bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Analysis of Mesenteric and Peripheral Blood Circulating Tumor DNA in Colorectal Cancer Patients
Authors: TABACK BRET , SAHA SUKAMAL , HOON DAVE S. B.
Published: November 2006

Abstract:  An increasing number of reports have demonstrated the presence of tumor‐specific DNA in cancer patients' plasma/serum. These findings offer the prospective of serologic tumor markers that may aide in early disease detection, predict subclinical disease progression, and monitor treatment responses. However, for patients with colorectal cancer (CRC), there are few reports using this approach, with most revealing poor sensitivity. In contrast to tumors of other organ systems, CRCs drain predominantly via the mesenteric/portal veins (MV) to the liver. We hypothesize that because of this unique relation, tumor DNA may be less abundant in CRC patients' systemic circulation as compared to the mesenteric/portal system. At the time of surgery, paired blood was collected from both the peripheral vein (PV) and MV from 33 CRC patients. DNA was isolated from serum, quantified and assessed for loss of heterozygosity (LOH) using a panel of 11 microsatellite markers corresponding to regions on six chromosomes frequent for LOH in CRC. In addition, 16 samples were assessed for the presence of hypermethylated DNA for tumor suppressor genes:

MGMT

,

P16

,

RAR‐β2

,

RASSF1A

, and

APC

. Circulating tumor DNA associated with LOH or methylation was more frequently detected in the MV of patients, 11 (33%) and 6 (38%), as compared to PV, 9 (27%) and 1 (6%), respectively. This study is the first to identify the presence of increased tumor DNA in the direct efferent venous drainage system of CRC and its variation as compared to systemic circulation. The findings provide important evidence supporting the origin of tumor‐associated DNA in circulation, which merits consideration when devising blood‐based nucleic acid assays for the assessment of CRC.
Optimized Real‐Time Quantitative PCR Measurement of Male Fetal DNA in Maternal Plasma
Authors: ZIMMERMANN BERNHARD G. , HOLZGREVE WOLFGANG , AVENT NEIL , HAHN SINUHE
Published: November 2006

Abstract:  DNA of fetal origin is present in the plasma of pregnant women. The quantitative measurement of circulatory fetal DNA (cfDNA) by real‐time quantitative PCR (qPCR) has been applied to investigate a possible correlation between increased levels and pregnancy‐related disorders. However, as the levels of cfDNA are close to the detection limit (LOD) of the method used, the measurements may not be reliable. This is also problematic for the evaluation of preanalytical steps, such as DNA extraction and cfDNA enrichment by size separation. We optimized a protocol for the qPCR analysis of the multi‐copy sequence DYS14 on the Y chromosome. This was compared with an established assay for the single‐copy SRY gene. Probit regression analysis showed that the limit of detection (LOD) of the DYS14 assay, (0.4 genome equivalents (GE)) and limit of quantification (LOQ) were 10‐fold lower in comparison to SRY (4 GE). The levels of cfDNA obtained from the first trimester of pregnancy could be quantified with high precision by the DYS14 assay (CV below 25%) as opposed to the SRY measurements (26–140%). Additionally, fetal sex was correctly determined in all instances. The low copy numbers of fetal DNA in plasma of women in the first trimester of pregnancy can be measured reliably, targeting the DYS14 that is present in multiple copies per Y chromosome.
Intrinsic ON Responses of the Retinal OFF Pathway Are Suppressed by the ON Pathway
Authors: Rentería René C. , Tian Ning , Cang Jianhua , Nakanishi Shigetada , Stryker Michael P. , Copenhagen David R.
Published: November 2006

Parallel ON and OFF pathways conduct visual signals from bipolar cells in the retina to higher centers in the brain. ON responses are thought to originate by exclusive use of metabotropic glutamate receptor 6 (mGluR6) expressed in retinal ON bipolar cells. Paradoxically, we find ON responses in retinal ganglion cells of mGluR6-null mice, but they occur at long latency. The long-latency ON responses are not blocked by metabotropic glutamate or cholinergic receptor antagonists and are not produced by activation of receptive field surrounds. We show that these longer-latency ON responses are initiated in the OFF pathways. Our results expose a previously unrecognized intrinsic property of OFF retinal pathways that generates responses to light onset. In mGluR6-null mice, long-latency ON responses are observed in the visual cortex, indicating that they can be conducted reliably to higher visual areas. In wild-type (WT) mice, APB (dl-2-amino-4-phosphonobutyric acid), an mGluR6 agonist, blocks normal, short-latency ON responses but unmasks longer-latency ones. We find that these potentially confusing ON responses in the OFF pathway are actively suppressed in WT mice via two pharmacologically separable retinal circuits that are activated by the ON system in the retina. Consequently, we propose that a major function of the signaling of the ON pathway to the OFF pathway is suppression of these mistimed, and therefore inappropriate, light-evoked responses.
The c-Jun N-Terminal Kinase Activator Dual Leucine Zipper Kinase Regulates Axon Growth and Neuronal Migration in the Developing Cerebral Cortex
Authors: Hirai Syu-ichi , Feng Cui De , Miyata Takaki , Ogawa Masaharu , Kiyonari Hiroshi , Suda Yoko , Aizawa Shinichi , Banba Yumi , Ohno Shigeo
Published: November 2006

Mammalian corticogenesis substantially depends on migration and axon projection of newborn neurons that are coordinated by a yet unidentified molecular mechanism. Dual leucine zipper kinase (DLK) induces activation of c-Jun N-terminal kinase (JNK), a molecule that regulates morphogenesis in various organisms. We show here, using gene targeting in mice, that DLK is indispensable for establishing axon tracts, especially those originating from neocortical pyramidal neurons of the cerebrum. Direct and quantitative analysis of radial migration of pyramidal neurons using slice culture and a time-lapse imaging system revealed that acceleration around the subplate was affected by DLK gene disruption and by administration of a JNK inhibitor. Phosphorylation of JNK substrates, including c-Jun and doublecortin, and of JNK itself at the activation loop were partially affected in brains of DLK-deficient mouse embryos. These data suggest that DLK plays a significant role in the coordinated regulation of radial migration and axon projection by modulating JNK activity.
Primary Afferent NMDA Receptors Increase Dorsal Horn Excitation and Mediate Opiate Tolerance in Neonatal Rats
Authors: Zeng Jinsong , Thomson Lisa M. , Aicher Sue A. , Terman Gregory W.
Published: November 2006

Repeated exposure to opiates produces analgesic tolerance, which limits their clinical usefulness. Whole-cell voltage-clamped lamina I cells in spinal slices from opiate-tolerant neonatal rats show an increase in miniature, spontaneous, and primary afferent-evoked EPSCs when compared with lamina I cells from opiate-naive rat spinal slices. This increased excitation can be blocked by the NMDA receptor (NMDAR) antagonist APV, apparently acting at NMDARs on primary afferents. Consistent with these results, electron microscopy demonstrates an increased incidence of NMDARs in substance P-containing spinal dorsal horn primary afferent terminals in opiate-tolerant rats. Moreover, superfusion of spinal slices from opiate-tolerant rats with NMDA produces a reversible increase in miniature EPSC (mEPSC) frequency in contrast to a decrease in mEPSC frequency produced by NMDA in opiate-naive slices. Finally, NMDAR antagonists inhibit the expression of opiate tolerance both in inhibiting EPSCs in spinal slices and in inhibiting behavioral nociceptive responses to heat.

NMDAR antagonists have been reported in many studies to inhibit morphine analgesic tolerance. Our studies suggest that an increase in primary afferent NMDAR expression and activity mediates a hypersensitivity to noxious stimuli and causes the inhibition of opiate efficacy, which defines tolerance.
A Single Mechanism Can Explain the Speed Tuning Properties of MT and V1 Complex Neurons
Authors: Perrone John A.
Published: November 2006

A recent study by Priebe et al., (2006) has shown that a small proportion (27%) of primate directionally selective, complex V1 neurons are tuned for the speed of image motion. In this study, I show that the weighted intersection mechanism (WIM) model, which was previously proposed to explain speed tuning in middle temporal neurons, can also explain the tuning found in complex V1 neurons. With the addition of a contrast gain mechanism, this model is able to replicate the effects of contrast on V1 speed tuning, a phenomenon that was recently discovered by Priebe et al., (2006). The WIM model simulations also indicate that V1 neuron spatiotemporal frequency response maps may be asymmetrical in shape and hence poorly characterized by the symmetrical two-dimensional Gaussian fitting function used by Priebe et al., (2006) to classify their cells. Therefore, the actual proportion of speed tuning among directional complex V1 cells may be higher than the 27% estimate suggested by these authors.
A New Quantitative Procedure to Determine the Location and Embedment Depth of a Void Using Surface Waves
Authors: Nasseri-Moghaddam Ali , Cascante Giovanni , Hutchinson Jean
Published: November 2006

Detecting underground cavities beneath construction sites and urban areas is a crucial task for many engineering projects. Each year, subsidence and surface soil failure due to underground voids cause substantial damage around the world. Most of the seismic methods currently used for cavity detection can successfully locate a void but not its embedment depth. In spite of successful case histories, void detection is still a challenging problem because of the lack of a standard, quantitative void-detection technique. In addition, existing non-destructive techniques do not consider the effect of lateral inhomogeneities, i.e., cavities, in the wave propagation. Thus, the detection of underground cavities needs further study. This paper presents the results of numerical simulations of the multi-channel analysis of surface waves (MASW) in a laterally non-homogeneous medium. First, the Lamb solution is used to calibrate a homogeneous model, subsequently, voids with different dimensions and embedment depths are included in the medium. Analysis of the resulting surface responses shows that time and frequency domain parameters are sensitive to the location, embedment depth, and size of voids; which interact with the incoming wave front causing reflection of Rayleigh waves and strong attenuation of transmitted waves. The power-spectral-density functions clearly show patterns of attenuation and amplification. The authors propose a new analysis procedure to determine not only the location but also embedment depth of a void; this procedure is based on the attenuation analysis of Rayleigh waves (AARW). The new method uses the frequency spectra of recorded signals to compute a spectral-energy parameter and a modified logarithmic-decrement parameter. Numerical results of the AARW method applied to different conditions, including noisy signals, show that these parameters indicate successfully the location and embedment depth of underground voids.
MASW, The Wave of the Future Editorial
Authors: Crice Doug
Published: November 2006

Revolutionary innovations in geophysical methods develop when instruments, techniques, or software evolve to make them possible. A few of these cause dramatic changes in the types of surveys and analysis done. Past examples were shallow reflection surveys and scanning resistivity pseudo-sections. The author believes that surface wave surveys will cause a similar, perhaps extraordinary paradigm shift in geophysics because of the usefulness and interpretability of the data, and the potential for dramatically higher productivity.
Cavity Detection Using Single-fold Frequency Analysis Editorial
Authors: Cull James , Jung George , Massie Duncan
Published: November 2006

A 4-channel, single-fold seismic acquisition system can be used to measure frequency domain response along paved roads. Shallow membrane delaminations and voiding defects are identified by a dominant mode consistent with membrane vibration and high-frequency attenuation above [Formula: see text]. The results correlate well with GPR profiles, and are especially useful for near-surface imaging where metallic clutter noise corrupts EM measurements.
Resolution of High-frequency Rayleigh-wave Data
Authors: Xia Jianghai , Chen Chao , Tian Gang , Miller Richard D. , Ivanov Julian
Published: November 2006

It is essential to understand the potential resolving power of surface wave data in interpreting inverted vertical (layered 1D) and horizontal (‘pseudo-2D’) shear (S)-wave velocity models. The model resolution matrix indicates that the S-wave velocity model of a layered earth model can be perfectly resolved in a least-squares sense if error-free data are inverted. However, we show that errors in real data introduce a smear matrix in the least-squares solution, reducing the resolution of an S-wave velocity model. A field test shows how accurate dispersion curves can resolve a low velocity layer of about 25% contrast at [Formula: see text] depth below a stiff overburden. The horizontal resolution of surface wave surveys is limited to the aperture (length) of the recording array. In phase velocity measurements, the layered model estimate represents an average over this length. Any lateral discontinuities introduce a systematic error into the inversion, leading to acquisition geometry-dependent estimated models. The multichannel analysis of surface waves in roll-along mode allows construction of ‘pseudo 2D-sections’ by aligning 1D models at each spread midpoint. However, images from field data between forward and reverse can be inconsistent. We apply a generalized inversion to these ‘pseudo 2D-sections’ in the horizontal direction, which removes these inconsistencies and provides an improvement in horizontal resolution, allowing a more objective geological appraisal.
Laterally and Mutually Constrained Inversion of Surface Wave Seismic Data and Resistivity Data
Authors: Wisén Roger , Christiansen Anders V.
Published: November 2006

The laterally and mutually constrained inversion (LCI and MCI) techniques allow for the combined inversion of multiple geophysical datasets and provide a sensitivity analysis of all model parameters. The LCI and MCI work with few-layered models, and are restricted to quasi-layered geological environments. LCI is used successfully for inversion of surface wave (SW) seismic data and MCI for combined inversion of SW data and continuous vertical electrical sounding (CVES) data. The primary model parameters are resistivity or shear wave velocity and thickness, and depth to layer interfaces is included as a secondary model parameter. The advantages and limitations of LCI and MCI are evaluated on synthetic SW data. The main conclusions are: Depth to a high velocity halfspace is generally well-resolved even if thicknesses of overlaying layers and the velocity of the halfspace are unresolved; Applying lateral constraints (LCI) between individual SW soundings improves model resolution, particularly for velocities and depths, and; Adding mutual constraints (MCI) to resistivity data improves model resolution of all parameters in the shear wave velocity model. When applied to field data, model resolution improves significantly when LCI or MCI is used, and resistivity and velocity models correlate structurally with better correlation to lithological interfaces identified in drill logs.
Combined Use of Active and Passive Surface Waves
Authors: Park C. B. , Miller R. D. , Ryden N. , Xia J. , Ivanov J.
Published: November 2006

With a surface wave method to estimate shear-wave velocity (Vs) from dispersion curve(s) of known mode(s), accurate modal identification is obviously a crucial issue. In this regard, the dispersion imaging method is an essential processing tool as it can unfold the multi-modal nature of surface waves through direct wavefield transformations. When a combined dispersion curve of an extended frequency range is prepared from analyses of both passive and active surface waves attempting to increase the maximum depth of Vs estimation, the modal nature of the passive curve (as well as the active one) must be assessed although it has usually been considered the fundamental mode. We report two experimental survey cases performed at the same soil site, but at two different times, employing the passive and active versions of the multichannel analysis of surface waves (MASW) method for an increased investigation depth. In the earlier survey, the modal nature of the imaged dispersion trends from the passive [Formula: see text], and active [Formula: see text] data sets was identified as the fundamental mode, whereas it was confidently re-identified as the first higher mode from the later survey. Modal inspection with the dispersion image created by combining passive and active image data sets was the key to this confident analysis. The modal nature of the passive curve was identified from its context with active curves, whose confident analysis therefore had to come first. An active data set acquired with a small [Formula: see text] receiver spacing and an impact point located close to the receivers appears important for this purpose.
Subsurface Water-filled Fracture Detection by Borehole Radar: A Case History
Authors: Liu Sixin , Sato Motoyuki
Published: November 2006

Operating radar equipment in boreholes offers the possibility of greater depth penetration and higher resolution than is achievable with surface-based ground-penetrating radar systems. We have acquired single-hole radar reflection data in a series of vertical boreholes situated within a granite body west of Beijing, China. Geological logs demonstrate that numerous fractures intersect the boreholes. After processing the single-hole reflection data, linear reflections from many of these fractures are observed. In addition, a large number of linear features that do not intersect the boreholes are interpreted as fracture reflections; they can be traced to distances of [Formula: see text] from the boreholes. Information from single-hole radar reflection data allows the minimum lengths, dips and distances of planar fractures from boreholes to be estimated, but not the azimuths. To determine the azimuths, information from two or more boreholes is required. For our survey site, this was achieved for three of the fractures.
Effects of Clay Content and Salinity on the Spectral Electrical Response of Soils
Authors: Boadu Fred K. , Seabrook Brian C.
Published: November 2006

The spectral electrical responses [Formula: see text] of sand and clay mixtures subjected to an effective stress of [Formula: see text] and saturated with varying concentrations of NaCl are measured in a laboratory environment in the frequency range [Formula: see text]. Changes in clay content and fluid concentrations result in characteristic changes in amplitude and phase spectra. The equivalent circuit model due to Dias is used to characterize the spectral electrical behavior of the saturated mixtures. Two circuit elements of Dias model, the electrochemical parameter [Formula: see text], and the dimensionless parameter [Formula: see text], are particularly sensitive to the amount of clay and the concentration of the pore fluid. The electrochemical parameter [Formula: see text] is shown to increase significantly with an increase in clay content when the soil sample is saturated with freshwater. The dimensionless parameter [Formula: see text] on the other hand is directly related to the concentration of the pore fluid solution (NaCl), increasing with an increase in fluid concentration. Effects of electrode polarization on the [Formula: see text] measurements are modeled and minimized by addition of a Warburg diffusion element term to the equivalent circuit model of the sample.
Collection and Analysis of 3D Magnetic Data for UXO Discrimination
Authors: Gamey T. Jeffrey
Published: November 2006

Magnetic and electromagnetic responses are fundamentally three-dimensional phenomena that we visualize in two dimensions for simplicity. In a single 1D profile, measurement noise and interpretational ambiguities can be reduced at any given point by considering the values of neighboring points along the line. Similarly, noise levels and interpretations can be further enhanced by extending the process from 1D to 2D by considering the values of neighboring lines. It is reasonable to expect that a similar improvement can be obtained by extending this concept from 2D to 3D.
Overview of the water policy process in South Africa
Authors: De Coning Christo
Published: November 2006

This research article provides an overview of the policy process followed by the South African Government in developing and implementing the White Paper on a National Water Policy for South Africa between 1994 and 2003. The research is based on a report published by the South African Water Research Commission (WRC), which formed part of a project entitled: Consolidation and Transfer of Knowledge and Experience Gained in the Development and Implementation of Water and Related Policy in South Africa (WRC Project number K5/1295). An attempt was made in the research project to solicit lessons of experience from the last ten years and to suggest findings regarding future options. It was found that valuable experience exists that is relevant not only to present and future policy and strategy initiatives in South Africa but also to policy process development in a regional and global context. The review of the water policy process has included a deliberate attempt to apply a selected policy process model to the South African water policy process in order to attempt a systematic analysis of the process. Specific findings were made regarding policy and strategy processes, institutional capacity and policy research in the water sector. The findings of the study included a confirmation of the technical quality of the policy and identification of several opportunities and priorities in the implementation of water policy.
Interactions between ants and aphidophagous and coccidophagous ladybirds
Authors: Majerus Michael E. N. , Sloggett John J. , Godeau Jean‐François , Hemptinne Jean‐Louis
Published: November 2006

Aphidophagous and coccidophagous coccinellids come into conflict with homopteran‐tending ants for access to food. Antagonistic interactions between coccinellids and ants may be competitive or non‐competitive. Competitive interactions occur when coccinellids attack aphids or coccids that are being tended by ants for honeydew. Non‐competitive interactions include all interactions away from ant‐tended homopteran colonies. We here review observations and studies of such interactions. We note that most competitive interactions occur at times when untended aphids/coccids are scarce. We describe the chemical and physical defences that coccinellids use against ant aggression and consider whether these have evolved as general anti‐predator deterrents or specifically in response to ants. Myrmecophilous coccinellids are then considered, with particular focus on the two most studied species, Coccinella magnifica and Platynaspis luteorubra. We note that the myrmecophily of the two species has the same adaptive rationale—to enable the ladybirds to prey on ant‐tended aphids at times of aphid scarcity—but that it is based on different traits to facilitate life with ants. Finally, we consider the role of ants in the evolution of habitat specialisation in some coccinellids.
Evolution of the Colored Eco‐Genetic Relationship Map (CEGRM) for Assessing Social Functioning in Women in Hereditary Breast‐Ovarian (HBOC) Families
Authors: Peters June A. , Hoskins Lindsey , Prindiville Sheila , Kenen Regina , Greene Mark H.
Published: November 2006

The CEGRM was initially conceived as a simple, concise, visual representation of the social interaction domains of information, tangible services and emotional exchanges (Kenen, R., & Peters, J. (2001).J Genet Counsel,10, 289–309). A blend of the genetic pedigree, genogram, and ecomap, the CEGRM was developed to facilitate contemporary genetic counseling goals. An exploratory pilot study of 20 subjects showed that it was feasible, comfortable and efficiently accomplished, and that the process was useful both for assessment and as an intervention with study participants (Peters, J. A., Kenen, R., Giusti, R., Loud, J., Weissman, N., & Greene, M. H. (2004).Am J Med Genet Part A,130A, 258–264). Subsequently, we have extended the CEGRM to 150 women from hereditary breast/ovarian cancer (HBOC) families; three different investigators have successfully administered this tool. The preliminary findings from the exploratory study were confirmed in the larger sample. Engaging in the interactive, insight‐promoting CEGRM process provides a novel tool for assessing the social context of genetic testing, and helping high‐risk women better understand and integrate genetic information into their personal and family identities, health beliefs, and decisions.
O‐etherification between glycerol and glycerol monooleate—demonstration of formation of diglycerol monooleate and triglycerol monooleate by fast atom bombardment‐mass spectroscopy and 13C nuclear magnetic resonance
Authors: Eychenne Valérie , Debrauwer Laurent , Mouloungui Zéphirin
Published: November 2006

To prepare glycerol monooleate, we reacted glycerol with oleic acid in the presence of a K1411 sulfonic acid resin in the H+ form. We utilized glycerol monooleate as an emulsifying agent, as it is a nonionic surfactant that is compatible with the initially biphasic reaction medium. If the expected product does not form, small amounts of a highly polar compound are produced. Both diglycerol monooleate and triglycerol monooleate were isolated by preparative chromatography on a silica column (hexane/chloroform/acetone, 25∶50∶50), and were formally identified by fast atom bombardment (FAB)‐mass spectroscopy in positive mode. The products were polyglycerol monoesters. The nature of the products was confirmed by the use of different FAB matrices with or without cationization by alkali metals. The structure of the product was then confirmed by 13C nuclear magnetic resonance. we can now propose a new method of polyglycerol ester preparation that yields interesting nonionic emulsifying agents.
Alcohol‐free diphenyl oxide disulfonate middle‐phase microemulsion systems
Authors: Wu Bin , Harwell Jeffrey H. , Sabatini David A. , Bailey Jason D.
Published: November 2006

Diphenyl oxide disulfonate (DPDS) surfactants were successfully used to formulate Winsor Type III middlephase microemulsion systems with tetrachloroethylene (PCE) and decane. To our knowledge this is the first time that monochain DPDS surfactant phenyloxide monohexadecyl disulfonate surfactant (C16MADS) and commercially available DOWFAX 8390 were found to form middle‐phase microemulsion systems with oils. Hydrophobic dioctyl sodium sulfosuccinate (Aerosol OT) was also used as a cosurfactant to lower the systems' hydropholic‐liphophilic balance. Two organic acids (hydrophobic octanoic acid and hydrophilic l‐tartaric acid) were used in place of the alcohol to formulate middle‐phase microemulsion. The middle‐phase microemulsion systems dramatically increased organic solubility when compared to micellar DPDS surfactant systems. Winsor Type I systems near the Type I–III boundary produced “super” solubilization for hydrophobic oils. Findings from this study enable us to improve DPDS solubilization enhancement of hydrophobic compounds.
Synthesis, characterization and surface properties of 1‐N‐l‐tryptophan‐glycerol‐ether surfactants
Authors: Pegiadou S. , Perez L. , Infante M. R.
Published: November 2006

A novel homologous series of 1‐N‐l‐tryptophanglycerol‐ether surfactants was synthesized and characterized. The precursor compounds, 3‐alkyloxy‐1‐chloropropan‐2‐ols, were prepared from epichlorohydrin and aliphatic alcohols with alkyl chain lengths of 9–16 carbon atoms. Tryptophan was then attached to the monosubstituted glycerol backbone from its α‐amino group through an α‐NH‐C bond. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentrations of the new surfactants, as well as the negative logs of the surfactant concentrations required to reduce the surface tension of the solvent by 20 mN/m (pC20) and the interfacial areas occupied by the surfactant molecules, were calculated from aqueous surface tension measurements using the Wilhelmy plate technique.
Analysis of surfactants: Part I
Authors: Morelli John J. , Szajer Gerald
Published: November 2006

We present a comprehensive review of the literature devoted to the analysis of surfactants. The period covered is 1995 through 1998. We address patents, reviews, books, journal articles, and any conference proceedings abstracted by Chemical Abstract Services. We consider classical, instrumental, and state‐of‐the‐art analytical applications, including those not in common practice but in a developmental stage. We also include analytical techniques that make use of surfactants for improved performance, although such treatment is not comprehensive. Literature from foreign language sources is covered as completely as practical.
Surfactant‐polymer interactions: Mixed micelles of hexadecylpyridinium bromide and trimethyltetradecylammonium bromide in aqueous poly(vinylpyrrolidone) solution
Authors: Bakshi Mandeep Singh
Published: November 2006

The conductance of hexadecylpyridinium bromide (HPyBr) and trimethyltetradecylammonium bromide (TTAB) mixtures over the entire mole fraction range of HPyBr (αHPyBr) was measured in aqueous poly(vinylpyrrolidone) (PVP) solution containing 1, 5, and 10 wt% PVP at 30°C. Each conductivity curve showed two breaks corresponding to two aggregations throughout the whole mole fraction range of HPyBr and TTAB mixtures except for pure TTAB for which a single break corresponding to the conventional critical micelle concentration was observed. The two aggregation processes in the presence of low amounts of PVP were mostly similar to those in pure water, however, 10 wt% PVP shifted the break, corresponding to the second aggregation, toward the higher value. This was attributed to HPyBr/PVP interactions, which were also evident from the appearance of a second break in the conductivity (κ) plot of pure HPyBr in aqueous 10 wt% PVP. From conductivity data, various micellar parameters in the presence of PVP were determined and discussed from the standpoint of micelle‐polymer interactions. The mixing behavior of HPyBr and TTAB corresponding to the first break in the presence of PVP was ideal for the most part and identical to that in pure water.
Direct ethoxylation of a longer‐chain aliphatic ester
Authors: Hreczuch W. , Trathnigg B. , Dziwiński E. , Pyzalski K.
Published: November 2006

2‐Ethylhexyl laurate, as an exemplary longer‐chain aliphatic ester, was subjected to direct ethoxylation. The synthesis was described and the obtained products were analyzed qualitatively by means of the mass spectrometry and chromatographic methods. Solubility of the obtained ethoxylates was studied by determination of their cloud points in selected model solutions. It was shown that longer‐chain aliphatic esters are feasible as raw materials for ethoxylation in the presence of an appropriate catalyst. They undergo effective and selective reaction with ethylene oxide without formation of excessive amounts of by‐products. The obtained products exhibit typical properties of ethoxylate‐type nonionic surfactants. Their solubility in water and butyldiglycol solution was relatively lower compared to their methyl ester equivalents.
Kinetics and thermodynamics of sulfuric acid‐mediated cleavage of substituted diaryl sulfones
Authors: Ward Robert S. , Diaper Richard L. , Roberts David W.
Published: November 2006

The cleavage of di‐p‐tolyl sulfone with concentrated sulfuric acid has been shown to occur at elevated temperatures (>120°C). The products were confirmed as the corresponding sulfonic acids by gas chromatography‐mass spectrometry analysis of the sulfonate ester derivatives. The cleavage reactions of a series of di‐p‐substituted diaryl sulfones with sulfuric acid have been studied. A method using a double end‐point titration has been used to quantify the amounts of sulfonic acid formed as the reactions proceed. These data have been used to construct second‐order rate plots over a range of temperatures and to determine rate constants for the cleavage reactions. The second‐order rate plots showed good linearity. Activation energies were determined from Arrhenius plots of the second‐order rate constants over a range of temperatures. The presence of electron‐donating groups decreases the activation energy of the reaction, whereas the presence of electron‐with‐drawing groups increases the activation energy of the reaction.
Synthesis and surface properties of N‐dodecyl‐N,N‐bis[3‐(aldonamido)propyl]amine‐N‐oxides
Authors: Piasecki Andrzej , Karczewski Sławomir , Syper Ludwik
Published: November 2006

A new group of saccharide surfactants, N‐dodecyl‐N,N‐bis[3‐(aldonamido)propyl]amine‐N‐oxides (derivatives of d‐gluconic, d‐glucoheptonic, and lactobionic acids), were synthesized with high yields by one‐step oxidation reaction of an appropriate N‐dodecyl‐N,N‐bis[3‐(aldonamido)‐propyl]amine with an excess of 30 wt% of an aqueous solution of hydrogen peroxide. Their structures and purity were confirmed by means of elemental analysis, electrospray ionization mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy. In comparison to an appropriate N‐dodecyl‐N,N‐bis[3‐(aldonamido)propyl]amine, the investigated N‐oxides are more soluble in water with similar critical micelle concentration values and show higher surface effectiveness. They are low‐foamable but in mixtures with sodium dodecyl sulfate form high‐volume and stable foams in a wide range of mixture compositions.
Adsorption properties of amphiphilic polyoxyalkylenated dimethylpolysiloxane derivatives on keratin
Authors: Asakura Kouichi , Iida Ayuko , Kitagata Ryoichi , Yoshida Atsushi , Osanai Shuichi , Kuroda Akihiro
Published: November 2006

Adsorption properties of two types of dimethylpolysiloxane backbone derivatives, perfluoroalkyl polyoxyethylenated dimethylpolysiloxane (FPD) and polyoxyethylenated dimethylpolysiloxane (PD), onto keratin surfaces were investigated. Both polymers are amphiphilic, since they possess hydrophilic polyoxyethylene groups. FPD contains a perfluoroalkyl group that provides both water‐and oil‐repellent properties, whereas PD lacks these groups. Adsorption properties of these polymers onto keratin surfaces are considered a good index to evaluate these compounds as nonionics used in hair‐coating agents, since keratin is a major component of hair. FPD was more likely to be adsorbed and less likely to be eliminated from the keratin surface than PD. Once FPD had been adsorbed onto the keratin surface, it was very slowly washed from the surface when it was immersed in stationary water, whereas PD polymers were quickly washed from the keratin surface. Even in running water, rapid elimination of FPD was not observed. The strong resistance to loss of FPD after washing with a large quantity of water may be due to the water‐repellent nature of the perfluoroalkyl groups. As a comparison, FPD adsorption onto a glass surface was also investigated. The affinity to the glass surface was found to be less than to the keratin surface.
31P nuclear magnetic resonance studies on alkyl phosphate emulsifiers in cosmetic oil‐in‐water emulsions
Authors: Plass J. , Emeis D. , Blümich B.
Published: November 2006

Cosmetic oil‐in‐water emulsions with a stearyl phosphate emulsifier are examined by means of static and dynamic 31P nuclear magnetic resonance (NMR) techniques to characterize the molecular properties of the emulsifier in situ. The interfacially bound emulsifier can be deteced by high‐resolution NMR spectroscopy, whereas the excess emulsifier exists as a solid lipid phase not detectable by this technique. The emulsions and the emulsifier raw material, consisting of monostearyl phosphate as well as distearly phosphate, are examined by solid state cross polarization magic angle spinning NMR spectroscopy to prove the existence of solid emulsifier phases in the emulsions. By applying dynamic 31P NMR methods to the interfacially bound emulsifier, information about the molecular dynamics at the interface is obtained. The results of the T1 and T2 relaxation time measurements indicate a restricted motion of the molecules that is dependent on the oil droplet size in the emulsions. This is verified by 31P NMR pulsed gradient spin echo self‐diffusion measurements on emulsions with different droplet sizes. Only about 5 wt% of the total emulsifier used is bound at the interface; the excess forms solid lipid phases. The coverage of the interface seems to be independent of the emulsifier concentration. Only the monoester of the emulsifier raw material shows interfacial activity. Its mobility indicates the two‐dimensional environment of the molecules on the surface of the oil droplets.
The effect of shear and oil/water ratio on the required hydrophile‐lipophile balance for emulsification
Authors: Vander Kloet Jana , Schramm Laurier L.
Published: November 2006

Required hydrophile‐lipophile balance (HLB) values were examined in terms of the nature of kerosene‐water, both oil‐in‐water (O/W) and water‐in‐oil (W/O), emulsions formed using Span 80/Tween 80 surfactant blends. Both the nature of the emulsification method and the oil/water ratio were critical in determining the resulting emulsion type. Both high‐ and low‐shear conditions were investigated. Under high shear, low internal phase emulsions formed using the surfactant mixtures that corresponded to the required HLB values for emulsification involving kerosene (6 for W/O and 14 for O/W). However, at low shear, high internal phase (concentrated) emulsions resulted. Furthermore, depending on the oil/water ratio, some of the high internal phase emulsions were opposite to the type expected, given the HLB of the surfactant blend used. From these results, it appears that the emulsification technique (applied shear and oil/water ratio) used can be of greater importance in determining the final emulsion type than the HLB values of the surfactants themselves.
Novel general procedure for the preparation of homogeneous nonionic surfactants
Authors: Sallay Péter , Farkas László , Szlovák Zoltán , Rusznák István , Bakó Péter , Ahmed Mohamed , Tungler Antal , Fogassy Gabriella
Published: November 2006

Homogeneous nonionic surfactants were produced by the ethoxylation of a selected unit of a homolog series. These particular products are of use for the analysis of nonionics and for the determination of surface characteristics. A new general method for the synthesis of homogeneous nonionic surfactants is described. Ethylene glycol monobenzyl ether was repeatedly reacted in Williamson synthesis (or esterified with acid chlorides in the first step), followed by hydrogenolysis with alkyl‐ or aralkyl alcohols, phenols, carboxylic acids, and amines. Homogeneous nonionics can be synthesized by this method, whereas the conventionally produced ones are usually inhomogeneous.
Displacement of poly(ethylene oxide) adsorbed on silica by a nonionic surfactant studied by spin labeling
Authors: Hommel H. , Van Damme H.
Published: November 2006

Poly(ethylene oxide) chains labeled at one end by a nitroxide free radical were adsorbed on silica. The electron paramagnetic resonance spectrum is mainly sensitive to the local Brownian motion and shows lines typical of two different environments, namely, loops and tails protruding in solution with a fast motion, and trains adsorbed on the solid with a hindered motion. When a solution of nonionic Triton surfactant with different concentrations is put in contact with the coated surface, the polymer segments are progressively removed from the surface and the chains extend into solution. This displacement is recorded as a function of temperature and concentration and follows a well‐defined smooth path.
Disintegration of granules made from pure nonionic surfactants and surfactant mixtures
Authors: Bai Jinhua , Miller Clarence A. , Wilson John E.
Published: November 2006

Dissolution in water of pure liquid nonionic surfactants and some of their mixtures was studied in previous research in this laboratory. In the work described here, a hanging drop slide was used to study disintegration behavior in water of corresponding granules consisting of many zeolite particles bound together with a liquid nonionic surfactant. Granules disintegrated below the cloud point of the nonionic surfactant or mixture. Few differences in disintegration time were seen for various systems. However, disintegration did not occur when the neat surfactant developed viscous myelinic figures upon contact with water. Nor was it observed when a dilute aqueous phase coexisted with a surfactant‐rich L1 phase or L3 (sponge) phase at equilibrium.
Synthesis and characterization of surfactants via epoxidation of tall oil fatty acid
Authors: Hedman Björn , Piispanen Peter , Alami El‐Ouafi , Norin Torbjörn
Published: November 2006

The synthesis and characterization of novel surfactants derived from tall oil fatty acid methyl esters are presented. The tall oil fatty acid methyl esters, which mainly contain methyl oleate, were converted to 9,10‐epoxy derivatives and further transformed to the 9 (or 10) polyethylene glycol (PEG) ethers. Compounds with three different monomethylated PEG chain lengths with molecular weights of 350, 550, and 750, corresponding roughly to 7, 11, and 16 ethylene oxide units, were prepared. Surfactants were formed at an 89% overall yield from tall oil fatty acid. Cloud points were 46, 63, and 84°C, respectively, and surface tensions at the CMC (2.0, 1.0, and 0.4 mM, respectively) varied from 33 to 38 mN/m. Equilibrium surface tension and reflectometry measurements were made and results were similar to those of conventional long alkyl chain PEG surfactants. Results of the tensiometry and reflectometry measurements showed that the surfactants aligned better at the air‐water interface than conventional surfactants. The adsorption properties for the three surfactants were similar to those of polyoxyethylene glycol alkyl ethers.
Synthesis of long‐chain alkanesulfonates by photosulfochlorination using sulfuryl chloride
Authors: Azira Hakima , Assassi Naziha , Tazerouti Amel
Published: November 2006

To develop a new method for the manufacture of anionic surfactants such as alkanesulfonates, which are completely biodegradable, we used linear aliphatic hydrocarbons C12 and C14 as raw material. These hydrocarbons were transformed into the corresponding sulfochlorides in quantitative vield by photosulfochlorination with sulfuryl chloride. The operating conditions led to reaction mixtures containing all the position isomers of sulfochlorinated and chlorinated alkanes. These compounds have been identified by gas chromatography‐mass spectrometry. The isomeric distribution of different reaction products, as well as the molar ratio of the main product, the alkanesulfochlorides, vs. the by‐products, the alkanechlorides, were determined by the gas chromatogrpahy method. The particular isomeric distribution observed during these reactions was different from that of classic chain reactions, as highlighted by the values of calculated relative reactivities. After separation, purification, and alkaline hydrolysis steps, the resulting dodecane and tetradecanesulfonates showed good surface activity. Indeed, the values of the surface tensions at the critical micelle concentration (CMC) compare well with those in the literature. CMC values of these mixtures are given, and the influence of isomeric distribution on CMC values and on the surface tension values at the CMC is presented.
Contact angle of surfactant solutions on precipitated surfactant surfaces. II. Effects of surfactant structure, presence of a subsaturated surfactant, pH, and counterion/surfactant ratio
Authors: Balasuwatthi Piyada , Dechabumphen Nimit , Saiwan Chintana , Scamehorn John F.
Published: November 2006

The contact angle of a saturated aqueous surfactant solution on the precipitate of that surfactant was measured by using the sessile drop method. The sodium and calcium salts of alkyl sulfates (C12, C14, and C18) had advancing contact angles higher than those of alkyl trimethylammonium bromides (C14, C16, and C18). The measured advancing contact angles for several surfactant solutions did not substantially change with varying surfactant/counterion ratios; therefore, the precipitating counterion concentration (e.g., water hardness) had little effect on the wettability. The contact angles of fatty acid (C12 and C16) solutions did not show any dependence on pH between a pH of 4 and 10. The contact angles of saturated calcium dodecanoate (CaC12) solutions containing a second subsaturated surfactant (sodium dodecyl sulfate: NaDS) decreased with increasing NaDS concentrations until reaching the critical micelle concentration of the surfactant mixture. These results show that the second suractant can act as a wetting agent in this saturated surfactant system. Application of Young's equation to contact angles showed that the solid/liquid surface tension can change substantially with surfactant concentration and be important in addition to the liquid/vapor surface tension in reducing contact angles. Application of the Zisman equation results in a “critical” surface tension for the CaC12 or soap scum of 25.5 mN/m, which is comparable to difluoroethene.
Effect of palm kernel oil extraction method on the electrical conductance of Nigerian traditional soaps in alcohols
Authors: Adebajo Moses O. , Akanni Michael S. , Frost Ray L.
Published: November 2006

Nigerian traditional soaps were prepared using two commercial samples of palm kernel oil (black and pale‐orange oils) that were extracted locally using two different traditional methods. The effect of the oil extraction method on the conductance of soaps in alcohols was then investigated. The conductance of the soaps prepared from the pale‐orange oil was higher than that prepared from the black type. The plots of concentration conductance vs. the square root of concentration for methanolic solutions of the pale‐orange oil soaps were linear, whereas the plots obtained for the black oil soaps were nonlinear. The plots of log10k vs. 1/T were linear for all the soaps in methanol and for potassium soaps in 1‐propanol, whereas they were nonlinear for sodium soaps in 1‐propanol. The activation energy terms for the soaps prepared from pale‐orange oil generally decreased with an increase in concentration, whereas the activation energies for the black oil soaps were less sensitive to changes in concentration. These observations suggest that the purity of the palm kernel oil can have a significant effect on the properties and quality of the traditional soaps and that the pale‐orange oil was probably purer than the black type.