bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and photophysical behavior of axially substituted phthalocyanine, tetrabenzotriazaporphyrin, and triazatetrabenzcorrole phosphorous complexes
Authors: Antunes Edith M. , Nyokong Tebello
Published: March 2009

The synthesis of phosphorous phthalocyanines, triazatetrabenzcorroles, and tetrabenzotriazaporphyrins with a variety of axial ligands is reported. The new complexes are: phosphorous dihydroxy tetrabenzotriazaporphyrin (5, PV(OH)2TBTAP), diphenyl phosphorous phthalocyanine (6, [PV(Ph)2Pc](OH)), diphenyl phosphorous triazatetrabenzcorrole (7, PV(Ph)2TBC), and dioctyl phosphorous triazatetrabenzcorrole (8, PV(C8H17)2TBC). The complexes are not aggregated in dimethylsulfoxide (DMSO) and pyridine. Upon axial coordination of a phenyl or octyl group, the complexes are soluble (and not aggregated) in dichloromethane (DCM) and tetrahydrofuran (THF). The triplet lifetimes range from 395 to 546 μs (for complexes 5 to 8), with the P(Ph)2TBC (7) complex showing the longest triplet lifetime (546 μs), while the smallest triplet quantum yield (ΦT= 0.27) was obtained for the [P(Ph)2Pc](OH) (6) complex. [P(OH)2Pc](OH) (3) showed the shortest triplet lifetime (113 μs) and the largest triplet quantum yield (ΦT= 0.52).
Bisporphyrin connected by tetrathiafulvalene
Authors: Ogawa Kazuya , Nagatsuka Yasunori
Published: March 2009

A new porphyrintetrathiafulvalene composite, where two porphyrins are bridged by te trathiafulvalene (TTF) using acetylene bonds was synthesized. The Q-band of the monomeric porphyrin appears at 590 nm whereas that of the composite is red-shifted to 620 nm and intensified. The Soret band is also red-shifted from 427 nm to 435 nm and much broadened, indicating the expansion of π-conjugation over the porphyrin and tetrathiafulvalene units. The HOMOs and LUMOs were calculated using time-dependent density functional theory. Voltammetric experiments revealed that the first oxidation potential of the TTF moiety in the composite was shifted by +155 mV compa red with TTF in the absence of composite. The effective two-photon absorption (2PA) cross section values were measured by using a nanosecond open aperture Z-scan method. The maximum effective 2PA cross section values were obtained at 760 nm, as 7300 GM in benzonitrile and 5900 GM in toluene. The values obtained in the polar solvent were 1.2 to 1.5 times larger than those in the nonpolar solvent.
Discotic liquid crystals of transition metal complexes 40: unique double-clearing behavior of a series of novel discotic metallomesogens based on bis(phthalocyaninato)europium(III) complexes
Authors: Mukai Hidetomo , Yokokawa Miho , Hatsusaka Kazuaki , Ohta Kazuchika
Published: March 2009

It has long been believed that the phase transition behavior and clearing points (c.p.s) of phthalocyanine-based metallomesogens scarcely change regardless of the kind of central metal. In this work, we have synthesized a series of novel sandwich-type, europium complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]europium(III) (abbreviated as {[( C n O )2 PhO ]8 Pc } 2 Eu (n = 8-16) (2a–2i)). Their mesomorphic properties were investigated by polarization microscope, differential scanning calorimeter and temperature dependent X-ray diffraction techniques to make a comparison with the phase transition behavior and c.p.s of the previously reported lutetium homologs ({[( C n O )2 PhO ]8 Pc }2 Lu (n = 8-16) (1). Very interestingly, the c.p.s of {[( C n O )2 PhO ]8 Pc }2 Eu complexes (2) are higher by 35–61°C than those of {[( C n O )2 PhO ]8 Pc }2 Lu complexes (1) having the same chain length (n). Furthermore, these Eu complexes (2) exhibited unique double-clearing behavior, whereas the Lu complexes (1) did not. For instance, the Eu complex (2i: n = 16) exhibited the following phase transition sequence: crystalline phase (K) 49°C Colh 133°C [Formula: see text] 158°C [Formula: see text] 216°C I.L.; the I.L. very slowly transformed into a Coltet mesophase; on further heating, Coltet cleared into I.L. again at 240°C. On the other hand, the corresponding Lu complex (1i: n = 16) exhibited a phase transition sequence of K 50°C Colh 124°C [Formula: see text] 148°C Coltet 205°C I.L., and did not exhibit the doubleclearing behavior. Thus, it was revealed for the first time, in the phthalocyanine-based metallomesogens, that the central metal had a large influence on their c.p.s and their phase transition behavior.
Synthesis of an amide-linked chlorin-anthraquinone dyad and its structural and spectroscopic properties
Authors: Könekamp Thorsten , Borrmann Tobias , Montforts Franz-Peter
Published: March 2009

An enantiomerically pure chlorin-anthraquinone dyad 6 was synthesized in respect to a model compound for light-induced electron transfer in the photosynthetic center. Therefore, the enantiomerically pure chlorin 4 was linked with the anthraquinone amine 5 to form a peptide-like dyad. The conformation of the dyad follows NMR investigations and a PM3 calculation. Observed quenching of the fluorescence indicates an intramolecular energy and/or electron transfer from the chlorin donor moiety to the anthraquinone subunit of the dyad.
Photoinduced electron transfer in supramolecular assemblies involving saddle-distorted porphyrins and phthalocyanines
Authors: Kojima Takahiko , Nakanishi Tatsuaki , Honda Tatsuhiko , Fukuzumi Shunichi
Published: March 2009

Unique supramolecular assemblies are constructed based on a saddle-distorted non-planar porphyrin, dodecaphenylporphyrin ( H2DPP ), and its metal complexes. The saddle distortion facilitates protonation of pyrrole nitrogens to afford a stable diprotonated porphyrin, which can act as an electron acceptor. A diprotonated hydrochloride salt of a saddle-distorted dodecaphenylporphyrin ([ H4DPP ] Cl2) forms a nano-sized channel structure called a "porphyrin nanochannel". Electron-donating molecules such as hydroquinones are included as guest molecules in the porphyrin nanochannel. Photoinduced electron transfer from the guest molecules to the singlet state of H4DPP2+occurs, producing H4DPP+•and cation radicals of the guest molecules. The saddle distortion also results in higher Lewis acidity at a metal center to maintain axial coordination of ligands, due to poor overlap of the lone-pair orbitals with the d orbitals of the metal center. By taking advantage of saddle distortion of both H4DPP2+and zinc phthalocyanine, 1,4,8,11,15,18,22,25-octaphenylphthalocyanine ( ZnOPPc ), a discrete supramolecular assembly composed of H4DPP2+and ZnOPPc , is obtained using 4-pyridinecarboxylate (4-PyCOO-) that connects the two components by hydrogen bonding and coordination bonding, respectively. Photoexcitation of the assembly results in efficient electron transfer from ZnOPPc to H4DPP2+in the supramolecular complex.
Electrical transduction in phthalocyanine-based gas sensors: from classical chemiresistors to new functional structures
Authors: Bouvet Marcel , Parra Vicente , Locatelli Clémentine , Xiong Hui
Published: March 2009

Phthalocyanines are organic-based materials which have attracted a lot of research in recent times. In the field of sensors, they present interesting and valuable potentialities as sensing elements for real gas sensor applications. In the present article, and taking some of our experiments as representative examples, we review the different ways of transduction applied to such applications. Some of the new tendencies and transducers for gas sensing based on phthalocyanine derivatives are also reported. Among them, electrical transduction (resistors, field-effect transistors, diodes, etc.) has been, historically, the most commonly exploited way for the detection and/or quantification of gas pollutants, vapors and aromas, according to the conducting behavior of phthalocyanines. We will focus precisely on these systems.
Solvent-induced supramolecular assemblies of crown-substituted ruthenium phthalocyaninate: morphology of assemblies and non-linear optical properties
Authors: Grishina Antonina D. , Gorbunova Yulia G. , Zolotarevsky Victor I. , Pereshivko Larisa Ya. , Enakieva Yulia Yu. , Krivenko Tatiana V. , Savelyev Vladimir , Vannikov Anatoly V. , Tsivadze Aslan Yu.
Published: March 2009

The information concerning the architecture of supramolecular assemblies, which are composed of ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated triethylenediamine molecules, has been obtained with the application of atomic force microscopy. The ensembles are formed in Ru ( II ) complex solutions in chloroform and tetrachloroethane. The number of molecules and their relative orientation in supramolecular assemblies were estimated in dependence of the solvent (chloroform, tetrachloroethane) and the heating temperature. Samples fabricated after heating of the Ru ( II ) complexes solution in tetrachloroethane formed stable supramolecular wires of 600 nm and more in length. The third-order non-linear optical characteristics of complexes in tetrachloroethane solution were studied by the z-scanning method. Molecular polarizability of the complex is about 4.5 × 10-32 esu. The polarizability attributed to one molecule increases by a factor of 3.6 when the individual molecule assembles into a supramolecular aggregate.
SELF-CONSISTENT FIELD MODELING OF THE NEUROFILAMENT NETWORK
Authors: LEERMAKERS F. A. M. , ZHULINA E. B.
Published: March 2009

We have investigated, on a self-consistent field level, the equilibrium structure of the neurofilament network formed by the NF -H, NF -M and NF -L proteins, using the one-gradient version of the numerical model of Scheutjens and Fleer. We demonstrate a reticulation of NFs in parallel bundles that occurs due to hydrophobic attractions between apolar aminoacid residues in the terminal parts of the M- and H-tails. We elaborate on the feasibility that the stability of the NF network can be enhanced by specific interactions between the projection domains, possibly induced by accessary proteins. We demonstrate that the phosphorylation of KSP repeats in the M- and H-tails promotes the cross-bridging between the NFs and therefore helps form the NF network.
CADMIUM AND PROTON NMR STUDY ON [Cd2(BIS(2-PYRIDYL)FORMAMINE)3]
Authors: LU HUNG-CHIEH , KAN LOU-SING
Published: March 2009

The structure of a bi - Cd organic complex [ Cd 2(bis(2-pyridyl)formamine)3 or 1], is analyzed thoroughly by 1 H and 113/111 Cd NMR in solution. Only one representative set of pyridyl proton resonance of a total of six pyridines in 1 was observed. The resonance of protons in pyridine ring can be assigned by both 2D COSY and 2D NOESY. Similarly, only one Cd (either 113 Cd or 111 Cd NMR signal was observed too. This indicates that the two Cd atoms in 1 are chemically equivalent. The Cd signal is split by its three neighboring equivalent protons on the bridged carbon atoms ( C a H )3, resulting in a quartet. The 3 J 113 Cd –1 H and 3 J 111 Cd –1 H are 44 and 42 Hz, respectively, measured directly from the spectral pattern. The proton NMR signals of C a H composed from three sources: (1) superimposed doublets arising from Cd – H –113 Cd and Cd – H –111 Cd ; (2) a pseudo triplet from 113 Cd – H –113 Cd , 111 Cd – H –111 Cd and 113 Cd – H –111 Cd and (3) a singlet from those H's surrounded by all non-magnetic Cd atoms. They superimpose and appear as a quintet with intensity ratio of 1:12:38:12:1, explainable by the above constituents and their associated Cd – H splitting analyses. We deduced that the three bis(2-pyridyl)formamidine groups have a three-fold symmetry with respect to the Cd – Cd axis, i.e., the three bis(2-pyridyl)formamidine units are co-planar and spaced 120 degrees from each other based on above observations. This implies the key C a atom exists as a hybrid of two canonical forms (– N = C a H – N – ↔ – N – C a H = N –). As a consequence, 1 does not exhibit chirality. We exemplified that Cd NMR study is well suited for investigating those metalloproteins if the calcium and/or zinc ions contained can be replaced by 113 Cd /111 Cd ions of similar size.
Carbon co-implantation Used to Improve NMOS Threshold Voltage Roll-off Characteristics Study in 65nm Node CMOS Technology
Authors: Liu Jinhua , Allan Zhou , Jianhua Ju , Dai Shugang , Shen Zhaoxu , Liu Eric , Wang Brisk , Hung Albert , Ho Hokmin , Ning Jay
Published: March 2009

Around 50mV RSCE and SCE improvement has been obtained by C co-implantation optimization in 65nm node CMOS technology. Besides this, gate to source/drain overlap capacitance (Cgd0) and junction capacitance (Cj) are seen to be reduced 6% and 11% respectively. C co-implantation before and after halo implantation are compared also, the result reveals that C co-implantation after halo implantation helps to improve NMOS drain induced barrier lowering (DIBL) features. Gate oxide leakage comparison for different C co-implantation conditions indicates that C co-implantation induces no gate oxide quality degradation.
Investigation into the Output Characteristics and Improvement of Operation Margin of IMOS (Impact Ionization MOS) Devices
Authors: Liu Huichu , Huang Ru , Wang Zhenhua
Published: March 2009

The output characteristics of typical Impact Ionization MOS (IMOS) devices is comprehensively investigated in this paper. The results show that IMOS devices exhibit a narrow operating margin with non-saturated on-current. To improve the output characteristics, a new structure named "pocket IMOS" is proposed. Compared with the typical I-MOS devices, the "pocket I-MOS" can achieve a wider operating margin with lower source-drain bias and enhanced output performance.
A Novel Accumulation Mode GAAC FinFET Transistor: Device Analysis, 3D TCAD Simulation and Fabrication
Authors: Xiao Deyuan , Chi Minhwa , Yuan David , Wang Xi , Yu Y , Wu Hanming , Xie Joseph
Published: March 2009

We report the analysis and TCAD results on gate-all-around cylindrical (GAAC) FinFET with operation based on channel accumulation. GAAC FinFETs operate in accumulation mode in which the current in accumulation is flowing across the whole cylinder-shaped Si body, have high mobility, reduced low-frequency noise and short-channel effects, increased the threshold voltage and avoid effects due to depletion of poly-Si gates. The Ion/Ioff ratio of the device can be larger than 10^6, a key parameter for device operation.
High Yield Patterning with Simplified DFM Rules in Sub-100nm Process Technologies
Authors: Chang Lifu , Choi Chang Il , Chi Minhwa
Published: March 2009

Traditional DFM methods of sub-100nm technologies have emphasized on the offering of optical proximity effect driven DFM rules for designers to reduce shape variations of the conducting patterns. This offering has been complicating over the rolling-out of new technologies in the past. The complication is most severe with the semiconductor foundries, which manufacture many different designs with the same set of tools. However, not only are the DFM rules an increasing work load, but recent reports also found new manufacturing failures are produced due to the shape changes on the design required by the DFM rules. A new DFM methodology that eliminates such problems is therefore necessary. In this paper, we show how we have achieved DFM in patterning with a significantly simplified set of DFM rules in our sub-100nm technology nodes. We have used photoresist with low activation energy and sensitive PEB properties to achieve high K1 values, and thus eliminating the need of most optical proximity effect driven rules. We also adopt an OPC flow that detects over-varying shapes and automatically performs incremental fix. These technologies simplify the DFM rules and minimize the number of the new problems coming from the traditional DFM method adopted by most foundries. We have achieved better than 90% for various logic and SoC products steadily.
Functionality, Yield and Reliability Analysis of SiGe Micro-mirrors using Automated Optical Measurement Techniques
Authors: De Wolf Ingrid , De Coster Jeroen , Varela Pedreira Olalla , Haspeslagh Luc , Witvrouw Ann
Published: March 2009

This paper discusses optical systems for automatic, wafer or chip level measurements of metrology, functional yield and reliability of MEMS. The functionality of the systems is demonstrated on megapixel arrays of SiGe micro-mirrors. The back-bone of the systems is formed by existing commercial systems, but home-developed procedures and software were written to extend their functionality and applicability.
Performance Improvement of CuOx RRAM for Non-volatile Applications
Authors: Lin Yinyin , Zhou Peng , Chi M.H , Lv H B. , Song S. , Huang R. , Wu J. G. , Wu H M.
Published: March 2009

We found CuOx thin film with gradual oxygen concentration (GOC) distribution enhances resistive switching characteristics for nonvolatile memory applications. Using Al/ GOC CuOx /Cu structure, not only no forming is needed, also the endurance of switching is greatly enhanced. The device with GOC CuOx demonstrates resistance on/off ratio greater than 100, and endurance of more than 12000 cycles. A ramped pulses series (RPS) operation method is also put forward, which can improve switching stability and cycling endurance remarkably. A method for minimizing the dispersion of Vreset by optimizing amplitude of pulse is proposed further. Dispersion of Vreset can be minimized by using optimized Vstart of RPS. And this phenomenon agrees well with the Joule heating model that the RESET process of memory switching is associated with rupturing of filaments by Joule heating.
Challenges and Opportunities for Optical CD Metrology in Future Lithography Process
Authors: Bao Junwei , Ferns Jason , Wen Youxian
Published: March 2009

As the IC industry is progressing towards 32 nm technology, Optical CD metrology will play an important role to help address many challenges in process control. OCD has the unique capability to characterize many critical dimensions in-line for complicated device structures nondestructively. Future process integration requires frequent W2W monitoring and feed forward / feedback control for critical layers. This makes integrated metrology (IM) a key option in process tools, and currently OCD is the only viable option for CD IM. In order to seize these opportunities, many improvements for OCD are need. Optical tools may need to be further optimized for better CD metrology performance. OCD modeling software should be able to model complicated structures and greatly boost ease of use. Furthermore, a well developed IM-SA OCD common platform is needed as the foundation for advanced process and equipment control.
Computation Lithography: Virtual Reality and Virtual Virtuality
Authors: Wong Alfred , Lam Edmund
Published: March 2009

Computation lithography is enabled by a combination of physical understanding, mathematical abstraction, and implementation simplification. An application in the virtual world of computation lithography can be a virtual reality or a virtual virtuality depending on its engineering sensible-ness and technical feasibility.
The Design Features of Ultimate Diamond Disks (UDD): W CMP with In-Situ Dressing of Metal Free Diamond Disks
Authors: Sung James C. , Hu Shao-Chung , Huang Wei , Chou Cheng-Shiang , Chou Chih-Chung , Pai Yang-Liang
Published: March 2009

All pad conditioners used for CMP today are made by attaching discrete diamond grits on a flat substrate. Polycrystalline diamond (PCD) was wire-EDM cut to form blades with different designs of cutting tips. These blades were assembled to form the so-called ultimate diamond disk (UDD). The pad asperities formed with UDD were compared with conventional diamond disks. It was confirmed that UDD dressed pad asperities were more uniform than that for polishing IC wafers today. The UDD dressed pads were also used to polish tungsten (W) IC layer deposited on 300 mm wafers. As the surface of PCD contains only merged diamond grains that are corrosion immune, UDD was dressing in-situ, by immersing in the acid slurry. The wafer uniformity so polished was comparable to that of ex-situ CMP pad dressing with metallized diamond disks. The in-situ dressing can boost the CMP throughput by deglazing the pad in real time while the wafer is being polished. After 15 hours, the wafer profiles for this in-situ dressing were sustained without decay.
Yield Enhancement with Optimized Offset Spacer Etch for 65nm Logic Low-leakage Process
Authors: Han Baodong , Chang Shih-Mou , Zhang Haiyang , Zhao Lin-Lin , Fu Ya-Li , Sun Wu , Liu Bing-Wu
Published: March 2009

This paper presents an effective way to reduce the degradation of the Ring-OSC speed with optimized offset spacer etch, improvement of the within-wafer uniformity of the offset spacer width and the reduction of its profile deviation. We have developed the lower offset spacer etch rate scheme for better control of plasma uniformity in order to achieve the above two targets. Compared with the 3Sigma of 1.3nm offset spacer width uniformity and 1.8nm profile deviation of conventional dielectric etcher with high etch rate, this low etch rate process has delivered the 3sigma of 0.5nm for the offset spacer width uniformity and 0.7nm offset spacer profile deviation. The corresponding Ring-OSC loss has been completely eliminated and the wafer-level yield is enhanced by 40%.
Microdot Epoxy Stamping Process Qualification for Substrate-Based Optocoupler BGA Packaging
Authors: Livelo Emmanuel I. , Rojas R'veen Pierangelo V.
Published: March 2009

Optocoupler is a semiconductor device that allows signal to be transferred between circuits, while keeping the circuits electrically isolated from each other. The demand of surface mount Optocoupler packaging has progressed from a conventional Dual-in-line packaging (DIP) to Small outline packaging (SOP) to miniflat packaging (MFP) and to Ball Grid Array Packaging (BGA) for Optocoupler. This innovative design employs the use of premolded lead frame technology offering thinner and smaller package structure. The need to maintain a consistent interconnect dispense material at die attach is very critical to attain a reliable adhesion of the epoxy to the die and to the substrate. Stamping or pin transfer approach was qualified as a die attach dispense system. This paper outlines the overall characterization work in the die attach process to meet the packaging requirement of the substrate based Optocoupler in a BGA package.
Influence of Sulfurization Temperature on Structure and Semiconducting Properties of SnxSy Thin Films
Authors: Cheng Shuying , Peng Shaopeng , Yang Yongli
Published: March 2009

SnxSy thin films were prepared by a two-step process. This process includes deposition of Sn films on glass substrates by thermal evaporation and sulfurization of Sn thin films in a vacuum condition at different temperatures of 150~300° for 45min. The microstructures, composition and photoelectrical properties of the films were investigated. The results show that, there are some differences in structure, phase and morphology for the films synthesized at different sulfurization temperatures. All the films are of p-type conduction. With the increase of the sulfurization temperature, Hall mobility and carrier concentration of the films are increased, whereas the resistivity is reduced. The films sulfurized at 240° are the best, and they are polycrystalline SnS films with orthorhombic structure. The SnS films have a strong {111} preferred orientation and good adhesion to the substrates. They are uniform with grain size of about 200~800 nm. The resistivity of the SnS film is 25.54Ω•cm.
Polysilicon Production: Reaction Engineering and Scaleup Issues
Authors: Ramachandran Palghat A.
Published: March 2009

In order to meet the increasing demand for solar energy utilization, polysilicon plants based on existing technologies are being built at an unprecedented rate and newer processes with better economic and environmental potentials are being evaluated. Reaction engineering, optimum reactor design and model based scaleup will therefore play a major role in achieving the dual objectives of capacity expansion and the reduction in cost of production. This paper reviews the various processes for manufacture of polysilicon and discusses the current state of the art in the reactor design and scaleup issues associated with polysilicon production, mainly for the emerging technology of fluid bed reactors.
Heat and Impurity Transfer Mechanisms of Czochralski and Directional Solidification Processes
Authors: Kakimoto Koichi , Chen Xuejiang , Liu L. J. , Miyazawa H. , Matsuo Hitoshi , Nakano Satoshi , Hisamatsu Sho , Kangawa Yoshihiro
Published: March 2009

In this paper, results of global computation in a three-dimensional configuration for transverse magnetic field-applied Czochralski method to study distributions of temperature and impurity concentration are presented. The analysis includes a re-melting and segregation model at an interface between a crystal and the melt. Deflection of an interface between a crystal and the melt is also taken into account. Time-dependent global analysis of the solidification process of a silicon ingot for photovoltaic is described in this paper. This model includes distributions of dislocation, impurity and point defects for a quasi-single silicon ingot grown by the solidification method. Heat and mass transfers in a square crucible are also discussed.
Calibration of the Enthalpy-Porosity Based Method for CZ Silicon Growth
Authors: Dai Bing , Devulapalli Balaji , Gunjalb Prashant , Kulkarni Milind
Published: March 2009

A global transport model for industrial Czochralski (CZ) silicon growth is reported in the paper. The model quantifies the temperature fields in all components of the growth system. The heat transport by the conduction, convection (melt and argon flows) and radiation are treated along with the momentum balance in the presence of the static magnetic fields. The crystallization process is modeled by an enthalpy-porosity method in which, the phase change occurs across a finite region defined by volumetric sink/source of heat (enthalpy) and momentum. The momentum sink/source is formulated based on the Darcy's law for porous medium, which is simply a numerical treatment for the isothermal solidification. The flow field in the Czochralski melt predicted by the global enthalpy-porosity based model is compared with that predicted by a more accurate simplified local model. Our studies indicate that the intensity of the flow induced by the presence of the crystal/melt interface is underestimated by the enthalpy-porosity based formulation.
Interactions of Cu and Ni Impurities with Vacancy-related Point Defects in Czochralski-grown Si Crystals
Authors: Markevich Vladimir , Peaker Anthony R. , Medvedeva Irina F. , Gusakov Vasilii E. , Murin Leonid I. , Svensson Bengt G.
Published: March 2009

It has been inferred from DLTS measurements on electron-irradiated Si samples contaminated with copper and nickel that divacancies (V2) and vacancy-oxygen complexes (VO) are effective traps for mobile Cu and Ni interstitial atoms. Interactions of these impurities with VO and V2 result in the enhanced annealing out of the VO and V2 defects as well as in the formation of new electrically active centers. An enhanced annealing of the VO and V2 defects in Si:Cu crystals is accompanied by an appearance of electron traps with the energy levels at Ec - 0.60 eV and Ec - 0.17 eV. It is argued that these levels are related to acceptor levels of Cu-VO and Cu-V2 complexes. The stable configuration of the Cu-VO complex has been determined by means of quantum-chemical calculations. In Si:Ni crystals an energy level at Ec - 0.365 eV is related to a complex incorporating at least one Ni atom and a radiation-induced defect.
Effect of Oxygen Precipitates in Annealed Electron Irradiated Czochralski Silicon
Authors: Chen Guifeng , Ma Xiaowei , Bai Yunna , Cai Lili , Li Yangxian
Published: March 2009

The precipitation of oxygen has been investigated for 1.5 MeV electron irradiated silicon samples with the dose of 3.5×1017 e/cm2. It has found that electron irradiation accelerated the oxygen precipitation in CZ-Si under higher annealing temperature. In addition, the effect of rapid thermal process (RTP) on the oxygen precipitation and on the denuded zone (DZ) formation in electron irradiated silicon wafers have been investigated by using optical microscope methods. The DZ can be formed at the surface in electron irradiated silicon wafers subjected to RTP pre-annealing. Furthermore, the width of DZ decreases with the RTP temperature.
Bicarbonate-dependent and bicarbonate-independent mechanisms contribute to nondiffusive uptake of acetate in the ruminal epithelium of sheep
Authors: Aschenbach Jörg R. , Bilk Sabine , Tadesse Gebrehiwot , Stumpff Friederike , Gäbel Gotthold
Published: March 2009

The present study investigated the significance of apical transport proteins for ruminal acetate absorption and their interaction with different anions. In anion competition experiments in the washed reticulorumen, chloride disappearance rate (initial concentration, 28 mM) was inhibited by the presence of a short-chain fatty acid mixture (15 or 30 mM of each acetate, propionate, and butyrate). Disappearance rates of acetate and propionate, but not butyrate (initial concentration, 25 mM each) were diminished by 40 or 80 mM chloride. In isolated ovine ruminal epithelia mounted in Ussing chambers, an increase in chloride concentration from 4.5 to 90 mM led to a decrease of apical acetate uptake at a concentration of 0.5 mM. Mucosal nitrate inhibited acetate uptake most potently whereas sulfate had no effect. Decreasing mucosal pH from 7.4 to 6.1 approximately doubled uptake of acetate both at 0.5 and 10 mM, but this doubling was almost abolished when HCO3− was absent. The stimulated uptake at mucosal pH 6.1 consisted of a bicarbonate-dependent, nitrate-inhibitable part ( Km = 54 mM) and a bicarbonate-independent component ( Km = 12 mM) that was also sensitive to nitrate inhibition. Maximal uptake was three times larger for bicarbonate-dependent vs. bicarbonate-independent uptake. Mucosal addition of 200 μM DIDS, 400 μM p-chloromercuribenzene sulfonic acid, 800 μM p-hydroxymercuribenzoic acid, or 100 μM phloretin had no effects on acetate uptake although the latter two inhibited l-lactate uptake. Our data conclusively show a dominant involvement of proteins in apical acetate uptake. Previously described pH effects on acetate absorption originate mainly from modulation of acetate/bicarbonate exchange. Additionally, there is bicarbonate-independent uptake of acetate anions that is protein coupled but not via monocarboxylate cotransporter.
Induction of p53 contributes to apoptosis of HCT-116 human colon cancer cells induced by the dietary compound fisetin
Authors: Lim Do Y. , Park Jung Han Yoon
Published: March 2009

Fisetin, or 3,3′,4′,7-tetrahydroxyflavone, is present in fruits and vegetables and has been previously reported to inhibit the proliferation of a variety of cancer cells (Lu X, Jung J, Cho HJ, Lim do Y, Lee HS, Chun HS, Kwon DY, Park JH. J Nutr 135: 2884–2890, 2005). We have demonstrated in a previous work that 20–60 μmol/l fisetin inhibits cyclin-dependent kinase activities resulting in cell cycle arrest in HT-29 colon cancer cells. In the present study, we attempted to characterize the mechanisms by which fisetin induces apoptosis in HCT-116 cells. DNA condensations, cleavage of poly(ADP-ribose) polymerase (PARP), and cleavage of caspases 9, 7, and 3 were induced in HCT-116 cells treated with 5–20 μmol/l of fisetin. Fisetin induced a reduction in the protein levels of antiapoptotic Bcl-xL and Bcl-2 and an increase in the levels of proapoptotic Bak and Bim. Fisetin did not affect the Bax protein levels, but induced the mitochondrial translocation of this protein. Fisetin also enhanced the permeability of the mitochondrial membrane and induced the release of cytochrome c and Smac/Diablo. Additionally, fisetin caused an increase in the protein levels of cleaved caspase-8, Fas ligand, death receptor 5, and TNF-related apoptosis-inducing ligand, and the caspase-8 inhibitor Z-IETD-FMK suppressed fisetin-induced apoptosis and the activation of caspase-3. Furthermore, fisetin increases p53 protein levels, and the inhibition of p53 expression by small interference RNA resulted in a decrease in the fisetin-induced translocation of Bax to the mitochondria, release of mono- and oligonucleosome in the cytoplasm, and PARP cleavage. These results show that fisetin induces apoptosis in HCT-116 cells via the activation of the death receptor- and mitochondrial-dependent pathway and subsequent activation of the caspase cascade. The induction of p53 results in the translocation of Bax to the mitochondria, which contributes to fisetin-induced apoptosis in HCT-116 cells.
Reduced carbohydrate availability does not modulate training-induced heat shock protein adaptations but does upregulate oxidative enzyme activity in human skeletal muscle
Authors: Morton James P. , Croft Louise , Bartlett Jonathan D. , MacLaren Don P. M. , Reilly Thomas , Evans Louise , McArdle Anne , Drust Barry
Published: March 2009

The primary aim of the present study was to test the hypothesis that training with reduced carbohydrate availability from both endogenous and exogenous sources provides an enhanced stimulus for training-induced heat shock protein (HSP) adaptations of skeletal muscle. A secondary aim was to investigate the influence of reduced carbohydrate availability on oxidative adaptations and exercise performance. Three groups of recreationally active men performed 6 wk of high-intensity intermittent running occurring four times per week. Group 1 ( n = 8; Low + Glu) and 2 ( n = 7; Low + Pla) trained twice per day, 2 days/wk, and consumed a 6.4% glucose or placebo solution, respectively, immediately before every second training session and at regular intervals throughout exercise. Group 3 ( n = 8; Norm) trained once per day, 4 days/wk, and consumed no beverage throughout training. Training induced significant improvements in maximal oxygen uptake (V̇o2max) ( P = 0.001) and distance covered on Yo-Yo Intermittent Recovery Test 2 ( P = 0.001) in all groups, with no difference between conditions. Similarly, training resulted in significant increases in HSP70, HSP60, and αB-crystallin in the gastrocnemius ( P = 0.03, 0.02, and 0.01, respectively) and vastus lateralis ( P = 0.01, 0.02, and 0.003, respectively) muscles in all groups, with no difference between conditions. In contrast, training resulted in significant increases in succinate dehydrogenase (SDH) activity of the gastrocnemeius (Low + Glu, Low + Pla, and Norm: 27, 76, and 53% increases, respectively; P = 0.001) and vastus lateralis muscles (Low + Glu, Low + Pla, and Norm: 17, 70, and 19% increases, respectively; P = 0.001) where the magnitude of increase in SDH activity was significantly larger for both muscles ( P = 0.03 and 0.04 for gastrocnemius and vastus lateralis, respectively) for subjects training in the Low + Pla condition. Data provide the first evidence that in whole body exercise conditions, carbohydrate availability appears to have no modulating effect on training-induced increases of the HSP content of skeletal muscle. In contrast, training under conditions of reduced carbohydrate availability from both endogenous and exogenous sources provides an enhanced stimulus for inducing oxidative enzyme adaptations of skeletal muscle although this does not translate to improved performance during high-intensity exercise.
Regulation of fat metabolism during resistance exercise in sedentary lean and obese men
Authors: Ormsbee Michael J. , Choi Myung Dong , Medlin Justin K. , Geyer Gabriel H. , Trantham Lauren H. , Dubis Gabriel S. , Hickner Robert C.
Published: March 2009

The effect of acute resistance exercise (RE) on whole body energy expenditure (EE) and α2-adrenergic receptor (α2-AR) regulation of lipolysis in subcutaneous abdominal adipose tissue (SCAAT) was determined in sedentary lean (LN) and obese (OB) men. Lipolysis was monitored using microdialysis in 10 LN [body mass index (BMI) 20.9 ± 0.6] and 10 OB (BMI 36.2 ± 2.7) men before, during, and for 24 h after RE. EE was measured before and immediately after RE for 40 min. Changes in interstitial glycerol were measured in SCAAT with three microdialysis probes perfused with a control solution, phentolamine (α2-AR antagonist), or propranolol (β-AR antagonist). EE and fat oxidation (FOX) were significantly ( P < 0.001) elevated immediately post-RE compared with pre-RE in LN and OB subjects, with no differences between groups. RE-induced increases in SCAAT glycerol concentrations from rest to peak exercise were greater in LN than in OB men in the control (LN 142.1 ± 30.8 vs. OB 65.4 ± 14.2%, P = 0.03) and phentolamine probes (LN 187.2 ± 29.6 vs. OB 66.7 ± 11.0%, P = 0.002). Perfusion of propranolol had no effect on interstitial glycerol concentrations over the time course of the experiment in either group. Plasma insulin concentrations were significantly lower ( P = 0.002) and plasma growth hormone (GH) was significantly higher ( P = 0.03) in LN compared with OB men. The mechanism behind RE contributing to improved body composition may in part be due to enhanced SCAAT lipolysis and improved EE and FOX in response to RE in LN and OB men. The blunted SCAAT lipolytic response to RE in OB compared with LN men is unrelated to RE-induced catecholamine activation of the antilipolytic α2-ARs and may be due to depressed GH in OB subjects.
Surfactant protein-D regulates the postnatal maturation of pulmonary surfactant lipid pool sizes
Authors: Ikegami Machiko , Grant Shawn , Korfhagen Thomas , Scheule Ronald K. , Whitsett Jeffrey A.
Published: March 2009

Surfactant protein (SP)-D plays an important role in host defense and pulmonary surfactant homeostasis. In SP-D-deficient ( Sftpd−/−) mice, the abnormal large surfactant forms seen at the ultrastructural level are taken up inefficiently by type II cells, resulting in an over threefold increase in the surfactant pool size. The mechanisms by which SP-D influences surfactant ultrastructure are unknown. We hypothesized that SP-D binds to surfactant immediately after being secreted and influences surfactant ultrastructure conversion. In newborn and adult sheep lungs, immunogold-labeled SP-D was associated with both lamellated membranous lipid structures of newly secreted surfactant and with small aggregate surfactant but not with tubular myelin. Since SP-D preferentially binds to phosphatidylinositol (PI) in vitro, the postnatal changes in PI were assessed. PI content in the bronchoalveolar lavage fluid increased after birth and peaked at 2–5 days of age, a time of rapid conversion of surfactant forms that is associated with the peak of surfactant lipid pool size. SP-D selectively interacted with PI-rich liposomes in vitro, causing their lysis. Similarly, the abnormal surfactant ultrastructure in Sftpd−/−mice was corrected by the addition of SP-D or melittin, and both peptides caused lysis of lipid vesicles. The normal conversion of surfactant ultrastructure requires SP-D that preferentially interacts with PI-rich, newly secreted surfactant, causing lysis of surfactant lipid membranes, converting the lipid forms into smaller surfactant lamellated structures that are critical for surfactant uptake by type II cells and normal surfactant homeostasis. SP-D regulates the dramatic decreases in the surfactant pool size that occurs in the newborn period.
Changes in the Electroencephalographic Spectrum in Response to Smoking Cues in Smokers and Ex-Smokers
Authors: Littel Marianne , Franken Ingmar H.A. , Van Strien Jan W.
Published: March 2009

Aims: To investigate the changes in the electroencephalographic (EEG) spectrum in smokers during exposure to a neutral and a smoking-related cue to determine whether these EEG changes are still present in ex-smokers after prolonged abstinence and to examine the relationship between the power in each spectral bandwidth and subjective craving. Methods: EEG frequencies in response to a smoking-related and a neutral cue were examined in 23 smokers and 21 ex-smokers, who quit smoking for 1.4 years on average. Additionally, self-report measures of cigarette craving and nicotine dependence were obtained. The spectral power of each bandwidth was computed, log-transformed, and analyzed using a within-subject design. Differences between EEG activity under neutral and smoking conditions were correlated with differences between pre- and postexperimental subjective craving. Results: Increases in reward craving (desire and intention to smoke) were associated with reduced theta activity, whereas increases in withdrawal craving (reduction of negative affect and withdrawal symptoms) were correlated with increases in both delta and higher alpha power. Furthermore, in smokers, but not in ex-smokers, a significant beta power increase was observed between the neutral condition and the smoking condition. Conclusion: Since the beta band is associated with arousal, attention, and alertness, it is suggested that the beta increase in response to the smoking cue might reflect an enhanced allocation of resources to smoking-related stimuli, i.e. a processing bias, which is an important feature of substance abuse. Since ex-smokers do not respond to the smoking cue with beta activity enhancement, we preliminarily conclude that smoking cues do not arouse ex-smokers or capture their attention as much as they do in smokers.
Multimodal Perioperative Rehabilitation in Elective Conventional Resection of Colonic Cancer: Results from the German Multicenter Quality Assurance Program ‘Fast-Track Colon II’
Authors: Braumann Chris , Guenther Nina , Wendling Peter , Engemann Rainer , Germer Christoph T. , Probst Wolfgang , Mayer Hans-P. , Rehnisch Bernd , Schmid Michael , Nagel Klaus , Schwenk Wolfgang
Published: March 2009

Aim: Multimodal perioperative rehabilitation in patients undergoing curative conventional colonic resection for cancer has not yet been studied in a multicenter setting. In 2005, a nationwide quality assurance program was initiated in Germany in an unselected patient population. Methods: The prospective multicenter data collection includes patients from 24 German hospitals. All hospitals had established ‘fast-track’ rehabilitation as the standard perioperative treatment in elective colonic resection, and all patients entered the registry. Results: 748 of 2,047 fast-track patients (36.5%) underwent open resection of colonic cancer. The median age of the 380 female and 368 male patients was 71 (26–96) years. Compliance was high for epidural analgesia (89%), systemic basic nonopioid analgesia (93%), ‘restrictive’ intraoperative intravenous fluids (81%), oral feeding (73%) and enforced mobilization (84%) on the day of surgery. Surgical complications were diagnosed in 20%, general morbidity occurred in only 13% of all patients, and 3 patients (0.4%) died in the early postoperative period. Readmission within 30 days of discharge was necessary in 27 patients (4%). Conclusions: Compliance with fast-track measures was high, and general morbidity was low in a population of patients undergoing multimodal perioperative rehabilitation for conventional colonic cancer resection.
Inpatient versus Day Clinic Treatment for Bulimia Nervosa: A Randomized Trial
Authors: Zeeck Almut , Weber Stefanie , Sandholz Angelika , Wetzler-Burmeister Edda , Wirsching Michael , Hartmann Armin
Published: March 2009

Background: In bulimia nervosa, more intense treatments are recommended if outpatient treatment fails. This is the first randomized controlled trial comparing the options of inpatient versus day clinic treatment. Method: Patients with severe bulimia nervosa were randomly assigned to inpatient or day clinic treatment of similar length and intensity. Specific and general psychopathology was assessed at the end of treatment and a 3-month follow-up. Results: Fifty-five patients were randomized; 22 day clinic patients and 21 inpatients started the program. At the end of treatment, a significant reduction of general and specific pathology was found in both settings. Following discharge, there was more deterioration in bulimic symptoms after inpatient treatment, but overall, results were comparable. Conclusions: Inpatient and day clinic programs are effective treatments for severely disturbed bulimic patients with similar results at the 3-month follow-up. Further follow-up will show if a higher instability of results after inpatient treatment is of importance in the long term.
Mesna for the Treatment of Hyperhomocysteinemia in Hemodialysis Patients
Authors: Cutler Murray J. , Urquhart Bradley L. , Freeman David J. , Spence J. David , House Andrew A.
Published: March 2009

Background: Increased plasma total homocysteine (tHcy) is a risk factor for the development of atherosclerosis and thrombosis present in over 90% of patients with end-stage renal disease (ESRD). We hypothesized that 12 mg/kg intravenous mesna administered predialysis would cause a significant decrease in plasma tHcy compared to placebo. Methods: Patients with ESRD were recruited for 1- and 4-week placebo-controlled, cross-over studies. Intravenous 12 mg/kg mesna or placebo was administered 3 times weekly predialysis. Results: One week of 12 mg/kg intravenous mesna significantly decreased predialysis plasma tHcy by 12.8 ± 7.8% (placebo 23.4 ± 8.0 μmol/l vs. mesna 20.5 ± 7.6 μmol/l, p = 0.0044). Four weeks of treatment yielded no significant decline in predialysis plasma tHcy (placebo 18.3 ± 8.5 μmol/l vs. mesna 18.7 ± 6.3 μmol/l, p = 0.41). Conclusions: Although 12 mg/kg mesna significantly enhances tHcy excretion, prolonged treatment causes no change in plasma tHcy.
Modulation of Paracetamol and Nefopam Antinociception by Serotonin 5-HT3 Receptor Antagonists in Mice
Authors: Girard Philippe , Pansart Yannick , Coppé Marie-Claude , Niedergang Betty , Gillardin Jean-Marie
Published: March 2009

Background/Aims: Post-operative nausea and vomiting are common adverse events that require administration of anti-emetic compounds, such as the serotonin 5-HT3 receptor antagonists, but these drugs can also reduce the analgesic efficacy of some analgesics (paracetamol, tramadol). Methods: The present study was designed to explore the effect of 3 serotonin 5-HT3 receptor antagonists on the antinociceptive efficacy of another frequently used post-operative analgesic, nefopam, in the mouse writhing and formalin tests. Results: Pre-treatment with tropisetron, ondansetron or MDL72222 did not significantly modify nefopam antinociception in both tests. However, paracetamol antinociception was blocked by ondansetron in the formalin test. Conclusion: These results provide a rationale for the clinical use of nefopam with anti-emetics during surgery.
Recurrent Septo-Optic Dysplasia Accompanied by Omphalocele: A Case Report
Authors: Tanrikulu Filiz , Korucuoglu Umit , Efeturk Tunay , Yildirim Fatma Doga , Biri Aydan
Published: March 2009

Septo-optic dysplasia, also known as de Morsier syndrome, is a rare congenital entity almost always characterized by hypoplasia/dysplasia of the optical nerve, chiasma or optic radiations and the complete or partial absence of the septum pellucidum. It may also be accompanied by other malformations, including multiple facial dysmorphism, midline defects, cleft lip and palate, musculoskeletal and other non-neurological eye features. Various cases have been reported which have presented various combinations of symptoms and stigmata of the syndrome. We here present a unique case of septo-optic dysplasia with familial repetition, a considerably early antenatal diagnosis and an accompanying omphalocele, a feature never before connected with the syndrome.