cssi/SciSciGPT-SciSciNet huggingface dataset:
A Theoretical Model of Stretch-Induced Stress Fiber Remodeling

Cyclic stretching of endothelial cells (ECs), such as occurs in arteries during the cardiac cycle, induces ECs and their actin stress fibers to orient perpendicular to the direction of maximum stretch. This perpendicular alignment response is strengthened by increasing the magnitudes of stretch and cell contractility (1). The actin cytoskeleton is a dynamic structure that regulates cell shape changes and mechanical properties. It has been shown that actin stress fibers are ‘prestretched’ under normal, non-perturbed, conditions (2), consistent with the ideas of ‘prestress’ that have motivated tensegrity cell models (3). It has also been shown that ‘tractional forces’ generated by cells at focal adhesions tend to increase proportionately with increasing focal adhesion area, thus suggesting that cells tend to maintain constant the stress borne by a focal adhesion (4). By implication, this suggests that cells try to maintain constant the stress in actin stress fibers. Thus, it seems that cells reorganize or turnover cytoskeletal proteins and adhesion complexes so as to maintain constant a preferred mechanical state. Mizutani et al. (5) referred to this as cellular tensional homeostasis, although they did not suggest a model or theory to account for this dynamic process.Copyright © 2008 by ASME
Acute and chronic effects of nicotine on synthesis and storage of catecholamines in the rat adrenal medulla.

Abstract Nicotine (1 mg/kg or 10 mg/kg) was administered twice daily to rats and the adrenals were analyzed for catecholamines (CA), tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH), and for the ability of isolated storage vesicles to incorporate 3H-epinephrine. Four hours after the first dose, there were few alterations at 1 mg/kg, but at 10 mg/kg, there was 30% depletion of CA, accompanied by a slight reduction in DBH and a decline in the number of functional vesicles (determined by uptake). Chronic administration of either dose produced elevations in both TH and DBH; at 10 mg/kg, CA levels and functional vesicles continued to decline for at least 4 days, but were at or above normal after 2 weeks of treatment. At 1 mg/kg, CA levels were never significantly below normal, and were elevated after 2 weeks. After 2 weeks at either dose level, a defect appeared in the abilities of vesicles to incorporate exogenous epinephrine relative to endogeneous CA content; this alteration also appeared if nicotine was discontinued. These data suggest that chronic nicotine administration can produce long-term alterations in CA release, synthesis and storage, and that these alterations can occur even at a dose which has little or no acute effect.
Protein Kinase A Catalyzed Phosphorylation of Cardiac Myosin Binding Protein C Decreases Calcium Sensitivity of Force and Increases Cross-Bridge Cycling Kinetics in Murine Myocardium

At the myofilament level, increases in cardiac output in response to increased sympathetic tone is achieved via protein kinase A (PKA)-mediated phosphorylation of cardiac myosin binding protein C (cMyBP-C) and cardiac troponin I (cTnI). However, despite the physiological importance of β-adrenergic stimulation in maintaining cardiac performance, the respective roles of cMyBP-C and cTnI phosphorylations in the myofibrillar force response of working myocardium are not completely understood. Using transgenic mouse lines either (1) expressing mutant non-phosphorylatable cTnI (cTnIala5) or (2) expressing cTnIala5 on a cMyBP-C null background (cMyBP-C-/-/cTnIala5), we assessed the calcium sensitivity of force (pCa50) and the rate of force redevelopment (ktr) in skinned myocardial preparations following treatment with PKA and/or reconstitution with purified recombinant cMyBP-C. Before mechanical measurements, all preparations were treated with 2,3-butanedione monoxime (BDM) to reduce regulatory light chain (RLC) phosphorylation to near zero. In cTnIala5 myocardium, PKA phosphorylation of cMyBP-C resulted in a decrease in pCa50 and an increase in ktr. However, no changes in either variable were observed in cMyBP-C-/-/cTnIala5 myocardium in response to PKA treatment. Following reconstitution of cMyBP-C-/-/cTnIala5 myocardium with cMyBP-C, ktr decreased to the values observed in cTnIala5 myocardium, demonstrating that incorporation of cMyBP-C slowed the rates of cross-bridge attachment and transitions to strongly bound, force generating states. Subsequent treatment of reconstituted cMyBP-C-/-/cTnIala5 myocardium with PKA produced a rightward shift in pCa50 and an increase in ktr. Together, these results suggest that in the absence of cTnI phosphorylation (and RLC phosphorylation), PKA phosphorylation of cMyBP-C decreases calcium sensitivity of force and speeds cross-bridge cycling kinetics in murine myocardium.
X-ray microtomography: three-dimensional reconstruction methods for x-ray microscopy of biological samples

Biological soft x-ray microscopy using x-ray optics and synchrotron sources has made possible quantitative, element-specific imaging of whole cells in aqueous media at significantly higher resolutions than those of conventional visible light methods. Tomographic reconstruction has been proposed as a means to realize the full potential of the method for viewing thick objects whose structures would otherwise be superimposed in single view projections. The authors present an iterative tomographic reconstruction algorithm, using a regularized weighted least squares objective function, accelerated with the conjugate gradient approach, and modified for the problem of transmission tomography with correction of blurring by an instrumental point spread function. The non-negativity constraint is implemented using a preconditioner. We show by computer simulations that reconstructions that meet realistic and acceptable goals for spatial and density resolution should be achievable at doses compatible with the structural integrity of biological samples at the specific resolution.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Cutaneous low-dose radiation increases tissue vascularity through upregulation of angiogenic and vasculogenic pathways.

Background/Aims: Neovascularization involves angiogenesis and vasculogenesis mediated by cytokines and soluble chemokines. The predominant stimulus is ischemia, however, recent data
Single Unit Activity in the Rat Superior Colliculus During Reward Magnitude Task Performance

Long-Evans hooded rats were trained to run an alternation pattern in a t-maze with low reward (1 pellet) in the food cup of one arm and high reward (3 pellets) in the food cup of the other arm. Single units in the intermediate and deep layers of the superior colliculus were recorded using moveable microelectrodes. Most units showed activity that was associated with food retrieval, with a phasic increase in activity either upon the cessation of running or upon the insertion of the snout into the food cup. Some units (16%) showed different activity patterns upon retrieval of the two magnitudes of reward. Although 70% of the units showed either unimodal or multimodal sensory sensitivity, usually in response to tactile stimulation of the snout, this property was not related to activity associated with food retrieval. These data support previous observations that cells in the rat SC exhibit activity related to food retrieval, and indicate that for some of these neurons the coding reflects the characteristics of the reward stimulus.
Macrophage development: III. Transformation of pulmonary macrophages from precursors in fetal lungs and their later maturation in organ culture

The fate of macrophage precursors residing in 14-day prenatal rat lungs was followed in organ cultures to obtain a detailed, ultrastructurally resolved picture of the sequence and timing of events accompanying their transformation into typical pulmonary macrophages. Cultures were examined at close intervals during the first day (1, 2, 3, 4, 6, 9, 12, 15, 18, and 24 hr) and at wider intervals thereafter (2, 4, 5, 7, 9, and 13 days) to yield a developmental series of cells identified as in the macrophage line based on binding of peroxidase-coupled isolectin B4 of Griffonia simplicifolia (GSA I-B4) to cell membranes and on negligible content of peroxidase-positive granules in the cytoplasm. Organ culturing stimulated virtually all precursors to develop into macrophages. GSA-positive cells in explants occurred outside vessels in pulmonary connective tissue, and at the outset none were typical macrophages: 71% were angular cells, resembling unlabeled mesenchymal cells around them, 16% were undifferentiated leukocytes, and the remainder were irregularly shaped cells with few vacuoles intermediate between the preceding and the macrophages. During the first 12 hr in culture the proportion of angular cells and leukocytes fell to zero, and that of intermediate cells first rose, then receded. In the same interval the proportion of macrophages rose to 87.5%, and by 24 hr all GSA-positive cells were typical macrophages generally engorged with phagocytosed material; about 8 hr appear necessary for converting half the population. Notable ultrastructural changes during this period of transformation involved the centrioles and cytoskeleton, reflecting enhanced cell mobility and phagocytosis. A period of maturation followed, marked by disappearance of cellular debris from phagosomes and an increased prevalence of cells with elaborate lamellipodia. This accords with earlier work showing that macrophage Fc receptor density increases sharply during the first 24 hr, but elevated levels of histochemically demonstrable acid phosphatase appear only later. Mitotic activity was conspicuous in GSA-positive cells throughout both periods. 3H-thymidine labeling indices for precursors and macrophages, determined at six intervals between 1 hr and 24 hr, remained steady at approximately 34%, whereas indices of other categories of lung cells (GSA-negative stromal cells, pleural cells, and airway epithelium) began at this level but rapidly declined, indicating that the GSA-positive cells constitute a single population distinct from others in the lungs. Macrophages found outside the lung cultures after 4-5 days qualify as a mature population, but having migrated away from direct contact with the lung stroma, they survive only a week or two and no longer divide.
Systematic Evaluation of Bonding Strengths and Fracture Toughnesses of Adhesive Joints

A systematic experimental investigation to determine the shear, tensile, and fracture properties of adhesive joints with bonded same-materials (polymer-polymer) and bi-materials (metal-polymer) is reported. Full-field optical techniques including photoelasticity and coherent gradient sensing (CGS) are employed to record the stress development and failure in these adhesive joints. Five types of strong and weak adhesives are used in conjunction with five different types of materials [aluminum, steel, polymethylmethacrylate (PMMA), polycarbonate, and Homalite®-100] to produce a variety of bonded material systems. Weld-on®-10 and a polyester bonding consistently show higher tensile and shear bonding strengths. Bi-material systems in shear and fracture report lower properties than the same-material systems due to a higher property mismatch in the former. The resulting complete experimental data are expected to be immensely helpful to computational mechanists in simulating failure mechanics of adhesive joints.
Mechanisms of Radiation-Induced Viscous Flow: Role of Point Defects

Mechanisms of radiation-induced flow in amorphous solids have been investigated using molecular dynamics computer simulations. It is shown for a model glass system, CuTi, that the radiation-induced flow is independent of recoil energy between 100 eV and 10 keV when compared on the basis of defect production and that there is a threshold energy for flow of $\ensuremath{\approx}10\text{ }\mathrm{e}\mathrm{V}$. Injection of interstitial- and vacancylike defects induces the same amount of flow as the recoil events, indicating that point-defect-like entities mediate the flow process, even at 10 K. Comparisons of these results with experiments and thermal spike models are made.
Deformation and fracture under compressive loading in lamellar TiAl microstructures

Abstract A physically based micromechanical model is applied to study finite compressive deformation behaviour and the development of failure modes in polycrystalline fully lamellar and nearly lamellar microstructures. Orientation-dependent yielding of lamellar TiAl single crystals is specifically modelled. Finite-element computations show that deformation is inherently non-uniform in the lamellar microstructure, in accordance with results presented earlier by Kad, Dao and Asaro. Intergranular fracture initiation is found to be expected at small aggregate strains (i.e. strains less than 5%), while fracture initiated by internal buckling is found to be increasingly likely to occur at larger aggregate strains (i.e. strains larger than 5–10%). Internal buckling is found in lamellar TiAl crystals whose lamellae are initially nearly parallel to the compressive loading. A weak basal texture, normal to the compression axis, is developed at only 20% aggregate strain. Subtle variations in microstructural constitue...
SOHO: An unfortunate omission

The article by R. Schmidt et al. in the March 29 issue of Eos reports both the welcome news that the SOHO and Cluster payloads have been chosen and the surprising announcement that the planned solar wind and interplanetary magnetic field instruments were not selected for flight. For the reasons outlined below, we deeply regret this decision and urge the national agencies to alter this decision and rectify the situation. The solar wind is still very much an object of study. The source and energization of the solar wind is but poorly understood. The originally planned payload of SOHO provided the opportunity to study the solar surface in considerable detail while monitoring the solar wind at 1 AU and thereby leading to the solution of this mystery. No other present or planned mission will provide undisturbed solar wind data continuously or nearly so. If the Wind spacecraft of the International Solar-Terrestrial Physics (ISTP) project were used, it would be only by diverting it from its role of studying the extended foreshock region and of providing measurements of the solar wind on the streamlines that intersect the magnetosphere. Moreover, we need both spacecraft for these studies, the SOHO spacecraft for providing early warning or forecasting and the Wind spacecraft for monitoring near-Earth conditions for nowcasting. Not only the solar wind itself but also the solar wind control of magnetospheric activity are vital active research topics that require the highest-quality data sets.
CD33-specific chimeric antigen receptor T cells exhibit potent preclinical activity against human acute myeloid leukemia

Patients with chemo-refractory acute myeloid leukemia (AML) have a dismal prognosis. Chimeric antigen receptor T (CART) cell therapy has produced exciting results in CD19+ malignancies and may overcome many of the limitations of conventional leukemia therapies. We developed CART cells to target CD33 (CART33) using the anti-CD33 single chain variable fragment used in gemtuzumab ozogamicin (clone My96) and tested the activity and toxicity of these cells. CART33 exhibited significant effector functions in vitro and resulted in eradication of leukemia and prolonged survival in AML xenografts. CART33 also resulted in human lineage cytopenias and reduction of myeloid progenitors in xenograft models of hematopoietic toxicity, suggesting that permanently expressed CD33-specific CART cells would have unacceptable toxicity. To enhance the viability of CART33 as an option for AML, we designed a transiently expressed mRNA anti-CD33 CAR. Gene transfer was carried out by electroporation into T cells and resulted in high-level expression with potent but self-limited activity against AML. Thus our preclinical studies show potent activity of CART33 and indicate that transient expression of anti-CD33 CAR by RNA modification could be used in patients to avoid long-term myelosuppression. CART33 therapy could be used alone or as part of a preparative regimen prior to allogeneic transplantation in refractory AML.
T-antigen is not bound to the replication origin of the simian virus 40 late transcription complex.

Simian virus 40 tumor antigen (T-antigen) plays a central role in determining which gene is transcribed from viral DNA late in infection. Results from several studies have led to a model in which the binding of T-antigen to the viral origin of replication results in repression of transcription from the stronger early gene promoter and stimulation of transcription from the late gene promoter. We have tested this model by determining directly the occupancy of the T-antigen binding site in the origin of replication of the late transcription complex. Thus, viral transcription complexes were digested with Bgl I, a restriction enzyme that cuts in the viral replication origin. The enzyme cleaved 78(± 12)% of the late transcription complexes. Control experiments demonstrated that cleavage is blocked when T-antigen is bound to the origin site, that exogenously added T-antigen can bind to the site in the transcription complex, and that T-antigen is not released during isolation of the complex. These results indicate that most of the late transcription complexes do not have T-antigen bound to the origin site, and are therefore inconsistent with models that require this site to be occupied by T-antigen to maintain proper regulation of gene transcription late in infection.
Robust optimal design using a second-order tolerance model

In this paper we present a general, quantitative method for developing designs that are robust to variation in design variables and parameters. Variation is defined in terms of tolerances which bracket the expected deviation of uncertain quantities about nominal values. We specifically address the case where input variations are assumed to be random variables that are normally distributed. The method incorporates a second-order tolerance model as part of a nonlinear optimization process. The second-order tolerance model makes it possible to estimate the skewness of function distributions, which are modeled with a three-parameter gamma distribution. We apply the method to determine robust designs for 11 test cases that span a variety of problems; robustness is verified with Monte Carlo simulation. The method enables a designer to understand and account for the effects of tolerances, making it possible to build robustness into an engineering design.
Tracking inner city substance users from the emergency department: how many contacts does it take?

Background: Longitudinal studies of substance users report difficulty in locating and completing 12-month interviews, which may compromise study validity. Objectives: This study examined rates and predictors of contact difficulty and in-person follow-up completion among patients presenting with cocaine-related chest pain to an inner-city emergency department (ED). The authors hypothesize that less staff effort in contacting patients and lower follow-up rates would bias subsequent substance use analysis by missing those with heavier substance misuse. Methods: A total of 219 patients aged 19 to 60 years (65% males; 78% African American) with cocainerelated chest pain were interviewed in the ED and then in person at 3, 6, and 12 months. Demographics, substance use measures, and amount ⁄type of research staff contacts (telephone, letters, home visits, and locating patient during return ED visits) were recorded. Poisson and negative binomial regression analyses were conducted to predict quantity of patient contacts for the 12-month follow-up. Results: Interview completion rates at 3, 6, and 12 months were 78, 82, and 80%, respectively. Average contact attempts to obtain each interview were 10 at 3 months (range 3‐44), 8 at 6 months (1‐31), and 8 at 12 months (1‐49); 13% of patients required a home visit to complete the 12-month interview. Participants requiring more contact attempts by staff were younger and reported more frequent binge drinking at baseline (p < 0.05), but were less likely to meet criteria for substance abuse or dependence (p < 0.5), or to report prior mental health treatment (p < 0.05). Comparisons of parallel regressions predicting contact difficulty based on the entire sample, the low-effort group, and the difficult-to-reach group showed variation in findings. Conclusions: This study demonstrates that substantial staff effort is required to achieve adequate retention over 12 months of patients with substance misuse. Without these extensive efforts at follow-up, longitudinal analyses may be biased. ACADEMIC EMERGENCY MEDICINE 2008; 15:136‐143 a 2008 by the Society for Academic Emergency Medicine
An obesity educational intervention for medical students addressing weight bias and communication skills using standardized patients

In order to manage the increasing worldwide problem of obesity, medical students will need to acquire the knowledge and skills necessary to assess and counsel patients with obesity. Few educational intervention studies have been conducted with medical students addressing stigma and communication skills with patients who are overweight or obese. The purpose of this study was to evaluate changes in students' attitudes and beliefs about obesity, and their confidence in communication skills after a structured educational intervention that included a clinical encounter with an overweight standardized patient (SP). First year medical students (n = 127, 47% female) enrolled in a communications unit were instructed to discuss the SPs' overweight status and probe about their perceptions of being overweight during an 8 minute encounter. Prior to the session, students were asked to read two articles on communication and stigma as background information. Reflections on the readings and their performance with the SP were conducted prior to and after the encounter when students met in small groups. A newly constructed 16 item questionnaire was completed before, immediately after and one year after the session. Scale analysis was performed based on a priori classification of item intent. Three scales emerged from the questionnaire: negative obesity stereotyping (7 items), empathy (3 items), and counseling confidence (3 items). There were small but significant immediate post-intervention improvements in stereotyping (p = .002) and empathy (p < .0001) and a very large mean improvement in confidence (p < .0001). Significant improvement between baseline and immediate follow-up responses were maintained for empathy and counseling at one year after the encounter but stereotyping reverted to the baseline mean. Percent of students with improved scale scores immediately and at one year follow up were as follows: stereotyping 53.1% and 57.8%; empathy 48.4% and 47.7%; and confidence 86.7% and 85.9%. A structured encounter with an overweight SP was associated with a significant short-term decrease in negative stereotyping, and longer-term increase in empathy and raised confidence among first year medical students toward persons who are obese. The encounter was most effective for increasing confidence in counseling skills.
Global MHD modeling of the impact of a solar wind pressure change

[1] A sudden increase in the solar wind dynamic pressure compresses the magnetosphere and launches compressional waves into the magnetosphere. The global response of the magnetosphere, including the ionosphere and the location of the field-aligned current (FAC) generation, to a step increase in the solar wind density has been studied using a global three-dimensional adaptive MHD model. As the density increase propagated along the flanks of the magnetopause, a two-phased response was seen in the ionosphere. The first response was an increase in FACs near the polar cap. For this response we found the location of FACs to lie just inside the magnetosphere. The second response was an increase in FACs at lower latitudes. The increase in FACs was in the same direction as region 1 currents. For the second response we found the location of FACs to fall well within the magnetosphere.
Clinical Applications of Heart Rate Variability in the Triage and Assessment of Traumatically Injured Patients

Heart rate variability (HRV) is a method of physiologic assessment which uses fluctuations in the RR intervals to evaluate modulation of the heart rate by the autonomic nervous system (ANS). Decreased variability has been studied as a marker of increased pathology and a predictor of morbidity and mortality in multiple medical disciplines. HRV is potentially useful in trauma as a tool for prehospital triage, initial patient assessment, and continuous monitoring of critically injured patients. However, several technical limitations and a lack of standardized values have inhibited its clinical implementation in trauma. The purpose of this paper is to describe the three analytical methods (time domain, frequency domain, and entropy) and specific clinical populations that have been evaluated in trauma patients and to identify key issues regarding HRV that must be explored if it is to be widely adopted for the assessment of trauma patients.
Voting power when using preference ballots

In this paper we provide a generalized power index which gives a measurement of voting power in multi-candidate elections with weighted voting using preference ballots. We use the power index to compare the power of various players between an election using plurality and one using the Borda method. The power index is based upon the Banzhaf power index.
Using Technology to Support Expository Reading and Writing in Science Classes

Students struggle with the transition from learning to read narra- tive text in the early grades to reading expository text in the science classroom in the upper grades as they begin reading and writing to gain information. Science teachers can adapt their teaching materials to develop students' read- ing comprehension and recall by writing summaries of scientific text. Using technology, teachers can scaffold text comprehension and improve students' reading and writing skills. Technology encourages improved comprehension of reading and more elaborate writing in the science classroom by motivating students to act on their curiosity, access resources, and embellish their work.
An in situ XRF system for composition mapping of thin film IR sensors

Ge 1-x Sn x thin films are capable of detecting mid- to long IR wavelengths. However, due to the size difference between Ge and Sn atoms, homogeneous alloys are difficult to manufacture in thicknesses greater than a couple hundred nanometers. To address the difficulty in manufacturing these IR detecting alloys, we developed an in situ-capable x-ray fluorescence (XRF) system to characterize and monitor thin film composition and concentration information as a function of position during thin film growth. The inclusion of a focusing polycapillary optic enabled the x-ray source and detector distances from the sample to be large enough for placement outside the deposition chamber. RF sputtered, metastable Ge 1-x Sn x thin films (∼ 4 μm, ∼ 8 pm) were compositionally mapped with the XRF system. Since Sn phase separation destroys the IR capabilities of the Ge 1-x Sn x sensor, it is imperative to prevent this during deposition. Additionally, to produce an IR sensing array, more gradual changes in composition are desired. With our system, both Sn phase separation and more gradual changes in alloyed Sn concentrations were observed in 1000 s. However, the signal-to-noise ratio was such that 100 s would have been sufficient, meaning this system could be used in situ to characterize the alloy composition during deposition. A spatial resolution of ± 25 μm was obtained by oversampling with the focusing optic (100 μm spot size). From these measurements, the minimum detectable limits were on the order of nanograms using the Sn-L α signal, which corresponds to picograms from a Sn-K α signal. Such low levels are usually only possible with a rotating anode source 10 3 times more powerful than the low power sealed tube source used in this experiment. Additional ultra thin samples (< 100 nm) made by ion implantation were also analyzed with this XRF system. Sn was ion implanted into single crystal Ge, resulting in a sample representative of early stage thin film growth. In 300 s, a detectable signal was obtained, indicating the viability of this system for in situ, thin film, composition monitoring and characterization of uniformly alloyed metastable semiconductors for IR sensors.
VALUE VERSUS CHROMA IN COLOR SCHEMES ON QUANTITATIVE MAPS

Graphic portrayal of the dimensions of value (lightness) and chroma (intensity or saturation) of colours permits greater understanding of how these dimensions affect map readers' reactions to colours on quantitative maps. Specifically, when changes in value and chroma on test maps of a choropleth type are correlated with reader's reactions to these test maps it is found that chroma is extremely potent as a variable in a map reader's perception of varying magnitudes, and if not carefully controlled can render a colour scheme quite ineffective. La representation graphique de l'etendue de la valeur (clarte) et de la chromie (intensite ou saturation) des couleurs permet de mieux comprendre comment cette etendue influe sur les reactions aux couleurs de celui qui examine des cartes quantitatives. Surtout, lorsque des changements dans la valeur et la chromie sur des cartes d'essais de type choroplethes sont mis en correlation avec les reactions des lecteurs a ces cartes d'essai, on s'apercoit que la chromie est ...
Protein kinase A directly regulates the activity and proteolysis of cubitus interruptus

Cubitus interruptus (Ci) is a transcriptional factor that is positively regulated by the hedgehog (hh) signaling pathway. Recent work has shown that a 75-kDa proteolytic product of the full-length CI protein translocates to the nucleus and represses the transcription of CI target genes. In cells that receive the hh signal, the proteolysis of CI is inhibited and the full-length protein can activate the hh target genes. Because protein kinase A (PKA) inhibits the expression of the hh target genes in developing embryos and discs and the loss of PKA activity results in elevated levels of full-length CI protein, PKA might be involved directly in the regulation of CI proteolysis. Here we demonstrate that the PKA pathway antagonizes the hh pathway by phosphorylating CI. We show that the PKA-mediated phosphorylation of CI promotes its proteolysis from the full-length active form to the 75-kDa repressor form. The PKA catalytic subunit increases the proteolytic processing of CI and the PKA inhibitor, PKI, blocks the processing. In addition, cells do not process the CI protein to the 75-kDa repressor when all of the PKA sites in CI are mutated. Mutant CI proteins that cannot be phosphorylated by PKA have increased transcriptional activity compared with wild-type CI. In addition, exogenous PKA can increase further the transcriptional activity of the CI mutant, suggesting that PKA has a second positive, indirect effect on CI activity. In summary, we show that the modulation of the hh signaling pathway by PKA occurs directly at the level of CI phosphorylation.
Identification of reentry circuit sites during catheter mapping and radiofrequency ablation of ventricular tachycardia late after myocardial infarction.

BACKGROUNDVentricular tachycardia reentry circuits in chronic infarct scars can contain slow conduction zones, which are difficult to distinguish from bystander areas adjacent to the circuit during...
The Space Infrared Interferometric Telescope (SPIRIT) : Optical System Design Considerations

SPIRIT is a candidate NASA Origins Probe mission. It is a spatial and spectral interferometer operating at 4 K with an operating wavelength range 25 - 400 microns. This paper describes the various components of the candidate optical system, including telescopes, pointing and tracking optics, along with their functions. Some of the tradeoffs involved in selecting various components, with their particular characteristics, are described.
The Character of Psychological Theories

(1955). The Character of Psychological Theories. The Journal of General Psychology: Vol. 52, No. 2, pp. 197-203.
Digestible Lysine Requirement of Male and Female Broiler Chicks During the Period Three to Six Weeks Posthatching

Abstract Experiments were conducted to determine the dietary digestible lysine requirement of male and female broilers (Ross × Ross) during the period 22 to 43 d posthatching. An amino acid-fortified basal diet containing corn, feather meal, and soybean meal as intact protein sources provided .63% total lysine, 20% CP, and 3,200 kcal MEn/kg. The basal diet contained .51% true digestible lysine as determined with a precision-fed cecectomized adult cockerel assay. Growth rate and feed efficiency of birds fed the basal diet fortified with a surfeit level of L-lysine were equal to those of birds fed a methionine-supplemented corn-soybean meal positive control diet (20% CP; 3,200 kcal MEn/kg). Graded levels of synthetic L-lysine (0, .1, .2, .3, .4, .5, .6%) were added to the basal diet to produce growth response curves. Subjecting the growth data to broken-line analysis indicated that the digestible lysine requirement for maximum body weight gain was .85% for males and .78% for females. The requirement for optimum feed efficiency was higher: .89% for males and .85% for female broilers. Breast meat (Pectoralis major) yield increased quadratically in response to lysine addition, and the responses suggested that the lysine requirement for maximal breast yield was not greatly different from that predicted from the feed efficiency data. Abdominal fat (percentage of live body weight) increased from the first to the second increment of lysine, but it then declined as lysine level was increased further.
Index to Puerto Rican Collective Biography

Preface General Abbreviations and Symbols Keys to Abbreviations of Sources Indexed Index to Puerto Rican Collective Biography Bibliography of Sources Indexed Selective Bibliography of Related Materials Bibliographies Consulted
Effect of positive charge concentration on TG of completely amorphous salt–polyether solutions

Abstract Solutions of salts in amorphous polyethers and charged species derivatized with polyethers have been found to both adhere to a common plot of glass transition temperature, T G , against cationic charge per polyether oxygen. It is proposed that the T G increase is mainly due to the (ion–dipole) solvation of cations, which increases the barriers to segmental motions. The salt induced shrinkage of the polymer only partially contributes to the increase and coordinative crosslinking by the cations has been ruled out as a principal cause.
Joint probabilities of partially coupled events

This paper considers the joint and conditional probabilities of a number of (not necessarily identical) components which are all influenced to variable degrees by a single common extraneous factor. Explicit formulae are derived for these probabilities for specific values or statistical distributions of the common perturbing factor.
The National Home Study Council, 1926–1942

As enrollments in correspondence schools soared in the early twentieth century, unethical practices marred the reputation of this type of learning. Prominent schools created the National Home Study...
Picosecond and Terahertz Perturbation of Interfacial Water and Electropermeabilization of Biological Membranes

Non-thermal probing and stimulation with subnanosecond electric pulses and terahertz electromagnetic radiation may lead to new, minimally invasive diagnostic and therapeutic procedures and to methods for remote monitoring and analysis of biological systems, including plants, animals, and humans. To effectively engineer these still-emerging tools, we need an understanding of the biophysical mechanisms underlying the responses that have been reported to these novel stimuli. We show here that subnanosecond (≤500 ps) electric pulses induce action potentials in neurons and cause calcium transients in neuroblastoma-glioma hybrid cells, and we report complementary molecular dynamics simulations of phospholipid bilayers in electric fields in which membrane permeabilization occurs in less than 1 ns. Water dipoles in the interior of these model membranes respond in less than 1 ps to permeabilizing electric potentials by aligning in the direction of the field, and they re-orient at terahertz frequencies to field reversals. The mechanism for subnanosecond lipid electropore formation is similar to that observed on longer time scales-energy-minimizing intrusions of interfacial water into the membrane interior and subsequent reorganization of the bilayer into hydrophilic, conductive structures.
HYPEROXIA, NEUROTROPHINS, GLUTATHIONE AND APOPTOSIS DURING DEVELOPMENT.▴ 2263

Preterm infants are routinely treated with high concentrations of oxygen(hyperoxia) and fed using total parenteral nutrition lacking antioxidants (in particular cysteine a rate limiting precursor of glutathione), a combination which may contribute to the poor neurological outcome often observed in these neonates. We have hypothesized that such treatments may impact on the CNS via a sequence of events that includes reductions in glutathione (GSH) and nerve growth factor (NGF), followed by an induced increase in programmed cell death or apoptosis. In order to investigate these phenomena we measured GSH(spectrophotometrically), NGF (by ELISA) and apoptosis (by ELISA) in newborn rats treated with high concentrations (> 98%) of oxygen and with buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, in order to reproduce the above clinical situation. Four groups of newborn rats (beginning at 2 d of age) were studied: 1) Air (5 d) Control; 2) Air (5 d) + BSO (days 2-5); 3) Oxygen (> 98%) (5 d); and 4) Oxygen (5 d) + BSO (days 2-5). Oxygen alone results in decreases in GSH and NGF but only the combination of oxygen plus BSO results in statistically significant increases in apoptosis in the hippocampus (Air/BSO = 130 ± 32%; O2 alone = 147 ± 34; O2/BSO = 304 ± 85*, mean percent of control ± SD,* p < 0.001 vs Air alone). A similar pattern of response to these treatments was observed in the cerebellum. These data support the hypothesis that hyperoxic injury may be mediated by perturbations in neurotrophin and GSH homeostasis. Apparently the combination of hyperoxia and antioxidant deficiency places the brain in a particularly vulnerable state. Prevention of such injury in infants may be possible by administration of appropriate antioxidant precursors and/or by their inclusion in parenteral nutrition solutions.
Toward autonomous vehicle safety verification from mobile cyber-physical systems perspective

Safety certification of Autonomous Vehicles (AVs) require guarantees on AVs' safety at design time. To this effect, this paper proposes modeling abstractions that allow architectural representation of AVs and their surroundings, i.e. representation of different components, and enable safety analysis from such representation without requiring any expertise on formal methods. Toward this direction, AVs are considered as Cyber-Physical Systems with Mobile computing nodes (MCPS), where each node (i.e. an AV) can have intentional (as determined by AVs' controller) and unintentional (e.g., in case of skids) motion characteristics depending on the physical environment (e.g. road condition). The modeling abstractions are used to analyze safety of passengers in an AV that collides with guard rail due to skid along a curved segment on the AZ-83 highway.
An endophytic Gliocladium sp. of Eucryphia cordifolia producing selective volatile antimicrobial compounds

Abstract An endophytic isolate of Gliocladium sp. was obtained from the Patagonian Eucryphiacean tree— Eucryphia cordifolia , known locally as “ulmo”. The fungus was identified on the basis of its morphology and aspects of its molecular biology. This fungus produces a mixture of volatile organic compounds (VOC's) lethal to such plant pathogenic fungi as Pythium ultimum and Verticillum dahliae , while other pathogens were only inhibited by its volatiles. Some of the same volatile bioactive compounds exuded by Gliocladium sp. such as 1-butanol, 3-methyl-, phenylethyl alcohol and acetic acid, 2-phenylethyl ester, as well as various propanoic acid esters, are also produced by Muscodor albus , a well known volatile antimicrobial producer. In fact, M. albus was used as a selection tool to effectively isolate Gliocladium sp. since it is resistant to VOC's produced by M. albus . However, the primary volatile compound produced by Gliocladium sp. is 1,3,5,7-cyclooctatetraene or [8]annulene, which by itself, was an effective inhibitor of fungal growth. The authenticated VOC's of Gliocladium sp. were inhibitory to all, and lethal to some test fungi in a manner that nearly mimicked the gases of Gliocladium sp. itself. This report shows that the production of selective volatile antibiotics by endophytic fungi is not exclusively confined to the Muscodor spp.
Why the Multiphase Flow Community Should Be Interested in the Office of Science at the U.S. Department of Energy

This presentation is to introduce the Engineering Physics Program within the Office of Basic Energy Sciences in the Office of Science (SC) at the U.S. Department of Energy (DOE). The program portfolio covers fundamental scientific investigations in theory, simulation and experiment on multiphase fluid dynamics, granular materials, heat transfer and other areas. The unique characteristics of current and planned SC/DOE experimental and computational user facilities are described as well as opportunities within DOE experimental facilities for the development of capabilities to characterize multiphase flow. Opportunities and the process for obtaining future research support are discussed.Copyright © 2003 by ASME
A Collision of Principles? Free Expression, Racial Equality and the Prohibition of Racist Speech

Freedom of expression is celebrated as one of the glories of the American political system. But does all speech deserve immunity? In particular, should speech designed to vilify or degrade on the basis of race be protected? Opinions on racist speech are complicated because they must accommodate two fundamental democratic principles that operate at cross purposes: freedom of expression, which implies support for racist speech, and racial equality, which implies the opposite. Using data from the 1990 General Social Survey, we examine how Americans resolve this conflict. Our major finding is that the principle of free expression dominates the principle of racial equality. What contemporary legal scholars regard as a hard case entailing a collision of democratic principles, ordinary Americans seem to interpret as a straightforward application of just a single principle. This result mirrors and perhaps reflects a nearly century-long and mostly lop-sided debate favouring free speech among American elites.
Cross-Interaction between JC Virus Agnoprotein and Human Immunodeficiency Virus Type 1 (HIV-1) Tat Modulates Transcription of the HIV-1 Long Terminal Repeat in Glial Cells

The human polyomavirus JC virus (JCV) is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), which is commonly seen in AIDS patients. The bicistronic viral RNA, which is transcribed at the late phase of infection, is responsible for expressing the viral capsid proteins and a small regulatory protein, agnoprotein. Immunohistochemical analysis of brain tissue from subjects with AIDS/PML revealed colocalization of the human immunodeficiency virus type 1 (HIV-1) transactivator, Tat, and JCV agnoprotein in nucleus and cytoplasm of “bizarre” astrocytes. In accord with this observation, we detected the copresence of agnoprotein and Tat in human astrocytes upon infection with JCV and HIV-1 or in astrocytic cells expressing these proteins after transfection. Interestingly, results from infection of human astrocytes with HIV-1 and JCV showed a decrease in the level of HIV-1 replication in cells that are coinfected with JCV. Conversely, a slight increase in the level of JCV replication was observed in the presence of HIV-1. The copresence of JCV and HIV-1 in astrocytes prompted us to investigate the possible cross-interaction of agnoprotein with Tat and its impact on HIV-1 gene transcription. Our results demonstrate that agnoprotein through its N-terminal domain associates with Tat and the interaction causes the suppression of Tat-mediated enhancement of HIV-1 promoter activity in these cells. Results from RNA and protein binding assays showed that agnoprotein can inhibit the association of Tat with its target RNA sequence, TAR, and with cyclin T1. Furthermore, agnoprotein is able to interfere with cross-interaction of Tat with the p65 subunit of NF-κB and Sp1, whose functions are critical for Tat activation of the long terminal repeat. These observations unravel a new pathway for the molecular interaction of these two viruses in biologically relevant cells in the brains of AIDS/PML patients.
Behavior of discontinuous fiber composites: Fiber orientation

The behavior of polymeric materials reinforced by discontinuous. Descriptors for the planar and axial orientation distributions are discussed. Predictions of micromechanical models and experimental data are presented to illustrate the influence of orientation state upon elastic constants, thermal coefficients of expansion and tensile strength. Results are presented for the notched strength and compressive creep behavior of the glass/phenolic composite of two orientation states. Finally, the implications of these results upon the design of elements molded of discontinuous fiber composites are discussed.
Onset and Disappearance of Gastrointestinal Symptoms and Functional Gastrointestinal Disorders

Functional gastrointestinal disorders, including the irritable bowel syndrome, account for up to 40% of referrals to gastroenterologists, but accurate data on the natural history of these disorders in the general population are lacking. Using a reliable and valid questionnaire, the authors estimated the onset and disappearance of symptoms consistent with functional gastrointestinal disorders. An age- and sex-stratified random sample of 1,021 eligible residents of Olmsted County, Minnesota, aged 30-64 years were initially mailed the questionnaire; 82% responded (n = 835). In a remailing to responders 12-20 months later, 83% responded again (n = 690). The age- and sex-adjusted prevalence rates per 100 for irritable bowel syndrome, chronic constipation, chronic diarrhea, and frequent dyspepsia were 18.1 (95% confidence interval (CI) 15.1-21.1), 14.7 (95% CI 11.9-17.4), 7.3 (95% CI 5.3-9.3), and 14.1 (95% CI 11.5-16.8), respectively, on the second mailing. Symptoms were not significantly associated with nonresponse to the second mailing; moreover, the estimated prevalence rates were not significantly different from the first mailing. Among the 582 subjects free of the irritable bowel syndrome on the first survey, 9% developed symptoms during 795 person-years of follow-up, while 38% of the 108 who initially had the irritable bowel syndrome did not meet the criteria after 146 person-years of follow-up. Similar onset and disappearance rates were observed for the other main symptom categories. While functional gastrointestinal symptoms are common in middle-aged persons and overall prevalence appears relatively stable over 12-20 months, substantial turnover is implied by the observed onset and disappearance rates; several potential sources of bias do not seem to account for this variation.