cssi/SciSciGPT-SciSciNet huggingface dataset:
A study of the vibrational behavior of imidazole by the ab initio gradient method

Abstract The complete harmonic vibrational force field of imidazole has been computed at the Hartree—Fock level using the 4–21 basis set of Gaussian orbitals. The harmonic constants were scaled by using scale factors previously derived by fitting the computed force field of benzene to the observed benzene vibrational spectrum. The resulting scaled force field was then used to predict the vibrational spectrum of imidazole. The NH wagging and NH stretching frequencies, which have no counterpart in benzene, were poorly predicted, but the mean deviation between experiment and prediction was only 9 cm−1 for the other in-plane (A′) vibrations and 27 cm−1 for the out-of-plane (A″) vibrations. In order to fit the NH modes and to obtain a better fit for the out-of-plane vibrations, a new set of scale factors, some of which turned out to be identical with those from benzene, was derived by fitting the computed spectrum of imidazole to the observed spectrum. This new set of scale factors was used to predict the vibrational spectra of several deuterated forms of imidazole (−1D, −3D, and −4D). The imidazole scale factors are presumably more accurate in scaling computed spectra of other 5-membered heterocyclic ring compounds. Dipole moment derivatives were also calculated and used to predict infrared intensities which are compared with experimental values. A few uncertainties in the experimental assignment of the imidazole spectrum can be clarified.
Time course of syringomyelia resolution following decompression of Chiari malformation Type I

Object To better understand syrinx pathophysiology, the authors performed a prospective study in which they used findings from serial clinical and magnetic resonance (MR) imaging examinations performed before and after craniocervical decompression to establish the time course of syrinx narrowing. Methods Serial clinical examinations and cervical MR imaging were performed in 29 consecutive patients with Chiari malformation Type I (CM-I) and syringomyelia before surgery, 1 week, and 3–6 months after surgery, and then annually. Time to narrowing of the syrinx (> 50% decrease in maximal anteroposterior diameter) following surgery was calculated using the Kaplan–Meier method. Results All syringes decreased in diameter and length (number of segments) on MR images at 3–6 months, 1 year, and 2 years or later. The syrinx diameter decreased from 6.9 ± 2.1 mm (mean ± standard deviation) preoperatively to < 1.5 mm at last evaluation (p < 0.0001). The median time to syrinx narrowing was 3.6 months following CM-I decom...
Using CFD to understand how flow patterns affect retention of cell-sized particles in a tubular bowl centrifuge

Sigma theory is commonly used to predict the conditions that result in half of the entering particles being retained within a continuous-flow centrifuge. In this research, a 2D computational fluid dynamics (CFD) model of flow through a tubular bowl centrifuge (Sharples, 5 cm radius) was developed with Fluent software. A volume-of-fluid (VOF) approach was used for most of the simulations to track the motion of the liquid and gas phases, because the location of the gas/liquid interface depends on the centrifuge operating conditions. The CFD results indicate that the assumptions of plug flow and rigid body motion, which are fundamental assumptions of Sigma theory, were not valid for the conditions tested (700 < Rez < 3500 and 1000 < speed (rpm) < 3000). The average interfacial axial velocities (Viz) were 6−18 times greater than the plug-flow velocity (Vpf), and the average interfacial swirl velocities (Viθ) were 0.12−0.41 of that corresponding to rigid body motion (Vrbm). Despite these differences, the CFD r...
On the electronic structures of the gold tetramer clusters

Ab initio second order many body perturbation theory with scalar relativistic pseudopotentials have been used to determine the global minimum energy structures of the neutral, cationic and anionic gold tetramer clusters. The rhombic structure is found to be the most stable structure for all three charge states of the tetramer. The adiabatic ionization potential and the electron affinity are predicted to be 190.13 and 59.67 kcal/mol, respectively. Results are compared, wherever possible, with published data in the literature.
Tax structure and state economic growth during the Great Recession

Abstract Concern about the effect of taxes on economic growth and development in the United States is longstanding. While most studies are concerned with the growth impacts of tax burden, marginal rates, or the impact of a particular tax, there are few works that examine the impact of tax structure in the way it is defined in this work. Here, tax structure is defined as the shares of revenue collected by various taxes. Using a pool of data on the 50 states between 2004 and 2010, this paper explores the relationship between state and local tax structure and growth of real per-capita GDP through the Great Recession centered in 2008. The results are used to generate estimates of the growth impacts of revenue neutral changes in tax shares.
Restless behavior increases over time, but not with compressibility of the flooring surface, during forced standing at the feed bunk

Abstract Interest in the use of rubber flooring in freestall barns has increased, but little is known about which design features of these surfaces are important for cattle. In 2 experiments, we evaluated how the type and compressibility of the flooring surface in front of the feed bunk influenced the behavioral response to 4 h of forced standing after morning milking. Two flooring types were compared: rubber and concrete. Rubber was tested at 3 levels of compressibility: 2, 4, and 35 times as compressible as concrete. Four hours of forced standing was evaluated because it mimicked conditions that can occur on dairies, particularly when waiting for artificial insemination or veterinary treatment. The effects of cow weight and hoof surface area, gait score, and hoof health on the response to treatment were evaluated. Restless behavior, as measured by number of steps, almost doubled over the 4 h of forced standing, regardless of flooring material. Cows lay down, on average, within 5 min after access to the lying area was provided. These results indicate that the 4 h of forced standing was uncomfortable. No differences in restless behavior were observed in association with the type or compressibility of the flooring surface in front of the feed bunk. Cow size, hoof health, or gait score did not consistently explain the response to the flooring treatments or stepping rate, although these populations of animals were generally healthy. It is unclear if comfort did not differ between the flooring options tested during 4 h of forced standing or if alterative methodology, such as measuring more subtle shifts in weight, is required to assess design features of rubber flooring.
Vapor-liquid equilibrium in mixtures of cyclohexane + benzene, + octene-1, + m-xylene, and + n-heptane

Abstract Vapor-liquid equilibrium has been determined for four binary hydrocarbon mixtures: cyclohexane + benzene, + m -xylene, + n -heptane, and + octene-1. Isothermal variation of the saturation pressure with liquid-phase composition was determined experimentally in a static apparatus over the entire composition range. The composition of the equilibrium vapor phase is obtained by calculation with Barker's method using the Redlich-Kister equation for the activity coefficients.
An Investigation of Asphalt Durability: Relationships Between Ductility and Rheological Properties for Unmodified Asphalts

Literature reports indicate that the ductility of binders recovered from asphalt pavements correlate with cracking failure. However, ductility measurement is a time and material consuming process, ...
711 REGIONAL CHROMOSOMAL ASSIGNMENT OF THE STRUCTURAL GENE FOR HUMAN ACID β-GLUCOSIDASE

Human acid β-glucosidase (GBA), the lysosomal enzyme deficient in Gaucher disease, has been mapped to chromosome 1 using somatic cell hybridization techniques. Antibody against purified human GBA was raised in Balb/C mice and a sensitive double antibody immunoprecipitation assay was developed to detect human GBA activity in mouse RAG X human fibroblast hybrids. The mouse anti-human GBA antibody was specific for human GBA and no cross-reactivity between mouse β-glucosidase or several other human enzymes, including neutral β-glucosidase could be detected. Fifty-two primary, secondary and tertiary hybrid lines, derived from three separate fusion experiments, were analyzed for human GBA and enzyme markers for each human chromosome. There was 100% correlation between the presence of human GBA and the presence of human chromosome 1 as determined by cytogenetic and chromosome 1 enzymatic marker (phosphoglucomutase 1 and fumurate hydratase) analyses. All other human chromosomes segregated independently of human GBA. The structural locus for human GBA was further defined to the region 1p11 → lqter by using a RAG X human fibroblast line which carried a mouse-human rearrangement involving human chromosome 1.
A shock tube study of the CH2O + NO2 reaction at high temperatures

The reaction of CH 2 O with NO 2 has been studied with a shock tube equipped with two stabilized cw CO lasers. The production of CO, NO, and H 2 O has been monitored with the CO lasers in the temperature range of 1140-1650 K using three different Ar-diluted CH 2 O-NO 2 mixtures. Kinetic modeling and sensitivity analysis of the observed CO, NO, and H 2 O production profiles over the entire range of reaction conditions employed indicate that the bimolecular metathetical reaction, NO 2 +CH 2 O→HONO+CHO (1) affects most strongly the yields of these products. Combination of the kinetically modeled values of k 1 with those obtained recently from a low temperature pyrolytic study, ref. [8], leads to k 1 =8.02×10 2 T 2.77 e −6910/T cm 3 /mol sec for the broad temperature range of 300-2000 K
Teaching Consonants to Profoundly Hearing-Impaired Speakers Using Palatometry

Five profoundly hearing-impaired children were taught the consonants /t,d,k,g,s,z∫/ using palatometry. Changes in linguapalatal contact patterns and listener perceptions showed significant improvement in the place and manner of consonants produced by all subjects. Velar stops were as easily and accurately learned as alveolar stops. Distinctive sibilants were also found by the end of training. Sounds not previously present in a subject’s phonetic repetoire were learned more accurately than those present but inaccurate prior to therapy. Voicing errors persisted. Two of the subjects showed evidence of newly established, unsolicited coarticulated movements. The results indicated that visual articulatory modeling and feedback of linguapalatal contact patterns is an effective means of teaching consonants and improving speech intelligibility.
LYSINE DEFICIENCY AND HOST RESISTANCE TO ANTHRAX

1. Lysine deficiency has been produced in rats by placing the weanling animals on an experimental diet in which gluten replaced the casein of the control diet. Both diets were complete in all other known requirements. 2. The resistance of the deficient animals to a subcutaneous challenge of several concentrations of B. anthracis spores, was decreased. Deaths occurred within 2 days post inoculation. 3. When lysine was added to the gluten diet to bring the total concentration to that of the control diet, the growth rate of the animals was maintained but a decrease in resistance remained, although not as great as on the gluten diet. 4. Changes in the tissues associated with lysine deficiency are reported. 5. It is not unreasonable to state that within the time frame of our experiments, the decreased ability of the RES of the host to clear the invading organism from the tissues and subsequently to break down the organism is a major factor of the decreased resistance of the lysine-deficient rats to anthrax.
State budget sizes and the marginal productivity of governors: An extension

An improved specification of the model used by C-T reveals that governors in those states where constitutional methods are used to determine gubernatorial compensation may have greater incentives to expand their respective state budget and, in doing so, increase their pay. The additional evidence offered in this paper suggests that such uses of discretionary power may be negligible or effectively blocked by competing groups. Thus, employing a more rigorous testing of the applicability of marginal productivity theory to the determination of gubernatiorial compensation supports the C-T contention that governors' pay may be determined in ways quite similar to those of comparable private factor markets, viz., by the competitive process.
Development of an animal model for ovotoxicity using 4-vinylcyclohexene: a case study.

BACKGROUND The occupational chemical 4-vinylcyclohexene (VCH) has been shown to cause destruction of small pre-antral follicles in ovaries of mice. Further, its monoepoxide metabolites, 1,2-VCH epoxide, 7,8-VCH epoxide, and the diepoxide, VCD, have been shown to cause pre-antral follicle loss in rats as well as mice. Chemicals that destroy small pre-antral follicles are of concern to women because exposure can result in premature ovarian failure (early menopause). METHODS Studies working with these chemicals over the past decade have determined a number of aspects of the mechanism(s) of small pre-antral destruction, and a variety of questions have been answered. RESULTS Specifically, it has been determined that the diepoxide (VCD) is the bioactive form and it directly targets the ovary in mice and rats. Mice are more susceptible to VCH than rats because they are capable of its metabolic bioactivation. Follicle destruction by VCD is selective for primordial and primary follicles. Mechanistic studies in rats have determined that VCD causes ovotoxicity by accelerating the natural process of atresia (apoptosis) and this requires repeated exposures. Pro-apoptotic signaling events in the Bcl-2 and mitogen activated protein kinase families have been shown to be selectively activated in fractions of small pre-antral follicles (targets for VCD). Finally, a whole ovarian culture system using neonatal mouse and rat ovaries has been developed to expand the potential for more in depth investigations into ovotoxicity caused by VCD. CONCLUSIONS This article provides an overview of the questions asked and the approaches taken in studying VCH and VCD to support these conclusions. Birth Defects Res (Part B), 2007. © 2007 Wiley-Liss, Inc.
Effect of spectral emissivity on single broadband MWIR image simulation

The question of whether it is always appropriate to assume in the generation of synthetic, single broadband midwave infrared (MWIR) imagery that the emissivities of scenery objects are constants with respect to wavelength is addressed. In the radiometric measurement equation, the detector signal due to the image plane irradiance within a finite waveband is proportional to the integral of the detector spectral responsivity times the scene radiance, and the scene radiance is the directional spectral emissivity of the scene times the spectral radiance of a blackbody at the same temperature. Using the spectral emissivity data of a set of commonly encountered scenery materials and different temperatures, single broadband MWIR image signals from idealized thermal and InSb-type photon detectors were computed using the measurement equation with spectral emissivity and detector responsivity and with several emissivity and detector responsivity approximations for comparison. The results show a strong correlation between the relative variation, or fractional standard deviation, of the average MWIR emissivity and the error in the emissivity/responsivity approximation results relative to the spectral emissivity/responsivity results.
Measurements of N2O, CF2Cl2, CFCI3, CH3CCl3, CCl4, and CH3Cl in the troposphere and lower stratosphere over North Amrica.

Samples of tropospheric and stratospheric air were collected on aircraft flights between October 4 and October 13, 1976. The region of the atmosphere surveyed was over the North American continent (approximately 18°N to 65°N latitude). Samples were obtained at heights ranging from about 3, 000ft. to 45, 000ft. Measurements of N2O, CF2Cl2, CFCl3, CH3CCl3, and CCl4 were made by GC/EC techniques, and of CH3Cl by GC/MS. The latitudinal and height profiles of these trace gases are reported in this paper. Calculations based on these measurements yield the following average tropospheric concentrations: [N2O]=(330±2) ppb v, [CF2Cl2]=(236±7) ppt v, [CFCl3]=(140±5) ppt v, [CH3CCl3]=(145±25) ppt v, and [CCl4]=(134±9) ppt v (where the ± values are the standard deviations). The N2O mixing ratio decreases only slightly in the lower stratosphere. CF2Cl2 and CFCl3 mixing ratios decrease by about 10% and 15% respectively, within 4km above the tropopause. CCl4 mixing ratio declines by about 50% within 4km above the tropopause. CH3CCl3 mixing ratios also show a sharp decline above the tropopause, similar to that of CCl4. CH3Cl on the other hand displays almost no change in mixing ratio between the free troposphere and the lower stratosphere.
Microbial carbohydrate depolymerization by antigen-presenting cells: Deamination prior to presentation by the MHCII pathway

After uptake by the endosome of an antigen-presenting cell (APC), exogenous proteins are known to be degraded into peptides by protease digestion. Here, we report the mechanism by which pure carbohydrates can be depolymerized within APC endosomes/lysosomes by nitric oxide (NO)-derived reactive nitrogen species (RNSs) and/or superoxide-derived reactive oxygen species (ROSs). Earlier studies showed that depolymerization of polysaccharide A (PSA) from Bacteroides fragilis in the endosome depends on the APC's having an intact inducible nitric oxide synthase (iNOS) gene; the chemical mechanism underlying depolymerization of a carbohydrate within the endosome/lysosome is described here. Examining the ability of the major RNSs to degrade PSA, we determined that deamination is the predominant mechanism for PSA processing in APCs and is a required step in PSA presentation to CD4(+) T cells by MHCII molecules. Structural characterization of the NO-derived product PSA-NO indicates that partial deaminative depolymerization does not alter the zwitterionic nature of PSA. Unlike native PSA, PSA-NO is presented by iNOS-deficient APCs to induce CD4(+) T cell proliferation. Furthermore, metabolically active APCs are required for PSA-NO presentation. In contrast to PSA degradation by RNSs, dextran depolymerization in the endosome depends on ROSs, including hydrogen peroxide- and superoxide-derived ROSs. This study provides evidence that MHCII pathway-mediated carbohydrate antigen processing in APCs is achieved by chemical reactions. RNSs and ROSs may be involved in the presentation of glycopeptides by MHC molecules via the processing of other carbohydrate-containing antigens, such as bacterial or viral glycoproteins or glycoconjugate vaccines.
IDENTIFICATION OF THE SITE IN THE SUBSTANCE P (NK-1) RECEPTOR FOR MODULATION OF PEPTIDE BINDING BY SULFHYDRYL REAGENTS

Abstract Substance P (SP) is a peptide neurotransmitter that is involved in multiple responses in both the central and the peripheral nervous systems through a G-protein-coupled receptor. The primary structure of the rat SP receptor contains a number of conserved cysteine residues. To localize and identify the cysteine residues that participate in receptor binding, intact Chinese hamster ovary cells expressing the SP receptor were treated with various sulfhydryl reagents and the effect of these reagents on radioiodinated SP binding affinity and dissociation rate was determined. We used a series of amphiphilic maleimide derivatives in which the reactive maleimide group penetrates to different depths within the plane of membrane. Only the maleimide derivatives with intermediate chain lengths modified receptor binding properties, indicating that the reactive sulfhydryl group is located within a transmembrane domain of the receptor close (within 1.7 nm) to the extracellular border. Since peptide binding to a mutant receptor C199S, in which Cys-199 was replaced by a serine, was found to be insensitive to modulation by sulfhydryl reagents, this reactive sulfhydryl group is on Cys-199 of the receptor. Receptor occupancy by SP protects Cys-199 from modification and thus this residue is either located at or conformationally linked to the SP binding site.
Theory of pulse instabilities in electrophysiological models of excitable tissues

Abstract We develop a theoretical framework which allows, starting from multi-variable electrophysiological PDE models, to make ab initio quantitative predictions of the instability threshold and nonlinear dynamics of a pulse propagating in a ring of excitable tissue. This framework is based on the reduction of the PDE models to a single-front free-boundary problem in which the fast membrane-current variables are eliminated and only the dynamics of the slow relevant ones are retained. The solution of this free-boundary problem is in turn well approximated by a simple discrete map whose dimension D is equal to the number of slow membrane-current variables. This framework is applied to the Noble (D = 1) and Beeler-Reuter model (D = 3) of cardiac tissue and found to yield results in reasonably good quantitative agreement with PDE simulations. For the Beeler- Reuter model, the minimum period of stable propagation is found to depend sensitively on the dynamics of the calcium channel in a way which, together with the two-dimensional numerical simulations of Courtemanche and Winfree (Int. J. Bifurcation and Chaos 1 (1991) 431), strongly suggests that spiral breakup in this model occurs as a result of electrical alternans.
Racial democracy and the black metropolis: housing policy in postwar Chicago

Racial democracy and the black metropolis: housing policy in postwar Chicago, by Preston H. Smith II, Minneapolis, University of Minnesota Press, 2012, 433 pp., US$27.50 (paperback) Preston H. Smit...
Chronological framework for the deglaciation of the Lake Michigan lobe of the Laurentide Ice Sheet from ice-walled lake deposits

A revised chronological framework for the deglaciation of the Lake Michigan lobe of the south-central Laurentide Ice Sheet is presented based on radiocarbon ages of plant macrofossils archived in the sediments of low-relief ice-walled lakes. We analyze the precision and accuracy of 15 AMS 14 C ages of plant macrofossils obtained from a single ice-walled lake deposit. The semi- circular basin is about 0.72 km wide and formed of a 4- to 16-m-thick succession of loess and lacustrine sediment inset into till. The assayed material was leaves, buds and stems of Salix herbacea (snowbed willow). The pooled mean of three ages from the basal lag facies was 18 270 � 50 14 C a BP (21 810 cal. a BP), an age that approximates the switch from active ice to stagnating conditions. The pooled mean of four ages for the youngest fossil-bearing horizon was 17 770 � 40 14 C a BP (21 180 cal. a BP). Material yielding the oldest and youngest ages may be obtained from sediment cores located at any place within the landform. Based on the estimated settling times of overlying barren, rhythmically bedded sand and silt, the lacustrine environment persisted for about 50 more years. At a 67% confidence level, the dated part of the ice-walled lake succession persisted for between 210 and 860 cal. a (modal value: 610 cal. a). The deglacial age of five moraines or morainal complexes formed by the fluctuating margin of the Lake Michigan lobe have been assessed using this method. There is no overlap of time intervals documenting when ice-walled lakes persisted on these landforms. The rapid readvances of the lobe during deglaciation after the last glacial maximum probably occurred at some point between the periods of ice-walled lake sedimentation. Copyright # 2011 John Wiley & Sons, Ltd.
On surface waves crossing a step with horizontal shear

On considere la refraction et la reflexion partielle des ondes de gravite en surface sur une discontinuite de profondeur, de vitesse ou des deux a la fois. Solutions approchees
Fiber optic sensor for measurement of pressure fluctuations at high temperatures

A fiber-optic sensor, based on the principle of the fiber-optic lever, is described which features small size, extended bandwidth, and capability to operate at high temperatures, as required for measurements in hypersonic flow. The principle of operation, design features peculiar to the intended application, and expected performance at high temperatures are described. >
A Method for Compact Image Representation Using Sparse Matrix and Tensor Projections Onto Exemplar Orthonormal Bases

We present a new method for compact representation of large image datasets. Our method is based on treating small patches from a 2-D image as matrices as opposed to the conventional vectorial representation, and encoding these patches as sparse projections onto a set of exemplar orthonormal bases, which are learned a priori from a training set. The end result is a low-error, highly compact image/patch representation that has significant theoretical merits and compares favorably with existing techniques (including JPEG) on experiments involving the compression of ORL and Yale face databases, as well as a database of miscellaneous natural images. In the context of learning multiple orthonormal bases, we show the easy tunability of our method to efficiently represent patches of different complexities. Furthermore, we show that our method is extensible in a theoretically sound manner to higher-order matrices (?tensors?). We demonstrate applications of this theory to compression of well-known color image datasets such as the GaTech and CMU-PIE face databases and show performance competitive with JPEG. Lastly, we also analyze the effect of image noise on the performance of our compression schemes.
The Significance of Hypothermia in Preserving Ischemic Myocardium

The clinical use of mild hypothermia to preserve ischemic cardiac and cerebral tissue continues to grow in popularity. This is a result of the known fact that hypothermia reduces myocardial oxygen demands more than any other intervention. The Advanced Life Support (ALS) Task Force of the International Liaison Committee on Resuscitation (ILCOR) made the following recommendations a year ago, in October 2002: "Unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest should be cooled to 32 degrees C to 34 degrees C for 12 to 24 hours when the initial rhythm was VF," or in-hospital even when arrest is due to other rhythms. Therapeutic use of hypothermia is in progress.
DEMOCRATIC POSTURING AND PECULIAR LIBERALISM: LEO STRAUSS, HIS STUDENTS, AND AMERICA

The argument in this essay is that far from being the Machiavellian/Platonists as their harsher critics have described them, Strauss and his students are in fact defenders of a particular kind of liberal-democracy. Unfortunately, however, the Straussian theorization of such a regime is both theoretically flawed, and practically impotent, especially in the American liberal context, leaving both him and his students with what could perhaps be called a “Calhoun problem.”
Schedules of Reinforcement at 50: A Retrospective Appreciation

Published just over a half century ago, Schedules of Reinforcement (SOR) (Ferster & Skinner, 1957) marked the seminal empirical contribution of the book’s second author and ushered in an era of research on behavior–environment relationships. This article traces the origins of both the methods and the data presented in SOR, and its legacy within experimental psychology. The operant methodology outlined in SOR revolutionized the study of behavior pharmacology and early investigations of choice behavior. More recently, schedules have been used to examine microeconomic behavior, gambling, memory, and contingency detection and causal reasoning in infants, children, and adults. Implications of schedules research for the psychology curriculum are also discussed. A half century has come and gone since the publication of Schedules of Reinforcement (Ferster & Skinner, 1957), a landmark work in experimental psycholog y, and inarg uably Sk in ner’s most substantive empirical contribution to a science of behavior. The book introduced psychologists to an innovative methodology for studying the moment-to-moment dynamics of behavior–environment interactions, presented volumes of realtime data exhibiting an orderliness nearly unprecedented in psychology, and established the research agenda of the science Skinner termed the experimental analysis of behavior. Although he drew sharp and abundant criticism for his forays into social theorizing, Skinner’s experimental work was frequently recognized, even by those not sharing his epistemology, as a rigorous and important development in behavioral science, as attested to by numerous awards, including the American Psychological Association’s (APA’s) Distinguished Scientific Contribution Award (APA, 1958) and the National Medal of Science (APA, 1969). Skinner has frequently been acknowledged as among psychology’s most eminent figures (Haggbloom et al., 2002). Unfortunately, much of his reputation, among both psychologists and laypersons, stems largely from his writings on freedom, dignity, autonomous man, the limitations of cognitive Correspondence concerning this article should be addressed to David L. Morgan, PhD, School
Dynamics of the Cell Cycle: Checkpoints, Sizers, and Timers

We have developed a generic mathematical model of a cell cycle signaling network in higher eukaryotes that can be used to simulate both the G1/S and G2/M transitions. In our model, the positive feedback facilitated by CDC25 and wee1 causes bistability in cyclin-dependent kinase activity, whereas the negative feedback facilitated by SKP2 or anaphase-promoting-complex turns this bistable behavior into limit cycle behavior. The cell cycle checkpoint is a Hopf bifurcation point. These behaviors are coordinated by growth and division to maintain normal cell cycle and size homeostasis. This model successfully reproduces sizer, timer, and the restriction point features of the eukaryotic cell cycle, in addition to other experimental findings.
Biochemical, Molecular, and Genetic Analyses of the Acetone Carboxylases from Xanthobacter autotrophicus Strain Py2 and Rhodobacter capsulatus Strain B10

Acetone carboxylase is the key enzyme of bacterial acetone metabolism, catalyzing the condensation of acetone and CO 2 to form acetoacetate. In this study, the acetone carboxylase of the purple nonsulfur photosynthetic bacterium Rhodobacter capsulatus was purified to homogeneity and compared to that of Xanthobacter autotrophicus strain Py2, the only other organism from which an acetone carboxylase has been purified. The biochemical properties of the enzymes were virtually indistinguishable, with identical subunit compositions (α 2 β 2 γ 2 multimers of 85-, 78-, and 20-kDa subunits), reaction stoichiometries (CH 3 COCH 3 + CO 2 + ATP→CH 3 COCH 2 COO − + H + + AMP + 2P i ), and kinetic properties ( K m for acetone, 8 μM; k cat = 45 min −1 ). Both enzymes were expressed to high levels (17 to 25% of soluble protein) in cells grown with acetone as the carbon source but were not present at detectable levels in cells grown with other carbon sources. The genes encoding the acetone carboxylase subunits were identified by transposon mutagenesis of X. autotrophicus and sequence analysis of the R. capsulatus genome and were found to be clustered in similar operons consisting of the genes acxA (β subunit), acxB (α subunit), and acxC (γ subunit). Transposon mutagenesis of X. autotrophicus revealed a requirement of σ 54 and a σ 54 -dependent transcriptional activator (AcxR) for acetone-dependent growth and acetone carboxylase gene expression. A potential σ 54 -dependent promoter 122 bp upstream of X. autotrophicus acxABC was identified. An AcxR gene homolog was identified 127 bp upstream of acxA in R. capsulatus , but this activator lacked key features of σ 54 -dependent activators, and the associated acxABC lacked an apparent σ 54 -dependent promoter, suggesting that σ 54 is not required for expression of acxABC in R. capsulatus. These studies reveal a conserved strategy of ATP-dependent acetone carboxylation and the involvement of transcriptional enhancers in acetone carboxylase gene expression in gram-negative acetone-utilizing bacteria.
Thermal Inkjet Application in the Preparation of Oral Dosage Forms: Dispensing of Prednisolone Solutions and Polymorphic Characterization by Solid-State Spectroscopic Techniques

The utility of thermal inkjet (TIJ) technology for preparing solid dosage forms of drugs was examined. Solutions of prednisolone in a solvent mixture of ethanol, water, and glycerol (80/17/3 by volume) were dispensed onto poly(tetrafluoroethylene)-coated fiberglass films using TIJ cartridges and a personal printer and using a micropipette for comparison. The post-dried, TIJ-dispensed samples were shown to contain a mixture of prednisolone Forms I and III based on PXRD analyses that were confirmed by Raman analyses. The starting commercial material was determined to be Form I. Samples prepared by dispensing the solution from a micropipette initially showed only Form I; subsequent Raman mapping of these samples revealed the presence of two polymorphs. Raman mapping of the TIJ-dispensed samples also showed both polymorphs. The results indicate that the solvent mixture used in the dispensing solution combined with the thermal treatment of the samples after dispensing were likely the primary reason for the generation of the two polymorphs. The advantages of using a multidisciplinary approach to characterize drug delivery systems are demonstrated using solid state mapping techniques. Both PXRD and Raman spectroscopy were needed to fully characterize the samples. Finally, this report clarifies prednisolone's polymorphic nomenclature existent in the scientific literature. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2619–2636, 2008
Sublethal effects of nitrite on eastern tiger salamander (Ambystoma tigrinum tigrinum) and wood frog (Rana sylvatica) embryos and larvae: implications for field populations

Ephemeral pools, which can have high animal biomass and low dissolved oxygen, may be prone to nitrite accumulation. As such, it is important to understand how exposure to nitrite might affect development and growth of amphibians that breed in these ephemeral pools. Wood frog (Rana sylvatica) and eastern tiger salamander (Ambystoma tigrinum tigrinum) embryos and tadpoles and young larvae were exposed to elevated concentrations of nitrite derived from sodium nitrite: 0, 0.3, 0.6, 1.2, 2.1, 4.6, and 6.1 mg l−1 NO2–N. Increasing nitrite exposure slowed embryonic and larval development in both the eastern tiger salamander and the wood frog, reduced growth in tiger salamander embryos and larvae, and delayed metamorphosis in the wood frog. At concentrations less than 2 mg l−1 NO2–N nitrite delayed hatching, and at concentrations above 2 mg l−1 time to hatching decreased causing more individuals to hatch at less developed stages. Nitrite also increased asynchrony in tiger salamander hatching. The sublethal effects of nitrite on amphibian development, growth and hatching could have serious repercussions on amphibian fitness in ephemeral environments. Potential increases in mortality on field populations caused by sublethal effects of nitrite are discussed.
Multiphase Fluid-Loss Properties and Return Permeability of Energized Fracturing Fluids

With the growing interest in low-permeability gas plays, foam fracturing fluids are now well established as a viable alternative to traditional fracturing fluids. Present practices in energized fracturing treatments remain, nonetheless, rudimentary in comparison to other fracturing-fluid technologies because of our limited understanding of multiphase fluid-loss and phase behavior occurring in these complex fluids. This paper assesses the fluid-loss benefits introduced by energizing the fracturing fluid. A new laboratory apparatus has been specifically designed and built for measuring the leakoff rates for both gas and liquid phases under dynamic fluid-loss conditions. This paper provides experimental leakoff results for linear guar gels and for N2/guar foambased fracturing fluids under a wide range of fracturing conditions. In particular, the effects of the rock permeability, the foam quality, and the pressure drop are investigated. Analysis of dynamic leakoff data provides an understanding of the complex mechanisms of viscous invasion and filter-cake formation occurring at the pore scale. This study presents data supporting the superior fluid-loss behavior of foams, which exhibit minor liquid invasion and limited damage. It also shows direct measurements of the ability of the gas component to leakoff into the invaded zone, thereby increasing the gas saturation around the fracture and enhancing the gas productivity during flowback. Our conclusions not only confirm but add to the findings of McGowen and Vitthal (1996a, b) for linear gels and the findings of Harris (1985) for nitrogen foams.
Widowhood and the end of spousal care-giving : relief or wear and tear ?

This paper analyses the impact of spousal care-giving on survivors’ depressive symptoms six months into widowhood, and examines the applicability of a ‘ relief model ’ of spousal adjustment during bereavement. We examine several aspects of the care-giving situation, including care-giver stress, care-giving demands, and type and duration of care and how these affect survivors’ depressive symptomatology. The sample is drawn from two waves of the Changing Lives of Older Couples (CLOC) survey, which was conducted in the United States in the Detroit Metropolitan Area, Michigan. The first wave of data was collected from couples and the second from the surviving spouse six months after the death of the partner. We use multiple regression analysis to examine the effects of key variables on depressive symptoms six months into widowhood, controlling for various demographic characteristics and personal circumstances. The results demonstrate that the duration of care-giving is the most influential predictor of survivors’ depressive symptoms six months after the death. Indeed, long-term care-givers experience greater relief than both non-caregivers and short-term care-givers, as the predicted probabilities indicate. The results lead us to emphasise that care-giving and spousal bereavement should be studied as related processes rather than distinct phenomena. Indeed, relief from a chronically stressful care situation may actually ameliorate the negative effect of spousal loss for survivors.
Studying Complexity of Model-based Clustering

Cluster analysis is a popular statistics and computer science technique commonly used in various areas of research. In this article, we investigate factors that can influence clustering performance in the model-based clustering framework. The four factors considered are the level of overlap, number of clusters, number of dimensions, and sample size. Through a comprehensive simulation study, we investigate model-based clustering in different settings. As a measure of clustering performance, we employ three popular classification indices capable of reflecting the degree of agreement in two partitioning vectors, thus making the comparison between the true and estimated classification vectors possible. In addition to studying clustering complexity, the performance of the three classification measures is evaluated.
Does alpha-melanocyte-stimulating hormone from the pars intermedia regulate suckling-induced prolactin release? Supportive evidence from morphological and functional studies.

Recent evidence suggests that substances derived from the hypophyseal intermediate lobe (IL) play a crucial role in the regulation of suckling-induced PRL secretion. The purpose of the present study was to explore this possibility further by determining whether the suckling stimulus acutely increases the secretory activity of the IL and whether alpha MSH, a major secretory product of the IL, plays a specific role in suckling-induced PRL release. Light microscopic morphometric analysis of serial pituitary sections obtained from lactating rats revealed that as little as 1 min of suckling caused a significant increase in the proportion of the IL that was in secretory configuration (11.8 +/- 0.7% vs. 6.7 +/- 0.5%; 1-min suckled vs. nonsuckled control; mean +/- SE). Moreover, the fraction of the IL in secretory configuration continued to increase after 5 and 10 min of nursing (to 16.0 +/- 0.8% at 5 min and 18.2 +/- 0.7% at 10 min). In contrast, serum PRL was not significantly elevated above the control level a...
An Automatic Drug Discovery Workflow Generation Tool Using Semantic Web Technologies

Recent trends in life science and the pharmaceutical industry indicate that the drug discovery process could benefit greatly from both web service and semantic web technology. While web services provide a platform to allow different applications to interact with each other programmatically, semantic web developments are aiming at making web content machine-understandable and meta-level exploitation for data and computation possible. In this paper we demonstrate an automatic drug discovery workflow generation tool using semantic web service technologies. More specifically, we extend standard web services with semantic annotations specified in the domain ontology to enable semantic level interoperability. We also implement a service composition algorithm using linear planning approach, and using such an algorithm meaningful workflows for drug discovery could be generated automatically.
Multiplex, Fusionplex and Autoplex: three generations of information integration

We describe three generations of information integration systems developed at George Mason University. All three systems adopt a virtual database design: a global integration schema, a mapping between this schema and the schemas of the participating information sources, and automatic interpretation of global queries. The focus of Multiplex is rapid integration of very large, evolving, and heterogeneous collections of information sources. Fusionplex strengthens these capabilities with powerful tools for resolving data inconsistencies. Finally, Autoplex takes a more proactive approach to integration, by "recruiting" contributions to the global integration schema from available information sources. Using machine learning techniques it confronts a major cost of integration, that of mapping new sources into the global schema.
Slower heart rates for healthy hearts: time to redefine tachycardia?

The management of atrial fibrillation, even in the modern era, remains complex and challenging. Preventing atrial fibrillation occurrence by identifying and favorably improving modifiable risk factors thus assumes great importance. It is well known that hypertension and resultant structural heart disease contributes significantly to the incidence of atrial fibrillation.1,2 The Losartan Intervention For End point reduction in hypertension (LIFE) study thus far has shown us that angiotensin-receptor blockade and reduction in left ventricular hypertrophy, irrespective of blood pressure–lowering, reduces the incidence of new-onset atrial fibrillation.1,3 Article see p 337 In recent years, accumulating evidence has linked high resting sinus heart rates (HR) directly and indirectly to adverse cardiovascular outcomes.4,5 Epidemiological studies show resting HR to be an independent predictor of cardiovascular and all-cause mortality in general population as well as in hypertensive patients.6 The cardiovascular benefits offered by β-blockade in coronary artery disease and heart failure have, in part, been attributed to β-blocker–mediated HR reduction.7,8 Other studies have linked high baseline HR to the development of hypertension, to the progression of coronary artery disease, and to the triggering of myocardial infarction, ventricular dysfunction, and ventricular arrhythmias.6,9–11 In this issue of Circulation: Arrhythmia and Electrophysiology , Okin and colleagues12 examines the relationship of HR changes over time on risk of atrial fibrillation in hypertensive patients as part of the LIFE study. In this post hoc analysis of the prospective LIFE study, 8828 hypertensive patients with left ventricular hypertrophy by ECG but without a history of atrial fibrillation were followed for a mean of 4.7±1.1 years. New onset atrial fibrillation was determined by 12-lead ECG performed on an intermittent, infrequent basis (at baseline, 6 months, and yearly thereafter). Hypertension was treated with losartan or atenolol. Using a variety of analyses, higher in-treatment HR on serial …
Symmetric polynomials over Zm and simultaneous communication protocols

We study the problem of representing symmetric Boolean functions as symmetric polynomials over Z"m. We prove an equivalence between representations of Boolean functions by symmetric polynomials and simultaneous communication protocols. We show that computing a function f on 0-1 inputs with a polynomial of degree d modulo pq is equivalent to a two player simultaneous protocol for computing f where one player is given the first @?log"[email protected]? digits of the weight in base p and the other is given the first @?log"[email protected]? digits of the weight in base q. This equivalence allows us to show degree lower bounds by using techniques from communication complexity. For example, we show lower bounds of @W(n) on symmetric polynomials weakly representing classes of Mod"r and Threshold functions. Previously the best known lower bound for such representations of any function modulo pq was @W(n^1^2) [D.A. Barrington, R. Beigel, S. Rudich, Representing Boolean functions as polynomials modulo composite numbers, Comput. Complexity 4 (1994) 367-382]. The equivalence also allows us to use results from number theory to prove upper bounds for Threshold-k functions. We show that proving bounds on the degree of symmetric polynomials strongly representing the Threshold-k function is equivalent to counting the number of solutions to certain Diophantine equations. We use this to show an upper bound of O(nk)^1^2^+^@? for Threshold-k assuming the abc-conjecture. We show the same bound unconditionally for k constant. Prior to this, non-trivial upper bounds were known only for the OR function [D.A. Barrington, R. Beigel, S. Rudich, Representing Boolean functions as polynomials modulo composite numbers, Comput. Complexity 4 (1994) 367-382]. We show an almost tight lower bound of @W(nk)^1^2, improving the previously known bound of @W(max(k,n)) [S.-C. Tsai, Lower bounds on representing Boolean functions as polynomials in Z"m, SIAM J. Discrete Math. 9 (1996) 55-62].
Search for SM Higgs decaying to two W bosons at CMS

Updated results of searches for the standard model Higgs boson decaying to two W bosons in pp collisions at √s =8 TeV are reported. The fully leptonic (WW→ 2l 2ν ) and semileptonic (WW→ lνjj final state searches are presented. The event sample corresponds to an integrated luminosity of 12 fb−1 collected by the CMS detector in 2012. The 2011 results obtained at √s =7 TeV for an integrated luminosity of 5 fb−1 are added to the analysis. The leptonic channel observes an excess at M=125 GeV with a significance of 3.1σ . Upper limits are derived for the remainder of the mass range up to 600 GeV. Results are also presented for Higgs production in association with a W boson, leading to the 3l 3ν final state using 5 fb−1 collected at √s =8 TeV combined with data collected in 2011.
Finding defects in a 22 nm node wafer with visible light

Despite a diffraction limited lateral resolution of 360 nm, we detected 20 nm by 110 nm defects in a patterned 22 nm node wafer using quantitative phase and amplitude images from epiillumination diffraction phase microscopy.