cssi/SciSciGPT-SciSciNet huggingface dataset:
214 IN VITRO MIGRATION OF ADIPOSE-DERIVED STEM CELLS FROM GFP PIGS INTO POLYCAPROLACTONE SCAFFOLDS TREATED WITH FGF OR BMP2

We have previously demonstrated that adipose-derived stem cells (ASC) enhance healing of craniofacial bone in vivo. The use of scaffolds in large bone defects can further enhance the healing capacity of ASC. In addition, the presence of fully differentiated cells might affect ASC migration/proliferation into scaffolds. In this study, we have evaluated the in vitro capacity of ASC isolated from fat of GFP transgenic pigs to migrate into polycaprolactone (PCL) scaffolds conjugated with FGF or BMP2 with or without combinations of ASC with pig endothelial and/or neuronal cells. The ASC were extracted from the back fat of a GFP boar while the endothelial cells (ENDO) were extracted from the aorta a newborn piglet and the neurons (NEU) from the brain of a 37 days fetus. All cells were used at passage 3. In a 24-well plate, approximately 10 000 cells (only ASC, ENDO, or NEU, or equal combination of ASC+ENDO, ASC+NEU, or ASC+ENDO+NEU) were plated. The cells were grown for 3 days before adding the scaffolds in the wells. The scaffolds were treated with basic human FGF (25 ng mg–1 of scaffold), porcine BMP2 (400 ng mg–1 of scaffold), or no treatment (CTR). The scaffolds were then added to the plate and the medium was changed every 3 days. Using an Olympus IX71 microscope with automatic stage several pictures at 100× and 200× magnifications were taken and time-lapse visualisation of the movement of cells into the scaffold was performed during the first week. At 24 days the scaffolds were fixed with formalin. In order to estimate cell size and visualise non-GFP cells all scaffolds were treated with DAPI. Final photographs of the whole scaffold using a multiple alignment images features at 40× magnification were performed using GFP and DAPI filter plus brightfield. The figures were analysed with ImageJ to quantify the area of GFP and DAPI in the scaffolds. Percentage GFP and DAPI over scaffold area were calculated. Data were analysed using a Proc ANOVA of SAS, with cells and treatment as fixed effects and well as random. At 1 week from the beginning of the trial, we observed ASC cells on the scaffolds. The time-lapse showed ASC actively moving on the scaffold surface and entering into its micropores. The quantification of GFP and DAPI showed a significant larger percentage area covered by GFP cells in scaffolds treated with FGF (P < 0.05) compared to CTR or BMP2 (32 ± 4.6 vs 12.8 ± 9.1 and 3.8 ± 0.1). We observed a numerical lower area covered by GFP in scaffolds treated with BMP2 compared to CTR. The same trends were observed for the area covered by DAPI with a numerically lower colonization of the scaffolds by ENDO when treated with BMP2 vs CTR. Data showed that ASC, as well ENDO and NEU, are able to home into PCL scaffolds. The conjugation of the scaffolds with FGF has a positive effect on ASC migration, with no effects of BMP2. Data support the use of PCL scaffolds to enhance the bone healing capacity in vivo of ASC with a likely further improvement if scaffolds are treated with FGF before implantation.
RNA EDITING WORLD'S SMALLEST INTRONS ?

Thomas R. Cech Department of Chemistry and Biochemistry Howard Hughes Medical Institute University of Colorado Boulder, Colorado 80309-0215 It once seemed that the nucleotide sequence of every mRNA would be a simple copy of the sequence of its DNA template. This concept suffered its first jolt in 1977 with the discovery that intervening sequences or introns inter- rupted many eukaryotic genes. It is now well documented that these sequences are removed at the RNA level by cleavage-ligation reactions known as RNA splicing. A second major jolt occurred with the recent finding that in- dividual nucleotides within some mRNAs are posttran- scriptionally inserted, deleted, or altered in sequence- processes termed RNA editing. Certain mitochondrial pre-mRNAs in the parasitic pro- tozoa Trypanosoma, Leishmania, and Crithidia are exten- sively edited to give the mature, functional mRNA; U residues are added and deleted at multiple sites along the molecule (Benne et al., 1986; Feagin et al., 1987; Simp- son, 1990). Guide RNAs, short RNAs that are complemen- tary (if one allows UG wobble pairs) to edited portions of the mature mRNA, have been discovered and are thought to provide the information for this editing process (Blum et al., 1990). Sequence analysis of partially edited RNA molecules that are thought to represent intermediate steps in the process has indicated that editing involves successive cycles of U addition or deletion. It has been proposed that cycles proceed in an orderly 3’ to 5’ direc- tion (Feagin et al., 1988; Sturm and Simpson, 1990; Van der Spek et al., 1990). Alternatively, cycles might be unor- dered within precisely defined domains of editing (Decker and Sollner-Webb, 1990). This minireview does not address the progression of cy- cles of editing along the mRNA but rather the chemical steps within a single cycle of editing. Models proposed for these events invoke a number of enzymatic activities, in- cluding an endonuclease, a terminal uridylyl transferase (TUTase), an RNA ligase, and, for the U-deletion reaction, a 3’ exonuclease (Feagin et al., 1988; Blum et al., 1990; Van der Spek et al., 1990; Simpson, 1990). The most ex- plicit of these models is shown in Figure 1. I propose an alternative model, in which the removal of U’s is accomplished by a transesterification mechanism analogous to that of RNA splicing (Cech, 1986a), and the addition of U’s is accomplished by a reaction analogous to reverse splicing (Woodson and Cech, 1989). Thus, a single active site could perform all of RNA editing. The addition of one or more U residues to the middle of an RNA could occur as shown in Figure 2a. The 3’end of an oligo(U) sequence attacks the pm-mRNA at a posi- tion where it is mismatched with the guide sequence. In a concerted cleavage-ligation reaction, the pre-mRNA is cleaved and U’s become added to the 5’ end of a 3’-ter-
Exact solution of a simple exciton model in one-dimension

Abstract The model consists of two parabolic bands of opposite mass separated by a gap. The spinless holes in the valence band and the spinless electrons in the conduction band are locally attracted. The exact solution of the model is sketched and some low temperature properties are discussed.
Metabolism of D-galactose to D-glucuronic acid, L-gulonic acid and L-ascorbic acid in normal and barbital-treated rats.

Abstract 1. 1. In vivo experiments in rats showed that D -[1- 14 C]galactose was better than D -[1- 14 C]glucose as a precursor of D -glucuronic acid, L -gulonic acid and L -ascorbic acid. The conversion of D -[1- 14 C]galactose to D -glucuronic acid and L -gulonic acid was demonstrated in rat-liver homogenate. The results presented are in accord with the biosynthesis of L -ascorbic acid via the uridine nucleotides. 2. 2. The administration of barbital to rats stimulated the in vivo conversion of D -[1- 14 C]galactose to D -glucuronic acid, L -gulonic acid and L -ascorbic acid. Enhanced formation of D -glucuronic acid from D -[1- 14 C]galactose was also observed in liver homogenates from rats pretreated with Chloretone. 3. 3. Formation of D -galacturonic acid from D -galactose in vivo was not detected in rats.
PKC activation by resveratrol derivatives with unsaturated aliphatic chain.

Resveratrol (1) is a naturally occurring phytoalexin that affects a variety of human disease models, including cardio- and neuroprotection, immune regulation, and cancer chemoprevention. One of the possible mechanisms by which resveratrol affects these disease states is by affecting the cellular signaling network involving protein kinase C (PKC). PKC is the family of serine/threonine kinases, whose activity is inhibited by resveratrol. To develop PKC isotype selective molecules on the resveratrol scaffold, several analogs (2–5) of resveratrol with a long aliphatic chain varying with number of unsaturated doubled bonds have been synthesized, their cytotoxic effects on CHO-K1 cells are measured and their effects on the membrane translocation properties of PKCα and PKCe have been determined. The analogs showed less cytotoxic effects on CHO-K1 cells. Analog 4 with three unsaturated double bonds in its aliphatic chain activated PKCα, but not PKCe. Analog 4 also activated ERK1/2, the downstream proteins in the PKC signaling pathway. Resveratrol analogs 2–5, however, did not show any inhibition of the phorbol ester-induced membrane translocation for either PKCα or PKCe. Molecular docking of 4 into the activator binding site of PKCα revealed that the resveratrol moiety formed hydrogen bonds with the activator binding residues and the aliphatic chain capped the activator binding loops making its surface hydrophobic to facilitate its interaction with the plasma membrane. The present study shows that subtle changes in the resveratrol structure can have profound impact on the translocation properties of PKCs. Therefore, resveratrol scaffold can be used to develop PKC selective modulators for regulating associated disease states.
ACCELERATION OF LIMITED FREEZE-DRYING IN CONVENTIONAL DRYERS

Limited freeze-drying leaves a substantial, predetermined and uniform moisture content, such as is required for compression of the product. The process can be accomplished by modification of ordinary freeze-dryers. It is shown that the time required for limited freeze-drying can be reduced by as much as a factor of two through the use of programmed platen temperatures, starting with higher temperatures which are then reduced as drying proceeds. 1-cm cubes of cooked beef can be dried to a uniform average moisture, content of 10% in 7 hr in this way. The observed temperature histories and drying times agree well with the predictions of a quantitative model for asymmetric freeze-drying.
Media Ethics in a Fast Changing Media Environment

Drushel, B. E., & German, K. (Eds.). (2011). The ethics of emerging media: Information, social norms, and new media technology. New York, NY: Continuum Books. 279 pp., $34.95 (Pbk). Developing a co...
Interrater reliability and content validity of a minimal data set to measure outcomes of students receiving school-based occupational therapy and physical therapy.

Background and Purpose: The 1997 Amendments of the Individuals with Disabilities Education Act increased the emphasis on accountability for outcomes of students with disabilities in the United States. The purpose of this study was to determine the content validity and estimate the interrater reliability of the School Outcomes Measure, a new minimal data set to measure groups of students' performance in the areas addressed by school-based therapy. Method: Forty-five occupational therapists and physical therapists working in Oklahoma's public schools participated in the content validity study. Eight occupational therapist-physical therapist pairs rated 17 students for the interrater reliability study. Therapists were recruited and data were collected by mail for both studies. Results: Most validity study participants thought the tool was comprehensive and clear, and that they could complete the tool twice a year for their students. The weighted kappa statistic indicated that the therapists' agreement was su...
On the synthesis of a large geomagnetic array from small overlapping arrays

Summary We describe a general method for combining multiple station transfer function results (i.e., uniform source response space estimates) from a large number of overlapping small geomagnetic arrays, to produce an estimate of the uniform source response for a large synthetic array. The resulting synthesized response can be used to plot anomalous magnetic fields in a region covered by the non-simultaneous arrays. We show that this general array synthesis problem can be approximately reduced to a fairly simple non-linear least-squares problem. Because the number of parameters is very large, we develop a specialized and efficient estimation scheme which exploits the special structure of the problem. We also discuss the computation of a large sample approximation to the covariance matrix of the earth response parameters. While the method has been developed for combining non-simultaneous arrays, it can also be used to ‘patch up’ large simultaneous arrays with some missing data. Both aspects of the method are illustrated on an overlapping set of 19 three-five-station three-component magnetovariational arrays from southwestern Washington. Results from the synthetic 49 station three-component array are discussed briefly.
Body composition and energetic efficiency in two lines of mice selected for rapid growth rate and their F1 crosses.

Correlated responses to selection for increased growth rate were compared in two mouse populations (M16 and H6) of distinct genetic origin. Traits studied were body composition, feed intake, constituent gains and energetic efficiency. When compared with their respective controls (ICR and C2) at 6 and 9 weeks of age, body weight increased more in M16 (57%and 69 % of the control mean) than in H6 (40 % and 34%). The M16 showed correlated responses in fat percent of 2.6% (P .05). The correlated responses in fat percent were 2.7 and 4.7 times higher in M16 than H6 at 6 and 9 weeks. The regression of ln fat weight on ln empty body weight was larger in M16 (P <.05) compared to ICR and larger (P <.01) in H6 compared to C2. Both M16 and H8 exhibited positive correlated responses from 3 to 6 weeks of age in feed intake and gain and efficiency in fat, protein, calories and ash; fat and caloric gain and efficiency exhibited higher correlated responses in M16 than H6. During the 6- to 9-week interval, the M16 population continued to evince positive correlated responses in gains and efficiencies of fat, protein and calories, whereas H6 did not. Several possible explanations are presented to account for the differences in correlated responses between the selected populations. Partitioning of correlated response differences between M16 and H6 into average direct and average maternal genetic effects indicated that average direct genetic effects, favoring M16, were responsible for the major difference between the selected populations. Direct heterosis in F1 crosses of the selected populations were generally not significant, although there was a tendency for fat percent and fat weight to show heterosis.
Unresolved pulmonary embolism: The value of surgical management with extensive thrombo-endartectomy

In a small but definite number of patients with pulmonary embolism, either gradual resolution of the embolus does not occur or recurrent showers of emboli follow the acute onset, leading to a state of chronic pulmonary hypertension. Two new cases treated surgically without the use of cardiopulmonary bypass are described. The results were excellent in both cases with relief of the dyspnoea and an improvement in the Po 2 , a result that has been documented in the follow-up of 2–6 years. The only definite treatment of this chronic obstructive pulmonary hypertension is pulmonary thrombo-endarterectomy.
Immunoreactivity of CD99 in invasive malignant melanoma.

Background: CD99, also known as p30/32, is a glycoprotein product of the MIC2 gene. It was originally utilized in immunohistochemistry as a unique marker for Ewing sarcoma, other primitive neuroectodermal tumors, and subsequently in other tumors. Its expression in malignant melanoma (MM) has not been well documented, with just two isolated cases of MM recently reported. Recent studies have documented CD99 expression in a significant percentage of atypical fibroxanthomas (AFX), posing potential diagnostic problems in differentiating these two entities. As mistaking MM for AFX based on immunohistochemical staining pattern has significant consequences, we sought to determine the percentage of invasive MM in our archives that have this staining pattern. Methods: Seventy-eight cases of invasive melanoma were retrieved from our files. Each case was stained with mouse anti-human CD99 and evaluated for membranous expression. Results: Our evaluation revealed that 47 of 78 MM cases (60%) stain positive for CD99. Conclusion: This study is the first to demonstrate, in a large series, the prevalence of CD99 expression in primary cutaneous melanoma. Additionally, this introduces in the histologic differential diagnosis of CD99 expressing dermal spindle cell lesions.
Generation of Z mode radiation by diffuse auroral electron precipitation

The generation of Z mode waves by diffuse auroral electron precipitation is investigated assuming that a loss cone exists in the upgoing portion of the distribution due to electron interactions with the atmosphere. The waves are generated at frequencies above, but very near, the local electron cyclotron frequency omega(e) and at wave normal angles larger than 90 deg. In agreement with Hewitt et al. (1983), the group velocity is directed downward in regions where the ratio of the upper hybrid frequency omega(pe) to Omega(e) is less than 0.5, so that Z mode waves excited above a satellite propagate toward it and away from the upper hybrid resonance. Z mode waves are excited in a frequency band between Omega(e) and about 1.02 Omega(e), and with maximum growth rates of about 0.001 Omega(e). The amplification length is about 100 km, which allows Z mode waves to grow to the intensities observed by high-altitude satellites.
Fas-mediated T cell deletion potentiates tumor antigen-specific tolerance in a mouse model of prostate cancer

A pivotal obstacle to cancer immunotherapy is peripheral T cell tolerance to tumor-associated antigens (TAAs). Tolerance induction among mature T cells in the periphery operates through a variety of mechanisms, including anergy and apoptosis. Although Fas-FasL-mediated apoptosis is a well-defined tolerance inducing mechanism, direct evidence of its interference with TAA-specific immunity in vivo is still lacking. In this report, we used the TRAMP mouse, which expresses SV40 large T antigen (Tag) preferentially in the prostate and develops prostate tumors, as a model system to address the role of Fas-mediated apoptosis in regulating peripheral T cell tolerance. Using RT-PCR and tetramer staining to quantify TAA-specific TCR-expressing cytolytic T lymphocytes (CTLs), we have shown the presence of TAA-specific CTLs at higher levels in TRAMP mice than in syngeneic C57Bl/6 mice. Tag-specific immunization led to the expansion of Tag-specific CTLs in C57Bl/6 mice, and to their elimination in TRAMP mice. Interestingly, in TRAMP mice with deficient Fas (Hybrid TRAMP-lpr/lpr), Tag-specific CTL elimination in response to Tag immunization did not take place. The results of cytolytic-function assays were consistent with induction and elimination patterns of TAA-specific CTLs and those of RT-PCR and tetramer staining. In conclusion, our data show that Fas-mediated TAA-specific CTL apoptosis contributes to T cell tolerance and suggest that such tolerance could be potentiated following TAA-specific immunization.
SRS: A framework for developing malleable and migratable parallel applications for distributed systems

The ability to produce malleable parallel applications that can be stopped and reconfigured during the execution can offer attractive benefits for both the system and the applications. The reconfiguration can be in terms of varying the parallelism for the applications, changing the data distributions during the executions or dynamically changing the software components involved in the application execution. In distributed and Grid computing systems, migration and reconfiguration of such malleable applications across distributed heterogeneous sites which do not share common file systems provides flexibility for scheduling and resource management in such distributed environments. The present reconfiguration systems do not support migration of parallel applications to distributed locations. In this paper, we discuss a framework for developing malleable and migratable MPI message-passing parallel applications for distributed systems. The framework includes a user-level checkpointing library called SRS and a runtime support system that manages the checkpointed data for distribution to distributed locations. Our experiments and results indicate that the parallel applications, with instrumentation to SRS library, were able to achieve reconfigurability incurring about 15-35% overhead.
Vesicular Ionic Aggregates in Poly(styrene-ran-methacrylic acid) Ionomers Neutralized with Cs

The morphologies of Cs-neutralized poly(styrene-ran-methacrylic acid) (Cs−SMAA) random ionomers have been studied using scanning transmission electron microscopy (STEM). The Cs−SMAA ionomers exhibit Cs-rich aggregates in the shape of spherical shells that are randomly distributed in a polystyrene-rich matrix. For simplicity, we refer to these as vesicular aggregates. The vesicular aggregates are typically 5−20 nm in diameter and have shell thicknesses of ∼3 nm. The vesicular aggregates persist after annealing with their dimensions and number density unchanged. The aggregate diameters and shell thicknesses are independent of the copolymer concentration during neutralization and the rate of neutralizing agent addition. We also demonstrate that our specimen preparation for STEM (microtomy parameters and storage conditions) avoids substantial changes to the bulk ionomer morphology. Overall, the microstructures of the current materials are similar to those recently reported in sulfonated polystyrene ionomers s...
Description of the torcetrapib series of cholesteryl ester transfer protein inhibitors, including mechanism of action

We have identified a series of potent cholesteryl ester transfer protein (CETP) inhibitors, one member of which, torcetrapib, is undergoing phase 3 clinical trials. In this report, we demonstrate that these inhibitors bind specifically to CETP with 1:1 stoichiometry and block both neutral lipid and phospholipid (PL) transfer activities. CETP preincubated with inhibitor subsequently bound both cholesteryl ester and PL normally; however, binding of triglyceride (TG) appeared partially reduced. Inhibition by torcetrapib could be reversed by titration with both native and synthetic lipid substrates, especially TG-rich substrates, and occurred to an equal extent after long or short preincubations. The reversal of TG transfer inhibition using substrates containing TG as the only neutral lipid was noncompetitive, suggesting that the effect on TG binding was indirect. Analysis of the CETP distribution in plasma demonstrated increased binding to HDL in the presence of inhibitor. Furthermore, the degree to which plasma CETP shifted from a free to an HDL-bound state was tightly correlated to the percentage inhibition of CE transfer activity. The finding by surface plasmon resonance that torcetrapib increases the affinity of CETP for HDL by ∼5-fold likely represents a shift to a binding state that is nonpermissive for lipid transfer. In summary, these data are consistent with a mechanism whereby this series of inhibitors block all of the major lipid transfer functions of plasma CETP by inducing a nonproductive complex between the transfer protein and HDL.
Substituted tetrahydro-β-carbolines as potential agents for the treatment of human papillomavirus infection

Abstract The identification and optimization of a series of substituted tetrahydro-β-carbolines with potent activity against human papillomavirus is described. Structure–activity studies focused on the substitution pattern and chirality of the β-carboline ring system are discussed. Optimization of these parameters led to compounds with antiviral activities in the low nanomolar range.
Transcarotid balloon valvuloplasty with continuous transesophageal echocardiographic guidance for neonatal critical aortic valve stenosis: an alternative to surgical palliation.

Neonatal critical aortic valve stenosis is a life-threatening malformation if untreated. Before the late 1980s, the preferred treatment was surgical valvotomy; however, operative mortality was high. Early reports of transcatheter balloon dilation were encouraging, although femoral artery damage and aortic valve insufficiency were procedural limitations. With new balloon catheter technology, transumbilical, transvenous, and transcarotid approaches have been advocated, although a comparison with recent surgical results has not been performed. We compared all neonates who presented to our institution since 1985 with the diagnosis of critical aortic stenosis. Ten patients underwent surgical transventricular valvotomy and 13 patients underwent balloon valvuloplasty via a right carotid cutdown with continuous transesophageal echocardiographic guidance. Prior to intervention, all patients had either left ventricular dysfunction, an aortic valve gradient >100 mmHg, significant mitral valve insufficiency, and/or ductal dependent systemic blood flow. All patients had successful relief of aortic valve obstruction with normalization of left ventricular function and successful discontinuation of prostaglandin E1. Use of continuous transesophageal echocardiographic guidance resulted in fluoroscopic exposure of only 12 ± 8 minutes. At the latest follow-up, a similar proportion of patients has required additional aortic valve procedures (38% vs 25%) and overall mortality (20% vs 15%) is similar. In the transcarotid group, 9 of 13 patients (69%) have a normal appearing right carotid artery by Duplex imaging, and no neurologic events have been reported. Balloon aortic valvuloplasty via a right transcarotid approach is safe, simplifies crossing the valve, and is effective for the initial palliation of neonatal critical aortic stenosis. The use of transesophageal echocardiographic guidance reduces fluoroscopy exposure, enables accurate assessment of hemodynamics without catheter manipulation or angiography, and avoids femoral artery injury.
Modeling Effects on Children's Form Kinematics, Performance Outcome, and Cognitive Recognition of a Sport Skill: An Integrated Perspective

Abstract This study examined the effectiveness of visual and verbal models during the initial phase of complex sport skill acquisition in children. Thirty-six girls between the ages of 7–0 and 8–11 years were randomly assigned to one of three experimental conditions in a 3 × 4 (Model Type × Trial Block) factorial design. A visual model performing an underhand modified softball pitch was viewed prior to each of four blocks of five practice trials. Verbal performance cues were added to the model at the second, third, or fourth trial block, according to the experimental condition. A multivariate repeated measures analysis of variance revealed a significant trial block main effect, with subjects showing improved matching of form kinematics to the model with increasing trials but no differences in performance outcome. More dramatic changes coincident with the addition of verbal cues were observed for some kinematic variables. Children exhibited better cognitive recognition of correct form as a function of incr...
Screening, diagnosis & monitoring of depression/distress in CHF patients.

Objective and validated measures of depression/distress (anxiety and anger) are available and readily usable at the bedside or in clinic. Foremost among these is the Patient’s Health Questionnaire—an adaptation of DSM IV criteria for Major Depressive Disorder that permits administration and scoring by nursing or physician personnel, and quantification of the intensity of depression. A score of 10 or greater indicates a need for evaluation/treatment. Because of patient denial/minimization/alexithymia, PHQ negatives should undergo further screening by having a spouse or friend complete a depression/distress rating scale. The only standardized, normed, and validated spouse/friend scale presently available is the Ketterer Stress Symptom Frequency Checklist, which is available by internet.
Some mechanisms of action of additives in electrodeposition processes

Abstract A review is given of mechanisms by which additives have been postulated to affect the rate of deposition of metals. These mechanisms include (1) blocking the surface, (2) changes in Helmholtz potential, (3) complex formation including induced adsorption and ion bridging, (4) ion pairing, (5) changes in interfacial tension and filming of the electrode, (6) hydrogen evolution effects, (7) hydrogen absorption, (8) anomalous codeposition and (9) the effect on intermediates.
An Achromatized Miniature Objective for Microendoscopy

An achromatized miniature objective with 0.6 NA, 488 µm FOV and 2.1 magnification, built with all spherical surfaces is presented. The lens is nearly diffraction-limited over a 486 - 1000 nm spectral range for in-vivo imaging.
On the meteorological characteristics of polluted air masses at Barrow, Alaska

Anthropogenic derived pollution episodes at Barrow, Alaska occur when air masses under anticyclonic influence emanate from the Arctic Basin. The high frequency of above-normal wind speeds and the only slightly above-normal pressures characteristic of these Arctic air masses suggest that pollutants are transported to Barrow along the periphery of the Arctic anticyclone within a zone of rapid transport.
Mechanical behavior of a bulk nanocrystalline Ni–Fe alloy

Abstract The mechanical behavior of a bulk nanocrystalline (nc) Ni–Fe alloy was studied in this paper. The microstructure of the as-deposited nc Ni–Fe alloy was characterized. The compressive and the fatigue properties of the bulk nc Ni–Fe alloy was investigated. The results indicate that bulk nc Ni–Fe alloy shows an extraordinary high strength, good ductility and a low fatigue-endurance limit.
Interaction analysis of dual-interaction CSCL environments

In order to collaborate effectively in group discourse on a topic like mathematical patterns, group participants must organize their activities so that they have a shared understanding of the significance of their utterances, inscriptions and behaviors--adequate for sustaining productive interaction. The need for participants to coordinate their actions becomes particularly salient in dual-interaction environments, where, e.g., chat postings and graphical drawings must work together; analysts of such interactions must identify the subtle and complex ways in which meaning making proceeds. This paper considers the methodological requirements on analyzing interaction in dual-interaction environments by reviewing several exemplary CSCL studies. It reflects on the nature of social organization, grounding and indexicality that frame the interaction to be analyzed.
Stable expression of full length human androgen receptor in PC‐3 prostate cancer cells enhances sensitivity to retinoic acid but not to 1α,25‐dihydroxyvitamin D3

BACKGROUND PC-3 prostate cancer cell growth is inhibited by 1α,25-dihydroxyvitamin D3 (1,25 D) and retinoids, but not to the same extent as the androgen receptor (AR) positive LNCaP prostate cancer cells. Previous reports suggest a role for AR in growth inhibition of LNCaP cells by 1,25 D and retinoids. PC-3 cells do not express AR. We therefore asked whether re-expression of AR would enhance the response of PC-3 cells to 1,25 D and retinoids. METHODS PC-3 cells were stably transfected with wild type human AR cDNA. Pooled cells expressing AR protein at levels comparable to LNCaP cells were used to analyze response to 1,25 D, retinoids, androgens, and anti-androgens. RESULTS AR re-expression in PC-3 cells restored response to androgens and anti-androgens, but growth inhibition by 1,25 D was not significantly altered. However, cells were sensitized to low levels of retinoids, and, in contrast to the parental PC-3 cells, sub-optimal levels of 1,25 D and retinoids caused additive growth inhibition. CONCLUSIONS Restoring AR expression and activity in PC-3 cells results in enhanced sensitivity to low levels of retinoids while the response to 1,25 D remains unaltered. Thus, the involvement of AR in prostate cancer growth inhibition by 1,25 D appears to be cell line specific. Prostate 56: 293–304, 2003. © 2003 Wiley-Liss, Inc.
Integrating implicit structure visualization with authoring promotes ideation

We need to harness the growing wealth of information in digital libraries to support intellectual work involving creative and exploratory processes. Prior research on hypertext authoring shifted the focus from explicit structure to direct presentation of content aided by "implicit" spatial representation of structure. We likewise shift the field of information visualization. Using hypertext's rubric, we redefine what most people think of as "information visualization" as explicit structure visualization. We alternatively address implicit structure visualization, presenting content directly, representing structure with spatiality and other visual features. We integrate authoring to emphasize the role of human thought in learning and ideation. Prior research has shown that people iteratively collect and organize information by clipping magazines, piling clippings in somewhat messy ways, and organizing them. MessyOrganizer is an iterative implicit structure visualization algorithm which, like human practice, gradually collects and organizes information clippings. Content is depicted directly. Structural relationships are visualized implicitly through spatial positioning of related elements, with overlap and translucence. The simulated annealing algorithm is applied to a model of semantic relatedness over a spatial grid. We develop an experiment comparing products created with the integrated environment versus separated visualization and authoring spaces. Results reveal that participants have more novel and varied ideas when visualization is integrated with authoring.
Kinetics of intermolecular cleavage by hammerhead ribozymes

The hammerhead catalytic RNA effects cleavage of the phosphodiester backbone of RNA through a transesterification mechanism that generates products with 2'-3'-cyclic phosphate and 5'-hydroxyl termini. A minimal kinetic mechanism for the intermolecular hammerhead cleavage reaction includes substrate binding, cleavage, and product release. Elemental rate constants for these steps were measured with six hammerhead sequences. Changes in substrate length and sequence had little effect on the rate of the cleavage step, but dramatic differences were observed in the substrate dissociation and product release steps that require helix-coil transitions. Rates of substrate binding and product dissociation correlated well with predictions based on the behavior of simple RNA duplexes, but substrate dissociation rates were significantly faster than expected. Ribozyme and substrate alterations that eliminated catalytic activity increased the stability of the hammerhead complex. These results suggest that substrate destabilization may play a role in hammerhead catalysis.
Chalcedonic quartz and occurrence of quartzine (length‐slow chalcedony) in pelagic sediments

ABSTRACT Chalcedony is the most abundant form of quartz in silicified pelagic sediments from the North Pacific. Varieties of chalcedonic quartz present in chert of deep-sea origin include chalcedony (length-fast and zebraic), quartzine (length-slow), and lutecite. These occurrences of quartzine in known pelagic sediments emphasize the dangers of using quartzine as an indicator of former evaporitic environments. Quartzine is a diagenetic mineral and does indicate pore fluids rich in sulphate and magnesium. In pelagic sediments, it is always associated with authigenic barite and in many cases with authigenic dolomite. Quartzine should not be used, by itself, as an indicator of any particular environment of deposition.
Duration of treatment in bacterial meningitis: a historical inquiry.

As soon as a new but still unproved method of treatment is adopted by even a minority of the medical profession, it becomes virtually impossible to conduct the controlled trial that alone can furnish truly reliable evaluation of its effectiveness and its hazards.
Measurement error, education production and data envelopment analysis

Abstract Data Envelopment Analysis has become a popular tool for evaluating the efficiency of decision making units. The nonparametric approach has been widely applied to educational production. The approach is, however, deterministic and leads to biased estimates of performance in the presence of measurement error. Numerous simulation studies confirm the effect that measurement error has on cross-sectional deterministic models of efficiency. It is also known that panel data models have the ability to smooth out measurement error, leading to more reliable efficiency estimates. In this paper, we exploit known properties of educational production to show that aggregation can also have a smoothing effect on production with measurement error, suggesting that efficiency analyses are more reliable than previously believed.
Nanophotonics: materials and devices

Optical technology plays an increasingly important role in numerous applications areas, including communications, information processing, and data storage. However, as optical technology develops, it is evident that there is a growing need to develop reliable photonic integration technologies. This will include the development of passive as well as active optical components that can be integrated into functional optical circuits and systems, including filters, switching fabrics that can be controlled either electrically or optically, optical sources, detectors, amplifiers, etc. We explore the unique capabilities and advantages of nanotechnology in developing next generation integrated photonic chips. Our long-range goal is to develop a range of photonic nanostructures including artificially birefringent and resonant devices, photonic crystals, and photonic crystals with defects to tailor spectral filters, and nanostructures for spatial field localization to enhance optical nonlinearities, to facilitate on-chip system integration through compatible materials and fabrication processes. The design of artificial nanostructured materials, PCs and integrated photonic systems is one of the most challenging tasks as it not only involves the accurate solution of electromagnetic optics equations, but also the need to incorporate the material and quantum physics equations. Near-field interactions in artificial nanostructured materials provide a variety of functionalities useful for optical systems integration. Furthermore, near-field optical devices facilitate miniaturization, and simultaneously enhance multifunctionality, greatly increasing the functional complexity per unit volume of the photonic system. Finally and most importantly, nanophotonics may enable easier integration with other nanotechnologies: electronics, magnetics, mechanics, chemistry, and biology.
Distributed database security

As critical information systems are increasingly moved from mainframe and proprietary platforms to open systems environments, the management and implementation of security faces complex challenges. This article describes several of the security challenges raised by heterogeneous, distributed database environments; for example, distributed authentication services, encryption of network data and secure remote database administration. It then proposes how some of these challenges can be addressed by using current and forthcoming releases of Oracle server and networking products. It also briefly discusses the increased complexity of those challenges in a multilevel secure environment. This article focuses primarily on aspects of security which concern confidentiality (or privacy) of information rather than those which concern integrity (or correct maintenance of information) and availability (or proper accessibility to information and continuity of that service). However, measures which protect confidentiality, such as password control, often also help to protect against threats to integrity and availability.
Steroidogenic Factor-1 Influences Protein-Deoxyribonucleic Acid Interactions within the Cyclic Adenosine 3′,5′-Monophosphate-Responsive Regions of the Murine Steroidogenic Acute Regulatory Protein Gene

De novo synthesis of the steroidogenic acute regulatory protein (StAR) in response to trophic hormonal stimulation of steroidogenic cells is required for the delivery of cholesterol from the mitochondrial outer membrane to the mitochondrial inner membrane and the cytochrome P450 side-chain cleavage enzyme. StAR expression is transcriptionally regulated by cAMP-mediated mechanisms, and we have identified a 45-bp region within the mouse promoter that is important for cAMP responsiveness of the gene. This region, located between −105 and −60 of the start site of transcription, contains a SF-1-binding site, a highly conserved C/EBPβ− AP-1-nuclear receptor half-site sequences (CAN region), and a GATA-4-binding site. The SF-1 element and CAN region are required for full basal activity, whereas the GATA-4 element may account for 20% of the cAMP response in MA-10 mouse Leydig tumor cells. A cAMP-dependent protein-DNA complex was observed with the CAN region and mutation of a nonconsensus AP-1 site within this reg...
Hollow glass microspheres for use in radiation shielding

Abstract The production of hollow glass microspheres from Li2O–Al2O3–B2O3 glasses was investigated. The production of hollow, rather than solid, spheres is enabled by the use of blowing agents in the glass, such as sulfate compounds. Irregular glass frit (25–100 μm in diameter) was fed into a propane/oxygen torch and spherodized. Solid spheres were easily obtained for all particle sizes and glass compositions studied, but the yield of spheres with single hollow cavities was very low. Raman scattering spectroscopy was performed on glass frit to determine glass structure and the presence of sulfur-containing groups. Glasses were batched to contain SO3, but Raman spectra show the presence of bands due to SO 4 2 - . The Raman spectra presented do not show a clear relationship between glass composition (structure) and the yield of solid or hollow spheres. The solubility of sulfate in lithium aluminoborate glasses is around 1 wt%, based on the appearance of white Li2SO4 inclusions in glasses made to contain 1 wt% SO3 or greater. Sulfate solubility in glass samples was also seen to decrease with increasing Al2O3 content.
Parallel magnetic resonance imaging using compressed sensing

Although magnetic resonance imaging (MRI) is routinely used in clinical practice, long acquisition times limit its practical utility in many applications. To increase the data acquisition speed of MRI, parallel MRI (pMRI) techniques have recently been proposed. These techniques utilize multi-channel receiver arrays and are based on simultaneous acquisition of data from multiple receiver coils. Recently, a novel framework called Compressed Sensing (CS) was introduced. Since this new framework illustrates how signals can be reconstructed from much fewer samples than suggested by the Nyquist theory, it has the potential to significantly accelerate data acquisition in MRI. This paper illustrates that CS and pMRI techniques can be combined and such joint processing yields results that are superior to those obtained from independent utilization of each technique.
Development of an Automated Parametric Geometry Environment for a Reusable Booster

RBS vehicle concepts must fly a challenging trajectory that includes high angles of attack and speeds ranging from high supersonic to low subsonic. Achieving trimmed flight throughout the envelope has proven to be a challenge for this type of vehicle and must be considered in early phases of design. This effort is supporting a study that is exploring the vehicle configuration tradespace parametrically in order to find the feasible, trim-able design space. A robust, automated geometry tool was developed in Pacelab Suite, a leading platform for knowledge based engineering, to support this research effort. This platform was chosen because its functional and object oriented infrastructure was needed due to deficiencies with the current off-the-shelf conceptual geometry tools at the time that this study began. Specific characteristics that were needed include parametric CFD-ready control surfaces, wing-body blending capabilities, and potential to have built-in support for internal packaging studies. This paper explains the RBS geometry environment focusing on the parameterization, including the development of parametric control surfaces and blends.
Preparing for Citizenship: Immigrant High School Students' Curriculum and Socialization

Immigrant adolescents are one of the fastest growing segments of our population, yet we know little about how schools prepare them for citizenship. Although prior research suggests that high school civics education, academic achievement, and a sense of connection increase political participation in early adulthood, we do not know if these processes apply to immigrant youth. Using longitudinal, nationally representative data from the Adolescent Health and Academic Achievement study (AHAA) and the National Longitudinal Study of Adolescent Health (Add Health), we employ multilevel models to investigate the effects of formal and informal school curricula on early adult voting and registration. We find that children of immigrant parents who take more high school social studies coursework have higher levels of reported voter registration and voting. In addition, attending a high school where students have a greater sense of connection or where parents have more education are important predictors of registration and voting, regardless of immigrant status.
The identification of neurotensin NTS1 receptor partial agonists through a ligand-based virtual screening approach.

We identified small molecule NTS1R agonist compounds through virtual screening of the corporate database using a ROCS approach that searches multi-conformer representations efficiently. As a starting point for the ROCS search, we used the known NTS1R selective antagonist, SR-48527, based on the hypothesis that NT agonists and antagonists might share similar binding regions. Conformations were expanded and selected as database search queries based on a cluster analysis. The search provided us with virtual hits that were tested in intracellular calcium mobilization assays of NTS1R agonist and antagonist activities measured in FLIPR format as well as in [ 3 H]NT competition binding studies. The results indicated that two initial hits produced partial agonist activity with potency in the moderate micromolar range.
Ecology: Wilson in Africa

Stuart Pimm enjoys a fellow naturalist's first visit to sub-Saharan Africa, and the global lessons drawn from it.
Enhancement of subtle geochemical anomalies by selective chemical extractions of metal from pebble coatings

Abstract Samples of stream water, fine-grained sediment and coated pebbles were collected at twenty sites located at varying distances from two small sulfide deposits in the central Virginia Piedmont, U.S.A. Mineralization, which is mostly subsurface, consists of pyrite, pyrrhotite, sphalerite and chalcopyrite. The area is rural, forested, and is essentially undisturbed by mining so that natural geochemical trends should be intact. Mineralization could be detected in all three sample types, but trends are subtle, resulting in considerable overlap between samples collected near mineralization and those not associated with mineralized zones. Based on calculated t-values, the most consistent trends are for Cu in the stream water and Fe in the coatings, both of which tend to be higher near mineralization. A sequential selective extraction procedure was used to determine the partitioning of Cu, Zn, Mn and Fe among phases comprising coating samples. Only slight differences in partitioning with proximity to the sulfide deposits could be discerned, too small to be useful in exploration; however, by expressing metal concentrations resulting from certain of these extractions, as ratios, contrast can be increased. In particular, hydrogen peroxide Zn/Mn) and hydroxylamine hydrochloride (Zn/Mn, Cu/Mn and Cu/Fe) produce greater useful contrasts, as defined by calculated t-values, than those which result from total dissolution of coatings, analysis of stream water, or fine-grained sediment.