cssi/SciSciGPT-SciSciNet huggingface dataset:
Social Networks and Educational Opportunity

This chapter reviews the basic structures of social networks and how they have been used to study interrelationships in schools, most prominently those among teachers and students. Part of this discussion includes how network structures are visualized, with multiple examples. These graphic representations demonstrate how information flows in social organizations and is influenced by interactions with colleagues and personalized selections. One of the most important contributions of network analysis is the ability to visualize influence and how inferences of influence can be determined. Influence modeling shows how actors change behaviors in response to others. Selection models show how actors choose with whom they wish to interact and allocate their resources. Finally, this work shows how network forces can facilitate learning by creating opportunities and regulating specific practices. This is particularly beneficial for modeling interactions of teachers within schools and understanding how interactions among teachers and administrators create norms and conditions that can promote or impede reforms within schools. Teacher networks can be especially useful in the formation of learning communities and can enhance effective teaching. But networks also exist outside of school, and the final section of the chapter discusses the emergence of virtual social networks and how professionals are interacting and using them.
Statistical models for meal-level estimation of mass and energy intake using features derived from video observation and a chewing sensor

Accurate and objective assessment of energy intake remains an ongoing problem. We used features derived from annotated video observation and a chewing sensor to predict mass and energy intake during a meal without participant self-report. 30 participants each consumed 4 different meals in a laboratory setting and wore a chewing sensor while being videotaped. Subject-independent models were derived from bite, chew, and swallow features obtained from either video observation or information extracted from the chewing sensor. With multiple regression analysis, a forward selection procedure was used to choose the best model. The best estimates of meal mass and energy intake had (mean ± standard deviation) absolute percentage errors of 25.2% ± 18.9% and 30.1% ± 33.8%, respectively, and mean ± standard deviation estimation errors of −17.7 ± 226.9 g and −6.1 ± 273.8 kcal using features derived from both video observations and sensor data. Both video annotation and sensor-derived features may be utilized to objectively quantify energy intake.
Energy Balance in Cell Phone Radiofrequency Radiation Exposed Mice and Rats

The National Toxicology Program exposed mice and rats to cell phone radiofrequency radiation. They observer cancers in male rats but not in male mice and different increases in body temperature between mice and rats using identical frequency and intensity exposures. Using the Faraday's Law model, thermoregulation considerations and an energy balance equation, we estimate that the increase in temperature of neural circuits of mice exposed to radiofrequency radiation is only 0.28 that of rats. This decrease in neural circuit temperatures is consistent with the absence of cancer in mice. This calculation also qualitatively explains the different increases in body temperature in mice and rats under different radiofrequency intensities and frequencies.
Racial Differences in Performance-Based Function and Potential Explanatory Factors Among Individuals With Knee Osteoarthritis

Objective In individuals with knee osteoarthritis (OA), self-reported physical function is poorer in African Americans than in whites, but whether this difference holds true for objective assessments is unclear. The purpose of this study was to examine racial differences in performance-based physical function as well as potential underlying factors contributing to these racial differences. Methods Participants with knee OA from a randomized controlled trial completed the 2-minute step test (2MST), timed-up-and-go (TUG), and 30-second chair stand (30s-CST) at baseline. Race differences in performance-based function were assessed by logistic regression. Separate models were adjusted for sets of demographic, socioeconomic, psychological health, and physical health variables. Results In individuals with knee OA (n = 322; 72% women, 22% African American, mean ± SD age 66 ± 11 years, mean ± SD body mass index 31 ± 8 kg/m2 ), African Americans (versus whites) had greater unadjusted odds of poorer function (30s-CST odds ratio [OR] 2.79 [95% confidence interval (95% CI) 1.65-4.72], 2MST OR 2.37 [95% CI 1.40-4.03], and TUG OR 3.71 [95% CI 2.16-6.36]). Relationships were maintained when adjusted for demographic and psychological health covariates, but they were either partially attenuated or nonsignificant when adjusted for physical health and socioeconomic covariates. Conclusion African American adults with knee OA had poorer unadjusted performance-based function than whites. Physical health and socioeconomic characteristics diminished these differences, emphasizing the fact that these factors may be important to consider in mitigating racial disparities in function.
"The Headstrong Historian": Writing with Things Fall Apart

Chimamanda Ngozi Adichie's "The Headstrong Historian" is a complex revisioning, completion, and extension of Chinua Achebe's Things Fall Apart. A narratological analysis employing Gerard Genette's theories reveals the numerous ways in which Adichie deepens and extends Achebe's legacy, and, in doing so, complicates his account of African identity and history. With significant repetitions and variations in events, characters, and action, Adichie's story develops its source text in areas such as gender, religion, and history. The text's handling of temporality and focalization demonstrates how history involves the future as well as the past. "The Headstrong His- torian," thus, presents what Paul Ricoeur calls "human time" as a shared experience in which the traces left by the lives of past generations can be located and drawn on during our continual move into the future.
An Electronic Date Market with Sellers' Consortium in Saudi Arabia: A Mathematical Model and Simulation

Dates are an essential commodity in Saudi Arabia. Date trading markets take the form of traditional auction markets. Dates are perishable goods which need to be traded quickly. An electronic market will allow dates traders easier market participation opportunities with respect to time and geographic distance. For efficient trading, a math model with a sellers' consortium is proposed; this math model is simulated by Anylogic simulation software with a heuristic algorithm. This paper explores the possibility of trading with the sellers' consortium. Furthermore, small sellers' consortia and individual large sellers can form a date market and supply the product more efficiently. A sellers' consortium is implemented in the model, and it demonstrated an improved trading performance compared to the same market without consortium.
Utility of Esophagrams to Detect Prevertebral Invasion in Hypopharyngeal Squamous Cell Carcinoma.

OBJECTIVES/HYPOTHESIS Prevertebral fascia invasion is a feature of advanced hypopharyngeal squamous cell carcinoma (HPSCC) that predicts surgical futility. Magnetic resonance and computed topography imaging are used to identify prevertebral involvement, but reliable prediction remains a challenge. Our aims were to describe a new indication for esophagrams and assess its ability to detect prevertebral invasion preoperatively. STUDY DESIGN Retrospective Review. METHODS A retrospective review of advanced HPSCC patients from 2001 to 2019. Thirty-one patients underwent curative treatment (21 surgically, 10 with chemoradiation) with a preoperative esophagram. Operative and pathology reports, and fluoroscopic images were collected from the medical record. Esophagrams were read independently by two blinded radiologists. Excursion of the laryngeal complex was quantified relative to the height of vertebral bodies; <0.5 bodies was considered positive for fixation. Surgery or comparative imaging modalities were the gold-standard comparisons. RESULTS Mean age at diagnosis was 63 years. Twenty-one patients underwent surgical treatment with laryngopharyngectomies. One patient had prevertebral invasion during surgical exploration. Ten patients underwent chemoradiation therapy, and three of these had prevertebral invasion. The average hyolaryngeal elevation was 1.05 vertebral bodies (standard deviation = 0.5). There was a strong correlation between radiologists (R = 0.80, P < .0001). Compared to the gold standard, esophagrams had sensitivity of 75%, specificity of 93%, positive predictive value of 60%, and a negative predictive value (NPV) of 96%. CONCLUSIONS This study highlights the utility of a common radiologic modality in assessing prevertebral fascia invasion in an advanced-stage HPSCC cohort undergoing surgical treatment. With a high NPV and specificity, the esophagram's potential to rule out prevertebral fascia invasion is a useful predictor of resectability. LEVEL OF EVIDENCE 4 Laryngoscope, 131:800-805, 2021.
Updates on the diagnosis and management of the most common hereditary porphyrias: AIP and EPP

The porphyrias are a family of metabolic disorders caused by defects in the activity of one of the enzymes in the heme biosynthetic pathway. Acute intermittent porphyria (AIP), caused by autosomal dominant mutations in the gene encoding hydroxymethylbilane synthase, can lead to hepatocyte overaccumulation and systemic distribution of the proximal porphyrin precursors, 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). ALA and PBG are toxic to neurons and extrahepatic tissue and cause the neurovisceral clinical manifestations of AIP. Management of AIP includes awareness and avoidance of triggering factors, infusions of hemin for severe acute attacks, and, if indicated for chronic suppressive therapy, maintenance treatment with hemin or givosiran, a small interfering RNA molecule that antagonizes ALA synthase 1 transcripts. Erythropoietic protoporphyria (EPP) is most commonly caused by autosomal recessive mutations in the gene encoding ferrochelatase (FECH), the heme pathway terminal enzyme. FECH deficiency leads to erythrocyte overaccumulation and high plasma levels of lipophilic protoporphyrins that photoactivate in the skin, causing burning pain and erythema. Protoporphyrins excreted in the bile can cause gallstones, cholestasis, fibrosis, and ultimately liver failure. Management of EPP includes skin protection and afamelanotide, an α-melanocyte stimulating hormone analog that increases melanin pigment and reduces photoactivation. Liver transplantation may be necessary for severe EPP-induced liver complications. Because AIP and EPP arise from defects in the heme biosynthetic pathway, hematologists are often consulted to evaluate and manage suspected or proven porphyrias. A working knowledge of these disorders increases our confidence and effectiveness as consultants and medical providers.
The human leukocyte antigen as a candidate tumor suppressor

Here we argue in support of the human leukocyte antigen (HLA) supergene as a tumor suppressor. HLA is a recurring mutational target in a large and diverse group of malignancies. The tumor suppressor function of HLA is linked to an embryonic/stemness and drug resistance phenotype. A deeper understanding of the distinct roles of HLA, including immunosurveillance, stemness, and tumor suppressor functions, could illuminate the limited responses in cancer patients. Furthermore, it would provide guidelines for the design of new therapeutic strategies, including the potential of modulating HLA expression in the tumor stem cell compartment.
GRU-DF: A Temporal Model with Dynamic Imputation for Missing Target Values in Longitudinal Patient Data

Temporal models are desirable in studying progressive diseases because the data are typically collected at regular time intervals. However, such clinical data often contain many missing entries, including those from the target variable that we are interested in predicting. Standard imputation techniques (e.g., linear interpolation) are inappropriate in treating missing target observations because they approximate the missing entries before the onset of model training and, thus, would inevitably lead to training a self-fulfilling model. The absence of target observations is particularly problematic for time series data where their availability at each time step is indispensable in building a temporal model. We propose a novel approach that incorporates the missing target value imputation into the training process of the Gated Recurrent Unit (GRU) model. We evaluate our new model in our motivating domain of predicting disease progression of multiple sclerosis patients using a real-world dataset of 508 subjects. The goal is to forecast patients’ disability levels based on data collected in six-month intervals. Our model demonstrates a 27.9% performance gain over a GRU model with a standard forward-fill treatment for the missing target observations. Additionally, our model displays a 21.6% advantage over a non-temporal approach for our machine learning task.
Mechanistic Modeling of Major Offshore CO 2 Well or Pipeline Leakage

Risk assessment of offshore geologic carbon sequestration (GCS) requires quantification of the impacts (consequences) of potential loss-of-containment (LOC) incidents. We have used two mechanistic models to simulate a hypothetical major CO2 well blowout scenario in shallow water off the Texas Gulf Coast. The scenario we consider represents a very rare blowout incident at a prototypical future near-offshore (shallow water) CO2 storage site. The coupled reservoir-well model (T2Well) was used to simulate a large subsea CO2 blowout flow rate from a hypothetical pipeline/wellhead failure for input to an integral model (TAMOC) for simulating CO2 transport in the water column. T2Well couples two-phase Darcy flow in the subsea reservoir with two-phase pipe flow in the well modeled by the drift-flux model. TAMOC is a multipurpose modeling suite that uses an integral approach to model the buoyant bubble plume and entrained sea water. Results of the mechanistic modeling of CO2 transport in the water column by TAMOC suggest that this major CO2 blowout (flow rate more than 1 million tonnes/yr) in ≥50 m of water will be almost entirely attenuated by the water column due to CO2 dissolution into seawater during upward rise. In contrast, the same blowout in 10 m of water will hardly be attenuated at all. The travel time for CO2 from the hole in the pipe to the surface is 0.065 s in the 10 m case, whereas it takes approximately 5 s for the small fraction of CO2 that does not dissolve to make it to the surface in the 50 m water column case. These results are in broad agreement with other field and modeling-based studies.
Supported Decision-Making for People with Dementia Should Focus on Their Values.

In their thoughtful and rigorous article, Peterson and colleagues (2021) extend an account of supported decision-making that was originally developed for people with static cognitive impairments, t...
Social Choice and Legitimacy: The Possibilities of Impossibility

Governing requires choices, and hence trade-offs between conflicting goals or criteria. This book asserts that legitimate governance requires explanations for such trade-offs and then demonstrates that such explanations can always be found, though not for every possible choice. In so doing, John W. Patty and Elizabeth Maggie Penn use the tools of social choice theory to provide a new and discriminating theory of legitimacy. In contrast with both earlier critics and defenders of social choice theory, Patty and Penn argue that the classic impossibility theorems of Arrow, Gibbard, and Satterthwaite are inescapably relevant to, and indeed justify, democratic institutions. Specifically, these institutions exist to do more than simply make policy - through their procedures and proceedings, these institutions make sense of the trade-offs required when controversial policy decisions must be made.
Frequency Domain Synthesis of Optimal Inputs for Adaptive Identification and Control

In this paper, we precisely formulate the input design problem of choosing proper inputs for use in SISO Adaptive Identification and Model Reference Adaptive Conrol algorithms. Characterization of the optimal inputs is given in the frequency domain and is arrived at through the use of averaging theory. An expression for what we call the average information matrix is derived and its properties are studied. To solve the input design problem, we recast the design problem in the form of an optimization problem which maximizes the smallest eigenvalue of the average information matrix over power constrained signals. A convergent numerical algorithm is provided to obtain the global optimal solution. In the case where the plant has unmodelled dynamics, a careful study of the robustness of both Adaptive Identification and Model Reference Adaptive Control algorithms is performed using averaging theory. With these results, we derive a bound on the frequency search range required in the design algorithm in terms of the desired performance.
Spamscatter: characterizing internet scam hosting infrastructure

Unsolicited bulk e-mail, or SPAM, is a means to an end. For virtually all such messages, the intent is to attract the recipient into entering a commercial transaction -- typically via a linked Web site. While the prodigious infrastructure used to pump out billions of such solicitations is essential, the engine driving this process is ultimately the "point-of-sale" -- the various money-making "scams" that extract value from Internet users. In the hopes of better understanding the business pressures exerted on spammers, this paper focuses squarely on the Internet infrastructure used to host and support such scams. We describe an opportunistic measurement technique called spamscatter that mines emails in real-time, follows the embedded link structure, and automatically clusters the destination Web sites using image shingling to capture graphical similarity between rendered sites. We have implemented this approach on a large real-time spam feed (over 1M messages per week) and have identified and analyzed over 2,000 distinct scams on 7,000 distinct servers.
Duodenal ulcer with unexplained marked basal gastric acid hypersecretion.

Abstract Out of 1012 gastric analyses performed in 6 yr, 40 persons had basal acid output ≥ 15 mmol/hr. Of these, 8 had known causes for hypersecretion (6 had Zollinger-Ellison syndrome and 2 systemic mastocytosis); 1 died before further study, leaving 31 with unexplained basal acid hypersecretion (19.5 ± 0.60 mmol/hr) and peptic ulcer (30 duodenal ulcer and 1 gastric ulcer). All were male compared with the 72:28 M : F ratio in the duodenal ulcer population from which these were drawn. From among the same 1012 patients 29 male controls with duodenal ulcer and basal acid output 0.1). In controls basal acid output was related to body weight (r = 0.65) but in the hypersecretors it was not (r = 0.11). In the hypersecretors, however, basal acid output was related to length of ulcer history (r = 0.71), but in the controls it was not (r = 0.06). A significant cholinergic contribution to the hypersecretion was inferred from >90% reduction by either atropine (15 μg/kg) or vagotomy in all 12 of the 31 hypersecretion subjects who were so studied. The clinical course of the two groups was not different as regards number of hospitalizations, episodes of bleeding, number of operations, number of perforations or obstruction, and the same proportion (931 vs.829) remained free of complications during the average 12.5-yr period of total ulcer history. The finding of massive basal acid hypersecretion does not necessarily imply a Zollinger-Ellison syndrome nor call for unusually extensive surgery for peptic ulcer, vagotomy being sufficient to correct the hypersecretion.
Radioimmunolocalization of Metastatic Breast Carcinoma Using Indium-111-Methyl Benzyl DTPA BrE-3 Monoclonal Antibody: Phase I Study

Pharmacokinetics of radiolabeled BrE3 monoclonal antibody (Mab), reactive against a breast mucin epitope, were assessed in 15 patients with advanced breast cancer. Patients received 5 mCi (185 MBq) of 111In-methyl benzyl isothiocyanate DTPA (MX-DTPA) conjugated BrE-3 Mab intravenously with total antibody doses of 10, 50 or 100 mg. Serial quantitative imaging, blood and urine clearance were obtained to measure pharmacokinetics, assess tumor localization and estimate radiation dose. Organ function was followed to determine toxicity. Mild allergic reactions occurred in four patients. Eighty-six percent of 70 known lesions and 5 unsuspected lesions were detected by antibody imaging. Biexponential modeling of radiolabeled antibody in serum showed a T1/2 alpha = 9.5 +/- 2.7 hr and T1/2 beta = 56 +/- 25.4 hr. Total urinary excretion averaged 35.5% +/- 19.3% injected dose (ID) by Day 8. Quantitative imaging showed that 0.02-2.56% ID localized in tumors. Extrapolating dosimetry from 111In-MX-DTPA-BrE-3 to 90Y-MX-DTPA-BrE-3, we estimate therapeutic radiation doses could be delivered to some tumors with tolerable toxicity.
Differences in weight-related behavioral profiles by sexual orientation among college men: A latent class analysis

Abstract Purpose. To identify and describe homogenous classes of male college students based on their weight-related behaviors (e.g., eating habits, physical activity, and unhealthy weight control) and to examine differences by sexual orientation. Design. Study design was a cross-sectional sample of 2- and 4-year college students. Setting. Study setting was forty-six 2- and 4-year colleges in Minnesota. Subjects. Study subjects comprised 10,406 college males. Measures. Measures were five categories of sexual orientation derived from self-reported sexual identity and behavior (heterosexual, discordant heterosexual [identifies as heterosexual and engages in same-sex sexual behavior], gay, bisexual, and unsure) and nine weight-related behaviors (including measures for eating habits, physical activity, and unhealthy weight control). Analysis. Latent class models were fit for each of the five sexual orientation groups, using the nine weight-related behaviors. Results. Overall, four classes were identified: “he...
Ionic equilibria in ferric sulfate-sulfuric acid solutions

Abstract The ionic equilibria of ferric sulfate-sulfuric acid aqueous solution are modeled mathematically, taking into account the effect of ionic strength. Results of this analysis indicate that ion interactions can significantly change the ionic concentration of the solutions which could lead to errors in the evaluation of data on iron(III) extraction kinetics or equilibrium.
Foliar sorption of atmospheric sulphur dioxide by woody plants

Abstract Foliar uptake of ambient sulphur dioxide (1·0 ppm) was measured in an openfumigation system. Container-grown seedlings of white birch ( Betula papyrifera Marsh.), red maple ( Acer rubrum L.), white ash ( Fraxinus americana L.), sweetgum ( Liquidambar styraciflua L.), rosebay rhododendron ( Rhododendron maximum L.), kurume azalea ( Rhododendron obtusum japonicum Wils. cv. Venus), privet ( Ligustrum vulgare L.), and firethorn ( Pyracantha angustifolia (Franch.) Schneid.) were used in the study. Maple, birch and sweetgum showed appreciably greater vegetal sorption of sulphur dioxide on a unit area or unit weight basis than did comparable species of rhododendron, ash, and azalea. Privet and firethorn showed an intermediate response. Under controlled environmental conditions, depletion of sulphur dioxide by foliage of firethorn remained relatively constant for periods up to 6 h. There was no significant difference in the capacity of foliage from white ash and azalea to remove sulphur dioxide from the air at pollutant concentrations of 1·0, 0·5 and 0·2 ppm. However, leaves of birch and firethorn showed significantly less SO 2 uptake at 0·2 ppm compared with uptake at the higher concentrations. The data show that foliage of certain woody plants may significantly reduce ambient sulphur dioxide levels in the microenvironment immediately surrounding individual leaves.
Metabolism of a Representative Oxygenated Polycyclic Aromatic Hydrocarbon (PAH) Phenanthrene-9,10-quinone in Human Hepatoma (HepG2) Cells

Exposure to polycyclic aromatic hydrocarbons (PAHs) in the food chain is the major human health hazard associated with the Deepwater Horizon oil spill. Phenanthrene is a representative PAH present in crude oil, and it undergoes biological transformation, photooxidation, and chemical oxidation to produce its signature oxygenated derivative, phenanthrene-9,10-quinone. We report the downstream metabolic fate of phenanthrene-9,10-quinone in HepG2 cells. The structures of the metabolites were identified by HPLC–UV–fluorescence detection and LC–MS/MS. O-mono-Glucuronosyl-phenanthrene-9,10-catechol was identified, as reported previously. A novel bis-conjugate, O-mono-methyl-O-mono-sulfonated-phenanthrene-9,10-catechol, was discovered for the first time, and evidence for both of its precursor mono conjugates was obtained. The identities of these four metabolites were unequivocally validated by comparison to authentic enzymatically synthesized standards. Evidence was also obtained for a minor metabolic pathway of ...
Numerical integration of linear integral equations with mild discontinuity

Indefinite integrals of the form $$\mathop \smallint \limits_0^s (s - t)^\ell x(t) dt, 0\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \leqslant } s\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \leqslant } 1$$ are approximated by sums of the form $$\Sigma \omega _{\ell ni} (s) x(t_{ni} ),$$ and error bounds are found. Applications are made to linear integral equations with mild discontinuities. Examples are given.
A comparative evaluation of ketamine anesthesia in children and adults.

Seven per cent of patients less than 31 years old who received ketamine anesthesia developed problems leading to unsatisfactory anesthetic courses (loss of airway, muscular hypertonus, and inadequate analgesia); 34 per cent of patients 31 years old or older had unsatisfactory anesthesia. Emergence reactions (not classified as unsatisfactory anesthesia) occurred in 24 per cent of patients 16 years old or older and in 8 per cent of children less than 16 years old.
Interaction of U6 snRNA with a sequence required for function of the nematode SL RNA in trans-splicing

Nematode trans-spliced leader (SL) RNAs are composed of two domains, an exon [the 22-nucleotide spliced leader] and a small nuclear RNA (snRNA)-like sequence. Participation in vitro of the spliced leader RNA in trans-splicing reactions is independent of the exon sequence or size and instead depends on features contained in the snRNA-like domain of the molecule. Chemical modification interference analysis has revealed that two short sequence elements in the snRNA-like domain are necessary for SL RNA activity. These elements are sufficient for such activity because when added to a 72-nucleotide fragment of a nematode U1 snRNA, this hybrid RNA could participate in trans-splicing reactions in vitro. One of the critical sequence elements may function by base-pairing with U6 snRNA, an essential U snRNA for both cis- and trans-splicing.
Integrating Dynamic Force Spectroscopy and Surface Plasmon Resonance to Define the Energy Landscape for Integrin:Ligand Binding

Background: Blood clots, aggregates of platelets trapped in a mesh of fibrin fibers, can impede normal blood flow, causing heart attacks and strokes. Therapeutic interventions use drugs with Arg-Gly-Asp (RGD) sequences to disrupt interactions between platelet αIIbβ3 integrins and the fibrin network's subunits. Determination of the αIIbβ3-ligand energy landscape will elucidate the successes and limitations of integrin antagonists.Objectives: Integrating surface plasmon resonance (SPR) and dynamic force spectroscopy (DFS), we studied the energetics of αIIbβ3: ligand interactions. We focused on cHArGD, a cyclic peptide structurally similar to eptifibatide, a cardiovascular disease drug, as well as to fibrinogen's KQAGDV integrin-recognition sequence.Methods: DFS determined single bond rupture forces, the dissociation constant koff, and the rupture distance x-1 for αIIbβ3: cHArGD interactions. SPR determined the kinetic and thermodynamic parameters for αIIbβ3: cHArGD binding.Results: DFS performed at three different pulling rates (14000, 42000, and 70000) pN/s) yielded rupture forces of 77, 86 and 88 pN; Bell model analysis yielded a dissociation constant, koff ∼ 0.03 sec−1 and rupture distance x-1∼ 0.6 nm. Excess cHArGD in solution dramatically reduced the rupture forces, confirming specificity. SPR yielded kon ∼ 7000 L/mol-sec and koff ∼ 0.01 sec−1 at 25 °C. SPR equilibrium and transition state thermodynamic data, obtained at 15 - 37 °C, show that αIIbβ3:cHArGD interactions must overcome an entropy-unfavorable activation energy barrier (ΔGao‡ 12 kcal/mol) before gaining a favorable ΔH and ΔS for binding (ΔG° - 8 kcal/mol).Conclusions: SPR and DFS gave comparable dissociation rates for αIIbβ3:cHArGD interactions and a critical rupture distance that agrees with the dimensions of the complementary electrostatic contacts shared by all integrin:RGD complexes. Our energy landscape adds a nanoscale to the mechanisms that regulate αIIbβ3's interactions with pharmacological and physiological ligands.
An integrated STEM learning model for high school in engineering education

The primary driving force of the US economy depends on the advancement of Science, Technology, Engineering and Mathematics (STEM). Historically, the “E” of STEM has been virtually silent in U.S. elementary and secondary schools. In recent years, K-12 engineering education started to gain attention from educators and policy makers. However, there is a strong need for more standardized engineering curriculum and assessment in K-12 classrooms across the country. It is imperative that more efforts are introduced at the local, district, and federal level that help create strategies, education reforms and opportunities to boost the current meagre national STEM talent pool for a sustained U.S. economy and meet the STEM workforce demands by the year 2020. It is imperative that more efforts are introduced at local, districts, and federal level that helps create strategies, education reforms and opportunities to boost the current meagre national STEM talent pool for a sustained US economy and meet the STEM workforce demands by the year 2020. a team of experts was convened by the NRC at the request of Representative Frank Wolf (VA) to identify highly STEM focused K-12 schools and programs across the country, however this was focused on the science and mathematics of STEM. The National Oceanic and Atmospheric Administration-Cooperative Remote Sensing Science and Technology Center at the City College of the City University of New York funded by NOAA's Educational Partnership Program created a unique project-based integrated STEM learning model that introduces an holistic learning approach to instill college-readiness and STEM motivation among HS students especially students of color and underserved communities.
Isolation, identification, synthesis and biological activity of volatile compounds from the heads of Atta ants.

Abstract S-(+)-4-methyl-3-heptanone has been identified as the principal alarm pheromone of Atta texana and Atta cephalotes . Both enantiomers of 4-methyl-3-heptanone have been synthesized and their biological activities have been compared on both species of ants. Comparison of the geometric averages of response ratios, at threshold concentration levels on A. texana , showed S-(+)-4-methyl-3-heptanone to be about 100 times more active than the (−) enantiomer. A similar analysis also showed no inhibition of the activity of S-(+)-4-methyl-3-heptanone by the (−) enantiomer. A less rigorous study on A. cephalotes showed S-(+)-4-methyl-3-heptanone to be about 210 times more active than R-(−)-4-methyl-3-heptanone. Both ant species produce 3-octanone, possible trace amounts of 3-octanol, and both diastereomers of 4-methyl-3-heptanol. A. texana also produces (+)-2-heptanol, 2-heptanone, and 3-heptanol. A. cephalotes contains trace amounts of 2-heptanone.
Factor Analysis and Artifact Typology

The general utility of r-mode factor analyses for screening and ordering artifact characteristics is severely restricted by the presence of nominal categories in typological attribute systems. Even where a correlation coefficient appropriate to qualitative data can be used, factor analysis generates spurious correlations stemming from the interdependencies that nominal attributes usually share. The resulting factors may also obscure or distort the contingent interactions that can strongly influence typological patterning, especially among lithic artifacts. R. A. Benfer's factor analysis of stone projectile points illustrates these problems, in addition to yielding factors that largely reflect the redundancy with which certain aspects of typological variation are expressed in his raw data. [factor analysis, statistics, artifact typology, archeology]
Impact of nuchal translucency credentialing by the FMF, the NTQR or both on screening distributions and performance

Objective In the USA, both The Fetal Medicine Foundation (FMF) and the Nuchal Translucency Quality Review Program (NTQR) have operated education, review and credentialing for physicians and sonographers for the measurement of nuchal translucency (NT). We sought to assess differences in the distribution of NT measurements based upon the system from which the operator obtained their education, review and credentialing. Methods 398 311 NT measurements by 1541 sonographers who had performed ≥ 50 exams from July 2008 to June 2010 were grouped by organization. Differences between grouped measurements were assessed using analysis of variance of log10NT multiples of the median (MoM), with sonographer and organization as factors. Results MoM values were significantly lower (P⩽0.001) and SD was significantly higher (P < 0.001) for the NTQR group compared with the FMF group or those sonographers credentialed by both. The percentage of individuals with negative bias ≥ 10% was greater for the NTQR group (P < 0.001). The difference was less but still significant (P = 0.009) when bias was adjusted for by the overall median for the organization. Conclusions Although NT MoM measurements were significantly lower and had a wider variance when obtained by the NTQR group, our data cannot distinguish between bias in training or the attributes of the participating sonographers in each program. With these large numbers, it is unlikely that patient characteristics could explain the discrepancy in distributions. Ongoing efforts to monitor sonographer performance with remediation for poor performers may reduce discrepancies between organizations. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Post‐Traumatic Headaches: Commentary: Clinical Characteristics, Comorbidity, and Treatment

Objective: To establish the prevalence of post-traumatic headache, persisting at 3 months following minor traumatic brain injury. Design: A prospective controlled study of patients admitted with a diagnosis of mild traumatic brain injury and matched orthopedic controls over 12 months during 2004. Setting: A level 2 inner city Emergency Department in Sydney, Australia. Patients: One hundred eligible sequential admissions with mild traumatic brain injury as defined by American Congress of Rehabilitation Medicine, 1993, and 100 matched minor injury controls with nondeceleration injuries. Interventions: Subjects were part of a study on prediction of postconcussive syndrome and had neuropsychological tests, balance test, and pain recordings taken at the time of injury, at 1 month, and at 3 months post-injury. Outcome Measures: Main measures were the reporting of headache "worse than prior to the injury" and concordant with the definition of Post-traumatic Headache according to International Headache Society Classification of Headache Disorders 2003. Results: 15.34% of those with minor head injury continued to complain of persistent post-traumatic headache at 3 months compared to 2.2% of the minor injury controls. Conclusions: To the authors' knowledge this is the first [Australian] controlled prospective study in the prevalence of post-traumatic headache following mild traumatic brain injury.
Nicotine enhances both foreground and background contextual fear conditioning

The present study examined if nicotine enhances contextual fear conditioning when the training context is either a background stimulus or a foreground stimulus. In the background conditioning experiment, mice were trained using two auditory conditioned stimulus (CS; 30 s, 85 dB white noise)–footshock unconditioned stimulus (US; 2 s, 0.57 mA) pairings and tested 24 h later. In the foreground conditioning experiment, mice were trained with two presentations of a footshock US (2 s, 0.57 mA) and tested 24 h later. Mice received 0.09 mg/kg nicotine before training and testing. For both the foreground and background conditioning experiments, nicotine enhanced contextual conditioning. No enhancement of the auditory CS–US association was seen. These results demonstrate that nicotine enhances contextual fear conditioning regardless of whether the context is a background stimulus or a foreground stimulus during conditioning.
The effective use of acai juice, blueberry juice and pineapple juice as negative contrast agents for magnetic resonance cholangiopancreatography in children

Magnetic resonance cholangiopancreatography (MRCP) is commonly performed in the evaluation of known or suspected pancreaticobiliary disease in children. The administration of a negative oral contrast agent can improve the quality of the examination without significant additional cost. We describe our experience with certain brands of acai juice, blueberry juice and pineapple juice as negative oral contrast agents in children. We believe these fruit juices are safe, palatable and may improve MRCP image quality.
The enteric parasite Entamoeba uses an autocrine catecholamine system during differentiation into the infectious cyst stage.

Enteric amoebae of the genusEntamoeba travel from host to host in an encysted form. We previously showed that in vitro cyst development ofEntamoeba invadens requires the addition of defined amounts of multivalent galactose-terminated molecules, such as mucin, to the cultures. The amoeba surface lectin that binds mucin is presumed to convey transmembrane signals when clustered by the ligand, but the signaling molecules that function downstream of the lectin are not known. We report here that Entamoebaencystation was induced in the absence of galactose ligand when catecholamines were added to the encystation medium. Micromolar amounts of both epinephrine and norepinephrine induced encystation. Of a variety of synthetic catecholamine agonists tested, only β1-adrenergic receptor agonists supported encystation, whereas α- and β2-adrenergic receptor agonists did not. Only β1-adrenergic receptor antagonists inhibited encystation, and did so even when exogenous catecholamines were not added, indicating that catecholamine binding is required for encystation and suggesting an endogenous source of the ligand. High performance liquid chromatography analysis of Entamoebaextracts showed that the amoebae themselves contain catecholamines and at least one of these is released when the cells are stimulated to encyst with galactose-terminated ligands. The presence of catecholamine binding sites on the surface of amoeba trophozoites was confirmed using radiolabeled catecholamine antagonist. Amoeba encystment was inhibited by addition of β1-adrenergic receptor antagonist to cells that were stimulated to differentiate with either galactose ligand or catecholamines, but not with dibutyryl cAMP. This suggests that the amoeba catecholamine receptor functions downstream of the galactose lectin and upstream of adenylyl cyclase. This enteric protozoan parasite, therefore, contains the components of an autocrine catecholamine ligand-receptor system that may act in conjunction with a galactose lectin to regulate differentiation into the infectious cyst stage.
Radiation Damage Effects by Electrons, Protons, and Neutrons in Si(Li) Detectors

The degradation of performance of lithium-compensated silicon nuclear particle detectors induced by irradiation at room temperature with 0.6-MeV and 1.5-MeV electrons, l.9-MeV protons, and "fast" neutrons from a plutonium-beryllium [Pu-Be] source has been investigated. In general with increasing fluence, the irradiations produced an increase of detector leakage current, noise, capacitance, and a degradation in the performance of the detector as a charged-particle energy spectrometer. Following the irradiations, annealing effects were observed when the detectors were reverse-biased at their recommended operating voltages. Upon removal of bias, a continuous degradation of detector performance characteristics occurred. Detectors which had been damaged by electrons and protons exhibited a stabilization in their characteristics within two weeks after irradiation, whereas detectors damaged by neutrons had a continuous degradation of performance over a period of several months.
Strangeness matrix elements in the nucleon

Abstract We investigate the strangeness “content” of the proton in three nucleonic models: a simple relativistic meson-loop picture, a naive nonrelativistic quark model with mesons, and an extended cloudy bag model. In each case, pseudoscalar mesons are included. Nucleon matrix elements involving strange quarks are generated through the formation of a kaon cloud. We concentrate on the last two models, with the one free parameter chosen to reproduce the electromagnetic nucleon observables. We give theoretical predictions for F 2 s (0), the strange quark contribution to the weak magnetic form factor, 〈 r 2 〉 s , the strangeness radius of the nucleon, and g A s , the strangeness axial vector matrix element. We observe a strong dependence of the strange quark matrix elements on the choice of the momentum cutoff or bag size.
Daily gastrointestinal symptoms in women with and without a diagnosis of IBS.

This study compared daily gastrointestinal symptoms and stool characteristics across two menstrual cycles, and recalled bowel symptoms and psychological distress in women with irritable bowel syndrome (IBS,N=22), IBS nonpatients (IBS-NP,N=22), and controls (N =25). Daily reports of abdominal pain, bloating, intestinal gas, constipation, and diarrhea did not differ significantly between the IBS and IBS-NP groups but both groups reported significantly higher symptoms than the control group. Stool consistencies was significantly looser in the IBS group relative to the control group. Menstrual cycle effects on symptoms were noted in all the groups. There were no significant differences in psychological distress between women with IBS, and IBS-NP, but both groups reported significantly higher global distress than the control group. The lack of difference between the IBS and IBS-NP groups in contrast to the results of others, can be understood in terms of differences in recruitment strategies.
Generation of Influenza Virus from Avian Cells Infected by Salmonella Carrying the Viral Genome

Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 107 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo.
Potential use of diode laser soldering in middle ear reconstruction.

Background and Objectives To assess the potential use of diode laser soldering to improve mechanical stability of middle ear reconstruction. The diode laser with a biological solder may offer benefits over traditional methods. We evaluated the strength of soldered bonds and a means to apply such a technique in the human middle ear. Study Design/Materials and Methods The strength of soldered junctions using fascia, cartilage, bone, and hydroxyappatite was evaluated in vitro. A diode laser (810-nm wavelength) and 50% albumin with 0.1% indocyanine green dye was used. Soldered bonds were compared to those obtained with adhesive alone. A fiberoptic delivery system was evaluated. Ten hydroxyappatite prostheses were soldered to the stapes in human cadaver temporal bones, and the force required to disrupt the bonds were measured. Results Statistically significant greater strength was obtained with soldering. Ossicular prostheses can be effectively secured to the stapes in a cadaver model. Conclusions Soldering techniques show promise in middle ear reconstruction. Lasers Surg. Med. 31:242–246, 2002. © 2002 Wiley-Liss, Inc.
A cyclical model of institutional change

Purpose – Previous research on institutional change has largely ignored its cyclical nature. This paper aims to introduce a four‐phase cyclical model of long‐term institutional change.Design/methodology/approach – The recurrent patterns of the model have been identified from previous technological revolutions and their accompanying surges of development. The model also incorporates generational theory as a driver of institutional change.Findings – The model predicts that a multi‐year institutional crisis is currently underway that has important implications for practitioners. The paper also describes proposed solutions to the current crisis.Originality/value – The model developed synthesizes disparate institutional theories to build a new explanation for long‐term economic development.
Determination of the Momentum Distribution from the Dynamic Structure Factor in Quantum Liquids

Scaling of the dynamic structure factor at high momentum transfer is established by using time-ordered perturbation theory. Whereas the scaling function is the longitudinal momentum distribution for systems interacting with smooth two-body potentials, additional terms contribute in the case of strong short-range repulsion. Illustrative results are presented for a hard-sphere Bose gas and the relevance to electron scattering from nuclei and neutron scattering from liquid helium is discussed.
Least-norm linear programming solution as an unconstrained minimization problem☆

Abstract It is shown that the dual of the problem of minimizing the 2-norm of the primal and dual optimal variables and slacks of a linear program can be transformed into an unconstrained minimization of a convex parameter-free globally differentiable piecewise quadratic function with a Lipschitz continuous gradient. If the slacks are not included in the norm minimization, one obtains a minimization problem with a convex parameter-free quadratic objective function subject to nonnegativity constraints only.