cssi/SciSciGPT-SciSciNet huggingface dataset:
Removing the sampling restrictions from family-based tests of association for a quantitative-trait locus.

Summary One strategy for localization of a quantitative-trait locus (QTL) is to test whether the distribution of a quantitative trait depends on the number of copies of a specific genetic-marker allele that an individual possesses. This approach tests for association between alleles at the marker and the QTL, and it assumes that association is a consequence of the marker being physically close to the QTL. However, problems can occur when data are not from a homogeneous population, since associations can arise irrespective of a genetic marker being in physical proximity to the QTL—that is, no information is gained regarding localization. Methods to address this problem have recently been proposed. These proposed methods use family data for indirect stratification of a population, thereby removing the effect of associations that are due to unknown population substructure. They are, however, restricted in terms of the number of children per family that can be used in the analysis. Here we introduce tests that can be used on family data with parent and child genotypes, with child genotypes only, or with a combination of these types of families, without size restrictions. Furthermore, equations that allow one to determine the sample size needed to achieve desired power are derived. By means of simulation, we demonstrate that the existing tests have an elevated false-positive rate when the size restrictions are not followed and that a good deal of information is lost as a result of adherence to the size restrictions. Finally, we introduce permutation procedures that are recommended for small samples but that can also be used for extensions of the tests to multiallelic markers and to the simultaneous use of more than one marker.
Isolation and characterization of thymidylate synthetase mutants of Xanthomonas maltophilia.

Thymidylate synthetase mutants of Xanthomonas maltophilia ATCC 13270 were isolated on a solid minimal medium containing 50 mg/l thymidine and a high concentration of trimethoprim (500 mg/l). It was found that a high concentration of trimethoprim was required to prevent background growth of the wild-type strain. The isolated mutants could grow on thymidine or dTMP at a concentration of 50 mg/l while they were unable to grow on 1000 mg/l thymine or 50 mg/l deoxyridine. Thymidylate synthetase activity was assayed in the wild-type cells and in the mutant cells but only the wild-type cells contained measurable enzyme activity.
Predictors of the transition to regular smoking during adolescence and young adulthood

Abstract Purpose To identify predictors of the transition from experimentation to regular smoking in middle adolescence, late adolescence, and young adulthood. Methods California and Oregon students completed self-report surveys assessing the following potential predictors of the transition to regular smoking from grades 8 to 10 (n = 2496), grades 10 to 12 (n = 2149), and grade 12 to age 23 years (n = 1534): demographic characteristics; smoking-related attitudes, behaviors and environment; other problem behaviors; academic orientation; parental bonding; and mental health. Huberized regression techniques, which adjust for weighting and clustering of observations, were used to determine the independent associations of the predictor variables on subsequent smoking status. Results Risk factors for the transition to regular smoking during middle adolescence included being white, prosmoking attitudes, friend smoking, weak academic orientation, and less parental support. During late adolescence, being African-American was protective, whereas risk factors included prosmoking attitudes, drinking, non-intact nuclear family, and less parental support. Risk factors in young adulthood included younger age and prosmoking attitudes. Conclusions Results point to several smoking-related attitudes, social influences, and behaviors that prevention efforts may target to curb the escalation of smoking.
Online Reporting of Results for Online Student Ratings.

In this chapter, the author examines important issues related to online reporting of student survey results.
Contact microradiography in the study of alloys

Abstract Microradiography is a long-established technique for viewing the internal structure of opaque materials. An image is obtained by placing a thin specimen in contact with a fine-grained photographic emulsion and exposing it to radiation from an industrial-type x-ray tube. The primary image (radiograph) represents a variation in intensity of the transmitted beam owing to differential absorption by the various phases in the material. The microradiograph is obtained by enlarging the primary image by means of the light microscope. A general review of the technique, including specific applications, is presented in this report. Image resolutions up to the resolving power of the light microscope have been achieved with one metallurgical specimen in particular.
Human immunodeficiency virus type 1 compartmentalization in the central nervous system

HIV-1 replicates in monocyte-derived cells in multiple organ systems; in the central nervous system, productive infection is confined to monocyte lineage cells in the brain. In addition, productive viral infection takes place in the choroid plexus, where the incidence of infection is actually higher than in brain and is present prior to the onset of AIDS and immunosuppression. Restricted or latent infection occurs in astrocytes and neurons. The presence of perineuronal CD4+ lymphocytes, as well as activated microglia, support the potential for a trans-receptor mechanism of viral entry whereas intrinsic gene profiles do not appear to participate in conferring selective neuronal vulnerability or resistance to infection.
The role of upstream sequences in selecting the reading frame on tmRNA

Background: tmRNA acts first as a tRNA and then as an mRNA to rescue stalled ribosomes in eubacteria. Two unanswered questions about tmRNA function remain: how does tmRNA, lacking an anticodon, bypass the decoding machinery and enter the ribosome? Secondly, how does the ribosome choose the proper codon to resume translation on tmRNA? According to the -1 triplet hypothesis, the answer to both questions lies in the unique properties of the three nucleotides upstream of the first tmRNA codon. These nucleotides assume an A-form conformation that mimics the codon-anticodon interaction, leading to recognition by the decoding center and choice of the reading frame. The -1 triplet hypothesis is important because it is the most credible model in which direct binding and recognition by the ribosome sets the reading frame on tmRNA. Results: Conformational analysis predicts that 18 triplets cannot form the correct structure to function as the -1 triplet of tmRNA. We tested the tmRNA activity of all possible -1 triplet mutants using a genetic assay in Escherichia coli. While many mutants displayed reduced activity, our findings do not match the predictions of this model. Additional mutagenesis identified sequences further upstream that are required for tmRNA function. An immunoblot assay for translation of the tmRNA tag revealed that certain mutations in U85, A86, and the -1 triplet sequence result in improper selection of the first codon and translation in the wrong frame (-1 or +1) in vivo. Conclusion: Our findings disprove the -1 triplet hypothesis. The -1 triplet is not required for accommodation of tmRNA into the ribosome, although it plays a minor role in frame selection. Our results strongly disfavor direct ribosomal recognition of the upstream sequence, instead supporting a model in which the binding of a separate ligand to A86 is primarily responsible for frame selection.
Terrorism and democratic states: Soft targets or accessible systems

This study evaluates the relationship between democracy and the decision calculus of terrorist organizations. Starting with a simple formalization of the budget constraint for terrorist organizations, this project evaluates two schools of thought regarding the role of democracy. The first school, labeled the strategic school, argues that democratic regimes decrease the price of violence and therefore encourage terrorism. The second school, labeled the political access school, argues that democratic regimes decrease the price of non‐violent political expression and thereby decrease the probability of terrorism. These competing explanations are evaluated against the ITERATE cross‐national time series data for the years 1968 to 1986, using a negative binomial regression event count model. The results show that established democracies are less likely to experience terrorism than non‐democracies, but that newly formed democracies are more likely to experience terrorism than other types of states.
Task experience and attitudes towards decision making

Abstract This study attempts to extend the work by Breer and Locke (1965) on the effect of task experience on the development of attitudes. Subjects were assigned either to a task where rational problem solving approaches were instrumental to task success, or where rational approaches were less instrumental. The hypothesis that different task experience (rational vs. irrational) would lead to differential attitude change received some support. The relationship between this experiment and the work of Breer and Locke, and of the relationship between task experience and other attitude-change theories, were discussed.
The Imprint of Intrathymic Self-Peptides on the Mature T Cell Receptor Repertoire

Abstract The analysis of T cell receptor α (TCRα) chains in mice transgenic for a TCRβ chain has allowed us to demonstrate a central role for self-peptides in the positive intrathymic selection of major histocompatibility complex (MHC) class II–restricted T cells. Analysis of specific Vα–Jα joins in mature CD4 + TCR high thymocytes and in peripheral CD4 + T cells revealed a limitation in amino-acid sequences. By analysis of immature thymocytes, we could show that this limited repertoire was selected from a more diverse repertoire. By analysis of the same β chain–transgenic mice bred to H-2Ma-deficient mice that express one or a very limited number of peptides, we could demonstrate that the Vα–Jα join repertoire was now altered and much more limited. Together, these data provide molecular and genetic evidence that the intrathymic positive selection of the TCR repertoire is critically affected by self-peptides presented by MHC class II molecules, most likely on thymic cortical epithelial cells.
Bacterial adherence on replicas of sodium dodecyl sulfate-polyacrylamide gels.

A method for determining which molecules in a complex mixture of proteins can function as bacterial receptors was devised. Salivary proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose. Bacteria that were metabolically labeled with 3H or externally labeled with 125I were incubated on the nitrocellulose replicas. After 18 h at 4°C, the unbound cells were removed by repeated washing of the replicas, and the bands to which the radiolabeled bacteria bound were visualized by autoradiography. By this technique, Fusobacterium nucleatum, which adheres via carbohydrate residues on receptor molecules, and Staphylococcus aureus, which recognizes the peptide portion of fibronectin, were shown to bind specifically to their respective receptors. These results suggest that this method can be useful for profiling bacterial binding to either the carbohydrate or the protein portions of molecules present in complex mixtures, such as those composing biological fluids or tissue substrates. Structural specificities, such as recognition sequences formed by certain oligosaccharides, could be further investigated by adding the appropriate simple sugers, as well as oligosaccharide inhibitors, to the incubation medium. The latter approach is particularly important since most glycoproteins carry multiple N- and O-linked carbohydrate substituents that could serve as bacterial receptors.
Depression of phagocytosis in Mercenaria following chemical stress.

Abstract A chemical (phenol) stressor induces changes in phagocytic ability in the hard clam, Mercenaria mercenaria ; cytoplasmic disorganization and selective lysis of hemocytes are observed. In invertebrates, infectious agents are primarily controlled by nonspecific cellular defense mechanisms and stressors may alter the host-parasite complex with pathological consequences.
Arm exercise testing predicts clinical outcome

Background Treadmill exercise testing provides prognostic and clinical information that is not available for patients with lower extremity disabilities who undergo pharmacologic stress tests. We sought to determine whether arm ergometer (AXT) exercise capacity in resting metabolic equivalents (METs) and hemodynamic and electrocardiographic responses to AXT are predictors of survival, myocardial infarction (MI), or coronary revascularization, individually or as a composite. Methods A prospective cohort of 359 veterans aged 63 ± 11 (SD) years, who were unable or unwilling to perform treadmill exercise, underwent AXT stress testing for clinical reasons between 1997 and 2002 and were followed for 63 ± 24 months to an end point of death or December 31, 2006. Average annual mortality, MI, revascularization, and combined event rates were 5.2%, 1.7%, 2.2%, and 7.1%, respectively. Results By univariate analysis, AXT METs were highly predictive of survival ( P P P P = .058). By Wald χ 2 analysis, age, clinical variables, exercise capacity in METs, a positive exercise electrocardiogram, and delta heart rate all had statistically significant incremental prognostic value ( P Conclusion In older veterans with lower extremity disabilities and more comorbidities than most study populations, arm exercise capacity, delta heart rate, and a positive electrocardiogram were independently predictive of survival and/or adverse cardiovascular outcomes.
Application of hydrophobic interaction displacement chromatography for an industrial protein purification.

Recently it has been established that low molecular weight displacers can be successfully employed for the purification of proteins in hydrophobic interaction chromatography (HIC) systems. This work investigates the utility of this technique for the purification of an industrial protein mixture. The study involved the separation of a mixture of three protein forms, that differed in the C-terminus, from their aggregate impurities while maintaining the same relative ratio of the three protein forms as in the feed. A batch high-throughput screening (HTS) technique was employed in concert with fluorescence spectroscopy for displacer screening in these HIC systems. This methodology was demonstrated to be an effective tool for identifying lead displacer candidates for a particular protein/stationary-phase system. In addition, these results indicate that surfactants can be employed at concentrations above their CMCs as effective displacers. Displacement of the recombinant proteins with PEG-3400 and the surfactant Big Chap was shown to increase the productivity as compared to the existing step-gradient elution process.
Looking forward and back: Sexual victimization prevention

The field of sexual victimization prevention has been greatly shaped by societal movements of the past forty years. The social forces that have driven the study of sexual victimization have led to major research gaps which may be viewed as opportunities for new focuses. This paper will: (1) review these social movements in light of the opportunities that have arisen, (2) re-evaluate the information that has been collected in light of the research purpose, preventing harm to potential victims through providing tailored prevention messages, victim sensitive avenues of reporting, and individualized intervention tactics based on personality characteristics, and (3) provide a framework with which to conceptualize normative personality in relation to the process of victimization-related trauma. Although research has provided many insights into the basic principles of prevention, much remains to be explored.
Comparative habitat associations in juvenile Pacific cod and other gadids using seines, baited cameras and laboratory techniques

Abstract Pacific cod are commercially and ecologically important in the North Pacific, currently ranking 2nd in tonnage and value landed in the Alaskan groundfish fishery. To date, few studies have focused on the habitat requirements of Pacific cod, and as a result, our understanding of their ecology has largely been borrowed from better-studied gadid species, especially Atlantic cod. In July–Aug 2006, we used field and laboratory techniques to explicitly examine habitat associations of Pacific cod and two co-occurring gadids, saffron cod (Eleginus gracilis) and walleye pollock (Theragra chalcogramma), in coastal areas around Kodiak Island, AK. Pacific cod were the most abundant gadid in seine collections, followed by saffron cod and walleye pollock respectively. Small Pacific cod (3.5–7.5 cm TL) were most highly associated with Laminaria and eelgrass beds but moved into open habitats at larger sizes i.e., > 8.0 cm TL. Baited cameras indicated that the majority of juvenile Pacific cod were nearshore in August (i.e., ≤ 4.5 m), but schools were also seen in deeper (6.0–13.5 m), unstructured habitats. In contrast, age-0 saffron cod were almost exclusively restricted to eelgrass beds (Zostera marina) (3.5–13.0 cm) as were later year-classes i.e., 18–50 cm. Pollock were highly variable in their distribution, and were almost absent from the nearshore in late August. In 2 m experimental aquaria, Pacific and saffron cod chose macrophyte habitats under increased predation risk but also associated with these habitats at larger scales (i.e., c. 10 m tank) in the absence of a predator. Our results indicate both distinct differences and parallels between Pacific and Atlantic cod that will guide future process-oriented habitat research in both species.
The Relationship between Latino Students' Learning Styles and Their Academic Performance.

The purpose of this study was to explore the relationship between Latino Students' learning styles and their academic performance. Students' academic performance was measured using their overall grade point average (GPA). A group of 229 Latino students who were enrolled at an urban community college in New York City participated in the study. Two questionnaires were used to identify Students' learning styles; the Learning Style Inventory (LSI) developed by Kolb (2000), and the Productivity Environmental Preference Survey (PEPS) developed by Dunn, Dunn, and Price (2003). The results of the LSI showed no relationship between Students' learning styles and their GPA. Results of the PEPS showed a relationship between four of the PEPS' elements and the Students' GPA. The elements of Responsible (r = .174, p = .015) and Design (r = .162, p = .009) positively correlated with participants' GPA. Conversely, the elements of Needs Mobility (r = −.137, p = .008) and Afternoon (r = −.175, p = .039) negatively correlate...
Effect of Hypothermia, Dichloroacetate, and Deferoxamine in the Treatment for Cortical Edema and Functional Recovery after Experimental Cortical Impact in the Rat

Objective: To investigate the effects of hypothermia alone or in combination with dichloroacetic acid (DCA) and/or deferoxamine (DFO) in reducing cortical edema (CE) and improving neurologic functional recovery after moderate closed head trauma with controlled cortical impact (CCI). Methods: Anesthetized rats were randomized to receive right parietal moderate CCI (impact depth 2 mm, speed 3.5 m/sec) or sham operations. Immediately after trauma, the animals underwent selective brain cooling to 30°C (temporalis muscle temperatures). Ten minutes after trauma, the randomized animals received intra-peritoneal doses of DCA (25 mg/kg), DFO (50 mg/kg), both DCA and DFO, or equivolume normal saline. For evaluation of cortical edema, some animals (n = 42) were sacrificed 4 hours after trauma and cortical specific gravity (SpG) was determined gravimetrically. The other animals (n = 47) were evaluated for functional recovery beginning 6 days posttrauma. Neurobehavioral performance was assessed in the Morris water maze. Results: Cortical edema was significantly less in the animals treated with hypothermia (SpG = 1.041 ± 0.001, p < 0.05) compared with the untreated traumatized animals (SpG = 1.037 ± 0.001). Combination treatment with hypothermia and drug treatment did not reduce cortical edema when compared with no treatment. Hypothermia with and without drug treatment did not improve neurobehavioral performance when compared with no treatment. Conclusions: In this pilot study with a relatively small sample size, hypothermia alone significantly reduced post-CCI cortical edema as measured by SpG. Hypothermia combined with drug treatment did not reduce posttraumatic cortical edema. Hypothermia with and without drug therapy did not improve functional neurologic recovery in the rats subjected to CCI.
Laboratory Rat Experiments Show Consumption of Lake Ontario Salmon Causes Behavioral Changes: Support for Wildlife and Human Research Results

As part of the Cause-Effect Linkages II Conference, research was reviewed that showed behavioral changes in laboratory rats fed for 20 days a 30% diet of Lake Ontario salmon. Results from nine behavioral tests indicate that when testing involved a negative experience rather than only a positive experience the experimental group fed Lake Ontario salmon differed from the control groups fed Pacific Ocean salmon or no salmon. Behavioral differences between the two control groups have never been found. Offspring of rats fed the Lake Ontario salmon diet showed similar behavioral changes, even when tested in adulthood and never fed Lake Ontario salmon. These results, using the experimental method, can be viewed as providing the “missing link” between the results observed in wildlife living in the Great Lakes region and children whose mothers had eaten Lake Michigan fish (see other papers in this journal issue). Since the adult rats fed Lake Ontario salmon and their offspring showed no signs of illness and had equal weight gain when compared with the two control groups, it appears as if changes in behavior may occur at doses lower than those needed to produce physical illness.
Dynamics of the non-autonomous stochastic p-Laplace equation driven by multiplicative noise

We investigate the asymptotic behavior of solutions of the p-Laplace equation driven simultaneously by non-autonomous deterministic forcing and multiplicative white noise on R n . We show the tails of solutions of the equation are uniformly small outside a bounded domain, which is used to derive asymptotic compactness of solution operators in L 2 ( R n ) by overcoming the non-compactness of Sobolev embeddings on unbounded domains. We then prove existence and uniqueness of random attractors and further establish upper semicontinuity of attractors as the intensity of noise approaches zero.
"Functional" defective articulation: an oral sensory disturbance.

Some sources of disordered articulation may be related to oral sensory disabilities alone. One method of evaluating oral sensory functioning is to test for lingual stereognostic capability. Two groups, aged 12 to 16, of 10 children considered to be normal speakers (Group A) and 10 children considered to have “functional” articulation (Group B) as judged by a speech pathologist were free of sensory and motor defects. 20 geometric plastic forms, developed by the National Institute of Dental Research (NIDRs 20) were used to assess perceptual discrimination: eye, finger tip, tongue tip, and tongue blade. In general, larger mean differences were found between the normal and “functional” articulation groups than within them. The groups differed consistently in the general performance levels on the oral stereognostic tasks and in the oral-tactile performance not only within groups but between groups. Ss with “functional” articulation disorders (Group B) made more and different types of errors than normal speaker...
Applications of intravascular scanning and transesophageal echocardiography in congenital heart disease: tradeoffs and the merging of technologies

This chapter will review the evolving role of intravascular ultrasound imaging and transesophageal echo in the care of children, infants and adults with congenital heart disease. The technologies relevant to congenital heart disease applications differ from those involving coronary disease since the intravascular structures imaged often involve visualization of large vessels and cardiac chambers. On the other hand, the requirements for transesophageal echo in children with congenital heart disease involve intraoperative (surgical) and imaging procedures in the catheterization laboratory which are performed for monitoring interventional catheterization therapy. As such, whereas the intravascular devices needed for pediatric cases involve lower frequency and sometimes larger catheters, the requirements for transesophageal echocardiography require higher frequency and smaller esophagoscopes. Applications of intravascular imaging including sizing of congenital stenoses, dilation of coarctation and valvular stenoses, imaging of intrapulmonary thrombi and monitoring of placement of ASD ‘button’ devices in the heart will be reviewed. The intraoperative transesophageal uses for monitoring infant surgery include procedures for tetralogy repair, transposition repair and repair of AV septal defects and other complex congenital heart disorders. Both of these ‘invasive’ methods of echocardiography have an important and evolving role in the management of congenital heart disease in children and infants.
Inducibility of transferrin receptors on friend erythroleukemic cells

The ability of Friend erythroleukemic cells to bind transferrin and take up its iron increases substantially as a result of dimethyl sulfoxide-stimulated differentiation. Although transferrin-binding activity is also demonstrable in another mouse cell line of hematopoietic origin, the lymphoma cell, it does not increase on exposure to dimethyl sulfoxide. Gel filtration studies corroborate that the binding of transferrin to the erythroleukemic cells is due to the formation of a specific complex of transferrin and a membrane receptor. Thus, the specific interaction of transferrin with its receptor is another expression of dimethyl sulfoxide-induced differentiation in the Friend cell.
Impact of Obesity and Physical Activity on Functional Outcomes in the Elderly: Data From NHANES 2005-2010

Objective: The objective of this study was to (a) to examine whether the association between obesity and physical functioning among older adults is moderated by physical activity (PA) and (b) to te...
Melatonin enhances horizontal cell sensitivity in salamander retina.

Abstract Intracellular electrophysiological recording techniques were utilized to investigate the possible function of retinal melatonin in the larval tiger salamander. Endogenous retinal melatonin was present and appeared to bind to a membrane-enriched fraction of the salamander retina, as determined by radioimmunoassay and receptor binding studies. Melatonin added through the purfusion bath to flat-mounted retinas resulted in a horizontal cell(HC) hyperpolarization of 10–20 mV. Additionally, the amplitude of HC responses to short test flashes increased in the presence of melatonin. Voltage-intensity plots revealed that application of 500 μM of melatonin caused an increase of the HC light sensitivity and this effect was reversible. These results suggest that melatonin synthesized and released during the dark period of the diurnal cycle may alter the sensitivity of second-order neurons at a time of day when photopic input is at its lowest level.
A Snapshot Algorithm for Linear Feedback Flow Control Design

The control of fluid flows has many applications. For micro air vehicles, integrated flow control designs could enhance flight stability by mitigating the effect of destabilizing air flows in their low Reynolds number regimes. However, computing model based feedback control designs can be challenging due to high dimensional discretized flow models. In this work, we investigate the use of a snapshot algorithm proposed in Ref. 1 to approximate the feedback gain operator for a linear incompressible unsteady flow problem on a bounded domain. The main component of the algorithm is obtaining solution snapshots of certain linear flow problems. Numerical results for the example flow problem show convergence of the feedback gains.
Fluorine-substituted tetraazaannulene complexes: syntheses and characterizations

Abstract The syntheses of two new fluorine-substituted tetraazaannulene macrocyclic complexes have been accomplished. A mixture of the cis - and trans -bis(trifluoromethyl) substituted macrocycles, 5,7-bis(trifluoromethyl)-12,14-dimethyldibenzo[ b , i ][1,4,8,11]- tetraaza[14]annulene nickelate, [Ni( cis -BTDMTAA)], and 5,12-bis(trifluoromethyl)-7,14-dimethyldibenzo[ b , i ][1,4,8,11]-tetraaza[14]annulene nickelate, [Ni( trans -BTDMTAA)], results in low yield from the reaction of 1,1,1-trifluoro-2,4-pentanedione and 1,2-diaminobenzene in the presence of nickel(II) acetate tetrahydrate. The two one-electron oxidations observed for the corresponding Ni(II) complex of the tetramethyltetraazaannulene are shifted to significantly more positive values (+0.85 and + 1.15 V). The macrocyclic complexes do not display the characteristic electropolymerization of other tetraazaannulenes, which suggests that the second oxidation is not associated with the oxidation of a coupled dimer. The bis(trifluoromethyl) derivatives do bind CO 2 in solution and catalyze the electrochemical reduction to formate. The reduction occurs at −1.06 V, almost 0.5 V more positive than the value observed for the electropolymerized tetramethyl complex. An octafluorotetramethyltetraazaannulene, prepared by the reaction of 3,4,5,6-tetrafluoro-l,2-diaminobenzene with 2,4-pentanedione, is also reported.
P-FIT: A major contribution to theories of intelligence

The P-FIT model is a major step forward in understanding biological causes of intelligence. It is consistent with evidence on the influence of working memory and speediness upon intelligence, and with models that emphasize the role of interaction between modules to produce intelligence. The contribution to understanding genetic contributions is problematical, due to the difficulty of isolating the genes involved.
Dissolved Inorganic Carbon in the Tucson Basin Aquifer

The concentration of dissolved inorganic carbon (DIC) species and the other major ionic constituents were determined at 45 sampling locations within the Tucson basin aquifer. The distribution and concentration of the various inorganic carbon species were related to the hydrogeological characteristics of the principal recharge zones within this alluvial basin. Bicarbonate alkalinity concentrations were highest subjacent to a floodplain where calcite and other relict salts likely precipitated in the shallow subsurface under past pluvial conditions. Calculated partial pressure of carbon dioxide (PCO2) values were highest where the water table is sufficiently elevated to support phreatophyte growth. The regional distribution of PCO2 suggests that the generation of carbon dioxide is limited to the oxidation of influent plant detritus below the stream channels. The alkalinization of Tucson basin ground water is ultimately constrained by this limited production of CO2. The dissolution of calcite in young ground water (<200 years) and the precipitation of calcite in deeper, more chemically evolved ground water likely represent other important controls upon DIC concentrations.
Electron microscopy and image processing applied to the study of protein structure and protein-protein interactions.

We review the application of electron microscopy and image processing at the molecular level to an ever increasing range of biological specimens. Although recent advances have been due in part to development of more sophisticated instrumentation and/or processing algorithms, widespread application of the well-known techniques of image enhancement and structure reconstruction has depended on new strategies of in vitro crystallization and polymerization, some of which are outlined here. We also discuss the use of stoichiometric labeling and/or “cocrystallization” in identifying the different subunits in multisubunit complexes and in studying protein—protein interactions.
Positron‐Emission Tomography for Surveillance of Head and Neck Cancer

Objectives/Hypothesis: To determine the diagnostic accuracy and the ideal timing of 18fluoro-fluorodeoxyglucose positron-emission tomography (PET) in the posttreatment surveillance of head and neck mucosal squamous cell carcinoma (HNSCC). Study Design: Retrospective chart review. Methods: Our sample includes 103 adult patients with 118 posttreatment PET scans who had undergone treatment for HNSCC. We correlated PET results with surgical pathology and clinical outcome in the subsequent 6 months. Results: For the detection of locoregional persistent or recurrent HNSCC, PET scans had a sensitivity of 82%, specificity of 92%, positive predictive value (PPV) of 64%, negative predictive value (NPV) of 97%, and overall accuracy of 90%. For the detection of distant metastases, PET scans had a sensitivity of 89%, specificity of 97%, PPV of 85%, NPV of 98%, and overall accuracy of 96%. PET scans of the head and neck region performed greater than 1 month after the completion of radiation compared with scans performed within 1 month had a significantly higher sensitivity of 95% versus 55% (P < .01) and NPV of 99% versus 90% (P < .01). Conclusion: PET is effective in detecting distant metastases in the posttreatment surveillance for HNSCC patients. A negative PET is highly reliable for all sites. However, a positive PET in the head and neck region is unreliable because of a high false-positivity rate. PET of the head and neck region has a statistically significant risk of a false-negative reading when performed within 1 month of radiation.
A Thiamin-bound, Pre-decarboxylation Reaction Intermediate Analogue in the Pyruvate Dehydrogenase E1 Subunit Induces Large Scale Disorder-to-Order Transformations in the Enzyme and Reveals Novel Structural Features in the Covalently Bound Adduct

The crystal structure of the E1 component from the Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc) has been determined with phosphonolactylthiamin diphosphate (PLThDP) in its active site. PLThDP serves as a structural and electrostatic analogue of the natural intermediate α-lactylthiamin diphosphate (LThDP), in which the carboxylate from the natural substrate pyruvate is replaced by a phosphonate group. This represents the first example of an experimentally determined, three-dimensional structure of a thiamin diphosphate (ThDP)-dependent enzyme containing a covalently bound, pre-decarboxylation reaction intermediate analogue and should serve as a model for the corresponding intermediates in other ThDP-dependent decarboxylases. Regarding the PDHc-specific reaction, the presence of PLThDP induces large scale conformational changes in the enzyme. In conjunction with the E1-PLThDP and E1-ThDP structures, analysis of a H407A E1-PLThDP variant structure shows that an interaction between His-407 and PLThDP is essential for stabilization of two loop regions in the active site that are otherwise disordered in the absence of intermediate analogue. This ordering completes formation of the active site and creates a new ordered surface likely involved in interactions with the lipoyl domains of E2s within the PDHc complex. The tetrahedral intermediate analogue is tightly held in the active site through direct hydrogen bonds to residues His-407, Tyr-599, and His-640 and reveals a new, enzyme-induced, strain-related feature that appears to aid in the decarboxylation process. This feature is almost certainly present in all ThDP-dependent decarboxylases; thus its inclusion in our understanding of general thiamin catalysis is important.
Healthy older adults’ perceptions of their memory functioning and use of mnemonics

Interview data were gathered from a purposive sample of 40 healthy, articulate older adults (54 to 85 years old, median = 68 years) concerning the events causing memory problems in their everyday activities, the extent to which they felt they had experienced any change in memory as they grew older, and the sorts of memory aids they employed. The examples of forgetting they provided included both retrospective memory failures (the most common and most irritating being the inability to recall someone’s name) and prospective memory failures (e.g., forgetting to get or do a certain thing while out shopping). For each specific type of memory failure, the modal response was of no change with aging, yet 70% of participants reported an increase in memory failure for one or more items. The memory aids most widely reported involved external mnemonics such as writing notes and placing things in conspicuous places so as not to forget them. The pattern of use of mnemonics parallels other data in the literature for younger adults.
Calculation of the electronic structures and spectra of several organic and inorganic radicals containing aluminum

Electronic structure calculations were performed for AlH+, AlH2, AlH3−, AlF+, AlF2, AlH(OH), Al(OH)2, AlFO+, AlCH2, AlH(CH3), Al(CO)2, Al(C2H2) and Al(C2H4). Isotropic hyperfine coupling constants were predicted from unrestricted, MP2-spin-density-matrix-derived Fermi contact integrals and compared with experimental data. This relatively rapid, correlated method appears to be quite consistent and, after application of a roughly 10% scaling factor, reasonably accurate (±0–20 G depending partly on the magnitude of the coupling constant). The method performs poorly, however, when the expected doublet molecular wavefunctions exhibit significant contamination from spin states of higher multiplicity. Based on these results, the spectral assignment of AlFO+ is questioned. The Al(CO)2 complex is shown to have a remarkably small central bond angle and to require consideration of correlation energy to exhibit a bound ground state. Commentary on the aluminum-acetylene and aluminum-ethylene complexes is offered. Theoretical IR data for AlF2, Al(OH)2, AlFO+ and A1(CO)2 are additionally provided.
Road Climbing: Principles Governing Asymmetric Route Choices on Maps

The focus of this paper was on how people plan routes when using maps. This issue is relevant not only to the design of maps, but also to the construction of new navigation systems built to help people plan routes. The research was concerned with the principles that people follow when selecting a route. Specifically, the authors investigated why people's route choices are often asymmetric—why a different route is chosen when traveling between two locations depending on which point is the origin and which is the destination. It is contended that this path asymmetry does not occur randomly; subjects' route selection is systematic and predictable. Often, subjects will employ a heuristic termed here as road climbing, which is similar to hill climbing strategies used in problem-solving. Road climbing is a preference for long and straight routes in the local area containing the origin. In Experiment 1, subjects chose paths predicted by a road climbing model even when the selected paths were 50 per cent longer than alternative paths. Moreover, this effect was exaggerated when subjects processed the maps on a region-by-region basis. In Experiment 2, the results were extended to include real maps that subjects may encounter in their day-to-day routines. These results are discussed in terms of their relevance to current problem-solving and spatial cognition research. Practical applications are also considered.
Mycophenolic acid (cellcept and myofortic) induced injury of the upper GI tract

BackgroundMycophenolic acid (MPA) is an immunosuppressant drug commonly used in patients undergoing solid organ transplant. Although its pattern of inducing injury in the colon is well-known and features prominent crypt apoptosis that mimics graft-versus-host-disease, the injury pattern in the upper
Humor Preference as a Function of Preoedipal Fixation.

Psychoanalytic theory predicts that humor preference is a derivative of unresolved childhood conflicts. Students' Rorschach protocols were analysed to yield measures of preoedipal fixation. The students were given decks of jokes to rank from most to least funny. Results showed that the ranking of jokes was a function of the fixation measures on the Rorschach for women only but not for men.
Solution Phase Combinatorial Chemistry. Discovery of Novel Polyazapyridinophanes with Potent Antibacterial Activity by a Solution Phase Simultaneous Addition of Functionalities Approach

Chemical modification of pre-formed asymmetric polyazaphane scaffolds by simultaneous addition of functionality (letters) in solution has been developed for the preparation of tertiary nitrogen-based combinatorial chemistry libraries. This approach has some significant advantages over the more commonly employed solid phase bead splitting/reaction/mixing procedures for the preparation of libraries. Three novel, asymmetric polyazaphanes 32, 33, and 37 have been synthesized in high yields by an efficient cyclization of 2,6-bis(bromomethyl)pyridine (31) with new orthogonally protected triamines 29, 30, and 35, respectively. Selective deprotection of 32, 33, and 37 provided mono-t-Boc-protected scaffolds 1−3 suitable for solution phase, simultaneous addition of functionalities. Model studies of small libraries of scaffold 2 using CZE analyses indicated that simultaneous addition of 10 benzylic bromide alkylating functionalities would result in libraries containing approximately equimolar amounts of all possibl...
Evaluation of the necessity of postoperative imaging after craniosynostosis surgery

Object Childhood radiation exposure increases the lifetime risk of cancer from an estimated 0.07 to 0.35%. Neurological evaluation of patients after cranial vault reconstruction for synostosis repair is often complicated by pain medication, sedation, intubation, swelling, and dressings; therefore computed tomography (CT) scans are routinely ordered by some surgeons on the 1st postoperative day. The object of this study was to evaluate the utility of these scans. Methods Medical records and CT scans were reviewed for patients at the authors' institution who underwent cranial vault reconstruction to repair synostosis between January 1, 2003, and July 31, 2005. Results Of the 111 patients identified in the review, 84 had a CT scan on postoperative Day 1, and seven of these patients underwent shunt insertion for treatment of hydrocephalus. Thirty-three patients underwent bifrontal craniotomies, whereas 51 underwent total vault reconstruction (TVR). Postoperative CT scans revealed minor contusions in three (9%...
Disease and sprout control in individually film wrapped potatoes

Potatoes (Solanum tuberosum L. cv Russet Burbank) were individually wrapped in Cryovac D-955, a biaxially oriented shrink film, and stored at 24°C. The wrapped potatoes were either treated with a fungicide (thiobendazole), or the film itself was coated with an antimicrobial agent (silicon quaternary ammonium salt) to control diseases that may appear during storage and marketing. Under film wrapped conditions, disease control using a fungicide or antimicrobial agent was not completely successful; however, the marketable qualities of the potatoes were not affected. Disease spread under film wrapped conditions was minimized if the potatoes were disinfected in chlorine (0.5% sodium hypochlorite) and wrapped after they were dried. In another study dormant and post-dormant potatoes were individually film wrapped after they were treated with maleic hydrazide (MH) (pre-harvest treatment) or isopropyl N-(3-chlorophenyl) carbamate (CIPC) (postharvest treatment) for sprout control. Under film wrapped conditions, MH decreased sprouting in the dormant potatoes but not in the post-dormant potatoes. CIPC inhibited sprouting in the post-dormant film wrapped potatoes but was less effective in the dormant potatoes.
Physical organic chemistry of transition metal carbene complexes. 25. Kinetic and thermodynamic acidities of substituted (methylthiophenylcarbene)pentacarbonyl tungsten(0) and (Benzoxymethylcarbene)pentacarbonyl tungsten(0) in aqueous acetonitrile. Evidence for transition state imbalances.

A kinetic study of the reversible deprotonation of substituted (methylthiophenylcarbene)pentacarbonyltungsten(0) ((CO)5WC(SC6H4Z)CH3) and of substituted (benzoxymethylcarbene)pentacarbonyltungsten(0) ((CO)5WC(OCH2C6H4Z)CH3) by primary aliphatic and secondary alicyclic amines in 50% MeCN−50% water (v/v) at 25 °C is reported. From the dependence of the deprotonation rate constants on amine basicity and on carbene complex acidity (variation of Z), Bronsted βB and αCH values, respectively, were obtained. The αCH values were found to be smaller than the βB values. These results indicate a transition state imbalance in which the loss of the carbene complex stabilizing π-donor effect of the OCH2Ar and SAr groups lags behind the proton transfer. These findings confirm a previously formulated hypothesis as to how π-donor groups attached to the carbene carbon of carbene complexes can affect transition state imbalances and mask the experimental manifestation of such imbalances. It is also shown that the transition s...