bluuebunny/crossref_metadata_2025 huggingface dataset:
3‐year follow‐up of 100 consecutive coronary bifurcation lesions treated with Taxus stents and the crush technique
Authors: Chue Colin D. , Routledge Helen C. , Ludman Peter F. , Townend Jonathan N. , Epstein Andrew C.R. , Buller Nigel P. , Doshi Sagar N.
Published: August 2009

Objectives: To determine the 3 year safety and efficacy of crush‐stenting with paclitaxel‐eluting stents. Background: The optimum two‐stent strategy for treatment of coronary bifurcation lesions is undetermined. Crush‐stenting is advocated to minimize restenosis through complete circumferential stent coverage; long‐term follow‐up data are lacking. Methods and Results: In a single center prospective registry, 100 consecutive patients with bifurcation lesions were treated with the Crush technique. The vast majority (93%) were true bifurcations, predominantly involving the left anterior descending and diagonal arteries. Technical success was 98%. Final kissing balloon dilatation, which became standard practice during the study, was attempted in 68 patients and successful in 51. Abciximab was used in all cases. There were no peri‐procedural stent thromboses. Follow‐up was 100% at 3 years. Symptom‐driven target lesion revascularisation was 8% at 3 years. Cumulative 3‐year major adverse cardiac events was 28% (7 cardiac deaths, 15 myocardial infarctions, 11 target vessel revascularisations). Absence of a final kissing inflation predicted repeat revascularisation but not death, infarction or stent thrombosis. Three probable stent thromboses occurred, of which two were very late. Conclusion: Where a two‐stent bifurcation strategy is required, Crush‐stenting with paclitaxel‐eluting stents is safe and effective in the long‐term. Failure to perform a final kissing dilatation increases the likelihood of revascularisation but not other adverse events. © 2009 Wiley‐Liss, Inc.
Tibioperoneal trunk pseudoaneurysm coil embolization
Authors: Micari Antonio , Vadalà Giuseppe
Published: August 2009

Introduction: Pseudoaneurysms of the tibioperoneal trunk are rare and can be limb threatening. There are various treatment options to seal pseudoaneuryms both percutaneously and via open surgery. Case report: Description of the case of a large tibioperoneal trunk pseudoaneurysm that has been successfully treated by coil embolization in a patient with a previous endocarditys. Conclusion: Endovascular treatment of pseudoaneurysm should be considered as an alternative treatment option to open surgery. © 2010 Wiley‐Liss, Inc.
Impact of the prehospital ECG on door‐to‐balloon time in ST elevation myocardial infarction
Authors: Rao Anjani , Kardouh Youssef , Darda Saba , Desai Devang , Devireddy Lingareddy , Lalonde Thomas , Rosman Howard , David Shukri
Published: August 2009

Background:

National guidelines have been set to achieve door‐to‐balloon time (D2B) is less than 90 minutes to improve outcomes for patients with STEMI. The purpose of this study is to see if a more aggressive approach utilizing prehospital ECGs could improve reperfusion times.

Methods:

The EMS personnel obtained a 12‐lead ECG during initial assessment in the field from patients with chest pain. The ECG was immediately transmitted to the ER physician by cellular link to a computer receiving station. The ER physician reviewed the ECG digital tracing. The cardiac catheterization laboratory (CCL) team was activated from the patients' homes. Patients were transported from the field directly to the CCL by EMS bypassing the emergency department.

Results:

The mean D2B for patients with initial ECG in hospital in all three hospitals combined was 90.5 minutes, compared to 60.2 minutes in patients with prehospital ECG. (P < 0.0001). When analyzing the mean D2B in regards to times of presentation, we found a significant reduction in mean D2B in patients presenting during working hours (75 minutes) compared with those presenting during off hours (98 minutes) in the control group. However, with the use of prehospital ECGs, there was a significant reduction in D2B regardless of what time the patient arrived in the ER.

Conclusions:

Utilizing the prehospital ECG as a tool to bypass ER triage significantly decreases D2B times in patients with STEMI. This technology has the potential to substantially expedite reperfusion therapy in patients with STEMI. © 2009 Wiley‐Liss, Inc.
Bronchopulmonary fistula closure with an Amplatzer Multi‐Fenestrated Septal Occluder
Authors: Boudoulas Konstantinos Dean , Elinoff Jason , Resar Jon R.
Published: August 2009

Bronchopulmonary fistula, a communication between the bronchial airway and the pleural space, is associated with increased morbidity and mortality often requiring surgical therapy. A successful closure of a fistula from the posterior trachea to the right apical pleural space in a 60‐year‐old man with a history of Barrett's esophagus, esophagectomy, multiple pulmonary infections, and right upper lobectomy using an Amplatzer Multi‐Fenestrated Septal Occluder via a transbronchial approach is reported. © 2009 Wiley‐Liss, Inc.
Analysis of Coherent Heteroclustering of Different Dyes by Use of Threoninol Nucleotides for Comparison with the Molecular Exciton Theory
Authors: Fujii Taiga , Kashida Hiromu , Asanuma Hiroyuki
Published: August 2009

To test the molecular exciton theory for heterodimeric chromophores, various heterodimers and clusters, in which two different dyes were stacked alternately, were prepared by hybridizing two oligodeoxyribonucleotides (ODNs), each of which tethered a different dye on D‐threoninol at the center of the strand. NMR analyses revealed that two different dyes from each strand were stacked antiparallel to each other in the duplex, and were located adjacent to the 5′‐side of a natural nucleobase. The spectroscopic behavior of these heterodimers was systematically examined as a function of the difference in the wavelength of the dye absorption maxima (Δλmax). We found that the absorption spectrum of the heterodimer was significantly different from that of the simple sum of each monomeric dye in the single strand. When azobenzene and Methyl Red, which have λmax at 336 and 480 nm, respectively, in the single strand (Δλmax=144 nm), were assembled on ODNs, the band derived from azobenzene exhibited a small hyperchromism, whereas the band from Methyl Red showed hypochromism and both bands shifted to a longer wavelength (bathochromism). These hyper‐ and hypochromisms were further enhanced in a heterodimer derived from 4′‐methylthioazobenzene and Methyl Red, which had a much smaller Δλmax (82 nm; λmax=398 and 480 nm in the single‐strand, respectively). With a combination of 4′‐dimethylamino‐2‐nitroazobenzene and Methyl Red, which had an even smaller Δλmax (33 nm), a single sharp absorption band that was apparently different from the sum of the single‐stranded spectra was observed. These changes in the intensity of the absorption band could be explained by the molecular exciton theory, which has been mainly applied to the spectral behavior of H‐ and/or J‐aggregates composed of homo dyes. However, the bathochromic band shifts observed at shorter wavelengths did not agree with the hypsochromism predicted by the theory. Thus, these data experimentally verify the molecular exciton theory of heterodimerization. This coherent coupling among the heterodimers could also partly explain the bathochromicity and hypochromicity that were observed when the dyes were intercalated into the duplex.
Crystal Structure of the T(6‐4)C Lesion in Complex with a (6‐4) DNA Photolyase and Repair of UV‐Induced (6‐4) and Dewar Photolesions
Authors: Glas Andreas F. , Schneider Sabine , Maul Melanie J. , Hennecke Ulrich , Carell Thomas
Published: August 2009

UV‐light irradiation induces the formation of highly mutagenic lesions in DNA, such as cis‐syn cyclobutane pyrimidine dimers (CPD photoproducts), pyrimidine(6‐4)pyrimidone photoproducts ((6‐4) photoproducts) and their Dewar valence isomers ((Dew) photoproducts). Here we describe the synthesis of defined DNA strands containing these lesions by direct irradiation. We show that all lesions are efficiently repaired except for the T(Dew)T lesion, which cannot be cleaved by the repair enzyme under our conditions. A crystal structure of a T(6‐4)C lesion containing DNA duplex in complex with the (6‐4) photolyase from Drosophila melanogaster provides insight into the molecular recognition event of a cytosine derived photolesion for the first time. In light of the previously postulated repair mechanism, which involves rearrangement of the (6‐4) lesions into strained four‐membered ring repair intermediates, it is surprising that the not rearranged T(6‐4)C lesion is observed in the active site. The structure, therefore, provides additional support for the newly postulated repair mechanism that avoids this rearrangement step and argues for a direct electron injection into the lesion as the first step of the repair reaction performed by (6‐4) DNA photolyases.
Experimental aspects of solid state circular dichroism
Authors: Castiglioni Ettore , Biscarini Paolo , Abbate Sergio
Published: August 2009

The interest of circular dichroism in the solid state is stimulated by several needs, such as the desire to get solvent free spectra, the insolubility of the sample or the intrinsic process in which the sample itself is prepared or manipulated. We approach the argument on the basis of the sampling technique, since each different case calls for specific care in getting proper results. Chirality 21:E28–E36, 2009. © 2009 Wiley‐Liss, Inc.
More tumor‐affected lymph nodes because of the sentinel lymph node procedure but no stage migration, because the 2002 TNM classifies small tumor deposits as pathologic N0 breast cancer
Authors: Bolster Marieke J. , Bult Peter , Wauters Carla A. P. , Strobbe Luc J. A. , Peer Petronella G. M. , Wobbes Theo , Tjan‐Heijnen Vivianne C. G.
Published: September 2009

BACKGROUND:

Intensified examination of the sentinel lymph node (SN) may result in increased detection of tumor‐affected lymph nodes. The authors of this report hypothesized that the introduction of the SN procedure has led to stage migration because of the intensified workup of SNs by pathologists.

METHODS:

After the introduction of the SN procedure, 360 patients with operable breast cancer were included prospectively from 2 large hospitals (Hospital A and Hospital B). The prospectively included patients (the “SN era” group) were compared with 88 historic controls from the year 1994 who were diagnosed with primary breast cancer before introduction of the SN procedure.

RESULTS:

After correcting for classic clinical and pathologic prognostic factors in a multiple logistic regression analysis, the detection frequency of lymph node involvement was significantly higher in the SN era group compared with historic controls (P = .04). However, when using the 2002 TNM classification, in which isolated tumor cells (≤0.2 mm) were categorized as lymph node‐negative disease, no stage migration was observed (P = .98). Also, when analyzing both hospitals (Hospital A vs Hospital B) separately with respect to lymph node involvement, there was no difference, between the SN era and the historic controls (P = .79 and P = .69, respectively). This remained nonsignificant after the analysis was corrected for patient and primary tumor characteristics (P = .85 and P = .66, respectively).

CONCLUSIONS:

Introduction of the SN procedure has led to the detection of more tumor‐affected lymph nodes because of the intensified workup of SNs by pathologists. However, stage migration did not occur when tumor deposits of ≤0.2 mm were categorized as lymph node‐negative disease, according to the 2002 TNM classification. Cancer 2009. © 2009 American Cancer Society.
Titania Nanocrystals and Adsorptive Nanoporous Polymer Composites: An Enrichment and Degradation System
Authors: Zhang Yonglai , Wei Shu , Zhang Wei , Xu Yi‐Jun , Liu Sen , Su Dang Sheng , Xiao Feng‐Shou
Published: August 2009

Composites of titania nanocrystals and adsorptive nanoporous polymers are synthesized via a two‐step solvothermal pathway. These composites are developed as bifunctional materials for both the adsorption of organic compounds and photocatalysis, providing an enrichment and degradation system for the removal of environmental pollutants. The anatase‐phase titania nanoparticles are homogeneously dispersed in the matrix of the nanoporous polymers. The composites exhibit nanoporous structures, high surface areas, and excellent stabilities. Experimental results show that the composites have excellent adsorptive properties for organic compounds in water and air and high photocatalytic activities under UV irradiation. These bifunctional materials may have promising applications in environmental protection.
Environmental enrichment influences survival rate and enhances exploration and learning but produces variable responses to the radial maze in old rats
Authors: Bell J.A. , Livesey P.J. , Meyer J.F.
Published: August 2009

Wistar rats at 7 (mature), 16 (aging), and 22 (old) months of age spent 70 days in normal laboratory (Social), impoverished (Isolated) or dynamic Enrichment cages. The Enriched cage emphasized spatial re‐arrangements of significant items, and the learning of new routes. Subsequently, Enriched rats at all ages entered a novel environment and escaped from a bright light with significantly shorter latencies than rats from either of the other environments. Mature, aging and some of the old Enriched rats also significantly outperformed their Isolated and Social counterparts in the radial maze. However old Enriched and Isolated animals showed significant variability in relation to the measure of the proportion reaching criterion on this task, and a significantly lower proportion than of old Social rats reached criterion. Enriched rats had a significantly higher survival rate than Social and Isolated animals. These findings are discussed in terms of learning efficiency and behaviors that conserve energy and thereby enhance survival. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 564–578, 2009.
PNSO Ligands as a Tool to Study Metal Bonding of Electron‐Deficient Sulfinyl Groups
Authors: Revés Marc , Riera Antoni , Verdaguer Xavier
Published: August 2009

A family of N‐phosphanylsulfinamide (PNSO) ligands with electron‐deficient sulfinyl groups was synthesized. Reaction with Co2–alkyne complexes yields P,S‐bridged complexes. These complexes were used to study the metal bonding of different sulfinyl groups. IR spectroscopy, X‐ray analysis, and Pauson–Khand reactivity studies indicated that electron‐deficient sulfinyl groups provide enhanced S metal bonding. The mean CO stretching frequencies (Δν) for these complexes closely correlates with the χi parameter computed by Tolman for phosphane ligands. Among the studied sulfinyl groups, the trifluoromethyl PNSO ligand afforded the strongest sulfur–metal bond. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Coordination Induction of Nonlinear Molecular Shape in Mesomorphic and Luminescent ZnII Complexes Based on Salen‐Like Frameworks
Authors: Pucci Daniela , Aiello Iolinda , Bellusci Anna , Crispini Alessandra , Ghedini Mauro , La Deda Massimo
Published: August 2009

A series of tetradentate dimeric salicylaldimine ligands (H2LnRm) with terminal chains of variable length (Rm) and a central flexible (CH2)n spacer (Ln = 10 and 12) was synthesized. For all ligands, according to their rod‐like molecular shape, mesomorphism characteristic of calamitic systems (nematic and smectic C phases) is observed. The reaction with ZnII acetate dihydrate afforded a series of ZnLnRm derivatives (1–6) that show mesomorphic behaviour only in the presence of the longest terminal tails (R12). Interestingly, the flexibility of the very long spacer in the central core and the presence of the tetrahedral ZnII centre introduce nonlinearity in the central part of the molecule, responsible for the appearance of an intercalated smectic C mesophase. Moreover, the coordination of the ZnII ion to the salen‐like framework induces, in all the corresponding complexes, interesting blue‐light‐emitting properties at room temperature in dichloromethane solution (EQY in the 19–22 % range at about 450 nm), as well as in the solid (EQY: 9 % at about 450 nm) or, when present, in the mesophase (EQY 8 % at 440 nm).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Analysis of the Interaction between Adenine Nucleobase and Metal‐Malonato Complexes (Eur. J. Inorg. Chem. 26/2009)
Authors: Pérez‐Yáñez Sonia , Castillo Oscar , Cepeda Javier , García‐Terán Juan P. , Luque Antonio , Román Pascual
Published: August 2009

The cover picture shows the paddle‐wheel motif adopted by the dinuclear complexes in which the metal centres are held together by bridging malonato and bridging neutral adenine ligands, the countercomplementarity of the bridging ligands responsible for their ferromagnetic behaviour, and the molecular recognition processes that take place between the protonated adeninium cations and the anionic copper‐malonato fragments. Details are discussed in the article by O. Castillo, A. Luque et al. on p. 3889 ff.
A Novel, Highly Efficient, One‐Pot Synthesis of 1,4‐Dihydroquinoline Derivatives in the Presence of a Pd(OAc)2/DABCO Catalytic System
Authors: Wu Xiao‐Jin , Xu Xiao‐Ping , Su Xiao‐Ming , Chen Gang , Zhang Yong , Ji Shun‐Jun
Published: August 2009

The Pd(OAc)2/DABCO catalytic system was first found to be highly efficient for C–N cross‐coupling reactions. With the aid of this transformation, a variety of new 1,4‐dihydroquinoline derivatives were synthesized from o‐halobenzaldehydes and various β‐enaminones in good to excellent yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Electrokinetic trapping using titania nanoporous membranes fabricated using sol–gel chemistry on microfluidic devices
Authors: Hoeman Kurt W. , Lange Jeffrey J. , Roman Gregory T. , Higgins Daniel A. , Culbertson Christopher T.
Published: August 2009

We have developed a new method for analyte preconcentration on a microfluidic device using a porous membrane fabricated via sol–gel chemistry. These porous membranes were fabricated within the channels of glass microfluidic devices exploiting laminar flow to bring an alcoholic sol–gel precursor (titanium isopropoxide in 2‐propanol) into contact with an alcohol–water solution at a channel cross intersection. These two streams reacted at the fluidic interface to form a porous titania membrane. The thickness of the membrane could be altered by changing the [H2O]. Analyte concentration was accomplished by applying a voltage across the titania membrane. The level of analyte enrichment was monitored, and enrichment factors of above 4000 in 400 s were obtained for 2,7‐dichlorofluorescein.
Design, fabrication and characterization of nano‐filters in silicon microfluidic channels based on MEMS technology
Authors: Chen Xing , Cui Dafu , Chen Jian
Published: August 2009

Since most clinical assays are performed on cell‐free serum or plasma, micro‐analytical systems for blood tests require integrated on‐chip microfluidics for the isolation of plasma or serum from crude blood samples. In this paper, we present a crossflow filtration method using novel silicon nano‐filters for plasma separation. The microfluidic chip is made of a silicon substrate containing micropillar arrays, feed channels, side channels and nano‐gap structures, sealed with a PDMS‐glass compound cover. The design of the silicon filtration structures were optimized using numerical analysis and the optimal MEMS fabrication procedures were obtained. The filtration structures including nano‐filters were characterized using SEM and subsequently used to isolate plasma from whole blood in a continuous manner. Compared with micro‐gap structures in silicon microfluidic channels, the nano‐gap structures have been used to separate plasma from whole blood samples with higher selectivity, where a maximum plasma selectivity of 97.7% has been obtained. Common problems of clogging and jamming in filtration applications have seldom been noticed in our device. The presented microfluidic filtration device for plasma isolation could be integrated into μTAS for point‐of‐care diagnostics in the near future.
Exceeding 20 000‐fold concentration of protein by the on‐line isotachophoresis concentration in poly(methyl methacrylate) microchip
Authors: Wang Jun , Zhang Yong , Mohamadi Mohamad Reza , Kaji Noritada , Tokeshi Manabu , Baba Yoshinobu
Published: August 2009

In this research, a simple on‐line microchip gel electrophoresis with ITP was applied for the concentration and separation of BSA and its immunoassay complex with mAb in a single cross form PMMA microchip. We investigated the ITP concentration effect in PMMA MCE using combination of leading electrolytes, terminating electrolytes and other factors. We realized an ITP‐based concentration and separation of BSA and its immunoassay complexes in standard cross‐channel microchip gel electrophoresis, which exceeded 2000‐fold concentration of BSA immunocomplex using Tris‐H3PO4 as a leading electrolyte and Tris‐γ‐amino butyric acid as a terminating electrolyte. In addition, we also realized concentration of BSA sample in water, which was more than 20 000‐fold and was the result of the concentration effect from combining ITP and the sample stacking techniques.
A microfabricated CE chip for DNA pre‐concentration and separation utilizing a normally closed valve
Authors: Kuo Chen‐Hua , Wang Jung‐Hao , Lee Gwo‐Bin
Published: August 2009

A simple, sequential DNA pre‐concentration and separation method by using a micro‐CE chip integrated with a normally closed valve, which is activated by pneumatic suction, has been developed. The CE chip is fabricated using PDMS. A surface treatment technique for coating a polymer bilayer with an anionic charge is applied to modify the surface of the microchannel. A normally closed valve with anionic surface charges forms a nanoscale channel that only allows the passage of electric current but traps the DNA samples so that they are pre‐concentrated. After the pre‐concentration step, a pneumatic suction force is applied to the normally closed valve. This presses down the valve membrane, which reconnects the channels. The DNA samples are then moved into a separation channel for further separation and analysis. Successful DNA pre‐concentration and separation has been achieved. Fluorescent intensity at the pre‐concentration area is increased by approximately 3570 times within 1.9 min of operation. The signals from the separation of ϕX174 DNA/HaeIII markers are enhanced approximately 41 times after 100 s of pre‐concentration time, as compared with the results using a traditional cross‐shaped micro‐CE chip. These results clearly demonstrate that successful DNA pre‐concentration for signal enhancement and separation analysis can be performed by using this new micro‐CE chip.
Electrophoretic total analysis of trace tetracycline antibiotics in a microchip with amperometry
Authors: Lee Kyung‐Sun , Park So‐Hee , Won So‐Young , Shim Yoon‐Bo
Published: August 2009

The preconcentration, separation, and electrochemical detection of a series of tetracycline (TC) antibiotics in a microfluidic channel were preformed. The electrophoretic experimental parameters to analyze TC, oxytetracycline, chlortetracycline, and doxycycline antibiotics were investigated with a cellulose‐dsDNA‐modified carbon paste electrode. Modification of the electrode improved detection performance by enhancing the signal‐to‐noise characteristics without surface fouling of the electrode. Field‐amplified sample stacking and field‐amplified sample injection techniques were employed for on‐chip preconcentration of the TC series. The sensitivity of the method was improved 10 900‐fold when compared with conventional MEKC‐electrochemical detection analysis. The overall recoveries for TC, oxytetracycline, chlortetracycline, and doxycycline were 87, 89, 87, and 81%, respectively, with 6.0% RSD. The limits of detection for the series were estimated between 1.5 and 4.3 nM. Applicability of the method to beef samples was successfully demonstrated.
Manipulation of microfluidic droplets by electrorheological fluid
Authors: Zhang Menying , Gong Xiuqing , Wen Weijia
Published: August 2009

Microfluidics, especially droplet microfluidics, attracts more and more researchers from diverse fields, because it requires fewer materials and less time, produces less waste and has the potential of highly integrated and computer‐controlled reaction processes for chemistry and biology. Electrorheological fluid, especially giant electrorheological fluid (GERF), which is considered as a kind of smart material, has been applied to the microfluidic systems to achieve active and precise control of fluid by electrical signal. In this review article, we will introduce recent results of microfluidic droplet manipulation, GERF and some pertinent achievements by introducing GERF into microfluidic system: digital generation, manipulation of “smart droplets” and droplet manipulation by GERF. Once it is combined with real‐time detection, integrated chip with multiple functions can be realized.
Miniaturized metal semiconductor metal photocurrent system for biomolecular sensing via chemiluminescence
Authors: Lin Chie‐Chieh , Ko Fu‐Hsiang , Chen Chun‐Chi , Yang Yuh‐Shyong , Chang Feng‐Chi , Wu Chung‐Shu
Published: August 2009

A miniaturized metal semiconductor metal photodetector was developed as the core detector for chemiluminescence biosensor. The biosensor utilized the semiconductor manufacturing to fabricate the 83 interdigitated patterns of 250‐nm metal line and 278‐nm space in 100 μm×100 μm active region. The established real‐time detector was operated at 0.4 V to ensure the maximal signal to background ratio of 3600 under illumination intensity of 1.46 mW/cm2. A chemiluminescence in the miniaturized chamber was successfully proposed to determine the model protein concentration in real‐time analysis. Before the emission of light from the catalytic reaction of substrate, the model protein of streptavidin bound to horseradish peroxidase was successfully immobilized onto the sensor surface through the high‐affinity conjugate with biotin. The detection limit of 4.76 nM for streptavidin analysis was obtained under the calibration curve of linear range over 5–100 nM with correlation coefficient of 0.9999.
Enhancement of cellular olfactory signal by electrical stimulation
Authors: Lee Sang Hun , Jeong Se Hoon , Jun Sang Beom , Kim Sung June , Park Tai Hyun
Published: August 2009

The binding of olfactory receptors with odorant molecules initiates olfactory signal transduction, which leads to a cationic influx. In the present study, human embryonic kidney‐293 cells were recombinantly engineered to co‐express olfactory receptors I7 and gustatory cyclic nucleotide gated channels, which increased the cationic influx. The odorant‐induced change in the membrane potential was measured in the extracellular region using microelectrode arrays. A biphasic electrical current stimulation was applied to the cells in order to increase the intrinsic cellular activity. Upon odorants recognition, the electrical cellular activity was enhanced following each electrical stimulation pulse. Compared with odorant‐only stimulation, the electrical stimulation induced up to a fivefold increase in the amplitude of the electrical signal, which was produced in response to the odorants. These results demonstrate that electrical stimulation can enhance cellular activity and increase the response signal for detecting ligand binding. This paradigm of electrical stimulation can be used as a novel method in the field of versatile cell‐based biosensors for detection of specific odorants.
Carbon nanotube‐sensor‐integrated microfluidic platform for real‐time chemical concentration detection
Authors: Yang Li , Li Minglin , Qu Yanli , Dong Zaili , Li Wen J.
Published: August 2009

This paper presents the development of a chemical sensor employing electronic‐grade carbon nanotubes (EG‐CNTs) as the active sensing element for sodium hypochlorite detection. The sensor, integrated in a PDMS‐glass microfluidic chamber, was fabricated by bulk aligning of EG‐CNTs between gold microelectrode pairs using dielectrophoretic technique. Upon exposure to sodium hypochlorite solution, the characteristics of the carbon nanotube chemical sensor were investigated at room temperature under constant current mode. The sensor exhibited responsivity, which fits a linear logarithmic dependence on concentration in the range of 1/32 to 8 ppm, a detection limit lower than 5 ppb, while saturating at 16 ppm. The typical response time of the sensor at room temperature is on the order of minutes and the recovery time is a few hours. In particular, the sensor showed an obvious sensitivity to the volume of detected solution. It was found that the activation power of the sensor was extremely low, i.e. in the range of nanowatts. These results indicate great potential of EG‐CNT for advanced nanosensors with superior sensitivity, ultra‐low power consumption, and less fabrication complexity.
Effects of embedded sub‐micron pillar arrays in microfluidic channels on large DNA electrophoresis
Authors: Chan Yick Chuen , Zohar Yitshak , Lee Yi‐Kuen
Published: August 2009

A study of the influences of embedding artificial structures in a microfluidic device for CE with a free buffer solution is presented. Compared with conventional slab‐gel electrophoresis, three major additional effects on the overall system performance are identified when sub‐micron pillar arrays are integrated into a standard CE microsystem. Since DNA molecules have to migrate in‐between and interact with the pillars, pillar geometry is first demonstrated to have a direct impact on the DNA motion pattern. Electric field re‐distribution is another inevitable outcome when features of sub‐micron dimensions are placed inside a microchannel. This effect is verified by a numerical simulation tool. Furthermore, the integration of the closely packed sub‐micron structures dramatically increases the surface to volume ratios in the microfluidic device and therefore generates a large EOF. The consequence of these additional influences implies a complexity in the measured DNA velocity and indicates that careful considerations have to be taken when these devices are used for DNA electrokinetics study or electrophoresis theory re‐examination.
Incorporation of electrospun nanofibrous PVDF membranes into a microfluidic chip assembled by PDMS and scotch tape for immunoassays
Authors: Liu Yingyi , Yang Dayong , Yu Tao , Jiang Xingyu
Published: August 2009

This paper demonstrates a microfluidic chip for multiple immunoassays on electrospun (ES) nanofibrous membranes made of PVDF. This microchip enables the detection of multiple pairs of protein–protein interactions in one experiment by crossing parallel arrays of microchannels. This chip uses ESPVDF membrane with high specific surface area as the substrate to adsorb protein for immobilized immunoassays so that increased levels of protein adsorption may lower the LOD in immunoassays. We employ a simple and effective method for chip assembly by scotch tape to incorporate the ESPVDF membrane into the microchip. We believe that the present work will facilitate the development of methods for the on‐site diagnosis of diseases whose detection is based on antigen–antibody recognition, and improve the efficiencies of certain experiments that need to identify tens to hundreds of protein–protein interactions with relatively low cost in the future.
Environmentally friendly surface modification of PDMS using PEG polymer brush
Authors: Zhang Zhaowei , Feng Xiaojun , Luo Qingming , Liu Bi‐Feng
Published: August 2009

A PEG‐NH2‐based environmentally friendly surface modification strategy was developed for PDMS microchips to prevent protein adsorption and to enhance separation performance. PEG‐NH2 was synthesized using a modified synthesis procedure. A two‐step grafting method was used for PDMS modification. FTIR absorption by attenuated total reflection and contact angle measurements verified the successful grafting of PEG‐NH2 onto the PDMS surface. Subsequent EOF Measurements and protein adsorption studies of PEG‐modified PDMS microchips revealed noticeable EOF suppression and resistance to nonspecific protein adsorption for more than 30 days. Separation of four FITC‐labeled amino acids was further demonstrated with high repeatability and reproducibility. Comparison of electrophoresis of 3‐(2‐furoyl)quinoline‐2‐carboxaldehyde‐labeled BSA using PDMS microchips before and after surface modification resulted in significantly improved electrophoretic performance of the PEG‐modified PDMS microchips, suggesting that our PEG grafting method successfully modified PDMS surface property and prevented adsorption of proteins. We expect that this environmentally friendly surface modification method will be useful for future protein separations with long‐term surface stability.
Rapid and efficient proteolysis for proteomic analysis by protease‐immobilized microreactor
Authors: Yamaguchi Hiroshi , Miyazaki Masaya , Honda Takeshi , Briones‐Nagata Maria Portia , Arima Kazunari , Maeda Hideaki
Published: August 2009

Proteolysis is an important part of protein identification in proteomics analysis. The conventional method of in‐solution digestion of proteins is time‐consuming and has limited sensitivity. In this study, trypsin‐ or α‐chymotrypsin‐immobilized microreactors prepared by a microfluidics‐based enzyme‐immobilization technique were studied for rapid sample preparation in proteomic analysis. The kinetic studies for hydrolysis of substrate by microreactors revealed that immobilized proteases had higher hydrolytic efficiency than those performed by in‐solution digestion. The performance of the microreactors was evaluated by digesting cytochrome c and BSA. Protein digestion was achieved within a short period of time (∼5 min) at 30°C without any complicated reduction and alkylation procedures. The efficiency of digestion by trypsin‐immobilized reactor was evaluated by analyzing the sequence coverage, which was 47 and 12% for cytochrome c and BSA, respectively. These values were higher than those performed by in‐solution digestion. Besides, because of higher stability against high concentration of denaturant, the microreactors can be useful for immediate digestion of the denaturated protein. In the present study, we propose a protease‐immobilized microreactor digestion method, which can utilize as a proteome technique for biological and clinical research.
Rapid detection of Mycoplasma pneumonia in a microfluidic device using immunoagglutination assay and static light scattering
Authors: Kim Keesung , Jung Ho‐Sup , Song Jae‐Young , Lee Man‐Ryul , Kim Kye‐Seong , Suh Kahp‐Yang
Published: August 2009

We present real‐time, rapid detection of Mycoplasma pneumonia in PBS inside a Y‐channel PDMS microfluidic device via optical fiber monitoring of latex immunoagglutination. The latex immunoagglutination assay was performed with serially diluted M. pneumonia solutions using highly carboxylated polystyrene particles of 390 and 500 nm diameter conjugated with monoclonal anti‐M. pneumonia. Proximity optical fibers were located around the viewing cell of the device, which were used to measure the increase in 45° forward light scattering of the aggregated particles. The detection limit are slightly less than 50 pg mL−1 both for 390 and 500 nm microspheres and the detection time do not exceed 90 s.
Highly efficient capture and enumeration of low abundance prostate cancer cells using prostate‐specific membrane antigen aptamers immobilized to a polymeric microfluidic device
Authors: Dharmasiri Udara , Balamurugan Subramanian , Adams André A. , Okagbare Paul I. , Obubuafo Annie , Soper Steven A.
Published: August 2009

Prostate tumor cells over‐express a prostate‐specific membrane antigen (PSMA) that can be used as a marker to select these cells from highly heterogeneous clinical samples, even when found in low abundance. Antibodies and aptamers have been developed that specifically bind to PSMA. In this study, anti‐PSMA aptamers were immobilized onto the surface of a capture bed poised within a PMMA, microchip, which was fabricated into a high‐throughput micro‐sampling unit (HTMSU) used for the selective isolation of rare circulating prostate tumor cells resident in a peripheral blood matrix. The HTMSU capture bed consisted of 51 ultra‐high‐aspect ratio parallel curvilinear channels with a width similar to the prostate cancer cell dimensions. The surface density of the PSMA‐specific aptamers on an ultraviolet‐modified PMMA microfluidic capture bed surface was determined to be 8.4×1012 molecules/cm2. Using a linear velocity for optimal cell capture in the aptamer‐tethered HTMSU (2.5 mm/s), a recovery of 90% of LNCaP cells (prostate cancer cell line; used as a model in this example) was found. Due to the low abundance of these cells, the input volume required was 1 mL and this could be processed in ∼29 min using an optimized linear flow rate of 2.5 mm/s. Captured cells were subsequently released intact from the affinity surface using 0.25% w/w trypsin followed by counting individual cells using a contact conductivity sensor integrated into the HTMSU that provided high detection and sampling efficiency (∼100%) and did not require staining of the cells for enumeration.
Identification and separation of DNA‐hybridized nanocolloids by Taylor cone harmonics
Authors: Cheng Xinguang , Basuray Sagnik , Senapati Satyajyoti , Chang Hsueh‐Chia
Published: August 2009

A rapid (minutes) electrospray bead‐based DNA hybridization detection technique is developed by spraying a mixture of hybridized and unhybridized silica nanocolloids. With proper far‐field control by external electrodes, the trajectory of the ejected nanobeads from the electrospray is governed by specific harmonics of the Laplace equation, which select discrete polar angles along well‐separated field maxima near the conducting Taylor cone. Due to Rayleigh fission and evaporation, beads of different size acquire different total charge after ejection and suffer different normal electrophoretic displacement such that they are ejected along well‐separated field maxima and are deposited in distinct rings on an intersecting plane. As the hybridized DNA is of the same dimension as that of the nanocolloid, the nanocolloids are hence easily differentiated from the unhybridized ones. This technique is highly specific as the high shear stress in the microjet shears away any non‐specifically bound DNA from the nanocolloid surface.
Bacteria concentration using a membrane type insulator‐based dielectrophoresis in a plastic chip
Authors: Cho Yoon‐Kyoung , Kim Suhyeon , Lee Kyusang , Park Chinsung , Lee Jeong‐Gun , Ko Christopher
Published: August 2009

We report an insulator‐based (or, electrodeless) dielectrophoresis utilizing microfabricated plastic membranes. The membranes with honeycomb‐type pores have been fabricated by patterning the SU‐8 layer on a substrate which was pretreated with self‐assembled monolayer of octadecyltrichlorosilane for the easy release. The fabricated membrane was positioned between two electrodes and alternating current field was applied for the particle trap experiments. The particle could be trapped due to the dielectrophoresis force generated by the non‐uniformities of the electric fields applied through the membranes with pores. Simulations using CFD‐ACE+(CFD Research, Huntsville, Alabama) suggested that the dielectrophoresis force is stronger in the edge of the pores where the field gradient is highest. The bacteria could be captured on the near edge of the pores when the electric field was turned on and the trapped bacteria could be released when the field was turned off with the release efficiency of more than 93±7%. The maximal trapping efficiency of 66±7% was obtained under the electric fields (E=128 V/mm and f=300 kHz) when the dilute bacteria solution (Escherichia coli: 9.3×103 cell/mL, 0.5 mS/m) flowed with a flow rate of 100 μL/min.
Optical fiber enzymatic biosensor for reagentless measurement of ethylene dibromide
Authors: Reardon Kenneth F. , Campbell Derek W. , Müller Cord
Published: August 2009

A reagentless enzymatic optical biosensor has been constructed to measure the concentration of ethylene dibromide (EDB, 1,2‐dibromoethane), a US EPA Priority Pollutant. This biosensor is based on the haloalkane dehalogenase DhaA, which generates protons as a product of the dehalogenation of EDB. The resulting pH change is detected as a shift in the fluorescence intensity of fluoresceinamine. When layers of fluoresceinamine andRhodococcussp. GJ70 expressing DhaA were immobilized on the tip of an optical fiber, the resulting changes in fluorescence were proportional to the EDB concentration in the range 1–10 μg/L and nonlinear (saturation‐type trend) for concentrations up to 10 mg/L. EDB concentrations as low as 1 μg/L could be detected in aqueous solutions. Both the pH and buffer capacity of the sample had significant effects on the sensor's performance. EDB biosensors were active for at least 37 d, although their sensitivity decreased after 7 d. The biosensor's potential to measure continuously andin situcould make it useful for environmental or water treatment process monitoring systems.
Response surface optimization of mixed substrate solid state fermentation for the production of lovastatin by Monascus purpureus
Authors: Subhagar Seraman , Aravindan Rajendran , Viruthagiri Thangavelu
Published: August 2009

The objective of this work is to enhance the production of lovastatin using Monascus purpureus MTCC 369 in mixed substrate solid state fermentation using various solid substrates and to optimize the combination of the solid substrates by response surface methodology. Solid state fermentation was conducted in a 250 mL Erlenmeyer flask at 30°C for 14 days with initial moisture content of 40% and inoculum size of 10% active culture. Barley, long grain rice and sago starch were found to be the suitable substrates producing maximum lovastatin of 193.7 mg, 190.2 mg and 180.9 mg/g of dry solids. These substrates were further used in various combinations as designed by the central composite design for enhancing the lovastatin production using Monascus purpureus. To the best of our knowledge this is the first report on the production of lovastatin using a mixed substrate solid state fermentation using Monascus purpureus.
The Auxiliary Substrate Concept: From simple considerations to heuristically valuable knowledge
Authors: Babel Wolfgang
Published: August 2009

Microorganisms are used in biotechnology. They are either (i) aim and purpose of a process, e.g. with the production of single cell proteins, or (ii) mean to an end insofar as they serve as a catalyst or “factory” for syntheses (e.g. of products of primary and secondary metabolism, of enzymes and antibiotics) or for the degradation and detoxification of harmful organics and inorganics. In all cases, the efficiency and velocity, finally the productivity, are parameters which essentially determine the economy of the processes. Therefore, search for approaches to optimize these processes is a permanent task and challenge for scientists and engineers. It is shown that the auxiliary substrate concept is suitable to increase the yield coefficients. It is based on the energetic evaluation of organics, on the knowledge that organics as sources of carbon and energy for growth are deficient in ATP and/or reducing equivalents, and says that it is possible to improve the carbon conversion efficiency up to the carbon metabolism determined upper limit. The latter is determined by inevitable losses of carbon along the way of assimilation and anabolism and amounts to about 85% for so‐called glycolytic substrates, e.g. glucose, methanol, and to about 75% for gluconeogenetic substrates, e.g. C2‐substrates (acetic acid, hexadecane). The approach is explained and some experimental examples are presented. By simultaneous utilization of an extra energy source (auxiliary substrate) the yield coefficient can be increased (i) in glucose from about 0.5 to 0.7 g/g (by means of formate), (ii) in acetate from 0.34–0.4 to 0.5–0.65 g/g (by means of formate and thiosulfate, respectively), and (iii) in hexadecane from about 0.94 to 1.26 g/g (by means of formate). The precalculated yield coefficients and mixing ratios agree well with the experimentally attained ones. The approach is easily feasible and economically valuable.
Reactive red azo dye degradation in a UASB bioreactor: Mechanism and kinetics
Authors: Gonzalez‐Gutierrez Linda V. , Escamilla‐Silva Eleazar M.
Published: August 2009

Textile industry uses azo dyes in its processes, which are complex organic molecules that are not easy to be degraded. Reactive dyes are especially difficult to remove from wastewater because of the characteristics of the molecule: one or more azo bonds, naphthalene‐disulfonate, triazine or chloro‐triazine, and phenyl‐amine groups. The degradation of the azo dye reactive red 272 was studied under anaerobic conditions in a hybrid Upflow Anaerobic Sludge Bed reactor (UASB) with an activated carbon bed. An adapted consortium of microorganisms was used in the kinetic study (batch) and to inoculate the UASB reactor. The experimental design identified the main factors determining the dye reduction efficiency are the initial concentration of dye and dextrose (as electron donor) and the residence time in the reactor. Dye reduction rate was decreased as the concentration increases in the wastewater; as a result, a kinetic model with a change from first to second order is proposed. The kinetic study showed that the process is first abiotic (adsorption) and then biotic (biodegradation).
Dynamic modelling of bacterial cellulose formation
Authors: Hornung Michael , Biener Richard , Schmauder Hans‐Peter
Published: August 2009

The interest in cellulose produced by bacteria from surface cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. Unfortunately, the low yield of this production process has limited the commercial usefulness of bacterial cellulose. The aim of this paper is to show the effect of substrate mass transfer on the growth of the bacteria and on their physiological potential for product formation by means of a dynamic mathematical model.
A sharp surface tension modeling method for two‐phase incompressible interfacial flows
Authors: Wang Zhaoyuan , Tong Albert Y.
Published: September 2009

A surface tension implementation algorithm for two‐phase incompressible interfacial flows is presented in this study. The surface tension effect is treated as a jump condition at the interface and incorporated into the Navier–Stokes equation via a capillary pressure gradient. The interface is tracked by a coupled level set and volume‐of‐fluid (CLSVOF) method based on the finite‐volume formulation on a fixed Eulerian grid. It has been shown in a stationary benchmark test the spurious currents are greatly reduced and the sharp pressure jump across the interface is well preserved. Numerical instabilities caused by the sharp treatment on a fixed grid are avoided. Several dynamic tests are performed to further validate the accuracy and versatility of the present method, the results of which are in good agreement with data reported in the literature. Copyright © 2009 John Wiley & Sons, Ltd.
Predicting the signs of forecast errors
Authors: Solferino Nazaria , Waldmann Robert
Published: September 2009

The signs of forecast errors can be predicted using the difference between individuals' forecasts and the average of earlier forecasts of the same variable. It is possible to improve forecasts without worsening any. It is difficult to reconcile this result with the rational expectations hypothesis because the average of earlier forecasts is in the information set of the forecasters. Copyright © 2009 John Wiley & Sons, Ltd.