bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of the transition from vimentin to neurofilaments during neuronal differentiation
Authors: Yabe Jason T. , Chan Walter K.‐H. , Wang Feng‐Song , Pimenta Aurea , Ortiz Daniela D. , Shea Thomas B.
Published: October 2003

Vimentin (Vm) is initially expressed by nearly all neuronal precursors in vivo, and is replaced by neurofilaments (NFs) shortly after the immature neurons become post‐mitotic. Both Vm and NFs can be transiently detected within the same neurite, and Vm is essential for neuritogenesis at least in culture. How neurons effect the orderly transition from expression of Vm as their predominant intermediate filament to NFs remains unclear. We examined this phenomenon within growing axonal neurites of NB2a/d1 cells. Transfection of cells with a construct expressing Vm conjugated to green fluorescent protein confirmed that axonal transport machinery for Vm persisted following the developmental decrease in Vm, but that the amount undergoing transport decreased in parallel to the observed developmental increase in NF transport. Immunoprecipitation from pulse‐chase radiolabeled cells demonstrated transient co‐precipitation of newly synthesized NF‐H with Vm, followed by increasing co‐precipitation with NF‐L. Immunofluorescent and immuno‐electron microscopic analyses demonstrated that some NF and Vm subunits were incorporated into the same filamentous profiles, but that Vm was excluded from the longitudinally‐oriented “bundle” of closely‐apposed NFs that accumulates within developing axons and is known to undergo slower turnover than individual NFs. These data collectively suggest that developing neurons are able to replace their Vm‐rich cytoskeleton with one rich in NFs simply by down‐regulation of Vm expression and upregulation of NFs, coupled with turnover of existing Vm filaments and Vm‐NF heteropolymers. Cell Motil. Cytoskeleton 56:193–205, 2003. © 2003 Wiley‐Liss, Inc.
3‐D surface charges modulate protrusive and contractile contacts of chondrosarcoma cells
Authors: Vautier Dominique , Hemmerlé Joseph , Vodouhe Constant , Koenig Géraldine , Richert Ludovic , Picart Catherine , Voegel Jean‐Claude , Debry Christian , Chluba Johanna , Ogier Joëlle
Published: October 2003

Up to now, most of the studies addressing the critical roles played by protrusive and contractile cell‐matrix contacts in cell adhesion, guidance, migration, matrix assembly, and activation of signaling molecules have been performed on two‐dimensional surfaces. Here, we analysed the organization of chondrosarcoma cell contacts in a new three‐dimensional environment made of titanium beads. Surface charges were modified by deposition of polyelectrolyte multilayer films built up by alternated polycations poly‐(L‐lysine) or poly(allylamine hydrochloride) and polyanions poly‐(L‐glutamic acid) or poly(sodium 4‐styrenesulfonate). Negatively charged 3‐D titanium surfaces amplified the occurrence and length of cell protrusions. These protrusions had pseudopod characteristics extended to 200 μm in length, growing off the substratum to distant beads. Pseudopod formation is inhibited by the exocytosis inhibitor concanamycin A and is triggered by a secreted factor. Chondrosarcoma cells adhering on uncoated or on negatively charged surfaces contained discrete focal spots of vinculin and actin cables. In cells plated onto these surfaces, phosphorylation of p44/42 MAPK/ERK was twofold increased. In contrast, no cytoskeletal vinculin and actin organization was observed when the surface was positively charged. These data suggest that chondrosarcoma cells adapt a more stable adhesion on uncoated or negatively charged surfaces. This point may be critical in tissue engineering strategies designed for cartilage repair. Cell Motil. Cytoskeleton 56:147–158, 2003. © 2003 Wiley‐Liss, Inc.
A top down description of S‐CIELAB and CIEDE2000
Authors: Johnson Garrett M. , Fairchild Mark D.
Published: October 2003

Recent work in color difference has led to the recommendation of CIEDE2000 for use as an industrial color difference equation. While CIEDE2000 was designed for predicting the visual difference for large isolated patches, it is often desired to determine the perceived difference of color images. The CIE TC8‐02 has been formed to examine these differences. This paper presents an overview of spatial filtering combined with CIEDE2000, to assist TC8‐02 in the evaluation and implementation of an image color difference metric. Based on the S‐CIELAB spatial extension, the objective is to provide a single reference for researchers desiring to utilize this technique. A general overview of how S‐CIELAB functions, as well as a comparison between spatial domain and frequency domain filtering is provided. A reference comparison between three CIE recommended color difference formulae is also provided. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 425–435, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10195
Fabrication of brightness optimizer for CRT color monitors
Authors: Hong‐suk Kim , Seung‐ok Park , Sung‐hyun Kim
Published: October 2003

In CRT monitor characterization accuracy is largely affected by the brightness setting on the monitor. At the optimum brightness level, which adjusts the offsets of RGB channels to nearly zero, CRT monitors have a simple relationship between DAC count and luminance so characterization can be achieved accurately. However, since the optimum brightness levels of CRT monitors are different from one another monitor users, have to make adjustments to the monitor themselves. In this study, a simple device named, brightness optimizer, is fabricated to determine the optimum brightness level objectively. This method uses change of curvature in tone reproduction curves plotted in log‐log scale, according to the changes of brightness level. In this article, the configuration of the brightness optimizer and the measurement processes are described. The repeatability and the accuracy in the measurement of the optimum brightness level for three different CRT monitors are also evaluated. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 468–472, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10199
Sustainable operations through EMS and teamwork: DOD operations and Textron Systems Corporation
Authors: Tingle Joanne , Heislein David
Published: October 2003

The Department of Defense (DOD) is facing the challenge of maintaining troop readiness and sustainable operations while reducing potential
environmental impacts and operational costs. This is occurring while public encroachment around the installations and regulatory restrictions grows,
further restricting DOD's ability to operate and train. DOD is looking to incorporate environmental accountability into day‐to‐day
and future activities at their installations while maintaining a focus on the installations' core missions.

The President issued Executive Order (EO) 13148 in April 2000 to address these challenges through the development and implementation of
Environmental Management Systems (EMSs). The partnering of base personnel, suppliers, and test/training personnel to develop and grow an
EMS can overcome these challenges while maintaining a focus on the overall mission of the military and the development of new munitions. This paper
focuses on the support role of Textron Systems Corporation (TSC), a munitions supplier to DOD, and lessons learned from the application of
EMS at our plants and DOD test ranges. This paper also explores common challenges among TSC and DOD, and our effective solutions to the challenges.
© 2003 Wiley Periodicals, Inc.
New Spill Prevention, Control, and Countermeasure (SPCC) Plan regulations
Authors: Rasmussen Stanley L.
Published: October 2003

The Spill Prevention, Control, and Countermeasure (SPCC) program regulates oil storage vessels at federal and industrial installations
throughout the United States. After proposing revisions in 1991, 1993, and 1997, the EPA finally promulgated, on July 17, 2002, new regulations for the
SPCC program. As written, the new regulations may impose substantial new expense and implementation requirements upon installations. This article
provides a detailed review of the primary requirements of the SPCC program and identifies which issues federal installations may need to address as they
work to meet the August 17, 2004, deadline to review their plan and complete necessary amendments, and the February 18, 2005, deadline to implement those
amendments. © 2003 Wiley Periodicals, Inc.
Cost‐effective strategy for installation and operation of a bioventing system to remediate jet fuel contamination beneath the former refueling apron at Griffiss Air Force Base, New York
Authors: Broschart Michael B. , Lanier John H. , Petkovsek Richard
Published: October 2003

A bioventing system was designed and installed beneath the former refueling apron, Apron 1, to enhance biodegradation of residual jet
fuel‐contaminated soils at the former Griffiss Air Force Base (GAFB) located in Rome, New York. The innovative reuse of existing fuel
supply lines for air injection has allowed for the continued use of the 29‐acre apron surface, while at the same time providing for aeration and
remediation of approximately 60,000 cubic yards of petroleum‐contaminated soil beneath the apron. Additionally, use of the fuel supply lines
eliminated the need for costly saw cutting and excavation of the 18‐inch concrete apron surface, or use of horizontal drilling techniques for
installation of piping to the air injection wells, and resulted in a savings of approximately $150,000. Installation costs were further reduced by
installing aboveground piping to air injection wells located at the former lateral control points in areas isolated from the biopile operations and
maintenance activities. Total remediation costs for contaminated soil beneath the apron are approximately $10 per cubic yard of treated soil.

The former refueling apron is currently used for the ex situ biopile treatment of contaminated soils collected from throughout the
base. The arrangement of the existing biopiles, and the need for additional biopiles on the apron in the future, necessitated the use of underground
piping to supply air to injection wells located at former refueling hydrants. In order to facilitate uninterrupted remediation of the biopiles, existing
underground fuel supply pipelines that were cleaned and closed in place during the deactivation of the refueling apron in 1996 were utilized to supply
air from the edge of the refueling apron to the air injection wells.

This remediation strategy, which maximizes the use of available space by utilizing both in situ and ex situ
treatment technologies, will significantly reduce the period of time required for remediation of contaminated soil at the former GAFB and provides a
cost‐effective approach to attaining beneficial reuse of the site. © 2003 Wiley Periodicals, Inc.
Removal of oils and organic compounds from water and air with MYCELX HRM (Hydrocarbon Removal Matrix) technology
Authors: Alper Hal
Published: October 2003

This article describes the properties and uses of MYCELX HRM (Hydrocarbon Removal Matrix) filters in primary, secondary, and final
treatment of oils and other organic pollutants. MYCELX HRM filters physiochemically capture and immobilize oils and organic compounds rapidly with
negligible delta P and minimal contact time (typically less than one second). Case studies are reviewed in applications including: marine
oily wastewater, PCB remediation, protection of downstream membrane filtration devices, stormwater, boiler condensate, compressor condensate,
removal of oily mists from air, and regeneration of coolant/lubricant. © 2003 Wiley Periodicals, Inc.
Establishing a pragmatic framework for sustainability through pollution prevention
Authors: Ford Jerad A.
Published: October 2003

In the years leading up to the twenty‐first century, we, as a civilization, have made tremendous technological advances and entered the
globalization era. Globalization has brought us to unforeseen levels of productivity, with the United States achieving superpower status. At the same
time, we have witnessed environmental consequences such as global warming, Superfund cleanups, and an increased environmental burden on our air,
water, and land resources. In response, the United States has been regulating environmental activities for approximately three decades with a focus on
creating methods to remediate and restore environmental conditions and preventing current and future environmental degradation. These methods have
been a combination of enforcement through compliance and pollution prevention (P2) through incentives. Scientists and policymakers continue
to struggle with how best to protect the environment while encouraging economic growth.

On our trek to reduce our environmental footprint we have passed through several phases (e.g., enforcement, best available technology)
and, as a nation, seem to be leaning toward sustainability. Sustainability is one of those concepts that is difficult to define because it is based on
global outcomes and values. As a result, sustainability practitioners have been trying to further define sustainability and develop tools for
practicing sustainability. There has been a plethora of confusing terms (sometimes referred to as “eco‐babble”) as
various companies and government agencies tackle the challenge of defining and implementing sustainability. Many definitions are built on the
principles of sustainability, which are often seen as idealistic and impractical. I believe a pragmatic approach to implementing technological
solutions that includes P2 must be used to achieve any level of sustainability, and must be placed in the context of current political and economic
conditions. The P2 approach will enable us to eliminate the dangerous chemicals and processes that comprise our environmental burden, and launch us on
the pathway to reducing, and hopefully eliminating, our environmental footprint. © 2003 Wiley Periodicals, Inc.
Des Kaisers Wasser‐Werke
Authors: Fahlbusch Henning , Manderscheid Hubertus , Ohlig Christoph
Published: October 2003

Die weitläufige Residenz Kaiser Hadrians beeindruckt noch heute. Wie die Anlage mit Wasser versorgt wurde, ist nicht nur für Archäologen aufschlussreich
Das ganze Ausmaß der Antarktis
Authors: Borch René , Mayer Michael , Lindner Klaus , Depenthal Claudia , Heck Bernhard
Published: October 2003

Ein satellitengestütztes Navigationssystem gibt Geowissenschaftlern millimetergenau Auskunft über Hebungs‐ und Senkungsbewegungen der Antarktis
End‐user access to multiple sources: incorporating knowledge discovery into knowledge management
Authors: Morik Katharina , Hüppe Christian , Unterstein Klaus
Published: October 2003

The End‐User Access to Multiple Sources—Eams system—integrates given information sources into a knowledge management system. It relates the world of documents with the database world using an ontology. The focus of developing the Eams system is on the acquisition and maintenance of knowledge. Hence, in both worlds, machine learning is applied. In the document world, a learning search engine adapts to user behaviour by analysing the click‐through‐data. This eases the personalization of selecting appropriate documents for users and does not require further maintenance. In the database world, knowledge discovery in databases (KDD) bridges the gap between the ﬁne granularity of relational databases and the actual information needs of users. KDD extracts knowledge from data and, therefore, allows the knowledge management system to make good use of already existing company data—without further acquisition or maintenance. A graphical user interface provides users with a uniform access to document collections on the Internet (Intranet) as well as to relational databases. Since the ontology generates the items in the user interface, a change in the ontology automatically changes the user interface without further efforts.

The Eams system has been applied to customer relationship management in the insurance domain. Questions to be answered by the system concern customer acquisition (e.g. direct marketing), customer up‐ and cross‐selling (e.g. which products sell well together), and customer retention (here, which customers are likely to leave the insurance company or ask for a return of a capital life insurance). Documents about other insurance companies and demographic data published on the Internet contribute to the answers, as do the results of data analysis of the company's contracts. Copyright © 2003 John Wiley & Sons, Ltd.
Collection of peripheral progenitor cells in paediatric patients with a new programme for the collection of mononuclear cells
Authors: Moog R. , Basu O. , Kremens B.
Published: October 2003

When harvesting peripheral progenitor cells (PPC) in children, the special situation of their circulatory system has to be taken into account. Therefore, extracorporeal blood volume and product volume should be small to avoid side effects. Nine children (age 2–14 years, weight 12.8–58.5 kg) with malignancies underwent 10 PPC collections with the MNC programme of the Amicus blood cell separator. The disposable kit was primed with red blood cells (RBCs) or human albumin to avoid circulatory side effects. The children were monitored for blood pressure and heart rate during the whole apheresis procedure. A median blood volume of 4,577 ml (range 3,536–8,596 ml) was processed in a separation time of 270 min (range 176–331 min). The median product weight was 81 g (range 53–107 g) and the yield of CD 34 antigen expressing cells was 12.5 × 106/kg body weight (range 1.8–26 × 106/kg body weight). Only one child had to undergo a second apheresis to collect the desired transplantation dose. The median platelet contamination of the product was 0.32 × 1011 (0.13–0.85 × 1011). No circulatory side effects were observed. Blood flow alarms occurred in seven of ten aphereses and one collection had to be terminated due to insufficient flow. PPC can be efficiently collected in children with the MNC programme without circulatory side effects. The platelet contamination of the product was low due to the elutriation principle of the collection process, thereby avoiding thrombocytopenic bleeding episodes in the patients. J. Clin. Apheresis, 18:111–114, 2003. © 2003 Wiley‐Liss, Inc.
LDL‐apheresis up‐regulates VEGF and IGF‐I in patients with ischemic limb
Authors: Kobayashi Shuzo , Moriya Hidekazu , Negishi Kousuke , Maesato Kyouko , Ohtake Takayasu
Published: October 2003

Although it is known that LDL‐apheresis improves ischemic limb seen in patients with peripheral arterial occlusive disease (PAOD), the underlying mechanism(s) still remains unknown. We studied whether vascular endothelial growth factor (VEGF) and/or insulin‐like growth factor‐I (IGF‐I) levels correlated with improvement of ischemic limbs after LDL‐apheresis. Sixteen patients with PAOD (13 men, 3 women) were enrolled in our study. LDL‐apheresis was performed 10 times (treated plasma 3,000 ml) for 5 weeks. Serum level of VEGF significantly increased from 262 ± 171 pg/ml to 306 ± 165 pg/ml before and after LDL‐apheresis (P < 0.05). This value further increased up to 441 ± 175 pg/ml 3 months after the end of this therapy (P < 0.01, compared with the basal value and P < 0.05, compared with the value at the end of 10‐times session). Increased levels of VEGF paralleled increases in the ankle‐brachial pressure index (ABI). After 10‐times therapy, IGF‐I significantly decreased (P < 0.05), but increased over the basal value 3 months after this therapy. Plasma fibrinogen statistically decreased and remained low for 3 months. The favorable effects of LDL‐apheresis may be ascribed to up‐regulation of VEGF and IGF‐I associated with decreased fibrinogen levels. J. Clin. Apheresis, 18:115–119, 2003. © 2003 Wiley‐Liss, Inc.
Plasmapheresis for the treatment of acute pancreatitis induced by hemophagocytic syndrome related to hypertriglyceridemia
Authors: Coman Tereza , Dalloz Marie‐Amélie , Coolen Nathalie , Heshmati Farhad , Pene Frédéric , Cariou Alain , Claessens Yann‐Erick
Published: October 2003

Histiocytic cytophagic panniculitis is an unusual form of hemophagocytic syndrome related to T‐cell lymphoma that can be responsible for hypertriglyceridemia. The elevation of serum triglycerides, usually in the setting of familial lipidemia or during uncontrolled diabetes mellitus, is a well‐recognized cause of pancreatitis. We report here on the treatment by plasmapheresis of a patient suffering from a T‐cell lymphoma‐related panniculitis who presented with an acute pancreatitis induced by hypertriglyceridemia. The Ranson scoring system at day 2 was increased and predicted a poor course while clinical features worsened. The patient was treated with one plasmapheresis that allowed a dramatic (89%) decrease in the triglycerides level. The acute pancreatitis resolved and the patient was discharged from the intensive care unit at day 5 with lipids and pancreatic enzyme levels within normal range. To our knowledge, this is the first case of acute pancreatitis induced by hypertriglyceridemia in the setting of an uncontrolled cytophagic histiocytic panniculitis successfully treated by plasmapheresis. J. Clin. Apheresis 18:129–131, 2003. © 2003 Wiley‐Liss, Inc.
Safety of donating multiple products in a single apheresis collection: Are we expecting too much?
Authors: Strauss Ronald G.
Published: October 2003

Modern blood separators rapidly process many liters of donor blood and efficiently collect vast quantities of blood components from donors, who may be stimulated with potent recombinant hematopoietic growth factors or cytokines. Accordingly, the potential risks of modern multiple product/unit apheresis donations and recombinant growth factors is analyzed in this report. As is true for all medical procedures, risks are associated with apheresis donations. Risks of a “standard” apheresis donation, in which one unit of PLTs or plasma is collected, are comparable to the risks of whole blood donation. Risks of multiple unit apheresis donations, in which either vast quantities of a single blood component or multiple units of various components are collected, are incompletely understood, particularly, when donors are stimulated with recombinant hematopoietic growth factors to increase component yields. To minimize donor risks and to increase knowledge of multiple component apheresis donations, both short‐term problems (e.g., donor reactions accompanying apheresis procedures and pre‐ vs. post‐procedure changes in results of donor laboratory studies) and long‐term problems (e.g., medical diagnoses/problems and abnormalities of donor blood counts and laboratory test results) should be monitored, ideally, by a repeat donor registry. When recombinant hematopoietic growth factors are prescribed, donors should give informed consent, and blood center professionals must be aware of 1) the effects of these drugs given at pharmacologic, rather than physiologic, doses; 2) the differences between the molecular structure of recombinant vs. natural/endogenous growth factors; 3) the fact that recombinant growth factors have both narrow/focused and broad biological activities; and 4) the probability that results of studies in sick/immunosuppressed patients may not be applicable to healthy/immunocompetent donors. J. Clin. Apheresis 18:135–140, 2003. © 2003 Wiley‐Liss, Inc.
Renal transplantation: Basic concepts and evolution of therapy
Authors: Braun William E.
Published: October 2003

Within the last 5 years, dramatic changes in the area of renal transplantation have occurred. There have been shifts in the dominant types of rejection, and in the types and utilization of immunosuppressants. Hyperacute rejection is now rarely seen, and acute cellular rejection within the first 6 to 12 months has been reduced to about 10%. However, humoral/antibody‐mediated rejection has become a more prevalent problem.In the area of immunosuppressants, the ability to reduce acute cellular rejection to about 10% has been achieved through more judicious use of calcineurin inhibitors (cyclosporine and tacrolimus), increased use of mycophenolate mofetil, and the recent introduction of sirolimus (rapamycin). The polyclonal antibody (antithymocyte globulin), as well as monoclonal antibodies directed against the alpha chain of CD25 (daclizumab and basilixamab), have added substantially to the improved success of renal allografts. Because of numerous serious toxicities from glucocorticoids and calcineurin inhibitors, particularly cyclosporine, new studies are utilizing calcineurin‐free and/or glucocorticoid avoidance or rapid elimination protocols often in combination with a monoclonal antibody and sirolimus. New immunosuppressants such as FTY720 and Campath‐1 are also under study. In addition to its use in treating patients with low‐level donor‐specific antibody before transplantation in order to avoid hyperacute rejection, apheresis is utilized in various combination protocols after transplantation in the management of humoral/antibody‐mediated rejection, in the treatment of hemolytic uremia syndrome that sometimes occurs with calcineurin inhibitors and sirolimus, as well as in the treatment of focal segmental glomerulosclerosis that has a major risk of recurrence in renal transplants. J. Clin. Apheresis 18:141–152, 2003. J. Clin. Apheresis 18:141–152, 2003. © 2003 Wiley‐Liss, Inc.
Coal cleaning via liquid‐fluidized bed classification (LFBC) with selective particle modification
Authors: Calo J. M. , Hu Xinhui , Logan Timothy , Choi Debbie , Apicello Jocelyn
Published: October 2003

The concept of coal beneficiation by particle segregation in water‐fluidized beds (or liquid‐fluidized bed classification – LFBC) and its improvement via selective solvent‐swelling of organic material‐rich coal particles were investigated in this study. Samples of Kentucky #9 and Illinois #6 U.S. coals of varying sizes were used in the investigations, both unswollen and swollen with acetone and saturated phenol‐water solution. Both solvents were effective swelling agents for both coals. Leaching of the solvents out of the coal particles into water was also observed to occur. This was found to be more rapid for phenol than for acetone. However, it is concluded that this process is still slow enough to allow sufficient time for segregation and separation of solvent‐swollen coal particles in a water‐fluidized bed. Particle segregation by size was observed for all the unswollen coal samples, with particle sizes increasing from top to bottom in the LFBC. Since the organic matter in the coal tends to concentrate in the smaller particles, the larger particles are typically denser. Consequently, LFBC naturally tends to separate coal particles according to mineral matter content, both due to density and size. For samples of the “larger” coal particles, it was found that solvent‐swelling did not have a significant effect on improving beneficiation over that obtained for the corresponding unswollen coal particles. This was attributed to “larger” coal particles being more similar in organic/inorganic composition. For the “smaller” coal particle samples, however, a significant improvement in beneficiation was observed due to solvent‐swelling. The ratio of bottoms/overflow particle ash content obtained was in the range of 2–4. The size range of these “smaller” particles is quite similar to that typically used in pulverized coal combustion.
Matching average masses of pitch fractions of narrow polydispersity, derived from matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry, with the polystyrene calibration of SEC
Authors: Islas Carlos A. , Suelves Isabel , Millan Marcos , Apicella Barbara , Lazaro Maria‐Jesus , Herod Alan A. , Kandiyoti Rafael
Published: October 2003

A coal tar pitch has been fractionated by preparative and analytical size exclusion chromatography (SEC) to provide narrow time‐elution fractions, expected to have relatively low molecular dispersities. The fractions were characterised by analytical SEC, by UV‐fluorescence spectroscopy, and by laser‐desorption MS and by MALDI‐MS using sinapinic acid as matrix. The MALDI spectra were evaluated by measuring the peak‐intensity mass, Mp, and by calculating number (Mn) and weight (Mw) average masses. The high mass limits of the spectra were determined by three methods based on (i) truncating the spectrum when the signal fell below 5 times the standard deviation of signal at the instrument limit, (ii) taking the upper mass as defined by a minimum slope of the spectrum from baseline, and (iii) taking all of the high mass signal as from sample. The laser desorption spectra were evaluated by Mp values only; the results below m/z 1,000 were in excellent agreement with the polymer calibration. The MALDI mass spectra gave a good fit between Mp values below m/z 3,000 and the calibration of SEC by polymers. Working with Mp gave better results than the Mn and Mw values from Method (i). Results from Methods (ii) and (iii) were significantly worse. Reasons for the lack of agreement between results above m/z 3,000 by MALDI and above m/z 1,000 by LD‐MS have been discussed.
On‐line LC‐GC method for determination of isomers of nervonic acid in meat‐derived food
Authors: Barcarolo Robertino , Bau Andrea , Moreno Josefa Barrero , Dimitrova Burya , Anklam Elke
Published: October 2003

An on‐line liquid chromatography‐gas chromatography (LC‐GC) method for determination of the cis/trans isomers of nervonic acid in meat‐derived food is described. The technique used a home‐assembled LC‐GC coupled system. A simple LC clean‐up procedure using an analytical gel permeation (5 μm) column and 1% ethyl acetate in hexane as mobile phase has proved to be suitable for the isolation and purification of fatty acid methyl esters from the meat matrix. Use of a silica gel (5 μm) pre‐column improved the separation of cis/trans nervonic acid from cholesterol and the more polar constituents of the extracted fraction. GC analyses were performed using a non‐polar GC column and mass spectrometry (MS) for identification of the analytes and flame ionization detector (FID) for quantification of the compounds studied. Excellent linearity with correlation coefficients higher than 0.999 in the range of 0.05–10 μg mL–1 nervonic acid and a good repeatability with relative standard deviation (RSD) values generally lower than 4% was obtained. The method developed provides a high sensitivity for trace analysis of the cis/trans isomers of nervonic acid and enables complete automation.
Open tubular liquid chromatographic separations using an aptamer stationary phase
Authors: Clark Stacey L. , Remcho Vincent T.
Published: October 2003

Aptamers are oligonucleotides which are isolated in vitro based on their affinity for a target molecule. These molecules hold promise for use in analytical methods which rely on molecular recognition. In this study, we report the immobilization of an RNA aptamer on the inner walls of fused silica capillaries. Due to the small size of these molecules, the resulting surface coverage of these capillaries made them suitable for use in open tubular liquid chromatographic studies. These capillaries also exhibited stability when an organic modifier was added to the mobile phase. These characteristics of aptamers make them desirable over traditional affinity chromatography stationary phases.
Multi‐compound methods for the detection of pharmaceutical residues in various waters applying solid phase extraction (SPE) and gas chromatography with mass spectrometric (GC‐MS) detection
Authors: Reddersen Kirsten , Heberer Thomas
Published: October 2003

This paper describes two highly sensitive analytical methods for the unambiguous determination of pharmaceutical residues and related polar contaminants in environmental water samples. Both analytical methods use solid phase extraction (SPE), chemical derivatization, and detection of the analytes by capillary gas chromatography‐mass spectrometry (GC‐MS) with selected ion monitoring (SIM). Using the two methods, a total of 19 pharmaceuticals and 7 related polar contaminants, most of them pesticides, can be detected and quantified down to the low ng/L range in sewage, surface, ground, and drinking water. Recoveries between 70 and 110% and standard deviations of less than 15% were determined for 21 analytes when applying the analytical method that uses pentafluorobenzyl bromide (PFBBr) for derivatization. The second method, which employs N‐(t‐butyldimethylsilyl)‐N‐methyltrifluoroacetamide (MTBSTFA) for derivatization was found to be slightly less sensitive and reproducible but it also permitted the analysis of several other environmentally important compounds such as the antiepileptic drugs carbamazepine or primidone. From spiking experiments, limits of detection (LODs) between less than 1 and 10 ng/L and limits of quantification (LOQs) between 1 and 40 ng/L were calculated.
Polymer‐bound cellulose phenylcarbamate derivatives as chiral stationary phases for enantioselective HPLC
Authors: Ling Frank , Brahmachary Enugurthi , Xu Mingcheng , Svec Frantisek , Fréchet Jean M. J.
Published: October 2003

Novel chiral stationary phases (CSP) have been prepared by coating the internal surface of monodisperse macroporous poly(2‐aminoethyl methacrylate‐co‐ethylene dimethacrylate) beads with dimethylphenylcarbamate derivatives of regenerated cellulose. The coating was achieved either by simple adsorption or by chemical bonding using a diisocyanate linker. Separation of enantiomers in normal‐phase HPLC mode was used to evaluate the enantioselectivity of all CSPs. The influence of the properties of the polymer support such as pore size, pore volume, and content of the amine functionalities, reaction and separation conditions such as weight ratio of modified cellulose selector to polymer beads, amount of diisocyanate crosslinker, and the composition of the mobile phase on chiral discrimination and chromatographic resolution were also systematically investigated. The CSPs prepared by chemical anchoring were more stable and a wider range of solvents including dichloromethane could be used for the separations. Compared to the coated‐type CSPs, the chemically bonded stationary phases enabled the enantioseparations of a larger number of racemates and exhibited enantioselectivity fully comparable to their counterparts prepared using porous silica as a support. However, the benefits of tailored macroporous polymer supports demonstrated earlier with brush‐type CSPs did not enhance the performance of the chiral stationary phases prepared from cellulose‐based selectors.
Analysis of tramadol in pharmaceutical preparations by high performance thin layer chromatography
Authors: Meyyanathan S. N. , Kumar Pradeep , Suresh B.
Published: October 2003

A new simple, precise, rapid, and selective high‐performance thin layer chromatography (HPTLC) method has been developed for the analysis of tramadol in pharmaceutical formulations. The method uses chlorzoxazone as an internal standard. The stationary phase was silica gel 60F254 prewashed with methanol; ethyl acetate‐methanol‐ammonia solution 7 + 1 + 0.5 (v/v) was used as mobile phase. Detection and quantification were performed densitometrically at λ = 275 nm. The linear range of the analysis was 1.0–2.5 μg and the percentage recovery was 104.6%.
Enantiomeric resolution of some human aldosterone synthase [CYP 11 B2] inhibitors on derivatized polysaccharide chiral stationary phases
Authors: Aboul‐Enein Hassan Y. , Hefnawy Mohamed M. , Ehmer Peter B. , Hartmann Rolf W.
Published: October 2003

Aldosterone synthase (CYP 11 B2) is a mitochrondrial cytochrome P450 enzyme catalyzing the last steps of aldosterone production in the adrenal cortex. A new pharmacological approach for the treatment of the aldosterone‐induced effects in congestive heart failure and all forms of hyperaldosteronism could be achieved through the use of (CYP 11 B2) inhibitors. The chiral resolution of some of active compounds, namely 1‐(4‐pyridyl(methyl)tetralin (I)), 7‐chloro‐1‐(1‐imidazolyl)tetralin (II), and 5‐hydroxy‐2‐(4‐pyridylmethyl)indane (III), on various polysaccharide derivative chiral stationary phases, namely Chiralcel OD, OJ, OC, and Chiralpak AD and AS, in normal phase mode was achieved. The mobile phase used was hexane/2‐propanol/triethylamine (9 : 1 : 0.1 v/v/v). The flow rate of the mobile phase was 0.8 mL/min and the wavelengths of detection of compounds I, II, and III were set at 288, 271, and 254 nm, respectively. The chromatographic parameters: retention factor (k), selectivity (α), and resolution factor (Rs) were calculated. The chiral recognition mechanisms between these analytes and chiral selectors are discussed.
A trifluoropropyl‐containing silphenylene–siloxane terpolymer for high temperature gas chromatography
Authors: Mayer Bernhard X. , Rauter Walfried , Kählig Hanspeter , Zöllner Peter
Published: October 2003

A silanol terminated tetramethyl‐p‐silphenylene–3,3,3‐trifluoropropylmethyl, dimethyl siloxane terpolymer was prepared by a condensation reaction. Its chemical composition and microstructure were characterized by 1H and 29Si nuclear magnetic resonance spectroscopy. The polymer was coated on fused silica capillary columns in order to evaluate its gas chromatographic properties. At moderate temperatures its selectivity is similar to that of medium polarity stationary phases; at high temperatures, however, the interactions between stationary phase and unsaturated triacylglycerols are reduced to such an extent that the typical GC behavior of an apolar phase could be observed. Furthermore, the columns showed high separation efficiency and a good inertness of the fused silica surface. Relatively low column bleed permitted a maximum allowable operating temperature of 360°C. These capillary columns were used to determine the distribution of the carbon numbers of triacylglycerols in extracts of human subcutaneous adipose tissue. Thermal treatment of the columns at 400°C leads to a high degree of immobilization associated with reduced column bleed and a slightly changed selectivity, which indicates that a crosslinking process has taken place. Nevertheless, decreased separation efficiency and the thermal instability of the trifluoropropyl group would indicate that the capillary columns should be used at temperatures < 380°C.
Experimental evaluation of possible side effects of intra‐operative photodynamic therapy on rabbit blood vessels and nerves
Authors: Kübler Alexander C. , Stenzel W. , Rühling M. , Meul B. , Fischer J.‐H.
Published: October 2003

Background and Objectives

Tumours of the head and neck show a high local tumour recurrence rate ranging between 7 and 30% despite combined treatment modalities. To improve these data, photodynamic therapy (PDT) might be used as an additional treatment besides surgery and radio‐chemotherapy. Intra‐operative PDT has been proposed to “sterilise” the tumour bed after surgical tumour resection in order to kill any remaining tumour cells which are responsible for local tumour recurrences. Often, during head and neck surgery, large blood vessels and important nerve structures are exposed and could potentially be harmed by intra‐operative PDT. Despite the fact that mTHPC is the most commonly used photosensitiser for head and neck tumours, there are no data on potential detrimental side effects of intra‐operative PDT onto these vital structures. The purpose of this study was to use a maximal treatment protocol in rabbit observing possible damage to the blood vessels and nerve structures and thus judge the most severe event that could happen in patients.

Study Design/Materials and Methods

In rabbits the large blood vessels and nerve structures at the neck and at the groin area were surgically exposed and treated by mTHPC‐mediated intra‐operative PDT. Various treatment parameters (drug‐light interval, light dosage, follow up interval) were modified in order to find the critical treatment parameters which might cause maximum tissue effects. The intention was to define the most severe clinical complications which could be expected from mTHPC mediated intra‐operative PDT.

Results

The most severe tissue reactions were found at a drug dosage of 0.3 mg/kg, a drug‐light interval of 24 hours and a light dosage of 20 J/cm2. Complete necrosis was found for the muscles, fat and connective tissue within the entire treatment field. Blood vessels demonstrated severe oedema, media‐hyperplasia or loosening of the endothelial layer leading to various degrees of local thrombosis but no break down of the vessel wall or any rupture was noted. Most nerves were altered by a 75% demyelisation but this did not result in any clinical symptoms.

Conclusions

Our results have shown that mTHPC mediated intra‐operative PDT used with a maximal treatment protocol (very high doses and very short drug‐light intervals) has significant histological impact onto all tissue structures, but did not show any clinical symptoms in rabbits. mTHPC mediated intra‐operative PDT seems to be a promising and a safe treatment option which could complement existing treatment modalities in order to improve total survival rate of tumour patients. Lasers Surg. Med. 33:247–255, 2003. © 2003 Wiley‐Liss, Inc.
Influence of an optically thick water layer on the bond‐strength of composite resin to dental enamel after IR laser ablation
Authors: Staninec Michal , Xie John , Le Charles Q. , Fried Daniel
Published: October 2003

Background and Objectives

Several studies of hard tissue ablation with Er:YAG lasers have shown that the addition of an optically thick water layer (∼1 mm) added to the surface of dental enamel before each incident laser pulse, profoundly influences the rate and efficiency of ablation and the resulting surface morphology. The objective of this study was the determination of laser parameters which result in clinically useful bond strengths without the need for phosphoric acid etching. The hypothesis to be tested was that laser irradiation through a relatively thick layer of water would result in a surface to which composite could be bonded with bond strength similar to surfaces etched with phosphoric acid. This hypothesis is predicated on the assumption that the water prevents the formation of non‐apatite calcium phosphate phases on the enamel surface.

Materials and Methods

In this study, a calibrated syringe pump and a motion control system were used to uniformly treat flat enamel surfaces using free‐running Er:YAG laser pulses with and without water, and 9.6 μm CO2 laser pulses on a dry surface for comparison. The rate of water delivery that resulted in the most efficient ablation was determined by profiling the resulting laser incisions using optical coherence tomography. In addition, enamel surfaces of 5 × 5 mm2 were uniformly treated and the resulting surface morphology was examined using synchrotron radiation‐fourier transform infrared spectroscopy (SR‐FTIR), and optical and electron microscopy. The influence of the modified surface morphology on the adhesion of composite resin was investigated.

Results

The shear‐bond strength of composite bonded to enamel surfaces irradiated at intensities clinically relevant for caries removal approached values measured for conventional acid etching when the water delivery rate was optimized.

Conclusions

This study demonstrates that composite restorative materials can be directly bonded to laser prepared surfaces without the necessity of further surface preparation and acid etching and that the addition of a thick water layer (∼1 mm) prevents the formation of undesirable CaP phases that compromise adhesion to restorative materials. Lasers Surg. Med. 33:264–269, 2003. © 2003 Wiley‐Liss, Inc.
The role of ring‐ring equilibria in thermodynamically controlled polycondensations
Authors: Kricheldorf Hans R.
Published: October 2003

Thermodynamically controlled polycondensations (TCPs) involve rapid equilibration reactions, such as transesterification, transamidation, etc. An important component of these equilibration reactions is the reversible formation of cyclic oligomers and polymers by “back‐biting”. Therefore, TCPs were described in the previous literature in terms of ring‐chain equilibria. The present study presents a complementary theory saying that ring‐chain equilibria automatically include ring‐ring equilibria which gain in importance with higher conversions because the molar ratio of rings versus linear chains rapidly increases. At 100% conversion, all reaction products will be cycles and the ring‐ring equilibria limit the chain growth. Several polycondensations cited from the literature are discussed in the light of the new theory.
Nonstoichiometric polycondensation I. synthesis of polythioether from dibromomethane and 4,4′‐thiobisbenzenethiol
Authors: Iimori Hirokazu , Shibasaki Yuji , Ando Shinji , Ueda Mitsuru
Published: October 2003

High molecular weight poly(phenylene thioether) (3) was successfully obtained by the polycondensation of 4,4′‐thiobisbenzenethiol (1) and dibromomethane (2) with a variety of feed ratios in the presence of 1,8‐diazabicyclo[5,4,0]undec‐7‐ene (DBU) in 1‐methyl‐2‐pyrrolidinone (NMP) at 75°C. The resulting polymer showed the maximum inherent viscosity (ηinh) of 0.50 dL/g in 4 h when 1.5 equivalents excess of 2 was used. The model reaction using benzenethiol (4) and dichloromethane (5) in the presence of DBU in deuterated dimethylsulfoxide (DMSO‐d6) at 25°C indicated that the rate of the second nucleophilic displacement reaction (k2) is 61 times faster than that of the first one (k1). The maximum of theoretical molecular weights calculated at various stoichiometric imbalance (S) under the condition of k2/k1 = 61 showed a good agreement with the experimental molecular weights at specific polymerization times.
Polyaddition reaction in a dispersed medium: elaboration of new core‐shell polyurethane particles
Authors: Chambon Pierre , Radhakrishnan Bindushree , Cloutet Eric , Papon Eric , Cramail Henri
Published: October 2003

The elaboration in a dispersed organic medium of calibrated polyurethane particles with a core‐shell structure is presented in this paper. The objective could be achieved by using a series of reactive steric stabilizers of the type ω‐(OH)x‐poly(n‐butyl acrylate), ‐polystyrene, ‐polysiloxane or ‐polybutadiene (x=1 or 2) that play the role of surfmers during the polyaddition reaction between ethylene glycol and tolylene‐2,4‐diisocyanate, in cyclohexane as a dispersant medium. The final size of the polyurethane particles (0,5‐10 μm) was found to be a function of the steric stabilizer characteristics (nature, molar mass and concentration) and of the addition procedure of the different reactants. These novel particles constituted of a polyurethane core and various shells depending on the stabilizer used exhibit specific and original properties.
Control of macromolecular architecture of polyamides by poly‐functional agents. 2. Use of oligomerization in polycondensation study
Authors: Yuan Cuiming , Di Silvestro Giuseppe , Speroni Franco , Guaita Cesare , Zhang Haichun
Published: October 2003

In the first paper of the series, a statistical model for star‐branched polycondenzation of AB type monomers in the presence of a polyfunctional agent RAf was completely developed. The analytical expressions obtained for the number‐average (D̄P̄n̄) and weight‐average (D̄P̄w̄) degree of polymerization, and the dispersion index (D) for whole polymer species, linear and star macromolecular chains, are now derived as function of the feed and of end‐group analysis. Also the important molecular parameter, mole fraction of star‐branched polymer, can be evaluated. Some numerical examples are presented. It is illustrated that the molecular weight properties of the linear and star‐branched polymers in the mixture of the products, very important factors for the application of this kind of polymeric materials, can be determined starting from the feed and terminal group analysis.

Polymerization and oligomerization of 6‐aminocaproic acid were carried out in the presence of trimesic (T3) acid and 2,2,6,6‐tetra(β‐carboxyethyl)cyclohexanone (T4) and EDTA as tri‐ and terra‐functional agents. The molecular weights calculated are in good agreement with those obtained by Size Exclusion Chromatography (SEC), end group analysis and NMR spectra.