cssi/SciSciGPT-SciSciNet huggingface dataset:
Spectral encoding of x-ray/optical relative delay

We present a new technique for measuring the relative delay between a soft x-ray FEL pulse and an optical laser that indicates a sub 25 fs RMS measurement error. An ultra-short x-ray pulse photo-ionizes a semiconductor (Si3N4) membrane and changes the optical transmission. An optical continuum pulse with a temporally chirped bandwidth spanning 630 nm – 710 nm interacts with the membrane such that the timing of the x-ray pulse can be determined from the onset of the spectral modulation of the transmitted optical pulse. This experiment demonstrates a nearly in situ single-shot measurement of the x-ray pulse arrival time relative to the ultra-short optical pulse.
Relativistic suppression of wave packet spreading.

We investigate numerically the solution of Dirac equation and analytically the Klein-Gordon equation and discuss the relativistic motion of an electron wave packet in the presence of an intense static electric field. In contrast to the predictions of the (non-relativistic) Schrodinger theory, the spreading rate in the field’s polarization direction as well as in the transverse directions is reduced.
The role of urinary kininogen in the regulation of kinin generation

The role of urinary kininogen in the regulation of kinin generation. The kallikrein-kininogen-kinin system has been postulated to play a role in the regulation of blood pressure and modulation of renal salt and water transport. The activity of this system has usually been determined by measurements of urinary kallikrein excretion. However, urinary kallikrein rarely correlates with simultaneously measured urinary kinins. To further evaluate the factors influencing urinary kinin excretion, we evaluated the role of urinary kininogen in this system. Urines were analyzed from normal subjects and individuals with untreated essential hypertension and end-stage renal disease. Intact urinary kininogen was significantly correlated with urinary kinins in normal subjects (r = 0.65, P=0.003) and essential hypertensives (r = 0.52, P=0.026). In both essential hypertension and end-stage renal disease, urinary kinins were significantly decreased (8.00 ± 1.93, 0.90 ± 0.18, P
Increased heparin binding in cystic fibrosis: a reflection of altered glycoprotein biosynthesis?

Summary: Some of the serum proteins which bind to heparin and contribute to the pH 5.57 “heparin binding capacity” of human serum are glycoproteins; those from cystic fibrosis serum were found to be 27% higher in fucose (methylpentose) content, 27% lower in sialic acid content, and 31% lower in hexose content when compared to heparin-precipitated serum glycoproteins from normal control subjects. Hexosamine content of the heparin-precipitated serum glycoproteins was the same. Results of this preliminary investigation indicate that altered carbohydrate composition in serum glycoproteins may affect significantly their heparin binding capacity. Speculation: The glycoprotein biosynthetic mechanism in cystic fibrosis is genetically altered and produces glycoproteins of abnormal carbohydrate composition which combine with normal, acidic, glycosaminoglycans to form insoluble, viscous complexes that hinder normal cellular and subcellular transport mechanisms and metabolic processes.
Productive Struggle in Middle School Mathematics Classrooms.

Prior studies suggest that struggling to make sense of mathematics is a necessary component of learning mathematics with understanding. Little research exists, however, on what the struggles look like for middle school students and how they can be productive. This exploratory case study, which used episodes as units of analysis, examined 186 episodes of struggles in middle school students as they engaged in tasks focused on proportional reasoning. The study developed a classification structure for student struggles and teacher responses with descriptions of the kinds of student struggle and kinds of teacher responses that occurred. The study also identified and characterized ways in which teaching supported the struggles productively. Interaction resolutions were viewed through the lens of (a) how the cognitive demand of the task was maintained, (b) how student struggle was addressed and (c) how student thinking was supported. A Productive Struggle Framework was developed to capture the episodes of struggle episodes from initiation, to interaction and to resolution. Data included transcripts from 39 class session videotapes, teacher and student interviews and field notes. Participants were 327 6th- and 7th-grade students and their six teachers from three middle schools located in mid-size Texas cities. This study suggests the productive role student struggle can play in supporting “doing mathematics” and its implications on student learning with understanding. Teachers and instructional designers can use this framework as a tool to integrate student struggle into tasks and instructional practices rather than avoid or prevent struggle.
Design and fabrication of an ultraviolet-visible coded aperture snapshot spectral imager

We describe the design and performance of a coded aperture spectral imager with a wide spectral range of 320 to 700 nm over 87 channels and 1988-by-1988 pixels of spatial resolution. A custom-designed relay lens was designed and built for the system, including a dispersive prism element in the collimated space of the relay lens. The optical design process, prescription, and performance are reported for the entire system, including calibration and alignment. Simulations of high-resolution spectral images are conducted to verify the reconstruction algorithm and relative resolution of the instrument compared to ground truth data. Measured data were taken with the instrument using both a random coded aperture and standard slit for spatial resolution comparisons. Finally, reconstructed spectral images from the instrument are presented of a sunlight-illuminated flower from 360 to 700 nm.
Allorecognition and chimerism in an invertebrate model organism

The presence of highly specific histocompatibility reactions in colonial marine invertebrates that lack adaptive immune systems (such as the sponges, cnidarians, bryozoans, and ascidians) provides a unique opportunity to investigate the evolutionary roots of allorecognition and to explore whether homologous innate recognition systems exist in vertebrates. Conspecific interactions among adult animals in these groups are regulated by highly specific allorecognition systems that restrict somatic fusion to self or close kin. In Hydractinia (Cnidaria:Hydrozoa), fusion/rejection responses are controlled by two linked genetic loci. Alleles at each locus are co-dominantly inherited. Colonies fuse if they share at least one haplotype, reject if they share no haplotypes, and display transitory fusion if they share only one allele in a haplotype A¢Â€Â“ a pattern that echoes natural killer cell responses in mice and humans. Allorecognition in Hydractinia and other marine invertebrates serves as a safeguard against st...
Lamellar-Hexagonal Phase Transition Kinetics Depend Strongly on Degree of Saturation

Phase transition temperatures of lipid-water systems have long been known to exhibit a strong dependence on the rate of heating or cooling. The difference between the phase transition temperatures seen on heating and cooling is known as the hysteresis. Using an optical technique, we have examined the hysteresis for two lipids, SOPE (1-Stearoyl-2-Oleoyl-sn-Glycero-3-Phosphoethanolamine) and DSPE (1,2-Distearoyl-sn-Glycero-3-Phosphoethanolamine. SOPE contains a saturated tail and an unsaturated tail, while in DSPE both tails are saturated. We find that the hysteresis exhibits a power law dependence on the temperature ramping rate and that the hysteresis is markedly reduced for the completely saturated lipid DSPE as compared to the mono-unsaturated lipid SOPE. In turn, the hysteresis of SOPE is markedly reduced compared to that of DOPE, a lipid with two mono-unsaturated tails.
High-speed flash exposure with compact digital cameras

A technique was developed to allow the use of external flash at image sensor exposure times lower than the manufacturer’s specified maximum sync speed of a compact digital camera. By correlating light meter measurements with brightness readings of a grey card, a method to use the digital camera image sensor to measure light from flash units was developed. The flash discharge curve was derived and integrated to develop a mathematical model for clipped flash output. Utilising experimental data, the model was validated and parameterised for flash units. A computer program was created to calculate settings for correct flash exposure.
Desired learning, disavowed learning: Scale-making practices and subverting the hierarchy of study abroad experiences

Abstract This article illustrates dynamic relations between the hierarchy of learning experience in study abroad and scale-making practices that assert a particular unit of comparison. The discourse of immersion prevalent in study abroad valorizes immersion in the host country’s life and downgrades spending time with compatriot students or in the classroom, creating a hierarchy of learning experience. This hierarchy posits that the study abroad student’s host and home countries are fundamentally different and internally homogeneous; hence immersion in any part of life in the host country teaches students something, whereas other students from their home country do not. Thus this article views privileging immersion as a scale-making practice that highlights the scale of the nation-state as the only unit of meaningful difference. Based on case studies of four American college students studying abroad in the UK, France and Spain in June–July 2011, this article shows that these students valued immersion yet also learned much in the classroom and by spending time with fellow American and other international students, practices disavowed/discouraged by the discourse of immersion. This challenged the hierarchy of learning experience upheld by the discourse of immersion; it as well subverted but also reinforced the discourse’s scale-making practice at the nation-state level. By examining these relationships between the hierarchy of learning and scale-making practice, this article shows that study abroad is less about encountering a homogeneous host society or producing “global citizens” than about learning to relate to people at the intersections of various regimes of difference.
ON THE MECHANISM OF ACETYLCHOLINESTERASE ACTION : THE ELECTROSTATICALLY INDUCED ACCELERATION OF THE CATALYTIC ACYLATION STEP

Brownian dynamics simulations of the encounter kinetics between the active site of the wild-type and Glu199 mutant of Torpedo californica acetylcholinesterase (TcAChE) with a charged substrate were...
Isotopic composition of atmospheric oxygen and nitrogen

High altitude air samples collected in glass bulbs during balloon flights up to heights of 87,000 ft were found to contain oxygen with a normal isotope ratio, deviations less than ±0·05%. Air samples collected in Aerobee rockets up to altitudes of 51·6 km contained nitrogen having a normal isotope ratio, deviations less than ±0·15%. The oxygen of the rocket samples contained a higher percentage of O18 than normal, but when an estimated correction was applied for the preferential loss of O16 by clean-up of oxygen by the steel collecting tanks, the O18 percentage of the oxygen in air at 51·6 km was normal to ±0·3%. Air collected at ground level in a number of locations all over the world contained oxygen having a normal isotope ratio to ±0·025%. Air pumped out of ocean water at different depths in the Pacific Ocean contained oxygen having a higher O18 percentage than normal; the less the percentage of oxygen in the sample, the greater was the O18 percentage. The oxygen isotope fractionation factor for the process consuming dissolved oxygen was 0·991. The nitrogen isotope ratio in dissolved ocean air was normal. The oxygen isotope fractionation factor for the clean-up or chemisorption of oxygen by steel was 1·026, while the factor was 1·061 for the clean-up of oxygen by copper.
Debittering Citrus Juices with β-Cyclodextrin Polymer

A β-cyclodextrin polymer was used to remove the bitter substances limonin and naringin from aqueous solution and from filtered orange and grapefruit juices using batch and continuous flow column treatments. Other components such as naringenin 7β-rutinoside, coumarins and flavonoids were removed, but the total soluble solids (°Brix), total acidity and ascorbic acid content of the juice were unchanged. The polymer could be regenerated by extraction with an organic solvent.
Molecular characterization of aLactococcus lactis bacteriophage F4-1

Abstract The genome of a bacteriophage that infects Lactococcus lactis F4-1 has been characterized and a region coding for several structural proteins cloned. L. lactis bacteriophage F4-1 is a small isometric bacteriophage with a genome of approximately 33 kilobases (kb) and complementary single-stranded ends. It has a burst size of 120 and a latent time of approximately 30 min. A 7·6-kb HindIII/EcoRI fragment has been cloned into E. coli and shown to code for the major capsid protein and at least four other proteins between 35 and 43 kDa. The region coding for these proteins lies on the right arm of the genome within 9 kb of the right cos site. Although the major capsid protein appears prominently in Coomassie blue stained SDS-PAGE preparation of L. lactis bacteriophage F4-1 the other proteins appear to be minor components of the bacteriophage capsid. A 3-kb Sau 3A fragment coding for the 35- and 43-kDa proteins was subcloned into both E. coli and L. lactis LM0230. Both proteins were expressed in either host presumably via their own promoter.
Circuit equation formulation of resistive wall mode feedback stabilization schemes

Recently, various schemes for controlling the resistive wall mode have been proposed. Here, the problem of resistive wall mode feedback control is formulated utilizing concepts from electrical circuit theory. Each of the coupled elements (the perturbed plasma current, the poloidal passive shell system and the active coil system) is considered as lumped parameter electrical circuits obeying the usual laws of linear circuit theory. A dispersion relation is derived using different schemes for the feedback logic. The various schemes differ in the choice of sensor signal, which is determined by some combination of the three independent circuit currents. Feedback schemes are discussed which can, ideally, completely stabilize the kink mode. These schemes depend, for their success, on a suitable choice for the location of the sensors. A feedback scheme based on sensing the passive shell eddy current is discussed which seeks to drive the feedback system response to a point of marginal stability. For realizable feedback gain factors, this feedback system can suppress the kink mode amplitude for times that are very long compared with the L/R time-scale of the passive shell system. The circuit equation approach discussed provides a useful means for comparing various control strategies for n ≥ 1 kink mode control, and allows useful analogies to be drawn between kink mode control and the control of n = 0 vertical position instabilities.
Characterisation of nonlinear thin films using logarithmic Hilbert transform

A new technique based on logarithmic Hilbert transform processing of Maker-fringe curves to characterise second-order optical nonlinear depth profile of thin films is described and demonstrated experimentally. This technique, being analytical, is faster than its iterative alternative. This is the first time that a Hilbert transform based analytical tool has been applied to characterise nonlinear thin films.
Boundedness theorems for dilators and ptykes

The main theorem of this paper is: If ƒ is a partial function from ℵ_1 to ℵ_1 which is ∑^1_1-bounded, then there is a weakly finite primitive recursive dilator D such that for all infinite α ϵ dom(ƒ), ƒ(α) ⩽ D(α). The proof involves only elementary combinatorial constructions of trees. A generalization to ptykes is also given.
Mass of Vesta

The asteroid 197 (Arete) approaches asteroid 4 (Vesta) within 0.04 astronomical unit once every 18 years. It may therefore be possible to determine the mass of Vesta from observations of Arete. From 72 observations a value of (1.20 ± 0.08) x 10-10 solar mass was derived, the indicated uncertainty being a probable error.
The Properties of the Neckel-Chini VRI System

Cousins (1980) data for 54 of the standard stars of Neckel and Chini (1980) and published measurements are used to investigate the properties of the Neckel-Chini VRI system. For red stars, this system diverges from the Johnson (1962) system, despite frequent claims of identity between the two. The Neckel-Chini and Cousins systems, however, are closely comparable. Both of these conclusions were previously reached in a paper by Bessell (1983); fair to good quantitative agreement with his results are obtained. Reddening ratios, the scatter in the Neckel-Chini standard-star data, and the effect of this scatter on published measurements for program stars, are discussed. Transformations from the Neckel-Chini system to the Cousins system are given.
Spectral Analysis of Sound Errors in Persons With Apraxia of Speech and Aphasia

Incorrect productions of [∫] were compared to correct productions of [s] and [∫] in two subjects with apraxia of speech and aphasia. Frequencies of the peak spectral energy (FPSE) were extracted fr...
Measuring contact angles inside of capillary tubes with a tensiometer

We describe a new tensiometry method that allows for determination of wetting inside small diameter tubes or hollow fibers, where the maximum force from the ultimate rise height of liquid is used to estimate advancing contact angles. The technique was first validated with transparent tubes of glass, poly(carbonate) (PC) and poly(tetrafluoroethylene) (PTFE) using four liquids: isopropanol, silicone oil, ethylene glycol and water. Advancing contact angles measured with the tensiometer agreed well with those estimated from final rise height. As this tensiometry technique does not require a view of the liquid, it can be used to measure the wettability inside opaque tubes. We demonstrated this with poly(ether ether ketone) (PEEK) tubes.
In vitro fertilization and public policy: turning to the consumer.

A responsible and comprehensive policy of in vitro fertilization should be preceded by the gathering of empirical information about the application of the procedure in the 138 IVF centers across the country. To date, attention has been directed more to the implications of IVF as a whole than to actual behaviors in the medical community. It is appropriate to survey patients and physicians, examine consent forms, and study guidelines issued by the medical community in order to enhance public knowledge of what has been done voluntarily in the medical community and what remains to be done. Moreover, consumers should be encouraged to speak about their experiences and other groups encouraged to act as advocates for affirmative IVF policy. At present, the interest group spectrum is skewed by physicians' interests groups (speaking for IVF) and other interest groups criticizing the technique. Organized advocates for affirmative IVF policy are less well represented.
Evidence to implicate translation by ribosomes in the mechanism by which nonsense codons reduce the nuclear level of human triosephosphate isomerase mRNA.

Abstract The abundance of the mRNA for human triosephosphate isomerase (TPI) is decreased to 20-30% of normal by frameshift and nonsense mutations that prematurely terminate translation within the first three-quarters of the reading frame. The decrease has been shown to be attributable to a reduced level of TPI mRNA that copurifies with nuclei. Given that the translational reading frame of an mRNA is assessed in the cytoplasm during protein synthesis, cytoplasmic and nuclear RNA processes may be linked. Alternatively, a nuclear mechanism may exist whereby in-frame nonsense codons can be identified. To differentiate between these two possibilities, two distinct modulators of protein synthesis have been tested for the ability to influence the nonsense-codon-mediated reduction in the mRNA level. (i) A suppressor tRNA, which acts in trans to suppress an amber nonsense codon within TPI mRNA, and (ii) a hairpin structure in the 5' untranslated region of TPI mRNA, which acts exclusively in cis to inhibit initiation of TPI mRNA translation, were found, individually, and to a greater extent, together, to abrogate the decrease in mRNA. These results show that tRNA and ribosomes coordinately mediate the effect of a nonsense codon on the level of newly synthesized TPI mRNA. We suggest that the premature termination of TPI mRNA translation in the cytoplasm can reduce the level of TPI mRNA that fractionates with nuclei.
MOMENTS OF UNCERTAINTY: ETHICAL CONSIDERATIONS AND EMERGING CONTAMINANTS.

Science on emerging environmental health threats involves numerous ethical concerns related to scientific uncertainty about conducting, interpreting, communicating, and acting upon research findings, but the connections between ethical decision making and scientific uncertainty are under-studied in sociology. Under conditions of scientific uncertainty, researcher conduct is not fully prescribed by formal ethical codes of conduct, increasing the importance of ethical reflection by researchers, conflicts over research conduct, and reliance on informal ethical standards. This article draws on in-depth interviews with scientists, regulators, activists, industry representatives, and fire safety experts to explore ethical considerations of moments of uncertainty using a case study of flame retardants, chemicals widely used in consumer products with potential negative health and environmental impacts. We focus on the uncertainty that arises in measuring people's exposure to these chemicals through testing of their personal environments or bodies. We identify four sources of ethical concerns relevant to scientific uncertainty: 1) choosing research questions or methods, 2) interpreting scientific results, 3) communicating results to multiple publics, and 4) applying results for policy making. This research offers lessons about professional conduct under conditions of uncertainty, ethical research practice, democratization of scientific knowledge, and science's impact on policy.
Thinking Outside the Box: Residues that Shape the Agonist Binding Site of Nicotinic Acetylcholine Receptors

Nicotinic acetylcholine receptors (nAChRs) are pentameric neurotransmitter-gated ion channels that mediate rapid synaptic transmission throughout the central and peripheral nervous systems. They are well-established targets for small molecule treatments for Alzheimer's disease, schizophrenia, Parkinson's disease, epilepsy, autism, and smoking cessation. To date, 17 human genes have been identified that code for nAChR subunits, termed α1-α10, β1-β4, γ, δ, and e. nAChRs are subdivided into two main categories: the prototypical muscle-type receptor with a precise stoichiometry of (α1)2βδγ (fetal form) and the “neuronal” nAChRs that are formed from various combinations of α2-α10 and β2-β4 subunits. Crystal structures of the acetylcholine binding protein have indicated that various ligands are positioned into a localized binding pocket formed from a cluster of conserved aromatic residues, termed the “aromatic box”. Previous work from our lab has indicated that a common component of the neurotransmitter-binding occurs through the cationic center of the ligand and the face of an aromatic amino acid, termed the cation-π interaction, as well as hydrogen bonding interactions. Together, these binding events cause a change in protein structure permitting ion flow through the channel pore. In the immediate vicinity of the agonist binding site, all nAChR subtypes show identical amino acid compositions, yet significant pharmacological variations are seen. Previous work identified a point mutation, G152K, located near but not directly contributing to the agonist binding site in the α7 nAChR that is critical to agonist potency. Interestingly, this residue is a glycine in the low affinity receptors, such as the muscle-type and α7 nAChRs, but a lysine in the high affinity α4β2 nAChR. Here, we investigate the importance of this residue (G or K) in influencing acetylcholine and nicotine binding interactions in the muscle-type, α7 and α4β2 nAChRs.
High-resolution dosimetry with stimulated phosphorescence.

Thermally stimulated radiophosphorescence has been studied as a means of high‐resolution dosimetry. Small grains of CaSO4:Mn phosphor, embedded in a thin Teflon tape, constitute the dosimeter. The light emitted after irradiation is measured with a photomultiplier coupled to the eyepiece of a scanning microscope. With CaSO4:Mn, the phosphoresence at room temperature is sufficient for measurement after doses in excess of 3000 rads. The spatial resolution of the technique is about 0.2 mm. The method has been tested by measuring the dose distributions from a radium needle and a β‐emitting eye applicator.
Transport-Mediated Synapses in the Retina

Most synapses rely on regulated exocytosis for determining the concentration of transmitter in the synaptic cleft. However, this mechanism may not be universal. Several synapses in the retina appear to use a synaptic machinery in which transmitter transporters play an essential role. Two types of transport-mediated synapses have been proposed. These synapses have been best observed in horizontal cells and cones of nonmammalian retinas. Horizontal cells use a transporter to mediate a bidirectional shuttle, whose balance point is set by ion concentrations and voltage. Nonmammalian cones combine exocytosis and the activity of a transporter. Because exocytosis is voltage independent over most of a cone's physiological voltage range, a voltage-dependent transporter determines the concentration of transmitter in the synaptic cleft. These two synapses may be models for transport-mediated synapses that operate in other parts of the brain.
Modeling relaxation processes in poled electro-optic polymer films

Chielectric spectroscopy, which is frequency-domain electric-field-induced second-harmonic generation, was developed to study the nonlinear optical response near the glass-transition temperature on short time scales. These measurements, along with time-domain second-harmonic generation and time- and frequency-domain dielectric measurements, were used to characterize the decay of poling-induced electro-optic properties of guest–host and side-chain methacrylate polymers that have glass-transition temperatures in the range 90< Tg<125 °C. Time- and frequency-dependent data were fitted with a three-level model. The temperature dependences of the time constants from the polymeric systems were then compared, and a scaling model for predicting useful lifetimes of poled electro-optic media is discussed.
The effects of tension on the absorbance of water into neat and glass‐bead‐filled, cross‐linked polyester

The effects of tension on the absorbance of water at 60°C into neat and glass-bead-filled, cross-linked polyester are reported. Experimental apparatus and procedure to determine water uptake for these materials subjected to three tensile stresses in the range of 0 to 30 percent of the breaking stress of the neat dry polyester are described. It was found, for bead-filled samples, that a load of approximately 4.9 × 106 N/m2 caused the absorption level to increase by 30 percent over that of an unloaded sample. Tensile load was found to have no effect on the absorption characteristics of neat polyester. However, breaking stress was reduced to less than 15 percent of that in the dry neat material. Optical microscope examinations of damage at the fracture surfaces and at the sample cores indicate that the excess moisture uptake in bead-filled samples was not due to microcrack formation.
The role of the multimedia project manager in a changing online world

Traditional project management principles are derived from engineering projects, where many of the details are specified up front. In fact, established project management procedures come from a functional setting, such as engineering, where links between time, design and production are clearly defined. Multimedia project management guidelines, in turn, usually encircle a somewhat more creative path through development and production, leaving room for more richly developed media that takes more time to create. Online multimedia production offers more time for creative idea development, increased prototyping and testing, and a longer time span for changes to be made. The online multimedia production process offers typical phases like planning, design, development, testing, and delivery, but usually manages production in a more open and creative manner - which in turn makes the creation and management of multimedia just a little more difficult from traditional projects. This paper will explore the project management of online multimedia products and how it differs from traditional project management.
Electric poling behavior of polymethylmethacrylate

The electrically stimulated acoustic wave method for observing resident space charge in dielectric insulators has been used to characterize the poling behavior of millimeter-thickness samples of polymethylmethacrylate (PMMA) at temperatures from 40 to 90 degrees C with moderate applied fields. Heterocharge appears in the bulk of every sample tested, resulting in an apparent net increase of low frequency dielectric permittivity over time. In addition, a net internal charge was observed in some cases. This net charge was negative and located in the vicinity of the poling anode, and became most significant at 90 degrees C. >
Compensations for increased rotational inertia during human cutting turns

Locomotion in a complex environment is often not steady state, but unsteady locomotion (stability and maneuverability) is not well understood. We investigated the strategies used by humans to perform sidestep cutting turns when running. Previous studies have argued that because humans have small yaw rotational moments of inertia relative to body mass, deceleratory forces in the initial velocity direction that occur during the turning step, or ‘braking’ forces, could function to prevent body over-rotation during turns. We tested this hypothesis by increasing body rotational inertia and testing whether braking forces during stance decreased. We recorded ground reaction force and body kinematics from seven participants performing 45 deg sidestep cutting turns and straight running at five levels of body rotational inertia, with increases up to fourfold. Contrary to our prediction, braking forces remained consistent at different rotational inertias, facilitated by anticipatory changes to body rotational speed. Increasing inertia revealed that the opposing effects of several turning parameters, including rotation due to symmetrical anterior–posterior forces, result in a system that can compensate for fourfold changes in rotational inertia with less than 50% changes to rotational velocity. These results suggest that in submaximal effort turning, legged systems may be robust to changes in morphological parameters, and that compensations can involve relatively minor adjustments between steps to change initial stance conditions.
Surface electric potentials on worker honeybees leaving and entering the hive.

SummaryWorker honeybees entering and leaving the hive had surface electric potentials that followed a daily rhythm, with a peak at midday or in the early afternoon. Bees entering the hive were normally positively charged, the potential above earth (ground) varying between 0 and +1·5V. Bees leaving the hive had a more uniform potential, normally slightly negative early in the day, becoming slightly positive as the day advanced. The magnitude of all potentials was dependent in part on weather conditions.
Molecular Cloning and Characterization of Glucanase Inhibitor Proteins: Coevolution of a Counterdefense Mechanism by Plant Pathogens

A characteristic plant response to microbial attack is the production of endo-β-1,3-glucanases, which are thought to play an important role in plant defense, either directly, through the degradation of β-1,3/1,6-glucans in the pathogen cell wall, or indirectly, by releasing oligosaccharide elicitors that induce additional plant defenses. We report the sequencing and characterization of a class of proteins, termed glucanase inhibitor proteins (GIPs), that are secreted by the oomycete Phytophthora sojae, a pathogen of soybean, and that specifically inhibit the endoglucanase activity of their plant host. GIPs are homologous with the trypsin class of Ser proteases but are proteolytically nonfunctional because one or more residues of the essential catalytic triad is absent. However, specific structural features are conserved that are characteristic of protein–protein interactions, suggesting a mechanism of action that has not been described previously in plant pathogen studies. We also report the identification of two soybean endoglucanases: EGaseA, which acts as a high-affinity ligand for GIP1; and EGaseB, with which GIP1 does not show any association. In vitro, GIP1 inhibits the EGaseA-mediated release of elicitor-active glucan oligosaccharides from P. sojae cell walls. Furthermore, GIPs and soybean endoglucanases interact in vivo during pathogenesis in soybean roots. GIPs represent a novel counterdefensive weapon used by plant pathogens to suppress a plant defense response and potentially function as important pathogenicity determinants.
Pediatric Antibody Response to Community-Acquired Staphylococcus aureus Infection Is Directed to Panton-Valentine Leukocidin

We examined the antibody responses of pediatric patients infected with community-associated Staphylococcus aureus isolates. The data show that patients infected with Panton-Valentine leukocidin (PVL)-positive strains developed a dominant immunoglobulin G anti-PVL antibody response that correlates with markers of inflammation.
Displacement of DNA‐PKcs from DNA ends by the Werner syndrome protein

The DNA-dependent protein kinase (DNA-PK) complex, which is composed of a DNA-dependent kinase subunit (DNA-PKcs) and the Ku70/80 heterodimer, is involved in DNA double-strand break repair by non-homologous end joining (NHEJ). Ku70/80 interacts with the Werner syndrome protein (WRN) and stimulates WRN exonuclease activity. To investigate a possible function of WRN in NHEJ, we have examined the relationship between DNA-PKcs, Ku and WRN. First, we showed that WRN forms a complex with DNA-PKcs and Ku in solution. Next, we determined whether this complex assembles on DNA ends. Interestingly, the addition of WRN to a Ku:DNA-PKcs:DNA complex results in the displacement of DNA-PKcs from the DNA, indicating that the triple complex WRN:Ku:DNA-PKcs cannot form on DNA ends. The displacement of DNA-PKcs from DNA requires the N- and C-terminal regions of WRN, both of which make direct contact with the Ku70/80 heterodimer. Moreover, exonuclease assays indicate that DNA-PKcs does not protect DNA from the nucleolytic action of WRN. These results suggest that WRN may influence the mechanism by which DNA ends are processed.
THE MECHANISM OF ENZYME-INHIBITOR-SUBSTRATE REACTIONS : ILLUSTRATED BY THE CHOLINESTERASE-PHYSOSTIGMINE-ACETYLCHOLINE SYSTEM.

The mechanism of enzyme-inhibitor-substrate reactions has been analyzed from a theoretical standpoint and illustrated by data from the system cholinesterase-physostigmine-acetylcholine. This treatment is by no means limited to a single system but should be generally applicable to others of similar type. Competitive enzyme-inhibitor-substrate systems show the same characteristic "zones of behavior" already demonstrated for non-competitive systems by Straus and Goldstein. These zones, three in number, determine the mathematical function which relates activity of an enzyme to concentration of an added substrate or inhibitor or both. The effects of suboptimal substrate concentration in such systems have been considered, and the errors arising from various common simplifications of the descriptive equations have been pointed out. The zone behavior phenomenon has been shown to be useful in determining the number of molecules of substrate or inhibitor combining reversibly with a single enzyme center. The kinetics of competitive inhibition, dilution effect, combination of inhibitor or substrate with enzyme, and destruction of inhibitor or substrate by enzyme have been analyzed and experimentally verified, and absolute velocity constants have been determined. Theoretical conclusions have been discussed from the standpoint of their physiological significance. Specifically, it has been shown that: 1. The inhibition of cholinesterase by physostigmine is competitive. A single molecule of physostigmine or acetylcholine combines with one center of cholinesterase-n = 1; and the mechanism n = 2 has been. excluded. Numerical values of the constants for this system are as follows: K(I) = 3.11 x 10(-8)k(1) (combination) = 8.3 x 10(5)k(2) (dissociation) = 0.026 K(S) = 1.25 x 10(-3)k(3) (combination) = 260 k(4) (dissociation) = 0.32 2. No definitive value can be assigned to E, the molar concentration of enzyme centers, but in 4.54 per cent dog serum, E 0.00182; k(D) for acetylcholine destruction is > 3500. There is no reason to assume inhibition of destruction by excess substrate or inhibitor. 7. The common assumption that enzymatic activity follows (or nearly follows) a monomolecular course is true only under limited conditions, which have been here defined. It is not valid, as a rule, for the enzymatic destruction of an inhibitor (e.g., physostigmine) and its application to such a case may lead to erroneous conclusions about the reaction mechanism.
The Telstar experiment

This papers that follow describe in depth the satellite and ground systems designed for the Telstar experiment and give the results to date. The purpose of this introduction is to set the scene in which the project was undertaken and to state some genetal conclusions.
The Shadows and Lights of Waco: Millennialism Today

The Shadows and Lights of Waco: Millennialism Today. James D. Faubion. Princeton: Princeton University Press, 2001.242 pp.
DHA May Prevent Age-Related Dementia

Theriskfordementia,amajorcontributortoincapacitationandinstitutionalization,risesrapidlyasweage,doublingevery5y afterage65.TensofmillionsofnewAlzheimer’sdisease(AD)andotherdementiacasesareprojectedaselderlypopulations increase around the world, creating a projected dementia epidemic for which most nations are not prepared. Thus, there is anurgentneedforpreventionapproachesthataresafe,effective,andaffordable.Thisreviewaddressesthepotentialofone promising candidate, the (n-3) fatty acid docosahexaenoic acid (DHA), which appears to slow pathogenesis of AD and possibly vascular dementia. DHA is pleiotropic, acting at multiple steps to reduce the production of the b-amyloid peptide, widely believed to initiate AD. DHA moderates some of the kinases that hyperphosphorylate the t-protein, a component of the neurofibrillary tangle. DHA may help suppress insulin/neurotrophic factor signaling deficits, neuroinflammation, and oxidative damage that contributeto synaptic loss and neuronal dysfunction in dementia. Finally, DHA increases brain levels of neuroprotective brain-derived neurotrophic factor and reduces the (n-6) fatty acid arachidonate and its prostaglandin metabolitesthathavebeenimplicatedinpromotingAD.ClinicaltrialssuggestthatDHAorfishoilalonecanslowearlystages of progression, but these effects may be apolipoprotein E genotype specific, and larger trials with very early stages are requiredtoproveefficacy.Weadvocateearlyinterventioninaprodromalperiodwithnutrigenomicallydefinedsubjectswith
Education Research: Unsatisfactory NEX rating correlations: Searching for the reasons

Objectives: To determine whether the previously demonstrated poor correlation between local faculty and external American Board of Psychiatry and Neurology (ABPN) examiners evaluating the Neurology Evaluation Exercise (NEX) is attributable to a difference between raters who know the residents and raters who do not, a difference between raters with ABPN experience and raters without it, or some other factor. Methods: Deidentified NEX encounters were videotaped at 2 neurology residency programs. Each video was graded by 1 local faculty examiner, 1 external faculty examiner with ABPN experience, and 1 external faculty examiner without ABPN experience, using the ABPN-sanctioned form. Acceptable/unacceptable rates were compared using Cohen κ statistic. Results: Fifty-eight videotaped NEX encounters involving 20 residents were evaluated by 12 local faculty examiners, 13 ABPN examiners, and 10 external non-ABPN examiners. The level of agreement between groups failed to meet our target κ of 0.7 (ABPN vs non-ABPN external examiners: κ = 0.47 [95% confidence interval 0.21–0.73]; local vs non-ABPN external examiners: κ = 0.37 [95% confidence interval 0.08–0.66]; local vs ABPN external examiners: κ = 0.40 [95% confidence interval 0.14–0.67]). Local, non-ABPN, and ABPN examiners assigned a failing grade to 13 (22%), 11 (19%), and 16 (28%) of the NEX encounters, respectively. Conclusions: The disappointing correlation between local examiners, non-ABPN external examiners, and ABPN external examiners is not solely attributable to bias toward familiar residents. Inadequate training in NEX administration and scoring could be a factor. It is also possible that the NEX is not a valid tool. Further study is necessary.
Microscale hybrid devices powered by biological flagellar motors

We are developing a series of micro hybrid devices based on tethered flagellar motors. Examples of the devices include a microfluidic pump and a micro ac dynamo. The microfluidic pump is realized through the tethering of a harmless strain of Escherichia coli (E. coli) cells to a microelectromechanical-systems-based microchannel. Each E. coli cell is about 3 /spl mu/m long and 1 /spl mu/m in diameter, with several flagella that are driven at the base by molecular rotary motors. The operational principle of the micro pump is based on the viscous pumping effect where continuous rotation of tethered cells in a microfluidic channel forms a fluidic conveyor belt that "drags" fluid from one end of the channel to the other. We used hydrodynamic loading to synchronize cell rotation in order to maximize the fluid pumping capability. The micro dynamo is realized through the integration of tethered flagellar motors with micro ferromagnetic beads and micro copper coils. The micro dynamo generates ac power by using the tethered cells to create a rotating magnetic field around the copper coils. Preliminary results indicate high-power density when compared to other biologically-based micro power generators. Note to Practitioners-The power supply remains a problematic area in the advancement of micro and nanoscale electromechanical systems. Flagellar motors, when tethered in microfluidic devices, provide a unique biological means to supply either mechanical or electrical power to these systems with high-power conversion efficiency. A major advantage of flagellar motor-powered systems is the absence of sophisticated control electronics since the motors are biologically self-sustained, so long as a supply of nutrients is provided to the tethered motors. Additionally, flagellar motors are relatively cost effective; they can be harvested fairly easily from cell growth using established biological protocols. However, integrating flagellar motors with artificial devices is extremely challenging. One of the major obstacles is maintaining the motility of the tethered motors in a microfabricated environment. To overcome this, research work has been focused on optimizing the chemo-mechanical behavior of the motors through genetic engineering and the development of an effective integration scheme for selective motor tethering at designated locations in a microfluidic device.
Techniques and Procedures for Assessing Cognitive Skills

The intent of the article is to survey procedures that could be used to assess progress in instructional programs designed to enhance cognitive skills. The organizational framework is provided by J. R. Anderson’s (1982) theory of cognitive skill development and by Glaser, Lesgold, and Lajoie’s (1985) categorization of dimensions of cognitive skills. After describing Anderson’s theory, the article discusses the following types of measures of cognitive skills: (a) measures of knowledge acquisition, organization, and structure; (b) measures of depth of problem representation; (c) measures of mental models; (d) measures of metacognitive skills; (e) measures of the automaticity of performance; and (f) measures of efficiency of procedures. Each of the sections describing measurement procedures is followed by a discussion of the strengths and weaknesses of the procedures. The article closes with a general discussion of techniques for measuring cognitive skills.
Fc receptor-like activity of mouse hepatitis virus E2 glycoprotein.

The JHM strain of mouse hepatitis virus (MHV-JHM) is a member of the Coronavirus family, which experimentally induces encephalomyelitiS in susceptible mice and rats. In surviving animals a chronic white matter disease ensues. The development of demyelinating lesions is thought to be a primary effect of infection of oligodendrocytes.2, 3 MHV-JHM virus has been shown to persist in the infected brain as long as 1 year after infection. Persistent infections of mice with other strains of MHV such as MHV-A59 and MHV-3 have also been reported.4,5,6 Murine coronaviruses have four structural proteins: a matrix like transmembrane glycoprotein (El), a nucleocapsid protein (N), a peplomer protein (E2), and for some laboratory strains of MHV-JHM a 65,000 Daglycoprotein. 7,8 The E2 glycoprotein (180,000 Da) is responsible for the attachment of MHV to the host cell plasma membrane, induction of cell-to-cell fusion and eliciting of the production of neutralizing antibody. 9,10 In the course of immunological staining of MHV-infected cells with rabbit antisera we observed at moderate dilution (1:50 – 1:100) normal and preimmune serum stained MHV-JHM infected, but not uninfected, cells. This staining could not be removed by absorption of rabbit antiserum with uninfected cells. This observation suggested that infection of cells with MHV may result in the expression of receptors for the Fc region of immunoglobulin G (IgG).
Synthesis of 14(R),15(S)- and 14(s),15(S)-dihydroxy-5,8-z-10,12-E - eicosatetraenoic acid

Abstract 14(4),15(S)- and 14(S),15(S)-dihydroxy-5,8- Z -10,12- E -eicosatetraenoic acids were prepared from 15(S)-HETE by allylic epoxidation and base induced isomerization.
Tick Tock: Time to Recognize the Kidney Clock

A variety of physiologic functions related to the kidney, including BP, GFR, renal blood flow, and urinary sodium excretion, exhibit a circadian pattern of variation (reviewed by Stow and Gumz[1][1]). Whereas these clinical observations are well established, the underlying molecular mechanisms are