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Chromosomal rearrangements of the human KMT2A/MLLgene are associated with de novoas well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2Agene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2Agene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5’-KMT2A, two patients had a 5’-KMT2Adeletion, and one ETV6::RUNX1patient had an KMT2Ainsertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2Arecombinome in acute leukemia patients. Besides the scientific gain of information, genomic breakpoint sequences of these patients were used to monitor minimal residual disease (MRD). Thus, this work may be directly translated from the bench to the bedside of patients and meet the clinical needs to improve patient survival.

A prototype broadband geodetic very long baseline interferometry system has been implemented, and measurements of the baseline length over approximately two years, between December 2014 and January 2017, have been made in the process of exercising the system, developing operational procedures, and assessing geodetic precision for the new broadband observing concept. In addition to developing a broadband signal chain and installing the instrumentation on both a new 12‐m antenna at the Goddard Geophysical and Astrophysical Observatory and the 18‐m Westford antenna at the Massachusetts Institute of Technology Haystack Observatory, it was necessary to develop new correlation and analysis procedures to process the four‐band, dual‐linear‐polarization data. A geodetic analysis of the data from 19 sessions that were observed during this period yielded a weighted root‐mean‐square deviation of the baseline length residuals about the weighted mean of 1.6 mm. These results validate several of the expectations set forth for the vision of the next‐generation geodetic very long baseline interferometry system. We demonstrated the first broadband VLBI systems for high‐precision space geodesyWe developed procedures for data acquisition and analysis of the broadband geodetic dataWe generated the first VGOS baseline length time series

Children with P2RY8-CRLF2-positive acute lymphoblastic leukemia have an increased relapse risk. Their mutational and transcriptional landscape, as well as the respective patterns at relapse remain largely elusive. We, therefore, performed an integrated analysis of whole-exome and RNA sequencing in 41 major clone fusion-positive cases including 19 matched diagnosis/relapse pairs. We detected a variety of frequently subclonal and highly instable JAK/STAT but also RTK/Ras pathway-activating mutations in 76% of cases at diagnosis and virtually all relapses. Unlike P2RY8-CRLF2 that was lost in 32% of relapses, all other genomic alterations affecting lymphoid development (58%) and cell cycle (39%) remained stable. Only IKZF1 alterations predominated in relapsing cases (P=0.001) and increased from initially 36 to 58% in matched cases. IKZF1’s critical role is further corroborated by its specific transcriptional signature comprising stem cell features with signs of impaired lymphoid differentiation, enhanced focal adhesion, activated hypoxia pathway, deregulated cell cycle and increased drug resistance. Our findings support the notion that P2RY8-CRLF2 is dispensable for relapse development and instead highlight the prominent rank of IKZF1 for relapse development by mediating self-renewal and homing to the bone marrow niche. Consequently, reverting aberrant IKAROS signaling or its disparate programs emerges as an attractive potential treatment option in these leukemias.

In this work temperature inhomogeneities and their influence on PEMWE performance of industrial-scale stacks are investigated. Three temperature differences are examined: (i) between the inlet and outlet, (ii) in-between the cells of a stack, (iii) between the cell’s solid materials and the fluids. A validated stack model for temperature and performance is presented which is used to quantify the above-mentioned temperature fields and their influences on current density distribution and cell voltages. For a chosen scenario, with current densities of 2.0 A cm−2, fluid inlet temperatures of 60 °C and flow-rates of 0.15 kg s−1m−2, peak temperature differences amount to 8.2 K along-the-channel. This relates to inhomogeneities of current density of up to 10% inside a cell and deviations of cell voltage of 9 mV in-between cells in the center of the stack and outer cells. For higher current densities these differences increase further. More homogeneous temperatures allow operation at elevated average temperatures without exceeding temperature limitations and reduce the spread of degradation mechanisms. Hence, homogenous profiles lead to a more hole-some utilization of electrolysis stacks. Therefore, the ability to homogenize via alternative operation such as higher flow-rate, higher pressure and altered routing of fluid-flow is analyzed.

We have developped a mode-locked Ce, Nd:YAG laser end-pumped by a 500 mW laser diode. With a short cavity configuration the cw optical output power was 155 mW, which corresponds to an optical efficiency of 30.9 % and an electrical efficiency of 9.5 %. A cavity length extended to 1.4 m allows mode -locked operation at 106 MHz and pulses widthes of 150 ps have been obtained with an average power of 23 mW.

ABSTRACTUsing the BacT/Alert automated system, we conducted a 1-year retrospective study on blood cultures, focusing on the relevance of routine use of the anaerobic bottle. The rate of patients with positive blood cultures was 19.7%. Among these, 13.5% had a positive anaerobic bottle in the absence of any aerobic bottle, and 2/3 of these grew with nonobligate anaerobes. These patients were hospitalized in 20 out of 26 wards of the hospital group. For 65.4% of the monomicrobial-positive blood cultures growing Enterobacteriaceae, the anaerobic bottle detected growth earlier than the corresponding aerobic bottle. These data suggest that, in our institution, the use of an anaerobic bottle is still relevant.

Objectives: Over a 3 year period (2000–2003) 21 Escherichia coli, 5 Klebsiella pneumoniae, 1 Serratia marcescens and 1 Proteus mirabilis producing CTX-M-type β-lactamase were collected from five different hospitals in Paris, France. This study was conducted to analyse the genetic environment of these 28 blaCTX-M genes.Methods: Antimicrobial susceptibility testing was performed by the disc diffusion method and MICs of various β-lactams were determined by an agar dilution method. PCR was used to detect and sequence alleles encoding CTX-M, TEM, SHV and CMY enzymes. The genetic environment was analysed by amplification and direct sequencing using various set of PCR primers or cloning in pBK-CMV.Results: Sequence analysis revealed that these isolates contained seven different blaCTX-M genes: blaCTX-M-1 (4 strains), blaCTX-M-2 (2 strains), blaCTX-M-3 (4 strains), blaCTX-M-9 (1 strain), blaCTX-M-14 (5 strains), blaCTX-M-15 (11 strains), blaCTX-M-24 (1 strain). TEM-1 was associated with CTX-M-type enzymes in 15 isolates. Two strains produced both CTX-M-15 and SHV-2 or CTX-M-14 and CMY-2. In 25 strains the insertion sequence ISEcp1 was located upstream of the 5′ end of the blaCTX-M gene. Among these strains, in five isolates, ISEcp1 was disrupted by insertion sequences such as IS26 (in three of them) or IS1 or IS10. Insertion sequence IS903 was found downstream of blaCTX-M-14 or blaCTX-M-24. Examination of the other three blaCTX-M genes (two blaCTX-M-2 and one blaCTX-M-9) by cloning, sequencing and PCR analysis revealed the presence of complex Class 1 integrons, In35, an integron similar to In60 and a novel integron.Conclusions: This work further confirmed the predominant role of ISEcp1 in the mobilization of blaCTX-M genes of the CTX-M-1 cluster and the presence of In35, of an integron similar to In60 and a novel complex Class 1 integron.

Gas-expanded liquids offer many advantages as superior solvents for asymmetric hydrogenation reactions. To implement such applications, knowledge of the phase behavior of hydrogen with these tunable solvents is imperative. Phase boundary data are reported for the ternary system of carbon dioxide, methanol, and hydrogen at 313.2 K and pressures up to 21.7 MPa. The data were measured in a variable-volume windowed vessel by visual observation of one- to two-phase transitions.

New pure component parameters are presented for the MOSCED limiting activity coefficient model for 133 solvents with an absolute average deviation of 10.6% to experimental literature data. The MOSCED model has been applied to solid−liquid equilibria correlation and compared with the experimental data available in the literature. The correlation of solubility of 26 solids in organic solvents has an average absolute deviation of 25%. This compares favorably to the prediction of the modified UNIFAC model.

ZUSAMMENFASSUNGAktuelle Entwicklungen in der IuK-Technik verändern unser alltägliches Arbeits- und Privatleben. Diese Entwicklungen schlagen sich insbesondere in der großen Vielfalt der Endgeräte sowie deren zunehmender Mobilität und dynamischer Vernetzung nieder. Geräte mit sehr unterschiedlichen Ressourcenausstattungen und Fähigkeiten (Mobiltelefone, PDAs, Laptops, Appliances, Mainframes, Edutainment-Geräte, elektronisch gesteuerte Herzschrittmacher etc.) sind bereits heute im Einsatz. Im Bereich der Kommunikationsnetze ist die Entwicklung geprägt durch den Schritt hin zu ubiquitären Netzen. Dieser Technologiewandel erschließt uns neue Anwendungen und auch neue Anwendungsbereiche, stellt aber gleichzeitig die Forschung im Bereich der IT-Sicherheit vor neue Herausforderungen. Die im Titel des Beitrags gestellte Forderung nach ubiquitärer und damit nach allgegenwärtiger, durchgehender Sicherheit für dynamische, mobile Systeme fasst diese Herausforderungen zusammen. Der Beitrag zeigt auf, dass ein Paradigmenwechsel im Bereich IT-Sicherheit notwendig ist, um die Vision der allgegenwärtigen Sicherheit als selbstverständlichem Qualitätsmerkmal zukünftiger Systeme zu verwirklichen.

Vapor−liquid equilibria, molar volumes, and volume expansion for several binary mixtures of organic solvents with carbon dioxide have been determined using a visual synthetic technique at temperatures from (298 to 333) K. The binary vapor−liquid equilibrium and saturated liquid molar volume of CO2 + acetone, + acetonitrile, + dichloromethane, + nitromethane, + N-methyl-2-pyrrolidone, + perfluorohexane, + 2-propanol, + tetrahydrofuran, + toluene, and + 2,2,2-trifluoroethanol were measured at temperatures from (298.2 to 333.2) K. The VLE correlated well using the Patel−Teja equation of state with Mathias−Klotz−Prausnitz mixing rules. The solubility of CO2 in the various solvents is explained by considering the intermolecular interactions of CO2 in solution.

Gas-expanded liquids are tunable media for reaction and separation. We report that gas-expanded liquids under CO2 pressure are unique media for amine formation and separation. In the heterogeneous hydrogenation of benzonitrile and phenylacetonitrile with NiCl2/NaBH4 in CO2-expanded ethanol, the primary amines are protected by CO2 so that the yield of the primary amines is greatly increased and the production of the secondary amines is effectively suppressed. In the homogeneous hydrogenation of benzonitrile and phenylacetonitrile with RhH(P-i-Pr3)3 and benzophenone imine with Rh(1,5-C8H12){P(C6H5)3}2]PF6 in CO2-expanded tetrahydrofuran, the primary amines are separated in situ in the form of solid carbamic acids and/or ammonium carbamates with increased yield while the catalyst remains in the solution. These results demonstrate the potential for using modest pressures of CO2 to facilitate reactions as well as to separate products.

Fluorous biphasic chemistry enables the recovery of homogeneous catalysts but presents engineering challenges because of issues concerning phase contacting and solvent loss. The addition of gaseous CO2 to fluorous−organic biphasic systems results in a single homogeneous liquid phase at temperatures well below the upper critical solution temperature of the binary liquid mixture. This phenomenon is due to the high solubility of CO2 in both organic liquids and fluorocarbons, and it facilitates reactions and can also reduce fluorous solvent losses. We demonstrate two homogeneously catalyzed reactions, a hydrogenation and an epoxidation, which result in an enhancement in the turnover frequency of 70% and 50%, respectively, for the CO2-merged phase relative to the fluorous biphasic system. This creates new opportunities for the use of fluorous-sequestered catalysts.

Gas-expanded liquids are tunable media for reactions and separations. We report for the first time that CO2-expanded alcohols are catalytic media for cyclohexanone acetal formation. This process offers the opportunity to replace some environmentally harmful acid catalysts, as the CO2-based acid catalysts are self-neutralizing and result in no solid waste. We propose that the alkylcarbonic acids formed in situ from CO2 and alcohols are the acid catalysts and that the catalytic capacity can be tuned with CO2 pressure and temperature. The kinetics of cyclohexanone acetal formation in CO2-expanded methanol was investigated under various CO2 pressures over a temperature range of 25−50 °C without the addition of acid. Pseudo-first- and second-order rate constants were evaluated. These rate constants go through a maximum and the superficial activation energies go through a minimum between 10 and 40 bar of CO2.

High-pressure phase behavior has been measured for CO2/methanol/tetramethylammonium bicarbonate (TMAB) and CO2/methanol/TMAB/water systems at (25 and 70) °C and pressures up to 30 MPa. An increase in methanol concentration results in a decrease in the phase-transition pressure due to the higher miscibility of methanol and salt in CO2. At higher methanol concentrations, single phase mixtures could be achieved at moderate pressures with up to 70 mol % CO2. As expected, the addition of water sharply increases the phase transition pressure. The experimental results for the above systems were modeled using the Peng−Robinson equation of state; model predictions were found to be sensitive to adjustable parameters.

We analyzed 19 clinical isolates of the family Enterobacteriaceae (16 Escherichia coli isolates and 3 Klebsiella pneumoniae isolates) collected from four different hospitals in Paris, France, from 2000 to 2002. These strains had a particular extended-spectrum cephalosporin resistance profile characterized by a higher level of resistance to cefotaxime and aztreonam than to ceftazidime. The bla(CTX-M) genes encoding these beta-lactamases were involved in this resistance, with a predominance of bla(CTX-M-15). Ten of the 19 isolates produced both TEM-1- and CTX-M-type enzymes. One strain (E. coli TN13) expressed CMY-2, TEM-1, and CTX-M-14. bla(CTX-M) genes were found on large plasmids. In 15 cases the same insertion sequence, ISEcp1, was located upstream of the 5' end of the bla(CTX-M) gene. In one case we identified an insertion sequence designated IS26. Examination of the other three bla(CTX-M) genes by cloning, sequencing, and PCR analysis revealed the presence of a complex sul1-type integron that includes open reading frame ORF513, which carries the bla gene and the surrounding DNA. Five isolates had the same plasmid DNA fingerprint, suggesting clonal dissemination of CTX-M-15-producing strains in the Paris area.

ABSTRACTWe analyzed 19 clinical isolates of the family Enterobacteriaceae(16 Escherichia coliisolates and 3 Klebsiella pneumoniaeisolates) collected from four different hospitals in Paris, France, from 2000 to 2002. These strains had a particular extended-spectrum cephalosporin resistance profile characterized by a higher level of resistance to cefotaxime and aztreonam than to ceftazidime. The blaCTX-Mgenes encoding these β-lactamases were involved in this resistance, with a predominance of blaCTX-M-15. Ten of the 19 isolates produced both TEM-1- and CTX-M-type enzymes. One strain (E. coliTN13) expressed CMY-2, TEM-1, and CTX-M-14. blaCTX-Mgenes were found on large plasmids. In 15 cases the same insertion sequence, ISEcp1, was located upstream of the 5′ end of the blaCTX-Mgene. In one case we identified an insertion sequence designated IS26. Examination of the other three blaCTX-Mgenes by cloning, sequencing, and PCR analysis revealed the presence of a complex sul1-type integron that includes open reading frame ORF513, which carries the blagene and the surrounding DNA. Five isolates had the same plasmid DNA fingerprint, suggesting clonal dissemination of CTX-M-15-producing strains in the Paris area.

A novel class of tunable solvents facilitates recycle of homogeneous catalysts for both economic and environmental advantages. In a mixed organic−aqueous tunable solvent (OATS), reactions between water-soluble catalysts and moderately hydrophobic substrates can be run homogeneously, with subsequent phase separation for product purification and catalyst reuse. One example demonstrated is the dimethyl ether (DME)−water system, which has been employed as a benign alternative to organic solvents for alcohol dehydrogenase (ADH)-catalyzed reduction of hydrophobic ketones coupled with regeneration of the cofactor NADH. We also show the feasibility of a biphasic DME−water separation scheme to couple with the biocatalytic reaction. The subsequent downstream processing offers the advantages of easily isolating water-insoluble products from the aqueous phase and recycling enzyme−cofactor. Other OATS systems are discussed where the preferential dissolution of modest pressures of CO2 causes phase separations, which result in very large distribution coefficients of target molecules in the biphasic organic−aqueous system, with substantial promise as tunable solvents for biocatalysis.

Near-critical water (liquid water between 200 and 374 °C) offers an environmentally benign alternative for the replacement of undesirable solvents and catalysts. This work characterizes the solvent strength of liquid water at saturation pressure from ambient temperature to 275 °C in terms of its Kamlet−Taft dipolarity/polarizability, hydrogen-bond-donating acidity, and hydrogen-bond-accepting basicity using in situ UV−vis spectroscopy. The results suggest that near-critical water exhibits a wide range of polarity and hydrogen-bond-donor ability for tailoring chemical reactions and separations. These Kamlet−Taft solvent parameters can be used to correlate kinetic properties for reactions in water. As model reactions, the temperature-dependent kinetics of the hydrolyses of two nitroaromatic compounds, 4-nitroaniline and N,N-dimethyl nitroaniline, were determined in NCW in the temperature range of 200−275 °C. The hydronium ion dissociated from water promotes the initial hydrolysis reaction without the addition of any acid. Solvent effects on the rate constant were correlated with Kamlet−Taft solvent parameters based on a linear solvation energy relationship (LSER).

The first example of a phase-transfer-catalyzed alkylation reaction under supercritical fluid conditions is reported. The reaction is that of phenylacetonitrile and ethyl bromide in the presence of tetrabutylammonium bromide and potassium carbonate in supercritical ethane at 45, 60, and 75 °C and 138 bar. Results show that the reaction will go to completion in less than 24 h in the presence of the catalyst but that only a few percent conversion is achieved without it during the same period of time. The effects of catalyst concentration, temperature, and cosolvents are investigated. Catalyst solubility estimates and kinetic analyses suggest that the reaction takes place on the surface of the potassium carbonate particles. When the same reaction is attempted in supercritical carbon dioxide, both carboxylation and alkylation are observed. Cycloalkylation reactions between phenylacetonitrile and dibromoalkanes are also discussed.

An alternative means of epoxidation is reported that uses environmentally benign supercritical carbon dioxide as both a solvent and reactant in combination with aqueous H2O2, which is made possible through the in situ formation of peroxycarbonic acid. Experiments were conducted at 40 °C and 120 bar in which cyclohexene was epoxidized to 1,2-cyclohexene oxide and 1,2-cyclohexanediol in this aqueous−organic biphasic system. Through the addition of NaHCO3 and the hydrophilic cosolvent dimethylformamide, the conversion increased from 0.4 mol % (without additives) to 12.6 mol % (with 0.1 mol % NaHCO3 and 13 mol % dimethylformamide). The results suggest that the reaction occurs within the aqueous phase, which led to investigations using the water-soluble olefin 3-cyclohexen-1-carboxylate sodium salt as a means of verifying the reaction location. Epoxidation of 3-cyclohexen-1-carboxylate sodium salt went to completion in less than 20 h at 40 °C and 120 bar with an epoxide yield of 89 mol % and diol yield of 11 mol %.

Environmentally benign near-critical water offers substantial advantages over traditional organic solvents. In this work we use the hydrolyses of several substituted benzoate esters and a series of substituted anisoles as probes to elucidate the activity of the two ionic species in near-critical water. Each of these hydrolyses can run via both acid- and base-catalyzed pathways, as well as an SN2 pathway. An analysis of Hammett plots suggests that the benzoate esters hydrolyze autocatalytically, following an acid-catalyzed mechanism, whereas the anisoles are hydrolyzed via the SN2 mechanistic pathway. This work suggests that near-critical water offers significant potential, both as a benign solvent and as a reaction medium that does not require neutralization with acid or base after the desired reaction is complete.

The key to sustainable technology is achieving an economic benefit for environmental improvements. The tunability of benign compounds such as CO2 and water as supercritical and near-critical fluids offers improved performance and greater flexibility for separation and reaction processes, leading to economic advantages. Examples of such behavior are supercritical CO2 extractions and separations, CO2-expanded polar liquids for separations, and reactions in near-critical water. In each case the tunability is achieved through density changes or cosolvents and may augment product yield, quality, or rates.

Liquid−liquid equilibria are reported for binary mixtures of water with acetophenone, 1-octanol, anisole, and toluene in the temperature range of 370 K to 550 K. The data were measured in a variable-volume windowed vessel by a traditional cloud point technique. These results are in good agreement with data reported in the literature. Above 450 K binary data for the water + anisole and water + acetophenone systems have not been reported previously.

Currently, a shift of paradigm from sequential to distributed computing can be observed. Tremendous efforts are needed to cope with the challenging demands that are inherent to this transition. The two most important issues concern programming support for developing large-scale distributed applications and the efficient execution of such applications on top of a distributed hardware configuration. This paper presents a new language and object-based approach called MoDiS to cope with these demands. Distributed systems are developed and transformed into executables following a systematic, top-down driven method. Language-level is intended to mean that a high-level programming language is used to develop operating system services as well as user-level applications. The language-level concepts employed are based on objects and support advanced structuring features. Structural dependencies between objects are implicitly determined at the application level and exploited by the distributed resource management system to transform applications into efficient executables.

The hetero-Diels−Alder reaction between anthracene and excess 4-phenyl-1,2,4-triazoline-3,5-dione has been investigated in supercritical CO2 at 40 °C and pressures between 75 and 216 bar. Bimolecular reaction rate constants have been measured via fluorescence spectroscopy by following the decrease in anthracene concentration with reaction time. The reaction rate is elevated in the vicinity of the critical pressure. This difference is consistent with local composition enhancement and can be modeled with the Peng−Robinson equation of state.

Five nonelectrolyte solution models are used to predict infinite dilution activity coefficients (γ^∞) of five linear, four branched, and two cyclic alkanes in 67 solvents at 25 °C, and the results are compared with experimental data. The models use two distinct approaches to the prediction of γ^∞. The solution of groups concept provides the basis for three versions of the UNIFAC model:  original UNIFAC, γ^∞-based UNIFAC, and modified UNIFAC (Dortmund). The MOSCED and the SPACE models avoid the group concept and use only pure component parameters. For a database of 737 limiting activity coefficients, the SPACE model gave an average absolute error of 8.1%, and in only 13.3% of the cases were the errors worse than 15%. The modified UNIFAC model gave an absolute average error of 9.8%, and 32% of the predicted γ^∞ had errors larger than 15%. The SPACE approach also produced the most reliable estimations over a wide range of activity coefficient values.

We report the selective removal of a desired reaction intermediate with a supercritical fluid in a new synthesis route to poly(ethylene terephthalate), avoiding ethylene glycol. We have successfully catalyzed the esterification of terephthalic acid with ethylene oxide in a supercritical fluid with a series of quaternary ammonium salts to form mono(2-hydroxyethyl terephthalate). This desired monoester was removed from the involatile bed of terephthalic acid and catalyst by continuous extraction with supercritical fluid before subsequent reaction to the diester could take place.

Cosolvents exhibit significant effects on the partitioning behavior of dilute solutes between a supercritical CO2 fluid phase and cross-linked siloxane-based polymers. A spectroscopic technique was developed and applied that allows us to measure the partition coefficients of both the cosolvents and solutes between the two phases. The Sanchez−Lacombe lattice fluid equation of state was extended to represent a two-phase, four-component system and was quantitatively successful in representing the volumetric and phase-equilibria properties of such systems. We then apply the model and our data to investigate the magnitudes of stationary-phase effects in supercritical fluid chromatography and explore opportunities to use the model for a priori prediction of separation.

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This study experimentally examines the relationship between colony state and the behaviour of individual pollen and nectar foragers in the honey bee, Apis mellifera L. In the first experiment we test the prediction that individual pollen foragers from colonies with higher brood quantities should exhibit a greater work effort for pollen resources than individual pollen foragers from colonies with low brood quantities. Eight colonies were assigned into two treatment groups; HIGH brood colonies were manipulated to contain 9600±480 cm2 brood area; LOW brood colonies were manipulated to contain 1600±80 cm2 brood area. We measured colony brood levels over the course of the experiment and collected individual pollen loads from returning pollen foragers. We found that, while colonies remained significantly different in brood levels, individual pollen foragers from HIGH brood colonies collected larger loads than individuals from LOW brood colonies. In the second experiment we investigated the influence of colony size on the behaviour of individual nectar foragers. We assigned eight colonies to two treatment groups; LARGE colonies were manipulated to contain 35000±1700 adult workers with 3500±175 cm2 brood area, and SMALL colonies were manipulated to contain 10000±500 adult workers with 1000±50 cm2 brood area. We observed foraging trips of individually marked workers and found that individuals from LARGE colonies made longer foraging trips than those from SMALL colonies (LARGE: 1666.7±126.4 seconds, SMALL: 1210.8±157.6 seconds), and collected larter nectar loads (LARGE: 19.2±1.0 µl, SMALL: 14.6±0.8 µl). These results indicate that individual nectar foragers from LARGE colonies tend to work harder than individuals from SMALL colonies. Both experiments indicate that the values of nectar and pollen resources to a colony change depend on colony state, and that individual foragers modify their behaviour accordingly.

Supercritical fluid chromatography is a powerful technique for analysis, and it also provides a useful tool for the measurement of thermodynamic properties. For any application, the method involves equilibration between the mobile supercritical fluid phase and the polymeric stationary phase. The mobile-phase properties are often modified substantially with the addition of polar or protic cosolvents, but these adducts also cause changes in the stationary phases. In situ FTIR spectroscopy and the swelling of poly(dimethylsiloxane) (PDMS) are combined to quantify these changes due to partitioning of the cosolvent into and the swelling of the polymeric stationary phase as a function of fluid pressure. These results are used to evaluate the magnitude of the corrections for the changes in retention time of analytes, which affects both analytical methods and thermophysical property measurement.

Epstein-Barr virus (EBV) transforms resting B cells in vitro very efficiently. The nuclear viral protein EBV nuclear antigen 2 (EBNA2) is absolutely required for this process and also acts as a transcriptional activator of cellular and viral genes. As shown previously, EBNA2 transactivates the promoters of the viral latent membrane proteins. It interacts indirectly with an EBNA2-responsive cis element of the terminal protein 1 (TP1) promoter. To identify the sequences mediating EBNA2 transactivation of the bidirectional promoter region driving expression of the latent membrane proteins LMP and TP2 in opposite directions, we assayed the effects of EBNA2 on the activities of promoter deletion and site-directed mutants of TP2 and LMP promoter luciferase reporter gene constructs by cotransfections into EBNA2-negative Burkitt's lymphoma cells. We were able to delineate an 80-bp EBNA2-responsive region (EBNA2RE) between -232 and -152 relative to the LMP RNA start site which could also mediate EBNA2-dependent activation on a heterologous promoter. Sequences of 20 and 32 bp located at the 5' and 3' ends, respectively, of the EBNA2RE were both essential for EBNA2 responsiveness. Full transactivation of the LMP and TP2 promoters seemed to require 20 bp of 5' adjacent sequences in addition to the 80-bp element. Electrophoretic mobility shift assays revealed specific protein-DNA complexes formed at the EBNA2RE. Oligonucleotides from -181 to -152 and -166 to -132 relative to the LMP RNA start site visualized one B-cell and one B-cell-plus-HL60-specific retarded protein-DNA complex, respectively. Additionally, an oligonucleotide from -253 to -210 revealed two specific protein-DNA complexes with nuclear extracts from different B and non-B cells, suggesting also the binding of ubiquitously expressed proteins on the EBNA2RE. Thus, these experiments defined a 80-bp cis element sufficient for conferring EBNA2 inducibility and demonstrated specific interactions of cellular proteins at DNA sequences within the EBNA2RE, which are critical for transactivation by EBNA2.

A chromatographic technique was used to measure experimental capacity factors for the n-alkanes from C9H20 to C36H74 in CO2 from 308.2 to 348.2 K and from 100 to 240 bar. Infinite dilution activity coefficients, γi^∞, were calculated for the solid n-alkanes (C24H50 to C36H74) utilizing regular solution theory to characterize the stationary phase. This allowed the estimation of solubilities from capacity factors for the solid n-alkanes in CO2.

The rational design of separations in multicomponent systems depends on the quality of vapor−liquid equilibrium (VLE) data and the precision to which these data can be represented. In recent years, new experimental techniques have begun to yield better quality VLE data. Often these data warrant the use of more than two parameters per binary pair, which is common in the empirical Gibbs energy of mixing expressions used to represent such data. In this work, we propose two new expressions for representing the Gibbs free energy of mixing:  the four parameter Scott−Wilson and the five parameter Scott−Regular Solution−Wilson. A method for evaluating such expressions is presented, including our proposed technique of predicting γ^∞ in a mixed solvent from binary data only. For this, we measured γ^∞ in a mixed solvent system using differential ebulliometry.

A single Sanchez−Lacombe lattice fluid equation of state is used to model both phases for a polymer−supercritical fluid−cosolvent system. This method represents well over a wide pressure range both volumetric and phase equilibrium properties for a cross-linked poly(dimethyl siloxane) phase in contact with CO2 modified by a number of cosolvents. A single adjustable binary interaction parameter, obtained from swelling data of the polymer, is used to correlate both polymer dilation and solvent sorption.

This work reports the first studies designed to examine the detailed mechanism of a phase-transfer catalyzed reaction between a supercritical CO2 phase and a solid salt phase. The nucleophilic displacement of benzyl chloride with potassium cyanide to form phenylacetonitrile and potassium chloride was carried out with a tetraheptylammonium salt as the phase-transfer catalyst. The effects of various reaction variables on the kinetics were investigated, including the amount of catalyst, the amount of potassium cyanide, the presence of acetone cosolvent, and temperature. The kinetic data, along with catalyst solubility measurements, indicate that the operating reaction mechanism is a three-phase system consisting of a supercritical CO2 phase, a catalyst-rich phase, and a solid salt phase and that the reaction actually occurs in the catalyst-rich phase. Further, the reaction mechanism was investigated with two additional phase-transfer catalysts, 18-crown-6 and poly(ethylene glycol), and these results are consistent with the postulated three-phase mechanism.

The n → π* shift of benzophenone has been used to quantify solute−cosolvent interactions in supercritical ethane. Dilute solutions of benzophenone in cosolvent/supercritical ethane mixtures were studied at 35 °C from 50 to 100 bar over a range of cosolvent concentrations. The following cosolvents were chosen for investigation on the basis of their varying abilities to interact with benzophenone:  2,2,2-trifluoroethanol, ethanol, chloroform, propionitrile, 1,2-dibromoethane, and 1,1,1-trichloroethane. In the supercritical systems investigated here, hydrogen bonding of protic cosolvents to the carbonyl oxygen of benzophenone is the primary mechanism of the n → π* shift. The results of this investigation are consistent with a chemical−physical interpretation of cosolvent effects in supercritical fluids in the presence of strong specific solute−cosolvent interactions. The experimental results for the ethane/TFE/benzophenone system were analyzed by using integral equations in order to study the assumptions of the chemical−physical model. This combination of spectroscopic data with radial distribution function models provides a powerful tool for understanding cosolvent effects.

This paper presents a new predictive method for the sublimation pressures of heavy n-alkanes from C20H42 to C35H72 in the temperature range 308−348 K. The peculiar behavior of solid n-alkanes in terms of their heats of solid transitions is reviewed briefly. Also, the behavior of heat capacities of the n-alkanes through the solid−solid transitions is discussed, and the relative importance of this behavior is evaluated. Finally, the new expression for the sublimation pressures of n-alkanes is compared with other available correlations.

The first example of a phase-transfer-catalyzed reaction carried out in a supercritical fluid (SCF) is reported. The kinetics of the nucleophilic displacement of benzyl chloride with a bromide ion in SCF solvent CO2 in the presence of acetone cosolvent is presented. In addition, the solubility of tetraheptylammonium bromide (THAB) in SCF CO2 in the presence of acetone cosolvent is reported. The reaction rate was measured at 50 and 75 °C at pressures to 200 bar; the reaction was found to follow first-order, reversible kinetics for the reactions catalyzed by THAB and zero-order kinetics for reactions catalyzed by 18-crown-6.

The dominant variability modes in the Tropics are investigated and contrasted with the anomalous situation observed during the last few years. The prime quantity analyzed is anomalous sea surface temperature (SST) in the region 30°S–60°N. Additionally, observed tropical surface wind stress fields were investigated. Further tropical atmospheric information was derived from a multidecadal run with an atmospheric general circulation model that was forced by the same SSTs. The tropical SST variability can be characterized by three modes: an interannual mode the El Niño–Southern Oscillation (ENSO), a decadal mode, and a trend or unresolved ultra-low-frequency variability.

For any valid study of reaction kinetics the phase equilibria involved must be known. We present an apparatus designed to measure both phase equilibria and kinetics for reactions in near-critical water. Liquid−liquid mutual solubilities are reported for the benzene−water and toluene−water systems from 200 to 275 °C at the three-phase pressures and 172 bar. These data were found to be in good agreement with data reported in the literature. Additionally, the near-critical water reaction apparatus was used to verify one-phase regions for the phenol−water and p-cresol−water systems from 250 to 300 °C at 172 bar.

We report successful alkylation reactions in near-critical water in the absence of added acid catalysts. Water has a strong tendency to ionize as the temperature is increased, allowing water in the near-critical region (250−350 °C) to act as an effective acid catalyst. By simultaneously employing near-critical water as the reaction solvent and catalyst, the need for environmentally hazardous organic solvents and acid catalysts is eliminated. The high hydronium ion content of near-critical water proved to be sufficient to synthesize a variety of substituted phenols with tertiary, secondary, and even primary alcohols. The reaction products for each of these reactions are reported.