology between them, pointing to the possibility that TEME120A may function as an enzyme for fatty acid metabolism, rather than a mechanosensitive channel.
A Multivariate Interpretation of the Spanish-Language NIH Toolbox Cognition Battery: The Normal Frequency of Low Scores.

OBJECTIVE The current study involved the preparation of multivariate base rates for the Spanish-language NIH Toolbox Cognition Battery (NIHTB-CB) based on the U.S. normative sample, quantifying the normal frequency of low scores among healthy adults. METHOD Participants included 250 healthy Latinx adults (M = 38.8 ± 13.7 years old, range: 19-80; 72.0% women; education: M = 11.5 ± 3.9 years) who completed the full Spanish-language NIHTB-CB, including two tests of crystallized cognition and five tests of fluid cognition. Multivariate base rates quantified the frequency at which participants obtained 1 or more fluid scores ≤25th, ≤16th, ≤9th, ≤5th, and ≤2nd percentile, per age-adjusted or demographically adjusted (age, gender, education) normed scores. RESULTS A substantial minority of participants had 1 or more low scores (e.g., 40.4% had 1 or more age-adjusted score ≤16th percentile). The frequencies of low scores increased with fewer years of education and lower crystallized cognitive ability. Higher frequencies of low scores were observed among participants who were born and educated abroad, versus within the USA; monolingual Spanish speakers, versus bilingual Spanish/English speakers; and from households below the national median income, versus households above the national median. CONCLUSION Low scores were common and related to crystallized ability, education, and sociocultural variables. Although using demographically adjusted scores reduced group differences related to sociocultural variables, group differences were not eliminated, indicating that age, gender, and education score adjustments do not fully explain the associations between sociocultural variables and test performances. These stratified base rates may be useful when working with Spanish-speaking patients with diverse sociocultural characteristics.
Correlated population genetic structure in a three-tiered host-parasite system. The potential for coevolution and adaptive divergence.

Three subspecies of Northern Bahamian Rock Iguanas, Cyclura cychlura, are currently recognized: C. c. cychlura, restricted to Andros Island, and C. c. figginsi and C. c. inornata, native to the Exuma Island chain. Populations on Andros are genetically distinct from Exuma Island populations, yet genetic divergence among populations in the Exumas is inconsistent with the two currently recognized subspecies from those islands. The potential consequences of this discrepancy might include the recognition of a single subspecies throughout the Exumas rather than two. That inference also ignores evidence that populations of C. cychlura are potentially adaptively divergent. We compared patterns of population relatedness in a three-tiered host-parasite system: C. cychlura iguanas, their ticks (genus Amblyomma, preferentially parasitizing these reptiles), and Rickettsia spp. endosymbionts (within tick ectoparasites). Our results indicate that while C. c. cychlura on Andros is consistently supported as a separate clade, patterns of relatedness among populations of C. c. figginsi and C. c. inornata within the Exuma Island chain are more complex. The distribution of the hosts, different tick species, and Rickettsia spp., supports the evolutionary independence of C. c. inornata. Further, these patterns are also consistent with two independent evolutionarily significant units within C. c. figginsi. Our findings suggest coevolutionary relationships between the reptile hosts, their ectoparasites, and rickettsial organisms, suggesting local adaptation. This work also speaks to the limitations of using neutral molecular markers from a single focal taxon as the sole currency for recognizing evolutionary novelty in populations of endangered species.
Multi-scale dynamics of heterochromatin repair

Studies across different organisms show that nuclear architecture and dynamics play central roles in different aspects of homologous recombination (HR) repair. Here we review the most recent discoveries in this field, ranging from directed motions mediating relocalization pathways, to global chromatin mobilization, local DNA looping, and changes in repair focus properties associated with clustering and phase separation. We discuss how these dynamics work in different contexts, including molecular mechanisms and regulatory pathways involved. We specifically highlight how they function in pericentromeric heterochromatin, which presents a unique environment for HR repair given the abundance of repeated DNA sequences prone to aberrant recombination, the 'silent' chromatin state, and the phase separation characterizing this domain.
Gaussian process model selection for parameter estimation in ocean acoustics

The dynamic nature of the ocean environment presents numerous challenges to parameter estimation in ocean acoustics. We present a variational Bayesian method which selects an optimal model for parameter estimation in ocean acoustics using Gaussian process (GP) regression. GP model selection is based on Bayesian model selection, which treats the parameters and kernel selection of the model as hyperparameters and uses Bayesian inference to compute a model’s likelihood with respect to its hyperparameters. However, in Bayesian model selection, the integrals over parameter space are often intractable and require approximation or sampling methods such as Markov chain Monte Carlo. GP renders these integrals tractable by treating hyperparameters as multivariate Gaussian distributions, which greatly speeds up the optimization. Furthermore, model selection using GPs allows for straightforward evaluation of uncertainty in the selected model’s likelihood. In this study, we compare results of acoustic parameter estimation from Bayesian and GP model selection using an ocean acoustic propagation model.
Tissue Bioavailability of Tart Cherry Anthocyanins

The therapeutic effects of tart cherry anthocyanins cannot be understood without analysis of their tissue distribution,metabolism, and excretion. The definition of bioavailability simply refers to the proportion of known compound that is absorbed and metabolised in an organism. Tissue uptake of anthocyanins may depend on their chemical structure, as influenced by the nature of the attached sugar moiety, and also, by the structure of the aglycone. The parent phytochemicals contain functional groups (e.g., a hydroxyl group) that often undergo conjugation reactions with endogenous compounds to yield more polar and water-soluble compounds. The latter are usually ideal substrates for active transport out of cells, tissues, and organs with eventual excretion from the body. The sugar conjugates of anthocyanins may also have an effect on the bioavailability of bioactive phytochemicals. Consequently, it is not only important to know how much of a bioactive metabolite is present in tart cherry; but it is even more ...
Quantitative Analysis of Petroleum Oil Pollutants by Infrared Spectrophotometry

The accuracy and sensitivity of infrared spectrophotometry are evaluated for the quantitative analysis of water dispersed oils, by single point analysis. Absorbance versus concentration (Beer-Bouguer Law) plots are prepared for viscous and nonviscous crude and processed oils in Freon 113, carbon tetrachloride, and in a mixture of these solvents. Absorbances at 2930/cm are measured in 10 and 100-mm path length cells, with and without ordinate scale expansion. Solution concentrations in the range 0.5 to 40 mg/100 ml oil in solvent yield linear plots that pass through the origin. The concentration 0.05 mg/100 ml oil in solvent yields a recognizable absorption band at approximately 2930/cm when measured in 100-mm path length cells with ordinate scale expansion x5. This is considered the practical detection limit of these oils by the infrared (IR) technique. Stability of oil absorptivities following solution storage, and use of IR absorptivities for oil identification are also examined briefly.
Abstract #4412: GUCY2C establishes lineage dependence in intestinal tumorigenesis through AKT

An evolving paradigm expanding the genetic basis of cancer suggests that tissue-specific developmental programs indelibly imprint restricted repertoires of homeostasis, forming the substrate for lineage-dependent tumor induction by dysregulation of survival pathways. GUCY2C, the intestinal receptor for the paracrine hormones guanylin and uroguanylin whose early loss universally characterizes colorectal transformation, has emerged as a component of homeostatic programs organizing spatiotemporal patterning along the crypt-surface axis, and its dysregulation promotes tumorigenesis through hyperproliferation and genetic instability. Here we identify GUCY2C as a switch for lineage-dependent tumorigenesis whose disruption reprograms survival circuits essential for regenerative homeostasis and universally required for tumorigenesis. Eliminating GUCY2C expression in mice expands proliferating crypts, accelerating the cell cycle by regulating mediators of the G1/S transition, including cyclin D1, pRb, and p27. Further, loss of GUCY2C produces an increase in aerobic glycolysis, reflected by elevated glucose transport and lactate production associated with increased expression of rate-limiting glycolytic proteins universally up-regulated in tumors, including glucose transporter I, hexokinase II, phosphofructokinase, and pyruvate kinase. Conversely, there is a reciprocal reduction in mitochondrial biogenesis and oxidative phosphorylation, reflected by a decrease in mitochondrial genome, proteins, and organelles associated with reduced mitochondrial oxygen consumption, dehydrogenase activity and ATP production, recapitulating the tumor metabolic phenotype. Conversely, GUCY2C signaling restores replicative and metabolic homeostatic circuits in colon cancer cells, recapitulating the phenotype of normal enterocytes. Moreover, oral administration of the proximal downstream mediator of GUCY2C, cyclic GMP, reverses crypt hyperplasia and restores proliferative and metabolic programs in mice deficient in GUCY2C. Coordination of survival circuits by GUCY2C is orchestrated through the oncogene AKT, whose inhibition mimics, and activation eliminates, GUCY2C regulation of proliferation and metabolism. AKT modulation by GUCY2C involves the tumor suppressor PTEN, whose silencing eliminates GUCY2C regulation of AKT, proliferation and metabolism. Thus, disruption of developmentally restricted signaling by GUCY2C, reflecting loss of paracrine hormones, induces maladaptive survival pathways essential for crypt-surface homeostasis whose tissue-specific deregulation contributes to lineage dependency in intestinal tumorigenesis. With the role of guanylin and uroguanylin loss in transformation, the universal compensatory over-expression of GUCY2C by colorectal tumors offers a unique therapeutic opportunity for cancer prevention through oral hormone supplementation. Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 4412.
Indigenous Theology: Sources and Resources Perspectives from the Philippines

This article proposes an approach to doing theology with and for the indigenous communities in the Philippines, specifically the Ygollotes/Igorots of the Cordillera region, in their struggle for identity and self-determination. It proceeds from a protest ritual that is representative and celebrative of the culture and identity; the religious and spiritual resources; the emancipatory stories; the vision, hopes and struggles of these northern Philippines indigenous communities. The article focuses on rereading the land-centred culture, spirituality, and life of indigenous communities in the context of their struggles for fullness of life, with the perspective of identifying several sources and resources for a liberative, ecumenical, and indigenous peoples' theology of struggle.
Magnetic moments of Δ++ and from QCD sum rules

Abstract QCD sum rules for the magnetic moments of Δ++ and Ω − are derived using the external field method. They are analyzed by a Monte Carlo based procedure, using realistic estimates of the QCD input parameters. The results are consistent with the measured values, despite relatively large errors that can be attributed mostly to the poorly-known vacuum susceptibility χ. It is shown that a 30% level accuracy can be achieved in the derived sum rules, provided the QCD input parameters are improved to the 10% level.
Plants, Seeds, Roots, and Soils as Applications of Magnetic Resonance Microscopy

High-resolution magnetic resonance microscopy is discussed as a useful tool in the study of plant structure and physiology. In contrast to animals, plants have a relatively homogenous distribution of water throughout the tissues. High quality images highlighting both structural and physiological differences can be acquired of plant specimens, however, based on traditional MR parameters of T1, T2 and susceptibility effects from air filled spaces. Typical in plane resolutions of 5–40 µm3 can be acquired, showing significant contrasts between tissues. Additionally, MR microscopy offers the ability to visualize and study plant roots in situ, without removal from the soil substrate. Applications of MR microscopy to plants includes studies of developmental anatomy, physiological changes with maturation, environmental physiology, pathologies, and the study of intact roots in soil. Keywords: MRI; magnetic resonance imaging; fruit; stems; plant disease; water transport; sap flow
A multivariate analysis of risk factors for cytomegalovirus infection in liver-transplant recipients.

Thirty-three consecutive liver-transplant recipients were prospectively studied over a 37-mo period for evidence of cytomegalovirus infection. Sixteen (48%) episodes of cytomegalovirus infection were identified; 9 were primary infections and 7 were recurrent infections. Beginning with patient 8, γ-globulin prophylaxis was routinely administered to most patients. Twelve potential risk factors for cytomegalovirus infection were evaluated and included pretransplant cytomegalovirus serological status of donor and recipient; recipient's age, sex, race, and liver disease; number and type of blood products transfused; type and intensity of immunosuppression; and occurrence of rejection. The Cox proportional hazards model identified positive donor cytomegalovirus serology as the single most important risk factor for subsequent development of cytomegalovirus infection, regardless of recipient cytomegalovirus serological status. In addition, use of γ-globulin prophylaxis seemed to be protective against the occurrence of disseminated cytomegalovirus disease.
The Early Years of Native American Art History: The Politics of Scholarship and Collecting

The Early Years of Native American Art History: The Politics of Scholarship and Collecting. Edited by Janet Catherine Berlo. Seattle: University of Washington Press, 1992. 244 pp., 39 b/w Illustrations. $30.00 (cloth).
Nutrient Loadings to Streams of the Continental United States from Municipal and Industrial Effluent.

Maupin, Molly A. and Tamara Ivahnenko, 2011. Nutrient Loadings to Streams of the Continental United States From Municipal and Industrial Effluent. Journal of the American Water Resources Association (JAWRA) 47(5):950-964. DOI: 10.1111/j.1752-1688.2011.00576.x Abstract: Data from the United States Environmental Protection Agency Permit Compliance System national database were used to calculate annual total nitrogen (TN) and total phosphorus (TP) loads to surface waters from municipal and industrial facilities in six major regions of the United States for 1992, 1997, and 2002. Concentration and effluent flow data were examined for approximately 118,250 facilities in 45 states and the District of Columbia. Inconsistent and incomplete discharge locations, effluent flows, and effluent nutrient concentrations limited the use of these data for calculating nutrient loads. More concentrations were reported for major facilities, those discharging more than 1 million gallons per day, than for minor facilities, and more concentrations were reported for TP than for TN. Analytical methods to check and improve the quality of the Permit Compliance System data were used. Annual loads were calculated using “typical pollutant concentrations” to supplement missing concentrations based on the type and size of facilities. Annual nutrient loads for over 26,600 facilities were calculated for at least one of the three years. Sewage systems represented 74% of all TN loads and 58% of all TP loads. This work represents an initial set of data to develop a comprehensive and consistent national database of point-source nutrient loads. These loads can be used to inform a wide range of water-quality management, watershed modeling, and research efforts at multiple scales.
Scatter correction for gamma cameras using constrained deconvolution

Several groups have proposed the use of multiwindow (usually dual window) techniques for scatter correction in SPECT (single photon emission computed tomography) and conventional gamma camera imaging. The authors have developed a technique for constrained deconvolution of the primary photopeak from the observed spectrum using multiple (5-30) windows. They have tested it both with simulations and with a modified gamma camera capable of recording x, y, and E information inlist mode, which enables postprocessing of the data for scatter correction. >
Pedro Zamora and Pedro and Me in Requiem: Scoring the Loss

When originally published at the turn of the century, Pedro and Me: Friendship, Loss, and What I Learned (2000) was riding both the popularity of its reality television roots and the growing awareness of homosexuality in the popular consciousness. At that time, too, Macmillan publisher Henry Holt had its own website set up to support Winick’s work; it featured interviews, tour dates, and, most importantly, omitted scenes originally drafted but not completed by the author. The opportunity to finally include this apocrypha was missed in the newer 2009 addition, as the publisher opted for a one-page afterword. This paper discusses how this constitutes a missed opportunity to reconnect with Pedro. In as much as the original graphic novel—or any graphic novel—is a construction, the tenth anniversary edition of Pedro and Me disallowed the excluded raw material from being included in audience’s score-overdue deconstruction of the work.
Evaluating spawning migration patterns and predicting spawning success of shovelnose sturgeon in the Lower Missouri River

Summary Approaches using telemetry, precise reproductive assessments, and surgically implanted data storage tags (DSTs) were used in combination with novel applications of analytical techniques for fish movement studies to describe patterns in migratory behavior and predict spawning success of gravid shovelnose sturgeon. From 2004 to 2007, over 300 gravid female shovelnose sturgeon (Scaphirhynchus platorynchus) from the Lower Missouri River, that were expected to spawn in the year they were collected, were surgically implanted with transmitters and archival DSTs. Functional cluster modeling of telemetry data from the spawning season suggested two common migration patterns of gravid female shovelnose sturgeon. Fish implanted from 958 to 1181 river kilometer (rkm) from the mouth of the Missouri River (or northern portion of the Lower Missouri River within 354 rkm of the lowest Missouri River dam at rkm 1305) had one migration pattern. Of fish implanted from 209 to 402 rkm from the mouth of the Missouri River (or southern portion of the Lower Missouri River), half demonstrated a movement pattern similar to the northern fish while the other half demonstrated a migration pattern that covered more of the river. There was no apparent difference in migration patterns between successful and unsuccessful spawners. Multiple hypotheses exist to explain differences in migratory patterns among fish from different river reaches. Additional work is required to determine if observed differences are due to multiple adapted strategies, environmental alteration, and/or initial tagging date. Hierarchical Bayesian modeling of DST data indicated that variation in depth usage patterns was consistently different between successful and unsuccessful spawners, as indicated by differences in likelihood of switching between high and low variability states. Analyses of DST data, and data collected at capture, were sufficient to predict 8 of 10 non-spawners/incomplete spawners and all 30 spawners in the absence of telemetry location data. Together, the results of these two separate analyses suggest that caution is necessary in extrapolating spawning success from broad-scale movement data alone. More direct measures of spawning success may be necessary to precisely determine spawning success and to evaluate the effects of management actions.
Community Organizing and Community Building for Health and Welfare, by Minkler, M. (Ed.)

In the third edition of her popular book, Meredith “Merry” Minkler builds upon her scholarship and authority on community organizing and community building with application to current issues in the...
Effects of mistuning on bending-torsion flutter and response of a cascade in incompressible flow

The effect of small differences between the individual blades (mistuning) on the aeroelastic stability and response of a cascade were studied. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade and the aerodynamic coupling between the blades was considered. A digital computer program was developed to conduct parametric studies. Results indicate that the mistuning has a beneficial effect on the coupled bending torsion and uncoupled torsion flutter. On forced response, however, the effect may be either beneficial or adverse, depending on the engine order of the forcing function. The results also illustrate that it may be feasible to utilize mistuning as a passive control to increase flutter speed while maintaining forced response at an acceptable level.
A Putative Metabolite of Serotonin, Tryptamine-4,5-Dione, Is an Irreversible Inhibitor of Tryptophan Hydroxylase: Possible Relevance to the Serotonergic Neurotoxicity of Methamphetamine

Tryptamine-4,5-dione (T-4,5-D) is formed as a result of oxidation of 5-hydroxytryptamine by superoxide (O(2)(-)(*), nitric oxide (NO*), and peroxynitrite (ONOO(-)). T-4,5-D rapidly inactivates tryptophan hydroxylase (TPH), derived from rat brain, probably as a result of covalent modification of active site cysteine residues. The activity of TPH exposed to T-4,5-D cannot be restored by anaerobic reduction with dithiothreitol (DTT) and ferrous iron (Fe(2+)) indicating that the inactivation is irreversible. 7-S-Glutathionyl-tryptamine-4,5-dione, formed by the rapid reaction between T-4,5-D and glutathione, also inhibits TPH but in this case the activity is restored by anaerobic reduction with DTT/Fe(2+). The results of this investigation may be relevant to the initial reversible and subsequent irreversible inactivation of TPH evoked by methamphetamine and 3,4-methylenedioxymethamphetamine.
Thermodynamics of the interactions of lac repressor with variants of the symmetric lac operator: effects of converting a consensus site to a non-specific site.

What are the thermodynamic consequences of the stepwise conversion of a highly specific (consensus) protein-DNA interface to one that is nonspecific? How do the magnitudes of key favorable contributions to complex stability (burial of hydrophobic surfaces and reduction of DNA phosphate charge density) change as the DNA sequence of the specific site is detuned? To address these questions we investigated the binding of lac repressor (LacI) to a series of 40 bp fragments carrying symmetric (consensus) and variant operator sequences over a range of temperatures and salt concentrations. Variant DNA sites contained symmetrical single and double base-pair substitutions at positions 4 and/or 5 [sequence: see text] in each 10 bp half site of the symmetric lac operator (Osym). Non-specific interactions were examined using a 40 bp non-operator DNA fragment. Disruption of the consensus interface by a single symmetrical substitution reduces the observed equilibrium association constant (K(obs)) for Osym by three to four orders of magnitude; double symmetrical substitutions approach the six orders in magnitude difference between specific and non-specific binding to a 40 bp fragment. At these adjacent positions in the consensus site, the free energy effects of multiple substitutions are non-additive: the first reduces /deltaG(obs)o/ by 3 to 5 kcal mol(-1), approximately halfway to the non-specific level, whereas the second is less deleterious, reducing /deltaG(obs)o/ by less than 3 kcal mol(-1). Variant-specific dependences of K(obs) on temperature and salt concentration characterize these LacI-operator interactions. In general, binding constants and standard free energies of binding both exhibit characteristic extrema near 290 K. As a consequence, both the enthalpic and entropic contributions to stability of Osym and variant complexes change from positive (i.e. entropy driven) at lower temperatures to negative (i.e. enthalpy driven) at higher temperatures, indicating that the heat capacity change upon binding, deltaC(obs)o, is large and negative. In general, /deltaC(obs)o/ decreases as the specificity and stability of the variant complex decreases. Stabilities of complexes of LacI with Osym and all variant operators are strongly [salt]-dependent. Binding constants for the variant complexes exhibit a power-dependence on [salt] that is larger in magnitude (i.e. more negative) than for Osym, but no obvious trend relates changes in contributions from the polyelectrolyte effect and the observed reductions in stability (delta deltaG(obs)o). These variant-specific thermodynamic signatures provide novel insights into the consequences of converting a consensus interface to a less specific one; such insights are not obtained from comparisons at the level of delta deltaG(obs)o. We propose that this variant-specific behavior arises from a strong effect of operator sequence on the extent of induced conformational changes in the protein (and possibly also in the DNA site) which accompany binding.
Studies on the specificity of thyroid response to pituitary glycoprotein hormones

Abstract Thyrotropins (TSH) and gonadotropins (luteinizing hormone, LH, and follicle-stimulating hormone, FSH) purified from ovine, bovine, ostrich, sea turtle, and bullfrog pituitary glands were tested for their ability to simulate the thyroid glands of four species of amphibians (three anurans and a urodele), a reptile (the slider turtle), and a bird (the cockerel). All animals tested responded specifically to mammalian, sea turtle, and ostrich thyrotropins; any thyroid-stimulating activity of the gonadotropins from these species could be accounted for by their contamination with thyrotropin. In addition, the three anuran species showed a high degree of specificity for bullfrog TSH; bullfrog LH exhibited low thyrotropic activity in amphibians. In contrast, bullfrog LH was more potent than bullfrog TSH in stimulating the thyroid gland of the cockerel. This bird therefore resembles reptiles in showing a “heterothyrotropic” response to bullfrog LH. The hormonal specificity of thyroid response to these pituitary glycoprotein hormones therefore varies distinctly among representatives of different vertebrate classes. Although the tetrapods tested were generally specific for thyrotropin in their thyroid responses to homologous and heterologous pituitary hormones, occasionally a lack of specificity for heterologous hormones existed which could be shared by species from closely-related classes. The varied patterns seen indicate that independent evolution of the functional characteristics of the thryotropin receptor has occurred to different degrees within each vertebrate class.
Scent Marking by Males of the Mediterranean Fruit Fly, Ceratitis capitata (Diptera: Tephritidae)

Males of the Mediterranean fruit fly, Ceratitis capitata (medfly), defend individual leaves as mating territories. While perching, males release an air-borne pheromone (known to attract females) from everted rectal epithelium at the tip of the abdomen. Males also occasionally touch the substrate with the tip of their abdomen. The main objective of the present study was to determine whether such abdomen dipping was a form of intersexual signaling, i.e., whether this action resulted in increased female visitation to the territory. Following observations on the frequency of pheromone calling and abdomen dipping of individually marked males, I ran a standard set of experiments using leaves from four different plant species. Leaves were exposed to varying numbers of (mature) males and females, respectively, for varying durations, and female settlement was compared on exposed versus nonexposed leaves in laboratory cages. Exposing leaves to females had no, or little, influence on female distribution for any of the four plant species. Exposing leaves to males had little influence on subsequent female settlement for orange, coffee, or macadamia trees. However, leaves of the fig tree Ficus bejamina that were exposed to males were much more attractive to females than nonexposed leaves. I then conducted a series of additional tests using fig leaves and found that i) leaf exposure to immature males had no effect on female distribution, ii) leaf exposure to mature males for as little as 90 min increased leaf attractiveness to females, iii) prohibiting males direct contact with the leaf during exposure eliminated any effect on female settlement, and iv) females discriminated between exposed and nonexposed leaves even in physically complex environments (i.e., potted plants). The possible role of abdomen dipping in sexual advertisement of male medflies is discussed.
Properties of polymers after cryogenic neutron irradiation

Abstract Organic matrix insulation has been specified for use in fusion reactor superconducting coils due to lower material and fabrication costs compared to other forms of insulation. Glass fabric filled resins are prime candidates since they provide not only electrical insulation, but also the mechanical strength necessary to withstand the high magnetic forces present during coil operation. Two epoxy- and two polyimide-based fiber reinforced materials were irradiated to neutron fluences of 4.1 × 10 21 n/m 2 , E > 0.1 MeV at 4.2 K. Post-irradiation testing included flexural (3 pt. bend), as well as DC conductivity and dielectric breakdown strength. Measurements were made at 77 K and 300 K. Flexural strength was observed to decrease for the epoxy-based materials while the polyimide-based materials exhibited essentially no change in strength. Both DC conductivity and dielectric breakdown strength revealed little or no pattern of degradation at all levels of radiation exposure.
Reassessing the role of astrocytes in ammonia neurotoxicity

High blood ammonia, as seen in severe liver disease and urea cycle disorders, is neurotoxic and difficult to treat. A new study shows that the toxic effects are caused by impaired astrocyte potassium buffering—not astrocyte swelling, as previously thought—and can be partially blocked by the diuretic bumetanide (pages 1643–1648).
Intraoperative hypotension due to unrecognized bleeding from a continuous spinal catheter site

We recently cared for a patient who had a rare complication from a continuous spinal catheter: extensive bleeding around the catheter insertion site. This complication went unrecognized intraoperatively because the bleeding was hidden from view. The possible etiologies for this bleeding are discussed, as well as methods to recognize this complication before significant bleeding occurs.
Chemical composition and effects of water extracts of petroleum on eggs of the sand dollar Melitta quinquiesperforata

Sperm and eggs of sand dollars, Melitta quinquiesperforata (Leske), were subjected to two petroleum oils, and effects determined. The oils chosen were Kuwait crude and No. 2 fuel oil, supplied by the American Petroleum Institute. Water-soluble extracts (WSF) from oil-sea water mixes were prepared and the major aromatic components in the WSF of the fuel oil were identified. WSF of No. 2 fuel oil depressed respiration, mobility of sperm, interfered with fertilization and cleavage, and retarded larval development. The effects were detectable at dilutions of 4% and less (about 0.6 ppm of WSF). Kuwait crude was much less toxic. There was no effect on water permeability of the egg membrane. Results are compared with similar studies on other marine organisms.
A sodium-dependent sugar co-transport system in bacteria.

Summary A characteristics difference between active transport systems in bacterial and animal cells is that the latter usually require sodium ions and operate by the process of co-transport. The melibiose permease system (TMG permease II) of Salmonella typhimurium has now been identified as a sodium-dependent co-transport system. Co-transport, and the analogous mechanism, counter-transport, may be the underlying mechanisms for the active transport of many solutes by bacterial cells, although they may be difficult to detect.
Secretion of hepatic and intestinal alkaline phosphatases: similarities and differences.

The presence of plasma membrane-bound proteins in the serum of mammals has been noted for many years. Examples of such proteins include alkaline phosphatase (liver, bone, intestinal, and placental) [l], 5’-nucleotidase [2], and gamma-glutamyl transferase [3]. The mechanism of attachment of these proteins to the membrane is now fairly clear. Some proteins, e.g. gamma-glutamyl transferase, are attached to the plasma membrane by a hydrophobic transmembrane sequence [4]. Other proteins, including the alkaline phosphatases (AP), are bound by the fatty acid portion of a phosphatidylinositol-glycan anchor [5]. In spite of this information the mechanism for release of these enzymes from the membrane is not known. Moreover, because secretion is stimulated by factors unique to each organ, the mechanism(s) may differ from organ to organ, e.g. liver and intestine. A variety of suggestions have been offered to explain enzyme release, including detergent action, proteolysis, membrane fragmentation [6], or lipolysis [5]. Detergent action has been suggested most often for hepatocyte membrane proteins, because high concentrations of bile salts are present [7]. Normally the sinusoidal and canalicular alkaline phosphatases are secreted into the blood and bile respectively [S]. The enzyme in bile appears to be particulate [9], whereas that in the blood is largely soluble. The original interpretation of these data were that the sinusoidal enzyme was released by detergent action. However, recent work has shown that solublization with butanol was due not to detergent-like action, but to the activation of tissue phospholipase C that released fatty acids from the AP [lo]. Proteins attached to the membrane by a transmembrane segment could be released by the action of proteases in the membrane or in the surrounding fluid. Cell
Obesity Paradox in Amputation Risk Among Nonelderly Diabetic Men

The association between BMI and amputation risk is not currently well known. We used data for a cohort of diabetic patients treated in the US Department of Veterans Affairs Healthcare System in 2003. Men aged 40 kg/m2. The association between obesity and amputation risk in our data shows a pattern consistent with “obesity paradox” observed in many health conditions. More research is needed to better understand pathophysiological mechanisms that may explain the paradoxical association between obesity and lower-extremity amputation (LEA) risk.
Kin recognition in the sweat bee, Lasioglossum zephyrum.

Recognition of kin in sweat bees is dependent upon social learning. Shortly after emergence as adults, bees learn the odors of nestmates, normally relatives, and use this knowledge to keep nonnestmate (and therefore nonkin) bees out. The odors are heritable so that once a bee learns the odors of its kin, it can recognize other kin that it has never met before. An individual guard bee does not seem to use knowledge of self as a reference. Larval learning of odors, common rearing of offspring, maternal inheritance, and inbreeding effects are not sufficient to explain the recognition of unfamiliar relatives. Individual guard bees can discriminate between close and distant relatives. Kin recognition may be a secondary or serendipitous use of odors that originally evolved for the recognition of mates and nest entrances.
Macromolecular drug absorption in the albino rabbit eye

Abstract Proteins as well as polymers used in topical ophthalmic preparations are generally assumed to be excluded from the interior of the eye. Nonetheless, the corneal penetration of such high molecular weight compounds is of interest from both the drug toxicity and drug delivery points of view. The objective of this study was to determine, in a qualitative way, the mechanisms by which inulin permeated the cornea following topical dosing in the albino rabbit eye. Despite its molecular size (M.W. 5,000) and low n -octanol/buffer partition coefficient (1.27 × 10 −3 ), inulin was absorbed across the cornea. At 30 min post-dosing the amount of inulin recovered in the aqueous humor and anterior segment tissues of the eye was 0.12–0.37% of the topically applied dose. Results in this study suggest that the mechanism of corneal absorption of inulin is different from glucose and epinephrine. However, there is no evidence that a carrier or endocytosis is involved. It is suggested that further experiments are necessary to investigate the contribution of the paracellular pathway to the corneal absorption of inulin.
Trade Cumulus Cloud Groups: Some Observations Suggesting a Mechanism of Their Origin

On a recent field trip to the western Caribbean, temperature gradients in the surface layers of the trade-wind oceans were found and related to the presence of cumulus cloud groups. The cloud groups generally formed over and slightly downwind of warm spots which were several kilometers in extent along the wind and 0.1—0.3° C in amplitude. Clouds were not found in the absence of warm spots although warm spots were occasionally encountered without clouds. Air circulations, similar to but weaker than those pro***duced by heated land masses, are hypothesized to exist over oceanic warm spots and their magnitude is estimated from previous work on heated islands. Observed differences in low-level moisture structure between clear and cloudy areas may be interpreted in terms of such circulations and their evolution with time. Some suggestions are made concerning the life cycles of trade cumuli. DOI: 10.1111/j.2153-3490.1957.tb01851.x
Communications: Comparison of Two Samplers Used with an Automated Data Acquisition System in Whole-Pond, Community Metabolism Studies

Abstract Automated data-logging equipment permits frequent in situ measurements of water quality variables and allows for better estimates of primary production and community metabolism in aquaculture ponds. A system to sample four contiguous 0.1-hectare earthen ponds is described. Two samplers for obtaining water samples for analysis were designed and compared. The first sampled at discrete depths throughout the water column, whereas the second obtained a composite water column sample. Samplers were constructed from readily available stocks of iron accessories or polyvinyl chloride fittings. Mean dissolved oxygen concentration, pH, and temperature did not differ significantly between water samples taken by the two samplers.