bluuebunny/crossref_metadata_2025 huggingface dataset:
Platinum and Palladium Complexes with Metal–Silicon Bonds. New Bonding, Structures, and Chemical Properties
Authors: Osakada Kohtaro , Tanabe Makoto
Published: October 2005

Studies on the Pt and Pd complexes with Si-containing ligands by the authors are reviewed. trans-[Pt(SiHPh2)2(PMe3)2], the first Pt(II) complex with two silyl ligands at trans positions, is equilibrated with the thermodynamically more stable cis isomer in solution. The reaction of dimethyl acetylenedicarboxylate (Z–C≡C–Z, Z=COOMe) with [Pt(SiHPh2)2(PMe3)2] produces 3-sila-1-propenylplatinum complex, cis-[Pt(CZ=CZSiHPh2)(SiHPh2)(PMe3)2], and 4-sila-3-platinacyclobutene, , depending on the reaction conditions. The former product is turned into the latter, accompanied by elimination of H2SiPh2. The spectroscopic data of cis-[Pt(CZ=CZSiHPh2)(SiHPh2)(PMe3)2] as well as the crystallographic structure of the 3-sila-1-propenylplatinum with a chelating bisphosphine, [Pt(CZ=CZSiHPh2)(SiHPh2)(dmpe)] (dmpe = 1,2-bis(dimethylphosphino)ethane), indicate intramolecular interaction of the γ-Si–H hydrogen of the ligand with the Pt center. The 4-sila-3-platinacyclobutene reacts with mono-substituted alkynes to produce various 5-sila-2-platina-1,4-cyclohexadienes via insertion of the C≡C bond into the Pt–Si bond of the four-membered ring. [Pt(SiHPh2)2(PMe3)2] reacts with nitriles to cause double addition of the Si–H bonds to the C≡N triple bond, yielding (R = Me and Ph). The reactions of H2SiPh2 and H2SiPhMe with [PdEt2(PMe3)2] afford dinuclear Pd complexes with bridging silyl ligands, [{Pd(PMe3)}{Pd(PMe3)n}(μ-HSiPhR)2] (R = Me and Ph; n = 1 and 2). Pd–Pt heterobimetallic complexes with bridging diphenylsilyl ligands, [{Pd(PR3)}{Pt(PR3)n}(μ-HSiPh2)2] (R = Et and Cy (cyclohexyl); n = 1 and 2), are obtained from the reactions of bis(silyl)platinum(II) complexes with palladium(0)–phosphine complexes. The heterobimetallic complex with PEt3 ligands reacts with t-butyl isocyanide to afford a new disilaplatinacyclopentane, . Heating of [Pt(SiHPh2)2(PMe3)2] at 80 °C in solution produces a trinuclear Pt complex with bridging diphenylsilylene ligands, [{Pt(PMe3)}3(μ-SiPh2)3], which was characterized by X-ray crystallography, NMR spectroscopy, and theoretical calculations.
Discrimination of Copper(II) Ions and Humate Complexes by Successive Desorption from Thiacalix[4]arenetetrasulfonate-Loaded Sephadex A-25
Authors: Matsumiya Hiroaki , Hiraide Masataka
Published: October 2005

A facile method for the analytical fractionation of copper humates and free copper(II) species is described. A chelating agent, thiacalix[4]arenetetrasulfonate (TCAS, 20 μmol), was electrostatically immobilized onto a strongly basic anion-exchanger, QAE-Sephadex A-25 (50 mg). The resulting TCAS-loaded Sephadex A-25 was packed into a column (6 mm i.d. × 7 mm high) and a water sample (10–50 cm3) was passed through the column to collect both copper humates and free copper(II) species. A 1.0-cm3 volume of 0.01 mol dm−3 nitric acid was passed through the column to selectively desorb the copper complexed with humic substances. Subsequently, 1.0 cm3 of 1 mol dm−3 nitric acid was passed through the same column to desorb the remaining copper, the fraction of free copper(II) species. The proposed two-step desorption method was successfully applied to the speciation analysis of copper in natural water samples by graphite-furnace atomic absorption spectrometry.
Speciation and Excretion Patterns of Arsenic Metabolites in Human Urine after Ingestion of Edible Seaweed, Hizikia fusiforme
Authors: Matsuura Hirotaka , Asano Motoki , Hasegawa Takuya , Umemura Tomonari , Haraguchi Hiroki
Published: October 2005

Chemical speciation of arsenic in human urine was performed by HPLC separation with ICP-MS detection in order to investigate the urinary excretion patterns of arsenic metabolites after one-time ingestion of an edible seaweed, hijiki (Hizikia fusiforme). A Japanese male volunteer ingested one serving of ca. 15 g (dry weight) of hijiki (containing ca. 0.9 mg of arsenic), and urine samples were collected at 3–5 h intervals for the following 3 days. As a result, different urinary excretion patterns were observed between inorganic and methylated arsenicals. Toxic inorganic As(V) and As(III) were detected in the urine 3 h after ingestion. The highest concentrations of As(V) and As(III) were observed at 6 and 15 h after ingestion, respectively. In contrast, methylated arsenic species in the urine, such as monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AB), began to increase 10 h after ingestion and provided the highest concentrations at 21 h after ingestion. These results indicate that a large amount of As(V) from hijiki is excreted rapidly in urine and some part of it is reduced to As(III) in the human body. As(III) may then be converted to non-toxic methylated arsenic species and excreted in urine later than inorganic ones. It can be concluded from these experimental results that detoxification of arsenic occurs in the human body through the rapid urinary excretion of toxic arsenicals or by conversion to organic methylated ones after ingestion of hijiki.
Characterization of Water-Extractable Amino Acids in the Sub-Surface of Semi-Permafrost Environments
Authors: Takano Yoshinori , Gupta Lallan P , Kawahata Hodaka , Kobayashi Kensei , Marumo Katsumi
Published: October 2005

Terrestrial core samples of semi-permafrost sediment were analyzed for total free amino acids (TFAA). The TFAA content ranged from 12.0 to 460.2 nmol/g of sediment, and generally consisted of protein amino acids as the most abundant component of TFAA. The depth profiles in terms of the content drastically decreased with the depth, followed by the vertical distribution patterns of total hydrolyzed amino acids (THAA) within the same sediment. The abundance of THAA was 14 to 327 times larger than that of TFAA. Plots of TFAA versus THAA values yielded a straight line, as defined by the equation THAA = 10.1 × TFAA1.4 (R2 = 0.86) based on the least-squares method. The molar ratio of β-alanine and γ-aminobutyric acid did not increase with the depth via diagenesis, as was the case in the THAA fraction. On the other hand, the molar ratio of basic amino acids such as histidine and ornithine gradually decreased with increasing depth. The present study determined that the major organic matter content in the sediment consisted not of free, but bound amino acid analogs.
Influence of Cyclodextrin Encapsulation on Norrish–Yang Photoreaction of Valerophenone
Authors: Annalakshmi Subramanian , Pitchumani Kasi
Published: October 2005

In the solid-state Norrish–Yang photoreaction of valerophenone, studied in presence of various cyclodextrins, not only was elimination suppressed, but a remarkable diastereoselectivity was also observed. The predominant formation of one cyclobutanol (C1-trans) is rationalized as being due to a restricted rotational motion of the 1,4-biradical, and also stabilization of the same by hydroxyl groups present in the rim of the cyclodextrin cavity. Additional supports for the coinclusion of a side chain into the γ-CD cavity from molecular minimization calculations and 1H–1H NOESY spectra are also presented.
Porphyrin Capped with Calix[4]arene Derivative via Hydrogen Bonds
Authors: Arai Satoshi , Ohkawa Haruki , Ishihara Shinsuke , Shibue Toshimichi , Takeoka Shinji , Nishide Hiroyuki
Published: October 2005

A calix[4]arene–porphyrin duplex was prepared by mixing equimolar amounts of hydroxy or carboxy calix[4]arene derivatives and pyridyl or o-aminophenylporphyrin derivatives. Electrospray ionization mass spectrometry (ESI-MS) was applied to screen a suitable pair of a calix[4]arene and a porphyrin. meso-Tetra(2-pyridyl)porphyrin formed a duplex with tetrahydroxy or tetrahydroxymethylcalix[4]arene via triple or quadruple hydrogen bonds. 1H NMR spectra showed that the tetrahydroxycalix[4]arene was symmetrically located upon the porphyrin ring, whereas trihydroxycalix[4]arene was slanted on the porphyrin ring. The duplex of meso-tetra(2-pyridyl)porphyrinatocobalt(II) and tetrahydroxymethylcalix[4]arene formed a complex with benzylimidazole, which was capable of reversible dioxygen-binding. The capping structure upon porphyrin provided by calix[4]arene raised the life-time of dioxygen-adduct compared with the porphyrin without calix[4]arene.
A Tris(carbene) Constructed with Stable Triplet Carbene Units
Authors: Tsuchiya Yoko , Matsuno Masayoshi , Itoh Tetsuji , Hirai Katsuyuki , Tomioka Hideo
Published: October 2005

Bis[10-(4-t-butyl-2,6-dimethylphenyl)-9-anthryl]diazomethane, which can generate a fairly stable triplet carbene that can survive for even a week in solution at room temperature, was shown to be stable enough to undergo a Sonogashira coupling reaction. Thus, three units of the diazo compounds were connected through an ethynyl group on 1,3,5-positions of benzene. The species generated by irradiation of the resulting tris(diazo) compound were characterized by variable temperature ESR and SQUID measurements. The results indicated the generation of the corresponding tris(carbene), that exhibits only weak exchange between carbene units. This fits the fact that dianthrylcarbenes are connected to the central phenyl ring across nodal (inactive) sites. The anomalously high thermal stability and chemical inertness of the species were shown by variable temperature and time-resolved UV–vis spectroscopic studies. The tris(carbenes) are shown to survive hours in solution at room temperature.
Synthesis and Dynamic Stereochemistry of Azulene-Substituted 9-Fluorenyl, 9,10-Dihydro-10,10-dimethyl-9-anthryl, 10,11-Dihydro-5H-dibenzo[a,d]cyclohepten-5-yl, and 5H-Dibenzo[a,d]cyclohepten-5-yl Cations. Correlations of Stabilities of the Carbocations and Rotational Barrier of Azulene Ring
Authors: Ito Shunji , Kawakami Jun , Tajiri Akio , Ryuzaki Daisuke , Morita Noboru , Asao Toyonobu , Watanabe Masataka , Harada Nobuyuki
Published: October 2005

The carbocations in the title: 9-(1-Azulenyl)-9-fluorenyl, 9-(1-azulenyl)-9,10-dihydro-10,10-dimethyl-9-anthryl, 5-(1-azulenyl)-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-yl, and 5-(1-azulenyl)-5H-dibenzo[a,d]cyclohepten-5-yl cations (4c, 5a–c, 6a–c, and 7a–c) were prepared by hydride abstraction of the corresponding hydrocarbon derivatives and their properties were fully characterized. The pKR+ values of 4c, 5a–c, 6a–c, and 7a–c were determined as −2.7, 0.5–2.7, 8.4–9.1, and 7.4–8.5, respectively, which were higher by 8.1, 6.0–8.2, 15.1–16.1, and 13.1–14.3 pK units, respectively, than those of the corresponding phenyl derivatives. Conformations and energy barriers for 4c, 5a–c, 6a–c, and 7a–c were studied by means of dynamic nuclear magnetic resonance spectroscopy (DNMR) techniques. The thermodynamic stability of the cations and the barrier to the rotation of the 1-azulenyl group were significantly affected by not only the electron density effect but also the dynamic stereochemistry of the connected-ring systems.
Synthesis of Oriented Layered Double Hydroxide Thin Films on Sulfonated Polystyrene Substrates
Authors: Lei Xiaodong , Yang Lan , Zhang Fazhi , Evans David Geraint , Duan Xue
Published: October 2005

Oriented dense thin films of LDHs may be grown on sulfonated polystyrene substrates with the (00l) direction of the LDH platelets perpendicular to the surface of the substrate.
Binding of misacylated tRNAs to the ribosomal A site
Authors: DALE TARAKA , UHLENBECK OLKE C.
Published: October 2005

To test whether the ribosome displays specificity for the esterified amino acid and the tRNA body of an aminoacyl-tRNA (aa-tRNA), the stabilities of 4 correctly acylated and 12 misacylated tRNAs in the ribosomal A site were determined. By introducing the GAC (valine) anticodon into each tRNA, a constant anticodon·codon interaction was maintained, thus removing concern that different anticodon·codon strengths might affect the binding of the different aa-tRNAs to the A site. Surprisingly, all 16 aa-tRNAs displayed similar dissociation rate constants from the A site. These results suggest that either the ribosome is not specific for different amino acids and tRNA bodies when intact aa-tRNAs are used or the specificity for the amino acid side chain and tRNA body is masked by a conformational change upon aa-tRNA release.
The Kluyveromyces lactis γ-toxin targets tRNA anticodons
Authors: LU JIAN , HUANG BO , ESBERG ANDERS , JOHANSSON MARCUS J.O. , BYSTRÖM ANDERS S.
Published: October 2005

Kluyveromyces lactis killer strains secrete a heterotrimeric toxin (zymocin), which causes an irreversible growth arrest of sensitive yeast cells. Despite many efforts, the target(s) of the cytotoxic γ-subunit of zymocin has remained elusive. Here we show that three tRNA species tRNAGlumcm5s2UUC, tRNALysmcm5s2UUU, and tRNAGlnmcm5s2UUG are the targets of γ-toxin. The toxin inhibits growth by cleaving these tRNAs at the 3′ side of the modified wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U). Transfer RNA lacking a part of or the entire mcm5 group is inefficiently cleaved by γ-toxin, explaining the γ-toxin resistance of the modification-deficient trm9, elp1-elp6, and kti11-kti13 mutants. The K. lactis γ-toxin is the first eukaryotic toxin shown to target tRNA.
Incidence of infection with the use of non-irradiated morcellised allograft bone washed at the time of revision arthroplasty of the hip
Authors: Kwong F. N. K. , Ibrahim T. , Power R. A.
Published: October 2005

Implantation of allograft bone is an integral part of revision surgery of the hip. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing allograft bone in order to reduce this risk. One method requires washing the tissue using pulsed irrigation immediately before implantation. We report the incidence of deep bacterial infection in 138 patients (144 revision hip arthroplasties) who had undergone implantation of allograft bone. The bone used was fresh-frozen, non-irradiated and pulse-washed with normal saline before implantation. The deep infection rate at a minimum follow-up of one year was 0.7%. This method of processing appears to be associated with a very low risk of allograft-related bacterial infection.
Blood loss after total knee replacement
Authors: Kalairajah Y. , Simpson D. , Cossey A. J. , Verrall G. M. , Spriggins A. J.
Published: October 2005

We carried out a prospective randomised study to evaluate the blood loss in 60 patients having a total knee arthroplasty and divided randomly into two equal groups, one having a computer-assisted procedure and the other a standard operation. The surgery was carried out by a single surgeon at one institution using a uniform approach. The only variable in the groups was the use of intramedullary femoral and tibial alignment jigs in the standard group and single tracker pins of the imageless navigation system in the tibia and femur in the navigated group.

The mean drainage of blood was 1351 ml (715 to 2890; 95% confidence interval (CI) 1183 to 1518) in the computer-aided group and 1747 ml (1100 to 3030; CI 1581 to 1912) in the conventional group. This difference was statistically significant (p = 0.001). The mean calculated loss of haemoglobin was 36 g/dl in the navigated group versus 53 g/dl in the conventional group; this was significant at p < 0.00001.

There was a highly significant reduction in blood drainage and the calculated Hb loss between the computer-assisted and the conventional techniques. This allows the ordering of less blood before the operation, reduces risks at transfusion and gives financial saving. Computer-assisted surgery may also be useful for patients in whom blood products are not acceptable.
Surgical treatment and outcome of conventional pelvic chondrosarcoma
Authors: Donati D. , Ghoneimy A. El , Bertoni F. , Di Bella C. , Mercuri M.
Published: October 2005

We reviewed 124 patients with a conventional pelvic chondrosarcoma who had been treated over a period of 20 years. We recorded the type of tumour (central or peripheral), type of operation (limb salvage surgery or hemipelvectomy), the grade of tumour, local recurrence and/or metastases, in order to identify the factors which might influence survival.

More satisfactory surgical margins were achieved for central tumours or in those patients treated by hemipelvectomy. However, grade 1 tumours, whatever the course, did not develope metastases or cause death, while grade 3 tumours had the worst outcome and prognosis.

Central, high-grade tumours require aggressive surgical treatment in order to achieve adequate surgical margins, particularly in those lesions located close to the sacroiliac joint. By contrast, grade 1 peripheral chondrosarcomas may be treated with contaminated margins in order to reduce operative morbidity, but without reducing survival.
Effect of Vitamin A on Fracture Risk
Authors: Jackson Heather A , Sheehan Amy Heck
Published: October 2005

OBJECTIVE

To describe current data evaluating the effect of vitamin A intake on fracture risk.

DATA SOURCES

A literature search using MEDLINE (1966–March 2005) was conducted using the search terms bone density, fractures, osteoporosis, retinol, and vitamin A to identify published studies evaluating the effects of vitamin A on bone.

DATA SYNTHESIS

Studies evaluating vitamin A consumption and fracture risk were reviewed. Current data suggest a potential inverse relationship between excess vitamin A consumption and bone mineral density leading to an increased risk for fracture.

CONCLUSIONS

Although current data are limited, consumption of large amounts of vitamin A may be associated with decreased bone mineral density and increased fracture risk. Until further information is available, patients should be made aware of the potential risks of consuming vitamin A in amounts that exceed the recommended dietary allowance. Further research is needed to clarify the relationship between vitamin A and fracture risk.
Efaproxiral: A Radiation Enhancer Used in Brain Metastases from Breast Cancer
Authors: Charpentier Margaret M
Published: October 2005

OBJECTIVE

To review the mechanism of action and clinical data of efaproxiral use in brain metastases of breast cancer.

DATA SOURCES

Articles were identified through MEDLINE (1966–June 2005) and EMBASE (1980–May 2005) searches using the key words efaproxiral and RSR13. Published abstracts over the previous 10 years from various scientific meetings, including American Society of Clinical Oncology and San Antonio Breast Cancer Symposium, were also searched for investigations of efaproxiral. Data on efaproxiral were also provided by Allos Therapeutics.

STUDY SELECTION AND DATA EXTRACTION

All published clinical data in humans regarding efaproxiral use in brain metastases from breast cancer were selected for this review. In addition, published studies in humans that discussed the pharmacokinetics, pharmacodynamics, and safety of efaproxiral were evaluated.

DATA SYNTHESIS

Efaproxiral is a synthetic allosteric modifier of hemoglobin that results in a shift of the hemoglobin oxygen dissociation curve to the right. Therefore, oxygen is more readily released from hemoglobin into tissues. Efaproxiral demonstrated a significant survival benefit when used as a radiation enhancer in patients with brain metastases originating from breast cancer. The safety profile of efaproxiral and improved survival rates make this agent advantageous over radiation alone. Further investigation and results from the ongoing clinical trials will help to define the role of efaproxiral in clinical practice.

CONCLUSIONS

Efaproxiral is the first synthetic allosteric modifier to demonstrate significant improvement in survival in patients undergoing radiation therapy for brain metastases of breast cancer. Validation of this effect in ongoing clinical trials will be important in determining the role of efaproxiral in brain metastases from breast cancer.
Holotranscobalamin and Total Transcobalamin in Human Plasma: Determination, Determinants, and Reference Values in Healthy Adults
Authors: Refsum Helga , Johnston Carole , Guttormsen Anne Berit , Nexo Ebba
Published: October 2005

Background: We developed microbiological assays (MBAs) to identify determinants and to establish reference values for cobalamin bound to transcobalamin [holotranscobalamin (holoTC)] and total TC in plasma.

Methods: We captured holoTC with magnetic beads with TC antibodies and used a conventional MBA for cobalamin measurements. Total TC was determined as holoTC after TC was saturated with cyanocobalamin. The new assays were compared with published methods. Determinants and reference values were determined in 500 blood donors, ages 18–69 years.

Results: Determination of cobalamin, holoTC, and TC by MBA required <150 μL. HoloTC and TC by MBA correlated with holoTC by RIA (r = 0.95) and TC by ELISA (r = 0.79), respectively. Between-day CVs for holoTC and total TC were 4%–9%. Women had lower holoTC than men, but only at age ≤45 years. In multivariate regression analyses, holoTC was positively associated with age (in women only), creatinine (in men only), and plasma concentrations of total TC, folate, and cysteine, but inversely correlated with homocysteine and methylmalonic acid. For all study participants, total TC was associated with holoTC and number of TCN2 766C alleles; in female participants only, total TC was also associated with age, homocysteine, and cysteine. Reference values were 670–1270 pmol/L for TC and 42–157 pmol/L for holoTC, but they differed according to age and sex.

Conclusions: Our MBAs for TC and holoTC required low plasma volume and performed acceptably compared with other methods. Determinants of holoTC and TC differed between men and women and according to age. Separate reference intervals for holoTC should be considered in younger women.
Transgenic Expression of a Dominant-Negative ASIC3 Subunit Leads to Increased Sensitivity to Mechanical and Inflammatory Stimuli
Authors: Mogil Jeffrey S. , Breese Nicole M. , Witty Marie-France , Ritchie Jennifer , Rainville Marie-Line , Ase Ariel , Abbadi Naima , Stucky Cheryl L. , Séguéla Philippe
Published: October 2005

Molecular and behavioral evidence suggests that acid-sensing ion channels (ASICs) contribute to pain processing, but an understanding of their precise role remains elusive. Existing ASIC knock-out mouse experiments are complicated by the heteromultimerization of ASIC subunits. Therefore, we have generated transgenic mice that express a dominant-negative form of the ASIC3 subunit that inactivates all native neuronal ASIC-like currents by oligomerization. Using whole-cell patch-clamp recordings, we examined the response properties of acutely isolated dorsal root ganglion neurons to protons (pH 5.0). We found that whereas 33% of the proton-responsive neurons from wild-type mice exhibited an ASIC-like transient response, none of the neurons from the transgenic mice exhibited a transient inward current. Capsaicin-evoked responses mediated by the TRPV1 receptor were unaltered in transgenic mice. Adult male wild-type and transgenic mice were subjected to a battery of behavioral nociceptive assays, including tests of thermal, mechanical, chemical/inflammatory, and muscle pain. The two genotypes were equally sensitive to thermal pain and to thermal hypersensitivity after inflammation. Compared with wild types, however, transgenic mice were more sensitive to a number of modalities, including mechanical pain (von Frey test, tail-clip test), chemical/inflammatory pain (formalin test, 0.6% acetic acid writhing test), mechanical hypersensitivity after zymosan inflammation, and mechanical hypersensitivity after intramuscular injection of hypotonic saline. These data reinforce the hypothesis that ASICs are involved in both mechanical and inflammatory pain, although the increased sensitivity of transgenic mice renders it unlikely that they are direct transducers of nociceptive stimuli.
The p75 Neurotrophin Receptor Negatively Modulates Dendrite Complexity and Spine Density in Hippocampal Neurons
Authors: Zagrebelsky Marta , Holz Andreas , Dechant Georg , Barde Yves-Alain , Bonhoeffer Tobias , Korte Martin
Published: October 2005

The correlation between functional and structural neuronal plasticity is by now well documented. However, the molecular mechanisms translating patterns of neuronal activity into specific changes in the structure of neurons remain unclear. Neurotrophins can be released in an activity-dependent manner, and they are capable of controlling both neuronal morphology and functional synaptic changes. They are thus attractive molecules to be studied in the context of synaptic plasticity. In the CNS, most of the work so far has focused on the role of BDNF and of its tyrosine kinase B receptor (TrkB), but relatively little is known about the function of the pan-neurotrophin receptor p75NTR. In this study, we show in loss-of-function experiments that postnatal hippocampal pyramidal cells in two mutant lines ofp75NTRhave a higher spine density and greater dendritic complexity than wild-type (WT) mice. Conversely, in a gain-of-function approach,p75NTRoverexpression in WT neurons significantly reduces dendritic complexity, as well as spine density in all dendritic compartments. These results show that p75NTRnegatively modulates dendritic morphology in adult hippocampal pyramidal neurons and documents a new case of functional antagonism between Trk and p75NTRsignaling.
In VivoMagnetic Resonance Microimaging of Individual Amyloid Plaques in Alzheimer's Transgenic Mice
Authors: Jack Clifford R. , Wengenack Thomas M. , Reyes Denise A. , Garwood Michael , Curran Geoffrey L. , Borowski Bret J. , Lin Joseph , Preboske Gregory M. , Holasek Silvina S. , Adriany Gregor , Poduslo Joseph F.
Published: October 2005

The ability to detect individual Alzheimer's amyloid plaquesin vivoby magnetic resonance microimaging (MRI) should improve diagnosis and also accelerate discovery of effective therapeutic agents for Alzheimer's disease (AD). Here, we performin vivoandex vivoMRI on double transgenic AD mice as well as wild-type mice at varying ages and correlate these with thioflavin-S and iron staining histology. Quantitative counts of individual plaques on MRI increase with age and correlate with histologically determined plaque burden. Plaques 20 μm in diameter can be detected in AD mice as young as 3 months of age withex vivoMRI. Plaques 35 μm in diameter can be detected by 9 months of age within vivoMRI.In vivoMRI of individual Alzheimer's amyloid plaques provides a noninvasive estimate of plaque burden in transgenic AD mice that might be useful in assessing the efficacy of amyloid reduction therapies.
Regulation of Kv7 (KCNQ) K+Channel Open Probability by Phosphatidylinositol 4,5-Bisphosphate
Authors: Li Yang , Gamper Nikita , Hilgemann Donald W. , Shapiro Mark S.
Published: October 2005

Voltage-gated Kv7 (KCNQ) channels underlie important K+currents, including the neuronal M current, and are thought to be sensitive to membrane phosphatidylinositol 4,5-bisphosphate (PIP2) and PIP2depletion to underlie muscarinic receptor inhibition. We studied regulation of Kv7.2-7.4 channels by PIP2in Chinese hamster ovary (CHO) cells using single-channel and whole-cell patch clamp and biochemical analysis. Maximal open probabilities (Po) of Kv7.2-Kv7.4 homomultimers and of Kv7.2/7.3 heteromultimers were found to be strongly dependent on the [diC8-PIP2] applied to inside-out patches, with differential apparent affinities that correlate with their maximalPoin on-cell mode. Unitary conductance was not affected by PIP2. Raising tonic [PIP2] by coexpression of phosphatidylinositol (4)5-kinase increased the maximalPoof both Kv7.2 and Kv7.2/7.3 channels studied in on-cell patches and increased whole-cell Kv7.2, but not Kv7.3, current amplitudes. In cells coexpressed with muscarinic M1receptors, bath application of muscarinic agonist reduced the maximalPoof Kv7.2/7.3 channels isolated in on-cell patches. Coexpression of a PIP2sequestering construct moderately reduced whole-cell Kv7.2/7.3 currents, and coexpression of a construct containing a PIP2phosphatase nearly abolished them. Finally, biochemical analysis of anionic phospholipids in CHO cells stably expressing M1receptors shows that PIP2and PIP are nearly depleted 1 min after muscarinic stimulation, with an unexpected rebound after 10 min. These results strongly support the direct regulation of Kv7 channels by PIP2and its depletion as the mechanism of muscarinic suppression of M channels. Divergent apparent affinities of Kv7.2-7.4 channels for PIP2may underlie their highly differential maximalPoobserved in cell-attached patches.
α7 Neuronal Nicotinic Acetylcholine Receptors Are Negatively Regulated by Tyrosine Phosphorylation and Src-Family Kinases
Authors: Charpantier Eric , Wiesner Andreas , Huh Kyung-Hye , Ogier Roch , Hoda Jean-Charles , Allaman Geraldine , Raggenbass Mario , Feuerbach Dominik , Bertrand Daniel , Fuhrer Christian
Published: October 2005

Nicotine, a component of tobacco, is highly addictive but possesses beneficial properties such as cognitive improvements and memory maintenance. Involved in these processes is the neuronal nicotinic acetylcholine receptor (nAChR) α7, whose activation triggers depolarization, intracellular signaling cascades, and synaptic plasticity underlying addiction and cognition. It is therefore important to investigate intracellular mechanisms by which a cell regulates α7 nAChR activity. We have examined the role of phosphorylation by combining molecular biology, biochemistry, and electrophysiology in SH-SY5Y neuroblastoma cells,Xenopusoocytes, rat hippocampal interneurons, and neurons from the supraoptic nucleus, and we found tyrosine phosphorylation of α7 nAChRs. Tyrosine kinase inhibition by genistein decreased α7 nAChR phosphorylation but strongly increased acetylcholine-evoked currents, whereas tyrosine phosphatase inhibition by pervanadate produced opposite effects. Src-family kinases (SFKs) directly interacted with the cytoplasmic loop of α7 nAChRs and phosphorylated the receptors at the plasma membrane. SFK inhibition by PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine] or SU6656 (2,3-dihydro-N,N-dimethyl-2-oxo-3-[(4,5,6,7-tetrahydro-1H-indol-2-yl)methylene]-1H-indole-5-sulfonamide) increased α7 nAChR-mediated responses, whereas expression of active Src reduced α7 nAChR activity. Mutant α7 nAChRs lacking cytoplasmic loop tyrosine residues because of alanine replacement of Tyr-386 and Tyr-442 were more active than wild-type receptors and insensitive to kinase or phosphatase inhibition. Because the amount of surface α7 receptors was not affected by kinase or phosphatase inhibitors, these data show that functional properties of α7 nAChRs depend on the tyrosine phosphorylation status of the receptor and are the result of a balance between SFKs and tyrosine phosphatases. These findings reveal novel regulatory mechanisms that may help to understand nicotinic receptor-dependent plasticity, addiction, and pathology.
What is the True Melting Point of Osmium?
Authors: Arblaster J. W.
Published: October 2005

It is proposed that 3400 ± 50 K is probably closer to the melting point of pure osmium than the value of 3300 K for impure metal which is usually quoted.
Tuned Out but Turned On: Boys' (Dis)engaged Reading In and Out of School
Authors: Cavazos‐Kottke Sean
Published: October 2005

The author reflects on contexts of language arts instruction that alienate boys from active engagement with academic literacy practices. He considers the impermeability of the language arts curriculum to students' vernacular literacy practices as a key factor in many boys' rejection of reading for academic purposes. Informed by experiences as a classroom teacher and a literacy researcher, the author shares the story of his own evolution from literature zealot to literacy consultant. He notes that as his classroom role changed to teacher as facilitator of individual students' literacy development, he observed many boys' re‐engagement with reading as they saw increasing convergence between reading for academic and for recreational purposes in their literacy lives.
Reading Comprehension Strategies for Adult Literacy Outcomes
Authors: Hock Mike , Mellard Daryl
Published: October 2005

This study extends the knowledge garnered from work with younger populations to determine the reading comprehension strategies most important to adults' success on outcome measures and to align them with previously researched interventions. According to an analysis of competence‐based standardized tests of literacy (such as the General Educational Development and the National Assessment of Educational Progress tests), adults should benefit from strategies that teach looking for clues in or generating questions about a text. In addition, adults need to learn how to summarize and draw inferences in order to address higher level literacy demands, and to use metacognitive strategies to self‐regulate reading behavior. Furthermore, if they must take competence‐based standardized tests, adult learners need to be taught test‐taking skills to reduce test‐related task demands. Test results will then produce a better index of adult learners' reading comprehension skills.
Hematologic Safety and Tolerability of Topotecan in Recurrent Ovarian Cancer and Small Cell Lung Cancer: An Integrated Analysis
Authors: Armstrong Deborah K. , Spriggs David , Levin Jeremey , Poulin Ruth , Lane Stephen
Published: October 2005

Learning Objectives

After completing this course, the reader will be able to: Explain the approved indications and treatment schedules for topotecan.Describe the typical pattern of hematologic toxicity during treatment with topotecan.Identify patients who are at higher risk for severe hematologic toxicity during treatment with topotecan.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

The purpose was to conduct an integrated analysis of the cumulative hematologic toxicity of topotecan in patients with relapsed ovarian cancer and small cell lung cancer (SCLC). Data were pooled from eight phase II and phase III clinical studies performed in patients with relapsed stage III/IV ovarian cancer or extensive SCLC treated with topotecan at a dose of 1.5 mg/m2 per day on days 1–5 of a 21-day course. Quantitative hematologic toxicities were assessed using the National Cancer Institute Common Toxicity Criteria. A total of 4,124 courses of therapy was administered to the 879 patients in the pooled population. Grade 4 neutropenia was experienced by 78% of patients. The lowest nadirs for neutrophils and platelets generally occurred after the first course of therapy, followed by improvement or stabilization in subsequent courses. Neutropenia was noncumulative. During the first course, significant risk factors were identified: renal impairment and advanced age (grade 3/4 thrombocytopenia and grade 4 neutropenia) and prior radiotherapy; performance status score ≥2; SCLC; and exposure to both cisplatin (Platinol®; Bristol-Myers Squibb, Princeton, NJ, http://www.bms.com) and carboplatin (Paraplatin®; Bristol-Myers Squibb) (grade 3/4 thrombocytopenia only). The most frequent interventions for hematologic toxicities were RBC transfusions, treatment delays, G-CSF support, and dose reductions. Analysis of neutrophil and platelet nadirs and dosing for each course of therapy showed no apparent evidence of cumulative neutropenia or thrombocytopenia. The risk of grade 3 or 4 anemia was higher during the first four courses of therapy and may need to be more aggressively managed with erythropoietin therapy.
Management of Cancer-Related Anemia in Patients with Breast or Gynecologic Cancer: New Insights Based on Results from the European Cancer Anemia Survey
Authors: Barrett-Lee Peter , Bokemeyer Carsten , Gascón Pere , Nortier J.W.R. , Schneider Maurice , Schrijvers Dirk , Van Belle Simon ,   Ecas Advisory Board and Participating Centers
Published: October 2005

Learning Objectives

After completing this course, the reader will be able to: Discuss the negative impact of anemia and its sequelae, particularly fatigue, in patients with breast or gynecologic cancer.Describe the results of the European Cancer Anemia Survey (ECAS), which defined the prevalence, incidence, and treatment of anemia in the European cancer community, identified anemia risk factors, and demonstrated that anemia is often suboptimally treated.Explain how the successful management of anemia is associated with patient well-being and improved overall quality of life.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

The incidence, prevalence, and treatment of anemia (hemoglobin [Hb] <12 g/dl) in women with breast cancer and gynecologic cancer were evaluated using data from the European Cancer Anemia Survey (ECAS). Adult patients with newly diagnosed treated or untreated disease, persistent/recurrent disease, and disease in remission were enrolled and followed for up to six chemotherapy cycles or six evaluation points within a 6-month period. At enrollment, 30.4% of breast cancer patients and 49.1% of gynecologic cancer patients were anemic. A significant correlation was shown between low Hb level and poor performance status (World Health Organization criteria) at enrollment for both breast cancer and gynecologic cancer patients. In all, 62.4% of breast cancer patients and 81.4% of gynecologic cancer patients were anemic at some time during the survey. The incidence of anemia, determined in a carefully defined population, was 59.8% for breast cancer patients and 74.8% for gynecologic cancer patients. Despite the high prevalence and incidence of anemia, only 26.3% and 42.7% of patients in the respective groups received anemia treatment. In breast cancer patients, the mean Hb trigger was 10 g/dl for epoetin treatment and 8.6 g/dl for transfusion; corresponding values for gynecologic cancer patients were 10.1 g/dl and 9.1 g/dl. Logistic regression analyses in the overall ECAS population identified five factors as significant and suitable predictors of anemia: lower initial Hb, having lung or gynecologic cancer versus gastrointestinal/colorectal cancer, any other cancer versus gastrointestinal/colorectal cancer, treatment with platinum chemotherapy, and being female. The ECAS data highlight the need for greater awareness of the adverse impact of anemia on cancer patients and for optimal anemia management to ensure maximal patient quality of life.
Thermal-creep analysis of concrete bridges
Authors: Xu Q. , Burgoyne C.
Published: October 2005

The creep effects on sequentially built bridges are analysed by the theory of thermal creep. Two types of analysis are used: time dependent and steady state. The traditional uniform creep analysis is also introduced briefly. Both simplified and parabolic normalising creep–temperature functions are used in the analysis for comparison. Numerical examples are presented, calculated by a computer program based on the theory of thermal creep and using the displacement method. It is concluded that different assumptions within thermal creep can lead to very different results when compared with uniform creep analysis. The steady-state analysis of monolithically built structures can serve as a limit to evaluate total creep effects for both monolithically and sequentially built structures. The importance of the correct selection of the normalising creep–temperature function is demonstrated.
Nuclear fission: continuing evolution of a future generation
Authors: Dagnall Stuart
Published: October 2005

There are nearly 450 operational nuclear fission reactors around the world, providing 16% of the world's electricity and cutting CO2 emissions by one billion tonnes a year. Britain's 23 operational reactors at 12 nuclear power stations provide over 20% of the country's electricity, though all but four will close within 10 years. This paper reviews the current state of the nuclear power industry and reports on the new generations of fission reactor design currently being researched and developed. It concludes that the future of electricity generation from nuclear fission in the UK lies in the deployment of an evolutionary ‘Generation III’ design to replace the current fleet of reactors, and for further research into revolutionary ‘Generation IV’ reactors.
Solar photovoltaic energy: generation in the built environment
Authors: Bahaj AbuBakr
Published: October 2005

Compared to other renewable energy technologies, modular solar photovoltaic technologies that convert sunlight into electricity and can generate power from watts to megawatts are more versatile and can be integrated within building envelopes. The cornerstone of the technology is the solar cell, which is manufactured from various semiconductor materials including silicon. Conversion efficiencies and costs have improved significantly in recent years and there are now many national schemes and energy targets promoting the use of photovoltaic technology in the built environment. This paper describes the current state of solar photovoltaic technology and the approaches being considered for using it to generate electricity within buildings.
Applications of Liquid-Solid Fluidization
Authors: Epstein Norman
Published: October 2005

Liquid fluidization of particulate solids has a history which predates the now more commonly applied gas fluidization. The broad range of operations to which liquid fluidization has found applications are summarized in this paper. These include classification of particles by size and density, a special case being sink-and-float separation by density; backwashing of granular filters and washing of soils; crystal growth; leaching and washing; adsorption and ion exchange; electrolysis with both inert and electrically conducting fluidized particles; liquid-fluidized bed heat exchangers and thermal energy storage; and bioreactors. Fluidized-bed bioreactors, which have received much attention during the past thirty years, are usually characterized by the catalytic use of enzymes or microbial cells that are immobilized by attachment, entrapment, encapsulation or self-aggregation. The most common application of such bioreactors is probably in wastewater treatment and, as in the case of the other operations mentioned above, liquid fluidization must in each case be weighed against competing schemes for achieving the same objective before it is adopted commercially.
Diffusion Resistances and Contribution of Surface Diffusion in TAME and TAEE Production Using Amberlyst-15
Authors: Dogu Timur , Aydin Ebru , Boz Nezahat , Murtezaoglu Kirali , Dogu Gulsen
Published: October 2005

Effective diffusivities and adsorption equilibrium constants of methanol, ethanol and 2-methyl-2-butene (2M2B), in Amberlyst 15, were evaluated from batch adsorption experiments. Moment expressions derived for different models involving diffusion resistances in the macropores and within the gel-like micrograins were used for the evaluation of effective diffusion coefficients. Contribution of surface diffusion to diffusion flux within the macropores was found to be quite significant. Also, it was found that diffusion resistance in liquid filled macropores was much more significant than diffusion resistance within the gel-like micrograins of Amberlyst 15., for methanol, ethanol and 2M2B.
Radial Distribution of Liquid Velocity in a Liquid-Solids Circulating Fluidized Bed
Authors: Zheng Ying , Zhu Jesse
Published: October 2005

Local liquid velocity was measured in a liquid-solid circulating fluidized bed, with a Plexiglas riser column of 7.62 cm ID and 3.0 m in height, by a dual conductivity probe, with 508 micron glass beads. The results show that radial distribution of local liquid velocity in the LSCFB is nonuniform with higher liquid velocity at the axis and lower near the wall, compared to the more uniform radial profiles in both the conventional fluidization and the dilute liquid transport regimes. The radial nonuniformity increases with increasing liquid velocity and solids circulation rate in the LSCFB. A radial nonuniformity index, proposed by Zhu and Manyele (2001), was used to quantify the extent of the radial nonuniformity under different solids circulation rates and liquid flow rates. The radial nonuniformity index is used to qualify the radial distribution of liquid velocity. RNI values in the liquid-solid circulating fluidization regime are seen to be much higher than those in both the particulate fluidization regime and the dilute liquid transport regime, indicating the nonuniform radial distribution of local liquid velocity in the LSCFB. This illustrates the use of RNI as an effective measurement of the radial distribution of liquid velocity.
Transport and Reaction Processes in Bioremediation of Organic Contaminants. 2. Role of Aggregate Size in Soil Remediation in a Slurry Bioreactor
Authors: Karimi Lotfabad Soheila , Gray Murray R
Published: October 2005

Transport processes in the soil matrix can control the rates of bioremediation of low-solubility contaminants. In this study, experiments were designed to test the hypothesis that diffusion of contaminants within soil aggregates of diameter 40 - 1000 micron was the limiting factor in bioremediation of creosote-contaminated soil. The concentrations of 6 different PAHs (acenaphthene, anthracene, chrysene, fluoranthene, phenanthrene, and pyrene) were monitored during the course of bioremediation of sonicated and non-sonicated soil by an active mixed culture in slurry bioreactors. Sonication of the soil to disperse soil aggregates increased the rate of microbial degradation up to 5 fold, however, there was no significant difference in the final residual concentrations between the two soil treatments. The aggregate size distribution after three weeks of treatment in a slurry bioreactor was comparable in both the sonicated and non-sonicated soils, which was consistent with the independence of the residual concentrations of PAHs on sonication treatment. The soil aggregates were modelled as porous materials, with pores filled with non-aqueous phase liquid and with films of non-aqueous phase liquid on particle surfaces. As the soil aggregates were dispersed, either by sonication or mixing, then the fraction of contaminants in exposed films increased. A diffusion-controlled mass transfer model was developed to represent release of PAHs from the soil, based on this physical model. The estimated diffusion coefficients of four of the PAHs (acenaphthene, phenanthrene, fluoranthene and pyrene ) in the residual creosote phase were in the range 4.4-4.8 x 10-14 cm2/s, while the diffusion coefficients for anthracene and chrysene were lower by a factor of 2. The similar values of diffusion coefficient between the components was consistent with release by diffusion through a viscous residual creosote. The magnitude of the diffusion coefficients was intermediate between the transport properties in high-viscosity oils, and polymers.