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報告, Practical report, コロナの世界的な流行によって多くの授業が遠隔で行われることになり，リハビリテーションの専門的な場面で使用する英語を学ぶ授業（ESP）についてもオンラインによる学修方法を模索することとなった．本報告は，大学の言語聴覚学科における必須科目である「入門リハビリテーション英語」の授業に関するその実践報告である．具体的には，遠隔による同時双方型授業の概要とそれに関連する諸活動を振り返りながら検証する．, The dangers associated with the COVID-19 pandemic necessitated a shift to emergency remote teaching for many teachers. Teachers of specialized subjects, such as English for Specific Purposes (ESP), also had to seek and rely on virtual learning solutions. This report provides an overview of the activities conducted as part of the curriculum of Introduction to Rehabilitation English, a university ESP course for speech-language-hearing majors, through a synchronous distance learning environment. It also reflects on and examines online teaching and learning experiences.

A novel microfluidic device that can selectively and specifically isolate exceedingly small numbers of circulating tumor cells (CTCs) through a monoclonal antibody (mAB) mediated process by sampling large input volumes (/=1 mL) of whole blood directly in short time periods (37 min) was demonstrated. The CTCs were concentrated into small volumes (190 nL), and the number of cells captured was read without labeling using an integrated conductivity sensor following release from the capture surface. The microfluidic device contained a series (51) of high-aspect ratio microchannels (35 mum width x 150 mum depth) that were replicated in poly(methyl methacrylate), PMMA, from a metal mold master. The microchannel walls were covalently decorated with mABs directed against breast cancer cells overexpressing the epithelial cell adhesion molecule (EpCAM). This microfluidic device could accept inputs of whole blood, and its CTC capture efficiency was made highly quantitative (97%) by designing capture channels with the appropriate widths and heights. The isolated CTCs were readily released from the mAB capturing surface using trypsin. The released CTCs were then enumerated on-device using a novel, label-free solution conductivity route capable of detecting single tumor cells traveling through the detection electrodes. The conductivity readout provided near 100% detection efficiency and exquisite specificity for CTCs due to scaling factors and the nonoptimal electrical properties of potential interferences (erythrocytes or leukocytes). The simplicity in manufacturing the device and its ease of operation make it attractive for clinical applications requiring one-time use operation.

A 16-channel microfluidic chip with an integrated contact conductivity sensor array is presented. The microfluidic network consisted of 16 separation channels that were hot-embossed into polycarbonate (PC) using a high-precision micromilled metal master. All channels were 40 microm deep and 60 microm wide with an effective separation length of 40 mm. A gold (Au) sensor array was lithographically patterned onto a PC cover plate and assembled to the fluidic chip via thermal bonding in such a way that a pair of Au microelectrodes (60 microm wide with a 5 microm spacing) was incorporated into each of the 16 channels and served as independent contact conductivity detectors. The spacing between the corresponding fluidic reservoirs for each separation channel was set to 9 mm, which allowed for loading samples and buffers to all 40 reservoirs situated on the microchip in only five pipetting steps using an 8-channel pipettor. A printed circuit board (PCB) with platinum (Pt) wires was used to distribute the electrophoresis high-voltage to all reservoirs situated on the fluidic chip. Another PCB was used for collecting the conductivity signals from the patterned Au microelectrodes. The device performance was evaluated using microchip capillary zone electrophoresis (mu-CZE) of amino acid, peptide, and protein mixtures as well as oligonucleotides that were separated via microchip capillary electrochromatography (mu-CEC). The separations were performed with an electric field (E) of 90 V/cm and were completed in less than 4 min in all cases. The conductivity detection was carried out using a bipolar pulse voltage waveform with a pulse amplitude of +/-0.6 V and a frequency of 6.0 kHz. The conductivity sensor array concentration limit of detection (SNR = 3) was determined to be 7.1 microM for alanine. The separation efficiency was found to be 6.4 x 10(4), 2.0 x 10(3), 4.8 x 10(3), and 3.4 x 10(2) plates for the mu-CEC of the oligonucleotides and mu-CZE of the amino acids, peptides, and proteins, respectively, with an average channel-to-channel migration time reproducibility of 2.8%. The average resolution obtained for mu-CEC of the oligonucleotides and mu-CZE of the amino acids, peptides, and proteins was 4.6, 1.0, 0.9, and 1.0, respectively. To the best of our knowledge, this report is the first to describe a multichannel microchip electrophoresis device with integrated contact conductivity sensor array.

This paper presents a novel method for DNA thermal amplification using the polymerase chain reaction (PCR) in an electrokinetically driven synchronized continuous flow PCR (EDS-CF-PCR) configuration carried out in a microfabricated polycarbonate (PC) chip. The synchronized format allowed patterning a shorter length microchannel for the PCR compared to nonsynchronized continuous flow formats, permitting the use of smaller applied voltages when the flow is driven electrically and also allowed flexibility in selecting the cycle number without having to change the microchip architecture. A home-built temperature control system was developed to precisely configure three isothermal zones on the chip for denaturing (95 degrees C), annealing (55 degrees C), and extension (72 degrees C) within a single-loop channel. DNA templates were introduced into the PCR reactor, which was filled with the PCR cocktail, by electrokinetic injection. The PCR cocktail consisted of low salt concentrations (KCl) to reduce the current in the EDS-CF-PCR device during cycling. To control the EOF in the PC microchannel to minimize dilution effects as the DNA "plug" was shuttled through the temperature zones, Polybrene was used as a dynamic coating, which resulted in reversal of the EOF. The products generated from 15, 27, 35, and 40 EDS-CF-PCR amplification cycles were collected and analyzed using microchip electrophoresis with LIF detection for fragment sizing. The results showed that the EDS-CF-PCR format produced results similar to that of a conventional block thermal cycler with leveling effects observed for amplicon generation after approximately 25 cycles. To the best of our knowledge, this is the first report of electrokinetically driven synchronized PCR performed on chip.

The molar excess volume V E has been obtained trough the concentration range at 298.15 K for 41 systems composed of the series of glymes (oxaalkanes), CH 3 –O–(CH 2 –CH 2 –O) m –CH 3 with m =1 to 4 with normal, branched and cyclic alkanes. With literature values, a comprehensive view is given of (a) the change of equimolar V E with the molecular sizes of the components and with alkane structure and (b) concentration dependences which are S-shaped for certain systems. Equimolar H E were obtained at 303.15 K for 43 of the systems and used in applying the Prigogine–Flory (PF) theory to successfully predict the V E features. Evidence for association (Hydrogen bonding) in the pure glymes is reviewed. This accounts for discrepancies between PF theory and experiment which are minor for V E , but major for d V E /d T and C p E as seen through a consideration of literature values of these quantities.

A review is given of the Prigogine-Flory theory and its prediction of the first and second order excess thermodynamic quantities of non-electrolyte mixtures. Effects outside the scope of this theory occur when the mixing process: (1) destroys structure existing in the pure components (orientational order between n-alkane chains, dipolar and quadrupolar order) or (2) creates order in the solution (concentration fluctuations, alcohol multimers, hydrophobic hydration, micelles). These thermodynamic effects are most apparent in the second order quantities. A qualitative interpretation can be given.

Excess molar volumes V E m and excess molar heat capacities C E p ,m have been measured through the composition range for quasi-binaries: [ x {A = c -C 6 H 12 or C 6 H 5 Cl or 1-C 10 H 7 Cl (1-chloronaphthalene)} + (1 - x ) { X CH 3 (CH 2 ) ν 2 - 2 CH 3 + (1 - X )CH 3 (CH 2 ) ν 3 -2 CH 3 }] for ν 2 = 16 or 10 and ν 3 = 7. V E m ( x ) and C E p ,m ( x ) values for the quasi-binaries were fitted by means of empirical equations for each X and also to a ternary correlation equation covering the whole x and X ranges. Two similar tests of Bronsted’s Principle of Congruence have been applied: (1), at x = 0.5, V E m and C E p ,m were plotted against the average alkane carbon number 〈ν〉 = X ν 2 + (1 - x )ν 3 ; these values were consistent, as required by the Principle with those obtained from a mixture of A with a pure alkane of carbon number ν = 〈ν〉; (2), V E m and C E p ,m for (A + n -alkane mixtures of mole fraction X ) were successfully compared, through the x range, with the V E m and C E p ,m for (A + pure alkane) interpolated from literature values to the 〈ν〉 corresponding to the present X . The success of the Principle in the case of V E m and C E p ,m is surprising since these quantities depend, respectively, on liquid “free volume” and alkane “orientational order” which are not obviously the same for a pure alkane and its congruent alkane mixture.

Equimolar values of the excess volume, VE, have been obtained at 25 °C for a series of oxaalkanes, 2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, and 2,5,8,11,14-pentaoxapentadecane, mixed with a series of highly-branched alkanes: 2,2-dimethylbutane, 2,2,4-trimethylpentane, 2,2,4,6,6-pentamethylheptane, and 2,2,4,4,6,8,8-heptamethylnonane. The Prigogine-Flory thermodynamic theory predicts the large variations of VE with the chain-lengths of the molecules in the two series.

Expansion coefficients α, isothermal compressibilities, thermal pressure coefficients γ and heat capacities have been measured at 25°C for the cyclohexane+trans-decalin system. An S-shaped composition dependence, positivelnegative for highllow cyclohexane compositions is found for Cp′E dVE/dT and the thermal expansion contribution to Cp′E namely ΔαγVT. The thermal motion contribution to Cp′E, namely ΔCv is close to zero. The positive excursion of these mixing quantities at high cyclohexane content is anomalous. Correspondingly, the mixing quantity-ΔγVT deviates strongly in this region from the predicted equality with HE. The literature and this work show that all these excess quantities behave similarly for cyclohexane mixed with cyclooctane, methylcyclohexane and some highly branched alkanes. The unusual composition dependence of the thermodynamic quantities is consistent with ‘order’ occurring when any large alkane molecule of globular shape is added to cyclohexane. This is speculatively associated with an interference by the globular alkane with the relatively free rotation of cyclohexane molecules.

Densities and heat capacities of ternary systems were determined at 25°C. The ternary systems consisted of: a polar molecule (component 1) + a mixture of alkanes (components 2 and 3) of different sizes and shapes. Five such systems were studied: chlorobenzene + cyclohexane + n-heptane; chlrobenzene + cyclohexane + n-hexadecane; chlorobenze + cyclohexane + isooctane; chlorobenzene + isooctane + n-heptane; 1-chloronaphthalene + isooctane + n-heptane. The excess molar volumes and heat capacities were obtained along dilution lines by component 1 (chlorobenzene or 1-chloronaphthalene) of mixtures of components 2 and 3 (at fixed component 2 mole fraction X2). Unexpectedly the excess heat capacities C p1(23) E of the pseudo-binaries {1+(2+3)} do not always fall between the two (limiting) curves of C p12 E and C p13 E corresponding to the two binaries {1+2} and {1+3}. Instead, especially for {chlorobenzene + cyclohexane + an n-alkane} the C p1(23) E curves are displaced toward less negative values, even beyond the limiting values corresponding to the binaries. This correlates semi-quantitatively with the negative C p23 E of the binary {2+3}.

Single-molecule detection (SMD) has demonstrated some attractive benefits for many types of biomolecular analyses including enhanced processing speed by eliminating processing steps, elimination of ensemble averaging and single-molecule sensitivity. However, it's wide spread use has been hampered by the complex instrumentation required for its implementation when using fluorescence as the readout modality. We report herein a simple and compact fluorescence single-molecule instrument that is straightforward to operate and consisted of fiber optics directly coupled to a microfluidic device. The integrated fiber optics served as waveguides to deliver the laser excitation light to the sample and collecting the resulting emission, simplifying the optical requirements associated with traditional SMD instruments by eliminating the need for optical alignment and simplification of the optical train. Additionally, the use of a vertical cavity surface emitting laser and a single photon avalanche diode serving as the excitation source and photon transducer, respectively, as well as a field programmable gate array (FPGA) integrated into the processing electronics assisted in reducing the instrument footprint. This small footprint SMD platform was tested using fluorescent microspheres and single AlexaFluor 660 molecules to determine the optimal operating parameters and system performance. As a demonstration of the utility of this instrument for biomolecular analyses, molecular beacons (MBs) were designed to probe bacterial cells for the gene encoding Gram-positive species. The ability to monitor biomarkers using this simple and portable instrument will have a number of important applications, such as strain-specific detection of pathogenic bacteria or the molecular diagnosis of diseases requiring rapid turn-around-times directly at the point-of-use.

Bhargava defined

Systematic changes were made in an Egyptian mummy exhibit gallery, and visitor reactions were assessed. The changes included adding exhibit labels to the wall, changing the physical characteristics of these labels, and introducing a bronze bust reconstructed from a mummified individual. Results demonstrated that several of the factors studied influence label reading: (a) words per label, (b) size of letters, and (c) location of labels. For the most part, label reading facilitated visitor attention to exhibit objects rather than competed for visitor attention. An exception to the facilitation of attention occurred when the mummy cases and the labels were arranged so that visitors had to turn from the label to view the cases (or vice versa). This latter arrangement seemed to produce competition for visitor attention and resulted in shorter viewing times of the mummy cases. Another competing situation occurred when the bronze bust was introduced, apparently diverting attention from label reading to the bust.

The basic assumption of the Flory theory of solution thermodynamics, van der Waals behaviour of the components, is contravened by chlorobenzene and other complex liquids. Their internal pressure decreases, instead of increasing, with decreasing volume. Using chlorobenzene with a series of normal alkanes and four highly branched isomers the following quantities have been measured at 25 °C and equimolar concentration: HE, VE, dVE/dT, dVE/dp, Δ(γVT), CEp, Δ(αγVT) and ΔCv. Against expectation, the Flory theory predicts the main trends of all these data. dVE/dT, Δ(γVT) and CEp for n-Cm systems show deviations from the theory which are readily explained by temperature-sensitive order in the long-chain pure n-Cm liquids. We conclude that the Flory theory remains useful, at least for chlorobenzene, in spite of the breakdown of its van der Waals assumption.

Gas-liquid chromatography (glc) has been used (Xu and Hepler, 1990) to obtain Henry's Law constants and infinite dilution activity coefficients for hydrocarbon and other vapour-phase solutes in two bitumens, Athabasca and Wolf Lake. Thermodynamic interaction between components widely different in molar mass can, however, be characterized by mass-fraction rather than mole-fraction based quantities and by the χ parameter, as has been the practice with polymer systems. The new parameters have been calculated and reveal more unfavorable interactions of the solutes with Wolf Lake than with the Athabasca material. On a utilise la chromatographic gaz—liquide (GLC) (Xu et Hepler, 1990) afin d'obtenir les constantes de la loi d'Henry et les coefficients d'activite de dilution infinie pour des solutes d'hydrocarbures et d'autres solutes en phase vapeur dans deux bitumes, Athabasca et Wolf Lake. Il est toutefois possible de caracteriser l'interaction thermodynamique entre des composants tres differents dans la masse molaire par des grandeurs basees sur la fraction massique pluto't que sur la fraction molaire et par le parametre χ, comme cela est la pratique pour les systemes de polymeres. Les nouveaux parametres ont ete calcules et reveelent des interactions plus deefavorables parmi les solutes composes avec le bitume Wolfe Lake que celui d'Athabasca.

Excess heat capacities, CEp, of oxaalkane (glyme)–dimethylsiloxane systems at 25 °C are reported for 2,5-dioxahexane (monoglyme), 2,5,8-trioxanonane (diglyme), 2,5,8,11-tetraoxadodecane (triglyme) and 2,5,8,11,14-pentaoxapentadecane (tetraglyme) with hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane and octamethylcyclotetrasiloxane, except for tetraglyme with trisiloxane and tetrasiloxane, both incompletely miscible at 25 °C. In addition, CEp was obtained for diglyme mixed with a dimethylsiloxane oligomer corresponding to an average of 15 siloxane segments. W-shaped CEp–composition curves were found for all systems and were attributed to local non-randomness. UCST values were obtained for some systems. Non-randomness was quantified through the concentration–concentration correlation function, Scc=[∂2(G/RT)/∂x2]–1, where G is the solution molar free energy. UCST values were calculated using three models for G, corresponding to the Flory–Huggins combinatorial with interaction between molecular volumes or between molecular surfaces, and a combinatorial due to Prausnitz and collaborators with interaction between surfaces. The last model is best for these systems where there is a large difference in molecular surface/volume ratios. It gives reasonable UCST predictions and a quantitative correlation between the compositions of the maxima in Scc and CEp, as well as a qualitative correlation between the shapes of Scc and CEp curves.

Excess molar heat capacities, CEp, throughout the entire concentration range have been determined at 25 °C for the following oxaalkane–alkane systems: 2,5,8,11,14-pentaoxapentadecane (tetraglyme) with decane, nonane, octane and hexane; 2,5,8,11-tetraoxadodecane (triglyme) with hexadecane, pentadecane, tetradecane, dodecane, decane and hexane; 2,5,8-trioxanonane (diglyme) with 2,6,10,15,19,23-hexamethyltetracosane (squalane), 2,6,10,14-tetramethylpentadecane (pristane), hexadecane and decane; 2,5-dioxahexane (monoglyme) with squalane, pristane, decane and heptane; and 1,4-dioxacyclohexane (p-dioxane) with cyclohexane. For all these tures CEp has a W-shaped concentration dependence (two minima separated by a maximum). By increasing the molecular size of either component, the maximum in CEp is enhanced and displaced towards high concentrations of the smaller component. CEp behaviour correlates with degrees of non-randomness in the mixtures as quantified by the concentration–concentration correlation function Scc which is calculated using the Flory–Huggins theory with a group-interaction model and assuming interaction between molecular surfaces.

Apparent heat capacities have been measured for cyclohexanol and substituted cyclohexanols in dilute n-heptane and n-decane at 25 °C. The alcohols are cyclohexanol, 2-ethylcyclohexanol, 2-tert-butylcyclohexanol, trans-2-phenylcyclohexanol, 2,6-dimethylcyclohexanol, 2,3-dimethylcyclohexanol, 3,4-dimethylcyclohexanol, 3,3,5-trimethylcyclohexanol and 3,3,5,5-tetramethylcyclohexanol. The associational part of the apparent molar heat capacity, ϕc(assoc), shows a maximum against concentration which decreases and moves to higher alcohol concentration as the hydroxyl group on the alcohol becomes increasingly hindered, effectively reducing the self-association capability. A comparison between cyclohexanols and the previously reported phenols (J. Chem. Soc., Faraday Trans., 1991, 87, 1733) indicates that cyclohexanols show a higher ability to self-associate owing to the larger flexibility of the cyclohexanol ring as compared to the rigid aromatic ring. Treszczanowicz–Kehiaian theory for associated liquids was used to obtain the volumetric equilibrium constants and the enthalpy change for the formation of hydrogen bonds, ΔH0. For cyclohexanols ΔH0 is higher than for the corresponding phenols. As with the phenols, the tetramer population is severely reduced, dimers and trimers being more important.

A general discussion on the effect of steric hindrance and π electrons on the self-association of linear, branched, cyclic, aromatic and phenolic alcohols in inert solvents is presented. A relation between the self-association ability of an alcohol and its molecular geometry is proposed using as a measure of the steric hindrance the ratio (q) of the polar surface area of the alcohol to the polar surface area of a linear alcohol. Surface areas were calculated using a molecular-mechanics program. The ratio q correlates with the free energy for tetramer formation and is a good measure of the local steric hindrance on the hydroxyl caused by groups in its immediate neighbourhood. The effect of π electrons on self-association was studied through quantum-mechanical calculations (MNDO), providing an explanation for the experimental finding that the enthalpy for hydrogen-bond formation for phenolic alcohols is systematically smaller than for any other type of alcohol. The MNDO results indicate that for any alcohol whose hydroxyl group is directly attached to the aromatic ring the electron density in the oxygen atom is small and hence phenolic alcohols form weak hydrogen bonds. Values of the enthalpy and entropy for hydrogen-bond formation are correlated and almost compensate for the alcohols.

The apparent molar heat capacity, phi-c, its associative part, phi-c(assoc), and the excess heat capacity, C(p)E, have been obtained at 25-degrees-C through the concentration range for methanol, hexan-1-ol and decan-1-ol in a series of proton acceptor solvents: methyl acetate, ethyl acetate, octyl acetate, methyl octanoate, decyl acetate and methyl tetradecanoate. The results are explained quantitatively by the Tresczanowicz-Kehiaian (TK) association model and the Flory lattice model in terms of alcohol self-association into tetramers, characterized by an OH-OH equilibrium constant and enthalpy, and by alcohol-ester complex formation characterized by an OH-COO equilibrium constant and enthalpy, each independent of alcohol and ester chain length. As predicted, phi-c(assoc) at infinite alcohol dilution is independent of the choice of alcohol, but increases with increasing ester chain length. With increasing alcohol concentration phi-c(assoc) passes through a maximum which is much reduced compared with the inert solvent case. For each alcohol, C(p)E increases with increasing ester chain length, while for the same ester, C(p)E decreases with increasing alcohol chain length. dC(p)E/dT is positive for mixtures of methanol and methyl acetate, as predicted by the TK model. It is negative for decanol with methyl acetate, contrary to the TK model, but consistent with a non-random distribution of alcohol tetramers in the solution.

The excess heat capacity, [Formula: see text], has been measured through the concentration range at 25 °C for cyclohexane + Si(OR)4 where R = methyl (Me), ethyl (Et), propyl (Pr), and butyl (Bu). [Formula: see text] is negative and concave upward for the last three oxysilanes. For R = Me [Formula: see text] has a region of zero curvature, which, on reducing T to 2 °C, becomes concave downward, i.e., its concentration dependence becomes W-shaped. [Formula: see text] has also been obtained at 15 °C for Si(OMe)4 mixed with the following hydrocarbons of increasing molecular size: cyclooctane, cis-decalin, dicyclohexyl, n-hexadecane, 2,2,4,4,6,8,8-heptamethylnonane, 2,6,10,14-tetramethylpentadecane, and 2,6,10,15,19,23-heptamethyltetracosane (at 25 °C). All [Formula: see text] values for these systems present a W-shape, which, with increasing hydrocarbon size becomes increasingly pronounced and moves to lower hydrocarbon concentration. [Formula: see text] behaviour correlates with degrees of non-randomness in the systems as quantified by the concentration–concentration correlation function Scc which is predicted using the Flory–Huggins theory with a group-interaction model and assuming interaction between molecular surfaces. Differences between [Formula: see text] for n-C16 and highly branched C16 isomer, 2,2,4,4,6,8,8-heptamethylnonane, are attributed to liquid state orientational order and higher molecular surface/volume ratio for the normal isomer. Keywords: excess heat capacity, W-shape, non-randomness, hydrocarbons, tetraalkylsiloxanes.

The excess heat capacity CpE has been measured and the concentration-concentration correlation function Scc has been calculated from literature GE and HE values for nitroethane+cyclohexane at 35, 30, 27 and 25 °C, approaching the UCST of 23.3 °C. CEp has a W-shaped concentration dependence, i.e. two negative minima separated by a positive maximum which becomes progressively larger and sharper as the temperature is lowered, attaining 15 J K−1 mol−1 at 25 °C. The Scc, a measure of solution non-randomness, has a sharp positive maximum whose temperature behaviour parallels that of CEp . A Flory-Huggins-theory expression for Scc gives results which are qualitatively, but not quantitatively, in agreement with experimental .Scc values, the difference being due to an incorrect rendering of the concentration dependence of HE approaching the UCST. 1-Nitropropane+cyclohexane at 25 °C also gives a W-shaped CEp with a small positive maximum of 3 J K−1 mol−1, consistent with a small maximum in Scc, obtained from GE, and a UCST

Vapour-liquid equilibrium at 308.15 K, heats of mixing, heat capacities and densities at 298.15 K have been measured for methanol + 1,1,2-trichlorotrifluoroethane (Freon 113). In addition to the clearly dominant role of alcohol self-association, there are also indications of a weak specific interaction between methanol and Freon molecules. Three simple models of athermal association, which exclude lower multimers, have been used to predict gE, hE, cEP and the apparent heat capacity of methanol, φc,1: (1) Mecke-Kempter and (2) Kretschmer-Wiebe type models of continuous association of the alcohol starting with the tetramerization, and (3) a model considering only the tetramerization. The models perform reasonably well for methanol + Freon 113 and methanol + n-hexane mixtures. However, it appears that the continuous association models systematically overestimate the chemical part of hE, whereas the tetramerization-only model underestimates the chemical part of gE. When the models are extended to include complex formation between methanol and Freon, some of the experimental indications of the non-inert behaviour of Freon 113 can be predicted. The importance of the physical contribution to the excess functions is discussed and the magnitude of gE(phys) is estimated independently of the association models used. If amended by the physical contribution, both continuous association models yield an excellent prediction of gE.

X-ray transition radiation can be used to measure the Lorentz factor of relativistic particles. Standard transition radiation detectors (TRDs) typically incorporate thin plastic foil radiators and gas-filled x-ray detectors, and are sensitive up to \gamma ~ 10^4. To reach higher Lorentz factors (up to \gamma ~ 10^5), thicker, denser radiators can be used, which consequently produce x-rays of harder energies (>100 keV). At these energies, scintillator detectors are more efficient in detecting the hard x-rays, and Compton scattering of the x-rays out of the path of the particle becomes an important effect. The Compton scattering can be utilized to separate the transition radiation from the ionization background spatially. The use of conducting metal foils is predicted to yield enhanced signals compared to standard nonconducting plastic foils of the same dimensions. We have designed and built a Compton Scatter TRD optimized for high Lorentz factors and exposed it to high energy electrons at the CERN SPS. We present the results of the accelerator tests and comparisons to simulations, demonstrating 1) the effectiveness of the Compton Scatter TRD approach; 2) the performance of conducting aluminum foils; and 3) the ability of a TRD to measure energies approximately an order of magnitude higher than previously used in very high energy cosmic ray studies., Comment: 10 pages, 4 figures, To be published in NIM

We are currently developing miniaturized, chip-based electrophoresis devices fabricated in plastics for the high-speed separation of oligonucleotides. One of the principal advantages associated with these devices is their small sample requirements, typically in the nanoliter to sub-nanoliter range. Unfortunately, most standard sample preparation protocols, especially for oligonucleotides, are done off-chip on a microliter-scale. Our work has focused on the development of capillary nanoreactors coupled to micro-separation platforms, such as micro-electrophoresis chips, for the preparation of sequencing ladders and also polymerase chain reactions (PCRs). These nanoreactors consist of fused-silica capillary tubes (10-20 cm x 20-50 microns I.D.) with fluid pumping accomplished using the electroosmotic flow generated by the tubes. These reactors were situated in fast thermal cyclers to perform cycle sequencing or PCR amplification of the DNAs. The reactors could be interfaced to either a micro-electrophoresis chips via capillary connectors micromachined in polymethylmethacrylate (PMMA) using deep X-ray etching (width 50 microns; depth 50 microns) or conventional capillary gel tubes using zero-dead volume glass unions. For our chips, they also contained an injector, separation channel (length 6 cm; width 30 microns; depth 50 microns) and a dual fiber optic, near-infrared fluorescence detector. The sequencing nanoreactor used surface immobilized templates attached to the wall via a biotin-streptavidin-biotin linkage. Sequencing tracks could be directly injected into gel-filled capillary tubes with minimal degradation in the efficiency of the separation process. The nanoreactor could also be configured to perform PCR reactions by filling the capillary tube with the PCR reagents and template. After thermal cycling, the PCR cocktail could be pooled from multiple reactors and loaded onto a slab gel or injected into a capillary tube or microchip device for fractionation.

We are currently developing miniaturized, chip-based electrophoresis devices fabricated in plastics for the high speed separation of oligonucleotides. One of the principal advantages associated with these devices is their small sample requirements, typically in the nanoliter to sub-nanoliter range. Unfortunately, most standard sample preparation protocols, especially for oligonucleotides, are done off-chip on a microliter-scale. Our work has focused on the development of capillary nano-reactors coupled to micro-separation platforms, such as micro-electrophoresis chips, for the preparation of sequencing ladders and also, PCR reactions. These nano-reactors consist of fused silica capillary tubes (length equals 10 - 20 cm; id equals 20 - 50 micrometer) with fluid pumping accomplished using the electro-osmotic flow generated by the tubes. These reactors were situated in fast thermal cyclers to perform cycle sequencing or PCR amplification of the DNAs. The reactors were interfaced to the micro-electrophoresis chips via capillary connectors micromachined in polymethylmethacrylate (PMMA) using deep X- ray etching (width equals 50 micrometer; depth equals 50 micrometer) and were situated directly on the PMMA-based microchip. This chip also contained an injector, separation channel (length equals 6 cm; width equals 30 micrometers; depth equals 50 micrometers) and a dual fiber optic, near- infrared fluorescence detector. The sequencing nano-reactor used surface immobilized templates attached to the wall via a biotin:streptavidin:biotin linkage produced by PCR using a biotinylated forward primer. Sequencing tracks could be directly injected into gel-filled capillary tubes with minimal degradation in the efficiency of the separation process. The nano-reactor could also be configured to perform PCR reactions by filling the capillary tube with the PCR reagents and template. After thermal cycling, the PCR cocktail could be injected into a capillary tube or a micro-chip device for fractionation. In all cases, the detection of the oligonucleotides was accomplished using ultra-sensitive near- IR fluorescence detection.

The molar excess heat capacity (CEp) has been obtained through the concentration range at 25 °C for mixtures of alkan-1-ols: methanol with butanol, hexanol and decanol and decanol with butanol and hexanol. CEp is negative and small, increasing in magnitude with difference in chain length of the alkan-1-ols to a maximum of –3 J mol–1 K–1 for methanol–decanol. CEp has also been measured at 25 °C for methanol and other alkanols mixed with iso-, sec- and tert-butyl alcohol (I), 2-methylbutan-2-ol (II), 3-methylpentan-3-ol (III) and 3-ethyl-pentan-3-ol (IV). With increasing steric crowding of the tertiary OH, CEp becomes extremely large, –18 J mol–1 K–1 for methanol–IV at equimolar concentration, the apparent molar Cp of methanol in IV being negative at low concentration. The negative CEp(x) for methanol–I is of normal positive curvature, but with II, CEp has a W-shaped concentration dependence exhibiting two regions of positive CEp(x) curvature separated by a region of negative curvature. An extension of the Treszczanowicz–Kehiaian association model has been made to alcohol–alcohol mixtures with consideration of multimers mainly confined to linear tetramers. Assuming equal enthalpies and equilibrium constants for H-bonding between like alkan-1-ols (AA and BB) and between unlike alkanols (AB) leads to positive CEp predictions. The experimental negative CEp values are associated with a lowering of the equilibrium constant for H-bond formation in the alkan-1-ol with increasing chain length coupled with relatively stronger AB bonding. The equilibrium constant, KBB, for H-bonding between tertiary alcohol hydroxyls is found to be lowered by steric crowding of the tertiary hydroxyl, raising the Cp of the pure liquid. The constant, KAB, for bonding between primary (A) and tertiary (B) hydroxyls in the multimer chain is less affected by the tertiary crowding resulting in lower solution Cp and large negative CEp. The S- and W-shape concentration dependences require modifications of KAB owing to the proximity in the tetramer chain of either A or B alcohols resulting in an effective concentration dependence of KAB.

The classical free-energy expression for a polymer solution with Flory–Huggins (FH) combinatorial together with an interaction free energy reflecting component molecular volumes predicts that as the polymer molecular weight M→∞, the polymer critical composition ϕ2c→ 0 and the critical temperature Tc→θ, the Flory temperature. Experimental evidence indicates that molecular surfaces should replace molecular volumes in the interaction term. This model leads to limiting ϕ2c and Tc values which can differ widely from zero and θ, respectively, when the surface/volume ratio of the polymer is less than ⅔ that of the solvent, as found for many systems. The new predictions are contrary to many experimental data. Replacement of the FH combinatorial by the multiple-connected combinatorial of Prausnitz and collaborators restores the usual limiting values of ϕ2c and Tc for polymer solutions constituting experimental evidence for this combinatorial.

Literature excess-volume (VE) data for n-alkane mixtures have been found to obey an extended corresponding-states principle for chain molecules which is then used to predict VE as a function of composition and temperature for a wide variety of n-alkane systems. Results are excellent and superior to those obtained with other treatments.

Order-destruction and order-creation during mixing are discussed for binary mixtures of various liquids (component 1) with the n -alkane series (component 2). When component 1 is a spherical molecule liquid, e.g. cyclohexane, anomalous positive contributions occur in H E and S E , but negative ones occur in C P E , Δ C V , d V E /d T and other second-order quantities. The Flory theory is used as a first approximation to the prediction of these quantities. Thermodynamic effects, not included in the theory, are attributed to a net decrease in structure during mixing because of a destruction of short-range correlations of molecular orientations (CMO) in pure n -C n . When component 1 is a plate-like molecule, e.g. 1-chloronaphthalene, these effects are decreased and reversed in sign. This has been ascribed to a net increase in structure because of a hindrance to molecular motion or a change in molecular conformation. When component 1 is a linear or branched alcohol, the n -C n are relatively inert while component 1 is associated in both the pure and solution states leading to positive or negative effects in C P E depending whether the solution or pure component 1 is more structured. The Treszczanowicz-Kehiaian model for self-associated liquids + inert solvents explains these results and also provides a general framework for the discussion of both the process of order-creation and the process of order-destruction in solution.

The excess heat capacity (CEp) has been measured for acetone + 2,2,4,4,6,8,8-heptamethylnonane (br-C16) (10 and 25°C), +n-C12 (15 and 25°C) and +n-C6 (25°C). CEp is large and positive but becomes negative at both extremes of the concentration range, i.e. it is W-shaped. It becomes rapidly more positive on loweringT, approaching phase separation at the UCST. br-C16 mixed with 2-butanone, 3-hexanone, 4-heptanone and 5-nonanone also give W-shapedCEp(x) curves although the negativeCEp appearing at very high ketone mole fraction (0.95) are extremely small, less than 0.05 J K−1 mol−1. As the length of the ketone molecule is increased, the W-shape becomes less pronounced and has disappeared for br-C16 + 4-decanone where CEp is negative throughout the composition range. The present systems, which show W-shapeCEp, and those in the literature, have large equimolarHE values, ⋍ 1000 J mol−1 or larger, and often are close to phase separation. It is suggested that the W-shape arises from twoCEp contributions. One is negative and of parabolic concentration dependence. The other, due to non-randomness and associated with extremely largeHE and GE values, is shown by the Guggenheim quasi-chemical theory to be positive, concave downwards in the middle of the composition range, but concave upwards at the extremes, i.e. it has the correct concentration dependence to give the W-shape. The excess volume has been measured for acetone + br-C16, +n-C12 and +n-C6. It is large and positive while dVE/dT, for systems near the UCST, is more positive than predicted by the Flory theory, i.e. its behavior is analogous to CEp. It is suggested that: (1) polar (but not H-bonded) systems where HE is very large, ⋍ 1000 J mol−1 or larger should exhibit the W-shapeCEp, becoming more pronounced with decrease of temperature, and (2) the curvature of HE/x1x2 againstx should be positive and large, increasing with decreasingT.

When applied to systems containing a polar component, the Flory theory with X12, fitted to HE often predicts VE values which are much too large.This seems to be due to self-association of the polar molecules requiring use of a theory which takes this into account.

Infrared vibration—rotation spectra have been obtained for DCl and CO in a variety of cyclic and bicyclic alkanes and in alkyl-substituted cyclopentanes and cyclohexanes. The band shapes for CO depend on solvent free volume. For DCl they are sensitive to solvent structure, the rotation being perturbed by surface features (“roughness”) of the surrounding molecules. Molecular roughness is assessed qualitatively either through inspection of molecular models or through V*, the solvent volume at close-packing, obtained from equation of state data.

Using a Sodev vibrating-tube densimeter the excess molar volumes were measured for cyclopentane + one of five hexanes or + one of eight heptanes) at 298.15 K. The V m E 's show a consistent trend towards more negative values when the number of methyl groups increases correlating well with the cohesive energy density. The Flory theory was tested with respect to its ability to reflect such a behaviour.

The Rayleigh ratio has been obtained for the following mixtures of non-electrolytes that show “w-shape” CEp vs. x curves: Nitrobenzene + n-Heptane, 1,4-Dichlorobutane + n-Heptane and Acetone + n-Dodecane. From them, the concentration-concentration correlation function Scc(0) has been calculated, as well as the excess Gibbs energy. It has been found that a clear tendency to homocoordination is present in all the mixtures studied. There is a rough correspondence between the concentration at which the maximum of the Scc(0) curves occur and those at which the negative curvature regions exist in the CEp curves. Also the larger the value of max. Scc(0) the more intense the “w-shape” effect. Despite size differences between the components and specific interactions which complicate the connection between Scc(0) and CEp, an analysis in terms of simple mean field models supports the view that the systems which show “w-shape” CEp curves still feel the effects of the more or less distant UCST. Hence Scc(0) is proposed as an indicator of the “w-shape” CEp.

The heat of mixing ΔHM has been obtained as a function of composition for nematic p-methoxybenzylidine-p-n-butylaniline (MBBA) at 25°C with two pairs of normal and branched alkane isomers (n-octane and 2,2,4-trimethylpentane (TMP), n-hexadecane and 2,2,4,4,6,8,8-heptamethylnonane (HMN)) and with cyclohexane, toluene, and carbon tetrachloride. Heats of mixing were also obtained at 55°C for isotropic MBBA with n-hexadecane, HMN, and toluene. The composition dependence of ΔHM is strongly skewed toward high MBBA concentration for systems containing nematic MBBA, and less so for those containing MBBA in the isotropic state. Heats of solution ΔHS at a low volume fraction (0.08) of MBBA were measured between 25°C and 75°C in the above seven solvents. The ΔHS values change rapidly with temperature in both the nematic and isotropic temperature ranges with a small discontinuity at 43°C, the nematic-isotropic transition temperature. The data indicate: (1) a strongly temperature-dependent orientational order in pure MBBA, of long range in the nematic phase and of short range in the isotropic phase, (2) a correlation of orientations of MBBA molecules with n-alkane chains and with toluene, but not with the branched alkane molecules or cyclohexane.

Using the Picker flow microcalorimeter, excess heat capacities have been obtained at 25°C throughout the concentration range for 2,2-dimethylbutane,n-hexane, and cyclohexane each mixed with a series of hexadecane isomers of increasing degrees of orientational order, as determined by depolarized Rayleigh scattering. The isomers are 2,2,4,4,6,8,8-heptamethylnonane, 6-, 4-, and 2-methylpentadecane, andn-hexadecane. Thec values are negative, increasing rapidly in magnitude with increase of orientational order, and are not predicted by the Prigogine—Flory theory which neglects order. Values ofc are obtained at 10, 25, and 55°C for cyclohexane +6-, 4-, and 2-methylpentadecane which with other literature data lead to the temperature dependence of the thermodynamic excess functions for cyclohexane solutions of the five C16 isomers. The excess enthalpy and entropy vary with the C16 isomer and with temperature, but the corresponding variation of the excess free energy is small, indicating a high degree of enthalpy-entropy compensation. This is consistent with a rapid decrease with temperature of orientational order in the C16 isomers.

Depolarized Rayleigh scattering has been used to obtain values of the molecular optical anisotropy (γ2) for the following hexadecane isomers at high dilution in carbon tetrachloride : 2,2,4,4,6,8,8-heptamethylnonane, 6-, 4- and 2-methylpentadecane, 6-pentylundecane and n-hexadecane. The values increase moderately through the series corresponding to increasingly anisotropic molecular shapes. Values of γ2 have also been obtained for the hexadecane series in their pure liquid states. These increase rapidly relative to the dilute solution values, indicating the development of short-range orientational order or correlations of molecular orientations. The pure liquid results with 6-, 4- and 2-methylpentadecane show that orientational order depends strongly on the methyl position and length of the straight-chain part of the alkane molecule. Values of γ2 for the hexadecane isomers have been found for high dilution in cyclohexane, 2,2-dimethylbutane and n-hexane which indicates that the hexadecanes can correlate their orientations to only a limited extent with these hexane solvents. Heats of mixing have been measured at 25°C through the concentration range for the hexadecane isomers mixed with cyclohexane, 2,2-dimethylbutane and n-hexane. For each hexane, the heats increase through the series of hexadecane isomers. This corresponds to the increase of orientational order in the pure hexadecane isomers and the destruction of order in the hexadecane on mixing with the hexane. The magnitudes and concentration dependences of the heats for the n-C6+ C16 isomer systems are similar to those for n-C6+ n-C16 heats at different temperatures. This is explained by changing temperature having the same effect on the order of n-C16 as changing molecular shape on the order of the C16 isomers at 25°C.

Excess heat capacities, CEp have been obtained through the concentration range at 25°C for five sets of systems of type An + B: hexafluorobenzene + 2,2,4-trimethylpentanc and 2,2,4,4,6,8,8-heptamethylnonane; hexafluorobenzene + cyclohexane (10° W) and dicyclohexyl (W); 1-chloronaphthalene + 2,2-dimethylbutane, 2,2,4-trimethylpentane (W) and 2,2,4,4,6,8,8-heptamethylncnane (W), 1-chloronaphthalene + n-hexadecane; 1-chloronaphthalene + cyclohexane and dicyclohexyl (15°, W). For the systems indicated, CEp has a W-shape, i.e., two minima separated by a maximum or two changes of sign of the curvature. The W-shape does not occur for hexafluorobenzene + cyclohexane at 25° but appears at 10°. Temperature and molecular size act on CEp through the degree of solution non-randomness as indicated by GE and the concentration-concentration correlation function, Scc which is a good predictor for the W-shape and of the concentration at which the maximum appears. The W-shape corresponds to an Scc value greater than 0.7 and GE > 800 J mol−1, the temperature being within 100 K of the UCST.

Systems exhibiting large H E and G E and within ~100 K of the UCST show a W-shape concentration dependence in C p E which is ascribed to two contributions: a “normal”, random C p E of negative sign and a positive non-random C p E . Approaching the LCST, the W-shape should be found when the LCST is due to a large free volume difference between the components but not for an aqueous system LCST. As with C p , other second-order quantities such as α p and K T tend to infinity at T C . It appears that a W-shape d V E d P would be discernible only for T less than a degree from T C . Both random and non-random contributions to d V E d T have the same sign and hence the W-shape should not be found. Experimental d V E d T results were discussed in terms of the Flory theory. The discrepancy observed between experimental and predicted values near the UCST is associated with non-random contributions to d V E d T .

The infrared spectra of DCl dissolved in a large number of branched and normal liquid alkanes have been related to structural properties of these solvents. Both the free volume and the shape of the alkane molecule have direct effects on the form of the vibration-rotation fundamental of the DCl solute. The results are analyzed using a correlation function approach and some calculations of molecular torque are reported.