cssi/SciSciGPT-SciSciNet huggingface dataset:
Concealed anterograde accessory pathway conduction during the induction of orthodromic reciprocating tachycardia

Abstract The purpose of this study was to determine whether concealed anterograde accessory pathway conduction occurs during the induction of orthodromic tachycardia by an artrial extrastimulus (S2). Sixteen patients with an overt (n = 9) or concealed (n = 7) accessory pathway had inducible orthodromic tachycardia by S2during an atrial drive (S1) cycle length of 500 to 650 ms. A ventricular extrastimulus (S3) was introduced coincident with the His depolarization resulting from S2during the longest S1S2interval that reproducibly induced orthodromic tachycardia. The S1S3interval was decreased in 10 ms steps until S3reached ventricular refractoriness. Retrograde accessory pathway conduction of S3in the presence and absence of S2was compared at the same S1S3intervals. In the absence of S2there was retrograde accessory pathway conduction after S3in each patient. In the presence of S2, in patients with overt pre-excitation, retrograde accessory pathway conduction after S3was absent in one patient, prolonged in four patients and present only after long S1S3intervals in three patients. Only one patient had unchanged retrograde conduction regardless of the presence or absence of S2. In patients with a concealed accessory pathway, retrograde accessory pathway conduction after S3was absent in five patients and was prolonged in two. Thus, concealed anterograde accessory pathway conduction was present in 15 of 16 patients at the time of orthodromic tachycardia induction. In conclusion, concealed anterograde accessory pathway conduction occurs in a majority of patients with an overt or a concealed accessory pathway during induction of orthodromic tachycardia by an atrial extrastimulus. In some patients, the initiation of orthodromic tachycardia may depend on a critical interaction between the degree of concealed anterograde accessory pathway conduction and atrioventricular conduction delay after S2.
Formalin preservation of avian blood for metal and DDE analysis.

Field investigators often take blood samples from wild birds for residue analysis to determine their exposure to various environmental contaminants, such as metals and organochlorines. Under field conditions immediate freezing of blood samples, one common technique of preservation, is not always possible or practical. Therefore, specific techniques of blood preservation must be tested to determine which method is most suitable when blood is to be analyzed for contaminants. In addition, techniques of homogenization of formalin-preserved blood must be adequate if such samples are to be analyzed for both organochlorines and metals or for metals requiring different analytical techniques. The objectives of our study were to test the adequacy of a homogenization technique for formalin-preserved blood and determine which of two preservation techniques is better when samples are to be analyzed for metals and DDE.
Temperature derivative spectroscopy to monitor the autoxidation decay of cytochromes P450.

Temperature derivative spectroscopy (TDS), a type of relaxation spectroscopy, is a powerful tool to study protein dynamics (Berendzen, J.; Braunstein, D. Proc. Natl. Acad. Sci. U. S. A.1990, 87, 1). We developed the version of temperature derivative spectroscopy to monitor kinetics of autoxidation of cytochromes P450 and applied it to study the properties of the oxy–ferrous complex of a human membrane bound P450, CYP19A1 (aromatase), and that of a bacterial soluble P450, CYP101 when bound with their most common substrates, androstenedione (AD) and camphor, respectively. TDS extends the panel of methods that can be used to monitor heme protein kinetics, providing a rapid measurement technique and enabling measurement of the autoxidation rate over a wide range of temperatures, yielding the activation energy as well as absolute reaction rate in a single experiment.
Compensatory media use: An exploration of two paradigms

This study explores two major theoretical positions concerning social and parasocial interaction. The Deficiency paradigm predicts that individuals most likely to engage in high television consumption and. high parasocial interaction are those who seek compensation for an impoverished social life resulting from certain personality characteristics. The Global‐Use paradigm posits that media use behavior need not be governed by such a compensation motive. The results of an empirical test indicated that the Deficiency paradigm prevailed when sheer amounts of viewing were considered. When it came to parasocial interaction, the Global‐Use paradigm received more support. Theoretical implications and suggestions for future research are discussed.
Combating spam in tagging systems: An evaluation

Tagging systems allow users to interactively annotate a pool of shared resources using descriptive strings called tags. Tags are used to guide users to interesting resources and help them build communities that share their expertise and resources. As tagging systems are gaining in popularity, they become more susceptible to tag spam: misleading tags that are generated in order to increase the visibility of some resources or simply to confuse users. Our goal is to understand this problem better. In particular, we are interested in answers to questions such as: How many malicious users can a tagging system tolerate before results significantly degradeq What types of tagging systems are more vulnerable to malicious attacksq What would be the effort and the impact of employing a trusted moderator to find bad postingsq Can a system automatically protect itself from spam, for instance, by exploiting user tag patternsq In a quest for answers to these questions, we introduce a framework for modeling tagging systems and user tagging behavior. We also describe a method for ranking documents matching a tag based on taggers' reliability. Using our framework, we study the behavior of existing approaches under malicious attacks and the impact of a moderator and our ranking method.
Texture, color and sensory characteristics of ground beef patties containing bovine blood proteins

Three levels of bovine plasma (BP ; 1.5, 2.5, 3.5%), red cell (RC ; 0.5, 0.75, 1.0%) and decolorized red cell (DC ; 0.75, 1.5, 2.25%) proteins were substituted for lean in ground beef patties. Increased RC decreased HunterLab L * and b * values and DC increased L * values, b * values, nonheme iron, and heme iron in uncooked and cooked patties. Soy-type flavors with BP, bloody and metallic flavors with RC and sour flavors with DC increased compared with control patties. Color, iron, cooking loss, and oxidative stability were minimally changed in ground beef with 0.5% RC, 0.75% DC, or 3.5% BP.
The Adaptive Potential of Hybridization Demonstrated with Bacteriophages

The success or failure of hybrids and the factors that determine their fitness have ecological, evolutionary, medical, and economic implications. Hybrid fitness is a major determinant of the size of hybrid zones and the maintenance of related species with overlapping ranges. It also influences the evolution of emerging pathogens and the success of economically important crop species experimentally hybridized in search of strains with increased yields or disease resistance. Hybrid fitness may largely be determined by the pervasiveness of epistasis in the genome, as epistasis is known to debilitate hybrids through disrupted inter- and intragenic interactions. We identified two bacteriophages isolated from their natural environment, one the result of a past hybridization event involving an ancestor of the other phage and a third, unknown phage. By performing a reciprocal cross of the affected region of the genome, consisting of a single complete gene, we both approximately recreated and reversed this original hybridization event in two chimeric bacteriophage genomes. Subsequent adaptation of the hybrid phages allowed for the recovery of fitness losses incurred by the hybrid genotypes. Furthermore, adaptation led to the ascension of a substantially higher and previously inaccessible adaptive peak. We show that by allowing genotypes to take large leaps across the adaptive landscape rather than single mutational steps, hybridization can lead to huge long-term fitness gains in spite of short-term costs resulting from disrupted epistatic interactions, demonstrating that the success or failure of hybrids may be determined not by their initial fitness, but rather by their adaptive potential.
Intra-articular fibroma of tendon sheath of the shoulder joint: synovial fibroma.

The case of a 30-year-old woman with multiple loose bodies in the shoulder joint is presented. The patient complained of discomfort of her right shoulder. Conventional radiographs failed to reveal any abnormality of the shoulder. On MRI numerous loose bodies were detected that resembled synovial chondromatosis. Histologically, the loose bodies were composed of a benign fibroblastic lesion with diagnostic features of fibroma of tendon sheath, each surfaced by synoviocytes. The clinicopathologic features of intra-articular fibroma of tendon sheath are reviewed. We propose using the term “synovial fibroma” for tumors with histopathologic features of fibroma of tendon sheath arising in the synovium of joints.
Evaluation of ethylene glycol as a cryoprotective agent for blood platelets.

Abstract (1) Ethylene glycol appears to penetrate blood platelets rapidly and is nontoxic in high concentrations. (2) Higher concentrations are tolerated when potassium is present in the suspending medium. (3) Although ethylene glycol satisfied the basic theoretical criteria for a penetrating cryoprotectant, it failed to result in sufficiently high recovery of frozen platelets.
Following Chemical Charge Trapping in Pentacene Thin Films by Selective Impurity Doping and Wavelength‐Resolved Electric Force Microscopy

Charge trapping is one of several factors that limit the performance of organic electronic materials, yet even in pentacene, a prototypical small-molecule semiconductor, the precise chemical nature of charge trapping remains poorly understood. Here the effects of three chemical trap-precursor candidates are examined by layering thin-film pentacene transistors with different pentacene defect species. The resulting charge trapping is studied in each device via scanning-probe electric force microscopy coupled with variable-wavelength sample illumination. Firstly, it is found that layering with pentacen-6(13H)-one (PHO) readily produces uniform charge trapping everywhere in the transistor channel, as expected for an active blanket-deposited trap-precursor. However, layering with 6,13-dihydropentacene (DHP) produces fewer, more-isolated traps, closely resembling the surface potential distribution in pristine pentacene thin films. Secondly, the rates of trap-clearing versus illuminating wavelength (trap-clearing spectra) are measured, revealing enhanced trap-clearing rates at wavelengths assigned to the absorption of either pentacene or the charged trap species. The trap-clearing spectrum for the PHO-layered sample closely resembles the spectrum obtained from pentacene aged in a working transistor, while the trap-clearing spectrum for the DHP-layered sample resembles the spectrum observed in pristine pentacene. We conclude that PHO competently creates traps in pentacene that match the expected trap-clearing spectrum for degraded pentacene, while DHP does not, and that the chemical trap species in aged pentacene is very likely PHO+.
Numerical simulation of aerothermal loads in hypersonic engine inlets due to shock impingement

The effect of shock impingement on an axial corner simulating the inlet of a hypersonic vehicle engine is modeled using a finite-difference procedure. A three-dimensional dynamic grid adaptation procedure is utilized to move the grids to regions with strong flow gradients. The adaptation procedure uses a grid relocation stencil that is valid at both the interior and boundary points of the finite-difference grid. A linear combination of spatial derivatives of specific flow variables, calculated with finite-element interpolation functions, are used as adaptation measures. This computational procedure is used to study laminar and turbulent Mach 6 flows in the axial corner. The description of flow physics and qualitative measures of heat transfer distributions on cowl and strut surfaces obtained from the analysis are compared with experimental observations. Conclusions are drawn regarding the capability of the numerical scheme for enhanced modeling of high-speed compressible flows.
Delay in Diagnosis of Invasive Surgical Site Infections Following Knee Arthroplasty Versus Hip Arthroplasty

Background. The timing of diagnosis of invasive surgical site infection (SSI) following joint replacement surgery is an important criterion used to determine subsequent medical and surgical management. Methods. We compared time to diagnosis of invasive SSI following hip vs knee arthroplasty. SSIs were included in the analysis if they occurred within 365 days following procedures performed from 1 January 2007 through 31 December 2011 at 36 community acute care hospitals and 1 ambulatory surgery center in the Duke Infection Control Outreach Network. A Cox regression model was fitted to estimate the association between procedure type and time to diagnosis of SSI, adjusted for age, pathogen virulence, American Society of Anesthesiologists' score, and hospital surgical volume. Results. Six hundred sixty-one invasive SSIs were identified; 401 (61%) occurred following knee arthroplasties. The median time to diagnosis of SSI was 25 days (interquartile range [IQR], 17–48 days) following hip arthroplasty vs 42 days (IQR, 21–114 days) following knee arthroplasty (unadjusted hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.37–1.87; P < .001). Time to diagnosis of invasive SSI remained significantly shorter for hip than for knee arthroplasties after adjusting for age, pathogen virulence, and hospital surgical volume (HR, 1.51; 95% CI, 1.28–1.78; P < .001). Conclusions. The diagnosis of invasive SSI was delayed following knee arthroplasty compared with hip arthroplasty. We hypothesize that differences in symptom manifestation and disparities in access to care may contribute to the observed differential timing of diagnosis. Our findings have important implications for the management of prosthetic joint infections, because treatment strategies depend on the timing of diagnosis.
Density Functional Study of the Structure, Stability and Oxygen Reduction Activity of Ultrathin Platinum Nanowires

We used density functional theory to study the difference in the structure, stability and catalytic reactivity between ultrathin, 0.5–1.0 nm diameter, platinum nanotubes and nanowires. Model nanowires were formed by inserting an inner chain of platinum atoms in small diameter nanotubes. In this way more stable, non-hollow structures were formed. The difference in the electronic structure of platinum nanotubes and nanowires was examined by inspecting the density of surface states and band structure. Furthermore, reactivity toward the oxygen reduction reaction of platinum nanowires was assessed by studying the change in the chemisorption energies of oxygen, hydroxyl, and hydroperoxyl groups, induced by converting the nanotube models to nanowires. Both ultrathin platinum nanotubes and nanowires show distinct properties compared to bulk platinum. Single-wall nanotubes and platinum nanowires with diameters larger than 1 nm show promise for use as oxygen reduction catalysts.
On the testing of hazard activated open defects

Open defects in CMOS circuits can cause a gate output to go into a high impedance, or “floating” mode, for some input patterns. Since such defects display (large) delay fault behavior, they are commonly assumed to be covered during structural testing by scan based TDF timing tests. TDF tests are generally applied in the launch-on-capture (LOC) scan test mode to avoid “overtesting” the circuit timing from non-functional launch states; also many designs do not support a high speed scan enable to allow at-speed launch-on-shift (LOS) timing tests. Unfortunately, launching timing tests from functional states alone, or even LOC states (which are a superset of functional states), is not sufficient to screen all open defects capable of generating erroneous circuit outputs. CMOS circuits experience a large number of hazards during switching transitions, which result in many more transient logic levels at internal circuit nodes than those predicted by steady state analysis from functional states. Such hazards can activate open defects by precharging a faulty gate output to an incorrect value which is then locked in once the inputs stabilize with the gate output in a high impedance state due to the open. Consequently, many open defects that are commonly assumed to be functionally redundant based on steady state analysis, can in fact be activated in operation and cause circuit failure. These must be targeted during manufacturing tests. In this paper we present a deterministic methodology for targeting hazard activated open defects using not only LOC and LOS tests, but also a new DFT approach that further increases the available test launch states to achieve high coverage. We further show that virtually all of the remaining undetected opens are in fact truly redundant, and do not pose a threat even in the presence of hazards.
Towards Better Fault Localization: A Crosstab-Based Statistical Approach

It is becoming prohibitively expensive and time consuming, as well as tedious and error-prone, to perform debugging manually. Among the debugging activities, fault localization has been one of the most expensive, and therefore, a large number of fault-localization techniques have been proposed over the recent years. This paper presents a crosstab-based statistical technique that makes use of the coverage information of each executable statement and the execution result (success or failure) with respect to each test case to localize faults in an effective and efficient manner. A crosstab is constructed for each executable statement, and a statistic is computed to determine the suspiciousness of the corresponding statement. Statements with a higher suspiciousness are more likely to contain bugs and should be examined before those with a lower suspiciousness. Case studies are performed on both small- (the Siemens and Unix suites) and large-sized programs (space, grep, gzip, and make), and results suggest that the crosstab-based technique (CBT) is more effective (in terms of a smaller percentage of executable statements that have to be examined until the first statement containing the fault is reached) than other techniques, such as Tarantula. Further studies using the Siemens suite reveal that the proposed technique is also more effective at locating faults than other statistically oriented techniques, such as SOBER and Liblit05. Additional experiments evaluate the CBT from other perspectives, such as its efficiency in terms of time taken, its applicability to object-oriented languages (on a very large Java program: Ant), and its sensitivity to test suite size, and demonstrate its superior performance.
Mullerian Inhibiting Substance Regulates Androgen-Induced Gene Expression and Growth in Prostate Cancer Cells through a Nuclear Factor-κB-Dependent Smad-Independent Mechanism

Mullerian inhibiting substance (MIS), a member of the TGFβ superfamily, causes regression of the Mullerian duct in male embryos. The presence of MIS type II and type I receptors in tissues and cell lines derived from the prostate suggests that prostate is a likely target for MIS. In this report, we demonstrate that MIS inhibits androgen-stimulated growth of LNCaP cells and decreases their survival in androgen-deprived medium by preventing cell cycle progression and inducing apoptosis. Expression of dominant-negative Smad1 reversed the ability of MIS to decrease LNCaP cell survival in androgen-deprived medium but not androgen-stimulated growth, whereas abrogation of nuclear factor-κB (NFκB) activation ablated the suppressive effects of MIS on both androgen-stimulated growth and androgen-independent survival. The effect of MIS on androgen-induced growth was not due to changes in androgen receptor expression. However, MIS suppressed androgen-stimulated transcription of prostate-specific antigen; ablation of ...
Contraceptive method switching among American female adolescents, 1979

Better knowledge about contraceptive use in adolescents is needed if pregnancy prevention is to be improved. Data from the 1979 National Survey of Young Women were used to examine method switching once contraceptive use had begun among 449 never-pregnant young women who reported premarital intercourse more than once. Bivariate χ 2 tests and multivariate logit regression were used to examine factors related to switching in four analyses: overall switching; switching among those with one intercourse partner; and switching from nonmedical and medical methods separately. Frequency of intercourse and type of first method had an interactive effect on switching; length of exposure to switching, type of relationship, and reason for choosing the first method were also significant. These results suggest that providers and educators should consider the circumstances under which contraceptive methods are chosen and used by young women when counseling them as to what method may be best for them.
Crystallographic characterization of the PDZ1 domain of the human Na+/H+ exchanger regulatory factor.

The Na+/H+ exchanger regulatory factor (NHERF) contains two PDZ domains that mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. The human NHERF PDZ1 domain, which spans residues 11–99, interacts specifically with carboxy-terminal residues of the β2 adrenergic receptor and the cystic fibrosis transmembrane conductance regulator. The NHERF PDZ1 was expressed in Escherichia coli as a soluble protein, purified and crystallized in the unbound form using the vapor-diffusion method with 2 M ammonium sulfate as the precipitant. Diffraction data were collected to 1.5 A resolution using synchrotron radiation. The crystals belong to space group P3121 or P3221, with unit-cell parameters a = b = 51.6, c = 58.9 A, and one molecule in the asymmetric unit.
Monitoring radioactive compounds in high-performance liquid chromatographic eluates: Fraction collection versus on-line detection

Abstract This study compared two methods of monitoring radioisotopes in high-performance liquid chromatographic eluates (on-line radioactivity detector versus fraction collection and counting). Testing was accomplished by pumping solutions of tritiated water in acetonitrilewater mixtures through the detector or to the fraction collector. At most solvent compositions, the detector's counting efficiency and detection limits were poorer than those of the scintillation counter. However, the reproducibility of the detector data was superior at acetonitrile concentrations of less than 50%. This was attributed to the difficulty in collecting fractions of small equal volumes at the lower organic solvent concentrations in short time intervals. We conclude that on-line monitoring with homogeneous detection is the preferred method for detecting radiolabeled compounds in high-performance liquid chromatographic eluates.
Wideband 220 GHz solid state power amplifier MMIC within minimal die size

A wideband and compact solid state power amplifier MMIC is simulated around 220 GHz. It utilizes 6 μm emitter length common base HBTs from a 250 nm InP HBT technology. Specific power cells and power combiners are simulated in order to minimize the width of the die, which must not exceed 300 μm to avoid multimode propagation in the substrate. Four stages are implemented over a total area of the (275x1840) μm 2 . Simulations of this power amplifier indicate a minimum output power of 14 dBm associated with 16 dB of power gain from 213 GHz to 240 GHz.
Elementary strength theory of cracked beams

Abstract Approximate expressions for stress intensity factors (SIFs), based on energy release rates, of straight, cracked beams are calculated, using the approach proposed by Herrmann et al. [1–3]. Three basic loading conditions are studied: pure bending, pure tension and pure torsion. The SIFs resulting from these cases are used to determine the stress intensity factors of other frequently used specimens of experimental fracture mechanics, e.g. of the single-edge-notch rectangular beam specimen, of three- and four-point bending specimens, the compact tension specimen and of the circumferentially cracked cylinder. Moreover, asymptotic expansions of the SIFs [5] are used to calculate a correction factor β for each case. This factor has recently been introduced (see[4]) in order to achieve a good match with results from the literature.
Nuclear data sheets for A = 48*

Abstract Experimental data available through September 1977 have been reviewed in detail. A summary of information obtained in various reaction and decay experiments is presented, together with adopted level schemes which represent, in the compilers' judgment, the best available nuclear structure information on A = 48 nuclei.
Uterine serous and grade 3 endometrioid carcinomas: is there a survival difference?

BACKGROUND Serous components within endometrial carcinoma are reportedly poor prognosticators. However, to the authors' knowledge the percentage of tumors which must be comprised of a serous component in order to affect outcome is unknown. The authors compared overall survival (OS) in women with endometrial carcinomas comprised of various percentages of uterine serous carcinoma (USC) with that of women with International Federation of Gynecology and Obstetrics (FIGO) Grade 3 endometrioid carcinoma (G3EC) to determine whether outcomes varied between these two poorly differentiated histologies. METHODS Data concerning women with either G3EC or USC who were diagnosed between January 1990 and November 2000 were collected retrospectively. Cases were reviewed to confirm diagnosis and estimate the fraction of tumor comprised of USC. Variables assessed included patient age and race, tumor stage, and lymphovascular space invasion. Associations between variables were tested using the Fisher exact test. The Kaplan–Meier method was used to evaluate OS with comparisons performed using the log-rank test. RESULTS Fifty-two women with G3EC and 87 women with USC were identified. The OS of women with tumors comprised of > 50% USC was found to be significantly worse compared with women with G3EC (hazard ratio [HR] of 2.4; 95% confidence interval [95% CI], 1.2–5.2). Women with USC were more likely to present with extrauterine disease (odds ratio of 2.2; 95% CI, 1.1–4.5). The 5-year survival rate for women with G3EC was 75% compared with 41% for women with tumors that were > 50% USC (P = 0.01). There was a significant trend toward a worse OS in women with even 10% USC compared with women with G3EC. CONCLUSIONS USC involving > 50% of an endometrial carcinoma was found to be predictive of worse OS compared with the OS of women with G3EC. In patients with early-stage disease, a trend toward a worse prognosis was found to exist when USC comprised even 10% of a tumor. Investigation into the treatment of endometrial carcinoma should include and document tumors with any percentage comprised of USC. Cancer 2004. © 2004 American Cancer Society.
Thrombin Generation in Hemorrhage Control and Vascular Occlusion

Hippocrates and Aristotle recognized that blood clots outside the body, but it was not until 1720 that John Louis Petit recognized that control of hemorrhage after amputation was associated with the blood clotting process.1 One hundred thirty-eight years later, Rudolph Virchow formulated his postulates regarding clots in venous thrombosis.2 The association of blood clots with acute arterial occlusion was advanced by James B. Herrick3 in 1912, but the significance of blood clotting in acute arterial events was only resolved by studies in the 1980s.4–6 As a consequence, our knowledge base has largely been driven by studies of the hemostatic process that have been extrapolated to describe the pathological occlusive clotting events in venous and arterial thrombosis. Vascular integrity and blood fluidity are maintained by complex interplay between procoagulant and anticoagulant properties provided by the blood, the vasculature, and subvascular elements. Our knowledge of the inventory and connectivity between the blood-supplied components of the hemostatic and anticoagulant matrix was initially provided by genetic accidents that produced hemostatic and thrombotic defects, most of which have been ratified by experiments conducted with transgenic mice. Additional blood and vascular elements were discovered by use of in vitro assays that identified new entities and required additions to the coagulation/anticoagulation circuits. Pathways for the clotting process were described that were dependent on the plasma coming into contact with a foreign surface (the intrinsic pathway)7–9 or that were associated with the introduction of tissue components (now identified as membrane displayed tissue factor [TF]) into the plasma (the extrinsic pathway; Figure 1A).10,11 However, the absence of bleeding pathology with individuals or transgenic mice that display molecular abnormalities in the factor (F) XII12 and high-molecular-weight kininogen13 components of the contact enzyme (dotted box in …
Cholinesterase activity of muscle fibers and motor end plates: Comparative studies

Abstract Cholinesterase activity of skeletal muscle and its subcellular fractions, including motor end plates, was compared chemically and histochemically in man, mouse, guinea pig, rat, dog, and chicken. The total cholinesterase activity of muscle per milligram of nitrogen was highest in man (4,135 × 10 −9 moles of acetylcholine hydrolyzed in 30 min) and in descending order, decreased in mouse, chicken (red muscle), rat, and dog, to a value of 245 in chicken (white muscle). Cholinesterase was present in all subcellular components fractionated by differential centrifugation, and was greatest in the microsome fraction followed generally, in descending order, by the mitochondria, myofibril, and supernatant fractions. Each of these fractions had greater cholinesterase activity in human muscle than in mouse muscle, and in mouse muscle than in muscle of other species. The ratio of the activities of the microsome fraction and total muscle ranged from 9.5 in man to 2 in guinea pig. Greater concentration of cholinesterase activity was also demonstrated electron microscopically in the sarcotubular system in rat. Because of its relatively greater proportion, the myofibril fraction appears to contribute most to the total cholinesterase activity of muscle. Isolated muscle membrane contained high cholinesterase activity of motor end plates, and the activity was greater than the activity of the microsome fraction in guinea pig, rat, and chicken. The cholinesterase activity per motor end plate was in descending order from 0.805 in the rat, through man, guinea pig, and mouse, to 0.180 in dog, and the variation is less than the variation of the total muscle cholinesterase activity among these species.
Winner-take-all price competition*

We analyze an oligopoly model of homogeneous product price competition that allows for discontinuities in demand and/or costs. Conditions under which only zero profit equilibrium outcomes obtain in such settings are provided. We then illustrate through a series of examples that the conditions provided are “tight” in the sense that their relaxation leads to positive profit outcomes.
MRI contrast enhancement of malignant liver tumours following successful cryoablation.

Objectives To assess the incidence and degree of MRI contrast enhancement in liver tumours following successful percutaneous cryoablation.
Biotechnology and Culture

Biotechnology and Culture. Paul E. Brodwin. ed. Bloomington: Indiana University Press, 2000.287 pp., index.
Factors Associated with First Session Nonattendance at a University-Based Family Therapy Clinic

Two hundred four consecutive psychotherapy initiators who called for an initial appointment at a university-based family therapy clinic during a one-year period were examined to see what factors influenced nonattendance. Researchers considered factors such as demographics, substance use, medical and psychiatric involvement, clinic practice, and constellation expected to attend. The 118 (58%) initiators who kept their appointment differed significantly from the 86 (42%) who did not in distance to the clinic, partner's age, number of children, marital status, employment, time of appointment, and therapeutic constellation. Divorce, unemployment, having a partner between the ages of 18–24, and having children were significant indicators of nonattendance. An appointment scheduled between 1:00 and 4:59 P.M., seeking conjoint psychotherapy, and living between 6 and 25 miles from the clinic were significant indicators of attendance. Implications for improving initial appointment attendance are presented.
ERK1/2 and Egr-1 contribute to increased TNF-α production in rat Kupffer cells after chronic ethanol feeding

Activation of Kupffer cells by lipopolysaccharide (LPS) is a critical step in the pathogenesis of alcoholic liver disease. Kupffer cells isolated from rats fed ethanol in their diet for 4 wk accumu...
Mutations of the Yku80 C Terminus and Xrs2 FHA Domain Specifically Block Yeast Nonhomologous End Joining

The nonhomologous end-joining (NHEJ) pathway of DNA double-strand break repair requires three protein complexes in Saccharomyces cerevisiae: MRX (Mre11-Rad50-Xrs2), Ku (Ku70-Ku80), and DNA ligase IV (Dnl4-Lif1-Nej1). Much is known about the interactions that mediate the formation of each complex, but little is known about how they act together during repair. A comprehensive yeast two-hybrid screen of the NHEJ factors of S. cerevisiae revealed all known interactions within the MRX, Ku, and DNA ligase IV complexes, as well as three additional, weaker interactions between Yku80-Dnl4, Xrs2-Lif1, and Mre11-Yku80. Individual and combined deletions of the Yku80 C terminus and the Xrs2 forkhead-associated (FHA) domain were designed based on the latter two-hybrid results. These deletions synergistically blocked NHEJ but not the telomere and recombination functions of Ku and MRX, confirming that these protein regions are functionally important specifically for NHEJ. Further mutational analysis of Yku80 identified a putative C-terminal amphipathic alpha-helix that is both required for its NHEJ function and strikingly similar to a DNA-dependent protein kinase interaction motif in human Ku80. These results identify a novel role in yeast NHEJ for the poorly characterized Ku80 C-terminal and Xrs2 FHA domains, and they suggest that redundant binding of DNA ligase IV facilitates completion of this DNA repair event.
Estrous Cycle Patterns in Cattle Monitored by Electrical Resistance and Milk Progesterone

An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.
Homologous Recombination Is Very Rare or Absent in Human Influenza A Virus

To determine the extent of homologous recombination in human influenza A virus, we assembled a data set of 13,852 sequences representing all eight segments and both major circulating subtypes, H3N2 and H1N1. Using an exhaustive search and a nonparametric test for mosaic structure, we identified 315 sequences (∼2%) in five different RNA segments that, after a multiple-comparison correction, had statistically significant mosaic signals compatible with homologous recombination. Of these, only two contained recombinant regions of sufficient length (>100 nucleotides [nt]) that the occurrence of homologous recombination could be verified using phylogenetic methods, with the rest involving very short sequence regions (15 to 30 nt). Although this secondary analysis revealed patterns of phylogenetic incongruence compatible with the action of recombination, neither candidate recombinant was strongly supported. Given our inability to exclude the occurrence of mixed infection and template switching during amplification, laboratory artifacts provide an alternative and likely explanation for the occurrence of phylogenetic incongruence in these two cases. We therefore conclude that, if it occurs at all, homologous recombination plays only a very minor role in the evolution of human influenza A virus.
Survival of translocated Greater Sage-Grouse hens in northeastern California

ABSTRACT. Translocation success of Greater Sage-Grouse (Centrocercus urophasianus) is generally measured by documenting whether translocated individuals survive and reproduce at the release site. However, demographic parameters, such as annual survival of translocated individuals, provide a more accurate measure of translocation success. We translocated 60 female sage-grouse from Oregon and Nevada to Clear Lake National Wildlife Refuge, California, during 2005–2010 to augment a small population of resident grouse. We radio-marked each translocated female and a sample of resident female sage-grouse, recorded their locations, and monitored their survival at monthly intervals over the study period. We observed most (55/60) translocated birds near (< 100 m from) the only lek in the study area within one week of their release. To examine factors influencing survival, we developed a set of a priori models that included the effects of translocation status, season (breeding vs. nonbreeding), year, and age on annu...
Impact of a coordinated tuberculosis Team in an inner-city hospital in New York City.

Objective: To evaluate the impact of a coordinated approach for the isolation, diagnosis, and treatment of patients with tuberculosis. Design: Retrospective cohort study. Setting: Bronx-Lebanon Hospital Center, an inner-city hospital in the South Bronx, New York City. Patients: Patients with smear-positive, culture-confirmed pulmonary tuberculosis. Interventions: Institution of a coordinated tuberculosis team. Results: Admissions of 46 patients before and 39 patients after the formation of a tuberculosis team were reviewed. Before institution of the tuberculosis team, 35% of patients were isolated within 24 hours of presentation, 41% never were isolated, and the mean number of days patients were not isolated was 19. After implementation of the tuberculosis team, 59% of patients were isolated within 24 hours, only 5% were never isolated, and the mean number of days patients were not isolated was 3.5. These differences were statistically significant. There also was a corresponding decrease in length of hospitalization. In addition, there were noticeable improvements in patient and staff morale and attitudes. Conclusions: The tuberculosis team likely has decreased the risk of nosocomial tuberculosis transmission by increasing the proportion of infectious tuberculosis patients admitted into AFB isolation and by reducing (by 780) the number of days out of isolation while smear positive. There also were concomitant financial savings.
Social and extra-pair mating in relation to major histocompatibility complex variation in common yellowthroats

Females are thought to gain better-quality genes for their offspring by mating with particular males. Genes of the major histocompatibility complex (MHC) play a critical role in adaptive immunity, and several studies have examined female mate choice in relation to MHC variation. In common yellowthroats, females prefer males that have larger black facial masks, an ornament associated with MHC variation, immune function and condition. Here we also tested whether mating patterns are directly correlated with MHC diversity or similarity. Using pyrosequencing, we found that the presence of extra-pair young in the brood was not related to male MHC diversity or similarity between the female and her within-pair mate. Furthermore, extra-pair sires did not differ in overall diversity from males they cuckolded, or in their similarity to the female. MHC diversity is extremely high in this species, and it may limit the ability of females to assess MHC variation in males. Thus, mating may be based on ornaments, such as mask size, which are better indicators of overall male health and genetic quality.
Knot and Link Invariants

In this chapter we make some historical observations and comment on some early work in knot theory. Invariants of knots and links are introduced in Section 11.2. Witten’s interpretation of the Jones polynomial via the Chern–Simons theory is discussed in Section 11.3. A new invariant of 3-manifolds is obtained as a byproduct of this work by an evaluation of a certain partition function of the theory. We already met this invariant, called the Witten–Reshetikhin–Turaev (or WRT) invariant in Chapter 10. In Section 11.4 we discuss the Vassiliev invariants of singular knots. Gauss’s formula for the linking number is the starting point of some more recent work on self-linking invariants of knots by Bott, Taubes, and Cattaneo. We will discuss their work in Section 11.5. The self-linking invariants were obtained earlier by physicists using Chern–Simons perturbation theory. This work now forms a small part of the program initiated by Kontsevich [235] to relate topology of low-dimensional manifolds, homotopical algebras, and non-commutative geometry with topological field theories and Feynman diagrams in physics. See also the book [176] by Guadagnini. Khovanov’s categorification of the Jones polynomial by Khovanov homology is the subject of Section 11.6. We would like to remark that in recent years many applications of knot theory have been made in chemistry and biology (for a brief of discussion of these and further references see, for example, [260]). Some of the material in this chapter is from my article [263]).
Exports, Imports, Domestic Output, and Employment

I. Relation between the effects of foreign trade and the structural characteristics of the national economy, 171. — Allocation of imports, 172. — Relation between "ultimate" demand and derived output and employment, 174. — Exports as an independent variable, 175. — Dependent and secondary exports, 177. — II. Formulation in precise quantitative terms, 178. — III. Relation between exports and employment in the United States in 1939: entire exports as part of final demand, including household consumption and domestic investment, 184; demand for consumers' goods not independent, 185; net terms of trade allowed for, 186. — General observations, 186.
SMALL DAMS AS BARRIERS TO FRESHWATER MUSSELS (BIVALVIA, UNIONOIDA) AND THEIR HOSTS

Abstract The distributions of two unionoids (fragile papershell Leptodea fragilis and pink heelsplitter Potamilus alatus) were examined in five North American Midwest river systems in relation to the location of dams on the rivers. These dams were non-navigational (without locks), lacked fish ladders, and varied in height from 1 to 17·7 m. Both species were restricted in their distribution to the river downstream of the dams. This suggests that the host fish(es) of these species was unable to move upstream of these obstacles. Both unionoids are believed to parasitize the freshwater drum Aplodinotus grunniens. Several endangered unionoid species also may use this fish, or other dam-limited fishes, as hosts. Dams, even lowhead structures, may contribute to the overall depletion of unionoids by artificially restricting their distributions and isolating populations from each other. Management practices for endangered fishes and mussels must take into account these physical obstacles.
Conceptual and Epistemic Aspects of Students' Scientific Explanations

This article explores how students' epistemological ideas about the nature of science interact with their conceptual understanding of a particular domain, as reflected in written explanations for an event of natural selection constructed by groups of high school students through a technology-supported curriculum about evolution. Analyses intended to disentangle conceptual and epistemic aspects of explanation reveal that groups sought plausible causal accounts of observed data, and were sensitive to the need for causal coherence, while articulating explanations consistent with the theory of natural selection. Groups often failed to explicitly cite data to support key claims, however, both because of difficulty in interpreting data and because they did not seem to see explicit evidence as crucial to an explanation. These findings reveal that students have productive epistemic resources to bring to bear during inquiry, but highlight the need for an epistemic discourse around student-generated artifacts to de...
Younger age of menopause in women with cerebral aneurysms

Background The incidence of subarachnoid hemorrhage in women surges following menopause. Estrogen fluctuations have been implicated in cerebral aneurysm formation, growth and rupture and are thought to explain the well-known gender disparity. The aim of this study was to examine the association between age at menopause, which can determine lifetime estrogen exposure, and the presence of cerebral aneurysms. Methods A retrospective case-control study was conducted by interviewing postmenopausal women with intradural cerebral aneurysms about their basic medical and gynecologic histories. This information was compared with the same data points collected from 4682 women contacted through random digit phone dialing in the National Institute of Child Health and Human Development-sponsored Contraceptive and Reproductive Experiences Study published in 2002. Results Among 76 consecutive postmenopausal women with cerebral aneurysms who were treated by a single physician and interviewed, multivariate logistic regression showed that later menopause age (OR 0.79, CI 0.63 to 0.996, p=0.046) was significantly associated with a lower aneurysm incidence. Premature menopause ( Conclusion There is a trend showing that an earlier age at menopause is associated with the presence of a cerebral aneurysm. This suggests that loss of estrogen earlier in a woman9s life may contribute to the pathogenesis of cerebral aneurysm. These data may identify a risk factor for cerebral aneurysm pathogenesis and also a potential target for future therapies.