bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Aspects of Microfluidic Devices: Moving Fluids and Building Devices
Authors: Weigl Bernhard H. , Bardell Ron L. , Cabrera Catherine
Published: February 2008

This chapter provides insight into practical aspects of microfluidic device design, such as fluid movement, device construction, and feature integration. Several methods of moving fluids into and within microfluidic devices are described, including batch‐flow and continuous‐flow micropumps, electrokinetic pumps, and external positive displacement pumps. Solutions for the problem of interfacing external fluid sources with a microfluidic device are given. Then, various methods for the construction of microfluidic devices are discussed, such as photolithography, soft lithography, and laminate‐based designs. Finally, as a case study, the integration of a microfluidic device for the detection of pathogens is described.
Thin layer extraction—A novel liquid–liquid extraction method
Authors: Lavie Ram
Published: February 2008

The overall task of a liquid–liquid extraction process consists of selectively transferring solutes from a donor solution to a recipient solution through a liquid extractant, with the purpose of purifying the donor solution and/or recovering a valuable solute. Thin layer extraction (TLX) is a novel method to carry out this task, using specialized equipment and temporal modes of operation. In TLX, a minute amount of an extractant that is firmly attached as thin layer to a solid substrate is intimately and frequently brought into contact alternately with the donor and recipient solutions. TLX incorporates the complete extraction/stripping scheme into one single device. Following presentation of the underlying concepts, the structural, design, and operational aspects are discussed. TLX is applicable on a wide range of scales and can be easily scaled up to production floor size or down to the microscale. It has inherent operational, safety, and environmental qualities. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Gas transfer and liquid dispersion inside a deep airlift reactor
Authors: Giovannettone J. P. , Gulliver J. S.
Published: February 2008

Gas transfer experiments in bubbly flow are conducted inside a deep bubble column/airlift reactor containing air and water with a maximum aerated water height of 23.4 m and diameter of 1.06 m. The effects of geometry and operating conditions on mixing and gas transfer are determined. Fluorescence measurements are used to estimate dispersion coefficients for several operating conditions, while bubble‐water gas transfer measurements are made using dissolved oxygen (DO) probes. A two‐phase convection‐dispersion model is fit to the DO measurements using the liquid film coefficient (kL) as a fitting parameter. Sparger differences had a substantial effect upon kL, and the gas transfer coefficient for the airlift reactor was four times that of the bubble column. Results are characterized using Sherwood, Reynolds, and Bond numbers. A low Reynolds number exponent was found, indicating that kL in a deep column tends toward a constant and is not highly dependent upon air discharge. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Group size and composition influence male and female reproductive success in black howler monkeys (Alouatta pigra)
Authors: Van Belle Sarie , Estrada Alejandro
Published: February 2008

It has been argued that grouping patterns might influence the reproductive performance of individuals. Increasing group size results in greater travel costs and competition over depletable food resources, which could lead to reduced individual reproductive success. However, in groups with an increasing number of males, female reproductive success is predicted to augment because larger male groups might better protect immatures from infanticidal attacks. In contrast, male reproductive success is predicted to decrease with number of males in a group because fertilization cannot be shared between males. In this paper, we test these predictions on the Mesoamerican black howler monkey (Alouatta pigra) with data on group size and composition for 120 groups from eight populations of black howler monkeys existing in eight protected forests in Mexico and Guatemala. Male and female reproductive success were calculated as a deviation of the observed number of infants (or immatures) from the expected number of infants (or immatures), relative to the number of males and females in a group. Results indicate that both male and female reproductive success decreased with group size. Male reproductive success decreased with an increasing number of males in a group and with increasing proportion of males relative to females in a group. Decreased female reproductive success was associated with increasing number of females in a group, and female reproductive success had a tendency to increase with increasing number of males in a group. These results suggest that in black howler monkeys, living in larger groups might negatively affect the reproductive success of each member. Our findings are similar to those reported for a population of a sister species,Alouatta palliata, living in larger groups. Am. J. Primatol. 70:613–619, 2008. © 2008 Wiley‐Liss, Inc.
Polyamide‐enhanced flame retardancy of ammonium polyphosphate on epoxy resin
Authors: Wang Jun‐Sheng , Wang De‐Yi , Liu Yun , Ge Xin‐Guo , Wang Yu‐Zhong
Published: February 2008

An attractive intumescent flame retardant epoxy system was prepared from epoxy resin (diglycidyl ether of bisphenol A), low molecular weight polyamide (cure agent, LWPA), and ammonium polyphosphate (APP). The cured epoxy resin was served as carbonization agent as well as blowing agent itself in the intumescent flame retardant formulation. Flammability and thermal stability of the cured epoxy resins with different contents of APP and LWPA were investigated by limited oxygen index (LOI), UL‐94 test, and thermogravimetric analysis (TGA). The results of LOI and UL‐94 indicate that APP can improve the flame retardancy of LWPA‐cured epoxy resins. Only 5 wt % of APP can increase the LOI value of epoxy resins from 19.6 to 27.1, and improve the UL‐94 ratings, reaching V‐0 rating from no rating when the mass ratio of epoxy resin to LWPA is 100/40. It is much interesting that LOI values of flame retardant cured epoxy resins (FR‐CEP) increase with decreasing LWPA. The results of TGA, FTIR, and X‐ray photoelectron spectroscopy (XPS) indicate that the process of thermal degradation of FR‐CEP consists of two main stages: the first stage is that a phosphorus rich char is formed on the surface of the material under 500°C, and then a compact char yields over 500°C; the second stage is that the char residue layer can give more effective protection for the materials than the char formed at the first stage do. The flame retardant mechanism also has been discussed according to the results of TGA, FTIR, and XPS for FR‐CEP. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal and mechanical properties of blended polyimide and amine‐functionalized poly(orthosiloxane) composites
Authors: Iyer Pallavi , Coleman Maria R.
Published: February 2008

Nanocomposite films were prepared through the blending of polyimide (PI) with octaphenyl silsesquioxane (OPS) and an amino‐functionalized analogue, octaaminophenyl silsesquioxane (OAPS), with a solution‐casting method. Although the PI–OPS composites showed visible phase separation at 5 wt %, the PI–OAPS composites were transparent with visible phase separation occurring only at 50 wt % OAPS. The interfacial interactions and homogeneity of the composites were characterized with scanning electron microscopy (SEM) and dynamic mechanical analysis. SEM analysis showed a uniform fracture surface for OAPS composites at concentrations up to 20 wt %. Interestingly, OAPS‐rich particles with sizes of less than 1 μm were formed within the PI matrix for the 50 wt % composite. The PI–OAPS composites showed higher glass‐transition temperatures (Tg's) than the pure PI. The PI–OPS composites showed a Tg lower than that of the pure PI, and this suggested poor interfacial interactions. The slightly enhanced thermal stability of PI–OAPS composites (up to 20 wt %) was attributed to the inherent thermal stability of OAPS at higher temperatures. There were small increases in the modulus and strength for the composites with respect to the base polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Study of the behavior of polyester concretes containing ionomers as curing agents
Authors: Ignacio Carlos , Ferraz Vany , Oréfice Rodrigo L.
Published: February 2008

Polyester concretes have been used in constructions for more than 20 years. This type of polymer concrete can advantageously replace traditional Portland concrete in situations that require fast consolidation of the material. Otherwise, polyester concretes are usually more expensive than Portland concretes. Part of the high cost of the polyester concretes is due to the fact that the aggregates used in the formulation of the concretes need to be dried prior to their incorporation into the polymer matrix. In this work, the use of different curing systems (methacrylic acid and maleic anhydride) was investigated to test the hypothesis that the introduction of acid functionalities into unsaturated polyesters based on isophthalic acid could both restrict the detrimental effect of moisture in the curing process and also improve interfacial interactions even in polyester concretes containing wet aggregates. In this work, as there was no search for ways to reduce cost of polyester concretes and also to contribute to the environmental preservation, unsaturated polyesters were synthesized from PET bottles and tested in the fabrication of concretes by reacting them with a conventional curing agent (styrene). Gel permeation chromatography, infrared spectroscopy, and electron microscopy were used to monitor and analyze the production of unsaturated polyester resins and concretes. Mechanical properties were also evaluated by compression tests. Results showed that methacrylic acid and maleic anhydride, when used as curing agents, led to the production of polyester concretes having higher mechanical properties in both dry and wet states than conventional polyester (based on isophthalic acid) concretes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Rheological characterization of carbon black/polystyrene solution systems
Authors: Aoki Yuji
Published: February 2008

Steady‐shear measurements of suspensions of carbon blacks (CB) in polystyrene (PS)/di‐(butyl phthalate) (DBP) solution were investigated as a function of volume fraction (ϕ) of CB to clarify the effect of the primary particle size and the structure of CB aggregates on the rheological properties. The suspensions show a typical shear‐thinning behavior in the range of a shear rate studied. The Casson model was applied to evaluate the viscosity at infinite of shear rate η∞ and the yield stress σy for the suspensions. Relative viscosity η∞/ηm, (ηm: medium viscosity) thus obtained was compared to the high‐frequency viscosity for the ideal hard‐sphere silica suspensions to evaluate the effective volume fraction ϕeff of CB aggregates. The ϕeff value was larger for the higher‐structure CB with higher DBP absorption value, irrespective of the primary particle size. The yield stress σy had almost the same ϕeff dependence for neutral furnace CB/(PS/DBP) suspensions, although it was larger for acetylene black (AcB)/(PS/DBP) suspensions. These results demonstrated that the effective volume fraction is the most important quantity to characterize the CB aggregates on the rheological properties. It was also found that the correction of the medium viscosity changes due to polymer adsorption on the CB surface is important since neutral furnace CB adsorbs PS polymers but AcB hardly adsorbs PS polymers in the solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and mechanical properties of poly(vinyl chloride)/bamboo flour composites with a novel block copolymer as a coupling agent
Authors: Kim Jeong‐Yeol , Peck Jong Hyeon , Hwang Seok‐Ho , Hong Juseok , Hong Sung Chul , Huh Wansoo , Lee Sang‐Won
Published: February 2008

To improve the interfacial adhesion between poly(vinyl chloride) (PVC) and bamboo flour in PVC/bamboo flour composites, a novel coupling agent, poly(styrene‐co‐maleic anhydride)‐block‐poly(styrene‐co‐acrylonitrile) {P[(SMA)‐b‐(SAN)]}, was synthesized through living free‐radical polymerization in a one‐pot reaction. P[(SMA)‐b‐(SAN)] was synthesized by a nitroxide‐mediated polymerization technique in the presence of 2,2,6,6‐tetramethylpiperidin‐l‐oxyl with azobisisobutyronitrile. The conversion of maleic anhydride (>99%) and styrene (>65%) was relatively high and yielded P[(SMA)‐b‐(SAN)] with a narrow molecular weight distribution (weight‐average molecular weight/number‐average molecular weight <1.38). PVC was blended with bamboo flours in the presence of the synthesized coupling agent with a two‐roll mill. P[(SMA)‐b‐(SAN)] was added to the PVC matrix at a concentration of 55 or 20 wt %. As the content of P[(SMA)‐b‐(SAN)] in the wood–polymer composite increased, improved morphological and mechanical behaviors were observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays
Authors: Chen Ruyi , Peng Fubing , Su Shengpei
Published: February 2008

The oligomeric poly(styrene‐acrylamide‐vinylbenzylchloride) (P(St‐AM‐VBC)) quaternary ammonium salts have been prepared from the reactions of trimethylamine with the corresponding P(St‐AM‐VBC)s, which were synthesized by free‐radical polymerization of a mixture of styrene, acrylamide, and vinylbenzylchloride. Then the swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays have been prepared through cation exchange of the sodium ions in the clay with the corresponding P(St‐AM‐VBC) quaternary ammonium salts. The P(St‐AM‐VBC) and its modified clays have been characterized by infrared spectra (IR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H NMR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The solvent‐swelling capacity of poly(styrene‐co‐acrylamide) modified clays have also been tested, and the experimental results have indicated that these clays are novel swelling tunable organic clays. XRD and TEM studies have shown that these novel swelling tunable clays are well‐intercalated or exfoliated. Furthermore, TGA analysis shows that these polymerically modified clays have high thermal stability for nanocomposites by melt blending. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Information science during the first decade of the web: An enriched author cocitation analysis
Authors: Zhao Dangzhi , Strotmann Andreas
Published: February 2008

Using an enriched author cocitation analysis (ACA), we map information science (IS) for 1996–2005, a decade of explosive development of the World Wide Web, to examine its development since the landmark study by White and McCain (1998). The Web, we find, has had a profound impact on IS, driving the creation of new disciplines and revitalization or obsolescence of old, and most importantly, bridging the chasm between the “literatures” and “retrieval” IS camps. Simultaneously, the development of IS towards cognitive aspects has intensified. Our study enriches classic ACA in that it employs both orthogonal and oblique rotations in the factor analysis (FA), and reports both pattern and structure matrices for the latter, thus enabling a comparison between these several FA methods in ACA. Each method provides interesting information not available from the others, we find, especially when results are also visualized in the novel manner we introduce here.
Modular transporters for subcellular cell‐specific targeting of anti‐tumor drugs
Authors: Sobolev Alexander S.
Published: February 2008

A major problem in the treatment of cancer is the specific targeting of anti‐tumor drugs to these abnormal cells. Ideally, such a drug should act over short distances to minimize damage to healthy cells, and target subcellular compartments that have the highest sensitivity to the drug. Photosensitizers, alpha‐emitting radionuclides and many other medicines could be considered as such drugs if they possessed cellular and subcellular specificity. The author describes a novel approach of using modular recombinant transporters to target photosensitizers and alpha‐emitting radionuclides to the nucleus, where their action is most pronounced, of cancer cells. Photosensitizer‐transporter conjugates have up to 3000 times greater efficacy than free photosensitizers and display cell specificity in contrast to free photosensitizers. Alpha‐emitting radionuclides, conjugated with the modular transporters, acquired similar properties. The different modules of the transporters are interchangeable, meaning that they can be tailored for particular applications. BioEssays 30:278–287, 2008. © 2008 Wiley Periodicals, Inc.
Epithelial topology
Authors: Nagpal Radhika , Patel Ankit , Gibson Matthew C.
Published: February 2008

It is universally accepted that genetic control over basic aspects of cell and molecular biology is the primary organizing principle in development and homeostasis of living systems. However, instances do exist where important aspects of biological order arise without explicit genetic instruction, emerging instead from simple physical principles, stochastic processes, or the complex self‐organizing interaction between random and seemingly unrelated parts. Being mostly resistant to direct genetic dissection, the analysis of such emergent processes falls into a grey area between mathematics, physics and molecular cell biology and therefore remains very poorly understood. We recently proposed a mathematical model predicting the emergence of a specific non‐Gaussian distribution of polygonal cell shapes from the stochastic cell division process in epithelial cell sheets; this cell shape distribution appears to be conserved across a diverse set of animals and plants.1 The use of such topological models to study the process of cellular morphogenesis has a long history, starting almost a century ago, and many insights from those original works influence current experimental studies. Here we review current and past literature on this topic while exploring some new ideas on the origins and implications of topological order in proliferating epithelia. BioEssays 30:260–266, 2008. © 2008 Wiley Periodicals, Inc.
A new role of the rDNA and nucleolus in the nucleus—rDNA instability maintains genome integrity
Authors: Kobayashi Takehiko
Published: February 2008

The nucleolus is a region of the nucleus with high protein density and it acts as a ribosome factory. The nucleolus contains a distinct region of the genome, the ribosomal RNA gene repeats (rDNA) that supply ribosomal RNA (rRNA) molecules. The rDNA is the most‐abundant gene and occupies a large part of the genome, for example, there are thousands of rDNA copies in the genomes of plant cells. Therefore, it is natural to suppose that the condition of the rDNA, such as its stability, might affect cellular functions. Here I would like to propose a new model regarding the roles of the rDNA and nucleolus. The key point of this model is that they act to preserve genome stability and trigger aging. BioEssays 30:267–272, 2008. © 2008 Wiley Periodicals, Inc.
Losing B cell identity
Authors: Carotta Sebastian , Nutt Stephen L.
Published: February 2008

The transcription factor Pax5 is essential for the initial commitment of hematopoietic progenitors to the B cell lineage. Recently, our understanding of the lineage commitment process has been extended with the finding that Pax5 is also continuously required throughout B cell development to reinforce commitment, as inactivation of Pax5 in mature B cells results in their de‐differentiation to a progenitor stage that is capable of multi‐lineage potential.1 The reliance of B cell identity on a single gene is not without its problems as the loss of Pax5 results in B cell malignancies in mouse models and mutation in human PAX5 is the most‐common genetic lesion in acute lymphoblastic leukemia. BioEssays 30:203–207, 2008. © 2008 Wiley Periodicals, Inc.
Assessment of cell engineering strategies for improved therapeutic protein production in CHO cells
Authors: Mohan Chaya , Kim Yeon‐Gu , Koo Jane , Lee Gyun Min
Published: February 2008

Recombinant glycoprotein therapeutics have proven to be invaluable pharmaceuticals for the treatment of various diseases. Chinese hamster ovary (CHO) cells are widely used in industry for the production of these proteins. Several strategies for engineering CHO cells for improved protein production have been tried with considerable results. The focus has mainly been to increase the specific productivity and to extend the culture longevity by preventing programmed cell death. These CHO cell engineering strategies, particularly those developed in Korea, are reviewed here.
The prognostic value of combined intracoronary pressure and blood flow velocity measurements after deferral of percutaneous coronary intervention
Authors: Meuwissen Martijn , Chamuleau Steven A.J. , Siebes Maria , de Winter Robbert J. , Koch Karel T. , Dijksman Lea M. , van den Berg Anja J. , Tijssen Jan G.P. , Spaan Jos A.E. , Piek Jan J.
Published: February 2008

Objectives: We evaluated deferral of PCI of intermediate coronary lesions (IL) using fractional (FFR) and coronary flow reserve (CFR) hyperemic stenosis resistance index (HSR) in patients with a negative or nondiagnostic and noninvasive stress tests. Background: Outcome after deferral of PCI of IL with discordant results between FFR and CFR is unknown. Methods: PCI was deferred in 186 IL (mean diameter stenosis: 52%). Patients were divided according to the results of FFR and CFR in group A; FFR ≥ 0.75 and CFR ≥ 2.0 (n = 129), group B; FFR ≥ 0.75 and CFR 2.0 (n = 28), group C; FFR 0.75 and CFR ≥ 2.0 (n = 23) and group D; FFR 0.75 and CFR 2.0 (n = 6). Patients were followed for one year to document major adverse cardiac events (MACE). Results: Nineteen MACEs (0 deaths, 4 myocardial infarctions, 1 CABG, and 14 PCIs) occurred during a follow up of 323 ± 88 days. MACE rate was lowest (4.7%) when FFR, CFR, and HSR were normal. A higher MACE rate was observed when concordant abnormal (group D) or discordant results between FFR and CFR (group B and C) were compared to concordant normal values (group A, 33.3% vs. 19.7% vs. 5.4%, P = 0.008). Multivariate regression analysis showed a higher predictive power for HSR than for FFR and CFR. Conclusions: Abnormal FFR or abnormal CFR was documented in 31% of intermediate coronary lesions. Deferral of PCI in this group was associated with a high MACE rate, which underscores the rationale of combined pressure and flow measurements providing a stenosis resistance index that is better suited for clinical decision making in these lesions. © 2008 Wiley‐Liss, Inc.
Transient left ventricular apical ballooning: A unifying pathophysiologic theory at the edge of Prinzmetal angina
Authors: Angelini Paolo
Published: February 2008

Introduction:

Takotsubo or ampulla transient left ventricular apical ballooning (LVAB) cardiomyopathy has been described as a clinical syndrome characterized by the sudden onset of chest pain, cardiac failure, ischemic changes on electrocardiography, and apical severe myocardial dysfunction in the presence of “normal” coronary arteries on angiography. All features last from a few days to a few weeks.

Methods and Results:

On the basis of previous knowledge and in light of our recent experience with acetylcholine testing in this condition, the cases of four patients are described and preliminary but sound arguments are given to support the theory that LVAB is caused by severe, sustained spasm of many or all of the coronary vessels. In one of these patients, experimental reproduction of LVAB occurred in the catheterization laboratory during acetylcholine testing (as evidenced by echocardiographic monitoring), while in two other patients, the test provoked similar, extensive angiographic vasospasm and suggestive symptoms. In addition, the similarities and differences that exist between LVAB and Prinzmetal angina are discussed.

Conclusion:

To evaluate the pathogenesis of LVAB, it is proposed that acetylcholine testing be routinely performed under specific, prospective, investigational protocols at specialized centers. © 2008 Wiley‐Liss, Inc.
Prognostic value of troponin after elective percutaneous coronary intervention: A meta‐analysis
Authors: Nienhuis Mark B. , Ottervanger Jan Paul , Bilo Henk J.G. , Dikkeschei Bert D. , Zijlstra Felix
Published: February 2008

Background: Although the prognostic importance of troponin in patients with anacute coronary syndrome is clear, the significance of troponin elevation after elective percutaneous coronary intervention (PCI) is a subject of debate. However, most studies up to now had a small sample size and insufficient events during follow‐up. Methods: Electronic and manual searches were performed of studies reporting on prognosis of troponin after elective PCI. A meta‐analysis was done of all suitable studies, with death in follow‐up as primary endpoint and the combination of death or nonfatal myocardial infarction in follow‐up as secondary endpoint. Results: 20 studies involving 15,581 patients were included. These studies were published between 1998 and 2007. Overall, troponin was elevated after elective PCI in 32.9% of patients. The follow‐up period varied between 3 and 67 months (mean 16.3). Increased mortality was significantly associated with troponin elevation after PCI (4.4% vs. 3.3%, P = 0.001; OR 1.35). Furthermore, the combined endpoint of mortality or nonfatal myocardial infarction also occurred more often in patients with post‐procedural troponin elevation (8.1% vs. 5.2%, P < 0.001; OR 1.59). Conclusions: According to this meta‐analysis, troponin elevation after elective PCI provides important prognostic information. © 2008 Wiley‐Liss, Inc.
Stenting complex aortic arch obstructions
Authors: Holzer Ralf J. , Chisolm Joanne L. , Hill Sharon L. , Cheatham John P.
Published: February 2008

Objective:

To present our institutional experience of endovascular stent therapy in patients with complex aortic arch lesions.

Background:

The management of aortic arch obstructions is complex and many physicians are either reluctant to treat mild–moderate aortic arch lesions associated with systemic hypertension or instead refer to high‐risk surgical alternatives. Reported data on transcatheter stent therapy of complex aortic arch lesions are scarce.

Methods:

Between October 2002 and November 2006, 40patients (pts) had complex aortic arch lesions treated with stent implantation in 42 procedures (proc). Aortic arch hypoplasia was present in 30/42 proc (71.4%). The median age was 10 year (16 days ‐ 37 years). In 40/42 proc (95.2%) patients had previous transcatheter or surgical aortic arch interventions.

Results:

Procedural success in achieving a peak systolic gradient reduction to ≤10 mm Hg with an improvement in the diameter to ≥90% of the “normal” adjacent aortic arch was achieved in 38/42 proc (90.5%). The diameter of the arch obstruction increased from a median of 7.55 mm to a median of 14 mm (P < 0.0001) and the peak systolic gradient was reduced from a median of 23 mm Hg to a median of 2 mm Hg (P < 0.0001). Arch vessels were crossed in 31/42 proc (73.8%). Periprocedural adverse events were encountered in 13/42 proc (30.9%), predominately in patients with a weight below 10 kg or univentricular physiology. The median follow‐up was 1 year (32 days ‐ 3.8 years). The incidence of systemic hypertension was significantly reduced from 22/42 (52.4%) before the procedure to 6/39 (15.4%) at the most recent follow‐up (P = 0.0005). CT or MRI evaluations were performed in 18 pts, documenting all crossed arch vessels to appear patent.

Conclusions:

Stenting of complex aortic arch lesions can be performed safely and effectively with excellent, immediate, and midterm results. Patients with a weight below 10 kg or after Hybrid stage I palliation are at increased risk of adverse events. Stents can be placed across major arch vessels without compromising distal perfusion in otherwise normal vasculature. © 2008 Wiley‐Liss, Inc.
Relation of corrected thrombolysis in myocardial infarction frame count and ST‐segment resolution to myocardial tissue perfusion after acute myocardial infarction
Authors: Li Chun‐Mei , Zhang Xing‐Hua , Ma Xiao‐Jing , Zhu Xing‐Lei
Published: February 2008

Objectives: To evaluate myocardial tissue perfusion by corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and ST‐segment resolution after successful percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Background: Early and sustained potency of infarct‐related artery (IRA) has become the main goal of reperfusion therapy in patients with AMI. However, myocardial tissue perfusion may remain impaired even after the achievement of TIMI grade 3 flow of the epicardial artery without residual stenosis. Methods: CTFC was measured after successful PCI in 63 patients with first AMI. The extent of ST‐segment resolution was recorded 1 hr after reperfusion therapy. The wall motion score index (WMSI) was assessed before and 1 month after PCI. Then we studied the correlation between CTFC, ST‐segment resolution, and WMSI. Results: According to CTFC, the patients with TIMI grade 3 flow after PCI were divided into two groups: CTFC fast group and CTFC slow group. CTFC fast group had higher percentage of complete ST resolution (54.1% vs. 25.0%, P < 0.05) and lower percentage of no ST resolution (2.6% vs. 29.2%, P < 0.05). Improvement of WMSI in the CTFC fast group was significantly greater than that of the CTFC slow group (1.30 ± 0.41 vs. 0.64 ± 0.30, P < 0.05). CTFC had a significant negative correlation with the change in WMSI (r = −0.75, P < 0.01). Conclusions: Combined with ST‐segment resolution, CTFC could predict risk for patients with successful reperfusion therapy after AMI and provide evidence for additional adjunctive treatment. © 2008 Wiley‐Liss, Inc.
A new ostial stent positioning system (Ostial Pro™) for the accurate placement of stents to treat aorto‐ostial lesions
Authors: Fischell Tim A. , Malhotra Surender , Khan Shakeel
Published: February 2008

Background:

The stenting of aorto‐ostial lesions in the native coronary circulation, renal arteries, and saphenous vein grafts is technically challenging.

Methods:

We report the first in the world use of the Ostial Pro™, a novel nitinol‐based device, utilized in conjunction with standard stenting techniques to assist in the precise placement of stents for the treatment of aorto‐ostial lesions.

Results:

The Ostial Pro, is a relatively simple nitinol device that is positioned within the guiding catheter. It has distal, self‐expanding legs that are advanced just distal to the tip of the guiding catheter after the ostial lesion has been crossed with the coronary guidewire and stent delivery system. The expanded nitinol legs prevent the entry of the guiding catheter into the target vessel, mark the plane of the aortic wall, and align the tip of the guide with the aorto‐ostial plane. We report the successful and precise placement of stents in the aorto‐ostial location in two patients with; (1) a saphenous vein graft ostial lesion and (2) a right coronary ostial lesion, using the new Ostial Pro stent positioning device. Excellent stent positioning, relative to the aorto‐ostial plane, was confirmed by angiography and long axis intravascular ultrasound in both cases.

Conslusions:

(1) The Ostial Pro is a new, commercially available (FDA cleared), nitinol device that is simple to use and appears effective in allowing the precise placement of stent(s) at the aorto‐ostial location. (2) This approach may provide a simple and effective means to assure accurate stent placement in these difficult to treat lesions. © 2008 Wiley‐Liss, Inc.
Linear Polynuclear Helicates as a Link between Discrete Supramolecular Complexes and Programmed Infinite Polymetallic Chains
Authors: Dalla‐Favera Natalia , Hamacek Josef , Borkovec Michal , Jeannerat Damien , Gumy Frédéric , Bünzli Jean‐Claude G. , Ercolani Gianfranco , Piguet Claude
Published: February 2008

The contribution of the solvation energies to the assembly of polynuclear helicates reduces the free energy of intermetallic repulsion, ΔEMM, in condensed phase to such an extent that stable D3‐symmetrical tetranuclear lanthanide‐containing triple‐stranded helicates [Ln4(L4)3]12+ are quantitatively produced at millimolar concentrations, despite the twelve positive charge borne by these complexes. A detailed modelling of the formation constants using statistical factors, adapted to self‐assembly processes involving intra‐ and intermolecular connections, provides a set of five microscopic parameters, which can be successfully used for rationalizing the stepwise generation of linear bi‐, tri‐ and tetranuclear analogues. Photophysical studies of [Eu4(L4)3]12+ confirm the existence of two different binding sites producing differentiated metal‐centred emission at low temperature, which transforms into single site luminescence at room temperature because of intramolecular energy funelling processes.
Supramolecular Assemblies of Tripodal Porphyrin Hosts and C60
Authors: Tong Lok H. , Wietor Jean‐Luc , Clegg William , Raithby Paul R. , Pascu Sofia I. , Sanders Jeremy K. M.
Published: February 2008

The self‐assembly of two tripodal porphyrin hosts in the presence of C60, in the solid state, has been studied using synchrotron X‐ray crystallography, and in solution by using1H NMR and fluorescence spectroscopies. The binding affinities, stoichiometries and geometries strongly depend on the size of the porphyrin host. Intramolecular and/or intermolecular porphyrin–fullerene interactions are observed in the co‐crystallites and in each case, the trimer exhibits a “tweezers‐like” structural motif. The solid‐state structures of the trimer‐fullerene co‐crystallites reveal close fullerene–porphyrin and fullerene–fullerene contacts.
Self‐Assembled Structures in Organogels of Amphiphilic Diblock Codendrimers
Authors: Yang Miao , Zhang Zijian , Yuan Fei , Wang Wei , Hess Sandra , Lienkamp Karen , Lieberwirth Ingo , Wegner Gerhard
Published: February 2008

Amphiphilic diblock codendrimers consisting of dendrons of hydroxyl‐containing poly(methallyl dichloride) (PMDC) and long alkyl‐containing poly(urethane amide) (PUA) were synthesized in different generations. These codendrimers were found to self‐assemble into ribbonlike aggregates in organic solvent and further formed three‐dimensional networks and behaved macroscopically as gels. The width of the self‐assembled ribbons decreases with the generation of both dendritic blocks. Multiple intermolecular hydrogen bonds between amide and hydroxyl groups were found to be the main driving force to form these self‐assembled gels.
Towards high‐throughput single cell/clone cultivation and analysis
Authors: Lindström Sara , Larsson Rolf , Andersson Svahn Helene
Published: February 2008

In order to better understand cellular processes and behavior, a controlled way of studying high numbers of single cells and their clone formation is greatly needed. Numerous ways of ordering single cells into arrays have previously been described, but platforms in which each cell/clone can be addressed to an exact position in the microplate, cultivated for weeks and treated separately in a high‐throughput manner have until now been missing. Here, a novel microplate developed for high‐throughput single cell/clone cultivation and analysis is presented. Rapid single cell seeding into microwells, using conventional flow cytometry, allows several thousands of single cells to be cultivated, short‐term (72 h) or long‐term (10–14 days), and analyzed individually. By controlled sorting of individual cells to predefined locations in the microplate, analysis of single cell heterogeneity and clonogenic properties related to drug sensitivity can be accomplished. Additionally, the platform requires remarkably low number of cells, a major advantage when screening limited amounts of patient cell samples. By seeding single cells into the microplate it is possible to analyze the cells for over 14 generations, ending up with more than 10 000 cells in each well. Described here is a proof‐of‐concept on compartmentalization and cultivation of thousands of individual cells enabling heterogeneity analysis of various cells/clones and their response to different drugs.
Prolyl endopeptidase is revealed following SILAC analysis to be a novel mediator of human microglial and THP‐1 cell neurotoxicity
Authors: Klegeris Andis , Li Jane , Bammler Theo K. , Jin Jinghua , Zhu David , Kashima Daniel T. , Pan Sheng , Hashioka Sadayuki , Maguire John , Mcgeer Patrick L. , ZHANG JING
Published: February 2008

Reactive microglial cells may exacerbate the pathology in some neurodegenerative disorders. Supernatants of stimulated human microglial cells, or their surrogate THP‐1 cells, are lethal to cultured human neuroblastoma SH‐SY5Y cells. To explore this neurotoxicity, we examined the spectrum of proteins generated by THP‐1 cells using the technique of stable isotope labeling by amino acids in cell culture (SILAC). Unstimulated cells were grown in medium with light L‐[12C6] arginine while cells stimulated by lipopolysaccharide (LPS) plus interferon‐γ (IFN‐γ) were grown in medium with heavy L‐[13C6] arginine. Proteins isolated from the media were digested with trypsin, and relative concentrations of generated peptides determined by mass spectrometry. More than 1,500 proteins or putative proteins were identified. Of these, 174 were increased and 189 decreased by more than twofold in the stimulated cell supernatant. We selected one upregulated protein, prolyl endopeptidase (PEP), for further investigation of its potential contribution to neurotoxicity. We first confirmed its upregulation by comparing its enzymatic activity in stimulated and unstimulated cell supernatants. We then evaluated two specific PEP inhibitors, Boc‐Asn‐Phe‐Pro‐aldehyde and Z‐Pro‐Pro‐aldehyde‐dimethyl acetal, for their potential to reduce toxicity of stimulated THP‐1 cell and human microglia supernatants towards SH‐SY5Y cells. We found both to be partially protective in a concentration‐dependent manner. Inhibition of PEP may be a therapeutic approach to neurodegenerative disorders including Alzheimer and Parkinson diseases. © 2008 Wiley‐Liss, Inc.
Calcium/calcineurin signaling in primary cortical astrocyte cultures: Rcan1‐4 and cyclooxygenase‐2 as NFAT target genes
Authors: Canellada Andrea , Ramirez Belén G. , Minami Takashi , Redondo Juan Miguel , Cano Eva
Published: February 2008

The calcineurin/nuclear factor of activated T cells (NFAT) signaling pathway mediates important cell responses to calcium, but its activity and function in astrocytes have remained unclear. We show that primary cortical astrocyte cultures express the regulatory and catalytic subunits of the phosphatase calcineurin as well as the calcium‐regulated NFAT family members (NFATc1, c2, c3, and c4). NFATs are activated by calcium‐mobilizing agents in astrocytes, and this activation is blocked by the calcineurin inhibitor cyclosporine A. Microarray screening identified cyclooxygenase‐2 (Cox‐2), which is implicated in brain injury, and Rcan 1‐4, an endogenous calcineurin inhibitor, as genes up‐regulated by calcineurin‐dependent calcium signals in astrocytes. Mobilization of intracellular calcium with ionophore potently augments the promoter activity and mRNA and protein expression of Rcan 1‐4 and Cox‐2 induced by combined treatment with phorbol esters. Moreover, Rcan 1‐4 expression is efficiently induced by calcium mobilization alone. For both the genes, the calcium signal component is dependent on calcineurin and is replicated by exogenous expression of a constitutively active NFAT, strongly suggesting that the calcium‐induced gene activation is mediated by NFATs. Finally, we report that calcineurin‐dependent expression of Cox‐2 and Rcan 1‐4 is induced by physiological calcium mobilizing agents, such as thrombin, agonists of purinergic and glutamate receptors, and L‐type voltage‐gated calcium channels. These findings provide insights into calcium‐initiated gene transcription in astrocytes, and have implications for the regulation of calcium responses in astrocytes. © 2008 Wiley‐Liss, Inc.
Mechanisms of ATP‐ and glutamate‐mediated calcium signaling in white matter astrocytes
Authors: Hamilton Nicola , Vayro Steven , Kirchhoff Frank , Verkhratsky Alexej , Robbins Jon , Gorecki Dariuz C. , Butt Arthur M.
Published: February 2008

Neurotransmitters released at synapses mediate Ca2+ signaling in astrocytes in CNS grey matter. Here, we show that ATP and glutamate evoke these Ca2+ signals in white matter astrocytes of the mouse optic nerve, a tract that contains neither neuronal cell bodies nor synapses. We further demonstrate that action potentials along white matter axons trigger the release of ATP and the intercellular propagation of astroglial Ca2+ signals. These mechanisms were studied in astrocytes in intact optic nerves isolated from transgenic mice expressing enhanced green fluorescent protein (EGFP) under control of the human glial fibrillary acidic protein promoter (GFAP) by Fura‐2 ratiometric Ca2+ imaging. ATP evoked astroglial Ca2+ signals predominantly via metabotropic P2Y1 and ionotropic P2X7 purinoceptors. Glutamate acted on both AMPA‐ and NMDA‐type receptors, as well as on group I mGlu receptors to induce an increase in astroglial [Ca2+]i. The direct Ca2+ signal evoked by glutamate was small, and the main action of glutamate was to trigger the release of the “gliotransmitter” ATP by a mechanism involving P2X7 receptors; propagation of the glutamate‐mediated Ca2+ signal was significantly reduced in P2X7 knock‐out mice. Furthermore, axonal action potentials and mechanical stimulation of astrocytes both induced the release of ATP, to propagate Ca2+ signals in astrocytes and neighboring EGFP‐negative glia. Our data provide a model of multiphase axon–glial signaling in the optic nerve as follows: action potentials trigger axonal release of ATP, which evokes further release of ATP from astrocytes, and this acts by amplifying the initiating signal and by transmitting an intercellular Ca2+ wave to neighboring glia. © 2008 Wiley‐Liss, Inc.
Astrocytes, but not olfactory ensheathing cells or Schwann cells, promote myelination of CNS axons in vitro
Authors: Sorensen Annette , Moffat Keith , Thomson Christine , Barnett Susan C.
Published: February 2008

We have examined the interaction between olfactory ensheathing cells (OECs), Schwann cells (SC), oligodendrocytes, and CNS axons using cultures generated from embryonic rat spinal cord. Oligodendrocyte process extension and myelination in these cultures was poor if the cells were plated on OECs or SCs. Myelin internodes and nodes of Ranvier formed frequently if these cultures were plated onto monolayers of neurosphere‐derived astrocytes (NsAs). In the myelinated fibers generated on NsAs, Nav channels, caspr, and neurofascin molecules were correctly assembled at the nodes of Ranvier. The density of neurites, survival, and antigenic differentiation of oligodendrocytes was similar on OEC and NsAs monolayers. However, on OEC monolayers, despite a transient increase in the number of endogenous oligodendrocytes, there was a decrease in oligodendrocyte process extension and axonal ensheathment when compared with cultures plated on NsAs monolayers. To determine if these changes were due to axonal or glial factors, spinal cord oligodendrocytes were plated onto monolayers of OECs, NsAs, and poly‐L‐lysine in the absence of neurons. In these cultures, process extension and myelin‐like membrane formation by oligodendrocytes was improved on monolayers of OEC. This suggests that inhibition of process extension is mediated via cross‐talk between OECs and neurites. In cultures containing axons plated on OEC monolayers, oligodendrocyte process formation, axonal ensheathment, and myelination occurred albeit lower if the cultures were supplemented with NsAs conditioned medium. These data suggest OECs can permit neurite extension and oligodendrocyte proliferation, but lack secreted factor(s) and possible cell–cell contact that is necessary for oligodendrocyte process extension and myelination. © 2008 Wiley‐Liss, Inc.
Autophagy activation by rapamycin eliminates mouse Mallory-Denk bodies and blocks their proteasome inhibitor-mediated formation
Authors: Harada Masaru , Hanada Shinichiro , Toivola Diana M. , Ghori Nafisa , Omary Bishr M.
Published: February 2008

The proteasomal and lysosomal/autophagy pathways in the liver and other tissues are involved in several biological processes including the degradation of misfolded proteins. Exposure of hepatocyte cell lines to proteasome inhibitors (PIs) results in the formation of inclusions that resemble Mallory-Denk bodies (MDBs). Keratins are essential for MDB formation and keratin 8 (K8)-overexpressing transgenic mice are predisposed to MDB formation. We tested the hypothesis that PIs induce MDBs in vivo and that autophagy participates in MDB turnover. The effect of the PI bortezomib (which is used to treat some malignancies) on MDB formation was tested in K8-overexpressing mice and in cultured cells. Inclusion formation was examined using immune and conventional electron microscopy (EM). Bortezomib induced MDB-like inclusions composed of keratins, ubiquitin, and p62 in cultured cells. Short-term exposure to bortezomib induced similar inclusions in K8-overexpressing but not in nontransgenic mice, without causing liver injury. In bortezomib-treated mice, autophagy was activated in hepatocytes as determined by EM and biochemical analysis. Further activation of autophagy by rapamycin (Rap) decreased the number of inclusions in bortezomib-treated K8 transgenic mice significantly. Rap also led to resorption of spontaneously formed MDBs in aging K8-overexpressing mice. Immune EM demonstrated K8-positive and ubiquitin-positive structures in autophagic vacuoles in the mouse liver.

Conclusion:

PIs alone are sufficient to induce MDBs in susceptible animals, while Rap-mediated activation of autophagy prevents MDB formation and causes MDB resorption. These findings suggest that some patients treated with PIs may become predisposed to MDB formation. Autophagy provides a potential cellular mechanism for the resorption of cytoplasmic inclusions.
Seasonal forecast of cooling water problems in the River Rhine
Authors: Rutten Martine , van de Giesen Nick , Baptist Martin , Icke Joost , Uijttewaal Wim
Published: February 2008

Cooling water scarcity in the River Rhine due to low flows during summer and high water temperatures may endanger power supply in the Netherlands and Germany. This research addresses the feasibility of early warning for cooling water problems on a seasonal timescale using large‐scale oceanic and atmospheric patterns as predictors. The correlation strength, stability as well as probabilistic skill of possible teleconnections were assessed. The strongest teleconnection was found between January North Atlantic Oscillation (NAO) and August water temperatures. The evaluated teleconnections between NAO and El Niño Southern Oscillation (ENSO) and discharge do not increase skill compared to only using information on discharge itself in the winter and spring months. In pseudo‐operational context model results were shown to be very sensitive to the choice of predictor selection criteria significance and stability. Though for some responses statistically significant forecasts were found, discussion and research with stakeholders about handling risk levels and probabilistic forecasts would be required to assess the practical significance of the forecasts. Copyright © 2008 John Wiley & Sons, Ltd.