cssi/SciSciGPT-SciSciNet huggingface dataset:
Posets whose monoids of order-preserving maps are regular

The purpose of this paper is to determine all posetsP such that the monoid of all order-preserving maps ofP intoP is regular in the semigroup-theoretic sense.
Statistical analysis of satellite-observed trade wind cloud clusters in the western North Pacific

Composite upper-air soundings have been constructed relative to 1 257 individual satellite-observed mesoscale (3–6° latitude) trade wind cloud clusters in the western tropical North Pacific. Clusters have been stratified into five categories: pre-storm clusters (166 cases treated), developing clusters (211), conservative clusters (537), non-conservative clusters (135), and dying clusters (208). A sixth category has been specified for clear areas (553). Rawinsonde observations from 14 island stations for the two-year period of October 1966 to October 1968 provide composited data for 16 pressure levels from the surface to 30 mb. Approximately 12 000 observations make up the data sample. Computerized composited summaries for each group of clusters have been made from Northern Hemisphere Data Tabulations (NHDT) tapes for wind, vorticity, divergence, kinetic energy, temperature, moisture, stability, and isobaric heights. Mass and thermal balances are very well satisfied by the composited data. Significant differences in the low-level horizontal wind shears exist among the six categories. The pre-storm and developing clusters exhibit large low-level cyclonic shears, whereas the remaining cloud categories show weaker cyclonic shears. The clear areas show a marked anticyclonic low-level wind shear. The relative vorticities are mostly determined by shears of the zonal wind. East-west shears of the meridional wind are of secondary importance. These cloud clusters may be viewed as typical of the usual easterly trade wave only if the latter is primarily interpreted as a shearing phenomena of the zonal trade wind. These observations generally support the contention of the importance of low-level frictionally forced convergence in the zonal shearing environment north of the equatorial trough as the mechanism for producing and maintaining these clusters (some of which later develop into typhoons). DOI: 10.1111/j.2153-3490.1973.tb00617.x
A simulation study of the convergence properties of the EM algorithm for image reconstruction in Positron Emission Tomography

We have studied certain characteristics of the Expectation — Maximization (EM) Algorithm for image reconstruction in Positron Emission Tomography (PET). The convergence and image quality have been studied using a series of simulation experiments. We. comment on the impact that different level of count rate has on the image quality, as it is expressed in terms of root mean square (RMS) error, and the region of feasible images. We observe the difference in the convergence rate of local regions in the field of view that have different activity levels in order to demonstrate the need of a new stopping criterion that will take into account the nonuniform recovery of the true activity resolution in the image plane.
Before the Civil Rights Revolution: The Old Court and Individual Rights

Individual Rights in a Federal System The Scope of Constitutionally Protected Rights The Dilemma of Race The Criminal Defendant The Old Court and Individual Rights Reappraised Bibliography Index
Clinical appraisal of intra-arterial priscoline therapy in the management of peripheral arterial diseases.

Priscoline can be given intra-arterially without difficulty. Untoward reactions are infrequent even in older patients. Intra-arterial administration was often effective in patients who did not respond to oral Priscoline. Although maximal vasodilatation may not be achieved by giving Priscoline intra-arterially, the degree of vasodilatation obtained is often adequate for a clinical effect. Results in 250 patients indicate that intra-arterial Priscoline is most useful in the treatment of ischemic rest pain resulting from organic vascular disease. Improvement in exercise tolerance was infrequent. Causalgia, delayed wound healing and ulceration in Reynaud's disease responded favorably in some instances.
Analysis of isotachic patterns in displacement chromatography

Abstract Most previous theoretical treatments of displacement chromatography have been confined to systems that follow the competitive Langmuir isotherm. With the assumption of such idealized multi-component adsorption behavior, in a sufficiently long column the final outcome of the process is always expected to be an isotachic displacement train having a series of adjacent separated bands of increasing concentration. Several recent reports, however, suggest that no such train forms when the single-component isotherms of the separands cross. In order to examine the possibility of separation under such conditions, the stability of the isotachic pattern is analyzed and criteria for displacement and for stability of the resulting boundaries are established. The approach requires the knowledge of the multi-component isotherm that governs the adsorption of the separands. As the competitive Langmuir isotherm completely fails to represent such behavior, the pertinent multi-component isotherms are generated from Langmuir single-component isotherms within the framework of the ideal adsorbed solution model. The results obtained with such a multi-component isotherm in binary separations show that three operating regions in displacement chromatography can be identified when the single-component isotherms of the separands cross. In one region at sufficiently low concentrations, the two components separate and appear in the same order as in linear chromatography. In a second region at sufficiently high concentrations, the bands are predicted to separate but appear in the reverse order. In the third region at intermediate concentrations, complete separation is not possible, and the resulting isotachic pattern contains a mixed zone. The stability analysis presented here facilitates the prediction of the outcome of displacement without the need for arduous computation; it is fairly general and may be applied to systems that follow other multi-component isotherms.
Incorporation of Wind Effects into Boussinesq Wave Models

Recent advances in the Boussinesq modeling of nearshore hydrodynamics offer a platform for the study of wind effects on wave transformation and breaking-generated nearshore circulation. The paper documents: (1) the new parameterization of the momentum flux transferred from the wind to surface gravity waves in the coastal region on the basis of the field observations; (2) the implementation of the parameterized wind stress into phase-resolving Boussinesq wave models; (3) the development of empirical breaking criteria with the wind effect based on the existing laboratory data; and (4) the tests of the extended Boussinesq model against field observations and empirical results with respect to wind drag coefficients over shoaling waves and wave growth on a shallow lake. Fairly good agreement between the model results and measurements is observed. The methodology for the parameterization of the wind stress as a function of wave steepness and wind speed as well as the extended Boussinesq model incorporating the wind forcing can be used as a tool to improve our understanding of wind effects on nearshore wave propagation and horizontal circulation.
Death from drowning: defining a new challenge for child survival in Bangladesh

The study focuses on children less than 5 years old and explores the epidemiological profile and correlates of drowning as a challenge to child survival in Bangladesh. Two data sources from Bangladesh, a cohort of 8,070 children followed for 2 years in a rural area and a nation-wide survey conducted in 1996-97 have been used. In addition, a systematic review of the literature has been conducted spanning the past two decades for analysis of drowning in children. Seventy drowning deaths were reported in the cohort and 726 deaths were reported in the national survey. Verbal autopsy and semi-structured interviews were conducted on all deaths. Drowning accounted for 43% of deaths in the cohort and 20% of deaths in 1-4-year-old children in the national survey. Most drowning deaths were in 12-23 month old children from falling into ditches and ponds. Communities provided valuable insights on possible interventions to reduce deaths due to drowning. Drowning is a newly recognized challenge for Bangladesh. Considerable research and programmatic work is required to understand the nature of the problem and develop appropriate interventions. This paper calls on aid agencies to create opportunities for drowning research and action in their work plans for the country.
Mixed-Conduction Model for Charge Transport in n -Type Cd Cr 2 Se 4

A model consisting of a conduction band and a subsidiary hole band is presented and applied to explain recently published transport data on Cd${\mathrm{Cr}}_{2}$${\mathrm{Se}}_{4}$ \char22{} a chalcogenide spinel semiconductor which becomes ferromagnetic below ${T}_{C}\ensuremath{\approx}130$\ifmmode^\circ\else\textdegree\fi{}K. The crucial feature of the data, which describe the behavior of $\ensuremath{\rho}$, ${R}_{0}$, and $Q$ from 300 to 4.2\ifmmode^\circ\else\textdegree\fi{}K, is the coincidence of maxima in $\ensuremath{\rho}$ and in $|{R}_{0}|$ with a minimum in $|Q|$, at 150\ifmmode^\circ\else\textdegree\fi{}K. The data cannot be explained in terms of a single conduction band, even if the spin splitting of the band and the effect of spin-disorder scattering are included, nor in terms of two-electron conduction bands. The present twoband model, wherein one band is the $n$-type conduction band and the other is a subsidiary hole band in the band gap, is the simplest one which can account for the data in a consistent manner. As $T$ is lowered from 300 to 150\ifmmode^\circ\else\textdegree\fi{}K, electrons freeze out onto the donors while the hole concentration increases; below 150\ifmmode^\circ\else\textdegree\fi{}K the hole concentration decreases while the electron concentration increases rapidly, because of the reduction of the donor ionization energy. These effects are due to temperature-dependent changes of the above interband energies associated with the assumed relative motions of the bands as the temperature is lowered below 186\ifmmode^\circ\else\textdegree\fi{}K - an effect due to intra-atomic exchange. Evidence for localized transport at very low temperatures is discussed briefly.
19.3 Reconfigurable SDR receiver with enhanced front-end frequency selectivity suitable for intra-band and inter-band carrier aggregation

The demand for increased wireless data throughput in future wireless communication and the lack of available wide contiguous frequency bands inspire the concept of aggregating multiple frequency bands in a Software-Defined Radio (SDR). A major challenge for such an SDR receiver is maintaining a high dynamic range in the presence of various desired and undesired signals spread over a wide frequency range. This paper introduces a receiver architecture that allows the RF front-end to be configured with various filtering profiles depending on signal scenarios while supporting intra-band multichannel carrier aggregation (contiguous and non-contiguous) with only one frequency synthesizer.
Microstructure and associated properties of YBCO superconductors prepared by melt-processing techniques

From the standpoint of applications, melt-processed bulk YBa2Cu3Ox (YBCO) superconductors are of considerable interest. In this paper, we studied the microstructure and levitation force of melt-processed YBCO, YBCO plus Y2BaCuO5, and YBCO+Pt. Large single-crystal samples, grown by a seeding technique, were also studied. The levitation force was highest in melt-processed samples made by the seeding technique.
Precipitation of Magnesium Aluminum Spinel from Alumina‐Matrix Solid Solution: I, Fundamental Concept and Precipitation Behavior

Al2O3 ceramics with magnesium aluminum spinel dispersion particulates were produced by a precipitation treatment of Al2O3-matrix solid solution, (Al1—2x,Tix,Mgx)2O3. We successfully constructed the precipitation process for synthesizing the nanocomposite, using the solubility dependence of titanium and magnesium in Al2O3 on the valence of titanium. Changing of the valence of titanium from 4+ to 3+ was accomplished by controlling the heating atmosphere, and, thereby, magnesium precipitation was promoted. The precipitation behavior was characterized using X-ray diffractometry, and the microstructure was observed using transmission electron microscopy. We confirmed that magnesium aluminum spinel nanosized particulate were precipitated in the Al2O3 grain.
TH ISOTOPE AND U-SERIES DISEQUILIBRIA IN SOME ALKALI BASALTS

The activities of 238U-series nuclides and 232Th have been measured by alpha spectrometry for nine alkali basalts from Heard island, Mt. Cameroon, Nyamuragira, and Nyiragongo. Large 226Ra enrichments are inferred to be absent from all, suggesting the absence of subsolidus fluids before magma genesis. Th isotope ratios are consistent with deep metasomatism forming carbonates beneath Nyiragongo, versus shallower metasomatism forming amphibole beneath Nyamuragira. In contrast, the Th/U ratio in the Nyamuragira source has increased with time, which is used to confirm that the Th/U ratio of the mantle is about 4.2.
Methiothepin reduces glucose utilization in forebrain regions of awake rats.

Local cerebral glucose utilization (LCGU) was measured, using the quantitative autoradiographic [14C]2-deoxy-d-glucose method, in 92 discrete brain regions of awake rats, at 1, 2, 3, or 4 h after administration of the serotonergic antagonist methiothepin 0.1 mg/kg IP. The drug produced a cataleptic behavior that peaked in intensity at 3 h after its administration. LCGU declined significantly in 35% of the 92 regions at one or more time points after methiothepin administration. No area of increased metabolism was found. The time-course of the decline in LCGU closely paralleled the intensity of catalepsy; the peak effect was at 3 h, when LCGU was significantly reduced in 32% of the regions examined (mean decline for all regions was 15%). Metabolic depression after methiothepin was most notable in the forebrain, where LCGU declined in many regions of the cerebral cortex, basal ganglia, and thalamus. Most of the regions affected by methiothepin possess a substantial number of serotonin receptors, although LCGU was also reduced in a few regions not primarily involved in serotonergic neurotransmission.
The phosphatase inhibitors, orthovanadate and levamisole, inhibit induction of erythroid differentiation and abrogate the associated inhibition of glycolysis

Alterations in protein tyrosine phosphate (PTP), lactate, and fructose 2,6-bisphosphate (F-2,6-P2) levels have been associated with induced MEL cell differentiation and commitment to terminal cell division (TCD). The possible relationships of perturbations in PTP metabolism and reduction in lactate formation during differentiation were investigated utilizing sodium orthovanadate, Na3VO4, primarily an inhibitor of PTP phosphatases, and levamisole, considered an alkaline phosphatase inhibitor. Both of these compounds were found to effectively inhibit the TCD-associated differentiation induced by DMSO, HMBA, and Na butyrate and to abrogate the differentiation-associated reduction in lactate accumulation due to these agents. However, they were found not to inhibit hemin-induced hemoglobin synthesis which is independent of TCD and does not alter lactate metabolism. Two brominated levamisole analogs, L-p-bromotetramisole and D-p-bromotetramisole, were also found to be inhibitors of TCD-associated differentiation and to be effective at even lower concentrations than levamisole. The changes in TCD-associated differentiation and lactate production exhibited the same concentration-dependence with respect to the inhibitors. These findings strengthened the theory that TCD-associated differentiation, decreased lactate production, and sensitivity to phosphatase inhibitors are all associated. Since the induction of MEL cell differentiation has been shown to be associated with, and is thought to be due to, the induction of PTP phosphatase activity and Na3VO4 is thought to inhibit the differentiation by inhibiting PTP phosphatase activity, the effect of levamisole on PTP levels was determined. Levamisole, like Na3VO4, was found to increase the tyrosine phosphate levels of proteins of similar molecular weights in intact cells in both the presence and absence of a differentiation inducer. Several phosphotyrosine-containing, similarly sized proteins were particularly affected by differentiation induction and by Na3VO4 and levamisole treatment. Changes in the levels of tyrosine phosphate-containing proteins of approximately 92-96, 60, and 38 kd were particularly noticeable. The induction of differentiation reduced PTP levels and inhibition of differentiation due to treatment with either Na3VO4 or levamisole increased their levels. These data suggest relationships between signal transduction pathways involved in differentiation and TCD, the regulation of lactate and F-2,6-P2 metabolism, and PTP levels.
Assembly of microtubules from preformed, ring-shaped protofilaments and 6-S tubulin

Tubulin obtained from disassembly of microtubules at 0°C exists in two forms: 6-S tubulin and a larger, curved or ring-shaped filament. These two forms have been separated chromat ographically and their roles in assembly examined. The purified rings reassemble to microtubules with high efficiency by uncoiling and straightening out, to be incorporated directly as protofilaments in the microtubule wall, and are thus identified as preformed protofilaments. Purified 6-S tubulin has not been observed to reassemble into microtubules by itself but will contribute to assembly when mixed with rings. Addition of glycerol at 0°C induces the 6-S tubulin to form rings, and the treated fraction will then reassemble to microtubules. Electron microscope observations indicate that assembly begins with the formation and growth of an incomplete microtubule wall. This wall grows wider by the addition of new protofilaments until the intact, circular microtubule, with 13 protofilaments, is formed. It is suggested here that growth of this wall from individual 6-S tubulin subunits may be energetically unfavorable. The direct incorporation of preformed protofilaments may be much more favorable, in which case the rings would be required for this initial stage of assembly.
Incorporation of Chemoselective Functionalities into Peptoids via Solid-Phase Submonomer Synthesis

A simple route to the introduction of a number of chemoselective functional groups into peptoids (oligo(N-substituted glycines)) by an extension of the standard solid-phase submonomer method is reported. The following groups were introduced: aminooxyacetamide, N-(carbamoylmethyl)acetohydrazide, mercaptoacetamide, 2-pyridinesulfenylmercaptoacetamide, and aldehyde-terminated peptoids. The method uses commercially available reagents, is fully compatible with standard peptoid submonomer synthesis conditions, is easily automated, and generates the desired functionalized peptoid in high yield and purity. Peptoids with suitable pairs of chemoselective ligation groups were joined in high yield.
Modeling spatial relation in skin lesion images by the graph walk kernel

Early skin cancer detection with the help of dermoscopic images is becoming more and more important. Previous methods generally ignored the spatial relation of the pixels or regions inside the lesion. We propose to employ a graph representation of the skin lesion to model the spatial relation. We then use the graph walk kernel, a similarity measure between two graphs, to build a classifier based on support vector machines for melanoma detection. In experiments, we compare the sensitivities and specificities of models with and without spatial information. Experimental results show that the model with spatial information performs the best in both sensitivity and specificity. Statistical test indicates that the improvement is significant.
The genetic relationships between ethanol preference, acute ethanol sensitivity, and ethanol tolerance in Drosophila melanogaster.

The relationship between alcohol consumption, sensitivity, and tolerance is an important question that has been addressed in humans and rodent models. Studies have shown that alcohol consumption and risk of abuse may correlate with (1) increased sensitivity to the stimulant effects of alcohol, (2) decreased sensitivity to the depressant effects of alcohol, and (3) increased alcohol tolerance. However, many conflicting results have been observed. To complement these studies, we utilized a different organism and approach to analyze the relationship between ethanol consumption and other ethanol responses. Using a set of 20 Drosophila melanogaster mutants that were isolated for altered ethanol sensitivity, we measured ethanol-induced hyperactivity, ethanol sedation, sedation tolerance, and ethanol consumption preference. Ethanol preference showed a strong positive correlation with ethanol tolerance, consistent with some rodent and human studies, but not with ethanol hyperactivity or sedation. No pairwise corr...
Predictors of rheumatoid arthritis patient‐physician communication about medication costs during visits to rheumatologists

Objective To examine the frequency with which medication costs are discussed, and the predictors of these discussions, during visits between rheumatologists and their patients with rheumatoid arthritis (RA). Methods Audiotapes of medical visits, patient questionnaires, medical records, and physician questionnaires were collected from March 2003 to December 2005. Data were collected from 200 RA patients from 4 rheumatology clinics. Audiotapes were coded for the presence of communication about medication costs using a detailed coding instrument. The final analysis sample included 193 patients and 8 rheumatologists. Stepwise multivariable logistic regression was used to examine the role of patient, physician, medication, and relationship characteristics on discussions of medication costs. Results Despite medication changes being made in more than 50% of the visits, only 34% of those visits included discussions of medication-related costs; 48% of these discussions were initiated by patients. In multivariable logistic regression models, communication about medication costs occurred more often when patients were white (compared with nonwhite) and reported an annual income of $20,000–$59,999 (compared with those earning ≥$60,000). Discussions about medication costs also were more common when physicians were white. Conclusion Although medication changes were common, medication costs were only discussed in one-third of the visits. Communication about medication costs was more common among patients who were white and in a middle income category. Disparities in communication about medication costs have the potential to negatively impact prescribing and subsequent medication use. Further research should examine potential disparities in communication about medication costs.
Sexual Size Dimorphism Predicts the Frequency of Sexual Cannibalism Within and Among Species of Spiders

Abstract: Sexual cannibalism varies widely among spiders, but no general evolutionary hypothesis has emerged to explain its distribution across taxa. Sexual size dimorphism (SSD) also varies widely among spiders and could affect the vulnerability of males to cannibalistic attacks by females. We tested for a relationship between SSD and sexual cannibalism within and among species of spiders, using a broad taxonomic data set. For most species, cannibalism was more likely when males were much smaller than females. In addition, using phylogenetically controlled and uncontrolled analyses, there was a strong positive relationship between average SSD of a species and the frequency of sexual cannibalism. This is the first evidence that the degree of size difference between males and females is related to the phylogenetic distribution of sexual cannibalism among a broad range of spiders.
Recombination of shower partons at high p T in heavy-ion collisions

A formalism for hadron production at high ${p}_{T}$ in heavy-ion collisions has been developed such that all partons hadronize by recombination. The fragmentation of a hard parton is accounted for by the recombination of shower partons that it creates. Such shower partons can also recombine with the thermal partons to form particles that dominate over all other possible modes of hadronization in the $3l{p}_{T}l8\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ range. The results for the high ${p}_{T}$ spectra of pion, kaon, and proton agree well with experiments. Energy loss of partons in the dense medium is taken into account on the average by an effective parameter by fitting data, and is found to be universal independent of the type of particles produced, as it should. Due to the recombination of thermal and shower partons, the structure of jets produced in nuclear collisions is different from that in $pp$ collisions. The consequence on same-side correlations is discussed.
The Piermont allochthon revisited and redefined at its type locality: Discussion

[Timms (2004)][1] has made a significant contribution to understanding a controversial structural feature of central New England: the Piermont allochthon (see [Hadley, 1942][2], [1950][3]; [Rumble, 1969][4]; [Moench, 1990][5], [1992][6], [1996][7], [1999][8]; [Billings, 1992][9]; [Rankin, 1996][10
Dialectical Inquiry in Strategic Planning: Extending the Boundaries

Two schools of thought, philosophical and empirical, are involved in a dialectical conflict over the application of dialectical inquiry (DI) to strategic planning. It is argued here that neither school can be accepted because the former violates the requirements of DI and the latter provides no framework for comparison with other planning methods. This paper emphasizes a need to focus future research on problem-solving technologies using free-simulation as an investigative tool.
Coronary embolism complicating aortic valve endocarditis: Treatment with placement of an intracoronary stent

A 37-year-old man, who had received 3 weeks of antimicrobial therapy for aortic valve endocarditis, presented with an acute anteroseptal wall myocardial infarction. Coronary angiography demonstrated occlusion of the mid left anterior descending artery, thought to have been caused by embolization of a sterile vegetation. Following failure of balloon dilation to achieve vessel patency, this was achieved by placement of an intracoronary stent.
Cross sensor 3D face recognition performance

This paper considers the effect of using different probe and gallery sensors on the performance of 3D face recognition. We report results of recognition experiments using face scans of 120 different persons, taken with two different commercial scanners, each at two different times. Our matching algorithm is a version of ICP, which is a popular approach to 3D face recognition. We find substantial differences in recognition rate between the sensors considered in part due to the different types of imaging artifacts produced. When matching data across sensors, the higher-quality data should be the enrollment data.
High resolution physical mapping of 45S (5.8S, 18S and 25S) rDNA gene loci in the tomato genome using a combination of karyotyping and FISH of pachytene chromosomes

Karyotyping in combination with fluorescence in situ hybridization (FISH) on tomato pachytene chromosomes allowed identification and mapping of a major 45S (5.8S, 18S and 25S) rDNA site on the satellite of 2S and four minor loci, each at a proximal knob on 2L, 6S, 9S and 11S. Thus, the 45S rDNA loci are all located in heterochromatic regions. The five 45S sites are all transcriptionally active as evidenced by a maximum of ten nucleoli in meiotic cells at telophase or interphase. The 45S rDNA loci, as well as the 5S rDNA locus on 1S, were highlighted by chromomycin A3, a GC-specific DNA ligand; this result is consistent with the high GC content of the rDNA genes. Satellite size varied dramatically between genotypes. Enzymatic maceration of tomato anthers followed by squashing in acetocarmine produced high quality chromosomal preparations and subsequent FISH images by reducing the strong autofluorescence inherent in the nucleolus and cytoplasm of tomato meiotic cells. Our protocol has potential in the construction of an integrated cytological, classical and molecular map of tomato.
Bis(monoacylglycero)phosphate forms stable small lamellar vesicle structures: insights into vesicular body formation in endosomes.

Bis(monoacylglycero)phosphate (BMP) is an unusually shaped lipid found in relatively high percentage in the late endosome. Here, we report the characterization of the morphology and molecular organization of dioleoyl-BMP (DOBMP) with dynamic light scattering, transmission electron microscopy, nuclear magnetic resonance (NMR) spectroscopy, and electron paramagnetic resonance spectroscopy. The morphology of hydrated DOBMP dispersions varies with pH and ionic strength, and DOBMP vesicles are significantly smaller in diameter than phosphatidylcholine dispersions. At neutral pH, DOBMP forms highly structured, clustered dispersions 500 nm in size. On the other hand, at acidic pH, spherically shaped vesicles are formed. NMR and spin-labeled electron paramagnetic resonance demonstrate that DOBMP forms a lamellar mesophase with acyl-chain packing similar to that of other unsaturated phospholipids. 31P NMR reveals an orientation of the phosphate group in DOBMP that differs significantly from that of other phospholipids. These macroscopic and microscopic structural characterizations suggest that the biosynthesis of BMP on the inner luminal membrane of maturing endosomes may possibly produce budded vesicles high in BMP content, which form small vesicular structures stabilized by the physical properties of the BMP lipid.
On the motion of bubbles in a periodic box

The motion of spherical bubbles in a box containing an incompressible and irrotational liquid with periodic boundary conditions is studied. Equations of motion are deduced using a variational principle. When the bubbles have approximately the same velocity their configuration is Lyapunov stable, provided they are arranged in such a way so as to minimize the effective conductivity of a composite material where the bubbles are treated as insulators. The minimizing configurations become asymptotically stable with the addition of gravity and liquid viscosity. This suggests that a randomly arranged configuration of bubbles, all with approximately the same velocity, cannot be stable. Explicit equations of motion for two bubbles are deduced using Rayleigh's method for solving Laplace's equation in a periodic domain. The results are extended for more than two bubbles by considering pairwise interactions. Numerical simulations with gravity and liquid viscosity ignored show the bubbles form clusters if initially they are randomly arranged with identical velocities. The clustering is inhibited, however, if the initial velocities are sufficiently different. The variance of the bubbles’ velocities is observed to act like a temperature; a lesser amount of clustering occurs with increasing temperature. Finally, in considering the effects of gravity and liquid viscosity, the long time behaviour is found to result in the formation of bubble clusters aggregated in a plane perpendicular to the direction of gravity.
Mechanisms of molecular recognition in the pikromycin polyketide synthase

Abstract Background: Modular polyketide synthases (PKSs) produce a wide range of medically significant compounds. In the case of the pikromycin PKS of Streptomyces venezuelae , four separate polypeptides (PikAI–PikAIV), comprising a total of one loading domain and six extension modules, generate the 14-membered ring macrolactone narbonolide. The polypeptide PikAIV contains a thioesterase (TE) domain and is responsible for catalyzing both the last elongation step with methylmalonyl CoA, and subsequent release of the final polyketide chain elongation intermediate from the PKS. Under certain growth conditions this polypeptide is synthesized from an alternative translational start site, giving rise to an N-terminal truncated form of PikAIV, containing only half of the ketosynthase (KS 6 ) domain. The truncated form of PikAIV is unable to catalyze the final elongation step, but is able to cleave a polyketide chain from the preceding module on PikAIII (ACP 5 ), giving rise to the 12-membered ring product 10-deoxymethynolide. Results: S. venezuelae mutants expressing hybrid PikAIV polypeptides containing acyl carrier protein (ACP) and malonyl CoA specific acyltransferase (AT) domains from the rapamycin PKS were unable to catalyze production of 12- or 14-membered ring macrolactone products. Plasmid-based expression of a hybrid PikAIV containing the native KS 6 and TE domains, however, restored production of both narbonolide and 10-deoxymethynolide in the S. venezuelae AX912 mutant that generates a TE-deleted form of PikAIV. Use of alternative KS domains or deletion of the KS 6 domain within the hybrid PikAIV resulted in loss of both products. Plasmid-based expression of a TE domain of PikAIV as a separate polypeptide in the AX912 mutant resulted in greater than 50% restoration of 10-deoxymethynolide, but not in mutants expressing a hybrid PikAIV bearing an unnatural AT domain. Mutants expressing hybrid PikAIV polypeptides containing the natural AT 6 domains and different ACP domains efficiently produced polyketide products, but with a significantly higher 10-deoxymethynolide/narbonolide ratio than observed with native PikAIV. Conclusions: Dimerization of KS 6 modules allows in vivo formation of a PKS heterodimer using PikAIV polypeptides containing different AT and ACP domains. In such heterodimers, the TE domain and the AT 6 domain responsible for formation of the narbonolide product are located on different polypeptide chains. The AT 6 domain of PikAIV plays an important role in facilitating TE-catalyzed chain termination (10-deoxymethynolide formation) at the proceeding module in PikAIII. The pikromycin PKS can tolerate the presence of multiple forms (active and inactive) of PikAIV, and decreased efficiency of elongation by PikAIV can result in increased levels of 10-deoxymethynolide. These results provide new insight into functional molecular interactions and interdomain recognition in modular PKSs.
Local cell interactions and the control of gastrulation in the sea urchin embryo

Abstract The sea urchin embryo is a good model system for studying the role of mechanical and cell-cell interactions during epithelial invagination, cell rearrangement and mesenchymal patterning in the gastrula. The mechanisms underlying the initial invagination of the archenteron have been surprisingly elusive; several possible mechanisms are discussed. In contrast to its initial invagination, the cellular basis for the elongation of the archenteron is better understood: both autonomous epithelial cell rearrangement and further rearrangement driven by secondary mesenchyme cells appear to be involved. Experiments indicate that patterning of freely migrating primary mesenchyme cells and secondary mesenchyme cells residing in the tip of the archenteron relies to a large extent on information resident in the ectoderm. Interactions between cells in the early embryo and later cell-cell interactions are both required for the establishment of ectodermal pattern information. Surprisingly, in the case of the oral ectoderm the fixation of pattern information does not occur until immediately prior to gastrulation.
Impact of bowel preparation on efficiency and cost of colonoscopy

OBJECTIVES: The impact of bowel preparation on the cost and efficiency of colonoscopy is uncertain. The aim of this study was to measure the impact of bowel preparation on total direct cost as well as procedure time and volume. METHODS: For 200 consecutive outpatient colonoscopies in persons with intact colons both at a private university hospital and at a public university hospital, we recorded the time spent suctioning fluid and feces from the colon and the time spent washing the colon to clean the mucosa. We prospectively asked colonoscopists to designate examinations that should be repeated at an interval sooner than would otherwise be recommended because of imperfect preparation. The data were used to perform a cost analysis of the economic effect of bowel preparation on direct costs of colonoscopy. RESULTS: Suctioning fluid and washing occupied 6% and 1.5% of total examination time (including insertion and withdrawal) at the public hospital and 9% and 1.3% at the private hospital. Patients at the public hospital were more likely to have an aborted examination (6.5% vs 1%, p = 0.004) and to be brought back earlier than suggested or required by current practice standards because of imperfect bowel preparation (20% vs 12.5%, p = 0.04). Cost analysis indicated that to complete the initial examinations and the first round of surveillance, imperfect bowel preparation resulted in a 12% increase in costs at the university hospital and a 22% increase at the public hospital. CONCLUSIONS: The increase in colonoscopy costs associated with imperfect preparation is substantial, and seems likely to vary among practices. Aborted examinations and surveillance examinations performed earlier than recommended because of imperfect preparation are appropriate targets for continuous quality improvement programs. More reliable bowel preparations, or measures to improve patient compliance with bowel preparation, could significantly reduce the costs of colonoscopy in clinical practice.
Following the Reactions of Mechanism-Based Inhibitors with β-Lactamase by Raman Crystallography†

The reactions between three clinically relevant inhibitors, tazobactam, sulbactam, and clavulanic acid, and SHV beta-lactamase (EC 3.5.2.6) have been followed in single crystals using a Raman microscope. The data are far superior to those obtained for the enzyme in aqueous solution and allow us to identify species on the reaction pathway and to measure the rates of the accumulation and decay of these species. A key intermediate on the reaction pathway is an acyl enzyme formed between Ser70 and the lactam ring's C=O group. By using the E166A deacylation deficient variant of the enzyme, we were able to focus on the process of acyl enzyme formation. The Raman data show that all three inhibitors form an enamine-type acyl enzyme reaching maximal populations at 10, 22, and 29 min for sulbactam, clavulanic acid, and tazobactam, respectively. The enamine intermediate exhibits a characteristic and relatively intense band near 1595 cm(-1) due to a stretching motion of the O=C-C=C-NH moiety that shifts to lower frequency upon NH ND exchange. This feature was used to follow the kinetics of enamine buildup and decay in the crystal. Quantum mechanical calculations support the assignment of the 1595 cm(-1) band, as well as several other bands, to a trans-enamine species. The Raman data also demonstrate that the lactam ring opens prior to enamine formation since the lactam ring carbonyl (C=O) peak disappears prior to the appearance of the enamine 1595 cm(-1) band. Tazobactam appears to form approximately twice as much enamine intermediate as sulbactam and clavulanic acid, which correlates with its superior performance in the clinic, a finding that may bear on future drug design.
Calculation of Rigid-Body Conformational Changes Using Restraint-Driven Cartesian Transformations

We present an approach for calculating conformational changes in membrane proteins using limited distance information. The method, named restraint-driven Cartesian transformations, involves 1) the use of relative distance changes; 2) the systematic sampling of rigid body movements in Cartesian space; 3) a penalty evaluation; and 4) model refinement using energy minimization. As a test case, we have analyzed the structural basis of activation gating in the Streptomyces lividans potassium channel (KcsA). A total of 10 pairs of distance restraints derived from site-directed spin labeling and electron paramagnetic resonance (SDSL-EPR) spectra were used to calculate the open conformation of the second transmembrane domains of KcsA (TM2). The SDSL-EPR based structure reveals a gating mechanism consistent with a scissoring-type motion of the TM2 segments that includes a pivot point near middle of the helix. The present approach considerably reduces the amount of time and effort required to establish the overall nature of conformational changes in membrane proteins. It is expected that this approach can be implemented into restrained molecular dynamics protocol to calculate the structure and conformational changes in a variety of membrane protein systems.
Progress toward a DoD Ground Vehicle Tradespace and Affordability Analysis Framework

Abstract During ground system conceptual design and engineering development many tradeoff decisions are made to balance functional performance, cost, risk, robustness, reliability, interoperability, growth margin, and other life-cycle characteristics. Tradespace analysis reveals and quantifies the compound and ripple effects and interactions among performance requirements and system design options. An analytic tradespace framework is an executable model that represents the logical and causal relationships among vehicle subsystems and system performance characteristics. Logical relationships define compatibility requirements between interacting subsystems. Causal relationships quantify higher level system attributes as functions of lower level subsystem attributes. Research at the US Army, TARDEC, has been developing a generic ground system performance specification framework, and a ground system standard product classification hierarchy. The current research seeks to integrate these two frameworks with a unifying framework of the logical and causal relationships. The tradespace framework identifies the relevant subsystem attributes and how they interact to govern product performance and life-cycle characteristics, and identifies the subsystem interfaces and compatibility characteristics that constrain and enable practical ground vehicles. The objective is a qualitative and quantitative framework integrating system architecture and technology options with functional and life cycle performance to support design and performance requirement decisions. The goal is to integrate the ground system architecture and performance specification frameworks for interactive tradespace analysis and exploration. The research is motivated by, and grounded in, an understanding of the performance and affordability tradespace decisions and supporting analysis in ground vehicle development programs.
Intracellular secretory pathway and ultrastructural localization of interstitial procollagenase in human gingival fibroblasts.

Abstract Fibroblast-type collagenase, a neutral secretory metalloproteinase capable of cleaving interstitial collagen types 1-III, is expressed by a number of different cell types including fibroblasts, macrophages, osteoblasts, and keratinoyctes. To elucidate the secretory pathway of this enzyme, we examined the ultrastructural localization of this metalloproteinase in cultured human gingival fibroblasts, particularly the routing of the enzyme from the Golgi cisternae to the cell surface utilizing rabbit polyclonal antibodies raised against human fibroblast (pro)collagenase. For this purpose, one percent glutaraldehyde followed by gentle permeabilization with saponin gave superior preservation of both cellular morphology and intracellular antigenicity. At the light microscopic level, the reacting antibodies visualized by immunofluorescence and immunoperoxidase staining were localized intracellularly in the perinuclear region reflecting the Golgi apparatus. Immunoelectronmicroscopy using the pre-embedding technique and peroxidase or immunogold staining revealed electron dense label in large vacuoles indicating extended cisternae of the Golgi field. Vesicles were noted leaving the plasma membrane in long extensions. Moreover, intact vesicles containing the antibody reaction product appeared outside the membrane. In addition, most extracellular vesicular structures appeared empty of label suggesting that the collagenase had been liberated into the extracellular space. The latter observation was supported by the fact that the label was found also on the extracellular surface of the cells indicating a (re) association of collagenase with the outer cell membrane. These data demonstrate that the pathway of interstitial collagenase in human gingival fibroblasts is similiar to that of other secretory proteins.
K+ Efflux Is the Common Trigger of NLRP3 Inflammasome Activation by Bacterial Toxins and Particulate Matter

The NLRP3 inflammasome is an important component of the innate immune system. However, its mechanism of activation remains largely unknown. We show that NLRP3 activators including bacterial pore-forming toxins, nigericin, ATP, and particulate matter caused mitochondrial perturbation or the opening of a large membrane pore, but this was not required for NLRP3 activation. Furthermore, reactive oxygen species generation or a change in cell volume was not necessary for NLRP3 activation. Instead, the only common activity induced by all NLRP3 agonists was the permeation of the cell membrane to K⁺ and Na⁺. Notably, reduction of the intracellular K⁺ concentration was sufficient to activate NLRP3, whereas an increase in intracellular Na⁺ modulated but was not strictly required for inflammasome activation. These results provide a unifying model for the activation of the NLRP3 inflammasome in which a drop in cytosolic K⁺ is the common step that is necessary and sufficient for caspase-1 activation.
Low dose desferrioxamine can improve erythropoiesis in iron-overload hemodialysis patients without side effects.

Objective: Multiple blood transfusions were often required to treat anemia in uremia patients before the era of recombinant human erythropoietin (r-HuEPO). Iron overload thus frequently occurred in chronic hemodialysis patients. Desferrioxamine (DFO) is an effective chelating agent, which can remove excessive iron and can enhance erythropoiesis. Large dose DFO treatment is a therapy associated with the development of severe complications. In this study, a low dose DFO regime was used to treat iron overloaded hemodialysis patients. The efficacy and side effects of this regiment were evaluated.Materials and Methods: Eight iron overloaded chronic hemodialysis patients were enrolled in this study. All patients received DFO 500 mg intravenously twice-a-week for eight months. Serum aluminum, transferrin saturation (TFS) and r-HuEPO requirement were recorded before and after DFO treatment. Serum ferritin and hematocrit (Hct) were measured before, during, and after the DFO withdrawal period. All patients were eva...
Dependence of electron transfer kinetics of the ferrocene/ferrocenium couple on the viscosity in ambient temperature chloroaluminate ionic liquids

Abstract The heterogeneous electron transfer kinetics of the ferrocenium/ferrocene couple have been measured throughout the basic range of composition of the ambient temperature chloroaluminate ionic liquid composed of 1-ethyl-3-methylimidazolium chloride (ImCl) and aluminum chloride. Normal and reverse pulse voltammetries with pulse times as short as 5 μs were employed. After subtraction of the background currents, the experimental voltammograms were directly compared with those calculated from the COOL algorithm using a model for reversible and quasi-reversible electron transfer reactions. The standard rate constants, uncorrected for double layer effects, were found to decrease from 0.45±0.35 cm s −1 at 0.95:1 to 0.027±0.004 cm s −1 at 0.45:1 mole ratio of aluminum chloride to ImCl. Possible factors contributing to the observed dependence are discussed. The most likely reason for the retardation of the electron transfer rate is the slow relaxation of the increasingly associated basic ionic liquid.