bluuebunny/crossref_metadata_2025 huggingface dataset:
Structures and modulation algorithms of direct ac/ac converters with two legs and three legs for two‐phase systems
Authors: Kwak Sangshin
Published: January 2009

Two‐phase ac/ac matrix converter configurations are presented based on direct power conversion processes from three‐phase input ac supplies to two‐phase output ac loads. Two types of two‐phase matrix converter topologies, utilizing the standard matrix converter configuration, are introduced with two‐leg and three‐leg based structures. Pulse width modulation (PWM) strategies with high‐frequency composition for the two‐leg and the three‐leg based two‐phase matrix converters are developed to synthesize sinusoidal output waveforms of two‐phase loads from time‐varying input ac voltages. Grounded on the developed modulation algorithms, the presented matrix converters directly generate controllable two‐phase output voltages from sinusoidal input voltages with no intermediate dc conversion and concomittant dc‐link elements. The proposed matrix converters can provide sinusoidal output current/voltage waveforms with independently controlled magnitude and 90° phase angle to two‐phase loads. Thus, the converters are effective for both balanced and unbalanced two‐phase loads. The presented two‐phase operations with the standard matrix converter structures add the versatility for the matrix converter systems to function in multi‐phase loads as a universal converter. Simulation and experimental results are presented to verify the developed modulation techniques and the converter configurations for the two‐phase matrix converters. Copyright © 2009 John Wiley & Sons, Ltd.
A Half Cell Study of Performance and Degradation of Oxygen Reduction Catalysts for Application in Low Temperature Fuel Cells
Authors: Stassi A. , Modica E. , Antonucci V. , Aricò A. S.
Published: January 2009

An investigation of preleached PtCo/C catalysts for the oxygen reduction reaction (ORR) was carried out at 75 °C in sulphuric acid electrolyte by using a gas‐fed half‐cell in order to evaluate their stability characteristics. The influence of different leaching methods on catalyst stability was studied. Accelerated degradation tests were utilised to investigate the influence of platinum dissolution, sintering and carbon black corrosion. The catalysts behaviour was analysed in terms of performance loss before and after the electrochemical ageing. The PtCo catalyst preleached with perchloric acid showed a better stability than other catalysts in the specific Platinum degradation test; whereas, a significant degradation in the carbon corrosion test was observed for all catalysts.
Association between cognition and daily life functioning in dementia subtypes
Authors: Bouwens Sharon F. M. , van Heugten Caroline M. , Verhey Frans R. J.
Published: January 2009

Objective

To investigate the association between cognition and daily life functioning in dementia subtypes.

Methods

Cross‐sectional data were used from 615 patients with dementia who were referred to the Maastricht Memory Clinic of the Maastricht University Medical Centre. Pearson correlation coefficients were calculated between the Mini‐Mental State Examination (MMSE; to measure cognitive status) and the Blessed Dementia Scale (BDS; to measure daily life functioning) for the following types of dementia: Alzheimer's Disease (AD, n = 442); Vascular dementia (VaD, n = 113); frontotemporal dementia (FTD, n = 18); Parkinson's dementia (PD, n = 21); and primary progressive aphasia (PPA, n = 21). One‐way ANOVA was used to test differences in age, MMSE scores and BDS scores across dementia subtypes.

Results

Scores on the MMSE showed strong correlation with BDS scores in cases of FTD (r = −0.80); moderate correlation in cases of AD, VaD, and PD (range r = −0.50–0.60); while no correlation was found in PPA cases.

Conclusions

The association between cognition and daily life functioning varied among dementia subtypes for AD, VaD, FTD and PD. Furthermore, the overall scores on both domains differ between dementia subtypes, indicating that different types of dementia are characterized by a specific pattern of cognitive status and daily life functioning. These findings underline the need for multidomain assessment in patients with dementia. Copyright © 2009 John Wiley & Sons, Ltd.
Toxicity and survival outcomes of hyperfractionated split‐course reirradiation and daily concurrent chemotherapy in locoregionally recurrent, previously irradiated head and neck cancers
Authors: Watkins John M. , Shirai Keisuke S. , Wahlquist Amy E. , Stuart Robert K. , Chaudhary Uzair B. , Garrett‐Mayer Elizabeth , Day Terry A. , Gillespie M. Boyd , Sharma Anand K.
Published: January 2009

Background.

Reirradiation of locoregionally recurrent, previously irradiated head/neck cancer may be considered in situations of unresectability, medical inoperability, or adverse pathologic features found at salvage resection.

Methods.

Retrospective cohort analysis of toxicity and survival outcomes in locoregionally recurrent, previously irradiated patients with head/neck cancer treated with hyperfractionated split‐course radiotherapy and concurrent chemotherapy.

Results.

Between March 1998 and September 2006, 39 patients initiated reirradiation at median of 2.3 years (range, 0.5–19) following prior radiotherapy. At median survivor follow‐up of 24.5 months (range, 3–63.9), 10 patients are alive without evidence of disease. Median survival is 19.0 months, with estimated 1‐, 2‐, and 3‐year overall survivals of 60.1%, 45.1%, and 22.7%, respectively. Locoregional failure was the predominant site of postreirradiation recurrence. Male sex, total radiotherapy dose, cycles of chemotherapy completed, and clinical response were associated with improved overall survival.

Conclusions.

Reirradiation can offer long‐term survival for patients with recurrent, previously irradiated head/neck cancers. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
Role of chest CT in staging of oropharyngeal cancer: A systematic review
Authors: McLeod Niall M. H. , Jess Alex , Anand Rajiv , Tilley Elisabeth , Higgins Bernie , Brennan Peter A.
Published: January 2009

Background.

The prevalence of synchronous or metastatic tumors in patients with head and neck squamous cell carcinoma (HNSCC) ranges from 6% to 20% and has implications for prognosis and management of the primary disease. There is no consensus about the role of chest CT prior to definitive treatment patients with HNSCC.

Methods.

A systematic review of all chest CT studies in relation to HNSCC was performed, together with a review of our local database.

Results.

Twenty‐four studies were identified in addition to our local data. Prevalence of positive chest CT was 7.93%. Patients were significantly more likely to have a positive chest CT with N2 or N3 neck disease (p = .0062) and stage III or IV disease (p = .0001), and significantly less likely with tumors of the oral cavity (p = .0007).

Conclusion.

We advocate chest CT as part of the initial investigations for patients with HNSCC. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
Reduced excitability in the dentate gyrus network of βIV‐spectrin mutant mice in vivo
Authors: Winkels Raphael , Jedlicka Peter , Weise Felix K. , Schultz Christian , Deller Thomas , Schwarzacher Stephan W.
Published: January 2009

The submembrane cytoskeletal meshwork of the axon contains the scaffolding protein βIV‐spectrin. It provides mechanical support for the axon and anchors membrane proteins. Quivering (qv3j) mice lack functional βIV‐spectrin and have reduced voltage‐gated sodium channel (VGSC) immunoreactivity at the axon initial segment and nodes of Ranvier. Because VGSCs are critically involved in action potential generation and conduction, we hypothesized that qv3j mice should also show functional deficits at the network level. To test this hypothesis, we investigated granule cell function in the dentate gyrus of anesthetized qv3j mice after electrical stimulation of the perforant path in vivo. This revealed an impaired input‐output relationship between stimulus intensity and granule cell population spikes and an enhanced paired‐pulse inhibition of population spikes, indicating a reduced ability of granule cells to generate action potentials and decreased network excitability. In contrast, the input‐output curve for evoked field excitatory postsynaptic potentials (fEPSPs) and paired‐pulse facilitation of fEPSPs were unchanged, suggesting normal excitatory synaptic transmission at perforant path‐granule cell synapses in qv3j mutants. To corroborate our findings, we analyzed the influence of VGSC density reduction on dentate network activity using an established computational model of the dentate gyrus network. This in silico approach confirmed that the loss of VGSCs is sufficient to explain the electrophysiological changes observed in qv3j mice. Taken together, our findings demonstrate that βIV‐spectrin is required for normal granule cell firing and for physiological levels of network excitability in the mouse dentate gyrus in vivo. © 2009 Wiley‐Liss, Inc.
Synaptic potentiation induces increased glial coverage of excitatory synapses in CA1 hippocampus
Authors: Lushnikova Irina , Skibo Galina , Muller Dominique , Nikonenko Irina
Published: January 2009

Patterns of activity that induce synaptic plasticity at excitatory synapses, such as long‐term potentiation, result in structural remodeling of the postsynaptic spine, comprising an enlargement of the spine head and reorganization of the postsynaptic density (PSD). Furthermore, spine synapses represent complex functional units in which interaction between the presynaptic varicosity and the postsynaptic spine is also modulated by surrounding astroglial processes. To investigate how activity patterns could affect the morphological interplay between these three partners, we used an electron microscopic (EM) approach and 3D reconstructions of excitatory synapses to study the activity‐related morphological changes underlying induction of synaptic potentiation by theta burst stimulation or brief oxygen/glucose deprivation episodes in hippocampal organotypic slice cultures. EM analyses demonstrated that the typical glia‐synapse organization described in in vivo rat hippocampus is perfectly preserved and comparable in organotypic slice cultures. Three‐dimensional reconstructions of synapses, classified as simple or complex depending upon PSD organization, showed significant changes following induction of synaptic potentiation using both protocols. The spine head volume and the area of the PSD significantly enlarged 30 min and 1 h after stimulation, particularly in large synapses with complex PSD, an effect that was associated with a concomitant enlargement of presynaptic terminals. Furthermore, synaptic activity induced a pronounced increase of the glial coverage of both pre‐ and postsynaptic structures, these changes being prevented by application of the NMDA receptor antagonist D‐2‐amino‐5‐phosphonopentanoic acid. These data reveal dynamic, activity‐dependent interactions between glial processes and pre‐ and postsynaptic partners and suggest that glia can participate in activity‐induced structural synapse remodeling. © 2009 Wiley‐Liss, Inc.
Normal spectral emittance of a nickel metal surface with rectangular microcavities
Authors: Hirashima Daisuke , Kameya Yuki , Hanamura Katsunori
Published: January 2009

Spectral control of thermal radiation emitted from rectangular microcavities (0.5×0.5×0.5µm3) was investigated through emission experiments at high temperatures. The microcavities were fabricated on a mirror‐finished Ni metal surface. Through measurement of the normal spectral emittance, the maximum emittance was obtained around a wavelength of 0.87µm, which was very close to that (0.894µm) estimated from the cavity resonance theory. The emittance reached a maximum value of 0.95, and then decreased drastically with increasing wavelength, from the cut‐off wavelength. For a longer wavelength range from 1.7µm, it was equal to the emittance of the mirror‐finished surface. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20248
In vivo acute toxicity of titanium dioxide nanoparticles to mice after intraperitioneal injection
Authors: Chen Jinyuan , Dong Xia , Zhao Jing , Tang Guping
Published: January 2009

Because of its excellent optical performance and electrical properties, TiO2 has a wide range of applications in many fields. It is often considered to be physiologically inert to humans. However, some recent studies have reported that nano‐sized TiO2 may generate potential harm to the environment and humans. In this paper the in vivo acute toxicity of nano‐sized TiO2 particles to adult mice was investigated. Mice were injected with different dosages of nano‐sized TiO2 (0, 324, 648, 972, 1296, 1944 or 2592 mg kg–1). The effects of particles on serum biochemical levels were evaluated at various time points (24 h, 48 h, 7 days and 14 days). Tissues (spleen, heart, lung, kidney and liver) were collected for titanium content analysis and histopathological examination. Treated mice showed signs of acute toxicity such as passive behavior, loss of appetite, tremor and lethargy. Slightly elevated levels of the enzymes alanine aminotransferase and aspartate aminotransferase were found from the biochemical tests of serum whereas blood urea nitrogen was not significantly affected (P <0.05). The accumulation of TiO2 was highest in spleen (P <0.05). TiO2 was also deposited in liver, kidney and lung. Histopathological examinations showed that some TiO2 particles had entered the spleen and caused the lesion of spleen. Thrombosis was found in the pulmonary vascular system, which could be induced by the blocking of blood vessels with TiO2 particles. Moreover, hepatocellular necrosis and apoptosis, hepatic fibrosis, renal glomerulus swelling and interstitial pneumonia associated with alveolar septal thickening were also observed in high‐dose groups. Copyright © 2009 John Wiley & Sons, Ltd.
Plasmapheresis therapy for rare but potentially fatal reaction to rituximab
Authors: Hastings Deborah , Patel Bhavesh , Torloni Antonio Sergio , Mookadam Farouk , Betcher Jeffrey , Moss Adyr , Heilman Raymond , Mazur Marek , Hamawi Khaled , Mulligan David , Reddy Kunam , Mekeel Kristin , Chakkera Harini
Published: January 2009

Rituximab (Rituxan), a genetically engineered chimeric murine and human IgG1 monoclonal antibody directed against CD20 antigen, is an emerging drug used for a wide spectrum of disease processes and found to be relatively safe. We report a near‐fatal reaction to rituximab, which started 30 min after infusion and worsened over 24 to 48 h, resulting in hemodynamic and respiratory compromise that necessitated both intubation and high‐dose vasopressors. Subsequent treatment with plasmapheresis helped stabilize and improve the patient's clinical condition, and the patient was discharged home on hospital day 5. There is no specific treatment for these severe and sometimes fatal reactions except supportive care with plasmapheresis. With the increased use of rituximab therapy in the medical management of numerous diseases, those in the medical community need to be cognizant of the rare fatal or near‐fatal infusion reaction and the benefit that may accrue from plasmapheresis therapy. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.
ADAMTS13 activity levels in patients with human immunodeficiency virus‐associated thrombotic microangiopathy and profound CD4 deficiency
Authors: Park Yara A. , Hay Shauna N. , Brecher Mark E.
Published: January 2009

Background:

Thrombotic microangiopathy (TMA) encompasses a number of disorders with hemolytic anemia and thrombocytopenia, including thrombotic thrombocytopenic purpura (TTP). A deficiency in ADAMTS13 enzyme levels, along with an inhibitory antibody, is found in most patients with idiopathic TTP. Patients with human immunodeficiency virus (HIV) infection can have a TTP‐like illness; however, it appears to have a different etiology.

Methods:

A retrospective review of patients who had an ADAMTS13 activity level performed from 2005 through 2007 was completed. Patients with a diagnosis of HIV infection with TMA were investigated.

Results:

Two patients were identified. Case 1: a 47‐year‐old man with HIV infection and a CD4 count <10/μL presented with altered mental status, pneumonia, acute renal failure, thrombocytopenia, and anemia. The ADAMTS13 level was 71%. He was treated with plasma infusion. Two days after admission, he expired because of respiratory distress syndrome and metabolic lactic acidosis. Case 2: a 39‐year‐old man with HIV infection and a CD4 count of 9/μL presented with chest pain, acute renal failure, thrombocytopenia, and anemia. The ADAMTS13 level was 65%. He received multiple units of fresh frozen plasma without significant improvement in his platelet count. Six days after admission, the patient began highly active antiretroviral therapy, which resulted in a rapid increase in his platelet count.

Conclusions:

HIV‐associated TMA is postulated to have a different pathophysiology than idiopathic TTP. This study supports that assumption because both patients exhibited many of the classic findings of TTP but did not have a deficiency of ADAMTS13. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.
Low magnitude and high frequency mechanical loading prevents decreased bone formation responses of 2T3 preosteoblasts
Authors: Patel Mamta J. , Chang Kyungh Hwa , Sykes Michelle C. , Talish Roger , Rubin Clinton , Jo Hanjoong
Published: January 2009

Bone loss due to osteoporosis or disuse such as in paraplegia or microgravity is a significant health problem. As a treatment for osteoporosis, brief exposure of intact animals or humans to low magnitude and high frequency (LMHF) mechanical loading has been shown to normalize and prevent bone loss. However, the underlying molecular changes and the target cells by which LMHF mechanical loading alleviate bone loss are not known. Here, we hypothesized that direct application of LMHF mechanical loading to osteoblasts alters their cell responses, preventing decreased bone formation induced by disuse or microgravity conditions. To test our hypothesis, preosteoblast 2T3 cells were exposed to a disuse condition using the random positioning machine (RPM) and intervened with an LMHF mechanical load (0.1–0.4 g at 30 Hz for 10–60 min/day). Exposure of 2T3 cells to the RPM decreased bone formation responses as determined by alkaline phosphatase (ALP) activity and mineralization even in the presence of a submaximal dose of BMP4 (20 ng/ml). However, LMHF mechanical loading prevented the RPM‐induced decrease in ALP activity and mineralization. Mineralization induced by LMHF mechanical loading was enhanced by treatment with bone morphogenic protein 4 (BMP4) and blocked by the BMP antagonist noggin, suggesting a role for BMPs in this response. In addition, LMHF mechanical loading rescued the RPM‐induced decrease in gene expression of ALP, runx2, osteomodulin, parathyroid hormone receptor 1, and osteoglycin. These findings suggest that preosteoblasts may directly respond to LMHF mechanical loading to induce differentiation responses. The mechanosensitive genes identified here provide potential targets for pharmaceutical treatments that may be used in combination with low level mechanical loading to better treat osteoporosis or disuse‐induced bone loss. J. Cell. Biochem. 106: 306–316, 2009. © 2009 Wiley‐Liss, Inc.
Identifying and screening for psychological and comorbid medical and psychological disorders in medical settings
Authors: Kessler Rodger
Published: January 2009

There is increased attention to the medical and economic consequences of psychological problems comorbid with medical issues. There is also a clear awareness that most psychological problems are assessed and responded to in nonpsychiatric medical settings. This has furthered interest and attention in implementing screening procedures to better identify psychological, behavioral, and substance abuse problems in medical settings. Such interest is taking the form of recommendations from federal government task forces, and the funding of large projects to include screening in medical settings. At the same time there has been further attention to brief, valid, and reliable measures with which to capture psychological comorbidities. However, there have been multiple concerns raised about a variety of issues concerning the utility and effectiveness of such screening procedures and the identification of multiple issues to be considered in screening design. The author outlines and reviews the rationale and concerns about screening, identifies the issues that need to be considered in screening program development, and describes the efforts to develop a screening capacity in a rural family practice. © 2009 Wiley Periodicals, Inc. J Clin Psychol: In Session 65:1–15, 2009.
The importance of signal pathway modulation in all aspects of tooth development
Authors: Tummers Mark , Thesleff Irma
Published: January 2009

Most characteristics of tooth shape and pattern can be altered by modulating the signal pathways mediating epithelial–mesenchymal interactions in developing teeth. These regulatory signals function in complex networks, characterized by an abundance of activators or inhibitors. In addition, multiple specific inhibitors of all conserved signal pathways have been identified as modulators in tooth development. The number of teeth as well as molar cusp patterns can be modified by tinkering with several different signal pathways. The inhibition of any of the major conserved signal pathways in knockout mice leads to arrested tooth formation. On the other hand, the stimulation of the Wnt pathway in the oral epithelium in transgenic mice leads to abundant de novo tooth formation. The modulation of some of the signal pathways can rescue the development of vestigial tooth rudiments in the incisor and molar regions resulting in extra premolar‐like teeth. The size and the degree of asymmetry of the continuously growing mouse incisor can be modulated by modifying the complex network of FGF, bone morphogenetic protein, and Activin signals, which regulate the proliferation and differentiation of epithelial stem cells. Follistatin, Sprouty, and Sostdc1 are important endogenous inhibitors antagonizing these pathways and they are also involved in regulation of enamel formation, and patterning of teeth in crown and root domains. All these findings support the hypothesis that the diversity of tooth types and dental patterns may have resulted from tinkering with the conserved signal pathways, organized into complex networks, during evolution. J. Exp. Zool. (Mol. Dev. Evol.) 312B:309–319, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis and radiolabelling of Re(CO)3‐β‐elemene derivatives as potential therapeutic radiopharmaceuticals
Authors: Ren Yunfeng , Sun Yanhong , Cheng Kangmin , Liu Guifeng , Shen Yumei
Published: January 2009

β‐Elemene, (1S, 2S, 4R)‐(−)‐(1‐methy‐1‐vinyl‐2,4‐diisopropenyl cyclohexane) is an anticancer agent from the Traditional Chinese Herb Medicinal. Three novel Re(CO)3‐β‐elemene derivatives including their radioactive conjugates containing N,N,N tridentate ligands and tricarbonyl rhenium (complex 12, 13, 14) were synthesized. Their structures were characterized by infrared (IR), 1H‐NMR and HRMS. Good radioactive yield (above 90%) and radioactive chemical purity with Re‐188 (above 95%) were obtained for all of the three derivatives (complex 15, 16, 17). The antiproliferative activity of non‐radioactive β‐elemene‐Re(CO)3 derivatives on Lewis lung cancer cells and HeLa cell lines were evaluated by WST‐1 methods. The result shows substantial decrease in IC50 values compared with the parent compound β‐elemene. The synthesis and radiosynthesis of β‐elemene tricarbonyl rhenium conjugates provide the possibility to find a new kind of potential radiopharmaceuticals on β‐elemene. Copyright © 2009 John Wiley & Sons, Ltd.
Proteomic analysis of optic nerve lipid rafts reveals new paranodal proteins
Authors: Ogawa Yasuhiro , Rasband Matthew N.
Published: January 2009

Neuron–glia interactions at paranodal junctions play important roles in action potential propagation. Among their many functions, they contribute to the passive electrical properties of myelinated nerve fibers and actively regulate the polarized distribution of ion channels along axons. Despite their importance, relatively little is known about the molecules responsible for paranode formation and function. Paranodal junction formation apparently depends on interactions among three cell adhesion molecules: caspr and contactin on the axon and neurofascin 155 (NF‐155) on the glial membrane. Using Caspr‐null paranodal mutant mice, we demonstrate that loss of paranodal junctions causes failure of NF‐155 to partition into lipid rafts, indicating that proteins located at paranodal junctions have biochemical characteristics of lipid raft‐associated proteins. Based on this property of paranodal junctions, mass spectrometry of lipid rafts isolated from a pure white matter tract (optic nerve) was used to search for new paranodal proteins. Because we used a relatively crude biochemical preparation, we identified several hundred different proteins. Among these, we found all previously described paranodal proteins. Further analysis based on antibody staining of central and peripheral nerves revealed β‐adducin, septin 2, and sh3p8 as putative paranodal proteins. We describe the localization of these proteins in relation to other markers of nodes, paranodes, and juxtaparanodes in adult and developing nerve fibers. Finally, we describe their distribution in dysmyelinating TremblerJ mice, a model for the peripheral neuropathy Charcot‐Marie‐Tooth disease. © 2009 Wiley‐Liss, Inc.
p75NTR Expression is induced in isolated neurons of the penumbra after ischemia by cortical devascularization
Authors: Angelo Maria Florencia , Aviles‐Reyes Rolando X. , Villarreal Alejandro , Barker Phil , Reines Analia G. , Ramos Alberto Javier
Published: January 2009

The p75 neurotrophin receptor (p75NTR) is involved in neuronal functions ranging from induction of apoptosis and growth inhibition to the promotion of survival. p75NTR expression is induced in the central nervous system (CNS) by a range of pathological conditions, where it seems to have a role in neuronal death and axonal growth inhibition. The cellular mechanisms driving p75NTR expression in cell lines and primary neurons is Sp1 dependent (Ramos et al. [2007] J. Neurosci. 27:1498). In this study, we analyzed the spatiotemporal profile of p75NTR expression after an ischemic lesion induced by cortical devascularization (CD). Our results show that p75NTR expression occurs in isolated neurons of the ischemic lesion site. The p75NTR+ neurons presented morphological alterations and active caspase‐3 staining. Some p75NTR+ neurons were also positive for sortilin. The peak of p75NTR expression was localized 3 days postlesion (3DPL) in the penumbra. Sp1 transcription factor nuclear localization was observed in p75NTR+ neurons. The overall level of Sp1 expression was increased until 14DPL on the ipsilateral hemisphere. With primary cortical neurons, we demonstrated that p75NTR expression is induced by excitotoxic stress and correlated with increased Sp1 abundance. We conclude that p75NTR expression is localized in selected neurons of the ischemic lesion and that these neurons are probably condemned to apoptotic cell death. In primary neuronal culture, it is clear that excitotoxity and Sp1 are involved in induction of p75NTR expression, although, in vivo, some additional mechanisms are likely to be involved in the control of p75NTR expression in specific neurons in vivo. © 2009 Wiley‐Liss, Inc.
Determination of D,L‐serine in midbrain of Parkinson's disease mouse by capillary electrophoresis with in‐column light‐emitting diode induced fluorescence detection
Authors: Li Shuting , Yu Qinglei , Lu Xin , Zhao Shulin
Published: January 2009

A capillary electrophoresis method with in‐column light‐emitting diode induced fluorescence detection is described for simultaneous determination of D,L‐serine in the midbrain of a Parkinson's disease mouse. D,L‐Serine was derivatized with fluorescein isothiocyanate, and chiral separation and determination of D,L‐serine derivatives were performed on a laboratory‐built capillary electrophoresis system with in‐column light‐emitting diode induced fluorescence detector using γ‐cyclodextrin as chiral selector. Using this method, the levels of D‐ and L‐serine in the midbrains of Parkinson's disease mice were determined. When compared to controls, the levels of D‐ and L‐serine showed significant differences. The result suggested that the biosynthesis and the transportation of endogenous D,L‐serine may participate in Parkinson's disease pathogenesis.
Use of fullerene‐, octadecyl‐, and triaconthyl silica for solid phase extraction of tryptic peptides obtained from unmodified and in vitro glycated human serum albumin and fibrinogen
Authors: Böddi Katalin , Takátsy Anikó , Szabó Szilvia , Markó Lajos , Márk László , Wittmann István , Ohmacht Róbert , Montskó Gergely , Vallant Rainer M. , Ringer Thomas , Bakry Rania , Huck Christian W. , Bonn Günther K. , Szabó Zoltán
Published: January 2009

SPE plays a crucial role in bioanalytical research. In the present work a novel fullerene(C60)‐derivatised silica material is compared with octadecyl(C18) – and triaconthyl(C30)‐silicas regarding recoveries of peptides and sequence coverage of HSA and fibrinogen digests. C30‐ and C60(30 nm)‐SPE materials were found to be the two most prominent SPE materials. At low peptide concentrations C60‐material prepared from a silica gel with a pore size of 30 nm has proven to be the best material with regards to recoveries. By increasing the amount of loaded peptides recoveries decrease due to its relative low binding capacity in contrast to C30‐silica particles, showing no changes. The best sequence coverages of Aα‐ and Bβ‐chains of 20 pmol fibrinogen digest can also be achieved using these two SPE materials, C60 (30 nm) demonstrates an outstanding value of sequence coverage (62.15%) achieved for the γ‐chain. After nonenzymatic glycation the digests of fibrinogen and HSA were also separated. This makes the detection of a considerably higher number of glycated peptides possible compared to the unfractionated digests and the use of boronate affinity chromatography in the case of fibrinogen. For HSA, ten new sites of glycation at lysine and arginine residues have been explored. Using the detailed SPE/off‐line MALDI method the glycation sites on fibrinogen are first described in this paper.
Unique potentiometric detection systems for HPLC determination of some steroids in human urine
Authors: Vissers Bert , Everaert Joseph , Sekula Justyna , Malak Anna , Bohets Hugo , Bazylak Grzegorz , Nagels Luc J.
Published: January 2009

Isocratic HPLC with potentiometric detection is used for the determination of some 17‐ketosteroids (17‐KS), e.g., androsterone, dehydroepiandrosterone and estrone, and their respective sulfated conjugates (17‐KSS). Glassy carbon or composite electrodes containing a mixture of graphite and poly(vinyl chloride), PVC, were used as substrate electrodes. These substrates were covered either by montmorillonite or potassium tetrakis(p‐chlorophenyl) borate containing PVC‐based rubber phase membranes. The neutral 17‐KS compounds were derivatized with Girard's reagent P (GP) to obtain cationic pyridinium acetohydrazones prior to the HPLC/potentiometric detection assay. No side reactions were observed, and the GP itself was not interfering. The method yielded accurate and reproducible results and was applicable to samples containing down to micromolar concentrations. Next, the 17‐KSS compounds, acting as anionic charged molecules, were determined directly in human urine samples with the HPLC/potentiometry combination without preliminary derivatization. For this purpose, a new anion‐sensitive potentiometric electrode was developed using a macrocyclic polyamine containing, PVC‐based, rubber phase membrane. The three 17‐KSS compounds were also determined accurately down to micromolar concentrations. Especially, the main androgen metabolites as dehydroepiandrosterone sulfate and androsterone sulfate could be selectively determined with a developed potentiometric sensor in human urine samples without time‐consuming cleanup and preconcentration step.
Method to predict the bandwidth of elution profile under the linear gradient elution in reversed‐phase HPLC
Authors: Lee Ju Weon , Row Kyung Ho
Published: January 2009

Solute migration in a chromatographic column is an important consideration when designing batch or continuous chromatographic separation processes. Most design methods for the chromatographic processes are based on the equilibrium theory which concerns only the migration velocity of the solute. However, in real cases, it is important to predict the zone spreading which occurs by axial dispersion and mass transfer resistance. To predict the actual solute profiles in the column or effluent stream, numerical methods to solve nonlinear partial differential equations have been used. However, these methods involve much time and expense. In this work, two different rate factors are considered to predict the characteristics of the solute profiles. The first is solute migration velocity and the second is the zone spreading rate. The zone spreading rate can be estimated by the apparent axial dispersion coefficient which is obtained from the height of the equivalent theoretical plate in particular. Four benzene derivatives (benzene, toluene, p‐xylene, and acetophenone) were used as model solutes, and two mobile phase systems, water/methanol and water/ACN, were used in RP‐HPLC. The bandwidths and retention times of the solutes were predicted under several linear gradient conditions. The predicted and experimental bandwidths and retention times showed good agreement.
Effect of Head Size in Head‐Tail‐Type Polycations on their in vitro Performances as Nonviral Gene Vectors
Authors: Harada Atsushi , Kawamura Masanori , Kimura Yuka , Takahashi Toshinari , Kojima Chie , Kono Kenji
Published: January 2009

Three kinds of head‐tail‐type block copolymers composed of polyamidoamine (PAMAM) dendron heads and poly(L‐lysine) (PLL) tail blocks (PAMAM dendron‐PLL), having PAMAM dendrons with different generations (G2.5‐PLL, G3.5‐PLL and G4.5‐PLL) were synthesized. Some of the dendron heads were located at polyplex surface, and G2.5‐PLL and G3.5‐PLL could form small polyplexes (less than 150 nm in size). G2.5‐PLL and G3.5‐PLL polyplexes were taken up into the cells more effectively. PAMAM dendron‐PLL that had a larger dendron head could show a more‐effective buffering effect. The in vitro performance of the PAMAM dendron‐PLL polyplexes was controlled by the balance of cellular uptake and endosomal escape by a buffering effect.

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Weakly associative relation algebras with projections
Authors: Kurucz Agi
Published: January 2009

Built on the foundations laid by Peirce, Schröder, and others in the 19th century, the modern development of relation algebras started with the work of Tarski and his colleagues [21, 22]. They showed that relation algebras can capture strong first‐order theories like ZFC, and so their equational theory is undecidable. The less expressive class WA of weakly associative relation algebras was introduced by Maddux [7]. Németi [16] showed that WA's have a decidable universal theory. There has been extensive research on increasing the expressive power of WA by adding new operations [1, 4, 11, 13, 20]. Extensions of this kind usually also have decidable universal theories. Here we give an example – extending WA's with set‐theoretic projection elements – where this is not the case. These “logical” connectives are set‐theoretic counterparts of the axiomatic quasi‐projections that have been investigated in the representation theory of relation algebras [22, 6, 19]. We prove that the quasi‐equational theory of the extended class PWA is not recursively enumerable. By adding the difference operatorDone can turn WA and PWA to discriminator classes where each universal formula is equivalent to some equation. Hence our result implies that the projections turn the decidable equational theory of “WA +D” to non‐recursively enumerable (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determinacy of Wadge classes and subsystems of second order arithmetic
Authors: Nemoto Takako
Published: January 2009

In this paper we study the logical strength of the determinacy of infinite binary games in terms of second order arithmetic. We define new determinacy schemata inspired by the Wadge classes of Polish spaces and show the following equivalences over the system RCA0*, which consists of the axioms of discrete ordered semi‐rings with exponentiation, Δ10 comprehension and Π00 induction, and which is known as a weaker system than the popularbase theory RCA0:
1. Bisep(Δ10, Σ10)‐Det* ↔ WKL0,

2. Bisep(Δ10, Σ20)‐Det* ↔ ATR0 + Σ11 induction,

3. Bisep(Σ10, Σ20)‐Det* ↔ Sep(Σ10, Σ20)‐Det* ↔ Π11‐CA0,

4. Bisep(Δ20, Σ20)‐Det* ↔ Π11‐TR0,
where Det* stands for the determinacy of infinite games in the Cantor space (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A characterization of constructive dimension
Authors: Nandakumar Satyadev
Published: January 2009

In the context of Kolmogorov's algorithmic approach to the foundations of probability, Martin‐Löf defined the concept of an individual random sequence using the concept of a constructive measure 1 set. Alternate characterizations use constructive martingales and measures of impossibility. We prove a direct conversion of a constructive martingale into a measure of impossibility and vice versa such that their success sets, for a suitably defined class of computable probability measures, are equal. The direct conversion is then generalized to give a new characterization of constructive dimensions, in particular, the constructive Hausdorff dimension, the constructive packing dimension, and their generalizations, the constructive scaled dimension and the constructive scaled strong dimension (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a question of Andreas Weiermann
Authors: Kotlarski Henryk , Zdanowski Konrad
Published: January 2009

We prove that for each β, γ < ε0 there existsα < ε0 such that whenever A ⊆ ω is α ‐large and G: A → β is such that (∀a ∈ A)(psn(G (a)) ≤ a), then there exists a γ ‐large C ⊆ A on which G is nondecreasing. Moreover, we give upper bounds for α for small ordinals β ≤ ω (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The matricial Schur problem in both nondegenerate and degenerate cases
Authors: Fritzsche Bernd , Kirstein Bernd , Lasarow Andreas
Published: January 2009

The principal object of this paper is to present a new approach simultaneously to both nondegenerate and degenerate cases of the matricial Schur problem. This approach is based on an analysis of the central matrixvalued Schur functions which was started in [24]–[26] and then continued in [27]. In the nondegenerate situation we will see that the parametrization of the solution set obtained here coincides with the well‐known formula of D. Z. Arov and M. G. Kreĭn for that case (see [1]). Furthermore, we give some characterizations of the situation that the matricial Schur problem has a unique solution (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weighted Morrey spaces and a singular integral operator
Authors: Komori Yasuo , Shirai Satoru
Published: January 2009

In this paper, we shall introduce a weighted Morrey space and study the several properties of classical operatorsin harmonic analysis on this space (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pyrene‐Functionalised, Alternating Copolyimide for Sensing Nitroaromatic Compounds
Authors: Burattini Stefano , Colquhoun Howard M. , Greenland Barnaby W. , Hayes Wayne , Wade Mathew
Published: January 2009

A novel, pyrene‐functionalised copolymer has been synthesised in a single step via imidisation of poly(maleic anhydride‐alt‐1‐octadecene) with 1‐pyrenemethylamine, and its potential for the detection of volatile nitro aromatic compounds (NACs) evaluated. The new copolymer forms complexes in solution with NACs such as 2,5‐dinitrobenzonitrile, as shown by 1H NMR, UV‐vis and fluorescence spectroscopy. Moreover, thin films of this copolymer, cast from THF solution, undergo almost instantaneous fluorescence quenching when exposed to the vapour of 2,5‐dinitrobenzonitrile (a model for TNT) at ambient temperatures and pressures.

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Phase Behavior of a Weakly Interacting Polystyrene and Poly(n‐hexyl methacrylate) System: Evidence for the Coexistence of UCST and LCST
Authors: Ahn Hyungju , Naidu Sudhakar , Ryu Du Yeol , Cho Junhan
Published: January 2009

The phase behavior of a weakly interacting binary system composed of deuterated polystyrene (dPS) and poly(n‐hexyl methacrylate) (PnHMA) was investigated by the turbidity measurement for the binary blend, and by small angle X‐ray scattering (SAXS) and depolarized light scattering for the block copolymers. For the binary dPS/PnHMA blend, a new phase diagram involving both the upper critical solution transition (UCST) and lower critical solution transition (LCST) was observed by the delicate control of molecular weights between dPS and PnHMA. Whereas for the block copolymers such as dPS‐block‐PnHMA and PS‐block‐PnHMA, an order‐to‐disorder transition (ODT) on heating was observed within the experimental temperature range depending on the molecular weight. This coexistence of both a UCST and LCST in the dPS/PnHMA blend consequently represents the experimental evidence that the corresponding (d)PS‐b‐PnHMAs possess not only ODT, but also lower disorder‐to‐order transition (LDOT) character driven by a compressibility difference, although the latter is hindered by thermal degradation.

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The Peculiar Response of DNA Hydrogel Fibers to a Salt and pH Stimulus
Authors: Lee Sun Hee , Lee Chang Kee , Shin Su Ryon , Kim Sun I. , So Insuk , Kim Seon Jeong
Published: January 2009

DNA hydrogels which are composed of an entangled network without a crosslinker are synthesized and examined in regards to their sensitivity to salt and pH changes. The DNA hydrogel fibers only exhibited a marked response – that is a fast and large change in length – under biological conditions ([Na+] = 0.15 M at pH = 7) and are therefore suitable materials for bio‐inspired devices.

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Shell Cross‐Linked Micelles as Cationic Templates for the Preparation of Silica‐Coated Nanoparticles: Strategies for Controlling the Mean Particle Diameter
Authors: Li Yuting , Du Jianzhong , Armes Steven P.
Published: January 2009

The mean diameter of poly[2‐(dimethylamino)ethyl methacrylate]‐block‐poly[2‐(diisopropylamino)ethyl methacrylate] (PDMA‐PDPA) diblock copolymer micelles can be easily adjusted from 27–155 nm (as measured by DLS) by either selective quaternisation of the PDMA block or by adding PDPA homopolymer prior to micellisation; these self‐assembled nanostructures can be shell crosslinked with 1,2‐bis‐(2‐iodoethoxy)ethane and subsequently used as templates for the preparation of silica‐coated nanoparticles and, ultimately, hollow silica nanoparticles.

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Environmental and seasonal influences on red raspberry anthocyanin antioxidant contents and identification of quantitative traits loci (QTL)
Authors: Kassim Angzzas , Poette Julie , Paterson Alistair , Zait Dzeti , McCallum Susan , Woodhead Mary , Smith Kay , Hackett Christine , Graham Julie
Published: January 2009

Consumption of raspberries promotes human health through intake of pharmaceutically active antioxidants, including cyanidin and pelargonidin anthocyanins; products of flavonoid metabolism and also pigments conferring colour to fruit. Raspberry anthocyanin contents could be enhanced for nutritional health and quality benefits utilising DNA polymorphisms in modern marker assisted breeding. The objective was to elucidate factors determing anthocyanin production in these fruits. HPLC quantified eight anthocyanin cyanidin and pelargonidin glycosides: ‐3‐sophoroside, ‐3‐glucoside, ‐3‐rutinoside and ‐3‐glucosylrutinoside across two seasons and two environments in progeny from a cross between two Rubus subspecies, Rubus idaeus (cv. Glen Moy)×Rubus strigosus (cv. Latham). Significant seasonal variation was detected across pigments less for different growing environments within seasons. Eight antioxidants mapped to the same chromosome region on linkage group (LG) 1, across both years and from fruits grown in field and under protected cultivation. Seven antioxidants also mapped to a region on LG 4 across years and for both growing sites. A chalcone synthase (PKS 1) gene sequence mapped to LG 7 but did not underlie the anthocyanin quantitative traits loci (QTL) identified. Other candidate genes including basic‐helix‐loop‐helix (bHLH), NAM/CUC2‐like protein and bZIP transcription factor underlying the mapped anthocyanins were identified.
Association between functional FABP2 promoter haplotypes and body mass index: Analyses of 8072 participants of the KORA cohort study
Authors: Böhme Mike , Grallert Harald , Klapper Maja , Gieger Christian , Fischer Alexandra , Heid Iris , Wichmann H.‐Erich , Döring Frank , Illig Thomas
Published: January 2009

Studies in relatively small cohorts provide preliminary evidence that functional fatty acid binding protein 2 (FABP2) promoter haplotypes are associated with type 2 diabetes and BMI. Here, we studied the influence of the haplotypes on BMI by using 8072 male and female participants of the Kooperative Gesundheitsforschung in der Region Augsburg (KORA) cohort. By linear regression analysis, we found in males a reduction of –0.39 BMI units (95% CI: –0.73, –0.05, p = 0.024) in homozygous FABP2 promoter haplotype B carriers. Carriers of haplotype B showed a significant decrease in BMI of –0.19 BMI units (95% CI: –0.35, –0.02, p = 0.027). In accordance, a significant reduction in BMI of the minor haplotype carriers in the BMI point categories of 25–30 (BMI units: –0.10, 95% CI: –0.18, –0.01, p = 0.03) and < 30 (BMI units: –0.37, 95% CI: –0.67, –0.07, p = 0.02) were found. In summary, the minor FABP2 promoter haplotype B contributes to a reduced BMI in men. This provides evidence that functional FABP2 contributes to multifactorialy regulated body weight.
Client‐contractor bargaining on net present value in project scheduling with limited resources
Authors: Kavlak Nursel , Ulusoy Gündüz , Şerifoğlu Funda Sivrikaya , Birbil Ş. İlker
Published: January 2009

The client‐contractor bargaining problem addressed here is in the context of a multi‐mode resource constrained project scheduling problem with discounted cash flows, which is formulated as a progress payments model. In this model, the contractor receives payments from the client at predetermined regular time intervals. The last payment is paid at the first predetermined payment point right after project completion. The second payment model considered in this paper is the one with payments at activity completions. The project is represented on an Activity‐on‐Node (AON) project network. Activity durations are assumed to be deterministic. The project duration is bounded from above by a deadline imposed by the client, which constitutes a hard constraint. The bargaining objective is to maximize the bargaining objective function comprised of the objectives of both the client and the contractor. The bargaining objective function is expected to reflect the two‐party nature of the problem environment and seeks a compromise between the client and the contractor. The bargaining power concept is introduced into the problem by the bargaining power weights used in the bargaining objective function. Simulated annealing algorithm and genetic algorithm approaches are proposed as solution procedures. The proposed solution methods are tested with respect to solution quality and solution times. Sensitivity analyses are conducted among different parameters used in the model, namely the profit margin, the discount rate, and the bargaining power weights. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009