cssi/SciSciGPT-SciSciNet huggingface dataset:
On the tangent modulus tensor in hyperelasticity

The tangent modulus tensor, denoted asD, plays a central role in nonlinear finite element simulation of elastomeric components such as seals. It is derived from the strain energy functionw for isotropic elastomers. Using Kronecker product notation, a compact expression forD has been derived in Nicholson [1] and Nicholson and Lin [2] for invariant-based strain energy functions such as the Mooney-Rivlin model. In the current investigation, a corresponding expression is derived for stretch ratio-based strain energy functions such as the Ogden model. Compressible, incompressible and near-incompressible elastomers are addressed. The derived expressions are considerably more elaborate than their counterparts for invariant based models. As illustration,D is evaluated and presented for the torsion of a natural rubber shaft described by a three term Ogden model, using coefficients reported by Treloar.
Asymmetric snap-buckling of a column restrained by a stiff wire

A relatively simple example of asymmetric snap-through buckling in a continuous structure is the nonlinear problem of a cantilevered column restrained at its tip by a stiff wire, which is inclined at an acute angle to the column centerline, and loaded at its tip by a force perpendicular to the centerline. A parameter called μ, which is the nondimensional ratio of the flexural rigidity of the column to the combined extensional stiffness of the wire and the column centerline, determines the essential features of the buckling. If μ is zero, or is small compared to unity, the bending of the column is small enough to justify the use of linear bending theory for the column. Hence, even though the constraint is nonlinear, the solution to this problem is obtained in closed form. The critical point for the structure is found to be an asymmetric branching point for μ=0, while for μ positive, the critical point is a snap-through type. The effect of μ is similar to that induced by initial imperfections in more complex structures. For very small μ, the critical load is markedly decreased from the value for μ=0. Moreover, the graph of the load vs. tip deflection has the appearance of having an acute discontinuity in slope at the critical point for μ very small, although it is actually found that the graph has a horizontal tangent there.
Pitch/Roll Static Stability of Tension Leg Platforms

Severe hurricanes in recent years have raised concerns about the safety and the robustness of the Tension Leg Platform (TLP) concept in the deep water Gulf of Mexico. This study investigates the static stability of different types of TLPs representing those deployed in the Gulf of Mexico, under three different scenarios. That is, a TLP with an intact tendon system, a partially damaged tendon system, and a completely damaged tendon system. The two types of TLP chosen for this study are the conventional four-leg TLP (C-TLP) and the Mono-column TLP. To avoid buckling and yielding occurring in a tendon, the maximum righting moment provided by an intact or partially damaged tendon system is reached when the tension in one or more tendons on the down tension leg becomes zero or when the tension in one or more tendons on the up tension leg reach the yielding strength. This definition leads us to identify the most sensitive directions of met-ocean conditions to a TLP with an intact or partially damaged tendon system. Hence, our finding may also be used in the study on the dynamic simulations of a TLP. The righting moments of each TLP in the three different scenarios are respectively computed and compared with related wind-induce static upsetting moment at certain velocities. By comparing their ratios, the static stability of a TLP and the redundancy of its tendon system may be revealed, which has important implication to its design.Copyright © 2010 by ASME
Nerve Growth Factor-induced Neuronal Differentiation Requires Generation of Rac1-regulated Reactive Oxygen Species

Nerve growth factor (NGF) stimulation of pheochromocytoma PC12 cells transiently increased the intracellular concentration of reactive oxygen species (ROS). This increase was blocked by the chemical antioxidant N-acetylcysteine and a flavoprotein inhibitor, diphenylene iodonium. NGF responses of PC12 cells, including neurite outgrowth, tyrosine phosphorylation, and AP-1 activation, was inhibited when ROS production was prevented byN-acetylcysteine and diphenylene iodonium. The expression of dominant negative Rac1N17 blocked induction of both ROS generation and morphological differentiation by NGF. The ROS produced appears to be H2O2, because the introduction of catalase into the cells abolished NGF-induced neurite outgrowth, ROS production, and tyrosine phosphorylation. These results suggest that the ROS, perhaps H2O2, acts as an intracellular signal mediator for NGF-induced neuronal differentiation and that NGF-stimulated ROS production is regulated by Rac1 and a flavoprotein-binding protein similar to the phagocytic NADPH oxidase.
A PRELIMINARY STUDY FOR EVALUATING THE CAPACITY OF WATERS FOR RECREATIONAL BOATING

The tremendous growth of participation in recreational boating has focused attention on the ability of surface waters to support different types of water-based recreation under intensive use. An important factor in determining the capacity of recreational waters for boating is the satisfaction boaters derive from an area and its use. The recreational experiences of two groups of users as they were affected by levels of use were examined on three intensively used lakes in southeastern Michigan during the summer of 1969. The reactions toward levels of use were obtained from personal interviews with users at the access sites following participation and by self-administered questionnaires distributed to shoreline property owner users. The level of use was recorded by aerial photography at hour intervals. The dispersion of boats and area consumed by boats on the water surface areas over time were quantified and investigated individually and in combination for possible relationships describing the level of use. The satisfaction of users was defined in terms of an index calculated by dividing the number of unfavorable boater responses by the total number of responses for a given time and place. Definite mathematical relationships between levels of use and user satisfaction were established. Based on these relationships, a range of levels of satisfaction for various numbers and groupings of boaters was used to develop boating carrying capacity limits.
Performance-Level Evaluation Methods Used in Management Development Studies from 1986 to 2000

A review of the evaluation literature shows that there has been a resurgence of interest in the evaluation of management development programs by human resource development (HRD) professionals. However, there remains a question of how well evaluation models measure the achievement of intended outcomes, especially where the program goal is the enhancement of organizational performance. This article analyzes management development interventions from 1986 to 2000 through a results assessment lens to determine common evaluation characteristics in organizational performance improvement efforts. The implication of factors such as timing of evaluation, evaluation methods, management development intervention categories, instrumentation, and measurement of organizational performance are discussed in this manuscript. Findings reveal that HRD professionals must take the leadership in the development of evaluation activities, especially those that test the long-term impact of the intervention on the organization.
Two-dimensional ultrasound image matching system for photodynamic therapy

Two-dimensional (2D) ultrasound imaging is commonly used for diagnosis in a variety of medical fields. However, there are several drawbacks of conventional 2D-ultrasound imaging. These include prostate or transducer movement that produces sets of different images that are difficult to interpret. Also during patient's reexamination correspondence between sets of images before reexamination and after is difficult to establish. This can be described as a problem of correlation between two sets of images: the first created before distortion or examination, the second one after. We propose a method to register 2D ultrasound volumes based on external markers introduced in the prostate. The metal balls are inserted in the prostate at three distinct locations in the prostate. These appear as bright dots in the ultrasound field, serve as reference points, are then outlined through a user-interactive program from two sets of images. Then, the computer program rotates and translates till they match respectively, and displays the mapped points with their corresponding location. Based on this idea we developed an image-guided system for PDT that require high-precision placement of implants. In the planning stage, the system performs an automatic acquisition of 2D transrectal ultrasound images that will ultimately be used to construct the treatment plan. At the time of the therapy, new sets of ultrasound images are acquired and a match is established between the virtual world and the patient's real world with the aid of manually introduced markers and image matching algorithms.
Leukoencephalopathy, Cerebral Calcifications, and Cysts in Two Sisters

Abstract Background The triad of leukoencephalopathy with cerebral calcifications and cysts is a rare syndrome consisting of these three radiographic findings first described by Labrune et al. in 1996. The inheritance pattern and genetic mutation responsible for this syndrome (if any) have not been determined. Patient description We report the occurrence of this syndrome in siblings. Two sisters presented with leukoencephalopathy, cerebral calcifications, and cysts approximately 10 years apart, one at 18 years with longstanding epilepsy and the other at 25 years with postpartum stroke-like signs. In both individuals, computed tomography revealed calcifications in the basal ganglia and subcortical white matter as well as supratentorial cysts. Magnetic resonance imaging demonstrated diffuse white matter increased T 2 signal and bilateral supratentorial cysts with enhancing walls. Both patients underwent biopsy, one an open biopsy and the other a stereotactic biopsy, with sections of the resected tissue revealing gliosis with Rosenthal fibers, myelin loss, and calcifications, plus in the larger sample cystic spaces and thick-walled abnormal blood vessels with hemosiderin deposition in the adjacent tissues. Conclusion In these siblings, the triad of radiological findings, histopathologic findings, and lack of extraneurological findings on physical examination suggest an occurrence of familial leukoencephalopathy, cerebral calcifications, and cysts with probable autosomal recessive inheritance.
Phenomenological potentials for QCD order parameters.

We discuss an effective potential for QCD from a phenomenological point of view. The potential is expressed in terms of order parameters of the gluon and chiral condensates and a scale is set by using the value of obtained from QCD sum-rule studies. We point out that in the case of nontopological soliton model of hadrons, the quantity which plays the role of the ''bag constant'' is not a renormalization-group invariant and therefore should not be identified with the energy density of the vacuum. Our model also provides a simple characterization of the mass matrix coupling scalar gluonium and scalar quarkonium. Further, the structure of the model is such that the dependence of the condensate order parameters on temperature and baryon density (as determined in lattice-gauge studies) may be readily parametrized. We also discuss the results of certain nuclear-physics experiments in terms of the dependence of QCD order parameters on baryon density.
Surface tension parameterization in molecular dynamics simulations of a phospholipid-bilayer membrane: Calibration and effects

Molecular dynamics simulations of interfacial systems such as phospholipid bilayers require experimental estimates of either the surface area per lipid or the surface tension (y). To investigate the mode of selection of yvalues, we have carried out the molecular dynamics (MD) simulations described here for a neat DMPC bilayer comprising 90 lipids using NP N γT and NP N AT ensembles. Influence of y values coupled with the effect of force truncation for both NP N γT and NP N AT ensembles was analyzed in multiple simulations. The membrane structural properties were studied comparatively using different y values in NP N γT ensembles with a spherical cutoff of 18 A and particle mesh Ewald method (PME) that takes long-range electrostatic interactions into account. In parallel, we tested the sensitivity of calculated y value in simulations using NP N AT ensembles with four different spherical cutoffs and PME. Our studies suggest that when PME is used to calculate the nonbonded forces, the value of surface tension for the system of this size should be in the range of 25 to 30 dyn/cm (per interface). On the other hand, for simulations with a cutoff of 18 A, shrinkage of box size of about 7-10% is observed for y values ranging from 0 to 85 dyn/cm. The surface tension value has to be raised to 625 dyn/cm to keep the surface area/lipid close to the experimental estimate for neat DMPC bilayers. Molecular dynamics simulations were also carried out with the opioid peptide dynorphin A(1-13) embedded within the DMPC bilayers. Several y values were tested with two electrostatic schemes. Our results demonstrated that for y values 0, 45, and 65 dyn/cm, due to the shrinkage of box size, the α-helical structure in the N-terminal region of the peptide is distorted with an 18 A cutoff. When the y value is increased to 625 dyn/cm with an 18 A cutoff or when PME is used with y = 25 dyn/cm, the peptide's α-helical structure is maintained and its orientation is similar to that obtained from earlier simulations 3 5 using NVE ensembles. The aromatic side chains in the peptide (Tyr-1 and Phe-4) interacted similarly in all the simulations except when γ=0 is used with a cutoff of 18 A. All constant surface tension simulations were compared with constant area ensembles in which the surface area/lipid remains fixed. Our results suggest that neglect of long-ranged electrostatic interactions and/or incorrect surface tension value results in serious artifacts in membrane simulations and suggest that caution is required when constant surface tension simulations are carried out on neat bilayers. In simulations of membranes with an embedded solute, the choice of an appropriate y value is more complex, as it will affect both the structure and the interactions of the solute within the bilayer.
Magnetic Force Microscopy of an Oxygen‐Sensing Spin‐Probe

In the present work we provide magnetic force microscopy (MFM) analysis on particles of a paramagnetic spin-probe lithium octa-n-butoxy-naphthalo-cyanine (LiNc-BuO) used for EPR oximetry. We demonstrate how MFM can generate a magnetic contrast in ambient air for LiNc-BuO particles when they assemble into structures >50 nm in size. The same sample when assembled into particles <10 nm in size failed to show contrast in MFM images. The potential for utilizing MFM to understand the magnetic signature of paramagnetic nanoparticles in biological samples is discussed.
An integrated MESFET voltage follower LDO for high power and PSR RF and analog applications

A CMOS low dropout linear regulator (LDO) with a MESFET based follower output stage was designed and fabricated on a commercial 45nm SOI CMOS technology. The proposed LDO demonstrates a dropout voltage of <170mV at 1A load current while occupying 0.245mm2 of die area. The approach includes a novel depletion mode n-channel MESFET in a low output impedance source follower configuration. This enables the LDO to achieve stable operation under all line and load conditions without the need for generating higher internal voltage rails or external compensation. The compact structure and its inherent stability make it ideal for high powered analog, mixed signal and RF system-on-chip applications that require high PSR under different loading conditions.
Heat transfer to liquid metals along a circular cylinder with uniform surface heat flux

Abstract The effects of axial heat conduction on laminar forced convective heat transfer to liquid metals along a circular cylinder are studied analytically for the case of uniform surface heat flux. The transformed conservation equations governing the nonsimilar boundary layers are solved by the local nonsimilarity method. Local heat transfer results are presented for liquid metals having Prandtl numbers of 0.003, 0.008, and 0.03 over a wide range of values of the transverse curvature and axial heat conduction parameter. It is found that the local Nusselt number increases with increasing transverse curvature of the cylindrical surface, with increasing axial heat conduction effect (i.e., decreasing Peclet number), and with increasing Prandtl number.
Targeted and proximity-dependent promiscuous protein biotinylation by a mutant Escherichia coli biotin protein ligase

A method for general protein biotinylation by enzymatic means has been developed. A mutant form (R118G) of the biotin protein ligase (BirA) of Escherichia coli is used and biotinylation is thought to proceed by chemical acylation of protein lysine side chains by biotinoyl-5'-AMP released from the mutant protein. Bovine serum albumin, chloramphenicol acetyltransferase, immunoglobulin chains and RNAse A as well as a large number of E. coli proteins have been biotinylated. The biotinylation reaction is proximity dependent in that the extent of biotinylation is much greater when the ligase is coupled to the acceptor protein than when the acceptor is free in solution. This is presumably due to rapid hydrolysis of the acylation agent, biotinoyl-5'-AMP. Therefore, when the mutant ligase is attached to one partner involved in a protein-protein interaction, it can be used to specifically tag the other partner with biotin, thereby permitting facile detection and recovery of the proteins by existing avidin/streptavidin technology.
Peripheral endothelin B receptor agonist-induced antinociception involves endogenous opioids in mice.

Abstract Endothelin-1 (ET-1) produced by various cancers is known to be responsible for inducing pain. While ET-1 binding to ETAR on peripheral nerves clearly mediates nociception, effects from binding to ETBR are less clear. The present study assessed the effects of ETBR activation and the role of endogenous opioid analgesia in carcinoma pain using an orthotopic cancer pain mouse model. mRNA expression analysis showed that ET-1 was nearly doubled while ETBR was significantly down-regulated in a human oral SCC cell line compared to normal oral keratinocytes (NOK). Squamous cell carcinoma (SCC) cell culture treated with an ETBR agonist (10 −4 M, 10 −5 M, and 10 −6 M BQ-3020) significantly increased the production of β-endorphin without any effects on leu-enkephalin or dynorphin. Cancer inoculated in the hind paw of athymic mice with SCC induced significant pain, as indicated by reduction of paw withdrawal thresholds in response to mechanical stimulation, compared to sham-injected and NOK-injected groups. Intratumor administration of 3 mg/kg BQ-3020 attenuated cancer pain by approximately 50% up to 3 h post-injection compared to PBS-vehicle and contralateral injection, while intratumor ETBR antagonist BQ-788 treatment (100 and 300 μg/kg and 3 mg/kg) had no effects. Local naloxone methiodide (500 μg/kg) or selective μ-opioid receptor antagonist (CTOP, 500 μg/kg) injection reversed ETBR agonist-induced antinociception in cancer animals. We propose that these results demonstrate that peripheral ETBR agonism attenuates carcinoma pain by modulating β-endorphins released from the SCC to act on peripheral opioid receptors found in the cancer microenvironment.
Flow visualization study of grooved surface/surfactant/air sheet interaction

The effects of groove geometry, surfactants, and airflow rate have been ascertained by a flow-visualization study of grooved-surface models which addresses the possible conditions for skin friction-reduction in marine vehicles. It is found that the grooved surface geometry holds the injected bubble stream near the wall and, in some cases, results in a 'tube' of air which remains attached to the wall. It is noted that groove dimension and the use of surfactants can substantially affect the stability of this air tube; deeper grooves, surfactants with high contact angles, and angled air injection, are all found to increase the stability of the attached air tube, while convected disturbances and high shear increase interfacial instability.
Pump-Probe Experimental Study of Phonon Reflectivity at an Interface and Phonon Relaxation Time

Heat transfer in nanostructures differs significantly from that in macrostructures because of classical and quantum size effects on energy carriers, i.e., phonons, electrons, and photons [1–3]. Understanding thermal transport in nanostructures is of fundamental importance to a variety of technologies, including thermal management of nanoelectronics and optoelectronics, energy conversion, nanofabrication, and sensor development. A better understanding of the energy transport at nanoscale calls for both simulations and experimental techniques on thermal transport in nanostructures.Copyright © 2005 by ASME
Thermokinetic Modeling of Phase Transformation in the Laser Powder Deposition Process

A finite element model coupled with a thermokinetic model is developed to predict the phase transformation of the laser deposition of AISI 4140 on a substrate with the same material. Four different deposition patterns, long-bead, short-bead, spiral-in, and spiral-out, are used to cover a similar area. Using a finite element model, the temperature history of the laser powder deposition (LPD) process is determined. The martensite transformation as well as martensite tempering is considered to calculate the final fraction of martensite, ferrite, cementite, e-carbide, and retained austenite. Comparing the surface hardness topography of different patterns reveals that path planning is a critical parameter in laser surface modification. The predicted results are in a close agreement with the experimental results.
Abstract 1689: The cytoprotective role of the UPR during c-Myc dependent transformation and tumor progression.

The Unfolded Protein Response (UPR) is a conserved cellular adaptation program that is elicited due to the accumulation of unfolded proteins in the endoplasmic reticulum (ER). The PERK-pEIF2A-ATF4 arm of UPR is triggered by ER stress and primarily serves in the global attenuation of protein translation, and promotes cell survival via selective upregulation of stress induced genes. We recently showed that oncogenic Myc activation initiates UPR due to the accumulation of unfolded proteins in the ER. Using multiple genetic models, we demonstrated that ablation of UPR signaling leads to decreased cell survival in vitro and reduced tumor growth in vivo. The proto-oncogene c-Myc has been shown to activate both pro-tumorigenic and anti-tumorigenic pathways. In c-Myc driven cancers, the pro-apoptotic state is bypassed via a yet undefined pro-survival mechanism. We are interested in elucidating the role of UPR in promoting activation of pro-survival pathways during c-Myc induced tumorigenesis. We previously demonstrated that autophagy, one such pro-survival pathway, is induced and sustained during c-Myc activation in a PERK dependent manner. Moreover, genetic and pharmacological inhibition of autophagy in c-Myc induced cells decreases cell survival. Using a Qiagen Autophagy PCR Array system we screened for autophagy genes that were differentially expressed in a c-Myc dependent manner. Preliminary results indicate that several genes that regulate different steps of autophagy such as ATG9b, ATG5 and ATG16L1 are upregulated upon c-Myc induction, which was validated by qPCR. In PERK-/- MEFs, ATG5 and ATG16L1 were not upregulated and LC3B processing, a marker of autophagy induction, was significantly attenuated upon c-Myc activation. This indicates that PERK is required for the induction of autophagy genes upon c-Myc activation. To further investigate the role of the PERK-pEIF2A-ATF4 arm of UPR in cell survival during c-Myc induction, we looked at the transcription factor ATF4 which is a major downstream mediator of PERK. Using ATF4-/- MEFs, we observed significant cell death and decreased clonogenic survival upon c-Myc activation compared to ATF4+/+ MEFs. We are currently investigating how ATF4 is mediating cell survival during c-Myc induction. Our findings establish that UPR plays as an activator of pro-survival pathways such as autophagy and therefore UPR can be targeted as a therapy modality in c-Myc driven cancers. This research is supported by NIH grant 5R01CA139362-04 Citation Format: Feven Tameire, Lori S. Hart, Bo Qiu, Constantinos Koumenis. The cytoprotective role of the UPR during c-Myc dependent transformation and tumor progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1689. doi:10.1158/1538-7445.AM2013-1689
The cost-effectiveness of fluorodeoxyglucose 18-F positron emission tomography in the N0 neck.

BACKGROUND Although surgery and radiation are effective treatments of regional lymphatics for classification N0 head and neck squamous cell carcinoma (HNSCC) patients, both have morbidities that could be avoided in approximately 70% of patients without lymph node disease with better diagnostic information. 18-F fluoro-2-deoxyglucose positron emission tomography (FDG-PET) has shown promise in detecting subclinical lymph node disease, but its cost and availability have limited its use. Here, we sought to determine whether the use of FDG-PET was cost-effective as part of a treatment strategy for classification N0 HNSCC patients. METHODS The cost-effectiveness of proceeding from classification of N0 by computed tomography to a PET scan was estimated using standard methods of economic evaluation. Costs were for a large, Midwestern university medical center. Probabilities were computed from a review of the literature. Utilities were obtained by a time-tradeoff method, and life expectancy was estimated using the Surveillance, Epidemiology, and End Results database. Outcomes measures were cost per year of life saved and cost per quality-adjusted life-year. RESULTS Modified radical neck dissection was associated with the lowest morbidity (utility [u] = 0.93), and radical neck dissection plus radiation was associated with the highest (u = 0.68). Life expectancy was estimated to be 5.9 and 11.5 years for patients with and without lymph node disease, respectively. The incremental cost-effectiveness ratio for the PET strategy was $8718 per year of life saved, or $2505 per quality-adjusted life-year. CONCLUSIONS A diagnostic and treatment strategy that proceeds from classification of N0 to a PET scan is cost-effective. Prospective studies that evaluate this strategy are important to assure that these simulation results are realized in clinical practice. Cancer 2001;92:2341–8. © 2001 American Cancer Society.
Influence of added manganese on nitrification in a low-manganese soil

Nitrification was studied in a Leefield sand, sufficiently low in Mn to produce severe Mn deficiency in soybeans. The soil was treated with 100 μg/g NH4+-N, 0, 10, 100 and 1000 μg/g Mn, and incubated at field capacity for six weeks at 30°C. Weekly determinations of (NO3-+NO2-)-N and NH4+-N revealed that nitrification was not increased above the control level by any of the Mn rates. In the control, the decrease in soil pH associated with nitrification caused an increase in extractable Mn from 0.12 to 1.56 μg/g during the experimental period. The 1000 μg/g rate of Mn completely inhibited nitrification for the first five weeks of the experiment, but nitrification began to occur during the sixth (last) week. It is postulated that Mn was being converted to unavailable forms such that by the sixth week the level of active Mn had been reduced sufficiently to permit nitrification to begin. re]19760512
New synthetic medium for the culture of premature barley embryos.

The preparative procedure is presented for a new, synthetic plant tissue culture medium designed specifically for the culture of excised barley embryos. The medium appears capable of supporting development of premature barley embryos with high survivability.
Loan rates as a selective credit control

When the monetary authorities set interest rates above or below market-clearing levels, loan markets are in disequilibrium. The success of a policy that is aimed at favoring some sectors of the economy with relatively low loan rates depends on the state of the various loan markets. That policy will be most definitely effective when loans to the favored sectors are in excess demand while other types of loans are in excess supply. It may be less successful when all loans are in excess supply and counterproductive when they are in excess demand.
Wisconsin counties as political chessmen

Partisan elections of county officials, with its consequent local political machinery, proves an aid in the election of state officials by the dominant party group.
Gold/fluorocarbon adhesion

The adhesion of laminated glass fiber reinforced Teflon® PFA to gold was studied. The results of adhesion testing performed by 90° peeling showed a strong dependency of gold/PFA adhesion on the lamination temperature. The possibility of chemical reaction at the gold/PFA interface is discussed.
Fluorescence-Detected Stopped Flow with a Pyrene Labeled Substrate Reveals That Guanosine Facilitates Docking of the 5' Cleavage Site into a High Free Energy Binding Mode in the Tetrahymena Ribozyme

Fluorescence-detected stopped flow kinetics are reported for binding of pyrene (pyr) labeled oligonucleotide substrates, pyrCUCUA and pyrCCUCUA, to the L-21 ScaI ribozyme from Tetrahymena thermophila. Both oligomer substrates contain a UA sequence that mimics the cleavage site where pG attacks the self-splicing group I intron from which the ribozyme was derived. Kinetics were measured in the presence and absence of saturating 5'-monophosphate guanosine substrate (pG) at 5 mM Mg2+ and 15 degrees C. In the absence of pG, binding of both oligonucleotide substrates is consistent with a one step mechanism involving only base pairing. Upon addition of pG, pyrCCUCUA is observed to bind in two steps: base pairing to the ribozyme to form the P1 helix and, presumably, subsequent docking of the P1 helix into the catalytic core. A third transient is also observed, which likely includes the chemical step following docking. All rate constants are measured for this mechanism. Surprisingly, the equilibrium constant for docking, K2, is unfavorable in the absence of pG (K2 < 1) and only modestly favorable in the presence of pG (K2 = 4). These results contrast with those for a 5' exon mimic, pyrCCUCU, in which docking is strongly favored under the above conditions in the absence of pG; K2 = 100 [Bevilacqua, P. C., Kierzek, R., Johnson, K. A., & Turner, D. H. (1992) Science 258, 1355-1358]. These results suggest an unfavorable interaction between the ribozyme and the pA at the site of cleavage. Implications are discussed for the catalytic strategy of the ribozyme and for the self-splicing cascade that occurs in nature.
Correctional employees' reactions to job characteristics: A data based argument for job enlargement

Abstract Job enlargement, an industrial organization innovation that allows workers (within limits) greater responsibility for their jobs is explored and discussed in relation to correctional personnel. Based on responses to tests administered to 104 correctional personnel in a Midwestern state, it was found that industrial findings generalize to corrections. Job enlargement is recommended to improved the personnel and managerial aspects of the correctional institution, to bring the institution into conformity with environmental reality, and to overcome the therapy-custody dichotomy.
The laparoscopic experience of surgical graduates in the United States.

Background: Although laparoscopic surgery has become widespread during the past decade, no systematic study of the training needs exists. To obtain guidance for planning, we analyzed the national resident operative experience during the past 8 years. Methods: The laparoscopic experiences of all surgical residents graduating between 1994 and 2001 were subjected to regression analysis. The laparoscopic volume of each trainee and change in ratio of laparoscopic/open operation over time were used to estimate the growth of individual laparoscopic operations in training programs. Results: Laparoscopic surgery constituted only 5.7% of a trainee’s total surgical experience in 1994, but comprised 13% by 2001. A resident completing training in 1994 performed 53 laparoscopic operations, of which 79% (42) were cholecystectomies. By 2001, a graduate performed 126 laparoscopic operations, of which 68% (86) were cholecystectomies. During the interim, most laparoscopic operations exhibited growth. Trainee experience in some newer operations has also increased steadily but at a much slower rate. Conclusions: This descriptive statistical survey of training experience yields a comprehensive picture of the laparoscopic capability of the young surgeon. The growth potential of some newer operations has also been measured. Using these data, guidelines can be drawn as to which operation programs should focus resources on training residents. Since competence depends on exposure, residency training alone may not provide sufficient depth to allow recent graduates to perform the newer operations independently.
The oncogenic potential of three different 7,12-dimethylbenz- (a)anthracene transformed c3h/10t1/2 cell clones at various passages and the importance of the mode of immunosuppression.

Abstract The oncogenic potential of C3H/10T 1 2 cells which were transformed in vitro with 7,12-dimethylbenz(a) anthracene is reported. The ability of the cells to grow as malignant tumors insyngeneic immunosuppressed mice was used as parameter for oncogenic potential. Cells of types I, II and III were assayed at several dosage levels, i.e., 10 4 , 10 5 or 10 6 cells per inoculum, with or without immunosuppression by antithymocyte serum globulin fraction. The studies were performed in several strains of host animals, i.e., male and female syngeneic C3H mice supplied by the National Cancer Institute, C 3 H mice supplied by Charles River and nude, athymic female mice. Morphological transformation preceded oncogenic transformation, and type I cells could not be established as tumors. Type II and type III cells developed oncogenic potential only after several passages in culture. Oncogenic potential was pronounced in the type III cells, and less strongly expressed in type II cells. Also tested were different methods of immunosuppression of the animal against the expression of the oncogenic potential of DMBA transformed C3H/10T 1 2 cells from type II and III clones. Immunosuppression by antithymocyte serum globulin fraction was an effective method of preparing the syngeneic host so that cells with a low oncogenic potential would grow as tumors, whereas total body irradiation was not effective. For cells with a high oncogenic potential both ways of immunosuppression were sufficient. Admixing lethally irradiated cells in the cell inoculum slightly enhanced the tumor development from cells with low oncogenic potential and such addition was clearly effective for cells with a higher oncogenic potential, both for the antibody-treated and for the irradiated series. The findings were reproducible. The study stresses the importance of immunosuppression by antithymocyte globulins for detecting in vitro transformed weakly oncogenic cells.
Isolation and characterization of irradiation fusion hybrids from mouse Chromosome 1 for mapping Rmc-1, a gene encoding a cellular receptor for MCF class murine retroviruses

An irradiation-reduced somatic cell hybrid mapping panel was constructed of BALB/c mouse Chromosome 1. Nineteen hybrids were selected from a pool of 292 clones to generate a fine structure physical map of the distal 40 cM of the chromosome. The hybrids contain mouse DNA fragments only from Chromosome 1, ranging from approximately 5 cM to approximately 20 cM. Utilizing a viral infectibility assay, a cellular receptor gene, Rmc-1, for the MCF class of murine retroviruses was found to be linked to Lamb2, in the region between the Lamb2 and Bxv-1 loci. In addition, analysis of the hybrid mapping panel resulted in the remapping of three loci, Atpb, Ly-5, and Pmv-24, as compared to the mouse linkage map. Two previously unmapped endogenous proviruses are also putatively assigned positions on the chromosome.
On the t-cumulative probabilities

In this paper we give an alternative to show the relationship between t and Beta using generalized logistic distribution. An expression for t-cumulative probabilities is then derived by evaluating the incomplete beta integral. An algorithm is also given for computing the t probabilities. This algorithm seems to have some desirable numerical properties.
Loose Identity and Becoming Something Else

We are practiced at attributing numerical identity to things that, when we consider them another way, seem obviously distinct. These practices are well established and raise no question except among metaphysicians engaged in their requisite initial obtuseness. So, for example, we say the same tornado that went by here leveled Pittsfield later. We say this despite the fact that, plausibly, at neither time is there really even a single individual thing, much less the same individual thing. Identity is attributed to successively different pluralities of air, moisture, dust, and debris, as if they were a single continued thing and rightly so. Metaphysicians rightly insist, however, that distinct things can't be identical, on pain of contradiction. Since cases like the above seem to present this contradiction, an explanation is needed why they really don't. An historically important move is to say that such cases are cases of identity in name only. Identity doesn't really hold between the distinct things attributed identity. Whatever relevant relation does hold between them is called "imperfect identity" or "identity in the loose and popular sense" to capture both that the word 'identity' is used and yet it is to some extent abused.' Let's assume that this move is the best one. I won't argue that it is; I think there is a better. But considering how an account of loose identity should go is a step in the direction of my preferred account.2 Assuming a loose identity account requires supposing that the tornado is at best successive distinct single things (and at worst not a single thing at any time at all). Why grant this supposition? Why not say that in addition to the successive single things, there is a whole that they compose? They are its temporal parts. The whole is the tornado. Its identity through time is straightforward. Even at a time, besides the various bits, there is the whole that they compose. The tornado's singleness at a time is also straightforward. Why not say these things, and dispense with an account of loose identity?
Identifying Context Variables in Research on Writing A Review and Suggested Directions

This article identifies context variables in written composition from theoretical perspectives in cognitive psychology, sociology, and anthropology. It also shows how multiple views of context from...
Remodeling of Marrow Hematopoietic Stem and Progenitor Cells by Non-self ST6Gal-1 Sialyltransferase

Glycans occupy the critical cell surface interface between hematopoietic cells and their marrow niches. Typically, glycosyltransferases reside within the intracellular secretory apparatus, and each cell autonomously generates its own cell surface glycans. In this study, we report an alternate pathway to generate cell surface glycans where remotely produced glycosyltransferases remodel surfaces of target cells and for which endogenous expression of the cognate enzymes is not required. Our data show that extracellular ST6Gal-1 sialyltransferase, originating mostly from the liver and released into circulation, targets marrow hematopoietic stem and progenitor cells (HSPCs) and mediates the formation of cell surface α2,6-linked sialic acids on HSPCs as assessed by binding to the specific lectins Sambucus nigra agglutinin and Polysporus squamosus lectin and confirmed by mass spectrometry. Marrow HSPCs, operationally defined as the Lin−c-Kit+ and Lin−Sca-1+c-Kit+ populations, express negligible endogenous ST6Gal-1. Animals with reduced circulatory ST6Gal-1 have marrow Lin−Sca-1+c-Kit+ cells with reduced S. nigra agglutinin reactivity. Bone marrow chimeras demonstrated that α2,6-sialylation of HSPCs is profoundly dependent on circulatory ST6Gal-1 status of the recipients and independent of the ability of HSPCs to express endogenous ST6Gal-1. Biologically, HSPC abundance in the marrow is inversely related to circulatory ST6Gal-1 status, and this relationship is recapitulated in the bone marrow chimeras. We propose that remotely produced, rather than the endogenously expressed, ST6Gal-1 is the principal modifier of HSPC glycans for α2,6-sialic acids. In so doing, liver-produced ST6Gal-1 may be a potent systemic regulator of hematopoiesis.
Singularities in first-order phase transitions

Abstract Several theories of phase transitions and their inter-relations have been criticized, focusing on the problem of whether z c, the value of the fugacity corresponding to the point of condensation, is given by z s, the smallest real positive singularity of the analytic function defined by the power series using volume-independent cluster integrals, or not. The present situation has been analysed and it is made clear that none of the existing theories can give the answer to this problem. Plausibility arguments for an affirmative or negative answer are discussed.
Counter-current recycle membrane cascades for the separation of the boron isotopes in BF3

Abstract Recent research has shown that the stable isotopes of boron ( 10 B, 11 B) can be separated by permeation of BF 3 gas through modified polymeric and immobilized liquid membranes. Observed separation factors ranged from about α*=1.02-1.09. The present paper investigates membrane cascade requirements to separate the boron isotopes if suitable membranes could be fabricated which exhibit separation factors in the mid-range of those observed, i.e. at α* = 1.04-1.07. The calculations show that 95 percent 10 B could be produced using simple, ideal counter-current recycle cascades containing from ca. 100 to 290 stages, depending on α* and overall cut. Constant recycle ratio and “squared-off” cascades require fewer stages but have larger area and compressor duty requirements. A properly designed “squared-off” cascade approaches the performance of an ideal cascade and may be a practical alternative to the ideal cascade which would require a different area and compressor size for each stage.
Arrhenius Model Thermal Damage Coefficients for Birefringence Loss in Rabbit Myocardium

Estimating effective thermal damage process coefficients for the first order kinetic model of damage processes is not difficult when the temperature is held constant for a substantial period. Laser coagulation experiments, however, are of short duration and, because of non uniform beam profiles, exhibit important heat transfer effects: the thermal histories are transient by nature and spatial temperature gradients are significant. Estimates of activation energy, E, and collision frequency factor, A, were obtained from transient laser exposure of freshly-excised rabbit myocardium. The transient exposures were converted to equivalent constant temperature exposures using A-E plane plots. The equivalent constant temperature conditions were then plotted on standard Arrhenius axes to estimate the activation energy, E (kj/mole) and frequency factor, A (1/s).Copyright © 2003 by ASME
Pollen cones from the late triassic of North America and implications on conifer evolution

Abstract Pollen grains extracted from a new late Triassic pollen cone are examined at the ultrastructural level. The grains are protosaccate with the sacci slightly inclined toward the germinal furrow on the distal face of the corpus. The affinities of this Triassic cone are suggested together with a discussion on the evolution of saccate pollen types.
Tunable laser photodissociation: quantum yield of I★(2P12) from Ch2I2

Abstract Tunable laser I★(2P 1 2 ) quantum-yield measurements are presented for CH2I2 in the wavelength range 248–340 nm. The results suggest that a curve-crossing mechanism is operative in the dissociation.
Differential modulation of behavioral effects of cocaine by low- and high-efficacy D1 agonists

Dopamine D1 agonists differing in efficacy with respect to stimulation of adenylate cyclase activity and other in vitro and in vivo criteria were evaluated for their capacity to modulate the behavioral effects of cocaine in squirrel monkeys. Monkeys were trained either to respond on a fixed-ratio schedule in which lever pressing terminated a stimulus associated with electric shock or to discriminate cocaine from vehicle using a two-lever drug-discrimination procedure. When administered in combination with cocaine, D1 agonists displaying relatively low efficacy (SKF 38393, SKF 75670) attenuated both the rate-altering effects of cocaine on fixed-ratio responding and the discriminative-stimulus effects of cocaine, resulting in overall rightward shifts of the cocaine dose-response functions. Maximal attenuation of the behavioral effects of cocaine by the D1 partial agonists was comparable to that produced by the D1 antagonist SCH 39166. In contrast, D1 agonists displaying relatively high efficacy (SKF 81297, SKF 82958, SKF 83189) either had little effect on or accentuated the rate-altering and discriminative-stimulus effects of cocaine. The results show that D1 partial agonists can act as functional cocaine antagonists and may be viable candidate medications for the management of cocaine addiction.
Measurement of energies using a glass-scintillator ionization spectrometer☆

A method is proposed for obtaining the energies of high-energy hadrons incident upon a glass-scintillator ionization spectrometer. The description of the apparatus and of its calibration with cosmic ray muons is followed by a demonstration of the processing of the data obtained.
Mission seeks to explore Pluto-Charon

The New Horizons project of the National Aeronautics and Space Administration sponsored a Pluto-Charon workshop last spring to review the latest advances in the science of the Pluto-Kuiper Belt (PKB), to hear predictions about the Pluto-Charon encounter, and to discuss new ideas for supporting ground-based and Earth-orbital observations. Currently awaiting approval to proceed to hardware implementation, the New Horizons mission will launch in January 2006, do a Jupiter swing-by in March 2007, and visit Pluto in the fall of 2015. It will then visit up to three Kuiper Belt Objects (KBOs). (More information on the New Horizons mission, Pluto, and the Kuiper Belt can be found in a recent Eos article, 5 March 2002, pp. 101,108-109).