bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mixers with Microstructured Foils for Chemical Production Purposes
Authors: Werner B. , Hessel V. , Löb P. 
Published: March 2005

AbstractFor about the past ten years the Institut für Mikrotechnik Mainz GmbH (IMM) has been engaged in the application of micro structures for chemical micro process engineering. Their advantages – more efficient heat exchange and mass transport – lead to, among other things, an increase in yield and selectivity even while saving resources. The development of microstructured mixers thereby played a key role for carrying out advanced syntheses of fine chemicals, as well as for the generation of dispersions, creams, foams and emulsions. So far, microstructured mixers have been mainly limited to laboratory‐scale or at best pilot plant‐scale – typical maximum flow rates were from 2–100 L/h for low viscosity systems. With the introduction of the StarLaminators StarLam300 and StarLam3000, this barrier could be lifted far beyond 300 L/h up to the m3/h domain. Both apparatus yield at high flow rates a mixing efficiency which reaches the high performance of today's low‐capacity (L/h) micromixers. Therefore, continuity exists from the “real” micromixers and the high‐throughput tools described below to conventionally manufactured static mixers with even higher flow rates. A classification of the mixing efficiency versus the power input confirms this continuity as well.
Development of Highly Active Pd‐ZnO/Al2O3 Catalysts for Microscale Fuel Processor Applications
Authors: Xia G. , Holladay J. D. , Dagle R A.. , Jones E. O. , Wang Y. 
Published: March 2005

AbstractA series of alumina supported Pd‐ZnO catalysts were synthesized and studied for methanol steam reforming. Pd loading and Pd/Zn ratio were optimized to improve catalyst activities. Among all the catalysts studied, the catalyst with a Pd loading of 8.9 wt % and a Pd/Zn molar ratio of 0.38 exhibited the highest methanol conversion and the lowest CO selectivity. The significantly improved Pd‐ZnO/Al2O3 catalyst activity was one of the main factors improving the efficiency of a microscale fuel processor from 9 % to 15 %.
Concepts for Modularization and Automation of Microreaction Technology
Authors: Löbbecke S. , Ferstl W. , Panić S. , Türcke T. 
Published: March 2005

AbstractTwo different concepts for the modularization and automation of microreaction systems are described. The modular microreaction system FAMOS was developed on the basis of a functional toolkit concept for laboratory applications of microreaction technology. Microstructured reaction modules with suitable fluidic, analytical and electronic interfaces were designed which allow the realization of even multi‐stage microchemical processes like the sulfonation of toluene under thermally controlled conditions over the entire process. The automated microreaction system AuMμRes was developed to enable an active regulation of process parameters via a process control system to perform parameter screenings for the identification of process optima. Integrated microstructured flow‐through sensors and analytical interfaces were developed for the monitoring of relevant process parameters. Sampling devices for chromatographic analysis and inline Raman spectroscopy were integrated into the micoreaction system to gather relevant analytical information about the considered chemical process. By applying chemometric models, a qualitative and quantitative realtime monitoring of microchemical processes was established, as was demonstrated for different nitration reactions.
Application Report on Operating Cellular Process Chemistry Plants in Fine Chemical and Contract Manufacturing Industries
Authors: Schwalbe T. , Kursawe A. , Sommer J. 
Published: March 2005

AbstractOnly a few microreaction manufacturing plants are being operated to date. The performance of two different microreaction manufacturing plants is discussed, one in a dedicated application, the other in a multi‐purpose environment. Strategies to address the major design and operating challenges for microreactor manufacturing plants to equipartition starting material streams into parallel reaction chambers throughout manufacturing operation are provided for demanding liquid/liquid‐reactions. The importance of minimizing the pressure drop variances between different microreactors or channels by rigorous microreactor fabrication process control is described. A cost/performance balanced microreactor manufacturing strategy is suggested, and the ease of assessing trade‐off decisions is addressed for different manufacturing systems by the use of a case study involving a diffusion controlled Grignard reaction.
Analysis of Microstructured Reactor Characteristics for Process Miniaturization and Intensification
Authors: Commenge J.‐M. , Falk L. , Corriou J.‐P. , Matlosz M. 
Published: March 2005

AbstractThe present study investigates a number of key features of microstructured reactors and components devoted to process miniaturization and intensification. For processes involving transfer operations and/or chemical reactions, a simple model can be used to relate the process efficiency to the ratio of two characteristic times: the space time of the process fluid in the system and the characteristic time of the operation. A detailed analysis of the relationship between these characteristic times and the characteristic dimensions of the system highlights the principal operations that should most benefit from the potential of microstructured process components. The analysis is used to examine how microstructured reactors may be advantageously employed to improve process efficiency (intensification) or to reduce process size (miniaturization), as a function of the operations involved.
Production and Characteristics of Microreactors Made from Glass
Authors: Dietrich T. R. , Freitag A. , Scholz R. 
Published: March 2005

AbstractFor centuries, glass has been a very well‐known material. Even today new interesting applications are discovered. As described in the paper below, micro process engineering enables new approaches in the development and production of chemical compounds. Since there are many examples of aggressive chemicals which have to be handled, an inert material such as glass is of great interest.
The Kinetic Acidity of Oligofluorobenzenes Correlated with Their Gas Phase Deprotonation Energies
Authors: Schlosser Manfred , Marzi Elena 
Published: March 2005

AbstractThe relative reactivities of fluorobenzene, all di‐, tri‐, and tetrafluorobenzenes and pentafluorobenzene toward sec‐butyllithium have been assessed in tetrahydrofuran at −100 °C. At this temperature no subsequent transmetalation reactions take place but those compromise the outcome of the competition experiments if the latter are conducted at −75 °C. The rates determined at −100 °C reflect the basicity differences between the naked (oligo)fluorophenyl anions to the extent of 10 %.
Intramolecular Electron Transfer between Tyrosine and Tryptophan Photosensitized by a Chiral π,π* Aromatic Ketone
Authors: Galian Raquel E. , Pastor‐Pérez Lourdes , Miranda Miguel A. , Pérez‐Prieto Julia 
Published: March 2005

AbstractThe photochemical reaction of Trp and Tyr and related peptides with Suprofen (SUP) as sensitizer in H2O/CH3CN (28:1 v/v) solutions has been studied by time‐resolved spectroscopy. The results show that SUP induces oxidation of both Trp and Tyr, as well as intramolecular‐ET reactions in the related peptides. The influence of photosensitizer configuration on the involved processes has been studied by using the enantiomerically pure compounds. A significant chiral recognition is observed in which the concentration of the radicals formed after triplet quenching depends on the configuration of the chiral center; the quenching process is higher when using the (R)‐SUP enantiomer.
Giant meso–meso‐Linked Porphyrin Arrays of Micrometer Molecular Length and Their Fabrication
Authors: Aratani Naoki , Takagi Akihiko , Yanagawa Yoshiki , Matsumoto Takuya , Kawai Tomoji , Yoon Zin Seok , Kim Dongho , Osuka Atsuhiro 
Published: March 2005

AbstractOn the basis of the AgI‐promoted coupling reaction of zinc(II)–5,15‐bis(3,5‐dioctyloxyphenyl)porphyrin Z1, chain elongation has been attempted by using a stepwise doubling approach, which provides Z2, Z4, Z8, Z16, Z32, Z64, Z128, Z256, Z384, and Z512. The porphyrin arrays up to Z128 are sufficiently soluble in CHCl3 and THF despite their very long molecular lengths and rodlike structures, while the arrays over Z128 show a significant drop in solubility and stability. The discrete porphyrin arrays thus isolated were characterized by means of 1H NMR spectroscopy, matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) mass spectrometry, UV/Vis spectroscopy, gel‐permeation chromatography (GPC), cyclic voltammetry (CV), single‐crystal X‐ray crystallography, scanning tunneling microscopy (STM), and atomic force microscopy (AFM). Contrary to expected linear conformations of the arrays Z n (where n is the number of porphyrins), the single molecular images of Z128, Z256, and Z512 revealed largely bent structures; this finding indicates the substantial conformational flexibility of Z n. We also exploited an effective synthetic route by means of which Z n can be fabricated with a thiol‐protected aryl group to provide Z n S2 through Z n Br2, by bromination with N‐bromosuccinimide and subsequent Pd‐catalyzed Suzuki–Miyaura arylation. Finally, the reaction of Z256 provided Z512, Z768, and Z1024. Collectively, this work provides an important milestone in the preparation of sub‐microscale discrete organic molecules and the fabrication of molecular‐based materials, hence significantly contributing to device applications.
Carbohydrates as the Next Frontier in Pharmaceutical Research
Authors: Werz Daniel B. , Seeberger Peter H. 
Published: March 2005

AbstractSynthetic carbohydrates and glycoconjugates are used to study their roles in biological important processes such as inflammation, cell–cell recognition, immunological response, metastasis, and fertilization. The development of an automated oligosaccharide synthesizer greatly accelerates the assembly of complex, naturally occurring carbohydrates as well as chemically modified oligosaccharide structures and promises to have major impact on the field of glycobiology. Tools such as microarrays, surface plasmon resonance spectroscopy, and fluorescent carbohydrate conjugates to map interactions of carbohydrates in biological systems are presented. Case studies of the successful application of carbohydrates as active agents are discussed, for example, fully synthetic oligosaccharide vaccines to combat tropical diseases (e.g., malaria), bacterial infections (e.g., tuberculosis), viral infections such as HIV, and cancer. Aminoglycosides serve as examples of drugs acting through carbohydrate–nucleic‐acid interactions, while heparin works by carbohydrate–protein interactions. A general, modular strategy for the complete stereoselective synthesis of defined heparin oligosaccharides is presented. A carbohydrate‐functionalized fluorescent polymer has been shown to detect miniscule amounts of bacteria faster than commonly used methods.
Donor‐Substituted Cyanoethynylethenes: π‐Conjugation and Band‐Gap Tuning in Strong Charge‐Transfer Chromophores
Authors: Moonen Nicolle N. P. , Pomerantz William C. , Gist Robin , Boudon Corinne , Gisselbrecht Jean‐Paul , Kawai Tsuyoshi , Kishioka Atsushi , Gross Maurice , Irie Masahiro , Diederich François 
Published: March 2005

AbstractAn extensive series of silyl‐protected cyanoethynylethenes (CEEs) and N,N‐dimethylanilino donor‐substituted CEEs have been synthesized. More extended chromophores were constructed by selective silyl deprotection and subsequent oxidative acetylenic coupling. The strong electron‐accepting nature of the CEEs was revealed by a combination of 13C NMR spectroscopic and electrochemistry measurements. Donor‐substituted CEEs display strong intramolecular charge‐transfer (CT) character, resulting in intense, bathochromically shifted CT bands in the UV/Vis spectrum. Their structural diversity establishes them as suitable models for the study of π‐conjugation and band gap tuning in strong charge‐transfer chromophores. The extent of π‐conjugation in the donor‐substituted CEEs was investigated by a combination of ground‐state techniques, such as X‐ray crystallography, electrochemistry, B3 LYP calculations, and NMR spectroscopy. The comparison of these ground‐state results with the features observed in the UV/Vis spectra reveals that—contrary to expectations—more extensive π‐conjugation can lead to larger band gaps in molecules with strong donor and acceptor moieties.
Screening women at high risk for breast cancer with mammography and magnetic resonance imaging
Authors: Lehman Constance D. , Blume Jeffrey D. , Weatherall Paul , Thickman David , Hylton Nola , Warner Ellen , Pisano Etta , Schnitt Stuart J. , Gatsonis Constantine , Schnall Mitchell ,   for the International Breast MRI Consortium Working Group
Published: March 2005

AbstractBACKGROUNDThe authors compared the performance of screening mammography versus magnetic resonance imaging (MRI) in women at genetically high risk for breast cancer.METHODSThe authors conducted an international prospective study of screening mammography and MRI in asymptomatic, genetically high‐risk women age ≥ 25 years. Women with a history of breast cancer were eligible for a contralateral screening if they had been diagnosed within 5 years or a bilateral screening if they had been diagnosed > 5 years previously. All examinations (MRI, mammography, and clinical breast examination [CBE]) were performed within 90 days of each other.RESULTSIn total, 390 eligible women were enrolled by 13 sites, and 367 women completed all study examinations. Imaging evaluations recommended 38 biopsies, and 27 biopsies were performed, resulting in 4 cancers diagnosed for an overall 1.1% cancer yield (95% confidence interval [95%CI], 0.3–2.8%). MRI detected all four cancers, whereas mammography detected one cancer. The diagnostic yield of mammography was 0.3% (95%CI, 0.01–1.5%). The yield of cancer by MRI alone was 0.8% (95%CI, − 0.3–2.0%). The biopsy recommendation rates for MRI and mammography were 8.5% (95%CI, 5.8–11.8%) and 2.2% (95%CI, 0.1–4.3%).CONCLUSIONSScreening MRI in high‐risk women was capable of detecting mammographically and clinically occult breast cancer. Screening MRI resulted in 22 of 367 of women (6%) who had negative mammogram and negative CBE examinations undergoing biopsy, resulting in 3 additional cancers detected. MRI also resulted in 19 (5%) false‐positive outcomes, which resulted in benign biopsies. Cancer 2005. © 2005 American Cancer Society.
Serum parathyroid hormone‐related peptide is associated with systemic inflammation and adverse prognosis in gastroesophageal carcinoma
Authors: Deans Chris , Wigmore Stephen , Paterson‐Brown Simon , Black James , Ross James , Fearon Kenneth C. H. 
Published: March 2005

AbstractBACKGROUNDParathyroid hormone‐related peptide (PTHrP) is a tumor‐derived circulating factor that has been associated with hypercalcemia of malignancy. The role of PTHrP as a prognostic indicator remains unclear. Studies suggest that it may function as a growth factor; and, recently, the ability of PTHrP to induce cytokine expression has been described. PTHrP also has been proposed as a procachectic factor. In this study, the authors investigated the prognostic value of PTHrP in patients who had gastroesophageal carcinoma without hypercalcemia and determined whether PTHrP was associated with systemic inflammation and adverse nutritional status.METHODSPatients were recruited at the time of diagnosis. Serum was collected for determination of c‐terminal fragment PTHrP (cPTHrP) levels (by radioimmunoassay) and calcium levels as well as levels of serum cytokines and acute‐phase proteins (with an enzyme‐linked immunosorbent assay). Nutritional assessment of patients was undertaken at the same time as serum collection. Patients underwent routine staging, and survival duration was recorded.RESULTSOne hundred fifty‐one patients with esophagogastric carcinoma were recruited. Six of 151 patients (4.0%) patients were hypercalcemic, and 26 patients (17.2%) had elevated serum cPTHrP levels. There was no association between the cPTHrP level and either serum calcium concentrations (P = 0.72) or adverse nutritional status. Elevated cPTHrP, however, was associated with significantly higher serum levels of soluble tumor necrosis factor receptor (P = 0.008) and with significantly lower levels of transferrin (P = 0.009) and albumin (P = 0.02). There was also a weak association with C‐related protein levels (P = 0.06). Elevated cPTHrP levels also were associated with an adverse prognosis, as determined by reduced survival duration, on univariate analysis (P = 0.038), but not on multivariate analysis (P = 0.15).CONCLUSIONSElevated serum cPTHrP levels were present in approximately 17% of patients with gastroesophageal carcinoma in the absence of hypercalcemia and was associated with markers of systemic inflammation and with an adverse prognosis. Cancer 2005. © 2005 American Cancer Society.
A Phase I clinical trial of ixabepilone (BMS‐247550), an epothilone B analog, administered intravenously on a daily schedule for 3 days
Authors: Zhuang Sen H. , Agrawal Manish , Edgerly Maureen , Bakke Susan , Kotz Herb , Thambi Paul , Rutt Ann , Balis Frank M. , Bates Susan , Fojo Tito 
Published: March 2005

AbstractBACKGROUNDThe epothilones are a novel class of microtubule‐stabilizing agents. Ixabepilone (BMS‐247550; NSC 710428) is a semisynthetic analog of the natural product epothilone B. The authors conducted a Phase I study by administering ixabepilone to patients as a 1‐hour intravenous infusion daily for 3 consecutive days every 21 days.METHODSTwenty‐six patients were enrolled and received ixabepilone at a starting dose of 8 or 10 mg/m2 per day for 3 consecutive days.RESULTSOne hundred and nineteen cycles were administered to 26 patients. The maximum‐tolerated dose was 8 mg/m2 per day of ixabepilone administered as a 1‐hour intravenous infusion daily for 3 consecutive days every 21 days. The dose‐limiting toxicity (DLT) was neutropenia. Other nonhematologic Grade 3 toxicities included fatigue (3 cycles), hyponatremia (1 cycle), anorexia (1 cycle), ileus (1 cycle), stomatitis (1 cycle), and emesis (1 cycle). Prolonged disease stabilization was observed in patients with mesothelioma, ovarian carcinoma, and renal cell carcinoma.CONCLUSIONSThe recommended Phase II dose of ixabepilone on the daily schedule for 3 days was 8–10 mg/m2 per day. Neutropenia was the DLT. Peripheral neuropathy was mild, even after multiple cycles of therapy, and was not dose limiting. Cancer 2005. Published 2005 by the American Cancer Society.
Refractive index measurement in viable cells using quantitative phase‐amplitude microscopy and confocal microscopy
Authors: Curl Claire L. , Bellair Catherine J. , Harris Trudi , Allman Brendan E. , Harris Peter J. , Stewart Alastair G. , Roberts Ann , Nugent Keith A. , Delbridge Lea M. D. 
Published: March 2005

AbstractBackgroundThe refractive index (RI) of cellular material provides fundamental biophysical information about the composition and organizational structure of cells. Efforts to describe the refractive properties of cells have been significantly impeded by the experimental difficulties encountered in measuring viable cell RI. In this report we describe a procedure for the application of quantitative phase microscopy in conjunction with confocal microscopy to measure the RI of a cultured muscle cell specimen.MethodsThe experimental strategy involved calculation of cell thickness by using confocal optical sectioning procedures, construction of a phase map of the same cell using quantitative phase microscopy, and selection of cellular regions of interest to solve for the cell RI.ResultsMean cell thickness and phase values for six cell regions (five cytoplasmic and one nuclear) were determined. The average refractive index calculated for cytoplasmic and nuclear regions was 1.360 ± 0.004. The uncertainty in the final RI value represents the technique measurement error.ConclusionsThe methodology we describe for viable cell RI measurement with this prototype cell has broad generic application in the study of cell growth and functional responses. The RI value we report may be used in optical analyses of cultured cell structure and morphology. © 2005 Wiley‐Liss, Inc.
NOR expression increases on metaphase chromosomes of down syndrome lymphocytes in concordance with mitogen concentration in culture medium
Authors: Imamoglu Nalan , Demirtas Halil , Donmez‐Altuntas Hamiyet , Hamurcu Zuhal , Ilten Ali 
Published: March 2005

AbstractBackgroundRegulation of nucleolus organizer region (NOR) expression in trisomy 21 (Down syndrome [DS]) cells is not fully explained. This work compared NOR expression on metaphase chromosomes in gradiently stimulated lymphocytes from DS patients with those from healthy controls.MethodConventional peripheral blood culture (72 h) and chromosomal preparation procedures were used except that blood samples from each individual were cultivated in the same but gradiently increasing concentrations (0.37, 0.75, 1.48, and 2.21 ml) of phytohemagglutinin (PHA) per 100 ml of medium. One hundred consecutive metaphases per concentration were analyzed for scoring the means of the active NORs bearing chromosomes (AgNOR+ chromosome) per individual and per concentration.ResultsIn contrast to healthy controls (n = 24), AgNOR+ chromosomal number in lymphocytes from 30 DS patients increased in concordance to the gradient of PHA concentration in the culture medium.ConclusionDS lymphocytes do not downregulate their NOR expression in the limit of control cells. This in vitro result may serve as a clue for the explanation of the DS phenotype due to the wasted energy in producing unnecessary rRNA transcripts and AgNOR proteins in utero during organogenesis. These results also indicate that precautions must be used in routine work of NOR evaluation/interpretation in DS lymphocytes. © 2005 Wiley‐Liss, Inc.