cssi/SciSciGPT-SciSciNet huggingface dataset:
WE‐D‐330D‐02: Non‐Ideal Behavior of DR Systems

Ideally, we would like for clinical digital radiography (DR) systems to produce faithful reproductions of radiographic projections, acquired at optimum gain, and rendered appropriately for diagnostic interpretation. We also expect uniform performance from identical DR systems. We would like DR systems to maintain their optimum performance indefinitely, or at least to alert us when their performance falls below reasonable limits. We expect DR systems to be user‐friendly, to accommodate operator Quality Control (QC) activities, and to enable the operator to correct errors without the need for a repeated exposure. In reality, all DR systems fall short of these ideal expectations. Awareness of causes and corrective actions for non‐ideal behavior is important for Medical Physicists in order to assist clinical practice with DR. The talk will consider the effects of discrete detector elements, gain compensation maps, and “ghost” images on acquisition of the radiographic projection. Variation in gain and SNR with exposure will be discussed. Sources of interferences with image segmentation will be described including hardware, shielding, and the challenge of large and small patients. The influence of operator technical errors will be explored. The value of automated quality control self‐tests in assessing and maintaining optimum performance will be examined. The ability of the operator to intervene in the event of a sub‐standard image will be considered. Positive and negative aspects of operator modification will be mentioned. Discrepancies between display functions at the acquisition station and at the physician's diagnostic display will be discussed. Learning Objectives: 1. Appreciate the technological limitations on ideal behavior by DR systems. 2. Understand the clinical manifestations of non‐ideal DR behavior. 3. Identify actions that can reveal or correct non‐ideal DR behavior.
Congenital Heart Surgery Nomenclature and Database Project: anomalies of the coronary arteries

The extant nomenclature for coronary artery anomalies is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. The seven major categories of coronary artery anomalies are: anomalous pulmonary artery origins of the coronaries, anomalous aortic origins of the coronaries, congenital atresia of the left main coronary artery, coronary artery fistulas, coronary artery bridging, coronary aneurysms, and coronary stenosis. A comprehensive database set is presented which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail, which can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented, which will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.
An approximate method for computing error coefficient matrices for lunar trajectories.

Computation of transition matrices or error coefficients in midcourse guidance studies of lunar trajectories
Ultralow loading Pt nanocatalysts prepared by atomic layer deposition on carbon aerogels.

Using atomic layer deposition (ALD), we show that Pt nanoparticles can be deposited on the inner surfaces of carbon aerogels (CA). The resultant Pt-loaded materials exhibit high catalytic activity for the oxidation of CO even at loading levels as low as ∼0.05 mg Pt/cm2. We observe a conversion efficiency of nearly 100% in the 150−250 °C temperatures range, and the total conversion rate seems to be limited only by the thermal stability of the CA support in ambient oxygen. The ALD approach described here is universal in nature, and can be applied to the design of new catalytic materials for a variety of applications, including fuel cells, hydrogen storage, pollution control, green chemistry, and liquid fuel production.
Characterization of Transcription Initiation Intermediates in Escherichia Coli RNA Polymerase by Fluorescence

Transcription initiation involves a series of conformational changes that are triggered in both RNA polymerase (RNAP) and DNA after recognition of −35, −10 elements of promoter DNA by RNAP holoenzyme, consisting of catalytic core and a specificity factor, σ. RNA polymerase (RNAP) functions as a molecular isomerization machine, binding and bending the promoter DNA in the initial closed complex and using binding free energy to melt 13 bp of DNA in the active site cleft to form an initial unstable open promoter complex, which is converted to a final open complex (RPo) (Saecker et al, '11). Promoter melting is thought to commence upon flipping of −11A of the non-template strand out of the DNA helix (Schroeder et al, '09) but several questions remain open. After recruitment of RNAP to promoter DNA, what conformational changes occur in the complex to put the downstream DNA duplex in the cleft? When and how is the DNA bent and wrapped around RNAP? When does the −11A element rotate vis-a-vis wrapping? To answer these questions, we are characterizing early intermediates at the λPr promoter using equilibrium and kinetic bulk fluorescence measurements. Fluorescence Resonance Energy Transfer (FRET) experiments monitor the extent of wrapping whereas stopped-flow “Beacon” assays provide information about −11A base-flipping and opening of −10 region (Mekler et al, '11). FRET experiments show that promoter DNA is wrapped around RNAP in the advanced closed complex and that wrapping persists in open complexes. The wrapped open complex is found to be transcriptionally competent. Real-time stopped-flow kinetic experiments are in progress to determine the sequence of steps in which upstream and downstream duplex promoter DNA are bent toward and wrapped around RNAP to put the start site region in the cleft and open it.
Health of adolescents: research in school health.

A community analysis and research strategy called Project GENESIS is described in this article. Combining quantitative and qualitative research methods, Project GENESIS emphasizes the qualitative research strategy of ethnography.The purpose of this investigation was to analyze the overall health of the aggregate of teenagers in a moderate sized town in northern Colorado. Data analysis revealed findings related to teen lifestyles, health and health services, substance abuse, and pregnancy. Recommendations to improve the health of teenagers based on the findings are presented. Implications of this type of research for school and community health nursing are discussed.
Connectivity of features in microlens array reduction photolithography: generation of various patterns with a single photomask.

Microlens array photolithography (MAP) is a technique in which arrays of microlenses positioned close to photoresist reduce cm-sized figures on photomasks and form μm-scale images in the photoresis...
Treating AML with ATRA? Beware MN1 !

MN1 overexpression is a negative predictive factor for elderly AML patients receiving ATRA treatment. The paper by Heuser and colleagues in this issue of Blood identifies MN1 as a marker that predicts significantly prolonged event-free survival in elderly patients with acute myeloid leukemia (AML)
DELAYED MATURATION, NEOTENY, AND SOCIAL SYSTEM DIFFERENCES IN TWO MANAKINS OF THE GENUS CHIROXIPHIA

Long-tailed manakins (Chiroxiphia linearis) and swallow-tailed manakins (C. caudata) are closely related, sexually dichromatic, lek-breeding species in which male mating success is highly skewed. Males of both species delay plumage maturation. Before reaching the definitive state, they wear a sequence of feather coats less conspicuous than that of the adult. Nondefinitive plumages probably enhance male survival in the two species; in C. caudata they may also enhance breeding success of young males, who may be fully reproductively mature their first year. In C. linearis testicular development is retarded along with that of plumage, although males may be physiologically capable of breeding prior to the acquisition of the definitive plumage. This difference probably reflects differences in the social systems of the two species. Five hypotheses have been proposed to explain the evolution of delayed plumage maturation. The sexual-selection, cryptic-breeder, and winter-adaptation hypotheses suggest that it functions primarily to enhance survival of young males. The juvenile- and female-mimicry hypotheses emphasize enhancement of immediate mating success. Support is provided for all but the female-mimicry hypothesis; it is argued that data are more consistent with juvenile mimicry and a neotenic origin of nondefinitive plumages.
In vivo 1H-[13C]-NMR spectroscopy of cerebral metabolism.

13C NMR spectroscopy in combination with the infusion of (13)C-labeled precursors is currently the only technique that is capable of quantitatively studying energy metabolism, neurotransmission and other metabolic pathways non-invasively in vivo. (1)H-[(13)C]-NMR spectroscopy is a high-sensitivity alternative to direct (13)C NMR spectroscopy. The development of improved NMR methods for water suppression, spatial localization, broadband decoupling, shimming and signal quantification, together with the availability of high magnetic field strengths, has made (1)H-[(13)C]-NMR spectroscopy the method of choice for the detection of metabolism at a high spatial and/or temporal resolution. (1)H-[(13)C]-NMR spectroscopy can now be used to discriminate glutamatergic (excitatory) and GABAergic (inhibitory) neuronal activity. The improved sensitivity allows the detection of metabolism in different tissues (e.g. gray and white matter) and potentially even in smaller structures, like cortical layers. Finally, (1)H-[(13)C]-NMR spectroscopy allows the detection of energy metabolism and neurotransmission during functional activation, thereby further strengthening our understanding of the neurochemical basis of brain function.
Target zones, reserve crises, and inverted S-curves

Abstract Recent currency crises have focused attention on models of currency crises. Although many models exist, few focus on intermediate exchange rate systems, and fewer describe the interplay between regime choice and vulnerability to crisis. This paper embeds a target zone model (typifying many intermediate regimes) into a first-generation currency crisis model. This paper shows that an inverted S-curve (where a targeted exchange rate is more volatile than its underlying fundamentals) is generally inconsistent with a viable target zone because such a regime would collapse upon speculative attack. This paper describes conditions where a policymaker could ensure a target zone would weakly stabilize exchange rates and thereby maintain short-run viability.
Liver biopsy findings from healthy potential living liver donors: Reasons for disqualification, silent diseases and correlation with liver injury tests

Background/Aims Liver biopsies detect silent donor disease in potential living liver donors and provide material for studies of subclinical non-alcoholic fatty liver disease (NAFLD). Our primary goal was to determine the contribution of biopsy findings to potential donor evaluation. Factors contributing to pre-clinical NAFLD and correlations between liver injury tests and histopathology have been also determined. Methods Patient records, laboratory tests and results of the histopathologic examination and diagnoses of 284 patients from 2001 to 2005 were retrospectively extracted from the EDIT database. Hepatic histology was correlated with liver injury tests and with general demographic characteristics in an otherwise normal healthy population. Results A minority ( n =119; 42%) of biopsies from this population of 143 males/141 females (average age=36.8years; mean BMI=26.6) were completely normal. The remainder showed steatosis ( n =107; 37%), steatohepatitis ( n =44; 15%), or unexplained low-grade/early stage chronic hepatitis, primary biliary cirrhosis, or nodular regenerative hyperplasia ( n =16; 6%). Biopsy findings disqualified 29/56 donors. Independent risk factors for NAFLD by multivariate modeling, which differed by sex, included: BMI ( p =0.0001), age ( p =0.003), iron ( p =0.01), and ALT ( p =0.004). Conclusions Liver biopsies provide valuable information about otherwise undetectable liver disease in potential liver donors. Obesity, age and iron, which are influenced by sex, contribute to NAFLD pathogenesis. Blood tests other than standard liver profiles are needed to detect early NAFLD.
Spectrophotometric determination of formaldehyde by using formaldehyde dehydrogenase

Abstract A new method for the determination of formaldehyde by using formaldehyde dehydrogenase is described. The method is based on the quantitative oxidation of formaldehyde with oxidized nicotinamide adenine dinucleotide (NAD+), in the presence of formaldehyde dehydrogenase, to form the reduced dinucleotide (NADH). This enzyme does not require glutathione as a co-factor and the NADH produced, which is directly proportional to the concentration of formaldehyde in the assay solution, is then measured spectrophotometrically at 340 nm. Formaldehyde can be determined in the range 0.3–8.0 μg ml−1 (1.0×10−5–2.7× 10−4 M) with a sensitivity of 0.216 absorbance/ μg ml−1 (0.0065 absorbance/μM). Optimal conditions and the selectivity of this enzyme toward formaldehyde are described.
SOURCES OF THE ANTIBODIES DEVELOPING AFTER REPEATED TRANSFUSION.

The massive agglutination observable in the shed blood of transfused rabbits, and associated not infrequently with sudden marked blood destruction, has a practical significance in connection with the untoward results of repeated transfusion from donors originally compatible; and it has special theoretical interest because the clumping of the cells is apparently an autoagglutination. To determine the actual source of the antibodies has been the object of the present work. The agglutination in its most marked form has been traced to isoantibodies elicited by the presence in the body of corpuscles originally found compatible; and the frequently associated, rapid blood destruction is doubtless of similar origin. Occasionally antibodies develop in the donor bloods during the period of transfusion, but they are so weak as to be negligible. There remain instances of what would seem to be true autoagglutination due to serum bodies induced by the transfusions as a by-product, so to speak, in the manufacture of isoagglutinins. The antigenic relationship between the red cells of different rabbits is so close that normal isoagglutinins became fixed in the cold upon their elaborator's own corpuscles. Agglutinins exist within the red cells of rabbits—as has been claimed by Klein. They are readily demonstrable in watery extracts of the dried corpuscles. Whether similar agglutinins ever exist within human cells remains to be determined. We have not found them in the normal corpuscles.
Breadth or depth in introductory computer courses: The experimental results

These are the results of an experiment begun in 1978 to compare two sequences of introductory computer courses which differ by their approaches of breadth or depth. Statistical analysis of the results is presented which indicates the depth approach sometimes, but not always, has the advantage.
An Offline Map Matching via Integer Programming

The map matching problem is, given a spatial road network and a sequence of locations of an object moving on the network, to identify the path in the network that the moving object passed through. In this paper, an integer programming formulation for the offline map matching problem is presented. This is the first approach that gives the optimal solution with respect to a widely used objective function for map matching.
Study on Application of Embedded Real-Time Databases Technology in Dynamic Scheduling

Mass of real-time data needs to be handled in the environment of networked manufacturing; especially, the real-time requirement of MES oriented spot management is much higher. Moreover, embedded real-time databases technology is a software technology which lies between spot data and real-time operating system. And it conforms to the production requirement of networked manufacturing on the side of running environment and running mode. Simultaneously, it can reduce network load, and simply realize the communication among production equipments, MES system and upper management system with lower cost. In this paper, embedded realtime databases technology is applied to the design of MES dynamic scheduling. The attribute of real-time data is described from tense and time. According to the constrained relationship, the data attribute association classification is realized by using C++ language. The supporting level and confidence level are used to define the gauge of relevant regulation; According to the relevant regulation, the background database is built which is needed by the scheduling function of MES.net v1.0. As a result, the application of dynamic scheduling with real-time technology is realized.
Evaluation of oxygen extraction ratio as a physiologic transfusion trigger in coronary artery bypass graft surgery patients.

BACKGROUND: Approximately 20 percent of all allogeneic blood transfusions are administered in connection with coronary artery bypass graft (CABG) operations. Transfusion practices vary across the country. The whole-body oxygen extraction ratio (O 2 ER) reflects the adequacy of the patient's response to acute normovolemic anemia with an O 2 ER of approximately 50 percent being shown to be an appropriate transfusion trigger. The present study monitored the O 2 ER in patients undergoing CABG and determined if transfusion practices would have been different if an O 2 ER ≥45 percent were used as a transfusion trigger. STUDY DESIGN AND METHODS: Seventy patients with a postoperative Hct ≤25 percent were the test subjects. Arterial and mixed venous contents were determined before the operation, in the intensive care unit after the operation, and 12 hours after the operation. RESULTS: There were no deaths. Forty-one patients received allogeneic transfusion. These patients were older, weighed less, and had a preoperative Hct lower than the nontransfused patients. There were no significant differences between transfused and nontransfused patients with respect to postoperative Hct (21.0 ± 0.4 vs. 22.2 ± 0.4), cardiac index (2.5 ± 0.1 vs. 2.7 ± 0.1), O 2 delivery (6.4 ± 0.3 vs. 6.7 ± 0.3), O 2 consumption (2.5 ± 0.1 vs. 2.5 ± 0.1), and O 2 ER (38.3 ± 1.7 vs. 37.5 ± 1.5). In the transfusion group, 7 of 21 patients had a postoperative O 2 ER >45 percent, while 3 of 35 in the nontransfused group had that result. CONCLUSION: The use of O 2 ER as a transfusion trigger as part of a transfusion algorithm could lead to a reduction in allogeneic blood transfusion.
Possibility of reconciliation on the type of the order parameter in high-temperature superconductors

A model of high-{ital T}{sub {ital c}} superconductivity is proposed based on the following assumptions: (a) There are extended saddle-point singularities in the spectrum of electrons with a strongly enhanced density of states; (b) the interaction between electrons consists of a large and long-ranged phonon attraction and a small and short-ranged repulsion. It is shown that this model, having properties of both the {ital s}-wave and the {ital d}-wave approaches, can effectively explain most of the rather contradictory properties of these substances.
Structural diversity of gap junctions. A review.

Abstract Gap junctions are plasma membrane specializations characterized as aggregates of intramembranous particles in two apposed membranes meeting particle-to-particle in the 2–4 nm intermembrane ‘gap’. Recent thin-section and freeze-fracture evidence has revealed significant structural variations of gap junctional structure at various stages of development and from different organisms and tissues. It is suggested that a comparative analysis of these differences may provide clues to the specific biological function(s) of these ubiquitous organelles.
Correlation function studies for snow and ice

The random medium model is used to characterize snow and ice fields in the interpretation of active and passive microwave remote sensing data. A correlation function is used to describe the random permittivity fluctuations with the associated mean and variance and correlation lengths; and several samples are investigated to determine typical correlation functions for snow and ice. It is shown that correlation functions are extracted directly from appropriate ground truth data, and an exponential correlation function is observed for snow and ice with lengths corresponding to the actual size of ice particles or air bubbles. Thus, given that a medium has spatially stationary statistics and a small medium, the random medium model can interpret remote sensing data where theoretical parameters correspond to actual physical parameters of the terrain.
Molecular dynamics of mouse acetylcholinesterase complexed with huperzine A.

Two molecular dynamics simulations were performed for a modeled complex of mouse acetylcholinesterase liganded with huperzine A (HupA). Analysis of these simulations shows that HupA shifts in the active site toward Tyr 337 and Phe 338, and that several residues in the active site area reach out to make hydrogen bonds with the inhibitor. Rapid fluctuations of the gorge width are observed, ranging from widths that allow substrate access to the active site, to pinched structures that do not allow access of molecules as small as water. Additional openings or channels to the active site are found. One opening is formed in the side wall of the active site gorge by residues Val 73, Asp 74, Thr 83, Glu 84, and Asn 87. Another opening is formed at the base of the gorge by residues Trp 86, Val 132, Glu 202, Gly 448, and Ile 451. Both of these openings have been observed separately in the Torpedo californica form of the enzyme. These channels could allow transport of waters and ions to and from the bulk solution.
Ferromanganese nodules from MANOP Sites H, S, and R—Control of mineralogical and chemical composition by multiple accretionary processes

Abstract The chemical composition of ferromanganese nodules from the three nodule-bearing MANOP sites in the Pacific can be accounted for in a qualitative way by variable contributions of distinct accretionary processes. These accretionary modes are: 1. (1) hydrogenous, i.e., direct precipitation or accumulation of colloidal metal oxides in seawater, 2. (2) oxic diagenesis which refers to a variety of ferromanganese accretion processes occurring in oxic sediments; and 3. (3) suboxic diagenesis which results from reduction of Mn+4 by oxidation of organic matter in the sediments. Geochemical evidence suggests processes (1) and (2) occur at all three MANOP nodule-bearing sites, and process (3) occurs only at the hemipelagic site, H, which underlies the relatively productive waters of the eastern tropical Pacific. A normative model quantitatively accounts for the variability observed in nearly all elements. Zn and Na, however, are not well explained by the three end-member model, and we suggest that an additional accretionary process results in greater variability in the abundances of these elements. Variable contributions from the three accretionary processes result in distinct top-bottom compositional differences at the three sites. Nodule tops from H are enriched in Ni, Cu, and Zn, instead of the more typical enrichments of these elements in nodule bottoms. In addition, elemental correlations typical of most pelagic nodules are reversed at site H. The three accretionary processes result in distinct mineralogies. Hydrogenous precipitation produces δMnO2. Oxic diagenesis, however, produces Cu-Ni-rich todorokite, and suboxic diagenesis results in an unstable todorokite which transforms to a 7 A phase (“birnessite”) upon dehydration. The presence of Cu and Ni as charge-balancing cations influence the stability of the todorokite structure. In the bottoms of H nodules, which accrete dominantly by suboxic diagenesis, Na+ and possibly Mn+2 provide much of the charge balance for the todorokite structure. Limited growth rate data for H nodules suggest suboxic accretion is the fastest of the three processes, with rates at least 200 mm/106 yr. Oxic accretion is probably 10 times slower and hydrogenous 100 times slower. Since these rates predict more suboxic component in bulk nodules than is calculated by the normative analysis, we propose that suboxic accretion is a non-steady-state process. Variations in surface water productivity cause pulses of particulate flux to the sea floor which result in transient Mn reduction in the surface sediments and reprecipitation on nodule surfaces.
A finite model theorem for the propositional μ-calculus

We prove a finite model theorem and infinitary completeness result for the propositional μ-calculus. The construction establishes a link between finite model theorems for propositional program logics and the theory of well-quasi-orders.
Sarcoidosis, galactorrhea, and amenorrhea: 2 Autopsy cases, 1 with chiari‐frommel syndrome

Two women with amenorrhea and galactorrhea, 1 with Chiari-Frommel syndrome, died of cerebral sarcoidosis. At autopsy in both cases, sarcoid granulomas were numerous in the hypothalamus, but the pituitary appeared normal and did not contain increased prolactin as determined by immunoperoxidase technique. These are the first autopsy reports of sarcoidosis with galactorrhea and of Chiari-Frommel syndrome in the absence of pituitary adenoma.
Computer display of population age structure.

The standard human population pyramid contains only current information; it is often inadequate when making comparisons of different countries or years. A graphic computer program superimposes current population, life table survivor ships, stable population, and past population projected up to the present. Fertility, health conditions, migration, and demographic transition stage are better revealed by this expanded graph form. A time series of the modified pyramids reveals detailed age-specific trends for a country or region. With ’minor modifications the computer program is applicable to all machines with a Fortran IV compiler.
Changes in growth and virulence of a nuclear polyhedrosis virus from Choristoneura fumiferana after passage in Trichoplusia ni and Galleria mellonella

Abstract An isolate of nuclear polyhedrosis virus from Choristoneura fumiferana was fed to neonate larvae of Trichopulsia ni and Galleria mellonella. It caused infection and mortality in both of these species. After passage in the alternate hosts, the isolate became increasingly virulent for these hosts. The passaged virus retained its infectivity for Choristoneura but diseased larvae did not wilt and at death they were found to contain only a few polyhedra indicating the virus had been changed.
A cultural perspective on individual choices of STEM education and subsequent occupations

Attention to health and maintenance of a skilled IT workforce is an issue that will not disappear any time in the near future. There is also multi-disciplinary support for a new cultural approach to understanding student attraction to specific IT educational programs and the IT occupation. This paper proposes a new cultural framework to study influences on, and the specific nature of IT cultural assumptions and values of students that affect attraction to information technology (IT) related Science, Technology, Engineering, and Mathematics (STEM) education, and careers. We integrate two cultural theories specific to IT: Kaarst-Brown's (1995) theory of underlying assumptions that reflect one of five specific "IT Cultural Archetypes," and Guzman's (2006) theory of IT Occupational Culture and Commitment. This paper presents theoretical foundations, an investigative model with propositions, a discussion of methodological considerations, and implications for research.
Redirecting Our Voyage through History: A Content Analysis of Social Studies Textbooks.

At the heart of the debate over public school curriculum is the production of knowledge. The control of knowledge production is significant because it affects students' beliefs and attitudes about society. Because textbooks play such a crucial role in children's learning, multicultural education includes proposals for textbook changes to make the curriculum more representative of diverse views. This study examines the question: To what extent are social studies textbooks inclusive of diverse perspectives on U.S. history? In order to answer this question, we conducted a content analysis of the presentation of slavery in fifth-grade social studies texts being used in Connecticut. Our findings demonstrate that the majority of textbooks have reached the additive stage (including key themes and issues)for African American men and the contributions stage (including famous people and events) for African American and White women.
Surface Characterization by Reflection Electron Microscopy (REM)

Reflection electron microscopy (REM) utilizes the Bragg reflected high energy electrons to form the image of a crystal surface. Images of dislocations, atomic steps, reconstructions of surface layers of atoms and adatoms, stacking faults and twinning, superlattices, etc., have been successfully observed on a wide variety of specimens. Contrast is mainly due to diffraction and phase, which distiguished REM as a unique method for high spacial resolution and high sensitivity imaging of the surfaces of bulk specimens. REM can be effectively performed under UHV as well as under the moderate vacuum of an ordinary commercial electron microscope.
Application of a Diagnostic Richardson Number Tendency to a Case Study of Clear Air Turbulence

Abstract An index for the development of clear air turbulence on a synoptic scale is derived using the time rate of change of the Richardson number following the air motion, the so-called diagnostic Ri tendency. The method used in calculing the Ri tendency is a modified version of Roach's derivation, which in application had several undesirable features. The modification consisted in treating separately the effects of the change of stability and of the vertical wind shear, and expressing the change of the vertical wind shear by substitution from the thermal wind equation and then using the well-known frontogenetical function. The time rate of change of Ri was better expressed as the time to reduce Ri to the critical value, assumed to be unity since bulk layers were used. This index was tested on Hardy et al.'s case study of CAT observed at Wallops Island at 1700 GMT 19 February 1970 at the 750-mb level. Considering advection effects, it was found that the 800-mb level results presented have indicated that...
Biophysical Evidence of Arm–Domain Interactions in AraC

We report development of a method for the direct measurement of the interaction between the N-terminal arm and the remainder of the dimerization domain in the Escherichia coli AraC protein, the regulator of the l-arabinose operon. The interaction was measured using surface plasmon resonance to monitor the association between the immobilized peptide arm and the dimerization domain, truncated of its arm, in solution. As expected from genetic and physiological data, the interaction is strongly stimulated by l-arabinose and is insensitive to sugars like d-glucose or d-galactose. Alterations in the sequence of the arm which physiological experiments predict either to strengthen or weaken the arm produce the expected responses.
Towards a minimal motif for artificial transcriptional activators

Background: Most transcriptional activators minimally comprise two functional modules, one for DNA binding and the other for activation. Several activators also bear an oligomerization region and bind DNA as dimers or higher order oligomers. In a previous study we substituted these domains of a protein activator with synthetic counterparts [Mapp et al., Proc. Natl. Acad. Sci. USA 97 (2000) 3930–3935]. An artificial transcriptional activator, 4.2 kDa in size, comprised of a DNA binding hairpin polyamide tethered to a 20 residue activating peptide (AH) was shown to stimulate promoter specific transcription [Mapp et al., Proc. Natl. Acad. Sci. USA 97 (2000) 3930–3935]. The question arises as to the general nature and the versatility of this minimal activator motif and whether smaller ligands can be designed which maintain potent activation function. Results: Here we have replaced the 20 amino acid AH peptide with eight or 16 residues derived from the activation domain of the potent viral activator VP16. The 16 residue activation module coupled to the polyamide activated transcription over two-fold better than the analogous AH conjugate. Altering the site of attachment of the activation module on the polyamide allowed reduction of the intervening linker from 36 atoms to eight without significant diminution of the activation potential. In this study we also exchanged the polyamide to target a different sequence without compromising the activation function further demonstrating the generality of this design. Conclusions: The polyamide activator conjugates described here represent a class of DNA binding ligands which are tethered to a second functional moiety, viz. an activation domain, that recruits elements of the endogenous transcriptional machinery. Our results define the minimal structural elements required to construct artificial, small molecule activators. If such activators are cell-permeable and can be targeted to designated sites in the genome, this series of conjugates may then serve as a tool to study mechanistic aspects of transcriptional regulation and eventually to modulate gene expression relevant to human diseases.
The effect of height on family income.

The effect of height on earnings of adult males sampled in the second National Health and Nutrition Examination Survey, 1976-1980, was examined. Data were collected using the multistage probability sampling method. Information was available on medical history, physical examination, anthropometric dimensions, diet, and sociodemographic characteristics. Complete information was available on 4,563 males, aged 20-65 years. The correlation between family income and height was low (r = 0.13, P = 0.001). There was a secular trend for increasing mean height over time, so that younger individuals were taller than older ones even after correction for the decrease in stature caused by aging. After stratifying by age and race, education and marital status, but not height, were significantly associated with total family income. The weight-height ratio was significantly related to income of Whites but not of nonwhites. White males in the highest income category were significantly taller, heavier, more adipose, had higher levels of education, and were more often married than were their lowest income white counterparts. Among nonwhites, marital status and education alone differentiated highest from lowest income nonwhite males. Thus, at least for White males, appearance, that is, adiposity, together with education and marital status, are major factors relating to income.
Total Synthesis of Bryostatin 1

Bryostatin 1 is a marine natural product that is a very promising lead compound because of the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The synthetic route adopted is a highly convergent one in which the preformed, heavily functionalized pyran rings A and C are united by "pyran annulation", the TMSOTf-promoted reaction between a hydroxyallylsilane appended to the A-ring fragment and an aldehyde contained in the C-ring fragment, with concomitant formation of the B ring. Further elaborations of the resulting very highly functionalized intermediate include macrolactonization and selective cleavage of just one of five ester linkages present.
Cardiopulmonary bypass after cardiac arrest and prolonged closed-chest CPR in dogs.

We studied a clinically realistic field-to-hospital scenario in dogs with four-minute ventricular fibrillation (VF) cardiac arrest followed by 30-minute standard external CPR basic life support (BLS). At the end of this 34-minute insult, cardiopulmonary bypass (CPB) was used for early defibrillation and assisted circulation for one hour (n = 10). Recovery was compared with that of control dogs (n = 10) in which standard CPR with advanced life support (ALS) for another 30 minutes was used for restoration of spontaneous circulation (ROSC). Both groups had hemodilution and heparinization, controlled blood pressure, blood gases, ventilation, and other parameters for 20 hours; and intensive care to 72 hours. During CPR-BLS of 30 minutes in both groups signs of cerebral viability returned. CPB achieved ROSC more successfully (ten of ten vs five of ten CPR-ALS controls) ( P P P P = .025). Starting CPR-BLS within four minutes of arrest can maintain cerebral viability. CPB increases cardiovascular resuscitability and thereby survival without neurologic deficit as compared to CPR-ALS.
Robot-assisted Transrectal Hybrid Natural Orifice Translumenal Endoscopic Surgery Nephrectomy and Adrenalectomy: Initial Investigation in a Cadaver Model

Objective To assess the feasibility of robotic transrectal hybrid natural orifice translumenal endoscopic surgery (NOTES) nephrectomy and adrenalectomy. Materials and Methods A male cadaver was used for the present investigation and placed in lithotomy position. An 8- and 12-mm port was inserted through the same periumbilical skin incision. An incision was then created in the rectum 1 cm above the pectinate line, and a submucosal tunnel was developed, through which a robotic 8-mm port was inserted under vision. The cadaver was then placed in the right side up, flank position. The laparoscope and the right robot instrument were introduced through the umbilicus while the left robot instrument was introduced through the rectal port aiding the peri-umbilical ports in kidney and adrenal dissection. After completion of the nephrectomy, the kidney was placed in a specimen bag and extracted intact through the rectum. Closure of the rectal incision was accomplished extracorporeally using 2 suture layers. Results Robotic transrectal hybrid NOTES nephrectomy and adrenalectomy were completed successfully. The total operative time was 145 minutes, of which the access and robotic docking required 20 minutes. Kidney dissection and hilar control was achieved within 60 minutes. Right adrenalectomy, specimen extraction, and rectal closure was completed in 15, 30, and 20 minutes, respectively. Conclusion We report the first investigation of a robot-assisted transrectal hybrid NOTES nephrectomy and adrenalectomy in a cadaver model to assess the range of motion and articulation of the robotic platform. Additional investigations in live animal model are needed to evaluate the safety of the transrectal approach.
Effects of Treatment on the Work Experiences of Long-Term Survivors of Hodgkin's Disease

The work experiences of 85 men who were long-term survivors of Hodgkin's disease were compared with the experiences of a similar group of 88 survivors of testicular cancer. The results suggested that survivors of Hodgkin's disease had more difficulties in completing work tasks. The focus of the remaining analyses was to explain the poorer work experiences of survivors of Hodgkin's disease using a measure of physical performance at work and at leisure adapted from studies on biological energy. The results indicating that treatment for Hodgkin's disease has measurable effects on performance of leisure activities but not on work activities are consistent with this earlier work. Changes in leisure activity also had a negative effect on the men's mood state. The findings are discussed in relation to policy issues of concern to those involved in the rehabilitation of canccr survivors.
Production of infectious virus and degradation of APOBEC3G are separable functional properties of human immunodeficiency virus type 1 Vif

HIV-1 Vif regulates viral infectivity by inhibiting the encapsidation of APOBEC3G (APO3G) through proteasomal degradation of the protein. Here we compared various Vif proteins for their ability to induce APO3G degradation and rescue viral infectivity. We found that Vif expressed from proviral vectors caused relatively inefficient degradation of APO3G in HeLa cells yet was very effective in inhibiting APO3G's antiviral activity. On the other hand, Vif expressed autonomously from a codon-optimized vector caused very efficient APO3G degradation and also effectively inhibited APO3G's antiviral effects. In contrast, a Vif chimera containing an N-terminal fluorescent tag efficiently induced APO3G degradation but was unable to restore viral infectivity. The lack of a direct correlation between APO3G degradation and rescue of viral infectivity suggests that these two properties of Vif are functionally separable. Our data imply that intracellular degradation of APO3G may not be the sole activity of Vif required for the production of infectious virions from APO3G-expressing cells.
Undocumented immigration and the business of farm labor contracting in the USA

Purpose – Farm labor contractors operate as intermediaries between farmworkers and agricultural employers by recruiting and supplying labor to US farms. In a political economy where there are employer sanctions for hiring workers without proper documentation, contractors share risk alongside final employers. Furthermore, contractors may facilitate quick employment matches during time sensitive agricultural tasks such as harvesting. For undocumented workers, using a contractor may decrease uncertainty associated with a foreign labor market and ease language barriers. The purpose of this paper is to examine the current role of labor contractors in delivering immigrant agricultural workers, particularly undocumented workers, to farms.Design/methodology/approach – Determinants of labor contractor use and relationships to final worker outcomes are examined using econometric methods and a large nationally‐representative worker survey that is distinctive in that it distinguishes legal status.Findings – Undocumen...
Ligand Concentration Regulates the Pathways of Coupled Protein Folding and Binding

Coupled ligand binding and conformational change plays a central role in biological regulation. Ligands often regulate protein function by modulating conformational dynamics, yet the order in which binding and conformational change occurs are often hotly debated. Here we show that the "conformational selection versus induced fit" distinction on which this debate is based is a false dichotomy because the mechanism depends on ligand concentration. Using the binding of pyrophosphate (PPi) to Bacillus subtilis RNase P protein as a model, we show that coupled reactions are best understood as a change in flux between competing pathways with distinct orders of binding and conformational change. The degree of partitioning through each pathway depends strongly on PPi concentration, with ligand binding redistributing the conformational ensemble toward the folded state by both increasing folding rates and decreasing unfolding rates. These results indicate that ligand binding induces marked and varied changes in protein conformational dynamics, and that the order of binding and conformational change is ligand concentration dependent.
Regulation of protein secretion by ... protein secretion

Mycobacterium tuberculosis (Mtb) requires an alternative protein secretion system, ESX1, for virulence. Recently, Raghavan et al. (2008) reported a new regulatory circuit that may explain how ESX1 activity is controlled during infection. Mtb appears to regulate ESX1 by modulating transcription of associated genes rather than structural components of the secretion system itself.
Menadione Requirements of Chickens Selected for Prothrombin Time

Abstract DIFFERENCES in blood coagulation and prothrombin times were observed between lines of chickens by Mohapatra et al. (1967), Charles et al. (1967) and Mohapatra and Siegel (1969a). A genetic basis for such differences was shown by Mohapatra and Siegel (1969b) who developed, through mass selection, lines for fast and slow blood prothrombin times. The experiment reported here was conducted to determine if the changes in prothrombin times were associated with vitamin K requirements. Presented are data from three experiments designed to determine the vitamin K3 (menadione) requirements of the fast prothrombin (FPL) and slow prothrombin (SPL) lines. METHODS AND MATERIALS Chicks obtained from F4 generation matings of the FPL and SPL lines were fed varying levels of vitamin K3. The only dietary source of vitamin K was from pure menadione that was added to the semipurified diet described in Table 1. The levels of vitamin K3 added to the basal…
Changes in purine nucleoside phosphorylase activity during thymosin-induced human null cell differentiation

Purine nucleoside phosphorylase (PNP) is a purine salvage pathway enzyme which we have found to be 8-10 times more active (per cell) in human peripheral blood null lymphocytes than in T lymphocytes. To test the hypothesis that null cells are, in part, pre-T lymphocytes we have defined an in vitro system for null cell differentiation into T cells and examined PNP activity during this differentiation process. We found that about 10% of human null cells could be driven to differentiate into T cells using thymosin fraction 5 (TF5) an extract of bovine thymus glands. The response to TF5 was dose related to up to 250 micrograms/ml with a maximum response occurring by 42-46 hr incubation. Exposure to TF5 was necessary for more than 4 hr but no more than 8 hr in order to obtain a maximum response. Both OKT4 and OKT8 positive cells were present in the newly differentiated T cell population but OKT8 positive cells appeared to predominate (OKT4/OKT8 = 0.698 +/- 0.30, mean +/- 1 SD). The differentiation process did not involve DNA synthesis but was inhibited at 4 degrees C. In the newly differentiated T cells PNP activity per cell was 8- to 10-fold lower (36 +/- 23 nm/hr/106 cells) than in null cells (311 +/- 136), and was at a level similar to mature T cells (56 +/- 7). Thus, human peripheral blood null cells can be induced to differentiate into T lymphocytes which can be characterized by both surface markers and biochemical parameters. Future studies will look at the function of TF5-induced T cells and the regulation of PNP activity during the differentiation process.