Home About us Contact
|
Home About us Contact | ||
|
|
||
Donors
Kinds of Donors Terms modified by Donors Selected AbstractsSPERM DONOR OR THWARTED FATHER?FAMILY COURT REVIEW, Issue 2 2009HOW WRITTEN AGREEMENT STATUTES ARE CHANGING THE WAY COURTS RESOLVE LEGAL PARENTAGE ISSUES IN ASSISTED REPRODUCTION CASES In recent years, the use of assisted reproduction has risen dramatically in the United States, allowing individuals who face various reproductive challenges, including infertility or absence of a heterosexual partner, to conceive biological children. While assisted reproduction has expanded to meet the needs of these parents, the legal system remains years behind, often leading to complicated child custody disputes between the parties. State legislatures have responded to the call for increased regulation of legal parentage in assisted reproduction in varying ways, although one popular statutory approach requires a known sperm provider to preserve his intention to parent in a written agreement with the woman. This article will argue that written agreement statutes are an effective means for resolving parentage disputes because of their ability to protect pre-insemination intent and encourage private ordering of conflicts among the parties. These issues will be explored through the lens of a recent case decided by the Kansas Supreme Court, In Re K.M.H., where the court enforced a written agreement statute against a sperm provider despite his equal protection and due process challenges. [source] ACUTE REJECTION IS MORE COMMON AND SEVERE IN LIVE DONOR THAN CADAVERIC DONOR KIDNEY TRANSPLANTSNEPHROLOGY, Issue 1 2002Johnson Dw [source] NOVEL SURVEILLANCE AND CURE OF A DONOR- TRANSMITTED LYMPHOMA IN A RENAL ALLOGRAFT RECIPIENTNEPHROLOGY, Issue 3 2000Herzig Ka [source] MYELINATION DEFICIT IN NERVE OF SUCKLING RATS DUE TO CYCLOLEUCINE -INDUCED DEFICIENCY OF METHYL DONORSJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000R. Bianchi We used cycloleucine (CL) , which prevents methionine conversion to S-adenosyl-methionine (SAMe) by inhibiting ATP-L-methionine-adenosyl-transferase (MAT) , to characterize the lipid and protein changes induced by methyl donors deficit in peripheral nerve and brain myelin in rats during development. We have previously shown that CL (400 mg/kg ip) given to suckling rats at days 7, 8, 12, and 13 after birth reduced brain and sciatic nerve weight gain, brain myelin content, protein, phospholipid (PL), and galactolipid concentration in comparison to control. Among PLs, only sphingomyelin (SPH) significantly increased by 35,50%. SAMe p-toluensulphonate (SAMe-SD4) (100 mg/kg, ip) given daily from day 7, as with exogenous SAMe, partially prevented some lipid alterations induced by CL, particularly galactolipid and SPH. To test the ability of CL to affect PL metabolism we have measured de novo PL biosynthesis, ex vivo in nerve homogenates (in comparison with brain homogenates) from control and CL-treated animals killed at day 18 after birth, starting from labelled substrates ([3H]-choline, specific activity 20 mCi/mmol) in a Tris/HCl buffer, containing 5 mM MgCl2, 0.2 mM EDTA, 0.1 mM ATP, and 0.5 mM of the labelled substrates. After 60 min incubation, lipids were extracted, PL separated by TLC, and corresponding silica gel fractions scraped and counted in a liquid scintillator. Phosphatidylcholine enrichment in labelled choline resulted in slight increases in brain and sciatic nerve of CL-treated rats, suggesting an increased synthesis rate via the Kennedy pathway, possibly due to the reduced availability of methyl donors. Interestingly, choline incorporation into SPH in brain and nerve myelin resulted in significant increases of 30,40%. In agreement with the observed decrease of galactolipid content and the relative increase in SPH, these data suggest an alteration in sphingolipid metabolism after CL. Among proteins, in sciatic nerves of CL-treated pups the relative content of a number of polypeptides, namely the 116, 90, 66, 58, and 56 kDa bands, decreased, whereas others increased; the most abundant PNS protein, protein zero, remained unchanged. The analyses of myelin basic protein isoforms revealed a dramatic increase in the 14.0 and 18.5 forms, indicating early active myelination. SAMe-SD4 treatment counteracted, and in some cases normalized, these changes. In summary, methyl donor deficiency induced by MAT inhibition produces myelin lipid and protein alterations, partly counteracted by SAMe-SD4 administration. The financial support of Telethon-Italy (grant No. D 51) is gratefully acknowledged. [source] RACIST ORGAN DONORS AND SAVING LIVESBIOETHICS, Issue 2 2007T.M. WILKINSON ABSTRACT This paper considers what should be done about offers of organs for transplant that come with racist strings attached. Saving lives or improving their quality seem powerful reasons to accept the offer. Fairness, justice, and rejecting racism seem like powerful reasons against. This paper argues that conditional allocation should occur when it would provide access to organs for at least one person without costing others their access to organs. The bulk of the paper concentrates on defending this claim against these objections: (i) that the good that might come about through conditional allocation does so through wrongful complicity in the racist's wrongdoing; (ii) that conditional allocation symbolizes support for racism; and (iii) that conditional allocation is unjust or unfair and is, for that reason, impermissible. The final section, on conditional allocation as a policy, considers the speculative possibility that conditional allocation would reduce access to organs for some, but it argues that, even then, conditional allocation could be justified. [source] Selective Tuning of the HOMO,LUMO Gap of Carbazole-Based Donor,Acceptor,Donor Compounds toward Different Emission ColorsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2010Huaqiang Zhang Abstract Carbazole-based donor,acceptor compounds with tunable HOMO,LUMO gaps were synthesized by Suzuki and Sonogashira cross-coupling reactions. Their optical and electrochemical properties were fully characterized. The results show that materials with different emission colors ranging from blue to green to orange could be obtained. The experimental results were also supported by theoretical calculations. [source] A Novel Bis(zinc,porphyrin),Oxoporphyrinogen Donor,Acceptor Triad: Synthesis, Electrochemical, Computational and Photochemical StudiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2006Jonathan P. Hill Abstract The first example of a porphyrin-quinonoid donor,acceptor triad featuring (tetraphenylporphinato)zinc(II) moieties covalently attached to an oxoporphyrinogen through its macrocyclic nitrogen atoms is reported. This arrangement of chromophores results in an interesting interplay between the electron-donating zinc,porphyrin(s) and the electron/energy accepting oxoporphyrinogen. The optical absorption of the triad reveals features corresponding to both the donor and acceptor entities. The geometry and electronic structure of the triad deduced from B3LYP/3-21G(*) calculations reveal an absence of inter-chromophoric interactions and localization of the HOMO on one zinc,porphyrin group and the LUMO on the oxoporphyrinogen scaffold. The electrochemical redox states of the triad were established from a comparative electrochemistry of the triad and the reference compounds. Both steady-state and time-resolved emission studies revealed quenching of the singlet excited state of zinc,porphyrin in the triad, and the free-energy calculations performed using Weller's approach indicate the possibility of electron transfer from the singlet excited zinc,porphyrin group to the oxoporphyrinogen in polar solvents. Time-resolved fluorescence studies reveal excited state energy transfer from zinc,porphyrin to oxoporphyrinogen in nonpolar solvents, while nanosecond transient absorption studies combined with time-resolved fluorescence studies in polar solvents are indicative of the occurrence of photoinduced charge separation from the singlet excited zinc,porphyrin to the oxoporphyrinogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthesis, Morphology, and Properties of Poly(3-hexylthiophene)- block -Poly(vinylphenyl oxadiazole) Donor,Acceptor Rod,Coil Block Copolymers and Their Memory Device ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yi-Kai Fang Abstract Novel donor,acceptor rod,coil diblock copolymers of regioregular poly(3-hexylthiophene) (P3HT)- block -poly(2-phenyl-5-(4-vinylphenyl)-1,3,4-oxadiaz-ole) (POXD) are successfully synthesized by the combination of a modified Grignard metathesis reaction (GRIM) and atom transfer radical polymerization (ATRP). The effects of the block ratios of the P3HT donor and POXD pendant acceptor blocks on the morphology, field effect transistor mobility, and memory device characteristics are explored. The TEM, SAXS, WAXS, and AFM results suggest that the coil block fraction significantly affects the chain packing of the P3HT block and depresses its crystallinity. The optical absorption spectra indicate that the intramolecular charge transfer between the main chain P3HT donor and the side chain POXD acceptor is relatively weak and the level of order of P3HT chains is reduced by the incorporation of the POXD acceptor. The field effect transistor (FET) hole mobility of the system exhibits a similar trend on the optical properties, which are also decreased with the reduced ordered P3HT crystallinity. The low-lying highest occupied molecular orbital (HOMO) energy level (,6.08 eV) of POXD is employed as charge trap for the electrical switching memory devices. P3HT- b -POXD exhibits a non-volatile bistable memory or insulator behavior depending on the P3HT/POXD block ratio and the resulting morphology. The ITO/P3HT44 - b - POXD18/Al memory device shows a non-volatile switching characteristic with negative differential resistance (NDR) effect due to the charge trapped POXD block. These experimental results provide the new strategies for the design of donor-acceptor rod-coil block copolymers for controlling morphology and physical properties as well as advanced memory device applications. [source] Donor and acceptor substrate selectivity among plant glycoside hydrolase family 32 enzymesFEBS JOURNAL, Issue 20 2009Wim Van den Ende Plant family 32 glycoside hydrolase enzymes include hydrolases (cell wall invertases, fructan exohydrolases, vacuolar invertases) and fructosyltransferases. These enzymes are very similar at the molecular and structural levels but are functionally different. Understanding the basis of the functional diversity in this family is a challenging task. By combining structural and site-directed mutagenesis data, Asp239 in AtcwINV1 was identified as an amino acid critical for binding and stabilizing sucrose. Plant fructan exohydrolases lack such an Asp239 equivalent. Substitution of Asp239 led to the loss of invertase activity, while its introduction in fructan exohydrolases increased invertase activity. Some fructan exohydrolases are inhibited by sucrose. The difference between the inhibitor (fructan exohydrolase) and the substrate (invertase) binding configurations of sucrose can be explained by the different orientation of Trp82. Furthermore, the evolutionary hydrolase/transferase transition could be mimicked and the difference between S-type fructosyltransferases (sucrose as donor) and F-type fructosyltransferases (fructan as donor) could be unravelled. [source] Improving the ON/OFF Ratio and Reversibility of Recording by Rational Structural Arrangement of Donor,Acceptor MoleculesADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Ying Ma Abstract Organic molecules with donor,acceptor (D,A) structure are an important type of material for nanoelectronics and molecular electronics. The influence of the electron donor and acceptor units on the electrical function of materials is a worthy topic for the development of high-performance data storage. In this work, the effect of different D,A structures (namely D,,,A,,,D and A,,,D,,,A) on the electronic switching properties of triphenylamine-based molecules is investigated. Devices based on D,,,A,,,D molecules exhibit excellent write,read,erase characteristics with a high ON/OFF ratio of up to 106, while that based on A,,,D,,,A molecules exhibit irreversible switching behavior with an ON/OFF ratio of about (3.2,×,101),(1,×,103). Moreover, long retention time of the high conductance state and low threshold voltage are observed for the D,A switching materials. Accordingly, stable and reliable nanoscale data storage is achieved on the thin films of the D,A molecules by scanning tunneling microscopy. The influence of the arrangement of the D and A within the molecular backbone disclosed in this study will be of significance for improving the electronic switching properties (ON/OFF current ratio and reversibility) of new molecular systems, so as to achieve more efficient data storage through appropriate design strategies. [source] Customized Electronic Coupling in Self-Assembled Donor,Acceptor NanostructuresADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Dimas G. de Oteyza Abstract Charge transfer processes between donor,acceptor complexes and metallic electrodes are at the heart of novel organic optoelectronic devices such as solar cells. Here, a combined approach of surface-sensitive microscopy, synchrotron radiation spectroscopy, and state-of-the-art ab initio calculations is used to demonstrate the delicate balance that exists between intermolecular and molecule,substrate interactions, hybridization, and charge transfer in model donor,acceptor assemblies at metal-organic interfaces. It is shown that charge transfer and chemical properties of interfaces based on single component layers cannot be naively extrapolated to binary donor,acceptor assemblies. In particular, studying the self-assembly of supramolecular nanostructures on Cu(111), composed of fluorinated copper-phthalocyanines (F16CuPc) and diindenoperylene (DIP), it is found that, in reference to the associated single component layers, the donor (DIP) decouples electronically from the metal surface, while the acceptor (F16CuPc) suffers strong hybridization with the substrate. [source] The Energy of Charge-Transfer States in Electron Donor,Acceptor Blends: Insight into the Energy Losses in Organic Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Dirk Veldman Abstract Here, a general experimental method to determine the energy ECT of intermolecular charge-transfer (CT) states in electron donor,acceptor (D,A) blends from ground state absorption and electrochemical measurements is proposed. This CT energy is calibrated against the photon energy of maximum CT luminescence from selected D,A blends to correct for a constant Coulombic term. It is shown that ECT correlates linearly with the open-circuit voltage (Voc) of photovoltaic devices in D,A blends via eVoc,=,ECT,,,0.5,eV. Using the CT energy, it is found that photoinduced electron transfer (PET) from the lowest singlet excited state (S1 with energy Eg) in the blend to the CT state (S1,,,CT) occurs when Eg,,,ECT,>,0.1,eV. Additionally, it is shown that subsequent charge recombination from the CT state to the lowest triplet excited state (ET) of D or A (CT,,,T1) can occur when ECT,,,ET,>,0.1,eV. From these relations, it is concluded that in D,A blends optimized for photovoltaic action: i) the maximum attainable Voc is ultimately set by the optical band gap (eVoc,=,Eg,,,0.6,eV) and ii) the singlet,triplet energy gap should be ,EST,<,0.2,eV to prevent recombination to the triplet state. These favorable conditions have not yet been met in conjugated materials and set the stage for further developments in this area. [source] Design of Multilayered Nanostructures and Donor,Acceptor Interfaces in Solution-Processed Thin-Film Organic Solar Cells,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2008Hiroaki Benten Abstract Multilayered polymer thin-film solar cells have been fabricated by wet processes such as spin-coating and layer-by-layer deposition. Hole- and electron-transporting layers were prepared by spin-coating with poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate) (PEDOT:PSS) and fullerene (C60), respectively. The light-harvesting layer of poly-(p -phenylenevinylene) (PPV) was fabricated by layer-by-layer deposition of the PPV precursor cation and poly(sodium 4-styrenesulfonate) (PSS). The layer-by-layer technique enables us to control the layer thickness with nanometer precision and select the interfacial material at the donor,acceptor heterojunction. Optimizing the layered nanostructures, we obtained the best-performance device with a triple-layered structure of PEDOT:PSS|PPV|C60, where the thickness of the PPV layer was 11,nm, comparable to the diffusion length of the PPV singlet exciton. The external quantum efficiency spectrum was maximum (ca. 20%) around the absorption peak of PPV and the internal quantum efficiency was estimated to be as high as ca. 50% from a saturated photocurrent at a reverse bias of ,3,V. The power conversion efficiency of the triple-layer solar cell was 0.26% under AM1.5G simulated solar illumination with 100,mW,cm,2 in air. [source] Donor,Acceptor C60 -Containing Polyferrocenylsilanes: Synthesis, Characterization, and Applications in Photodiode Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2008Masato Nanjo Abstract A series of polyferrocenylsilane (PFS) random copolymers containing covalently bound pendant [C60]fullerene groups, the first well-characterized metallopolymers with pendant C60 units, have been prepared and characterized. The fullerene content of the prepared copolymers ranges from 7 to 24% relative to monomer unit. The desired copolymers were synthesized in three steps: metal-catalyzed ring opening polymerization of sila[1]ferrocenophanes was performed to synthesize random copolymers of poly(ferrocenylmethylphenylsilane -co- ferrocenylchloromethylsilane); the resulting random PFSs were then functionalized by reaction with 11-azido-1-undecanol to give PFSs with pendant azide groups; the desired donor,acceptor C60 -containing PFSs were then synthesized by the reaction of the azide group in the side chains with C60 in toluene at 110,°C. The resulting C60 -containing PFSs are air-stable and soluble in aromatic solvents, chloroform, or THF. The UV-vis spectra of these materials show broad absorption up to 800 nm. Thin films of these materials were examined as the active layer in rare examples of all solid-state sandwich-type diode devices based on ferrocene-fullerene dyads. The devices exhibit photoconducting and photovoltaic responses, with an open circuit potential of ca. 0.3 V under white light illumination. [source] A New Donor,Acceptor,Donor Polyfluorene Copolymer with Balanced Electron and Hole Mobility,ADVANCED FUNCTIONAL MATERIALS, Issue 18 2007A. Gadisa Abstract A new alternating polyfluorene copolymer poly[2,7-(9,9-dioctylfluoren)- alt -5,5-(5,,8,-di-2-thienyl-(2,,3,-bis-(3,,-octyloxyphenyl)-quinoxaline))] (APFO-15), which has electron donor,acceptor,donor units in between the fluorene units, is synthesized and characterized. This polymer has a strong absorption and emission in the visible range of the solar spectrum. Its electroluminescence and photoluminescence emissions extend from about 560 to 900 nm. Moreover, solar cells with efficiencies in excess of 3.5,% have been realized from blends of APFO-15 and an electron acceptor molecule, a methanofullerene [6,6]-phenyl-C61 -butyric acid methyl ester (PCBM). It has also been observed that electron and hole transport is balanced both in the pure polymer phase and in polymer/PCBM bulk heterojunction films, which makes this material quite attractive for applications in opto-electronic devices. [source] Analysis of free flap viability based on recipient vein selectionHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2009David O. Francis MD Abstract Background. Venous anastomotic failure is the primary reason for microvascular free tissue transfer failure. Donor and recipient veins can be oriented in the same longitudinal axis (end-to-end anastomosis), or the donor vein can be anastomosed to the internal jugular vein in an end-to-side configuration. No consensus on the optimal anastomosis configuration exists. We sought to evaluate whether type of venous anastomosis impacts flap survival rate. Methods. Data were collected on all patients undergoing microvascular free flap reconstruction of head and neck defects at the University of Washington between August 1993 and April 2007. Flaps with a single venous anastomosis were analyzed. Flaps were stratified into those with end-to-end and end-to-side anastomoses. Survival rates were compared between groups using bivariate and multivariate techniques. Results. Inclusion criteria were met by 786 free flaps; 87% performed in an end-to-end and 13% in an end-to-side configuration. Flap re-exploration and failure rate were 4.3% and 1.1%, respectively. In multivariate analysis, there was no difference in odds of flap re-exploration (OR .70, 95% CI .23,2.18) or flap failure whether or not an end-to-end or end-to-side anastomosis was performed (OR 2.09, 95% CI .38,11.5). Conclusions. In this large cohort of patients, we found no difference in the odds of flap re-exploration or failure based on venous anastomotic configuration. Reconstructive surgeons should have both anastomotic techniques in their repertoire to optimize the success of every flap. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source] Donor,Acceptor-Substituted Oligo(1,4-phenylene)sHELVETICA CHIMICA ACTA, Issue 6 2009Soungkyoo Kim Abstract Oligo(para -phenylene)s (DAOPPs) 2a,2d (n=1,4) with terminal donor,acceptor substitution (D=C6H13O, A=NO2) were prepared by applying Suzuki cross-couplings for chain extension and end capping. The push,pull effect induces short-reaching polarizations of the chain consisting of conjugated but twisted benzene rings, which was studied by NMR measurements. Electron excitation from the ground-state S0 to the more planar first-excited singlet state S1 is combined with a strong intramolecular charge transfer (ICT), which is documented by the red shift of the long-wavelength absorption (charge-transfer band) for short chains (one or two repeat units, n,=,1 or 2). The opposite influence of decreasing ICT and increasing conjugation length leads to a bathochromic series (,max(n+1),,max(n)) with a fast saturation of ,max (n). The effective conjugation length nECL=4 corresponds to ,, 349,nm. These results are discussed in the context of other oligo(para -phenylene)s (OPPs). [source] A Donor,Acceptor Polymer with a Peculiar Negative-Charge-"Trapping" Characteristic,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2003G. Casalbore-Miceli Abstract Voltammetric and spectrophotometric measurements of poly(3,3,-dipentoxy-3,-dicyanoethenyl-2,2,:5,,2,-terthiophene) (polyCN) films, in connection with other experimental evidence, reveal a normal oxidative, but a peculiar reductive behavior consisting of trapping of the negative charge during the cathodic scan. Another interesting property of polyCN films is the tendency to form strong intramolecular and intermolecular associations, probably charge-transfer (CT) complexes. These properties could account for the fact that the photovoltaic performance does not improve when polyCN is blended with a polythiophene donor. [source] Effect of Through-Bond Interaction on Conformation and Structure in Rod-Shaped Donor,Acceptor Systems.HELVETICA CHIMICA ACTA, Issue 3 2003Part The crystal structures of five N -arylpiperidin-4-one derivatives 2P2, 3P2, 5P2, 1P3, and 2P3 are presented (Fig.,2 and Tables,1,5) and discussed together with the derivatives 1P2 and 4P2 published previously. In all but one structure, 1P2, the aryl group is in an equatorial position. The piperidine ring adopts a normal chair conformation. In 1P2, the piperidine ring central CC bonds are significantly elongated, which is consistent with the idea that through-bond interaction is more pronounced in the axial conformation. Through-bond interaction also influences the pyramidalization at the piperidine C(4)-atom in such a way that a strong interaction is directing the ethylene C-atom C(9) into the axial direction. [source] Role of the Charge Transfer State in Organic Donor,Acceptor Solar CellsADVANCED MATERIALS, Issue 37 2010Carsten Deibel Charge transfer complexes are interfacial charge pairs residing at the donor,acceptor heterointerface in organic solar cell. Experimental evidence shows that it is crucial for the photovoltaic performance, as both photocurrent and open circuit voltage directly depend on it. For charge photogeneration, charge transfer complexes represent the intermediate but essential step between exciton dissotiation and charge extraction. Recombination of free charges to the ground state is via the bound charge transfer state before being lost to the ground state. In terms of the open circuit voltage, its maximum achievable value is determined by the energy of the charge transfer state. An important question is whether or not maximum photocurrent and maximum open circuit voltage can be achieved simultaneously. The impact of increasing the CT energy,in order to raise the open circuit voltage, but lowering the kinetic excess energy of the CT complexes at the same time,on the charge photogeneration will accordingly be discussed. Clearly, the fundamental understanding of the processes involving the charge transfer state is essential for an optimisation of the performance of organic solar cells. [source] Spray-Processable Blue-to-Highly Transmissive Switching Polymer Electrochromes via the Donor,Acceptor ApproachADVANCED MATERIALS, Issue 6 2010Chad M. Amb Spray processable blue electrochromic polymers with strictly alternating "donor-acceptor" copolymers are reported that exhibit saturated blue neutral states, highly transmissive oxidized states, excellent optical contrasts, fast switching times, and long-term redox switching stability. In addition, an alkylester-functionalized analogue is demonstrated, where the solubility of the material thin-film is irreversibly changed while allowing it to retain its electroactivity. [source] Organic Electronics: High-mobility Ambipolar Transistors and High-gain Inverters from a Donor,Acceptor Copolymer Semiconductor (Adv. Mater.ADVANCED MATERIALS, Issue 4 20104/2010) The cover illustrates a polymer semiconductor highway for efficient transport of both electrons and holes. On p. 478, Samson A. Jenekhe, Mark D. Watson, and co-workers have demonstrated high-mobility single-component ambipolar field-effect transistors, by utilizing a new polymer semiconductor, and integrated them into complementary inverters. Polymer semiconductors with good ambipolar charge transport provide a simpler way to realize complementary circuits and other devices and functions in organic electronics. [source] High-mobility Ambipolar Transistors and High-gain Inverters from a Donor,Acceptor Copolymer SemiconductorADVANCED MATERIALS, Issue 4 2010Felix Sunjoo Kim High-performance ambipolar transistors and inverters are demonstrated using a new donor,acceptor copolymer semiconductor. The ambipolar transistors show electron and hole mobilities of up to 0.04 and 0.003 cm2 V,1 s,1, respectively. Voltage transfer curves of the inverters made on common gold electrodes showed sharp switching with gain of 30. [source] Intramolecular Donor,Acceptor Regioregular Poly(hexylphenanthrenyl-imidazole thiophene) Exhibits Enhanced Hole Mobility for Heterojunction Solar Cell ApplicationsADVANCED MATERIALS, Issue 20 2009Yao-Te Chang PHPIT, a new kind of intramolecular donor,acceptor side-chain-tethered hexylphenanthrenyl-imidazole polythiophene is synthesized. The more-balanced electron and hole mobilities and the enhanced visible- and internal-light absorptions in the devices consisting of annealed PHPIT/PCBM blends both contribute to a much higher short-circuit current density, which in turn led to a power conversion efficiency as high as 4.1%. [source] Analysis of chimerism during the early period after allogeneic peripheral stem cell transplantationINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2001B. Gleissner As there are few reports on early evaluation of chimerism, we assessed fluorescence short tandem repeats (STR) by polymerase chain reaction (PCR) assays to analyse donor and recipient characteristics at early time points after peripheral stem cell transplantation (PBSCT). Peripheral blood of 13 patients was analysed in 1- to 2-day intervals starting from the day of PBSCT. Donor and recipient allelic patterns were determined by a commercially available multiplex STR assay that simultaneously evaluates four or five gene loci. Mixed chimerism appeared in all patients during days 1,9 after transplantation and preceded haematologic engraftment for 3,12 days. Even patients without myeloablative conditioning therapy (n=4) revealed donor allelic patterns within 1,5 days. Nine patients changed during the following days to a complete donor allelic pattern and had an uncomplicated post-transplant disease course. Four patients did not consistently retain complete donor chimerism; two of them relapsed within the next 3 months, one died from septicemia within 7 days, and the fourth, transplanted for aplastic anaemia, is still in complete remission. Overall, STR analysis using a simple and comparatively cheap multiplex system permits the detection of chimerism very early after transplantation and may provide relevant information that correlates with the clinical follow-up. [source] Cyanide-Catalyzed Additions of Acyl Phosphonates to Aldehydes: A New Acyl Donor for Benzoin-Type ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Abstract Acyl phosphonates have been utilized as new acyl donors for cyanide-catalyzed benzoin-type reactions. Cyanation of acyl phosphonates, followed by a [1,2]-phosphoryl migration generates the active acyl anion intermediate. The presumed (cyano)phosphate anion reacts with a variety of aryl aldehydes to yield phosphate ester-protected, unsymmetrical benzoins in good to excellent yields. The unsymmetrical benzoin product can be obtained after deprotection of the phosphate ester with an aqueous amine solution. [source] Effect of Donor, Acceptor, and Donor,Acceptor Codoping on the Electrical Properties of Ba0.6Sr0.4TiO3 Thin Films for Tunable Device ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2009Yuanyuan Zhang We have investigated the effects of donor, acceptor, and donor,acceptor codoping on both the dielectric properties and the leakage current behavior of Ba0.6Sr0.4TiO3 thin films prepared by the metalorganic solution deposition technique. La and Co were selected as donor and acceptor dopants, respectively. The electrical properties depend strongly on the type of dopants. Compared with others, codoped BST films have a much lower loss tangent, higher figure of merit, and lower leakage current. The electronic conduction mechanisms of the three types of dopants are reported. [source] Effect of the Liquid-Phase Characteristic on the Microstructures and Dielectric Properties of Donor- (Niobium) and Acceptor- (Magnesium) Doped Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2003Seok-Hyun Yoon Changes in the microstructure and dielectric properties with the variation of the donor/acceptor ratio in BaTiO3 ceramics were investigated. In donor-rich specimens, a liquid that appeared during sintering did not penetrate into grain boundaries. However, in the acceptor-rich specimens, the grains were separated by a liquid film during sintering. The much higher mobility of the liquid film than that of the grain boundaries was suggested to cause extensive grain growth in acceptor-rich BaTiO3. The macroscopic homogenization of dopants because of grain growth in acceptor-rich specimens resulted in changes in the dielectric properties. [source] Positive Temperature Coefficient of Resistivity Effect in Highly Donor,Doped Barium TitanateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2001Darko Makovec BaTiO3 ceramics doped with different La concentrations (0,12 mol%) were prepared by sintering under the reducing conditions of a nitrogen atmosphere containing 1% hydrogen. The critical donor concentration that causes blocking of the exaggerated grain growth was observed to be ,10 mol% La. The samples, which were semiconducting after sintering under reducing conditions, were subsequently reoxidized by annealing in air to induce the positive temperature coefficient of resistivity (PTCR) effect. After reoxidation at 1150°C a noticeable PTCR effect was observed in the samples doped with La concentrations as high as 2.5 mol%. The room-temperature resistivity after reoxidation was found to increase with increasing donor concentration due to an increase in the thickness of the insulating layers at the grain boundaries. TEM analysis showed that reoxidation of the samples caused precipitation of the Ti-rich compound Ba6Ti17O40 inside the doped BaTiO3 -matrix grains. [source] AASLD/ILTS transplant course: Is there an extended donor suitable for everyone?LIVER TRANSPLANTATION, Issue S2 2005Andrew Cameron Key Points 1The clinical success of liver transplantation coupled with the current era of organ shortage has caused many centers to expand their criteria for acceptable donors. 2The definition of "Extended Criteria Donor" (ECD) is becoming better understood and quantified. 3Recipient factors that portend poor outcome must be recognized and factored in as well. Grafts and recipients must be "matched" to manage and minimize the risk from ECDs. 4Maintaining acceptable outcomes as ECD concepts evolve is paramount. 5Absolute risk factors for poor graft function still exist and must be respected, but relative risk factors are now well identified, quantified, accepted, and managed as an alternative to high waiting list mortality. (Liver Transpl 2005;11:S2,S5.) [source] | |||||||||||||||||||||||||||||||||||||||||||||||||