cssi/SciSciGPT-SciSciNet huggingface dataset:
A quick and gentle method for mounting crystals in capillaries

The capillary mounting of protein crystals is still necessary under some circumstances, despite its being supplanted by loop mounting/flash freezing as the favored method for crystal mounting prior to data collection. Traditional capillary mounting methods require a degree of dexterity and finesse that causes apprehension among many crystallographers. Here a simple method for capillary mounting that uses a loop for depositing the crystal in the capillary is described.
Essential amino acid methyl esters : Major sex pheromone components of the cranberry white grub, Phyllophaga anxia (Coleoptera : Scarabaeidae)

Chiral capillary gas chromatographic–electroantennographic detection (GC-EAD) analysis indicates that L-valine and L-isoleucine methyl esters are the major sex pheromone components released by females of the cranberry white grub, Phyllophaga anxia (LeConte). The GC retention times and GC-mass spectrometry of the two natural compounds were identical to those of authentic standards. Of five reproducible GC-EAD active components revealed with female volatiles, the L-valine and L-isoleucine methyl esters elicited the strongest male antennal responses. The ratio of L-valine and L-isoleucine methyl esters was determined to be 3:1 by analysis of pheromone gland extracts. Chirality was shown to be critical by GC-EAD, since only the L-form of these amino acid methyl esters elicited an EAD response. In field experiments conducted in Massachusetts, a synthetic 3:1 blend of L-valine and L-isoleucine methyl esters on a rubber septum was attractive to P. anxia males.
Time dependent properties of bovine meniscal attachments: stress relaxation and creep.

It has been suggested that the success of a meniscal replacement is dependent on several factors, one of which is the secure fixation and firm attachment of the replacement to the tibial plateau [Chen, M.I., Branch, T.P., et al., 1996. Is it important to secure the horns during lateral meniscal transplantation? A cadaveric study. Arthroscopy 12(2), 174-181; Alhalki, M.M., et al., 1999. How three methods for fixing a medial meniscal autograft affect tibial contact mechanics. American Journal of Sports Medicine 27(3), 320-328; Haut Donahue, T.L., et al., 2003. How the stiffness of meniscal attachments and meniscal material properties affect tibio-femoral contact pressure computed using a validated finite element model of the human knee joint. Journal of Biomechanics 36(1), 19-34]. The complex loading environment in the knee lends itself to different loading environments for each meniscal attachment. We hypothesize that the creep and stress relaxation characteristics of the horn attachments will be different for the anterior versus posterior, and medial versus lateral attachments. To test this hypothesis, the stress relaxation and creep characteristics of the meniscal horn attachments were determined. The stress relaxation properties of load/stress at the end of the test, and the load/stress relaxation rate demonstrated no significant statistical differences between the attachments. Unlike the stress relaxation properties, the creep properties demonstrated some significant differences amongst the attachments. The normalized displacement at the end of the test, normalized creep rate and strain creep rate for the lateral anterior attachment were significantly different than those of the medial posterior attachment (p 0.05). The time dependent properties obtained in this experiment provide insight into the behavior of meniscal horn attachments under various loading situations. The results indicate that a suitable meniscal replacement may require different properties for the lateral and medial horns.
SCAN: A Case-Based Reasoning Model for Generating Information System Control Recommendations

This paper describes SCAN, a case-based reasoning model for generating information system control recommendations. The purpose of the paper is to explain how a case-based reasoner may be used to support inexperienced information system auditors in evaluating controls and proposing audit recommendations. As a case-based reasoner, SCAN functions by reasoning by analogy to similar past cases. SCAN models audit experience as traces of past cases which are stored in a case knowledge base. In addition to a database of past audit cases, SCAN consists of indices for storing and retrieving cases, a similarity metric for measuring case similarity, and rules for using similar cases to generate control recommendations. SCAN uses past cases to remind the user of previous control failures, to set expectations about case features and controls, to use as a pattern against which to compare a client's controls and to help justify or explain its recommendations. SCAN's recommendations were judged to be more like those of an experienced auditor than either a student or a textbook model.
Determinants by definition

We give a diagrammatic expansion of n by n determinants from the definition. We define d‐permutations and use these to obtain matrices which are expanded by using appropriate signs. Then the determinant is obtained by summing these expanded matrices. The appropriate signs are then explained for different n.
Power beaming providing a space power infrastructure

A study based on two levels of technology maturity, which applies to the power beaming concept to four planned satellite constellations, is described. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations to orbits ranging from low-Earth orbit to geosynchronous orbit. Two constellations, a space surveillance and tracking system and space-based radar, can be supported with current technology. The other two constellations, a space-based laser array and a boost surveillance and tracking system, will require power and transmission system improvements before their break-even specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20% would meet or exceed break-even for these constellations. >
AXAF high-resolution camera (HRC): the challenge of calibration

The High Resolution Camera (HRC) is a microchannel plate based, photon counting, imaging detector for the Advanced X- ray Astrophysics Facility (AXAF) that will be placed in a high earth orbit scheduled for launch in December, 1998. An end-to-end calibration of the HRC and the AXAF High Resolution Mirror Assembly was carried out at the Marshall Space Flight Center's X-ray Calibration Facility. This activity was preceded by various subsystems level calibrations of the detector components, but only through complete end-to-end testing was it possible to fully study the instrument and identify areas for improvement. As a result, several modifications were made to the HRC. These were followed by a series of flat field calibrations used to 'correct' the end-to-end results for flight.
Structural Insight into Proteorhodopsin Oligomers

Oligomerization has important functional implications for many membrane proteins. However, obtaining structural insight into oligomeric assemblies is challenging, as they are large and resist crystallization. We focus on proteorhodopsin (PR), a protein with seven transmembrane α-helices that was found to assemble to hexamers in densely packed lipid membrane, or detergent-solubilized environments. Yet, the structural organization and the subunit interface of these PR oligomers were unknown. We used site-directed spin-labeling together with electron spin-resonance lineshape and Overhauser dynamic nuclear polarization analysis to construct a model for the specific orientation of PR subunits within the hexameric complex. We found intersubunit distances to average 16 A between neighboring 55 residues and that residues 177 are >20 A apart from each other. These distance constraints show that PR has a defined and radial orientation within a hexamer, with the 55-site of the A-B loop facing the hexamer core and the 177-site of the E-F loop facing the hexamer exterior. Dynamic nuclear polarization measurements of the local solvent dynamics complement the electron spin-resonance-based distance analysis, by resolving whether protein surfaces at positions 55, 58, and 177 are exposed to solvent, or covered by protein-protein or protein-detergent contacts.
Amplified cellular oncogenes in neoplasms of the human central nervous system

Significant advances have recently been made in a number of areas concerning central nervous system (CNS) neoplasia. Particularly salient are the following: (1) gene amplification is related to increasing grade of human glioma malignancy and occurs in approximately 40% of the most common and most malignant variety of glioma, glioblastoma multiforme (GBM), (2) by far the most commonly amplified gene in glioblastomas is the epidermal growth factor receptor (EGFR) gene, which is amplified in about one third of GBMs, (3) a small percentage of GBMs amplify N-myc or the novel sequence gli, (4) the EGFR gene is rearranged in at least half of gliomas in which it is amplified, and (5) EGFR gene rearrangement results in external domain deletions that yield truncated EGF receptors. Antibodies specific for the mutant EGF receptor fusion junction have been successfully produced and provide stimulating new potential avenues for tumor imaging and therapy. For pediatric CNS neoplasms, only medulloblastoma has been investigated in adequate numbers; a small percentage exhibit amplification of either the N-myc or c-myc genes.
Electro-optical characterization of n-CdS nanowires/p-CdTe heterojunction solar cell devices

Arrays of 100 nm long n-cadmium sulfide (CdS) nanowires were investigated as window layers for solar cells. These arrays exhibited enhanced transmission especially for wavelengths below 512 nm. Next, films of CdTe were deposited by CSS and the solar cell devices completed. I-V and C-V characteristics were measured in the temperature range of 100–300 °K. Analysis indicated that interface recombination and tunneling played dominant roles in electron transport across the heterojunction. The highest power conversion efficiency (PCE) nanowire cell to date had V oc , J sc , FF and PCE values of 766 mV, 25 mA/cm2, 58% and 11.1% respectively.
EVALUATION OF MONOSACCHARIDES, DISACCHARIDES AND CORN SYRUPS AS DISPERSANTS FOR HEAT‐PROCESSED DRIED SOY MILK PROTEINS

— Addition of carbohydrates such as dextrose, sucrose or corn syrups to heat-treated soy milk before drying significantly improved the redispersibilities of the resultant dried products, reaching about 100% at 1.0–1.5 times as much sugar as soy milk solids. Among carbohydrates tested, corn syrups, expecially those enzyme-converted in the region of 48.5 D.E., seemed to be suitable materials because of high dispersant efficiency, moderate sweetness and easier drying. One possible reason for the dispersant effects of sugars is suggested to be a physical separation of soy protein molecules. Effects of corn syrups upon the spray-drying of soy milk also are discussed.
Toughness, trees, and walks

A graph is t-tough if the number of components of G\S is at most |S|-t for every cutset S ⊆ V (G). A k-walk in a graph is a spanning closed walk using each vertex at most k times. When k = 1, a 1-walk is a Hamilton cycle, and a longstanding conjecture by Chvatal is that every sufficiently tough graph has a 1-walk. When k ≥ 3, Jackson and Wormald used a result of Win to show that every sufficiently tough graph has a k-walk. We fill in the gap between k = 1 and k ≥ 3 by showing that, when k = 2, every sufficiently tough (specifically, 4-tough) graph has a 2-walk. To do this we first provide a new proof for and generalize a result by Win on the existence of a k-tree, a spanning tree with every vertex of degree at most k. We also provide new examples of tough graphs with no k-walk for k ≥ 2. © 2000 John Wiley & Sons, Inc. J Graph Theory 33:125137, 2000
Configuring the Field of Play: How Hosting the Olympic Games Impacts Civic Community

I theorize and empirically illustrate how the mega-event of the Olympic Games configures relational and symbolic systems within the host city. I focus on a field at the level of the local geographic community and explore how city character and traditions enable both persistence and change in institutional elements even when potentially disruptive events occur. I present two exploratory studies. The first shows how the event of the Olympics is rooted in the local field of the host city but varies by communities; the second explores the dynamics of configuring the field of one Olympic city: Atlanta, host of the 1996 Olympic Games.
New Photoresponses of Phycomyces

The influence of light on asexual fruiting and mycelial growth of Phycomyces blakesleeanus Burgeff was studied by means of fruiting body counts and size measurements in cultures on solid media under varied incubation conditions. Five types of photoresponses were shown by ATCC Strain 8743a: (a) photoinduction of giant sporangiophores; (b) interference by light with an endogenous system that otherwise induces fruiting when the mycelium approaches the rim of the Petri dish; (c) inhibition of mycelial growth rates by light; (d) inhibition of dwarf sporangiophore induction by light; and (e) postponement by light of death in clones maintained by serial transfer at low temperature. A second strain, designated G5, showed responses comparable to (a), (b), and (d). The magnitudes of the responses were greatly affected by temperature of incubation and available nitrogen (asparagine) supply. The photoinduction of giant sporangiophores could be demonstrated with light of wavelengths between 380 and 480 nanometers but not with 520 nanometers or above. At 480 nanometers, light doses as small as 40 ergs per square centimeter were effective in inducing giant sporangiophores in strain 8743a.
Accurate measure of laser irradiance threshold for near-infrared photo-oxidation with a modified confocal microscope.

Summary Femtosecond mode-locked lasers are now being used routinely in multiphoton fluorescence and autofluorescence spectroscopy, are just beginning to be used in refractive surgery, and may be used in the future diagnosis of skin cancer. Pulses from these lasers induce non-linear effects in resultant tissue interactions. Using a modified confocal microscope with dispersion compensation and accurate measurements of beam diameter, a very low threshold was measured for photochemical oxidation in cultured cells. The measured threshold showed non-linear photo-oxidation at a peak irradiance and photon-flux density of 8.4 × 108 W cm−2 and 3.4 × 1027 photons cm−2 s−1, respectively (90-fs pulse). The impact of these findings is significant to those using ultrashort lasers because they provide a tangible reference point (microscope-independent) for the generation of photo-oxidative stress in laser-exposed tissues, and because they highlight the importance of dispersion compensation in minimizing collateral tissue damage.
Moving contact lines and Langmuir–Blodgett film deposition

The objective of this paper is to point out the close relationship between contact line dynamics and LB film depositions, and it is designed to serve as a blueprint for future analysis of the LB technique. Moving contact lines and contact angles play a major role in Langmuir-Blodgett ultrathin film depositions. Although the effect of contact angles has been recognized for many years, a fundamental and comprehensive explanation of the phenomena taking place at the contact line has not been formulated before. Our understanding of contact line dynamics has improved thanks to careful experiments and new theoretical developments. Flow patterns depend on dynamic contact angle and the ratio of viscosities of the gas and liquid phases. More recently dynamic contact angles-and flow patterns-have been linked to forces of molecular and double-layer origin. The dynamic relationship of flow patterns to interfacial and transport properties can be used to explain seemingly contradictory experimental results reported by researchers during more than 60 years of experience with the L-B technique. Windows of operability can be defined for X-type and Z-type depositions that are useful in the design of experimental and industrial L-B deposition equipment.
Variation in plasma oestrogens and androgens during the seasonal and semilunar spawning cycles of female gulf killifish, Fundulus grandis (Baird and Girard)

Variations in 17β-oestradiol, oestrone, testosterone, and 11-ketotestosterone were measured by radioimmunoassay in the plasma of female Gulf killifish, Fundulus grandis, during their seasonal and semilunar spawning cycles. Both 17β-oestradiol and testosterone exhibited distinct seasonal variation, peaking very early in the breeding season during March and April, decreasing gradually thereafter the cessation of spawning in late August and the seasonal regression of ovaries in September, and eventually falling below the detectable limits of our assays during the very early stages of seasonal ovarian recrudescence in November. Both steroids also exhibited distinct semilunar variation within the breeding season, with highest plasma concentrations immediately prior to, and during, each spring tide spawning. Such results suggest that these steroids have physiological roles in the generation and regulation of both seasonal and semilunar reproductive cycles: 17β-oestradiol by controlling development of vitellogenic oocytes; testosterone perhaps by acting as a precursor in the production of oestrogens and other steroids. In contrast, oestrone and 11-ketotestosterone were only rarely detected, implying that these particular oestrogens and androgens are probably not physiologically active in female killifish.
Efficacy and utilization of skin-to-skin care in the NICU

Abstract Research to date suggests that kangaroo care, or skin-to-skin care, is safe and therapeutic for the infant and the parent. A review of the kangaroo/skin-to-skin care research found that the practice is safe and has many positive outcomes. This article closely examines recent research results. It compares and contrasts the strengths and weaknesses in the sampling, methodology, and outcomes of the studies. Recommendations for implementation in the neonatal intensive care unit are made and goals for future research areas are identified. Copyright 2002, Elsevier Science (USA). All rights reserved.
Lattice codes based on product constructions over F 2 q with applications to compute-and-forward

A novel construction of lattices is proposed. This construction can be thought of as Construction A with linear codes that can be represented as the Cartesian product of two linear codes over F q ; hence, is referred to as the product construction. The existence of a sequence of Poltyrev-good lattices generated by the product construction under some conditions is shown. This family of lattices is then used to generate signal constellations with q2 elements which can be used in conjunction with multilevel coding with channel codes over F q instead of F q2 to design good coded modulation schemes for compute-and-forward.
A Long-Term History of Drought Occurrence in Western United States as Inferred from Tree Rings

(1975). A Long-Term History of Drought Occurrence in Western United States as Inferred from Tree Rings. Weatherwise: Vol. 28, No. 6, pp. 244-249.
Ethical dilemmas in family therapy.

A review of the literature in the area of ethical dilemmas facing family therapists revealed that there were a number of issues facing family therapists which are not included in the Principles for Family Therapists (1984) of the American Association for Marriage and Family Therapy. Seventy-five family therapists from across the nation responded to a questionnaire which asked what ethical dilemmas they face and how helpful the ethical guidelines are with these dilemmas. Results indicate that family therapists are encountering dilemmas which are not included in the Principles, significantly more often than those that are included. The ethical principles were found to be helpful for those ethical dilemmas attended to by the Principles.
Synthesis and structural characterization of complexes derived from treatment of gallium trichloride with 3,5-diphenylpyrazole

Abstract The adduct GaCl3(Ph2pzH) (Ph2pzH, 3,5-diphenylpyrazole) was synthesized in 96% yield upon treatment of equimolar amounts of gallium trichloride with Ph2pzH in toluene at room temperature. The tetrachlorogallate salt [Ph2pzH2]+GaCl4 − was obtained in 93% yield by treatment of a 2:1 stoichiometry of gallium trichloride and Ph2pzH at room temperature, followed by recrystallization from toluene/dichloromethane. The X-ray crystal structures of GaCl3(Ph2pzH) and [Ph2pzH2]+GaCl4 − were determined, and reveal weak hydrogen bond interactions between the nitrogen-bound hydrogen atoms and gallium-bound chlorine atoms. Examination of the formation of [Ph2pzH2]+GaCl4− from GaCl3(Ph2pzH) and gallium trichloride (1.0 equiv.) revealed that the hydrogen chloride used to form [Ph2pzH2]+GaCl4− arises from gallium trichloride-catalyzed chloromethylation of toluene. Under conditions where [Ph2pzH2]+GaCl4 − was isolated in 82% yield upon treatment of GaCl3(Ph2pzH) and gallium trichloride (1.0 equiv.) in toluene/dichloromethane, a mixture of ditolylmethane isomers was isolated in 330% yield based upon gallium trichloride.
Dimensional characteristics of uncomplicated autopsy-retrieved acetabular polyethylene liners by ultrasound

A new, in vitro ultrasound-based method to measure the thickness of acetabular polyethylene components was developed and applied to 26 uncomplicated autopsy-retrieved components and 40 unused components. The average age at total hip arthroplasty was 62 years and the average time in service of the retrieved components was 49 months. The clinical notes indicated that each of the arthroplasties was functioning well at the time of the patients death. Thickness distributions in the retrieved components had two distinct patterns. Eighteen of the retrieved components (69%) had their thinnest areas self-contained and located near the polar point. In the other 8 retrieved components (31%) the areas of minimum thickness were adjacent to the rim. Thickness distribution in the unused cups was predominately concentric with the thinnest area located near the polar point (85% of the cups). Detection limits for dimensional change were established based on the variability found in the unused liners. Fifteen of the 26 retrieved components (58%) had areas of reduced thickness which exceeded the detection limits; the average thickness reduction rate for these components was 0.076 mm per year. The other 11 retrieved components (42%) lacked such areas. The 15 cups with areas of reduced thickness had a longer time in service (63 ± 18 months) than the 11 cups without areas of reduced thickness (32 ± 25 months) (p = 0.003), but no other clinical factor (age, gender, Harris hip score, size and inclination of the cup, type of femoral fixation) was associated with these 15 cups. Cylindrical models to estimate volumetric change tended to underestimate the actual changes, suggesting that the actual particulate burden may be greater than previously appreciated. Finding that the pattern of thickness reduction can vary suggests that distinctive hip loading modes may be present postoperatively in patients with total hip arthroplasty. The wear rates of these components are consistent with wear rates calculated from radiographic data for well-functioning implants and are considerably lower than wear rates calculated for surgically-retrieved implants, indicating that autopsy-derived retrievals may be more representative of the majority of components currently in service than surgically-derived retrievals. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 120–129, 1998.
Chemotherapeutic inhibition of supragingival dental plaque and gingivitis development

A 6-month double-blind, controlled clinical study was conducted on 107 healthy adult subjects to determine the efficacy of a mouthrinse used as a supplement to regular oral hygiene measures on supragingival dental plaque and gingivitis. 115 healthy adult patients were recruited for the study. Following screening examinations for minimal entry levels of existing gingivitis and plaque in patients with a minimum of 20 sound natural teeth, extrinsic tooth stain, gingivitis and plaque index scores were recorded. Soft tissues were evaluated. All subjects then received a complete dental prophylaxis, removing plaque, calculus and extrinsic stain. Utilizing their normal oral hygiene, subjects began a regimen of rinsing with 20 ml of the randomly assigned rinse, twice daily for 30 s for 6 months. 7 days after prophylaxis, gingivitis was again scored (baseline 2). Soft tissue, gingivitis, plaque area and extrinsic stain were evaluated again at 3 and 6 months. Results demonstrated that after 6 months, listerine produced a 34% inhibition of both plaque and of gingivitis compared to a hydroalcohol control (p less than 0.001).
Proposed solution to the FROC problem and an invitation to collaborate

There is a need to develop observer performance methodologies that are not restricted to binary tasks, as is the widely used Receiver Operating Characteristic (ROC) method. Clinical tasks involving lesion localization do not fit the ROC paradigm. Alternative approaches namely Free-response ROC (FROC) and Localization ROC (LROC), have their own limitations. They neglect intra-image correlations, with consequent questionable statistical validity, the image scoring criterion is arbitrary and affects the results, and they do not account for the two sub-tasks, namely detection and localization, inherent to these experiments. The purpose of this work is to propose a new FROC model that deals with these issues, to propose a maximum likelihood method of estimating the model parameters, and to invite collaboration by others in implementing the solution. The model was used to generate simulated FROC data that illustrate the above-mentioned limitations. Measures of detection and localization performance are proposed that will allow FROC performance to be interpreted more quantitatively, and observer performance experiments to be conducted with greater statistical power.
The Hood River Issei: An Oral History of Japanese Settlers in Oregon's Hood River Valley

Gathers oral histories from Japanese immigrants, most of them women, that discuss leaving Japan, life as farmers and orchard workers, and the World War II relocation.
Intravenously administered cell-permeant calcium buffer decreases evoked synaptic potentials in rat dentate gyrus in vivo

We examined the effects of the neuroprotective cell-permeant Ca2+ buffer, 2-aminophenol-N,N,O-triacetic acid acetoxymethyl ester (APTRA-AM, 20-40 mg/kg), on synaptically evoked potentials in the dentate gyrus of awake rats. Intravenous APTRA-AM (20 mg/kg) decreased the evoked potentials with peak effects approximately 6 h after infusion, and recovery to control levels by 24 h. Peak decrease in the population spike (PS) amplitude was by 72+/-17% of control, and the excitatory postsynaptic potential (EPSP) slope was decreased by 31+/-12%. APTRA-AM (40 mg/kg), decreased the PS amplitude and EPSP slope by 58+/-7% and 31+/-6% of pre-drug levels, respectively. These effects were qualitatively similar to the presynaptically mediated decreases in synaptic potentials previously demonstrated in vitro with APTRA-AM. These results indicate that the cell-permeant Ca2+ buffer, APTRA-AM, attenuates hippocampal excitability in vivo, most likely by decreasing synaptic neurotransmission.
A comment on the acceleration of charged particles in the presence of micro-turbulence as related to solar flares

In this note we clarify the conditions in which charged particles may be accelerated by a DC electric field in the presence of plasma micro-turbulence.
Places in spaces: common ground in virtual worlds

Virtual worlds can allow conversational participants to achieve common ground in situations where the information volume and need for clarification is low. We argue in favor of this assertion through an examination of a semi-structured activity among hundreds of users held in a virtual world. Through the idea of 'implicit grounding', we argue that the affordances of contextualized space can allow users to achieve common ground in a low information volume, low clarification need activity. We use the success of the event to re-examine and extend Clark and Brennan's work on grounding in communication.
Abnormalities in rapid, automatic aspects of attention in schizophrenia: blunted inhibition of return

When a visual cue is presented at the same location but 100 ms prior to presentation of a visual stimulus, reaction time to the stimulus is decreased. However, in healthy subjects if the interval between the cue and the stimulus is between 500 and 1500 ms, reaction time is increased (‘inhibition of return’). The present experiment compared inhibition of return in 11 medicated and clinically stable schizophrenic outpatients and 11 healthy control subjects screened by SADS-L. Healthy subjects responded faster to true cues than false cues when the interval between cue and stimulus was 100 ms, but responded equally fast in the two conditions with a 200 ms interval and responded faster to false than true cues at 700 and 1200 ms intervals. Schizophrenics, in contrast, responded faster to true than false cues at both 100 and 200 ms intervals and showed lower than normal advantages on false as compared to true cues at 700 and 1200 ms intervals (group × cue type × interval interaction p < 0.01). Thus while schizophrenics showed ‘inhibition of return’ it did not begin until greater than normal intervals between cue and stimulus and was blunted in magnitude. This suggests failure of inhibitory mechanisms that are important in very rapid and automatic aspects of normal attention.
Localization of receptors in lipid rafts can inhibit signal transduction

Processes of cell survival, division, differentiation, and death are guided by the binding of signal molecules to receptors, which activates intracellular signaling networks and ultimately elicits genetic, biochemical, or biomechanical responses within the cell. While intracellular mechanisms for these processes have been well studied, little attention has been given to the role extracellular ligand transport and binding may play in signal initiation. Recent studies have found that the localization of receptors in lipid rafts is critical for the functions of many signaling pathways. By concentrating membrane components, rafts may promote essential interactions for signaling. Lipid rafts can also have negative effects on signaling, but mechanisms remain elusive. We propose that raft-mediated receptor clustering can reduce signaling by prolonging the diffusion of ligands to their receptors. We quantify this effect using a simple diffusion-limited binding model that accounts for the spatial distribution of lipid rafts and receptors on the cell surface. We find that receptor clustering can reduce the apparent rate of receptor binding by up to 80%, consistent with observed increases in epidermal growth factor (EGF) binding by up to 100% following disruption of lipid rafts (Pike and Casey 2002 Biochemistry 41:10315-10322; Roepstorff et al. 2002 J Biol Chem 277:18954-18960). Failure to account for the effects of receptor clustering on rates of ligand binding can skew the interpretation of current methods of cancer diagnosis and treatment. Finally, we discuss how the activation of particular signaling pathways can change over time, depending, in part, on the overall level and spatial distribution of the receptors.
TU-SAMS-332-01: Film-Screen Mammography QA: What You Need to Know

The medical physicist provides a valuable service to mammography facilities by helping to ensure the production of high quality images at a low radiation dose. This presentation will describe the role of the medical physicist in mammography QA and equipment performance evaluation of film‐screen systems. Individual tests for both initial and annual equipment evaluations will be described. Special attention will be paid to potential pitfalls, common problems and ways to increase efficiency of the testing process. Educational Objectives 1. Review medical physicist responsibilities in film‐screen mammography QA. 2. Learn about the specific requirements involved in testing for new equipment installations. 3. Review quality control procedures for annual equipment performance evaluations. 4. Learn about ways to streamline equipment performance evaluations.
Time series analysis of local fluctuations in traffic parameters

Abstract This paper considers the problem of constructing a dynamic time series model for local fluctuations in traffic parameters from observations collected during periods when the rate of traffic flow is not constant application of linear high-pass filters to serially correlated data obtained through a measurement queue is considered in both the time and frequency domains. For the filtered series, a general autoregressive moving average model is postulated to describe the local fluctuations. Throughout the paper, an eight-hour sample of air traffic in the local control sector at New York's LaGuardia Airport serves as a case study for the techniques described.
Initiatives for Improving Out-of-Hospital Cardiac Arrest Outcomes

Out-of-hospital cardiac arrest (OHCA) leading to sudden cardiac death (SCD) remains a huge public health burden, accounting for >350 000 deaths in the United States each year1 and an equivalent number in Europe. The societal impact is evident from the fact that as many as 50% of all cardiac deaths are SCDs,1 with many of the affected individuals in their productive years. One cost estimate places the financial burden on society at $33 billion per year in the United States,2 including the cost of response systems, post–cardiac arrest hospitalizations, and long-term care of survivors. Long-term care includes rehabilitation, disability expenses, and medical costs specific to survivors such as implantable cardioverter-defibrillators. Article see p 1859 Attempts to address the OHCA/SCD challenge encompass 3 basic strategies: prediction, prevention, and intervention. Prediction remains a daunting challenge because 50% of SCDs are first cardiac events without specific forewarnings of unrecognized disease.1,3,4 Data on familial clustering of SCD as first cardiac events4 suggest the possibility of genetic profiling of individual risk. However, other than the rare inherited arrhythmia syndromes, identification of genetic SCD risk markers with a large effect size remains a hope for the future. The numerically large problem associated with the common cardiac disorders dominates the public health burden. Atherosclerosis risk scoring methods provide some profiling capability for this most common cause, but they are largely not specific for cardiac arrest itself and have limitations for individual risk prediction.3 Prevention is equally challenging. It depends on unrealized strategies for developing individual risk prediction models having small denominators and proportionally large numerators, in addition to cost-effective preventive therapies that provide high levels of efficiency. The latter is defined as high absolute risk reduction in an identified population subset that encompasses a substantial proportion of the …
The molecular chaperone DnaJ is required for the degradation of a soluble abnormal protein in Escherichia coli.

In addition to promoting protein folding and translocation, molecular chaperones of Hsp70/DnaJ families are essential for the selective breakdown of many unfolded proteins. It has been proposed that chaperones function in degradation to maintain the substrates in a soluble form. In Escherichia coli, a nonsecreted alkaline phosphatase mutant that lacks its signal sequence (PhoAΔ2–22) fails to fold in the cytosol and is rapidly degraded at 37 °C. We show that PhoAΔ2–22 is degraded by two ATP-dependent proteases, La (Lon) and ClpAP, and breakdown by both is blocked in a dnaJ259-ts mutant at 37 °C. Both proteases could be immunoprecipitated with PhoA, but to a much lesser extent in the dnaJ mutant. Therefore, DnaJ appears to promote formation of protease-substrate complexes. DnaJ could be coimmunoprecipitated with PhoA, and the extent of this association directly correlated with its rate of degradation. Although PhoA was not degraded when DnaJ was inactivated, 50% or more of the PhoA remained soluble. PhoA breakdown and solubility did not require ClpB. PhoA degradation was reduced in a thioredoxin-reductase mutant (trxB), which allowed PhoAΔ2–22 to fold into an active form in the cytosol. Introduction of thednaJ mutation into trxB cells further stabilized PhoA, increased enzyme activity, and left PhoA completely soluble. Thus, DnaJ, although not necessary for folding (or preventing PhoA aggregation), is required for PhoA degradation and must play an active role in this process beyond maintaining the substrate in a soluble form.
Using Error Equivalence Concept to Automatically Adjust Discrete Manufacturing Processes for Dimensional Variation Control

Traditional statistical process control (SPC) has been widely employed for the process monitoring in discrete part manufacturing. However, SPC does not consider any adjustment preventing the process drift. Furthermore, many in-line adjustment approaches, such as thermal error compensation and avoidance, are designed only for machine tool error reduction. This paper intends to fully utilize the engineering process information and to propose an alternative compensation strategy based on equivalent fixture error (EFE) concept that could reduce overall effect of the process errors. Considering three types of error sources in a machining process, we propose to adjust fixture locators to compensate errors using the EFE model. The dynamic property of EFE is investigated for the feedback adjustment of both static and quasi-static errors in machining processes. A minimum-mean-square-error controller is designed based on the dynamic EFE model. We then evaluate the performance of the controller such as stability and sensitivity. A selfupdating algorithm for the controller will track the latest process information to stabilize the controller output. Finally, we simulate this process adjustment using the data collected from a real machining process. The results show that this algorithm can improve the machining quality. DOI: 10.1115/1.2714581
Resilient metal spring network silicone-matrix composite for separable interconnections

Resilient metal spring silicone-matrix conducting composites for separable interconnections in electronics were fabricated by the impregnation of silicone into a preform comprising randomly oriented C-shaped Cu-Be springs and a small proportion of Sn-Pb solder, which served to connect the springs at some of their intersections. Composites containing 6.1-9.8 vol.% total filler exhibited volume electrical resistivity 0.5-1.0 mΩ.cm and contact resistivity (with copper) 11-17 mΩ.cm2. A compressive stress of about 30 kPa was needed for the low contact resistivity to be reached. The volume 17-26% and the contact resistivity increased by 5% after heating in air at 130-150°C for seven days. Composites containing <9 vol.% total filler showed no stress relaxation for seven days at 6.0% strain.
Granitic pegmatites as estimators of crustal pressures; a test in the eastern Adirondacks, New York

Liquidus equilibria of the “granitic” system (Q-Or-Ab-An-H2O) provide a potential means of estimating pressures and temperatures in natural rocks if certain requirements are met. These include limitations on bulk composition and mineralogy and a basis for a presumption of fluid-phase saturation of the former melt. A test of application of the experimental data is possible by means of at least two approaches. In this paper we show that an estimate of 7 kb obtained from a cross-cutting granite pegmatite in the eastern Adirondacks, New York, compares favorably with the results of other studies of similar granulite-facies metamorphism.
Beyond Parkinson disease: Amyotrophic lateral sclerosis and the Axon guidance pathway

Background We recently described a genomic pathway approach to study complex diseases. We demonstrated that models constructed using single nucleotide polymorphisms (SNPs) within axon guidance pathway genes were highly predictive of Parkinson disease (PD) susceptibility, survival free of PD, and age at onset of PD within two independent whole-genome association datasets. We also demonstrated that several axon guidance pathway genes represented by SNPs within our final models were differentially expressed in PD. Methodology/principal findings Here we employed our genomic pathway approach to analyze data from a whole-genome association dataset of amyotrophic lateral sclerosis (ALS); and demonstrated that models constructed using SNPs within axon guidance pathway genes were highly predictive of ALS susceptibility (odds ratio = 1739.73, p = 2.92x10(-60)), survival free of ALS (hazards ratio = 149.80, p = 1.25x10(-74)), and age at onset of ALS (R(2) = 0.86, p = 5.96x10(-66)). We also extended our analyses of a whole-genome association dataset of PD, which shared 320,202 genomic SNPs in common with the whole-genome association dataset of ALS. We compared for ALS and PD the genes represented by SNPs in the final models for susceptibility, survival free of disease, and age at onset of disease and noted that 52.2%, 37.8%, and 34.9% of the genes were shared respectively. Conclusions/significance Our findings for the axon guidance pathway and ALS have prior biological plausibility, overlap partially with PD, and may provide important insight into the causes of these and related neurodegenerative disorders.
Spreading dynamics on small-world networks with connectivity fluctuations and correlations

Infectious diseases and computer malwares spread among humans and computers through the network of contacts among them. These networks are characterized by wide connectivity fluctuations, connectivity correlations, and the small-world property. In a previous work [Phys. Rev. Lett. 96, 038702 (2006)] I have shown that the connectivity fluctuations together with the small-world property lead to a spreading law characterized by an initial power law growth with an exponent determined by the average node distance on the network. Here I extend these results to consider the influence of connectivity correlations which are generally observed in real networks. I show that assortative and disassortative connectivity correlations enhance and diminish, respectively, the range of validity of this spreading law. As a corollary I obtain the region of connectivity fluctuations and degree correlations characterized by the absence of an epidemic threshold. These results are relevant for the spreading of infectious diseases, rumors, and information among humans and the spreading of computer viruses, email worms, and hoaxes among computer users.
Honduran boys confronting adversity: urban multi-locality and kin mobilization

This article describes ethnographic research involving street children and child labor in urban Honduras. It is set in a context of deteriorating social, political, and economic conditions that has created an increase in child labor. However, the research findings have delineated that a growing number of children are choosing to work and live on the street to escape extreme poverty and hunger in their familial households. Despite the multi-local spaces they inhabit, they have been able to create unique non-kin relations while often maintaining family based linkages. This study, undertaken in two centers for boys in Tegucigalpa and Comayagua, Honduras analyzes the contextual dynamics and decision-making processes of Honduran youth regarding work and living arrangements in urban spaces.
Native mitochondrial RNA-binding complexes in kinetoplastid RNA editing differ in guide RNA composition

Mitochondrial mRNAs in kinetoplastids require extensive U-insertion/deletion editing that progresses 3′-to-5′ in small blocks, each directed by a guide RNA (gRNA), and exhibits substrate and developmental stage-specificity by unsolved mechanisms. Here, we address compositionally related factors, collectively known as the mitochondrial RNA-binding complex 1 (MRB1) or gRNA-binding complex (GRBC), that contain gRNA, have a dynamic protein composition, and transiently associate with several mitochondrial factors including RNA editing core complexes (RECC) and ribosomes. MRB1 controls editing by still unknown mechanisms. We performed the first next-generation sequencing study of native subcomplexes of MRB1, immunoselected via either RNA helicase 2 (REH2), that binds RNA and associates with unwinding activity, or MRB3010, that affects an early editing step. The particles contain either REH2 or MRB3010 but share the core GAP1 and other proteins detected by RNA photo-crosslinking. Analyses of the first editing blocks indicate an enrichment of several initiating gRNAs in the MRB3010-purified complex. Our data also indicate fast evolution of mRNA 3′ ends and strain-specific alternative 3′ editing within 3′ UTR or C-terminal protein-coding sequence that could impact mitochondrial physiology. Moreover, we found robust specific copurification of edited and pre-edited mRNAs, suggesting that these particles may bind both mRNA and gRNA editing substrates. We propose that multiple subcomplexes of MRB1 with different RNA/protein composition serve as a scaffold for specific assembly of editing substrates and RECC, thereby forming the editing holoenzyme. The MRB3010-subcomplex may promote early editing through its preferential recruitment of initiating gRNAs.
Relation Modules of Infinite Groups

Let Fn denote the free group of rank n and d(G) the minimal number of generators of the finitely generated group G. Suppose that R ↪ Fm ↠ G and S ↪ Fm ↠ G are presentations of G and let \(\bar R\) and \(\bar S\) denote the associated relation modules of G. It is well known that \(\bar R \oplus (\mathbb{Z}G)^{d(G)} \cong \bar S \oplus (\mathbb{Z}G)^{d(G)}\) even though it is quite possible that Open image in new window . However, to the best of the author’s knowledge no examples have appeared in the literature with the property that Open image in new window . Our purpose here is to exhibit, for each integer k ≥ 1, a group G that has presentations as above such that Open image in new window . Our approach depends on the existence of nonfree stably free modules over certain commutative rings and, in particular, on the existence of certain Hurwitz-Radon systems of matrices with integer entries discovered by Geramita and Pullman. This approach was motivated by results of Adams concerning the number of orthonormal (continuous) vector fields on spheres.
Conducting policy-relevant developmental psychopathology research

Policy, defined broadly to include public policy as well as institutional or organizational policy, is useful for sustaining change in human development and its contexts and systems. The role for developmental psychopathology research in policy analysis and policy making is discussed. To assure that developmental psychopathology research is useful for policy (or practice) requires rigorous strategic thinking, commonly called "systems thinking". Systems thinking is described and its usefulness tested with a specific example of human development change - that of delinquency career crime prevention. Policy implications are then drawn from the example and generalized to broader human developmental change.
Thermal modeling of hybrid microelectronics

An outline is presented of a computer thermal analysis model that inputs information for existing computer-aided design (CAD) layout files. This model assumes conductive heat flow to determine the difference in temperature from the junction-to-case for multiple heat sources and uses this information to create a CAD-compatible drawing of the isotherms. The development and input/output of the model are discussed. The model is verified by using experimental data obtained from hybrids built-up with thermal test chips. >