cssi/SciSciGPT-SciSciNet huggingface dataset:
EXPLANATORINESS: CAUSE VERSUS CRAIG

In "Toward a Theory of the Process of Explanation", Ilpo Halonen and Jaakko Hintikka (2003) present two interlocking theses, one positive, one negative. Their positive thesis is that philosophical inquiries into the nature of explanation should begin with a theory that explicates the logical form of the process of explaining, [ms. 4] Given that explanations are the product of such processes, a theory of explanation will emerge as a con sequence of the theory of explaining. Their negative thesis is that the nature and importance of what they call the "covering law model" of explanations has been dramatically misunderstood. By analyzing the logical form of the process of explanation, Halonen and Hintikka endeavor to show that covering laws should be viewed not as premises, but rather as 'summaries' of explanatory arguments. The core of Halonen and Hintikka's positive thesis is a theory of the process of explaining which the authors dub the "interrogative nomological" model. Since the interrogative-nomological model is essen tially a special case of Hintikka's interrogative model of inquiry, [ms. 4] the explanatory process overall is viewed as an interrogative "argument", aimed at finding an answer to the question why E?, where E is the ex planandum. Such argument begins with a (possibly informal) background theory T, then proceeds with the explainer posing "questions" to nature (experiments) and nature yielding "answers" (results of experiments). At least a part of this process is aimed at establishing some suitable initial conditions / such that the explanandum can be logically derived from T and /. Accordingly, while explaining does contain a deductive element, it is not a purely deductive enterprise, [ms. 44] Halonen and Hintikka emphasize that the explanandum (and, presum ably, the explanans) can have any logical form whatsoever, [ms. 27] What is critical in explanations is the behavior of non-logical constants, [ms. 27] The constants in the explanandum fall into two mutually exclusive, but not necessarily exhaustive, classes: the critical and the queried constants. The critical ones are, so to speak, the values of the parameters that specify
A Cyber-physical Systems Approach to the Design of Vehicle Safety Networks

The concept of cooperative vehicle safety (CVS) is based on cooperation of vehicles in achieving real-time situation awareness for the purpose of safer (and possibly autonomous) driving. Since CVS is a safety system, situation awareness has to be real-time with high accuracy. Cooperation in the context of CVS is achieved through vehicular networks that are tuned to the purpose of vehicle state tracking in a neighborhood around each vehicle. In this paper, we describe different methodologies in approaching the design of CVS, and propose a systematic Cyber-Physical Systems approach to the design of CVS. Our proposed approach is to design the system in a top-down manner, by identifying system metrics such as approximate measures of awareness, and then characterizing component models and their interactions. For this purpose, processes that handle vehicle state estimation and dissemination of state information are studied and their interactions are modeled in order to derive an overall awareness quality metric. The result of analyzing and modeling such effects is then used in studying the design of adaptive control schemes for each component of CVS.
ZnS-ZnMgS-ZnS Lattice-Matched Gate Insulator as an Alternative for Silicon Dioxide on Silicon in Quantum Dot Gate FETs (QDGFETs)

This paper presents characteristics of two fabricated Si quantum dot gate field-effect transistors, one with SiOx-cladded Si dots on silicon dioxide as the gate insulator, and another with the same quantum dots on lattice-matched high-κ ZnS-ZnMgS-ZnS as the gate insulator. Simulations show that the oxide thickness should be within 80 A to generate a third state in the transfer characteristic of the quantum dot gate field-effect transistor. In the practical device, the silicon dioxide thickness varies between 20 A and 40 A. In this work we use high-κ dielectric thickness around 75 A to 80 A, which is equivalent to 32 A to 35 A of silicon dioxide.
Electron-impact excitation and ionization cross sections for the Si, Cl, and Ar isonuclear sequences

Electron-impact excitation and ionization cross sections are presented for all atomic ions in the Si, Cl, and Ar isonuclear sequences. These data contribute to the continuing effort to provide accurate collisional data for magnetic fusion and astrophysical modeling. For excitation processes, level-resolved cross section calculations are presented which were made using first-order many-body perturbation theory. For ionization processes, we present calculations made with the configuration-average approximation using a distorted-wave method. A selection of excitation and ionization cross sections are compared with experiment, where available. For ionization of ${\text{Si}}^{2+}$ and ${\text{Si}}^{3+}$, we also compare with calculations made using time-dependent close-coupling theory, to assess the accuracy of the distorted-wave calculations. Our cross sections will be tabulated in several atomic collision databases for use in future kinetics modeling efforts.
Ohio State University Libraries' net.TUTOR project

Abstract The Showcase of Ideas at the 1997 ACRL President's Program provided a valuable opportunity to share plans and a sample lesson from the Ohio State University Libraries' net.TUTOR program. At that time, net.TUTOR was in its initial development phase. This article, written from the perspective of almost 2 full years of managing and expanding this program, will discuss the early vision for net.TUTOR, how the program actually developed, how it has been used during the 2 years that followed, and future plans for the program.
The Effect of Preoperative Flurbiprofen on Miosis Produced by Acetylcholine During Cataract Surgery

Sustained pupillary dilation during cataract surgery may be achieved with preoperative noncorticosteroidal anti-inflammatory agents such as flurbiprofen. However, these agents may interfere with miosis after injection of acetylcholine. Thirty patients for extracapsular cataract extraction were randomly assigned in a double-masked fashion to receive either a placebo or preoperative 0.03% flurbiprofen every 30 minutes for four doses. All patients also received three doses of 2.5% phenylephrine and 2% cyclopentolate. Pupillary diameter was measured the day before surgery, immediately before the surgical incision, immediately before and five minutes after acetylcholine injection, and the morning after surgery. The flurbiprofen group had a larger mean pupillary diameter before injection of acetylcholine (P
Angular Dependence of the Acousto-Optical Effect

Abstract Equations are derived giving the transmission as a function of incident angle for ultrasonic waves passing through a liquid crystal cell. These equations are tested experimentally and compared with the light transmission which occurs via the “acousto-optic effect.” Maximum light transmission is found to occur for angles of maximum ultrasonic transmission. It would appear the equations can be used to prescribe cell design for maximizing the effect for a given ultrasonic frequency.
Influence of the small substitution of Z=Ni, Cu, Cr, V for Fe on the magnetic, magnetocaloric, and magnetoelastic properties of LaFe11.4Si1.6

Abstract We have studied the magnetic, magnetocaloric, and magnetostriction properties of LaFe 11.4 Si 1.6 and La(Fe 0.99 Z 0.01 ) 11.4 Si 1.6 (Z=Ni, Cu, Cr, V) compounds using magnetization and strain gauge techniques. It was found that substitution of 1% of the Fe by Z-elements results in an increase in the Curie temperature ( T C ), and affects the magnetostriction and magnetocaloric properties of the parent compound, LaFe 11.4 Si 1.6 . A maximum shift in T C of about 11 K, and significantly smaller hysteresis losses in the vicinity of T C compared with those of the base compound, were found for Z=V. The maximum magnetovolume coupling constant was estimated to be n dd ≈2.7×10 −3 ( μ B /Fe atom) −2 for the parent compound. The changes in the volume magnetostriction, the magnetovolume coupling constant, and the magnetocaloric properties are strongly correlated with composition. The relative effects of the variation in cell parameters and electron concentration on the magnetostriction, T C , and the magnetocaloric properties are discussed.
Signal Sequences for Targeting of Gene Therapy Products to Subcellular Compartments: The Role Of CRM1 in Nucleocytoplasmic Shuttling of the Protein Switch

Purpose The purpose of this study was to understand the mechanism of nuclear export of the protein switch, used for controlled intracellular delivery of gene products, by studying the involvement of classical export receptor CRM1.
Progress in equal-channel angular processing

Equal-channel angular processing (ECAP) is an efficient method of refining grain size via severe plastic deformation. The ECAP technique retains the size and shape of the billet, induces large cumulative strains in the material, and develops different microstructures. A description of plastic deformation during ECAP in the rigid plastic approach is provided. A survey of experimental and finite-element modeling (FEM) results is presented with regard to the plastic deformation zone (PDZ) formation, which includes the effect of materials properties on the metal flow through the ECAP die.
Applications of laser direct-write for embedding microelectronics

The use of direct-write techniques might revolutionize the way microelectronic devices such as interconnects, passives, IC's, antennas, sensors and power sources are designed and fabricated. The Naval Research Laboratory has developed a laser-based microfabrication process for direct-writing the materials and components required for the assembly and interconnection of the above devices. This laser direct-write (LDW) technique is capable of operating in subtractive, additive, and transfer mode. In subtractive mode, the system operates as a laser micromachining workstation capable of achieving precise depth and surface roughness control. In additive mode, the system utilizes a laser-forward transfer process for the deposition of metals, oxides, polymers and composites under ambient conditions onto virtually any type of surface, thus functioning as a laser printer for patterns of electronic materials. Furthermore, in transfer mode, the system is capable of transferring individual devices, such as semiconductor bare die or surface mount devices, inside a trench or recess in a substrate, thus performing the same function of the pick-and-place machines used in circuit board manufacture. The use of this technique is ideally suited for the rapid prototyping of embedded microelectronic components and systems while allowing the overall circuit design and layout to be easily modified or adapted to any specific application or form factor. This paper describes the laser direct-write process as applied to the forward transfer of microelectronic devices.
CXCL13 activation of c-Myc induces RANK ligand expression in stromal/preosteoblast cells in the oral squamous cell carcinoma tumor–bone microenvironment

CXC chemokine ligand-13 (CXCL13) has been implicated in oral squamous cell carcinoma (OSCC) tumor progression and osteolysis. The tumor necrosis factor family member RANKL (receptor activator of NF-κB ligand), a critical bone resorbing osteoclastogenic factor, has an important role in cancer invasion of bone/osteolysis. Here, we show high-level expression of CXCL13 in primary human OSCC tumor specimens; however, human bone marrow-derived stromal (SAKA-T) and murine preosteoblast (MC3T3-E1) cells produce at very low level. Recombinant CXCL13 (0-15 ng/ml) dose dependently induced CXCR5 expression in SAKA-T and MC3T3-E1 cells. Conditioned media obtained from OSCC cell lines increased the RANKL expression and an antibody against the CXCL13 specific receptor, CXCR5 markedly decreased RANKL expression in these cells. Furthermore, CXCL13 increased hRANKL-Luc promoter activity. Superarray screening identified c-Myc and NFATc3 transcription factors upregulated in CXCL13-stimulated SAKA-T cells. Immunohistochemical analysis of OSCC tumors that developed in athymic mice demonstrated RANKL and NFATc3 expression in tumor and osteoblast cells, however, showed p-c-Myc expression specific to osteoblastic cells at the tumor-bone interface. We further identified NFATc3 expression, but not c-Myc activation in primary human OSCC tumor specimens compared with adjacent normal tissue. Also, CXCL13 significantly increased p-ERK1/2 in SAKA-T and MC3T3-E1 cells. siRNA suppression of c-Myc expression markedly decreased CXCL13-induced RANKL and NFATc3 expression in preosteoblast cells. Chromatin-immuno precipitation assay confirmed p-c-Myc binding to the hRANKL promoter region. In summary, c-Myc activation through CXCL13-CXCR5 signaling axis stimulates RANKL expression in stromal/preosteoblast cells. Thus, our results implicate CXCL13 as a potential therapeutic target to prevent OSCC invasion of bone/osteolysis.
The novel transcriptional regulator SA1804 Is involved in mediating the invasion and cytotoxicity of Staphylococcus aureus

The two-component regulatory system, SaeRS, controls expression of important virulence factors, including toxins and invasins, which contribute to the pathogenicity of Staphylococcus aureus. Previously, we conducted a transcriptomics study for identification of SaeRS regulon and found that inactivation of SaeRS dramatically enhances the transcription of a novel transcriptional regulator (SA1804). This led us to question whether SA1804 is involved in bacterial pathogenicity by regulating the expression of virulence factors. To address this question, we created sa1804, saeRS, and sa1804/saeRS double deletion mutants in a USA300 community-acquired MRSA strain, 923, and determined their impact on the pathogenicity. The deletion of sa1804 dramatically increased the cytotoxicity and enhanced the capacity of bacteria to invade into the epithelial cells (A549), whereas the deletion of saeRS eliminated the cytotoxicity and abolished the bacterial ability to invade into the epithelial cells. Moreover, the double deletions of sa1804 and saeRS appeared a similar phenotype with the saeRS null mutation. Furthermore, we determined the regulatory mechanism of SA1804 using qPCR and gel-shift approaches. Our data indicate that the novel virulence repressor SA1804 is dependent on the regulation of SaeRS. This study sheds light on the regulatory mechanism of virulence factors and allows for us further elucidate the molecular pathogenesis of S. aureus.
General Solutions of Anisotropic Laminated Plates

Anisotropic laminates with bending-stretching coupling possess eigensolutions that are analytic functions of the complex variables x + μ k y, where the eigenvalues μ k and the corresponding eigenvectors are determined in the present analysis, along with the higher-order eigenvectors associated with repeated eigenvalues of degenerate laminates. The analysis and the resulting expressions are greatly simplified by using a mixed formulation involving a new set of elasticity matrices A*, B*, and D*. There are Il distinct types of laminates, each with a different expression of the general solution. For an infinite plate with an elliptical hole subjected to uniform in-plane forces and moments at infinity. closed-form solutions are obtained for all types of anisotropic laminates in terms of the eigenvalues and eigenevctors.
Biostatistics and Bayes

Attitudes of biostatisticians toward implementation of the Bayesian paradigm have changed during the past decade due to the increased availability of computational tools for realistic problems. Empirical Bayes' methods, already widely used in the analysis of longitudinal data, promise to improve cancer incidence maps by accounting for overdispersion and spatial correlation. Hierarchical Bayes' methods offer a natural framework in which to demonstrate the bioequivalence of pharmacologic compounds. Their use for quantitative risk assessment and carcinogenesis bioassay is more controversial, however, due to uncertainty regarding specification of informative priors. Bayesian methods simplify the analysis of data from sequential clinical trials and avoid certain paradoxes of frequentist inference. They offer a natural setting for the synthesis of expert opinion in deciding policy matters. Both frequentist and Bayes' methods have a place in biostatistical practice.
Immobilization of Desulphovibrio desulphuricans: cell-associated hydrogenase in beaded matrices

Abstract The immobilization of the hydrogenase (cytochrome c 3 hydrogenase, hydrogen: ferricytochrome c 3 oxidoreductase, EC 1.12.2.1) activity associated with Desulphovibrio desulphuricans whole cells is described. The periplasmic hydrogenase was prevented from leaking from the cells by glutaraldehyde treatment. This modification left the hydrogenase activity of the cells unchanged. The resulting whole-cell preparation was then immobilized in beaded gels formed by either calcium alginate or low temperature radiation-polymerized polyacrylamide(s). The alginate matrix was used to study the effect of bead diameter and retention of hydrogenase activity after immobilization. Polyacrylamide matrices were used to study the effects of immobilization on hydrogenase activity vs. pH profiles and also matrix charge effects on enzymatic activity and long-term storage.
A full finite-range CCBA analysis of the 118Sn(p, t) 116Sn reaction

Abstract Exact finite-range coupled-channel Born approximation calculations, using a microscopic form factor, were performed for the 118 Sn(p, t) 116 Sn reaction. Good agreement with experiment was obtained, both in the shape of the angular distributions and the relative magnitudes of the cross sections. Corresponding results using a zero-range approximation were found to agree much more poorly with experiment.
A PDP-11/45 Program for Playing N-Person Characteristic Function Games

NPER II is an on-line PDP-11/45 computer program for studying bargaining and coalition formation processes within the framework of n-person games in characteristic function form. The extensive vocabulary of the program and its mode of operation are presented nontechnically, followed by an examination of a protocol from a sample four-person game. Improvements over a previous version of the program and applications to other experimental paradigms investigating coalition formation and bargaining are discussed in the last two sections of the paper.
Axiomatizable and nonaxiomatizable congruence prevarieties

If \({\mathcal{V}}\) is a variety of algebras, let \({\mathcal{L}}(\mathcal{V})\) denote the prevariety of all lattices embeddable in congruence lattices of algebras in \({\mathcal{V}}\). We give some criteria for the first-order axiomatizability or nonaxiomatizability of \({\mathcal{L}}(\mathcal{V})\). One corollary to our results is a nonconstructive proof that every congruence n-permutable variety satisfies a nontrivial congruence identity.
Assignment of Protoheme Resonance Raman Spectrum by Heme Labeling in Myoglobin

Resonance Raman (RR) spectra are reported for myoglobin reconstituted with seven heme isotopomers which are labeled with 15N and meso-D4 in the porphyrin skeleton or at the vinyl and propionate substituents. The RR bands are assigned to the porphyrin in-plane and out-of-plane modes as well as to the internal vibrations of substituents on the basis of the observed isotope shifts. The issue of vinyl substituent effects is revisited, and bands are assigned to the 2- or 4-vinyl group from selective deuteration shifts. Contributions of the aliphatic propionate groups are also revealed in the RR spectrum. The protein influence on the heme structure is reflected in the activation of several out-of-plane modes in the low-frequency region.
The centrality of process

This paper makes the case for the pervasiveness, centrality, and criticality of strategy process, with the aim of increasing support for strategy process research and a greater recognition of its importance. We argue this on the basis of a framework that illustrates the fundamental property and characteristic traits of strategy process, suggesting that strategy process is at the heart of such popular topics as dynamic capabilities.
Surface segregation in an FeCrP alloy

Pour etudier les tendances de l'interaction de Cr+P, on observe par spectrometrie Auger la segregation de surface dans l'alliage Fe-1% Cr-0,03%P chauffe a 400 et 650 C. On observe les interactions de Cr+N et Cr+S mais aucune de Cr+P
Older women in retirement communities: Perceptions of recreation and leisure

Seven focus groups were conducted to examine leisure perceptions of 44 Anglo women, age 64 and older, living in retirement communities. Participants reported extensive involvement in numerous activities throughout their lives. Their comprehension of recreation and leisure mirrored many of the traditional definitions. Recreation was viewed as refreshment, renewal, and reward for work. Some described feelings of guilt when idle. Others characterized recreation as activity requiring effort. Overall, the women believed that recreation was a positive experience. Leisure was perceived as freedom from purpose and demands. Most also perceived leisure to be activity and positive. The discerning difference between recreation and leisure was that leisure was without rules, structure, or effort. Activity participation was essential to well‐being. Focus groups were found to be useful in facilitating discussion of recreation and leisure with this study group. A composite term, enjoyable activities, shows potential for ...
Hibernating bears as a model for preventing disuse osteoporosis

The hibernating bear is an excellent model for disuse osteoporosis in humans because it is a naturally occurring large animal model. Furthermore, bears and humans have similar lower limb skeletal morphology, and bears walk plantigrade like humans. Black bears (Ursus americanus) may not develop disuse osteoporosis during long periods of disuse (i.e. hibernation) because they maintain osteoblastic bone formation during hibernation. As a consequence, bone volume, mineral content, porosity, and strength are not adversely affected by annual periods of disuse. In fact, cortical bone bending strength has been shown to increase with age in hibernating black bears without a significant change in porosity. Other animals require remobilization periods 2-3 times longer than the immobilization period to recover the bone lost during disuse. Our findings support the hypothesis that black bears, which hibernate for as long as 5-7 months annually, have evolved biological mechanisms to mitigate the adverse effects of disuse on bone porosity and strength.
Ethylene formation from methional

Abstract The biosynthetic precursor of ethylene is 3-methylthiopropanal (methional). It has been claimed that hydroxyl (HO·) radicals are involved in this biosynthetic sequence, and that the production of ethylene from methional can be used as a specific probe for the presence of the HO· radical. We have now shown, however, that a variety of organic radicals lead to the production of ethylene from methional. Clearly this reaction cannot be used to test for the presence of HO· radicals, and the mechanism for the conversion of methional to ethylene will have to be reexamined.
The mobile photographic stress meter (MPSM): a new way to measure stress using images

Stress is an important aspect of human psychology. Many measures of stress have been developed over the years, but different issues exist for most of these measures. This study introduces the Mobile Photographic Stress Meter (MPSM), a new way to measure stress in which a user simply selects an image that best captures his or her stress level. Such a tool allows researchers to quickly measure stress in real time and in natural environments less onerous for the user. Our results show that MPSM is a valid measure of stress. Users find it easy and actually enjoyable to use. Our results also show that MPSM is strongly correlated with the Perceived Stress Scale, a validated multi-item stress scale. The correlation has an r-value of 0.5559 and a p-value of less than 0.001. We conclude that MPSM can be applied effectively in research experiments and advance the research on stress.
A light-gated synthetic ion channel.

A gated synthetic ion channel with β-cyclodextrin as the pore and azobenzene as the gate is reported. Irradiation converts a tethered trans-azobenzene to cis-azobenzene which likely transforms the channel from a self-inclusion complex to a dissociated structure. This transformation results in an increase in anion transport and a decrease in cation transport across a phospholipid vesicle membrane.
Establishment and application of the 0/45 reflectance factor scale over the shortwave infrared

This paper describes the establishment and application of the 0/45 reflectance factor scale in the shortwave infrared (SWIR) from 1100 to 2500 nm. Design, characterization, and the demonstration of a four-stage, extended indium-gallium-arsenide radiometer to perform reflectance measurements in the SWIR have been previously discussed. Here, we focus on the incorporation of the radiometer into the national reference reflectometer, its validation through comparison measurements, and the uncertainty budget. Next, this capability is applied to the measurement of three different diffuser materials. The 0/45 spectral reflectance factors for these materials are reported and compared to their respective 6/di spectral reflectance factors.
Opening the Preferences: A Socio-Economic Research Agenda

Economists tend to view preferences as given, either a subject to be studied by other disciplines or as constant, and universal, and hence as not requiring study. These assumptions allow economists to ignore preferences in most of their analyses, to treat them as a closed book. However, in the face of serious difficulties in explaining and in predicting major segments of economic behavior some economists expressed an interest in integrating economic analysis with that of other social sciences (Thurow, 1983, especially p. 219; Dunlop, 1977).
T. B. Dozeman’s Revision of Exod 2:11-13: A Critique

AbstractThis article challenges two planks of T. B. Dozeman’s interpretation of Exod 2:11-13: (1) the Egyptian whom Moses slew, first killed the Hebrew; (2) in the following scene, one Hebrew murdered the other.
Membrane Uncoating of Intact Enveloped Viruses

Experiments in the 1960s showed that Sendai virus, a paramyxovirus, fused its membrane with the host plasma membrane. After membrane fusion, the virus spontaneously "uncoated" with diffusion of the viral membrane proteins into the host plasma membrane and a merging of the host and viral membranes. This led to deposit of the viral ribonucleoprotein (RNP) and interior proteins in the cell cytoplasm. Later work showed that the common procedure then used to grow Sendai virus produced damaged, pleomorphic virions. Virions, which were grown under conditions that were not damaging, made a connecting structure between virus and cell at the region where the fusion occurred. The virus did not release its membrane proteins into the host membrane. The viral RNP was seen in the connecting structure in some cases. Uncoating of intact Sendai virus proceeds differently from uncoating described by the current standard model developed long ago with damaged virus. A model of intact paramyxovirus uncoating is presented and compared to what is known about the uncoating of other viruses.
Receptor Activator of NF-κB and Osteoprotegerin Expression by Human Microvascular Endothelial Cells, Regulation by Inflammatory Cytokines, and Role in Human Osteoclastogenesis *

The receptor activator of NF-κB (RANKL) is the essential signal required for full osteoclast (OC) development, activation, and survival. RANKL is highly expressed in areas of trabecular bone remodeling and inflammatory bone loss, is increased on marrow stromal cells or osteoblasts by osteotropic hormones or cytokines, and is neutralized by osteoprotegerin (OPG), a soluble decoy receptor also crucial for preventing arterial calcification. Vascular endothelial cells (VEC) are critically involved in bone development and remodeling and influence OC recruitment, formation, and activity. Although OCs develop and function in close association with bone VEC and sinusoids, signals mediating their interactions are not well known. Here, we show for the first time that human microvascular endothelial cells (HMVEC) express transcripts for both RANKL and OPG; inflammatory cytokines tumor necrosis factor-α and interleukin-1α elevate RANKL and OPG expression 5–40-fold in HMVEC (with an early OPG peak that declines as RANKL rises), and RANKL protein increases on the surface of tumor necrosis factor-α-activated HMVEC. Cytokine-activated HMVEC promoted the formation, fusion, and bone resorption of OCs formed in co-cultures with circulating human monocytic precursors via a RANKL-mediated mechanism fully antagonized by exogenous OPG. Furthermore, paraffin sections of human osteoporotic fractured bone exhibited increased RANKL immunostaining in vivo on VEC located near resorbing OCs in regions undergoing active bone turnover. Therefore, cytokine-activated VEC may contribute to inflammatory-mediated bone loss via regulated production of RANKL and OPG. VEC-derived OPG may also serve as an autocrine signal to inhibit blood vessel calcification.
Secondary Flow in Mildly Sinuous Channel

Most analytical models of the flow and bed topography in sinuous channels include the assumption that the secondary flow is locally adapted to channel curvature. Recently, Kitanidis and Kennedy (1984) and Ikeda and Nishimura (1986) have, however, established the existence of a phase lag between the two, induced by inertia, i.e., downstream convective acceleration of the secondary flow. The analysis of Ikeda and Nishimura (1986), nevertheless, includes an unverified assumption. Herein a more rigorous derivation of the effect is obtained with a minimum of assumptions. The predicted lag appears to be sufficiently small to warrant neglect in natural channels. The theory predicts much higher values in many experimental channels, in agreement with data. The reason for this is that a scaled dimensionless meander wave number r, found to be order‐one in natural channels, is found to be an order of magnitude higher in many laboratory meandering flumes.
Learning Kinematic Constraints in Laparoscopic Surgery

To better understand how kinematic variables impact learning in surgical training, we devised an interactive environment for simulated laparoscopic maneuvers, using either 1) mechanical constraints typical of a surgical "box-trainer" or 2) virtual constraints in which free hand movements control virtual tool motion. During training, the virtual tool responded to the absolute position in space (Position-Based) or the orientation (Orientation-Based) of a hand-held sensor. Volunteers were further assigned to different sequences of target distances (Near-Far-Near or Far-Near-Far). Training with the Orientation-Based constraint enabled much lower path error and shorter movement times during training, which suggests that tool motion that simply mirrors joint motion is easier to learn. When evaluated in physically constrained (physical box-trainer) conditions, each group exhibited improved performance from training. However, Position-Based training enabled greater reductions in movement error relative to Orientation-Based (mean difference: 14.0 percent; CI: 0.7, 28.6). Furthermore, the Near-Far-Near schedule allowed a greater decrease in task time relative to the Far-Near-Far sequence (mean -13.5 percent, CI: -19.5, -7.5). Training that focused on shallow tool insertion (near targets) might promote more efficient movement strategies by emphasizing the curvature of tool motion. In addition, our findings suggest that an understanding of absolute tool position is critical to coping with mechanical interactions between the tool and trocar.
Advances in finite-difference time-domain (FD-TD) numerical modeling techniques for Maxwell's equations

Prompted to a significant degree by perceived limitations of the method of moments, there has been an explosion of interest in the engineering electromagnetic wave community in direct solutions of the fundamental Maxwell's curl equations on space grids in either the time or frequency domain. The finite-difference time domain (FD-TD) method introduced by Yee (1966), has received perhaps the most attention during this period because of its simplicity and robustness. Advances in FD-TD modeling techniques have further improved its modeling accuracy and expanded its range of applications. These advances are succinctly summarized under the sections: 1. Berenger perfectly matched layer absorbing boundary condition; 2. Dispersive, nonlinear, and gain material models; 3. Active circuit device models; 4. Planar unstructured meshes; and 5. Software development for massively parallel computers.
Effect of Aluminide Particle Distribution on the High Temperature Crack Growth Characteristics of a Co-Ni-Fe Superalloy

Inconel 783{reg_sign} is an oxidant-resistant, controlled coefficient of thermal expansion, cobalt-nickel-iron-based superalloy. The matrix ({gamma}) is FCC and can be strengthened by coherent strengthening precipitates ({gamma}{prime}). It has been shown that an aluminum content greater than 5 wt% leads to the formation of body-centered aluminide ({beta}) particles and improved resistance to stress accelerated grain boundary oxygen (SAGBO) embrittlement relative to other low-expansion superalloys. The study described below was undertaken to determine the role of the {beta} phase during creep crack growth, and how its distribution affects the alloy`s SAGBO resistance. Aging of alloy 783 to produce a continuous grain boundary film of {beta} phase results in reduced creep crack growth rates at 538 C compared to heat treatments which do not result in a continuous film. Oxidation studies indicate that the {beta} phase is oxidation resistant and hence may cause increased resistance to SAGBO.
Regulation of histone gene expression in HeLa S3 cells

Publisher Summary Histone genes represent a moderately repeated set of genes in human cells. To study the organization and regulation of human histone genes, we have characterized a series of recombinant lambda Charon 4A phage containing genomic human histone sequences (designated λHHG). Our analyses indicate that human histone genes are clustered but are not organized in a simple tandem repeat pattern as is observed for several lower eukaryotes. For example, several of the human genomic fragments we have isolated contain two each of segments coding for H3 and H4 histones. Of particular interest with respect to organization and expression of the human histone genes is the presence of at least seven different H4 histone mRNAs associated with polysomes of S phase HeLa cells. At least three of the HeLa H4 histone mRNAs are products of distinct genes and two H4 histone genes in the same genomic fragment code for different H4 mRNAs. We have used our cloned human histone genes to examine the regulation of histone gene expression in human cells. Though it is generally agreed that histone protein synthesis in HeLa cells is restricted to the S phase of the cell cycle, and therefore parallels DNA replication, both transcriptional and post-transcriptional levels of control have been postulated. By probing electrophoretically fractionated, filter-immobilized RNAs with several cloned genomic human histone sequences representing different histone gene clusters, we have assessed the steady state levels of histone RNAs in the nucleus and cytoplasm of G1 and S phase HeLa S3 cells. The representation of histone mRNA sequences in G1 compared with S phase cells was less than 1% in the cytoplasm and approximately 1% in the nucleus. These data are consistent with control occurring primarily at the transcriptional level, but we cannot dismiss the possibility that regulation of histone gene expression is, to some extent and/or under some biological circumstances, mediated post-transcriptionally. If histone gene transcription does occur in G1, the RNAs must either be rapidly degraded or be transcribed to a limited extent compared with S phase. An unexpected result was obtained when a northern blot of cytoplasmic RNA from G1 and S phase cells was hybridized with λHHG41 DNA (containing H3 and H4 genomic human histone sequences). This clone hybridizes with histone mRNAs present in S phase cytoplasmic RNA, but also hybridizes with a G1 cytoplasmic RNA approximately 330 nucleotides in length. This RNA, present in the cytoplasm of HeLa cells predominantly in the G1 phase of the cell cycle, is not similar in size or nucleotide sequence to known histone RNAs. The possibility of prokaryotic-like organization and regulation of human histone genes is discussed.
Effects of applied NaCl on Opuntia humifusa

Plant morphology in the field in Virginia, USA, and growth responses to applied NaCl in a glasshouse were determined for two populations of Opuntia humifusa (Rafinesque) Rafinesque, one from an inland site and the other from the marine strand, which differed in potential exposure to salinity. Cladode dimensions, plant height and rooting depth varied significantly between the populations. Application of NaCl in 50 mM increments up to 400 mM every 3 days for 6 weeks caused the cladodes to decrease up to 30% in thickness, the decrease being about 20% more at 50 to 150 mM NaCl for plants from the inland site than from the marine strand. Inhibition by 150 mM NaCl of the maximum rate of net CO2 uptake and of the total CO2 uptake over a 24-h period was greater for the inland population. Growth, especially of roots, was inhibited by applied NaCl, with a decrease in biomass above 200 mM NaCl for plants from the inland site and not until 400 mM for those from the marine strand. Although the root Na+ level was the same for plants from the two populations, reaching a maximum of about 8 mg (g dry weight)−1 at 200 mM NaCl, the cladode Na+ level was two-fold higher for plants from the marine strand than from the inland site. Thus, exclusion of Na+ from the cladodes is not the reason for the greater NaCl tolerance of O. humifusa from the marine strand, which is a habitat that can experience periodic episodes of high salinity.
Lack of communication between LC2 light chain and the SH1 region of myosin S-1 studied by 19F-NMR.

Abstract Myosin subfragment-1 (S-1) which contains the LC2 light chain has been labelled with fluorine to allow an 19 F-NMR study of the coupling and energetics of structural changes in the myosin head. Two fluorine-containing reagents, N -4-(trifluoromethyl)phenyl iodoacetamide and N -3,5-di(trifluoromethyl)phenyl iodoacetamide, have been used to label the myosin heavy chain at the unusually reactive sulfhydryl-1 (SH 1 ) position. The chemical shift of both reagents on S-1 is sensitive to a structural transition in the region of SH 1 which occurs upon increasing the temperature from 0°C to 35°C. The midpoint of the transition in both papain and chymotryptic S-1 is at approximately 11°C at pH 7 (0.1 M CKI). The temperature dependence of the chemical shift may be fit assuming a two-state equilibrium where ΔG °′( T ) = 101–110 T + 0.386 T 2 (where T is the temperature in Kelvin). Both ΔH °′( T ) and ΔS °′( T ) have a small temperature dependence from 0 to 35°C: at 20°C, ΔH °′( T ) = −33 kcal/mol. ΔS °′( T ) = −116 e.u. and ΔC P = −226 cal/mol per deg (pH 7.0, 0.1 M KCl). The NMR data indicate that the presence of the LC2 light chain in papain S-1 does not modify the structure of S-1 in the vicinity of SH 1 , nor does it modify the energetics of the structural transition from that seen in its absence with chymotryptic S-1. The presence of calcium which is bound by the LC2 of papain S-1 also does not alter the energetics of the transition. Thus it would appear that the LC2 light chain (on myosin S-1) does not participate in the two-state transition, nor does it interact strongly with regions of the heavy chain which participate in the transition.
Polygalacturonase isozyme 2 binding and catalysis in cell walls from tomato fruit: pH and β‐subunit effects

The catalytic activity of endopolygalacturonase (PG, EC 3.2.1.15) against pectic polymers in vitro is typically not expressed in vivo. In the present study, the binding and catalytic properties of PG isozyme 2 and the influence of the β-subunit protein were investigated in cell walls prepared from tomato fruit expressing an antisense gene to the β-subunit protein. Cell walls prepared from mature-green fruit were employed for binding and assay of PG2. Walls were provided with rate-limiting quantities of purified PG2 and incubated at 100 mM KCl, pH 4.5, or 25 mM KCl, pH 6.0. Cell walls of both β-subunit antisense and wild-type fruit retained comparable quantities of added PG2. The release of pectin from PG2-loaded walls was proportional to the quantity of added enzyme, consistent with a finite catalytic capacity of individual PG proteins. β-Subunit-antisense cell walls released 2- to 3-fold higher levels of pectin in response to PG2 than did wild-type walls. Cell walls incubated at pH 6.0 released lower quantities and showed less extensive depolymerization of pectins than did walls incubated at pH 4.5. Pectins recovered from ripe fruit were similar in size distribution to polymers released by PG2 at pH 6.0, indicating that pH can influence both quantitative and qualitative aspects of pectin metabolism and may be responsible for the restricted hydrolysis of pectins in vivo. Molecular mass differences were not evident in the polymers rendered freely soluble in response to PG2-mediated hydrolysis of β-subunit-antisense compared with wild-type cell walls. The solubilization of pectin from cell walls was not the sole indicator of the extent of PG-mediated cell wall hydrolysis. Hydrolytic modifications were also evident in a pectic fraction extracted from postcatalytic cell walls with 50 mM CDTA (trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid), and were more extensive for the β-subunit-antisense cell walls compared with the wild-type walls. Pectic polymers derived from ethanol insoluble-powders showed molecular mass downshifts during ripening but differences between the β-subunit-antisense and wild-type fruits were not observed.
Sodium Lactate Affects Pathogens in Cooked Beef

Cooked, quartered beef top rounds containing either 1, 2, 3 or 4% sodium lactate were aseptically sampled and slice sections were inoculated with Listeria monocytogenes (ATCC 43256), Staphylococcus aureus (ATCC 27154), Salmonella typhimurium (ATCC 13311), Clostridium perfringens (ATCC 12924), or Escherichia coli O157:H7 (ATCC 43895). Inoculated slices were stored at 10°C for 0. 7. 14. 21 or 28 days.‘Three and 4% sodium lactate generally displayed lim-ited proliferation of S. typhimurium, L. monocytogenes and E. coli O157:H7 when compared with control roasts (0% sodium lactate) and roasts containing 2% sodium lactate.
Methodology for simulating 1/f noise characteristics in the time domain for infrared focal plane applications

A computer code for a 1/f noise generator has been developed and is used to produce long sequences of temporal 1/f noise. This generator, which was developed in 1971, avoids the large memory requirements associated with other methods that have been used to produce extended records of 1/f noise. The power spectral density (PSD) of a sequence of such noise is calculated to verify its 1/f character. Noise that has a PSD of the form 1/f(alpha ), where (alpha) is a non-integer exponent, may also be generated. As an example, the temporal 1/f noise current from MWIR HgCdTe photodetectors is simulated.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Two types of pyruvate kinase in schistosomes and filariae.

Abstract 1. 1. Pyruvate kinase (PK) from the trematode Schistosoma mansoni closely resembles PK from rabbit muscle in its response to various purine and pyrimidine nucleoside diphosphates and divalent cations, in its insensitivity to activation by FDP and relative insensitivity to inhibition by ATP and in its somewhat higher affinity for PEP. 2. 2. PK's from the filarial nematodes Litomosoides carinii and Dirofilaria immitis closely resemble PK from rabbit liver in the pattern of their substrate and cofactor specificities, by being strongly activated by FDP and inhibited by ATP, and by showing a relatively lower affinity for PEP. 3. 3. The properties of PK from S. mansoni miracidia were indistinguishable from those of PK from the adult forms, and this was also the case for the PK's from D. immitis microfilariae and adults. 4. 4. The molecular weights of PK's from S. mansoni , D. immitis and rabbit muscle were all around 270,000±10 per cent.
Smoothing spline models for the analysis of nested and crossed samples of curves

Abstract We introduce a class of models for an additive decomposition of groups of curves stratified by crossed and nested factors, generalizing smoothing splines to such samples by associating them with a corresponding mixed-effects model. The models are also useful for imputation of missing data and exploratory analysis of variance. We prove that the best linear unbiased predictors (BLUPs) from the extended mixed-effects model correspond to solutions of a generalized penalized regression where smoothing parameters are directly related to variance components, and we show that these solutions are natural cubic splines. The model parameters are estimated using a highly efficient implementation of the EM algorithm for restricted maximum likelihood (REML) estimation based on a preliminary eigenvector decomposition. Variability of computed estimates can be assessed with asymptotic techniques or with a novel hierarchical bootstrap resampling scheme for nested mixed-effects models. Our methods are applied to me...
Effects of nitric oxide synthase inhibition on the muscle blood flow response to exercise in rats with heart failure

Objective: The aim of this study was to investigate whether the role of nitric oxide (NO) in regulating blood flow (BF) to working skeletal muscle is impaired in chronic heart failure (CHF). Methods: The effect of N G-nitro-l-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, was studied in conscious rats with and without CHF due to myocardial infarction (MI). BF to the hindquarter musculature was measured with radiolabelled microspheres during exercise after 4 min of treadmill running (10% grade, 20 m/min) before and after L-NAME (20 mg/kg i.a.) administration. Results: Before L-NAME administration, BF measured in the total hindquarter musculature was less ( P < 0.05) during exercise in rats with a large MI (MI size; 44 ± 2% of the left ventricular endocardial circumference; n = 8) when compared with sham-operated rats (SHAM; n = 10) and rats with a small MI (MI size; 25 ± 4%; n = 5). The BF measured during exercise following L-NAME administration was similar between the 3 groups. Of the 28 individual hindquarter muscles, BF was reduced in 23 and 19 muscles following the administration of L-NAME for the SHAM rats and rats with a small MI, respectively. In comparison, BF was reduced to only 4 of 28 muscles in rats with a large MI. Conclusions: These results suggest that the contribution of the NO pathway to the hyperaemic BF responses found in the hindquarter muscles during exercise could be attenuated in rats with CHF. This attenuation of the NO pathway may be associated with the impairment of skeletal muscle BF distribution during exercise in CHF.