cssi/SciSciGPT-SciSciNet huggingface dataset:
A WARNING: AN EPIDEMIC OF BABY POWDER ASPIRATION

Recently a pediatrician brought to the attention of the Nassau County Medical Center Poison Control Center his concern over baby powder aspiration. He had just encountered his second case in two months; one of these required hospitalization. Upon reviewing our Poison Control Center Logs we were astounded to discover 40 calls to our center during the past six months (Jan 1, 1980 to June 30, 1980), or approximately one of every 100 calls for children under the age of 5 years involved potential powder aspiration. Nine of these calls originated from emergency rooms, five from physicians9 offices, and 26 from mothers at home. We are presently doing a retrospective and prospective analysis of these calls. However, we do feel that this hazard represents a sufficient threat to children of fatal aspiration of powder that the pediatricians responsible for their care be notified without waiting for the results of our study. The Consumer Product Safety Commission has also been notified of this hazard. Baby powder is not considered harmful by most parents. Physicians caring for children should emphasize to parents that powders are not considered essential to the routine skin care of infants, but if powders are purchased, they should be stored out of reach of children because of their potential hazard. Some powder containers have the appearance of a baby bottle and may be mistakenly used in such a manner.
HLTF’s Ancient HIRAN Domain Binds 3′-DNA Ends to Drive Replication Fork Reversal

Stalled replication forks are a critical problem for the cell because they can lead to complex genome rearrangements that underlie cell death and disease. Processes such as DNA damage tolerance and replication fork reversal protect stalled forks from these events. A central mediator of these DNA damage responses in humans is the Rad5-related DNA translocase, HLTF. Here, we present biochemical and structural evidence that the HIRAN domain, an ancient and conserved domain found in HLTF and other DNA processing proteins, is a modified oligonucleotide/oligosaccharide (OB) fold that binds to 3' ssDNA ends. We demonstrate that the HIRAN domain promotes HLTF-dependent fork reversal in vitro through its interaction with 3' ssDNA ends found at forks. Finally, we show that HLTF restrains replication fork progression in cells in a HIRAN-dependent manner. These findings establish a mechanism of HLTF-mediated fork reversal and provide insight into the requirement for distinct fork remodeling activities in the cell.
A Review of “The Reviewer's Guide to Quantitative Methods in the Social Sciences”

Editors Hancock and Mueller dedicate their book to “the unheralded reviewers whose words frustrate and challenge us—and make our work stronger for it.” They are modest in their dedication as the au...
Yucca aloifolia (Asparagaceae) opts out of an obligate pollination mutualism1

UNLABELLED • PREMISE OF THE STUDY According to Cope's 'law of the unspecialized' highly dependent species interactions are 'evolutionary dead ends,' prone to extinction because reversion to more generalist interactions is thought to be unlikely. Cases of extreme specialization, such as those seen between obligate mutualists, are cast as evolutionarily inescapable, inevitably leading to extinction rather than diversification of participating species. The pollination mutualism between Yucca plants and yucca moths (Tegeticula and Parategeticula) would seem to be locked into such an obligate mutualism. Yucca aloifolia populations, however, can produce large numbers of fruit lacking moth oviposition scars. Here, we investigate the pollination ecology of Y. aloifolia, in search of the non-moth pollination of a Yucca species.• METHODS We perform pollinator exclusion studies on Yucca aloifolia and a sympatric yucca species, Y. filamentosa. We then perform postvisit exclusion treatments, an analysis of dissected fruits, and a fluorescent dye transfer experiment.• KEY RESULTS As expected, Yucca filamentosa plants set fruit only when inflorescences were exposed to crepuscular and nocturnal pollinating yucca moths. In contrast, good fruit set was observed when pollinators were excluded from Y. aloifolia inflorescences from dusk to dawn, and no fruit set was observed when pollinators were excluded during the day. Follow up experiments indicated that European honeybees (Apis mellifera) were passively yet effectively pollinating Y. aloifolia flowers.• CONCLUSIONS These results indicate that even highly specialized mutualisms may not be entirely obligate interactions or evolutionary dead ends.
Effects of ozone exposure on lipid metabolism in human alveolar macrophages.

Abstract Alveolar macrophages (AM) store arachidonic acid (AA), which is esterified in cellular phospholipids until liberated by phospholipase A2 or C after exposure to inflammatory stimuli. After release, there can be subsequent metabolism of AA into various potent, biologically active mediators including prostaglandins and platelet-activating factor (PAF). To examine the possibility that these mediators may account for some of the pathophysiologic alterations seen in the lung after ozone (O3) exposure, human AM were collected by bronchoalveolar lavage of normal subjects, plated into tissue culture dishes, and the adherent cells were incubated with [3H]AA or [3H]lysoPAF. Human AM exposed to 1.0 ppm O3 for 2 hr released 65 +/- 12% more tritium, derived from [3H]AA, than paired, air-exposed controls into media supernatants. In other studies using a similar O3 exposure protocol, there was also a significant increase in human AM prostaglandin E2 production (2.0 +/- 0.5-fold increase above air-exposure values, p less than 0.01, n = 17). In additional studies, using a similar O3 exposure protocol (1.0 ppm for 1 hr), there was also a significant increase in human AM PAF content (1.7 +/- 0.2-fold increase above air-exposure values, p less than 0.02, n = 5). These potent lipid mediators, originally derived from human AM, may play an important role in the mechanisms of O3 lung toxicity.
Sarcolemmal calcium transporters in myocardial ischemia.

To determine the potential pathophysiologic role of alterations in sarcolemmal Ca2+ transport mechanisms, we investigated the effects of up to 120 min of global ischemia in the rabbit heart on the three major Ca2+ transport proteins in the sarcolemma: the Na+-Ca2+ exchanger, the ATP-dependent Ca2+ pump, and the L-type Ca2+ channel. We purified sarcolemmal vesicles from control rabbit hearts and rabbit hearts made ischaemic for 20, 30, 60, 90, and 120 min. Purification of K+-p-nitrophenylphosphatase activity was about 30-fold compared to the initial homogenate, and was the same for control and ischemic hearts. We measured the initial velocity of Na+-Ca2+ exchange and found no inhibition after 20 min of ischemia, a 22% reduction in Vmax after 30 min of ischemia, and approximately a 50% reduction in Vmax after 60, 90, and 120 min of ischemia. At no time was there any change in the Ca2+ affinity of the Na+-Ca2+ exchanger. Solubilization and reconstitution of the Na+-Ca2+ exchanger into asolectin vesicles restored the velocity to the same level as control reconstituted vesicles after 60 min of ischemia, but not after 90 or 120 min of ischemia. In contrast to Na+-Ca2+ exchange, the initial velocity of the sarcolemmal ATP-dependent Ca2+ pump was unaffected by up to 2 h of ischemia. The number of L-type Ca2+ channels, measured by nitrendipine binding, was reduced by 21% after 60 min of ischemia. Decreased Ca2+ efflux due to direct inhibition of the Na+-Ca2+ exchanger, as well as inhibition by low pH and increased intracellular Na2+ in ischemia, probably contribute to Ca2+ overload and irreversible myocyte injury. Conversely, decreased Ca2+ influx due to decreased availability of L-type Ca2+ channels, as well as decreased capacity for reversed Na+-Ca2+ exchange, could contribute to contractile dysfunction during ischemia and myocardial stunning following reperfusion.
A geometric approach to forbidden minors for GF(3)

Abstract A new proof is given based on known results about embeddings of geometric lattices in projective spaces, of the finiteness of the set of forbidden minors for matroid representation over GF (3). This approach is more abstract than previous ones in that it does not depend on explicitly producing the minors in question, and for this reason it is hoped that further progress can be made along these lines on the question of finiteness of the set of forbidden minors for arbitrary GF ( q ).
Modeling of power delivery into 3D chips on silicon interposer

While three-dimensional (3D) technology has several advantages for power delivery, an integrated chip-level, interposer-level, and package-level power distribution network in through-silicon-via (TSV)-based 3D system has to be modeled and evaluated. This paper reports on modeling of power delivery into 3D chip stacks on a silicon interposer/packaging substrate using a novel hybrid approach, i.e., combining the electromagnetic (EM) and analytic simulations. We intentionally partition the real stack-up structure of a 3D power network into separate components, i.e., package vias and traces, C-4 solders, interposer TSVs and planar wires, μ-C4 solders, chip TSVs, and on-chip power grids with node capacitors, decoupling capacitors and active current loads. All the passive RLGCs for each component are extracted using an EM simulation tool at a given working frequency point. We then assemble all the components back into a corresponding equivalent circuit model with those EM extracted RLGC values, thus to analyze the supply voltage (V dd )variation over time for 3D systems in a manner of maximum accuracy and efficiency.
High dynamic range SIMS depth profiling on in situ ion‐beam‐generated mesas using the ion microscope

The dynamic range of SIMS depth profiles of high-dose ion implants can often be improved by removing the influence of the highly doped crater walls from the depth profile. This is accomplished either by collapsing the primary beam raster or by using specialized sample preparation techniques such as the mini-chip or dot-etching methods developed by von Criegern et al. The main limitations with the sample preparation techniques are that they are labor and time-intensive and are not applicable to all substrate types. By a simple modification of the raster circuits of an ion microscope, it is possible to generate, by sputtering, a mesa structure that is subsequently profiled under normal conditions. This approach offers a rapid, flexible method of mesa preparation that is amenable to all sample materials. The principal disadvantage with the use of the ion microscope for this analysis is that a significant memory effect can result from the dopant species that are sputtered during the preparation of the mesa structure.
Aspects of Peace Economics

The Economics of Peace can be modeled as a basic multi-game system composed of economicgames played between and among ﬁrms and consumers in each of two nations, domestic pressuregames played by ﬁrms, consumers, and the government within each nation, and political gamesplayed between the governments of the two nations. The integrated study of the basic system isgiven in the account of two-level games (Putnam, 1988). The details of these games were sketchedin Dacey (1994, 1996-a) and are updated here via the results obtained in the assassin modelspresented in Carlson and Dacey (2009, forthcoming). While the ﬁeld has made numerous advancesin the last sixteen years, the conclusion of Dacey (1994) still holds — Peace Economics, as initiallycharacterized by Isard (1994) and Polachek (1994), consists in the resolution of conﬂicts arisingin the multi-game system. Since the games are played rationally, the tools of Peace Economics arethe tools of the general theory of rational choice.KEYWORDS: peace economics, rational choice, two-level games, assassin models
A marmoset T-lymphocyte protein related to defined human serum immunoglobulin and fragments.

Current concepts of the antigen-specific receptor of thymus-derived (T) lymphocytes suggest that this molecule bears immunoglobulin (Ig) variable (V) regions, but does not represent a classical serum antibody. We immunized rabbits with a globulin fraction obtained from an in vitro cultured marmoset T cell lymphoma line which expressed surface components related to immunoglobulins. Quantitative immunoprecipitation and competition radioimmunoassay studies carried out using characterized monoclonal human Igs and their chains and fragments show that this rabbit antiserum, raised against a T cell product, reacts with a particular, conformational VH-determinant which is formed by interaction with lambda light chains and with two mu chain (IgM) related determinants. Neither mu chain determinant is a major isotype specific marker, and each occurs only on certain distinct subsets of serum mu chains. One is located in the Fc fragment; the location of the other mu related determinant is not known. These results show that this rabbit antiserum recognizes both variable and constant region determinants on the T cell receptor heavy chain. Rabbit antibody to the T cell product which cross-reacts with serum mu chain was isolated by immune affinity chromatography on Sepharose-derivatized covalently with one particular reactive IgM protein, the Waldenstrom macroglobulin Can (kappa mu). This antibody precipitated a biosynthetically-labelled component of approximate M.W. 70,000 as assessed by polyacrylamide gel electrophoresis in Na Dod SO4-containing buffers. These data support the conclusion that certain T cells express and synthesize a molecule related to Ig VH-regions which also has a constant region sharing antigenic markers with IgM subpopulations.
Virus mutators and antimutators: roles in evolution, pathogenesis and emergence

Virus mutators (mutant alleles that confer a higher mutant-frequency phenotype than that of the wild type) and antimutators (mutant alleles that confer a lower mutant-frequency phenotype) were discovered in bacteriophage T4 over three decades ago, but there is only limited detailed knowledge about such genetic variants in viruses that infect humans and threaten public health. The creation of mutators and antimutators during the course of viral infection (particularly in the case of RNA viruses) could play a pivotal role in virus evolution, pathogenesis and emergence, and could also frustrate antiviral therapy.
Long-Term Field Performance of Pervious Concrete Pavement

The work described in this paper provides an evaluation of an aged pervious concrete pavement in the Northeastern United States to provide a better understanding of the long-lasting effects of placement techniques as well as the long-term field performance of porous pavement, specifically in areas susceptible to freezing and thawing. Multiple samples were taken from the existing pavement and were examined in terms of porosity and unit weight, compressive and splitting tensile strength, and the depth and degree of clogging. It was concluded that improper placement and curing led to uneven pavement thickness, irregular pore distribution within the pervious concrete, and highly variable strength values across the site, as well as sealed surfaces that prevented infiltration.
Axial Allylation on the diosphenol claisen rearrangement

Abstract A 5:1 preference for axial vs . equatorial allylation is shown in the Claisen rearrangement of the conformationally-rigid diosphenol allyl ether 1 .
On movements of language—within self, of self, about self, and between selves: Commentary on language and self

Experiences acquire meaning and gain significance through narration and narratives do not mechanically signify experiences. The nature of visualization and understanding of self and the world aroun...
Changes in properties of nonaqueous elastomeric impression materials after storage of components.

Abstract Statement of problem. Storage stability, or shelf life, is a critical property of perishable dental materials. Purpose. The purpose of this investigation was to document changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. Material and methods. Materials investigated included a polyether impression material, a polysulfide material (light, regular, and heavy consistencies), and an addition-reaction silicone material (light, regular, heavy, and putty consistencies). Tests included viscosity of individual pastes, elastic recovery, working and setting times, strain in compression, dimensional change, creep compliance, and tear energy. Means and standard deviations were calculated for each test interval. Statistical analysis included 2-way ANOVA (variables: time and storage condition) and comparison to baseline values using 1-way ANOVA (variable: time) and Scheffe's multiple comparison test ( P ≤.05) within each material, consistency, and test. Results. Results over 72 months revealed changes in viscosity, working/setting times, elastic recovery, and creep compliance. Separation of components was seen with polysulfide and addition silicone materials. Some batches of polysulfide base paste and polyether reactor paste solidified in the tube. Conclusion. Most batches of the materials and consistencies tested remained efficacious well past their designated shelf lives under a variety of storage and use conditions. Data for the addition-reaction silicone impression material changed little during the 72-month testing period; thus, the material may be considered relatively storage stable. Creep compliance was the most precise storage-stability indicator. The storage stability of perishable materials should be addressed in American Dental Association Specifications. (J Prosthet Dent 2001;85:73-81.)
Plastochron Determination in Ranunculus using Carbon-14 Dioxide

DETERMINATION of the plastochron, or time interval between the formation of successive leaf primordia, suffers from the difficulty of establishing the age of a primordium at any particular stage of development. An autoradiographic technique has been successfully used for obtaining an estimate of the plastochron of Ranunculus by indirect means.
Effects of orienting instructions, feedback-information, and trait-anxiety level on state-anxiety.

This study evaluated the effects of orienting instructions and feedback-information on state anxiety (A-state) for Ss who differed in trait anxiety (A-trait). A-state and A-trait were measured by the State-Trait Anxiety Inventory. Differential orienting instructions (ego vs task) had no effect on change in A-state scores from a pretest to a test period. However, differential feedback-information was a significant determinant of change in A-state, with failure-feedback inducing greater increases in A-state than either no feedback or success-feedback. The largest differential increase in A-state scores between Ss high and low in A-trait occurred with the failure-feedback, though this effect only approached statistical significance.
Interstellar molecules and the origin of life

Synopsis of the various views expressed at the conference held at NASA Ames Research Center in February 1971 on the relationship of interstellar molecules to the origin of life, intended to provide a basis for future discussion and work in this area. The topics covered include: a summary of molecules discovered, the interstellar environment, laboratory measurements, chemical evolution, and exobiology.
Late gene function in bacteriophage T4 in the absence of phage DNA replication.

Abstract Under certain conditions the late genes of coliphage T4 may function in the absence of phage DNA replication. Quasi-late gene function is the function of certain late genes in the absence of both phage DNA replication and the product of the maturation gene 55. It does not depend on how phage DNA synthesis is prevented. Replication-uncoupled late gene function is late gene function from unreplicated DNA in the absence of phage ligase, and is still under the control of gene 55. It is most efficient if phage DNA replication is prevented by a mutation in the phage gene (43) for DNA polymerase. Both quasi-late gene function and replication-uncoupled late gene function are enhanced by the presence of mutations controlling a phage exonuclease (gene 46 or 47).
Correcting the Corrections

This article is a comment on recent statements that the work of early IQ testers and other scientists has been distorted. It also argues that the Pioneer Fund, a major source of support for studies...
Chitin synthetase activity is a dispensable function forNeurospora crassa protoplasts

Abstract Polyoxin B inhibits chitin synthetase activity and chitin synthesis ofNeurospora crassa slime andos-1 protoplasts, but in contrast to its effect onwild type, does not inhibit growth. It appears that chitin synthesis (chitin synthetase activity) is a dispensable function forNeurospora protoplasts, but is nondispensable for mycelial strains.
Immobilization of lipase enzyme in polyvinyl alcohol (PVA) nanofibrous membranes

Abstract Lipase enzyme from Candida rugosa (E.C. 3.1.1.3) has been successfully immobolized in 100–500 nm diameter fibers via electrospinning of aqueous mixtures of lipase and polyvinyl alcohol (PVA). Enzyme loading in these bicomponent fibers reached as high as 50%. The catalytic activity of the fiber bound lipase was the same as the crude enzyme, showing no adverse effects from either electric charges or PVA on the structure or functions of the enzyme proteins. Thermal behaviors and enzyme activities showed the lipase protein molecules to be dispersed among a semi-crystalline PVA matrix. Most significantly, the lipase-loaded bicomponent fibers exhibited far superior activity than the crude enzyme following exposures to elevated temperatures and humidity. The lipase/PVA bicomponent fibers could be rendered insoluble in water by chemical cross-linking with glutaraldehyde (GA) in ethanol, however, with reduced activities. The fibrous and porous structures of the bicomponent fibers were retained upon the cross-linking.
Study of the charge-state model for electrophoretic variation using isoelectric focusing of esterase-5 from Drosophila pseudoobscura.

VARIOUS neutral models have been proposed to account for the observed levels of enzyme polymorphism in natural populations1–5. One such model, the charge-state or ladder-rung model2, has been suggested to be appropriate for the available electrophoretic data. The model assumes that the only amino acid substitutions detectable by electrophoresis would involve unit charge changes—substitution of a charged for an uncharged residue—and because of charge redundancy alleles would fall into phenotypic classes of equal net charge3,4. Thus an electrophoretic variant would be a heterogeneous molecular entity, rather than the product of a unique allele. It was proposed that these charge classes would be evenly spaced in electrophoretic mobility, because unit charge changes would be reflected as unit jumps in mobility, but Johnson6 has questioned this on the grounds that no two charged group substitutions should result in identical net charge changes. He argued that there would be no charge redundancy and that there would be a continuum of charged variants. It was also recognised that while many substitutions involving uncharged residues would probably go undetected, some could cause conformational changes which would be resolved by electrophoresis. This concern has been borne out by the electrophoretic data: although many enzymes fit the expectations for neutral alleles contingent on the charge-state model7,8, others, including some esterases, do not. The mobilities of variants of these esterases are not evenly spaced, and rare variants are often observed at intermediate as well as extreme electrophoretic mobilities. These characteristics have been attributed to the presence of conformation, as well as charge, variability. We have investigated the relative importance of charge and conformational change in producing electrophoretic variation by examining variants at the Est-5 locus of Drosophila pseudoobscura by isoelectric focusing; this allows charge balance to be examined in the absence of conformational variation. The results indicate that while the observed charge changes fit a charge-state model, conformational differences exist which may account for a substantial amount of the additional variation revealed at this locus by conventional electrophoresis.
Structure of the Francisella tularensis enoyl-acyl carrier protein reductase (FabI) in complex with NAD + and triclosan

Enoyl-acyl carrier protein reductase (FabI) catalyzes the last rate-limiting step in the elongation cycle of the fatty-acid biosynthesis pathway and has been validated as a potential antimicrobial drug target in Francisella tularensis. The development of new antibiotic therapies is important both to combat potential drug-resistant bioweapons and to address the broader societal problem of increasing antibiotic resistance among many pathogenic bacteria. The crystal structure of FabI from F. tularensis (FtuFabI) in complex with the inhibitor triclosan and the cofactor NAD+ has been solved to a resolution of 2.1 A. Triclosan is known to effectively inhibit FabI from different organisms. Precise characterization of the mode of triclosan binding is required to develop highly specific inhibitors. Comparison of our structure with the previously determined FtuFabI structure (PDB code 2jjy) which is bound to only NAD+ reveals the conformation of the substrate-binding loop, electron density for which was missing in the earlier structure, and demonstrates a shift in the conformation of the NAD+ cofactor. This shift in the position of the phosphate groups allows more room in the active site for substrate or inhibitor to bind and be better accommodated. This information will be crucial for virtual screening studies to identify novel scaffolds for development into new active inhibitors.
Biochemical and pharmacological studies with 1-β-d-arabinofuranosylcytosine in man

Abstract Cytosine arabinoside, labeled with tritium, was administered to five patients with far-advanced neoplasms. The analog was rapidly deaminated to uracil arabinoside; the latter accounted for between 86 and 96 per cent of the radioactivity excreted in the urine. Incorporation of tritium-labeled cytidine into DNA by suspensions of human leukemic leukocytes was inhibited in the presence of cytosine arabinoside. Although administration of cytosine arabinoside at therapeutic levels depressed the ability of leukemic leukocytes to incorporate cytidine into DNA in vitro , there was no correlation between the degree and duration of this effect and the clinical response to the drug. Tritium-labeled cytosine arabinoside entered human leukemic leukocytes very rapidly when incubated with the cells in vitro ; there was a small but significant incorporation of the analog into both DNA and RNA.
Computing Floquet–Bloch modes in biperiodic slabs with boundary elements

Abstract A new variational formulation for the boundary element computation of Floquet–Bloch solutions to the Helmholtz equation is derived. The method is applicable to geometries that are layered in the vertical and biperiodic in two horizontal directions. The discretization leads to a nonlinear Hermitian eigenvalue problem which is solved using a homotopy approach. Numerical examples demonstrate that with the boundary element approach a high accuracy can be achieved with a small number of degrees of freedom in the discretization.
Double-valence-fluctuating molecules and superconductivity.

We discuss the possibility of ''double-valence-fluctuating'' molecules, having two ground-state configurations differing by two electrons. We propose a possible realization of such a molecule, and experimental ways to look for it. We argue that a weakly coupled array of such molecules should give rise to a strong-coupling Shafroth-Blatt-Butler superconductor, with a high transition temperature.
Turbulent bubbly two-phase flow data in a triangular duct

Abstract Multidimensional bubbly two-phase flow data was obtained in an isosceles triangular duct having D h = 40 mm and L / D = 73. The data include local measurements of phase distribution, velocity and Reynolds stresses at 10,000 Re 1 bubble = 1250. The measurements were performed with single sensor and X-sensor cylindrical hot film probes of 0.025 mm diameter. These small probes have good bubble penetration characteristics so they are capable of the simultaneous measurement of the liquid phase instantaneous velocity and the phase indicator function. These data are useful for the validation of multidimensional two-fluid CFD models.
Development of Brugia pahangi infections and lymphatic lesions in male offspring of female jirds with homologous infections

The development of Brugia pahangi infections and associated gross lymphatic lesions were compared in male offspring from B. pahangi-infected and uninfected female jirds. The numbers of adult worms recovered did not differ between groups but a greater number of offspring of infected females (92%) developed circulating microfilaraemias than did individuals from uninfected females (50%). Intralymphatic granulomatous thrombi, lymphatic dilatations and lymphatic lesion scores were significantly reduced in offspring from infected mothers.
Operant force emission during differential reinforcement of low rates

Ten rats were reinforced on a DRL 15-sec schedule of food reinforcement. The operandum and associated laboratory computer equipment permitted the measurement of peak force and interresponse time (IRT) for individual responses. Terminal performance on the DRL schedule was characterized by an inverse relationship between peak force and IRT such that short IRTs were accompanied by relatively high peak force, whereas generally lower peak forces were emitted after IRTs of 10 sec or longer.
Sound representation methods for spectro-temporal receptive field estimation

The spectro-temporal receptive field (STRF) of an auditory neuron describes the linear relationship between the sound stimulus in a time-frequency representation and the neural response. Time-frequency representations of a sound in turn require a nonlinear operation on the sound pressure waveform and many different forms for this non-linear transformation are possible. Here, we systematically investigated the effects of four factors in the non-linear step in the STRF model: the choice of logarithmic or linear filter frequency spacing, the time-frequency scale, stimulus amplitude compression and adaptive gain control. We quantified the goodness of fit of these different STRF models on data obtained from auditory neurons in the songbird midbrain and forebrain. We found that adaptive gain control and the correct stimulus amplitude compression scheme are paramount to correctly modelling neurons. The time-frequency scale and frequency spacing also affected the goodness of fit of the model but to a lesser extent and the optimal values were stimulus dependant.
Receptor-mediated radiopharmaceuticals

Abstract The development of radiotracers with defined affinities for specific receptor systems is a potentially useful approach to the design of radiopharmaceuticals for nuclear medicine. Radiolabelled ligands, such as hormones and neurotransmitters, are being synthesized and evaluated as diagnostic tools for diseases which can be characterized either by changes in receptor concentration or by novel receptor expression. Since the utility of a radiopharmaceutical is dependent upon the achievement of adequate ratios of target to nontarget accumulation of radioactivity, design of radiotracers via the receptor approach attempts to exploit those systems in which receptor is present in significantly higher concentration at potential target sites such as tumors. Receptor-mediated radiotracers are also currently being used in animal models to investigate the normal tissue distribution of drug and hormone receptors and the in-vivo pharmacokinetics of receptor binding. The successful development of receptor-avid radiopharmaceuticals will depend on the ability to synthesize ligands of high specific radioactivity which retain the high affinity and binding specificity for the receptor after radiolabelling.
Tetrahydrocannabinol Isomers and Homologues: Contrasted Effects of Smoking

TWO isomers of tetrahydrocannabinol (THC) are found in natural marijuana preparations. 99 per cent is in the form of Δ1(9)-THC, which is very active when taken orally or smoked1,2. A Δ3-THC homologue, synhexyl (pyrahexyl), has been found to be about one-third as active as Δ1-THC, given orally to the same individuals2. The study I report here compared measured doses of Δ1-THC, the Δ3-homologue (synhexyl), and Δ3-THC smoked by the same individuals, using a placebo and blind controls.
Median infectious dose (ID50) of porcine reproductive and respiratory syndrome virus isolate MN-184 via aerosol exposure

The median infectious dose (ID(50)) of porcine reproductive and respiratory syndrome (PRRS) virus isolate MN-184 was determined for aerosol exposure. In 7 replicates, 3-week-old pigs (n=58) respired 10l of airborne PRRS virus from a dynamic aerosol toroid (DAT) maintained at -4°C. Thereafter, pigs were housed in isolation and monitored for evidence of infection. Infection occurred at virus concentrations too low to quantify by microinfectivity assays. Therefore, exposure dose was determined using two indirect methods ("calculated" and "theoretical"). "Calculated" virus dose was derived from the concentration of rhodamine B monitored over the exposure sequence. "Theoretical" virus dose was based on the continuous stirred-tank reactor model. The ID(50) estimate was modeled on the proportion of pigs that became infected using the probit and logit link functions for both "calculated" and "theoretical" exposure doses. Based on "calculated" doses, the probit and logit ID(50) estimates were 1 × 10(-0.13)TCID(50) and 1 × 10(-0.14)TCID(50), respectively. Based on "theoretical" doses, the probit and logit ID(50) were 1 × 10(0.26)TCID(50) and 1 × 10(0.24)TCID(50), respectively. For each point estimate, the 95% confidence interval included the other three point estimates. The results indicated that MN-184 was far more infectious than PRRS virus isolate VR-2332, the only other PRRS virus isolate for which ID(50) has been estimated for airborne exposure. Since aerosol ID(50) estimates are available for only these two isolates, it is uncertain whether one or both of these isolates represent the normal range of PRRS virus infectivity by this route.
Ethanol causes decreased partitioning into biological membranes without changes in lipid order

One of the adaptive responses of cell membranes to chronic ethanol consumption is the acquisition of a resistance to fluidization or disordering of the lipids by ethanol in vitro and a reduced partitioning of ethanol into the membrane (membrane tolerance). The degree to which the effects on partitioning and lipid disordering share common features has not previously been explored and in addition the relevance of the value of lipid order in the absence of added ethanol (baseline lipid order) to membrane tolerance has not been established. The location in the bilayer and the nature of the modification underlying these effects is also unknown. The effect of chronic ethanol treatment was examined using 5-doxyl decane as a model hydrophobic compound. Its partitioning into the membranes was determined by utilizing its ability to quench fluorophores (1,6-diphenyl-2,3,5-hexatriene and 3- and 12-anthroyl stearates) by collisional quenching. The partition coefficient of 5-doxyl decane into the bilayer central region was reduced as a result of the chronic ethanol treatment. The effect could also be demonstrated in vesicles of phospholipids and was lost 4 days after withdrawal of the ethanol from the diet. These results closely parallel those relating to resistance to lipid disordering and suggest that both techniques detect a common modification. Lipid order was assessed using fluorescence anisotropy measurements of a range of fluorophores, including those used to determine the partitioning properties of the membrane. No effect of chronic ethanol treatment on lipid order was found, either in the intact membranes or in vesicles of extracted phospholipids. This suggests that changes in baseline order are not critical features of membrane tolerance in liver microsomes. In addition it appears that the altered partitioning of the 5-doxyl decane into the central region of the membrane is not related to lipid order changes in this region. The reduced partitioning of 5-doxyl decane may be a reflection of a redistribution in the lipid bilayer, perhaps due to modifications in other locations in the membrane, such as the lipid head group region.
Effect of the product layer on the kinetics of the CO2‐lime reaction

The kinetics of reaction between CO2 and lime is investigated in the range of 673 to 998 K with a view to examining the effects of product layer deposition and variations in the limestone calcination atmosphere. The reaction is initially rapid and chemically controlled and goes through a sudden transition to a much slower regime controlled by diffusion in the product CaCO3 layer. The magnitude of the estimated product layer diffusivity is in the range of 10−18 to 10−21 m2/s, the corresponding activation energy is 88.9 ± 3.7 kJ/mol below 688 K and 179.2 ± 7.0 kJ/mol above that temperature, suggestive of solid state diffusion. Plausible mechanisms are discussed.
Products of commutators and squares in free groups

Abstract Geometric proofs, using surface topology, are given for an upper bound of the rank of a subgroup determined by a quadratic equation in a free group.
ETHIONINE INCORPORATION INTO THE RAT CONCEPTUS.

Abstract The data presented have shown that ethionine is incorporated quickly and in substantial amounts into the amino acid pool and proteins of the mammalian fetus and placenta, that ethionine-containing proteins are fairly long-lived, and that ethionine injection is associated with an increase in pool methionine concentration. The data further suggest an initial stimulation of protein synthesis in the fetus and placenta followed by a degradation of and/or inhibition of synthesis of proteins of the fetus and placenta.
Development of lateral-directional departure criteria

Current departure prediction indicators for both open and closed loop flight are developed using the same rigorous analytical approach applied to a linear version of the aircraft model. Emphasis on the assumptions made and terms omitted indicate why the results are somewhat limited. A second approach is presented which is shown to lead to the same results as the first, but is more applicable to the nonlinear problem. Some ideas concerning the application of the linear methods to the nonlinear problem are presented.
Morphology of Bacterium tularense during its growth cycle in liquid medium as revealed by the electron microscope.

Abstract Electron microscopic studies of the morphology of Bacterium tularense during the various stages of its life cycle were carried out. A technique of preparation is described, based on direct adsorption of cells from liquid cultures onto copper containing metal layers. A growth curve was plotted for the moderately virulent strain 46 and specimens were prepared for electron microscopic study at each point of the curve. Cells with constrictions, suggesting reproduction by binary fission, were observed during active growth. During the death phase the cell walls became filamentously elongated, forming tubes about 30 to 40 mμ in diameter and up to several microns in length. The filamented cells, which appeared to be dead, showed little mechanical solidity and fractured easily into pieces corresponding to the forms visualized by Hesselbrock and Foshay with the aid of light microscopy. The results presented here do not support their contention that these minute forms are “true morphologic units” belonging to a developmental cycle and capable of reproduction, but indicate that these forms are disintegrated dead cells. It is therefore concluded that B. tularense does not have a complex life cycle like the pleuropneumonia group, but most likely has a mode of reproduction common to many other gram negative rods.
On the Piliavin & Piliavin Model of Helping Behavior: Costs Are in the Eye of the Beholder

Two field experiments tested the Piliavin and Piliavin cost-reward model of helping. The model predicts that the most helping should occur when the costs for helping are low and when the costs for not helping are high. The results of Experiment 1 provided partial support for this prediction, and the results of Experiment 2 were completely consistent with the model.
Charting the Islands of Memory

Exquisitely structured microcircuits in the hippocampus and entorhinal cortex (EC) were first sketched more than a century ago by the great Spanish neuroanatomist Ramon y Cajal. It has since become known that these circuits are components of a memory system that allows us to recall facts and past events from our lives. Two reports on pages 891 and 896 of this issue describe newly discovered circuits formed by a population of neurons in the EC, which congregate in distinctive clusters referred to as “patches” by Ray et al. ( 1 ) and as “islands” by Kitamura et al. ( 2 ). Both studies suggest that these island cells may play important roles in learning and memory.
Renin Release from Nonclipped Kidneys of 2K-1C Hypertensive Rats

This study examined renin release and renal function of the nonclipped kidney of 2K-1C rats (HYPER) with hypertension of 3 to 4 weeks duration. Kidneys from uninephrectomized rats (UN) served as controls. The kidneys were removed and perfused in vitro and renin release was compared under basal conditions and then under stimulated conditions using (a) a 50 mm Hg reduction in perfusion pressure (LP), (b) beta-receptor stimulation with isoproterenol (ISOP), or (c) perfusion with a low calcium solution (LCa). Basal perfusate flow, glomerular filtration rate, urine flow, sodium excretion, and basal renin release were all lower in HYPER kidneys than UN kidneys. UN kidneys showed striking increases in renin release with all three stimuli employed. HYPER kidneys showed a significant but attenuated response to ISOP and showed no detectable response to LP or LCa. Renin content of HYPER kidneys was found to be 28% of the renin content of UN kidneys. The results show that chronic hypertension leads to increased renal vascular resistance, reduced glomerular filtration, and reduced solute excretion in the nonclipped kidney. The results suggest that a reduction in renin content plays a major role in the reduced rates of basal renin release and the attenuated renin responses to a number of stimuli observed in this experimental model.
Cholesterol contents of U.S. and imported goat milk cheeses as quantified by different colorimetric methods

Abstract Cholesterol concentrations of 15 varieties of U.S. and imported commercial goat milk cheeses were evaluated by different extraction and colorimetric determination procedures. The majority of the caprine milk cheeses were high moisture containing soft type varieties, where moisture contents of the products were not exactly equated with cholesterol contents. The range of cholesterol levels (wet basis) in the experimental cheeses was 80–147 mg/100 g. Cholesterol contents of Texas Chevre, U.S. goat milk Gouda, and white hard goat cheeses were: 120.8, 124.8, and 95.4 mg/100 g cheese on a wet basis, and 39.3, 71.5, and 59.2 mg/100 g on a dry basis, respectively. On a wet basis, the Texas Chevre with pepper and herbs variety had the lowest (80.9 mg/100 g), while the imported variety of Royal Province with garlic and herbs contained the greatest amount of cholesterol (146.8 mg/100 g). However, cheese with the highest dry matter (Norwegian Gjetost) showed the greatest cholesterol (107.0 mg/100 g) among all tested goat cheese varieties on a dry basis. Cholesterol in goat milk cheeses of this study determined by the colorimetric method was higher than in cow milk cheeses determined by the gas chromatographic (GC) method in previous reports. It was concluded that the differences in cholesterol between goat and cow milk cheeses may be attributable to the differences in analytical procedure rather than species of milk or cheese, because cow milk reportedly contains slightly higher cholesterol than goat milk. The turbidity of the sample solution in colorimetric procedures might also be partially accountable for differences in cholesterol among different varieties especially in spice added cheeses. The colorimetric method using o -phthalaldehyde was more consistent and about 20% less variable than using FeSO 4 -acetic acid as the color developing agent in the determination of cholesterol.
Therapeutic implications of electrolyte, water, and nitrogen losses during recovery from protein-calorie malnutrition.

The importance of recognizing the altered physiologic status of the child with protein-calcium malnutrition at admission and during rehabilitation is emphasized by the difference in continuing losses and in growth requirements in these periods. Features of great significance are the inability to concentrate urine at admission and during early rehabilitation, the increased urine volume resulting from higher protein intakes, and the increased dermal losses which occur with early and late catch-up growth. For the child at admission, it is suggested that whole cow's milk diluted two parts with one part of a solution of 15 per cent dextrimaltose and 1.5 per cent potassium chloride will meet the water and electrolyte requirements when fed at the rate of at least 150 ml. per kilogram per day. If the child is committed to the catabolic state by gastrointestinal disturbances, an oral or intravenous infusion of a solution containing 55 mEq. of K and 25 mEq. of Na at an average rate of 120 ml. per kilogram per day will provide for the average continuing losses or maintenance requirements of water and electrolytes.
Origin of apparent swain–schaad deviations in criteria for tunneling

Vibrational analysis calculations have been conducted in an effort to understand the origins of apparently anomalous relationships reported between κ H /κ T and κ D /κ T kinetic isotope effects. The actual isotopic substitutions used in previous work are more complex than a simple comparison between H/T and D/T isotope effects. The relationships between the actual isotope effects determined in these studies amount to tests of two standards of conventional isotope effect theory, the rule of the geometric mean (or the lack of isotope effects on isotope effects) and the Swain-Schaad rule. Model calculations illustrate the importance of violations of the rule of the geometric mean (over Swain-Schaad deviations) arising in models that incorporate both explicit reaction-coordinat coupling of two isotopic sites and reaction-coordinate tunneling. Implications for experimental studies of tunneling using apparent Swain-Schaad exponents are discussed
Detection of Pd(III) and Pd(IV) Intermediates during the Aerobic Oxidative C–C Bond Formation from a Pd(II) Dimethyl Complex

The dimethyl PdII complex (MeN4)PdIIMe2 (MeN4 = N,N′-dimethyl-2,11-diaza[3,3](2,6)pyridinophane) is readily oxidized by dioxygen in the presence of protic solvents to selectively eliminate ethane. UV–vis, EPR, ESI-MS, and NMR studies reveal the formation of several PdIII and PdIV intermediates during the aerobically induced C–C bond formation reaction, including the key intermediate [(κ3-MeN4)PdIVMe3]+, which leads to ethane elimination. The latter complex was also synthesized independently and structurally characterized to reveal a distorted octahedral geometry that is proposed to promote facile reductive elimination. Overall, this study represents a rare example of aerobic oxidation of an organometallic PdII precursor that leads to a well-defined PdIV species, which undergoes selective C–C bond formation under ambient conditions.