cssi/SciSciGPT-SciSciNet huggingface dataset:
Thermal decomposition of methyl oleate hydroperoxides and identification of volatile components by gas chromatography‐mass spectrometry

The role of methyl oleate hydroperoxides as precursors of volatile compounds was investigated by thermal decomposition in the injector port of a gas chromatograph attached to a computerized mass spectrometer. The major volatile compounds identified correspond to those formed from triolein heated in air at 192 C.
Cohesive Energy of Potassium

The cellular method has been applied to a calculation of the cohesive energy of metallic potassium. The crystal potential is taken from a self-consistent field with exchange for the potassium ion. An approximate exchange interaction between the valence and the core electrons was included. The cohesive energy was found to be 18.5 or 19.3 cal/mole according as Pines' or Wigner's expression for the correlation energy is used, and the effective mass to be 86% of the free-electron mass. The experimental value is 22.6 cal/mole.
Decrease in deformation rate as a possible precursor to the next Parkfield earthquake

CRUSTAL deformations along fault zones are monitored because they show the accumulation and possible premonitory release of strain energy before major earthquakes. On the Parkfield segment of the San Andreas fault the next mainshock (local magnitude ML=5.7) is expected to occur between 1983 and 1993, based on the relatively regular recurrence of characteristic earthquakes in 1857, 1881, 1901, 1922, 1934 and 19661. A concerted monitoring effort is therefore underway at Parkfield, with the aim of detecting precursory changes in observable quantities that can be measured reliably2. Here we report data from two geodetic lines crossing the San Andreas fault near Parkfield which show that the rate of shortening decreased by ˜20% starting in August 1986. This change coincided with a rate decrease of 45% for earthquakes of ML⩾2.1 in the area3,4. Both phenomena may have been caused by temporary locking of the fault surface, or a decrease in strain accumulation rate, and they are interpreted as intermediate-term precursors to the next Parkfield earthquake.
Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of 199Hg chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations

Calculations of the nuclear magnetic resonance chemical-shielding tensors of a suite of mercury-containing materials using various cluster models for the structures provide a stringent test of the procedures for forming models and for calculation with various methods. The inclusion of higher co-ordination shells in the molecular clusters permits quantum chemical calculations of 199Hg chemical-shielding tensor elements within 3% of the experimental values. We show that it is possible to reduce the size of computationally expensive molecular-cluster calculations with limited effect on calculated NMR parameters by carefully introducing the frozen core approximation. The importance of the relativistic Hamiltonian for accurate predictions of chemical-shielding values is demonstrated within the molecular cluster approach. The results demonstrate that careful design of a cluster to represent the solid-state structure, inclusion of relativistic components in the Hamiltonian at least at the spin–orbit level, and judicious use of approximations are essential to obtain good agreement with experimental results.
Pre-imaginal experience and nestmate brood recognition in the carpenter ant, Camponotus floridanus

Abstract Worker larve of the carpenter ant were reared from the first instar to pupation in the presence of workers and pupae from a foreign colony. Following metamorphosis to adulthood, they were transferred to a group of workers and pupae from a different colony. When offered a pupa from each colony at 5–7 days post-emergence, the experimental workers preferentially licked pupae of the colony with which they were familiarized during larval experience. At later ages, they exhibited no significant preference. These results are consistent with the transient influence of pre-imaginal experience on nestmate brood recognition previously reported in the ant Cataglyphis cursor. However, control C. floridanus workers, familiarized with a single colony during both larval and adult experience, licked pupae from that colony and pupae from an unfamiliar colony without preference. In a second control experiment, older workers taken directly from their natal colony also failed to lick nestmate pupae preferentially, but did pick up and retrieve them significantly earlier than non-nestmates, suggesting that licking may not be an adequate measure of recognition. Colony recognition learned during larval life could be enhanced by a temporary estrangement, after which workers exhibit a preference for pre-imaginally familiar brood that might not otherwise be manifest.
Narrowing the Gap: An Example of Student/Practitioner Collaboration in Classrooms

There is general agreement that the relationship between university business schools and the business community should become closer in the future, but neither group has many suggestions as to how this might be done. This paper describes a student/practitioner collaborative project that helped students bridge the gap between academic and work worlds. In addition, the project also helped narrow the gap between faculty members and practitioners. Benefits and costs to individuals and organizations are discussed.
Biodegradable Polymers for the Environment

Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Extraordinary progress has been made in the development of practical processes and products from polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products. In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet.
1-Methyl-Tryptophan Synergizes with Methotrexate to Alleviate Arthritis in a Mouse Model of Arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease with no known cure. Current strategies to treat RA, including methotrexate (MTX), target the later inflammatory stage of disease. Recently, we showed that inhibiting indoleamine-2,3-dioxygenase (IDO) with 1-methyl-tryptophan (1MT) targets autoantibodies and cytokines that drive the initiation of the autoimmune response. Therefore, we hypothesized that combining 1MT with MTX would target both the initiation and chronic inflammatory phases of the autoimmune response and be an effective co-therapeutic strategy for arthritis. To test this, we used K/BxN mice, a pre-clinical model of arthritis that develops joint-specific inflammation with many characteristics of human RA. Mice were treated with 1MT, MTX, alone or in combination, and followed for arthritis, autoantibodies, and inflammatory cytokines. Both 1MT and MTX were able to partially inhibit arthritis when used individually; however, combining MTX + 1MT was significantly more effective than either treatment alone at delaying the onset and alleviating the severity of joint inflammation. We went on to show that combination of MTX + 1MT did not lower inflammatory cytokine or autoantibody levels, nor could the synergistic co-therapeutic effect be reversed by the adenosine receptor antagonist theophylline or be mimicked by inhibition of polyamine synthesis. However, supplementation with folinic acid did reverse the synergistic co-therapeutic effect, demonstrating that, in the K/BxN model, MTX synergizes with 1MT by blocking folate metabolism. These data suggest that pharmacological inhibition of IDO with 1MT is a potential candidate for use in combination with MTX to increase its efficacy in the treatment of RA.
How to become a pathogen

For most bacterial species, virulence is viewed as a derived state, whereby pathogens acquire certain loci and are rendered virulent. The majority of virulence genes in Salmonella are present in closely related nonpathogenic species, and most genes known to be confined to the salmonellae are not essential for virulence. Alternative evolutionary scenarios may explain the origins of pathogenicity in Salmonella.
α-β target tracking systems: a survey

This paper is a survey of the α-β target tracking process: historical developments and significant estimation and control concepts. The α-β filter is a popular algorithm for radar/target tracking and is often integrated with missile intercept systems. The algorithm is simple: virtually anyone can understand its operation, use it and it works virtually all the time. With this premise, this survey paper addresses fundamental control concepts such as stability, noise reduction, transient response, order reduction, maneuver idenification, noise estimation, track fusion, prediction/smoothing and adaptive tracking. As a survey guide, this paper considers the following questions: Where/when was the first significant reported α-β target tracker and what was its technical message? Why do Radar/Systems Engineers like to use the α-β target tracker? How do Radar/Systems Engineers view the α-β target tracker function? How do Control Engineers view the α-β target tracker function? One of the first relationship found between the α and β parameters was β=α2/(2-α); how many other relationships are there and which one is right? The noise reduction ratio is a useful performance measure; what simple performance does optimal target tracker have? Can one improve the α-β target tracker performance? And if so, how much of an improvement? Can the α-β target tracker be self-tuned? Can multiple α-β target trackers be efficiently fused?
Notes on the floral biology of Nymphaea elegans (nymphaeaceae) in Texas

Abstract Various aspects of the pollination biology and floral behavior of Nymphaea elegans Hooker (Nymphaeaceae) are described. Flowers open each morning for 3 successive days. First-day flowers are protogynous with the stigmata secreting a fluid which fills the perigynous cup. As potential pollen-covered pollinators are attracted and enter first-day flowers, they land on the vertical, but flexible, inner stamens which bend and the insects fall into the stigmatic fluid. The stigmatic fluid washes pollen from the insects and pollination is achieved. Second- and third-day flowers are functionally staminate, lacking the stigmatic fluid. The pollination biology of N. elegans is compared to the pollination syndromes described in other species of Nymphaea .
Transport of folate compounds, pterins and adenine in L1210 mouse leukemia cells

L1210 mouse leukemia cells provide a convenient model for examining the mechanisms and components involved in the active transport of various metabolites and drugs. One of these transport systems exhibits a broad specificity for folate compounds, including 4-amino antagonists such as methotrexate. The primary substrate for this system is 5-methyltetra-hydrofolate (Kt = 1 microM), the principal circulating form of the vitamin in mammals. 5-Formyltetrahydrofolate (Kt = 5 microM) and Methotrexate (Kt = 5 microM) are also taken up efficiently, but folate (Kt = 100 microM) is a relatively poor substrate. Vmax for this system is ca. 15 pmoles/min/mg protein. Energy for substrate internalization is provided by an anion-exchange mechanism, and regulation appears to be mediated by cyclic AMP. The system can be inhibited irreversibly by treatment of the cells with photo-activated azido AMP or carbodiimide-activated folate compounds. The latter method allows the membrane-associated binding protein to be labeled in situ, thereby providing a means for identifying it during subsequent solubilization and purification. Guidance for this latter project is provided by previous experience in the purification to homogeneity of a similar folate-binding protein from Lactobacillus casei. L1210 cells also contain an efficient system for the transport of adenine (Kt = 20 microM; Vmax = 200 pmoles/min/mg protein). Uptake of adenine is linked with its conversion to AMP via PRPP-dependent adenine phosphori-bosyltransferase. Pterins, which have a close structural similarity to adenine (as well as to a portion of the folate molecule), are also transported into L1210 cells. Transport of [3H] 6-hydroxymethylpterin (Kt = 20 microM) was inhibited by 6-formylpterin, 6-methylpterin and 6-carboxypterin with Ki values of 42, 100 and 350 microM, respectively. Adenine (Ki = 20 microM) and various other purines were also good inhibitors of pterin transport. Present evidence indicates that adenine and pterins use separate transport systems, but isolation of the components of these systems may further delineate their interrelationships.
Calmodulin Mediates the Stimulatory Effect of 3,5,3′-Triiodothyronine on Adenylate Cyclase Activity in Rat Thymocyte Plasma Membranes

We have previously demonstrated that T3 increases adenylate cyclase activity in rat thymocyte plasma membranes by a mechanism that is calcium dependent. In the present studies we have examined whether calmodulin participates in this response to T3. Initial experiments provided evidence that calmodulin is involved in regulating the activity of the guanyl nucleotide-dependent adenylate cyclase in this tissue. Thus, compared with findings in freshly prepared membranes, dialysis of thymocyte plasma membrane preparations for 20 h at 4 C decreased their calmodulin concentrations from an initial value of approximately 600 ng/100 micrograms protein by about 50% and decreased adenylate cyclase activity by approximately 80%. Although storage of the same preparations under comparable conditions resulted in no change in calmodulin content, it caused an approximate 30% decrease in adenylate cyclase activity. Addition of calmodulin had no effect on adenylate cyclase activity in fresh or stored membrane preparations, but produced a dose-dependent increase in enzyme activity in preparations that had been dialyzed. Further, when added to freshly isolated membranes, three calmodulin antagonists, trifluoperazine, calmidazolium, and calmodulin antibodies, all produced a concentration-dependent inhibition of adenylate cyclase activity, and this was completely reversed in all cases by the addition of high concentrations of exogenous calmodulin. The stimulation of guanyl nucleotide-dependent adenylate cyclase activity that T3 induced in fresh membrane preparations was present in membranes that had been stored, but was absent in those that had been dialyzed. In addition, the response to T3 in fresh membranes was inhibited or abolished by all three calmodulin antagonists. Both in dialyzed membranes and in the presence of antagonists, the response to T3 was restored by the addition of exogenous calmodulin. We conclude that calmodulin influences the activity of the guanyl nucleotide-dependent adenylate cyclase in rat thymocytes and ultimately mediates the stimulation of enzyme activity that T3 produces. Such mediation very likely explains the calcium-dependent nature of the stimulatory effect of T3 on thymocyte adenylate cyclase activity.
Bound state methods for elastic scattering phase shifts

Abstract Three methods are investigated for obtaining elastic phase shifts in the scattering of electrons from atoms and ions that use a bound-state representation of the scattering wavefunction. Results for singlet p-wave scattering by H and by He + are compared with previous calculations.
An integrative review of comprehensive sex education for adolescent girls in Kenya.

This article identifies and reviews comprehensive sex education programs (CSEPs) available to adolescent females in Kenya discusses barriers to implementing CSEPs in Kenya and highlights the role of nurses in improving and institutionalizing available CSEPs in Kenya. The authors conducted a systematic search of six databases and other Internet sources to identify CSEPs currently available to adolescent girls in Kenya. Five were identified. The CSEPs were evaluated using established criteria. All of the CSEPs were well designed and almost all were implemented with fidelity. Four of the five CSEPs met all of the criteria for well-designed CSEPs with only one showing lack of sustainability. Tuko Pamoja (We Are One) shows promise for wider implementation. CSEPs are a valid intervention leading to the reduction of teenage pregnancy HIV/AIDS and sexually transmitted infections. The reach of the identified CSEPs varies and sustainability is challenging due to lack of government and community support lack of funding and unsustainable teaching modalities. Nurses can serve as liaisons between adolescents the community and the Kenyan government in promoting CSEPs. Nurses should be more readily used in educating community members and policy-makers about the need for CSEPs in all Kenyan high schools. Nursing students can also be used in their community health role to teach curricula of CSEPs. Nurses should advocate for all adolescents to access reproductive health services and for all healthcare providers to provide comprehensive reproductive health care to them.
Rhythmic histone acetylation underlies transcription in the mammalian circadian clock

In the mouse circadian clock, a transcriptional feedback loop is at the centre of the clockwork mechanism. Clock and Bmal1 are essential transcription factors that drive the expression of three period genes (Per1-3) and two cryptochrome genes (Cry1 and Cry2). The Cry proteins feedback to inhibit Clock/Bmal1-mediated transcription by a mechanism that does not alter Clock/Bmal1 binding to DNA. Here we show that transcriptional regulation of the core clock mechanism in mouse liver is accompanied by rhythms in H3 histone acetylation, and that H3 acetylation is a potential target of the inhibitory action of Cry. The promoter regions of the Per1, Per2 and Cry1 genes exhibit circadian rhythms in H3 acetylation and RNA polymerase II binding that are synchronous with the corresponding steady-state messenger RNA rhythms. The histone acetyltransferase p300 precipitates together with Clock in vivo in a time-dependent manner. Moreover, the Cry proteins inhibit a p300-induced increase in Clock/Bmal1-mediated transcription. The delayed timing of the Cry1 mRNA rhythm, relative to the Per rhythms, is due to the coordinated activities of Rev-Erbalpha and Clock/Bmal1, and defines a new mechanism for circadian phase control.
Landscape response to tectonic forcing: Digital elevation model analysis of stream profiles in the Mendocino triple junction region, northern California

The topographic evolution of orogens is fundamentally dictated by rates and patterns of bedrock-channel incision. Quantitative field assessments of process-based laws are needed to accurately describe landscape uplift and denudation in response to tectonics and climate. We evaluate and calibrate the shear stress (or similar unit stream-power) bedrock-incision model by studying stream profiles in a tectonically active mountain range. Previous work on emergent marine terraces in the Mendocino triple junction region of northern California provides spatial and temporal control on rock-uplift rates. Digital elevation models and field data are used to quantify differences in landscape morphology associated with along-strike northwest to southeast changes in tectonic and climatic conditions. Analysis of longitudinal profiles supports the hypothesis that the study-area channels are in equilibrium with current uplift and climatic conditions, consistent with theoretical calculations of system response time based on the shear-stress model. Within uncertainty, the profile concavity (𝛉) of the trunk streams is constant throughout the study area (𝛉 ≈ 0.43), as predicted by the model. Channel steepness correlates with uplift rate. These data help constrain the two key unknown model parameters, the coefficient of erosion ( K ) and the exponent associated with channel gradient ( n ). This analysis shows that K cannot be treated as a constant throughout the study area, despite generally homogeneous substrate properties. For a reasonable range of slope-exponent values ( n ), best-fit values of K are positively correlated with uplift rate. This correlation has important implications for landscape-evolution models and likely reflects dynamic adjustment of K to tectonic changes, due to variations in orographic precipitation, and perhaps channel width, sediment load, and frequency of debris flows. The apparent variation in K makes a unique value of n impossible to constrain with present data.
Host choice and success of gulls and terns kleptoparasitizing brown pelicans

Abstract Little agreement has been reached as to whether kleptoparasitic gulls,Larusspp., preferentially target adult, juvenile or just successful brown pelicans,Pelecanus occidentalis, and no studies have determined kleptoparasite success when targeting pelicans of different age classes. In 1991 and 1992, foraging brown pelicans and kleptoparasitic laughing gulls,L. atricilla, roseate terns,Sterna dougallii, and sandwich terns,S. sandvicensis, were studied to determine host choice, kleptoparasite success and exploitability of pelicans by gulls and terns. Adult pelicans had a higher foraging success than juveniles in 1991 but not in 1992. Gulls and terns were more likely to target adult pelicans than juveniles, but the strength of this effect was stronger in 1991 than in 1992. Gulls and terns were also more likely to target successful than unsuccessful pelicans, and the strength of this effect did not differ between years. Kleptoparasites had a higher probability of success when targeting adult rather than juvenile pelicans and when targeting successful rather than unsuccessful pelicans. Successful pelicans were more likely than unsuccessful pelicans to use evasive manoeuvres, and prey capture success among kleptoparasites was greater when successful pelicans used evasive manoeuvres. Handling times did not differ between the two pelican age classes. Kleptoparasitic gulls and terns may not necessarily differentiate between ‘reliable’ and ‘exploitable’ victims, as previously suggested, because in the present study adult pelicans were the more reliable class, as well as the more exploitable class. 1997 The Association for the Study of Animal Behaviour
Riparian habitat fragmentation and population persistence of the threatened valley elderberry longhorn beetle in central California

Abstract We studied regional- and local-scale occurrence of the threatened valley elderberry longhorn beetle (VELB) in central California to further understand population dynamics of this habitat specialist in fragmented riparian woodlands. In 1991 and 1997, we surveyed 65 riparian sites along the Sacramento River and 13 of its tributaries for VELB occurrence by examining elderberry bushes for characteristic emergence holes. We also compared VELB local abundance with that of its more common closest relative, the California elderberry longhorn beetle (CELB). Our research revealed that in the northern half of its geographic range, the VELB occurs in drainages that appear to function as distinct, relatively isolated metapopulations. Survey sites within drainages exhibited turnover in site occupancy between 1991 and 1997, but between-drainage site turnover was rare. Sites that were colonized in 1997 were surrounded by a greater number of occupied sites than those that were not colonized, suggesting that VELB colonization of isolated sites or drainages is constrained by limited dispersal. VELB exit holes consistently occurred: (1) in clumps of elderberry bushes rather than in isolated bushes in both survey years; (2) in elderberry branches 5–10 cm in diameter; and (3) in branches
Zirconium amide, halide, and alkyl complexes supported by tripodal amido ligands derived from cis, cis-1,3,5-triaminocyclohexane

Zirconium complexes containing the chelating triamido ligands [cis,cis-1,3,5-(C6F5N)3C6H9]3- and {cis,cis-1,3,5-[3,5-(CF3)2C6H3N]3C6H9}3- are reported. The dimethylamido complexes [cis,cis-1,3,5-(C...
Stimulation of in vivo antibody production and concanavalin-A-induced mouse spleen cell mitogenesis by prolactin

Regulation of the immune system by neuroendocrine hormones is receiving increased attention. Prolactin, a hormone normally associated with lactation, has been shown recently to reconstitute immunosuppressed hypophysectomized rats. The present studies demonstrate that prolactin administration to normal mice results in a biphasic stimulation of antibody production to sheep red blood cells. While 100 and 200 micrograms bovine prolactin/animal stimulated antibody production, 400 micrograms had no effect. Potentiation of lectin-induced T-cell mitogenesis by prolactin was also biphasic. As the concentration of prolactin increased the incorporation of [3H]thymidine into the cells first increased and then decreased. Decreasing serum prolactin levels with the dopaminergic agonist bromocriptine resulted in a reduction of antibody titers to sheep erythrocytes and a modulation of thymic weight. These data show that prolactin can stimulate the immune system in a biphasic manner and that a reduction in the basal levels of this hormone results in an attenuated immune response.
Colonization of Arabidopsis thaliana with Salmonella enterica and enterohemorrhagic Escherichia coli O157:H7 and competition by Enterobacter asburiae

Enteric pathogens, such as Salmonella enterica and Escherichia coli O157:H7, have been shown to contaminate fresh produce. Under appropriate conditions, these bacteria will grow on and invade the plant tissue. We have developed Arabidopsis thaliana (thale cress) as a model system with the intention of studying plant responses to human pathogens. Under sterile conditions and at 100% humidity, S. enterica serovar Newport and E. coli O157:H7 grew to 10(9) CFU g(-1) on A. thaliana roots and to 2 x 10(7) CFU g(-1) on shoots. Furthermore, root inoculation led to contamination of the entire plant, indicating that the pathogens are capable of moving on or within the plant in the absence of competition. Inoculation with green fluorescent protein-labeled S. enterica and E. coli O157:H7 showed invasion of the roots at lateral root junctions. Movement was eliminated and invasion decreased when nonmotile mutants of S. enterica were used. Survival of S. enterica serovar Newport and E. coli O157:H7 on soil-grown plants declined as the plants matured, but both pathogens were detectable for at least 21 days. Survival of the pathogen was reduced in unautoclaved soil and amended soil, suggesting competition from indigenous epiphytes from the soil. Enterobacter asburiae was isolated from soil-grown A. thaliana and shown to be effective at suppressing epiphytic growth of both pathogens under gnotobiotic conditions. Seed and chaff harvested from contaminated plants were occasionally contaminated. The rate of recovery of S. enterica and E. coli O157:H7 from seed varied from undetectable to 19% of the seed pools tested, depending on the method of inoculation. Seed contamination by these pathogens was undetectable in the presence of the competitor, Enterobacter asburiae. Sampling of 74 pools of chaff indicated a strong correlation between contamination of the chaff and seed (P = 0.025). This suggested that contamination of the seed occurred directly from contaminated chaff or by invasion of the flower or silique. However, contaminated seeds were not sanitized by extensive washing and chlorine treatment, indicating that some of the bacteria reside in a protected niche on the seed surface or under the seed coat.
Evolutionary diversification of the mammalian defensins.

Defensins are cysteine-rich cationic peptides that function in antimicrobial defense in both invertebrates and vertebrates. Three main groups of animal defensins are known: insect defensins; mammalian α-defensins and vertebrate β-defensins. It has been difficult to determine whether these molecules are homologous or have independently evolved similar features, but overall the evidence favors a distant relationship. The best evidence of this relationship is structural, particularly from their overall three-dimensional structure and from the spacing of half-cystine residues involved in intra-chain disulfide bonds. Some evidence favors a closer relationship between vertebrate β-defensins and insect defensins than between the two groups of vertebrate defensins. Examination of nucleotide substitutions between recently duplicated mammalian defensin genes shows that the rate of nonsynonymous (amino-acid-altering) substitution exceeds that of synonymous substitution in the region of the gene encoding the mature defensin. This highly unusual pattern of nucleotide substitution is evidence that natural selection has acted to diversify defensins at the amino acid level. The resulting rapid evolution explains why it is difficult to reconstruct the evolutionary history of these molecules.
The nerve fiber content of Amblystoma aneurogenic limbs

The nerveless state of larval Amblystoma limbs rendered aneurogenic by removal of the embryonic neural tube and crest was examined in silver stained light microscope sections and in sections prepared for electron microscopy. The regenerates of these forelimbs were similarly studied. The sections were compared with those taken from the limb and regenerate of normal animals to which the aneurogenic animal had been parabiosed for survival. Nerve fibers were found in 62% of the “aneurogenic” limbs studied at ultrastructural levels. The number of fibers was less than one-tenth of that in the normal limb and thus well below the expected level required for regeneration. The number of fibers counted with the electron microscope exceeded those observed with the light microscope, emphasizing the limitations of silver stains for the small unmyelinated axons.
The development of hypothetical reference in the speech of young children

The data obtained in two investigations (one a longitudinal/cross-sectional naturalistic study, the other a quasi-experimental study) demonstrate that preschool age children have the capacity for hypothetical reference. However, the data also indicate that this capacity for hypothetical reference operates within certain constraints, particularly early in the preschool years. Specifically, future hypothetical reference is an earlier acquisition than past hypothetical reference; reference to single hypothetical events appears sometime prior to reference to sequences of hypothetical events; and accuracy is better in self-initiated than other-initiated hypothetical reference. The implications of these findings are discussed.
Washed RBCs prevent recurrent acute hypotensive transfusion reactions.

Objectives: To examine whether a liver transplant patient, who was not taking an angiotensin-converting enzyme inhibitor and developed two episodes of hypotension with systolic pressure in the 50s within minutes of starting an RBC transfusion, may have had a disturbance in the production and metabolism of bradykinin and des-Arg[9][1]-BK. Methods: All patient information was obtained by reviewing the electronic medical record, the transfusion service database, and transfusion reaction investigation records. Results: The blood pressure returned to normal once the transfusions were discontinued. In an effort to mitigate the acute hypotension, the blood products were washed. Subsequently, the patient received three additional packed RBC transfusions without further incidents of hypotension. Conclusions: Our experience suggests that washing the products was an acceptable and effective preventative measure to avoid further acute hypotensive transfusion reactions in patients unable to metabolize these vasodilators present in the donor units. [1]: #ref-9
Calculating wave-generated bottom orbital velocities from surface-wave parameters

Near-bed wave orbital velocities and shear stresses are important parameters in many sediment-transport and hydrodynamic models of the coastal ocean, estuaries, and lakes. Simple methods for estimating bottom orbital velocities from surface-wave statistics such as significant wave height and peak period often are inaccurate except in very shallow water. This paper briefly reviews approaches for estimating wave-generated bottom orbital velocities from near-bed velocity data, surface-wave spectra, and surface-wave parameters; MATLAB code for each approach is provided. Aspects of this problem have been discussed elsewhere. We add to this work by providing a method for using a general form of the parametric surface-wave spectrum to estimate bottom orbital velocity from significant wave height and peak period, investigating effects of spectral shape on bottom orbital velocity, comparing methods for calculating bottom orbital velocity against values determined from near-bed velocity measurements at two sites on the US east and west coasts, and considering the optimal representation of bottom orbital velocity for calculations of near-bed processes. Bottom orbital velocities calculated using near-bed velocity data, measured wave spectra, and parametric spectra for a site on the northern California shelf and one in the mid-Atlantic Bight compare quite well and are relatively insensitive to spectral shape except when bimodal waves are present with maximum energy at the higher-frequency peak. These conditions, which are most likely to occur at times when bottom orbital velocities are small, can be identified with our method as cases where the measured wave statistics are inconsistent with Donelan's modified form of the Joint North Sea Wave Project (JONSWAP) spectrum. We define the ''effective'' forcing for wave-driven, near-bed processes as the product of the magnitude of forcing times its probability of occurrence, and conclude that different bottom orbital velocity statistics may be appropriate for different problems.
The differential rational representation algebra on a linear differential algebraic group

In [2], the author began the study of affine differential algebraic groups. The study of such groups is somewhat analogous to the study of algebraic groups. However, the non-Noetherian character of the differential rings associated with differential algebraic sets has made it necessary to develop new techniques for the study of algebraic differential equations. The reader is referred to Kolchin [7]. It is well-known, easy to prove, and central to the study of algebraic groups, that the ring of everywhere defined rational functions on an affine algebraic set is the coordinate ring. The differential ring of everywhere defined differential rational functions on an affine differential algebraic set is not the differential coordinate ring, and is not, in general, finitely generated as a differential algebra. For this reason, an affine differential algebraic group need not be linear, i.e., it need not be differentially rationally isomorphic to a differential algebraic matric group. If G is an affine differential algebraic group, the differential algebra, generated over the coefficient field by the coordinate functions of all the linear differential rational representations of G, is called the dz@rentiaZ rational representation algebra on G, and is denoted by W(G). The purpose of this note is to prove the following theorem and its corollaries:
Phase investigations of the AlIr system

Abstract The phase behavior of the AlIr system has been studied using differential thermal analysis, electron microprobe analysis, X-ray diffraction, chemical analysis and X-ray fluorescence. Our work confirms the existence of four compounds: Al9Ir2, Al3Ir, Al2.7Ir and AlIr. We also observed an additional intermetallic phase, with a stoichiometry corresponding to Al13Ir4; however, this compound exhibits a complex X-ray pattern and currently no structure has been determined. Peritectic temperatures were determined for Al9Ir2 (900 °C), Al13Ir4 (1015 °C) and Al3Ir (1450 °C). The Al2.7Ir phase is stable to above 1450 °C, and the congruent melting temperature of AlIr is 2120 ± 20 °C. The solubility of aluminum in iridium was measured between 1085 and 1850 °C, and the maximum solid solubility was extrapolated to 18 at.% at 2058 °C. The maximum solid solubility of iridium in aluminum was measured to be less than 0.1 at.%. A phase diagram for the AlIr system is presented.
Serum levels of PCDDs and PCDFs among workers exposed to 2,3,7,8-TCDD contaminated chemicals

Abstract The National Institute for Occupational Safety and Health (NIOSH) collected serum from workers exposed to chemicals contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and from unexposed referents. A subset of serum samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In addition to a marked difference in serum levels between workers and referents for 2,3,7,8-TCDD, there was a small but significant difference for 2,3,7,8-PnCDF and 1,2,3,4,7,8-HxCDF. Funding was received for this study from the Agency for Toxic Substances and Disease Registry.
The Direct and Indirect Effects of Offender Drug Use on Federal Sentencing Outcomes

Objectives The federal sentencing guidelines constrain decision makers’ discretion to consider offenders’ life histories and current circumstances, including their histories of drug use and drug use at the time of the crime. However, the situation is complicated by the fact that judges are required to take the offender’s drug use into account in making bail and pretrial detention decisions and the ambiguity inherent in decisions regarding substantial assistance departures allows consideration of this factor. In this paper we build upon and extend prior research examining the impact of an offender’s drug use on sentences imposed on drug trafficking offenders.
An X-ray spectroscopic investigation of bis(dithiolene)molybdenum(IV,V,VI) and -tungsten(IV,V,VI) complexes: Symmetrized structural representations of the active sites of molybdoenzymes in the DMSO reductase family and of tungstoenzymes in the AOR and F(M)DH families

Molybdenum and tungsten oxotransferase and hydroxylase enzymes catalyze the generalized reaction X + H2O ↔ XO + 2H+ + 2e- involving substrate and product X/XO. All such enzymes contain one or two pterin dithiolene ligands bound to a molybdenum or tungsten atom in the enzyme cofactor. Recent investigations in these laboratories together with earlier work by others have afforded a set of 10 complexes, all structurally characterized by X-ray diffraction, that are relevant to the active sites of several families of enzymes containing two pterin dithiolenes: [MIVO(bdt)2]2- (1, 6), [MV(bdt)2]1- (2, 7), [MIV(OSiButPh2)(bdt)2]1- (3, 8), [MVIO2(bdt)2]2- (4, 9), and [MVIO(OSiButPh2)(bdt)2]1- (5, 10) [M = Mo (1−5), W (6−10); bdt = benzene-1,2-dithiolate(2−)]. In particular, complexes 3 and 5 simulate the reduced and oxidized sites, respectively, of one DMSO reductase. This set of complexes of accurately known structure provides a heretofore unavailable opportunity to examine by X-ray absorption spectroscopy (XAS) t...
DIFFERENTIAL REINFORCEMENT OF VOCAL DURATION1

The effects of differential reinforcement of vocal duration were examined in a series of experiments in which each of 28 subjects (Ss) emitted a vowel whenever a light was flashed. In the first phase of each experiment, a penny was dispensed after each of 20 responses. In the second and subsequent phases, only those responses whose durations exceeded a criterion were reinforced; when 10 successive reinforcements were presented, one phase was terminated and the next begun. The criterion for reinforcement in each phase was determined by a different schedule in each of six experiments; it ranged from 80 to 120 per cent of the mean duration of the 10 terminal responses in the prior phase. Differential reinforcement effected a large and systematic change in the duration of vocal responses as long as the responses selected for reinforcement had a sufficiently high probability of occurrence. This requirement was formulated as the difference between the criterion duration and the mean duration of the terminal responses in the prior phase, divided by their standard deviation. This statistic, named the shaping index, was correlated with the number of responses emitted before each phase was terminated. It was found to be large whenever the shaping process failed. Many Ss failed to tact the reinforcement contingency despite marked changes in their vocal behavior and extensive probing by a questionnaire, administered at the end of each session.
Flight experience with a backup flight-control system for the HiMAT research vehicle

The NASA Dryden Flight Research Facility is conducting flight tests of two remotely piloted, subscale, advanced fighter configurations; the tests are part of the Highly Maneuverable Aircraft Technology (HiMAT) project. Closed-loop primary flight control is performed from a ground-based cockpit and digital computer in conjunction with an up/down telemetry link. A significant feature of these vehicles is an on-board, digitally active, backup control system designed to recover the vehicle in the event of a transfer from primary control. Automatic transfers occur upon certain critical ground or airborne system malfunctions. Control modes are provided that enable a ground or airborne controller to guide the vehicle to a safe landing. This paper describes the features, operational development, and flight evaluation of the HiMAT backup flight control system.
Effects of 5-trifluoromethyldeoxyuridine upon deoxythymidine kinase.

Abstract 5-Trifluoromethyl-2′-deoxyuridine (F 3 TdR) can be phosphorylated by deoxythymidine (TdR) kinase as easily as can the normal substrate, TdR, or the pyrimidine analog, 5-bromodeoxyuridine. F 3 TdR inhibited the formation of thymidine monophosphate (d-TMP) from TdR. With 5.0 mμmoles TdR in the incubation system, the 50 per cent inhibitory concentration of F 3 TdR was 10 mμmoles. The Michaelis constant. K m , and the inhibition constant, K t , for TdR and for F 3 TdR were calculated to be 3.3 × 10 −6 and 3.7 × 10 −6 M. The inhibition of d-TMP formation by F 3 TdR was also a complex function of the adenosine triphosphate concentration.
Intramolecular dynamics in molecule-surface collisions: Excitation, dissociation, and selectivity of reactivity

Excitation of internal vibrational modes of molecules scattered from surfaces is here considered. Emphasis is placed upon a mechanism which follows if either charge transfer between the solid and molecule occurs or alternatively, if the intramolecular geometry varies with molecule-surface separation. The excitation is studied in terms of both analytic quantum wavepacket dynamics over simplified model potential energy surfaces and numerical classical trajectories over more realistic surfaces. Conditions under which the analytic models provide realistic descriptions of the collision dynamics are determined. For the most part considerations are restricted to incident kinetic energies greater than ≈1 eV where interesting chemistry is most likely to occur. Finally, the theoretical model is applied to several problems of experimental relevance. In particular, translational to vibrational energy transfer is studied as it pertains to dissociative adsorption, vibrationally excited scattered molecules, dissociatively scattered diatomic molecules, and selectivity in the fragmentation distributions of scattered polyatomic molecules.
Effect of Graft Selection on the Incidence of Postoperative Infection in Anterior Cruciate Ligament Reconstruction

Background: Knee joint infection is a potentially devastating complication of anterior cruciate ligament (ACL) reconstruction. There is a theoretical increased risk of infection with the use of allograft material.Hypothesis: An allograft ACL reconstruction predisposes patients to a higher risk of bacterial infection.Study Design: Cohort Study; Level of evidence, 3.Methods: All primary ACL reconstructions performed at our institution between January 2002 and December 2006 were reviewed; 3126 total procedures were identified. A retrospective medical record review was performed to determine the incidence of infection, offending organism, time after surgery until presentation, infection treatment, and graft salvage as an outcome of graft choice.Results: Of the 3126 ACL reconstructions, 1777 autografts and 1349 allografts were performed. Eighteen infections were identified (0.58%). Infections occurred in 6 of the 1349 allografts (0.44%), 7 of the 1430 bone-patellar tendon-bone (BPTB) autografts (0.49%), and 5 ...
Age-Dependent Cardiovascular Effects of Verapamil in Newborn Swine

ABSTRACT. Since there are limited studies concerning the hemodynamic effects of verapamil in pediatric patients, cardiovascular effects of clinical doses (100 or 300 μ/kg) of verapamil, given as a 2-min intravenous infusion, were examined in sodium pentobarbital anesthetized swine, aged 1 day (n=15) and 2 wk (n=18). Aortic and left ventricular pressures, index of left ventricular contractility, heart rate, and phasic superior mesenteric, renal, and femoral arterial flows were recorded; mean aortic pressure and vascular resistances were calculated. Maximum changes in cardiovascular function (mean %Δ ± SEM) occurred at the end of the infusion. Mean aortic pressure and index of left ventricular contractility decreased in all animals; responses were larger in magnitude with the higher dose. By 30 min after infusion of 300 μ/kg verapamil had ended, mean aortic pressure in both 1 day and 2 wk olds and index of left ventricular contractility and femoral flow in 1 day olds were still decreased. During infusion of verapamil, heart rate decreased (—11.6 ± 2.9) to the high dose in 1 day olds but increased (+6.4 ± 2.7) to 100 and 300 μ/kg verapamil in 2 wk olds. After infusion of 300 μ/kg verapamil ended, heart rate decreased and reached the nadir (—10.0 ± 2.9) by 10 min in 2 wk olds. Decreases in renal resistance (—7.6 ± 1.7) were not dose dependent while superior mesenteric resistance decreased (—12.9 ± 2.7) only to low dose verapamil in 2 wk olds. In 1 day olds decreases in renal and superior mesenteric resistance were not sustained throughout the infusion. The results indicate that verapamil has both age- and dose-dependent cardiovascular effects in newborn swine and suggest that verapamil be used with caution in infants.
Does skin moisture influence the blood flow response to local heat? A re-evaluation of the Pennes model.

Pennes first described a model of heat transfer through the limb based only on calories delivered from a heat source, calories produced by metabolism and skin blood flow. The purpose of this study was to determine the effect of a moist versus a dry heat source on the skin in eliciting a blood flow response to add data to this model. Ten subjects were examined, both male and female, with a mean age of 32.5 ± 11.6 years, mean height of 172.8 ± 12.3 cm, and mean weight of 77.6 ± 19.5 kg. Skin temperature was measured by a thermocouple placed on the skin and skin blood flow measured by a laser Doppler flow meter. The results of the experiments using a dry heat pack (commercially available chemical 42°C cell dry heat source), moist hydrocollator pack (72.8°C) separated from the skin by eight layers of towels, and whirlpool at 40°C, showed that moist heat caused a significantly higher skin blood flow (about 500% greater) than dry heat (p < 0.01). Most of the greater increase in skin blood flow with moist heat w...