cssi/SciSciGPT-SciSciNet huggingface dataset:
A Dislocation Simulation Approach to Physical Basis of Master Curve

Discrete dislocation simulations of crack-tip plasticity are used to study the sharp increase in fracture toughness around ductile-brittle transition temperature of ferritic steels. The model used composed of a macrocrack with a microcrack ahead of it in its crack plane. The microcrack represents potential fracture sites at internal inhomogenities, such as brittle precipitates. The simulation has two stages: at first the fracture stress of microcrack, σF is calculated from dislocation simulation of microcrack-tip plasticity. In the next stage the fracture toughness is estimated by the macrocrack tip plasticity simulation; the fracture toughness is applied stress intensity at the macrorack when the tensile stress at the microcrack position attains σF . The brittle-ductile transition curve is obtained by determining the fracture toughness at various temperatures. Factors that contribute to the sharp upturn in fracture toughness with increasing temperature are found to be the increase in dislocation mobility, the decrease in tensile stress ahead of the macrocrack tip due to blunting and increase in mircocrack fracture stress due to increase in plasticity at the microcrack tips. The shape of the curve obtained is similar to the Master Curve.© 2008 ASME
Hypothermic Cardioprotection Attenuates Mitochondrial Permeability Transition Pore Opening and Calcium Loading in Isolated Cardiac Mitochondria

Ischemia-reperfusion injury (IRI) is associated with mitochondrial permeability transition pore (mPTP) opening and impaired mitochondrial respiration. Hypothermia attenuates IRI. We examined mitochondrial function in mitochondria obtained from isolated hearts subjected to warm or cold ischemia. Guinea pig isolated hearts were perfused at constant pressure with Krebs-Ringer's solution at 37°C and subjected to 30 min global ischemia at 37°C or 17°C. After 5 min of reperfusion mitochondria were isolated. Mitochondrial [Ca2+]m, membrane potential (ΔΨm), and NADH were measured by spectrophotometry at appropriate wavelengths with indo-1, BCECF, rhodamine 123 fluorescent dyes, and autofluorescence, respectively. After energizing with pyruvic acid, 0-100 μM CaCl2 (0.03-60 μM free [Ca2+]e) was added followed by 250 μM ADP. Ca2+ -induced mPTP opening was assessed by collapse of ΔΨm. 10 μM [Ca2+]e resulted in mPTP opening after 37°C IRI, but only at 35 μM [Ca2+]e after 17°C IRI. ADP decreased ΔΨm and NADH and increased [Ca2+]m in all mitochondria, but the fall in ΔΨm was greater and the responses to ADP with Ca2+ overloading were worse after 37°C IRI vs. 17°C IRI. The incidence of no state 4 respiration was 25% with no added CaCl2 after 37°C IRI and 0% after 17°C IRI. This study shows that hypothermia prevents IRI damage through pathways restricting mitochondrial Ca2+ loading and preserves mitochondrial redox state and respiration. Moreover, mitochondria protected during ischemia with hypothermia were more resistant to Ca2+-induced mPTP opening and oxidative phosphorylation was better preserved. Hypothermia might prevent conformational changes in the F1F0-ATPsynthase and the ADP/ATP carrier, leading to better mitochondrial function and a resistance to mPTP opening as the ADP/ATP carrier is associated with mPTP opening.
Syntheses of cyclic prodrugs of RGD peptidomimetics with various macrocyclic ring sizes: evaluation of physicochemical, transport and antithrombic properties.

The objective of this work was to synthesize cyclic prodrugs 1a-d of RGD peptidomimetics 2a-d with various ring sizes (n[CH2] = 1, 3, 5 and 7) and to evaluate the effect of ring size on their transport, physicochemical, enzymatic stability, and antithrombic properties. The syntheses of cyclic prodrugs 1a-d were achieved by converging two key intermediates, Boc-Phe-O-CH2-OCO-OpNP (5) and H2N-(CH2)n-CO-Asp(OBzl)-OTce (8a-d), to give linear precursors Boc-Phe-O-CH2-OCO-HN-(CH2)n-CO-Asp(OBzl)-OTce (9a-d). The N- and C-terminus protecting groups were removed from 9a-d to give 10a-d. Linear precursors 10a-d were cyclized, and the remaining Bzl-protecting group was removed to produce cyclic prodrugs 1a-d in around 20% overall yield. The linear RGD peptidomimetics (2a-d) were synthesized using standard Boc-amino acid chemistry by solution-phase method. Increasing the ring size by adding methylene groups also increases the hydrophobicity of the cyclic prodrugs and parent RGD peptidomimetics. The transport properties of cyclic prodrugs 1c and 1d were 2.6- and 4.4-fold better than those of parent compounds 2c and 2d, respectively. These results suggest that increasing the hydrophobicity of the cyclic prodrugs and parent RGD peptidomimetics enhanced their transport properties. The hydrodynamic radii of the cyclic prodrugs were also smaller than those of their respective parent compounds, suggesting that the change in size may contribute to their transport properties. The chemical stability of the cyclic prodrugs was affected by the ring size, and the cyclic prodrug with the larger ring size (i.e. 1d) was more stable than the smaller one (i.e. 1a). All the cyclic prodrugs were more stable at pH 4 than at pH 7 and 10. Prodrug-to-drug conversion could be induced by isolated esterase as well as esterase found in human plasma. An increase in the length of methylene group (n[CH2] = 1, 3, 5, 7) enhanced the antithrombic activity of the prodrugs and the parent compounds. In summary, the ring size of cyclic prodrugs affected their transport, physicochemical, and antithrombic properties.
Systemic lupus erythematosus and sickle cell disease

A case of 10-year-old girl with an unusual association of sickle cell disease (SCO) with systemic lupus erythematosus (SLE) is presented. The report discusses the clues to the diagnosis of this rare combination with review of relevant literature and highlights the diagnostic dilemma that may arise because of the similarity of symptoms.
A surrogate method for comparison analysis of salivary concentrations of Xylitol-containing products.

Xylitol chewing gum has been shown to reduce Streptococcus mutans levels and decay. Two studies examined the presence and time course of salivary xylitol concentrations delivered via xylitol-containing pellet gum and compared them to other xylitol-containing products. A within-subjects design was used for both studies. Study 1, adults (N = 15) received three xylitol-containing products (pellet gum (2.6 g), gummy bears (2.6 g), and commercially available stick gum (Koolerz, 3.0 g)); Study 2, a second group of adults (N = 15) received three xylitol-containing products (pellet gum, gummy bears, and a 33% xylitol syrup (2.67 g). For both studies subjects consumed one xylitol product per visit with a 7-day washout between each product. A standardized protocol was followed for each product visit. Product order was randomly determined at the initial visit. Saliva samples (0.5 mL to 1.0 mL) were collected at baseline and up to 10 time points (~16 min in length) after product consumption initiated. Concentration of xylitol in saliva samples was analyzed using high-performance liquid chromatography. Area under the curve (AUC) for determining the average xylitol concentration in saliva over the total sampling period was calculated for each product. In both studies all three xylitol products (Study 1: pellet gum, gummy bears, and stick gum; Study 2: pellet gum, gummy bears, and syrup) had similar time curves with two xylitol concentration peaks during the sampling period. Study 1 had its highest mean peaks at the 4 min sampling point while Study 2 had its highest mean peaks between 13 to 16 minutes. Salivary xylitol levels returned to baseline at about 18 minutes for all forms tested. Additionally, for both studies the total AUC for the xylitol products were similar compared to the pellet gum (Study 1: pellet gum – 51.3 μg.min/mL, gummy bears – 59.6 μg.min/mL, and stick gum – 46.4 μg.min/mL; Study 2: pellet gum – 63.0 μg.min/mL, gummy bears – 55.9 μg.min/mL, and syrup – 59.0 μg.min/mL). The comparison method demonstrated high reliability and validity. In both studies other xylitol-containing products had time curves and mean xylitol concentration peaks similar to xylitol pellet gum suggesting this test may be a surrogate for longer studies comparing various products.
Origin of Cooperativity in the Activation of Fructose-1,6-bisphosphatase by Mg2+

Abstract Fructose-1,6-bisphosphatase requires a divalent metal cation for catalysis, Mg2+ being its most studied activator. Phosphatase activity increases sigmoidally with the concentration of Mg2+, but the mechanistic basis for such cooperativity is unknown. Bound magnesium cations can interact within a single subunit or between different subunits of the enzyme tetramer. Mutations of Asp118, Asp121, or Glu97 to alanine inactivate the recombinant porcine enzyme. These residues bind directly to magnesium cations at the active site. Three different hybrid tetramers of fructose-1,6-bisphosphatase, composed of one wild-type subunit and three subunits bearing one of the mutations above, exhibit kinetic parameters (Km for fructose-1,6-bisphosphate, 1.1–1.8 μm; Ka for Mg2+, 0.34–0.76 mm; Ki for fructose-2,6-bisphosphate, 0.11–0.61 μm; and IC50 for AMP, 3.8–7.4 μm) nearly identical to those of the wild-type enzyme. Notwithstanding these similarities, the kcat parameter for each hybrid tetramer is approximately one-fourth of that for the wild-type enzyme. Evidently, each subunit in the wild-type tetramer can independently achieve maximum velocity when activated by Mg2+. Moreover, the activities of the three hybrid tetramers vary sigmoidally with the concentration of Mg2+ (Hill coefficients of ∼2). The findings above are fully consistent with a mechanism of cooperativity that arises from within a single subunit of fructose-1,6-bisphosphatase.
The ‘tailored’ CCSD(T) description of the automerization of cyclobutadiene

Abstract An alternative route to extend the CCSD(T) approach to multireference problems is presented. The well-known defect of the CCSD(T) model in describing the non-dynamic electron correlation effects is remedied by ‘tailoring’ the underlying coupled-cluster singles and doubles (CCSD) approach and applying the perturbative triples correction to it. The TCCSD(T) approach suggested in the paper has the same computational demands as the CCSD(T) method, though being mostly free from its drawbacks pertinent to multireference (quasidegenerate) situations. To test the approach we calculate the potential energy surface for the automerization of cyclobutadiene where the transition state exhibits a strong multireference character.
THE PHYSIOLOGIC ACTIVITY OF Z-TRIIODOTHYRONINE*

IN a previous communication dealing with the physiologic activity of various analogues of thyroxine, Lerman, Harington, and Means (1) pointed out that any change in the structure of the thyroxine molecule resulted in a compound with activity less than that of l-thyroxine. It is, therefore, not surprising that the reports by Gross and Pitt-Rivers (2) of a compound, l-triiodothyronine, with biologic activity greater than that of l-thyroxine aroused a good deal of interest. When this material became available,1 its biologic effect was observed in several patients with myxedema. It is the purpose of this paper to report on the activity of l-triiodothyronine in humans and also on its effect in certain phases of iodine metabolism. The compound, 3,5,3′-Z-triiodothyronine, was assayed in 4 patients with myxedema. The material was administered daily in dosage of 0.1 mg. intravenously and the resulting changes in the basal metabolic rate were compared with those observed in our standard assays of thyroxine polypept...
Organization of Strongly Interacting Directed Polymer Liquids in the Presence of Stringent Constraints

The impact of impenetrable obstacles on the energetics and equilibrium structure of strongly repulsive directed polymers is investigated. As a result of the strong interactions, regions of severe polymer depletion and excess are found in the vicinity of the obstacle, and the associated free-energy cost is found to scale quadratically with the average polymer density. The polymer-polymer interactions are accounted for via a sequence of transformations: from the 3D line liquid to a 2D fluid of Bose particles to a 2D composite fermion fluid and, finally, to a 2D one-component plasma. The results presented here are applicable to a range of systems consisting of noncrossing directed lines.
Improving electro-optic window reliability with DIACER coatings

Most commercial diamond synthesis processes involve some form of chemical vapor deposition (CVD) which results in heterogeneous nucleation on the surface of window or dome materials. Generally, these processes have relatively long deposition times driven by the slow CVD kinetics. An alternate method called DIACERTM uses an aqueous seed crystal dispersion applied to the window substrates prior to CVD. These seed crystals reduce nucleation times and speed CVD deposition rates. Thicker coatings can be produced by repeating the seeding/CVD cycle until the required thickness is achieved. This paper reviews DIACERTM coating results on silicon substrates. Scanning electron microscopy and atomic force microscopy images of images of the coatings are presented. IR transmission results are presented both before and after sand and rain erosion exposures. The results of this testing will show DICERTM coatings to durable for the protection of silicon substrates after exposure to severe sand environments.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Lower Esophageal Sphincter Is Achalasic in nNOS−/− and Hypotensive in W/Wv Mutant Mice

Background & Aims: It has been proposed that nitrergic nerves mediate lower esophageal sphincter (LES) relaxation with intramuscular interstitial cells of Cajal (ICC-IM) as an intermediary. Dysfunction of the nitrergic pathway has been shown to cause LES hypertension and impaired relaxation in achalasia. We determined whether mice with neuronal nitric oxide synthase gene disruption (nNOS−/−) and W/Wv mice lacking ICC-IM have achalasia-like LES dysfunction. Methods: Intraluminal manometry using a customized micro-sized catheter assembly was performed in anesthetized mice. Basal LES pressure and swallow- and vagal-evoked LES relaxations were quantified in wild-type, Nω-nitro-l-arginine methyl ester HCl salt (l-NAME)-treated, nNOS−/−, and W/Wv mice. Results: Wild-type mouse LES maintained a basal pressure (24 ± 3 mm Hg; N = 8) and relaxed normally to swallow (87% ± 3%; N = 8) and vagal stimulation (91% ± 4% mm Hg; N = 6). Pretreatment with l-NAME (100 mg/kg, intravenously) attenuated LES relaxation to both stimuli (P < 0.05). The LES in nNOS−/− was significantly hypertensive (36 ± 5 mm Hg; N = 10; P < 0.05) with a markedly impaired relaxation (P < 0.05). In contrast, W/Wv mouse LES was significantly hypotensive (11 ± 2 mm Hg; N = 6; P < 0.05) with normal relaxation that was blocked by l-NAME. Conclusions: nNOS−/− mice have LES hypertension with impaired relaxation resembling achalasia. In contrast, W/Wv mice have hypotensive LES with unimpaired relaxation, suggesting that ICC-IM do not play a role in nitrergic neurotransmission.
Peripheral haemodynamic effects of electronarcosis.

The effects of electronarcosis on peripheral haemodynamics were studied in the isolated forelimb preparation of the dog. Forelimbs of dogs under nembutal anaesthesia were severed from the body and perfused at constant flow rate by a Sigma motor pump with blood drawn from animals under electronarcosis. It was found that blood from animals under electronarcosis consistently caused vasoconstriction in the isolated forelimb which could be blocked partially by phentolamine. It is concluded that electronarcosis causes the release of vasoactive substances into the circulation, the bulk of which appear to be catecholamines.
Femtosecond dynamics of hydrogen elimination: benzene formation from cyclohexadiene

Using femtosecond-resolved mass spectrometry in a molecular beam, we report real-time study of the hydrogen elimination reaction of 1,4-cyclohexadiene. The experimental observation of the ultrafast stepwise H-elimination elucidates the reaction dynamics and mechanism. With density-functional theory (ground-state) calculations, the nature of the reaction (multiple) pathways is examined. With the help of recent conical-intersection calculations, the excited-state and ground-state pathways are correlated. From these experimental and theoretical results we provide a unifying picture of the thermochemistry, photochemistry and the stereochemistry observed in the condensed phase.
Cleavage of the ether bond of phenylmethyl ethers by enzymes of Arthrobacter sp

Abstract On the basis of the sequential induction technique, it appeared that m -hydroxybenzoate and gentisate were formed from m -methoxybenzoate and that protocatechuate was produced from vanillate by Arthrobacter sp. Enzymes of this bacterium converted m -methoxybenzoate to m -hydroxybenzoate and vanillate to protocatechuate; the products were identified by thin-layer chromatography, gas chromatography, and mass spectrometry. Formaldehyde was formed in the cleavage of the ether linkage of m -methoxybenzoate and vanillate. Formaldehyde accumulated in the presence of semicarbazide, and it was identified by thin-layer chromatography and infrared spectrometry of its 2,4-dinitrophenylhydrazine derivative. For the enzymatic cleavage of the ether bond of m -methoxybenzoate, O 2 and a reduced pyridine nucleotide were required. Enzymes of this microorganism also generated formaldehyde from other methoxy compounds.
Reactivity of Platinum−Oxygen Bonds: Kinetic and Mechanistic Studies of the Carbonylation of Platinum Aryloxide Complexes and the Formation of (Aryloxy)carbonyls

The reactions of [Pt(triphos)(Cl)][Cl] (1) {triphos = bis[2-(diphenylphosphino)ethyl]phenylphosphine} with NaOC6H4-p-R, in the presence of NaPF6, yields the aryloxy complexes [Pt(triphos)(OC6H4-p-R)][PF6] (R = OMe (2a), Me (2b), H (2c), F (2d), Cl (2e)). Upon reaction of 2a−e with carbon monoxide at pressures from 10 to 134 psi in acetonitrile the (aryloxy)carbonyl complexes [Pt(triphos)(C(O)OC6H4-p-R)][PF6] (3a−e) were obtained. The molecular structure of [Pt(triphos)(C(O)OC6H4-p-Me)][PF6] (3b) was determined by X-ray diffraction. Complex 3b crystallized in the monoclinic space group P21/n (no. 14) with a = 10.797(1) A , b = 19.927(3) A, c = 19.113(2) A, β = 98.07(1)°, V = 4071(2) A3, and Z = 4. The structure was solved and refined to R = 0.035 and Rw = 0.040 for 3958 reflections with I > 3σ(I). The kinetics of the carbonylation of 2a−e to form 3a−e were studied by 31P{1H} NMR. Rates of carbonylation exhibit a first order dependence on [CO], but are independent of the concentration of free aryloxide in s...
The Triplet Potential Energy Surface of s-trans-2,4-Hexadiene. A Comparison of Theory and Experiment

The mechanism of s-trans-2,4-hexadiene triplet interconversion has been explored using the B3LYP method with 6-31+G(d,p) and cc-pVTZ basis sets. Nine stationary points are located on the T1 surface and five on the S0 surface of s-trans-2,4-hexadiene. The results are consistent with experimental observations that indicate that the triplet-state photoisomerization of the 2,4-hexadiene involves the interconversion of allylmethylene triplet intermediates. Furthermore, this equilibration is predicted to proceed via readily accessible planar triplet intermediates which are nearly isoenergetic. The accessibility of planar triplet intermediates is consistent with triplet excitation transfer steps between the diene isomers that are responsible for the observed quantum chain process in the photoisomerization of the 2,4-hexadienes.
Editing and Imputation for Quantitative Survey Data

Abstract This article develops a three-stage strategy for cleaning survey data with missing and outlying values: (a) detection of outlying cases, (b) detection of outlying values within outlying cases, and (c) imputation of likely values for missing and/or outlying and edited values. Methodological tools include distance measures, graphical procedures, and maximum likelihood and robust estimation for incomplete multivariate normal data. Data from the Annual Survey of Manufactures (ASM) are used to illustrate the method.
Multivariate Analysis of Clinical, Demographic, and Laboratory Data for Classification of Disorders of Calcium Homeostasis

Parathyroid hormone (PTH) nomograms combine total calcium and intact PTH (iPTH) measurements to classify disorders of calcium homeostasis. Our objective was to determine if using a combination of laboratory, demographic, and clinical parameters improves the accuracy of classification of these disorders. Chart data were collected for 236 patients with physician-ordered iPTH and total calcium tests. Classification was done using 3 approaches: (1) PTH nomogram plotting total calcium and iPTH results against known cases; (2) review of all available chart data (“gold standard”); and (3) multivariate model (classification and regression tree [CART] or logistic regression) using 24 variables. The CART model was developed using the gold standard patient classification and validated using leave-one-out cross-validation. The CART model was significantly ( P = .002) more accurate (80.6%) than the PTH nomogram (59.7%) and logistic regression (66.2%) at classifying calcium homeostasis disorders. The CART model used 6 of 24 variables (iPTH, calcium, creatinine, renal transplantation, percentage of females, and urea nitrogen) and had a misclassification error rate of 0.194 (27/139). Classification of disorders of calcium homeostasis based on the PTH nomogram can be improved by using the CART model developed in this study.
Modelling: when and why?

Over the past fifteen years, neuroreceptor imaging with positron emission tomography (PET) and single-photon emission tomography (SPET) has been used for the visualization and quantification of a number of receptors and transporters in the living human brain, such as dopamine, serotonin, benzodiazepine, and opiate receptors. This imaging technique has led to the characterization of alterations in receptor density in various neuropsychiatric conditions, and the study of receptor occupancy associated with pharmacological treatments and side-effects. In addition, recent developments in the field indicate that the same imaging methods can be used for the measurement of fluctuations of transmitter levels in the vicinity of these receptors [1].
Activation of Phospholipase D by Phosphatidic Acid ENHANCED VESICLE BINDING, PHOSPHATIDIC ACID-Ca2+ INTERACTION, OR AN ALLOSTERIC EFFECT?

The activity of bacterial phospholipase D (PLD), a Ca2+-dependent enzyme, toward phosphatidylcholine bilayers was enhanced 7-fold by incorporation of 10 mol % phosphatidic acid (PA) in the vesicle bilayer. Addition of other negatively charged lipids such as phosphatidylinositol, phosphatidylmethanol, and oleic acid either inhibited or had no effect on enzyme activity. Only negatively charged lipids with a free phosphate group, phosphatidylinositol 4-phosphate and lyso-PA, had the same effect as PA on enzyme activity. Changes in vesicle curvature and fusion were not the reason for PA activation; rather, a metal ion-induced lateral segregation of PA in the vesicle bilayer correlated with PLD activation. Significant PA activation was also observed with monomer phosphatidylcholine substrate upon the addition of PA vesicles. The PA activation was caused by Ca2+·PA interacting with PLD at an allosteric site other than active site.
Defining the patient at high risk for melanoma

In this practical review, we aim to help clinicians identify patients who are at significant risk of developing malignant melanoma. Universal screening is challenging, thus it is important to effectively single out patients who have a high risk of developing the disease. We provide a summary of pertinent questions to review when taking the patient's history, point out the phenotypic features to note during skin examination, and suggest risk stratification as a means to plan initial and long-term surveillance strategy. We mention personal and family history of melanoma as prime risk factors for melanoma, yet the review also focuses on the patient who has no history of melanoma, either in himself or his family, and the proper ways to evaluate his likelihood of developing the disease.
A More Effective Training Approach for Contemporary Policing

Training is an important tool in the process of facilitating change within police organizations. With the further implementation of community oriented policing strategies, the form and content of training curricula has increasingly become an area of scholarly focus. Likewise, the methods that police instructors use to teach subjects is of equal importance. Many police trainers rely heavily on a lecture- and teacher-centered approach when imparting knowledge to both neophyte and veteran police officers. Police trainers might benefit from a more student-centered instructional format. This article examines incorporating the theory of andragogy into police training. By utilizing andragogy, police officers will become more active and involved in the learning process. This approach may also help officers become more self-directed and in doing so reflect the trend toward community oriented policing.
Ibutilide: efficacy and safety in atrial fibrillation and atrial flutter in a general cardiology practice.

Background: Published experience with ibutilide (IB) in randomized clinical trials reveals that conversion to sinus rhythm (SR) occurs in 31% of patients with atrial fibrillation (AF) and in 63% of patients with atrial flutter. Hypothesis: The study was undertaken to test the efficacy and safety of IB in patients with AF and with atrial flutter and to compare them with those reported in previous studies. Methods: in a general cardiology practice, 54 consecutive patients with AF or atrial flutter, no contraindication to IB, and a normal QTc interval, were treated with intravenous IB (0.4–2.0 mg). Duration of arrhythmia, left atrial (LA) size, ejection fraction (EF), time to conversion, QTc interval, and adverse drug events were determined. Patients were observed for a minimum of 6 h. Successful cardioversion was defined as arrhythmia termination within 6 h. Results: Twenty-four of 34 (70.6%) patients with AF and 15 of 20 (75%) patients with atrial flutter converted to SR. Conversion of AF to SR was more likely to occur if duration of AF was ˜ 96 h compared with > 96 h (81 vs. 17%, respectively; p = 0.006). The mean time to arrhythmia termination was 68.8 min. Left atrial size, determined by echocardiogram, was 44 ± 13 mm in 43 patients. Patients with LA size > 45 mm had a conversion rate of 55% in both AF and flutter, compared with a conversion rate of 72% in patients with LA size < 45 mm. Ejection fraction was not a predictor of drug success. The QTc intervals were significantly prolonged after IB administration, with a mean change of 47.1 ms for successfully treated patients. Sustained polymorphic ventricular tachycardia occurred in one patient within 1 min of IB infusion, requiring electrical cardioversion to SR. This patient's serum electrolytes and QTc interval were normal prior to IB infusion; however, the QTc increased by 160 ms (from 387 to 547 ms) during drug infusion. No systemic or pulmonary emboli occurred. Conclusion: The efficacy of IB for conversion of AF to SR in this prospective observational study was considerably better than previously reported. Duration of AF remains an important predictor of conversion to SR. Complications are rare and without long-term adverse effects.
Multispecies antbird societies in lowland forests of Surinam and Ecuador: stable membership and foraging differences

Flocks of insectivorous birds in the understory of lowland wet forest in Surinam and eastern Ecuador regularly included two species of antshrikes in the genus Thamnomanes (ardesiacus and caesius) and four species of antwrens in the genus Myrmotherula (in Surinam, axillaris, menetriesii, longipennis, and gutturalis; in Ecuador, the first two plus hauxwelli and ornata) (Formicariidae), as well as a number of other species particularly in the families Furnariidae and Dendrocolaptidae. Each flock included only a pair or occasionally a small group of each species. Although the individuals in a flock often spread over an area 30 m in diameter, the Myrmotherula, Thamnomanes and several other species moved cohesively through the forest. Each flock persisted throughout a day and, over periods of at least a week, recurred within the same largely exclusive range in the forest. The two Thamnomanes species had distinctive vocalizations that provided the primary signals for flock cohesion and alarm calls. Although most of the species of Myrmotherula had loud vocalizations, these were uttered too infrequently to contribute to flock cohesion and played no role in reactions to predators. In Central America, on the other hand, where Thamnomanes does not occur, M. fulviventris produces loud vocalizations, that resemble those of Thamnomanes, during disturbances to a flock. The species of Myrmotherula in each locality segregated ecologically in two dimensions, height of foraging above ground and preference for foraging in live or dead foliage. A shift in the foraging height of axillaris depending on the presence or absence of longipennis in the same flock suggested that competition for food has favoured ecological segregation of foraging height by these species. Thamnomanes–Myrmotherula flocks attain an unusual degree of cohesiveness and integration of foraging specialities in comparison with other mixed aggregations of animals.
Indole-3-Carbinol for recurrent respiratory papillomatosis: long-term results

We report the results of a clinical study using Indole-3-Carbinol (I3C) for the treatment of recurrent respiratory papillomatosis (RRP). I3C is abundant in cruciferous vegetables and has been shown to decrease papillomatous growth in cell cultures and be effective in an animal model of RRP. This is a prospective, open-label study design. Patients with RRP were enrolled from September 1996 to August 2001 and treated with I3C (adult dose of 200 mg PO BID). All patients underwent complete surgical removal and then started I3C. Further surgery was performed on an as-needed basis. Patients were categorized as having a complete, partial, or no response to I3C. Thirty-three patients treated with I3C were available for long-term follow-up (mean=4.8 years), whereas 12 patients were lost to follow-up. Eleven (33%) patients experienced remission of papillomatous growth and did not require surgery while on I3C. Ten (30%) patients had a reduction in papillomatous growth that resulted in less frequent surgery. Twelve patients (36%) had no clinical response. No patients experienced a worsening of their RRP. Of the 9 pediatric patients available, 1 experienced a complete response, 3 a partial response, and 5 had no response to I3C. Twelve patients with a positive response (partial or complete) to I3C are still taking I3C. Seven positive responders discontinued I3C, 3 of which have remained disease-free, whereas 4 continue to have RRP. No immediate or long-term side effects related to I3C were found. I3C has been found to be a successful treatment option for RRP. I3C's efficacy in pediatric patients merits further study.
Choline acetylase specificity in relation to biological function.

Abstract The specificity pattern of choline acetylase was tested with partially purified preparations, obtained from head ganglia of Squid, of a specific activity of about 40 to 80 μM of ester formed per mg protein per hour. The reaction mixture contained in addition to the enzyme only acyl derivatives of CoA and amino ethanols methylated with a varying number of methyl groups as substrates. The acetylation of choline was tested as a function of acetyl CoA, of choline and of enzyme concentration. The choline curves showed marked saturation corresponding to a Michaelis-Menten constant of about 2· IO −3 M . The acetyl CoA showed less saturation in the range tested; the data correspond to a Michaelis-Menten constant of the order of 5· IO −3 M . A striking differences was obtained in the acetylation of trimethyl, dimethyl and monomethyl ethanolamine. With the di- and monomethyl compounds the acetylation was only 8 and 2% respectively, compared to that of trimethyl aminoethanol. This strong distinction by the enzyme toward the 3rd methyl group becomes of great biological interest in view of comparably strong effects of the 3rd methyl group towards the other proteins of the acetylcholine systems. Loss of the 3rd methyl group leads to nearly complete loss of action upon the receptor protein which determines nerve membrane characteristics associated with such phenomena as ion permeability and electric potential. In the reactivation process of acetylcholinesterase inhibited by alkyl phosphates similar sharp differences between compounds with 2 and 3 methyl groups are observed in the interaction with the enzyme. In view of the chemically saturated nature of a quaternary group and its tetrahedral structure it is suggested that its unique action may be attributed to an alteration of the protein configuration so as to envelope the molecule. This appears necessary if the protein is to interact simultaneously with the three methyl groups and the chemical functional group of the molecule. Such change in configuration may be necessary for full function of the proteins. Among the acyl derivatives of CoA only propionyl CoA has a reactivity comparable to that of acetyl CoA. The enzyme does not mediate the reaction of butyryl CoA with choline, although the latter is bound by the enzyme even stronger than the acetyl CoA. This may have biological significance, since in contrast to propionyl CoA butyryl CoA is an intermediate of fatty acid metabolism and a ready formation of this choline ester may have undesirable effects.
An adaptive observation site selection strategy for road traffic data assimilation

Smartphones and other vehicular sensors equipped with GPS and wireless networking capabilities, are becoming ubiquitous in transportation systems. They provide us with opportunities to gather timely information about road traffic conditions, fuse (assimilate) it with traffic flow models to improve upon the accuracy of these models, and hence supply valuable information for real-time transportation decision making. Macroscopic traffic flow models are described by systems of partial differential equations (PDEs), which are usually only solved numerically. Adaptive moving mesh methods have shown promise in handling high variability of the spatio-temporal features (e.g. shocks and discontinuities) in model's solutions.We propose a novel low-overhead strategy to adaptively select observation sites in real time, by relying on information from the adaptive moving mesh of the numerical solver of the underlying PDEs. The idea is to place more of the limited observational resources to locations of higher variability in the numerical solution. We incorporate our strategy into a particle-filter based data assimilation framework, and compare it with the strategy of gathering and assimilating measurements from evenly spaced observation sites. We experimentally show that our strategy reduces the relative error by up to 53% in estimating vehicle density on a road during phantom jams and traffic jams due to bottlenecks.
A structure-based computational mutagenesis elucidates the spectrum of stability-activity relationships in proteins

Protein engineering experiments involving single amino acid substitutions are routinely implemented for the analysis of protein structure, stability, and function. The resulting change in just one of these characteristics relative to the native protein constitutes the focus of any single study, as is the case with predictive computational models developed for the same purpose. Other than investigations into stability-activity trade-offs specifically resulting from active site residue replacements in a few enzymes, a literature survey fails to reveal a comprehensive analysis of stability-activity relationships in proteins upon mutation. Here, we employ a computational mutagenesis for quantifying overall protein structural change upon mutation, which is applied to a dataset of 938 single residue replacements distributed at positions throughout twenty diverse proteins. These mutants are selected based on the availability of both experimental stability and activity change data, and their structural change data are used to characterize the full range of stability-activity relationships.
Effect of ferric nitrilotriacetate on rostral mesencephalic cells.

After murine fetal cells from the rostral mesencephalic tegmentum were isolated, prepared, and cultured; neuronal and glial cells in primary mixed cell cultures were exposed to ferric nitrilotriacetate (Fe-NTA) at varying concentrations. Studies were performed at 23 days in culture after 14 day exposure to Fe-NTA. In addition to morphologic studies, biochemical assays including specific [3H]flunitrazepam (FLU) binding, clonazepam (CLO)-displaceable [3H]-FLU binding, Ro5-4864-displaceable [3H]-FLU binding, [3H]dopamine (DA) uptake, [3H]haloperidol (HAL) binding, [3H]spiperone (SP) binding, glutamine synthetase activity (GS), and protein determinations were performed. The data demonstrate that chelated ferric iron has an adverse effect on these cells. The data also demonstrate that increasing concentrations of Fe-NTA resulted in massive neuronal dropout leaving the culture population virtually all glial; however, the specific binding of [3H]HAL and [3H]SP increased. There was a concomitant decrease in both glutamine synthetase activity and overall protein content. The mechanism of enhancement in the presence of Fe-NTA of [3H]HAL and [3H]SP binding is unknown and may be unique, but may be related to the known increase in D2 receptor ligand affinity in the presence of other multivalent cations (Ca2+ and Mg2+).
Quantitative gene analysis of methylation and expression (Q‐GAME) in fresh or fixed cells and tissues

Epigenetic regulation of gene expression by DNA methylation is a central mechanism governing the silencing of tumor suppressor genes in many forms of cancer. Current methods have not proven optimal for the quantitative analysis of DNA methylation and corresponding in situ protein expression within cells in small specimens like skin biopsies. We have overcome this limitation by combining and modifying several techniques: target cell enrichment, DNA micro-isolation, one-step denaturation/bisulphite conversion/in-column desulphonation, specially designed PCR amplification, pyrosequencing and multispectral image analysis. Using this approach optimized for small samples, we can quantify minor alterations in gene methylation and protein expression using minimal amounts of tissue. Comparative studies of fresh and processed cells showed that our method is valid for DNA in both fresh and formalin-fixed, paraffin-embedded specimens. We can measure the effects of DNA methylation inhibitors, administered in vitro or in vivo, on the promoter methylation and protein expression of selected genes in specific cells. This novel approach should prove useful for a wide variety of investigative and clinical applications in dermatology and other specialties where the collection of small, routinely processed biopsy specimens is common. We refer to this method as Q-GAME (quantitative gene analysis of methylation and expression).
Novel technique for control of mediastinal bleeding during thyroidectomy for substernal goiter.

Goiters are estimated to develop in approximately 5% of the population. By definition, for a goiter to be considered mediastinal, at least 50% of the thyroid tissue must be located substernally. Mediastinal goiters can, in turn, be classified as primary or secondary. Primary mediastinal goiters, which represent about 1% of all mediastinal goiters, arise from accessory (ectopic) thyroid parenchyma located in the chest. These goiters are mainly intrathoracic and do not have any connection to thyroid tissue in the neck. Their blood supply originates from intrathoracic vessels. Secondary mediastinal goiters constitute the majority of mediastinal goiters and arise from downward extension of cervical thyroid tissue along the fascial planes of the neck. These goiters derive their blood supply from the superior and inferior thyroid arteries. This migration along the path of least resistance is assisted by negative mediastinal pressure generated by inspiration and swallowing. Most mediastinal goiters can be removed via a cervical incision, but patients with recurrent goiters can require a median sternotomy because of the development of parasitic mediastinal vessels. In this article, we present the case of a patient with a secondary mediastinal goiter who developed bleeding after its removal via a cervical incision, and report on the use of a Foley catheter to control the same.
Unequal Exchange and the Rentier Economy

Detailed analysis of BEA methodology and data strongly suggests that U.S. GDP is overvalued on the output side. The ability to generate income without producing real value-added output is a key cha...
9 Effects of Erythropoietin on Respiratory Epithelial Cell Growth and Function.

Erythropoietin has a wide variety of nonhematopoietic effects in the body, including the regulation of important enzymatic activity in the pulmonary endothelium. If erythropoietin plays a role in lung vascular cell function, we hypothesized that it might play a similar role in respiratory epithelial cell function. We used the A549 cell, an immortal adenocarcinoma cell line that has features similar to Type II alveolar cells, to test the effect of erythropoietin (50 U/ml) on growth and ion transport activity. Erythropoietin increased total cell protein in monolayers of A549 cells by an average of 30 % (n = 6, control: 47+ 10 vs erythropoietin 62+ 3, mean+ SD, ph 0.05), an effect that was largely the result of an increase in cell number and not simply cell hypertrophy (n = 6, control: 1.5 million+ 0.4 vs erythropoietin 2.2 million+ 0.4, ph 0.05). To see if erythropoietin also modulated ion transport in these cells, we measured the accumulation of 22Na and efflux of 36Cl following a 24 h erythropoietin exposure in monolayer. Total sodium uptake was increased on average by 30% (n = 10, control: 214+ 128 nmol/mg protein vs erythropoietin 278+ 169, p < 0.05), an effect that was the result predominately of an increase in transport through amiloride-sensitive sodium channels (n = 10, control: 180+ 122 nmol/mg protein vs erythropoietin 238+ 159, p < 0.05), the sodium transport pathway linked to fluid removal in the distal airspace. In related studies we measured the effect of a 24 h exposure to erythropoietin on the rate of 36Cl efflux from these same cells. Chloride efflux activity is linked to fluid secretion into the lung lumen, an important respiratory epithelial cell function before birth. We found erythropoietin decreased 36Cl efflux on average by nearly 40% (n = 6, control: 3.6+ 1.1 nmol/mg protein/min vs erythropoietin 2.2+ 0.9, p < 0.05). These results suggest that erythropoietin might play a role in the growth and function of the respiratory epithelium of the distal lung. Because of the influence of erythropoietin on sodium and chloride transport, we speculate that erythropoietin might influence fluid clearance from the alveolar space.
Theoretical Characterization of the Reaction Intermediates in a Model of the Nickel−Iron Hydrogenase of Desulfovibrio gigas

The catalytic cycle for H2 oxidation in [NiFe] D. gigas hydrogenase has been investigated through density functional theory (DFT) calculations on a wide variety of redox and protonated structures of the active site model, (CO)(CN)2Fe(μ-SMe)2Ni(SMe)2. DFT calculations on a series of known LFe(CO)(CN)(L‘)n- (L = Cp or Cp*, L‘ = CN, CO, CNCH3; n = 0, 1, 2) complexes are used to calibrate the calculated CO bond distances with the measured IR stretching frequency. By combining this calibration curve with the energy and CO bond distance of the DFT calculations on the active site model and the experimental IR frequencies on the enzyme, the redox states and structures of active site species have been determined: Ni-B is a Ni(III)−Fe(II) species, Ni-SI(a) is a Ni(II)−Fe(II) species, Ni-SI(b) has a protonated terminal sulfur (Ni bound), Ni-R is a Ni(II)−Fe(II) dihydrogen complex with H2 bound at Fe, and Ni-C is a Ni(III)−Fe(II) species with an Fe−H−Ni bridge. The latter species returns to Ni-SI through a Ni(I)−Fe(...
Thermodynamically based analysis and synthesis of chemical process systems

A systematic procedure is introduced for computer aided analysis and multi-objective optimal synthesis of a chemical process system. Maximizing the second law efficiency, or minimizing the dissipation of the available energy (exergy), is one of the objectives of optimal synthesis. The structure of the computer program for implementing the procedure is described. The line code is used to represent material species throughout the program, including input and output. The program contains three major subroutines: thermodynamic property estimation, system analysis, and system synthesis. The use of the program is illustrated with several examples in the areas of energy resource conversion, energy conservation, and material processing. More specifically, the Portland cement production process, the CO2 acceptor process, and the methanation process are systematically analyzed. The formulation of an optimal synthesis of the methanation process is also presented.
Theoretical Study of Pulse-Frequency Modulation

In this paper, we study the pulse-frequency modulation method in pulse communication. We do not restrict ourselves to the case when the number of samples per period of our signal, as well as per unit time, is very large. Hence, the accuracy in reconstruction of the signal will depend not only on the number of sampling points per period, but also upon their distribution. We shall assume a fixed average pulse frequency (sampling rate), and will seek the maximal range of the signal frequency for which the corresponding periodic signal may be transmitted with acceptable accuracy. Thus, we are interested in a kind of threshold problem. It is our aim to consider pulse-frequency modulation independently of the circuits used to realize it, inasfar as this is consistent with lucidity of presentation. In Sections 12, 15, 16, and 17, we study in detail the behavior of sampling in case the relative frequency v (the ratio of the signal frequency to the pulse frequency) falls into the ranges (0.4855, 0.51625), (0.33599, 0.33863), (0.6450, 0.6626), and (0.402645, 0.403030), respectively. This information supplies the reason for the limitation of the useful range of the relative frequency spectrum. Because of the extreme nonlinearity of pulse-frequency modulation, we cannot deduce the behavior of the general periodic signal from the behavior of its sinusoidal components, but we have to apply methods described in this paper directly to the particular wave form studied. This is illustrated by the example in the Appendix.
A SPATIAL ECONOMETRIC STAR MODEL WITH AN APPLICATION TO U.S. COUNTY ECONOMIC GROWTH, 1969–2003

Spatial regression models incorporating non-stationarity in the regression coefficients are popular. We propose a spatial variant of the Smooth Transition AutoRegressive (STAR) model that is more parsimonious than commonly used approaches and endogenously determines the extent of spatial parameter variation. Uncomplicated estimation and inference procedures are demonstrated using a neoclassical convergence model for United States counties.
EFFECT OF FOOD AVAILABILITY ON RATES OF LOSS OF 45 CALCIUM FROM HYPHANTRIA CUNEA (LEPIDOPTERA: ARCTIIDAE)

Final instar larvae of fall webworms, Hyphantria cunea (Drury), were labelled to equilibrium levels on persimmon leaves containing 45 Ca. Loss rates of 45 Ca from the larvae were followed in the laboratory after either feeding larvae on unlabelled leaves, or starving other larvae.Initial loss-rate characteristics were different in the two feeding treatments, but biological half-lives were not significantly changed. Feeding shifts the time at which the lower loss-rate comes into effect.