bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix‐assisted laser desorption/ionization time‐of‐flight analysis of low‐concentration oligonucleotides and mini‐sequencing products
Authors: Liu Yiding , Sun Xiyuan , Guo Baochuan
Published: October 2003

A new sample preparation procedure has been developed to improve the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) analysis of low‐concentration oligonucleotides. In this method, a few μL of the oligonucleotide solutions are first dispensed and allow drying and shrinking to a small spot on an anchoring target. Thereafter, a small volume (0.1 μL) of the saturated 3‐hydroxypicolinic acid (3‐HPA) solution is added to the top of the shrunk oligonucleotide spot. It is found that the sample prepared by this procedure is more homogenous and substantially reduces the need to search for ‘sweet’ spots. Importantly, the increased shot‐to‐shot and sample‐to‐sample reproducibility makes it possible to perform high‐throughput and quantitative analysis. We demonstrated that this procedure allowed the robust detection of oligonucleotides at a level of 0.01 μM and mini‐sequencing products produced using only 50 fmol of the extension primer. Copyright © 2003 John Wiley & Sons, Ltd.
Gas‐phase ligation of Cr+ and Fe+ with 4,9‐diazapyrene
Authors: Kazazić Saša , Klasinc Leo , Kovač Branka , Srzić Dunja
Published: October 2003

The ligation of Cr+ and Fe+ with 4,9‐diazapyrene (DAP) within a Fourier transform mass spectrometer was studied and compared with previous results for the ligands pyrene (Py) and 9‐azaphenanthrene (Ap). The results confirm that Fe+, which reacts more slowly but in the same way as Cr+ to bind two Py ligands, behaves quite differently with the nitrogen heterocycles DAP and Ap: it reacts rapidly and it binds three and four of them, respectively. Copyright © 2003 John Wiley & Sons, Ltd.
Surface oxidation kinetics of SiC powders in wet and dry air studied by x‐ray photoelectron spectroscopy and bremsstrahlung‐excited Auger electron spectroscopy
Authors: Wittberg Thomas N. , Wang Pu Sen , Hsu Stephen M.
Published: October 2003

Silicon carbide powder samples were heated at temperatures between 600 °C and 850 °C in wet and dry air to investigate the effect of moisture on the oxidation kinetics. Equations were derived to calculate the surface oxide thickness from both the Si 2p XPS spectra and from the Si KLL bremsstrahlung‐excited Auger spectra. The oxide film growth rates are shown to be parabolic. The film thickness formed during oxidation in wet air was larger than that in dry air for the same temperature and heating time. The activation energy for wet oxidation was found to be significantly lower than that for dry oxidation within this temperature range. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of surface orientation on the segregation kinetics of Sb from a Cu single crystal
Authors: Terblans J. J. , van Wyk G. N.
Published: October 2003

In a previous theoretical study it has been suggested that the bulk vacancy formation energy near a surface depends on the orientation of the surface. It has been suggested also that this dependency of the vacancy formation energy would influence the bulk diffusion coefficient near the surface. The experimental results presented in this paper support this hypothesis. The experimental results were obtained by measuring the bulk‐to‐surface segregation of Sb for a Cu(111) single crystal with 0.088 at.% Sb and for a Cu(110) single crystal with 0.082 at.% Sb. The experimental results were fitted with the vacancy‐modified Darken model and it was clear that the bulk diffusion coefficient beneath the (110) surface is higher than the bulk diffusion coefficient beneath the (111) surface. Copyright © 2003 John Wiley & Sons, Ltd.
Crystallinity of adsorbed EVA nanofilms: relevance to confinement and interfacial interactions
Authors: Elzein Tamara , Brogly Maurice , Schultz Jacques
Published: October 2003

We used infrared spectroscopy to estimate the crystalline component concentration in thin films of ethylene‐co‐vinyl acetate (EVA) copolymers spin‐coated on gold and functionalized substrates. Bulk calibration methods are elaborated that allow the establishment of quantitative relationships between infrared response and the degree of crystallinity via simple equations. These equations are applied and transposed to the study of thin films in such a way as to avoid preferential orientation effects induced by adsorption. Therefore, for calibration we select groups that vibrate in the same direction and belong to the crystalline phase. Our results show a decrease of the crystalline amount in EVA9, 14, 24 and 28 thin films, as determined on the basis of infrared spectroscopy experiments. The low crystallinity degree calculated for EVA thin films is in good agreement with the reduced crystalline morphology observed by atomic force microscopy.

Observed amorphization is considered to be induced by confinement (gold substrates) and interfacial interactions (functionalized substrates), which lead to a disordered chain conformation that makes crystallization less favourable. Copyright © 2003 John Wiley & Sons, Ltd.
Formation of a tetragonal Cu3Au alloy at gold/copper interfaces
Authors: Sarkar Subhendu , Datta Alokmay , Chakraborty Purushottam , Satpati Biswarup
Published: October 2003

A gold–copper alloy with a nominal composition of Cu3Au but with a tetragonal (c = 4a) structure is observed to form at Au/Cu interfaces of gold/copper multilayers deposited on amorphous substrates by d.c. magnetron sputtering. The formation of this non‐equilibrium structure (tentatively D023) under‐ambient conditions is detected by secondary ion mass spectrometry, x‐ray diffraction and high‐resolution cross‐sectional transmission electron microscopy. Co‐sputtering of Au and Cu under similar conditions produces only conventional fcc Cu3Au alloy phases, suggesting that interfacial confinement plays a significant role in producing the novel Cu3Au alloy phase in gold/copper multilayers. Copyright © 2003 John Wiley & Sons, Ltd.
In situ infrared spectroscopic studies of ultrathin inorganic film growth on zinc in non‐polymerizing cold plasmas
Authors: Shirtcliffe Neil James , Stratmann Martin , Grundmeier Guido
Published: October 2003

The effect of cold plasmas of oxygen, hydrogen, water and carbon dioxide on zinc samples was investigated. Oxygen plasma is known for its cleaning effect, hydrocarbons and water are removed from metal surfaces and the oxide layer is thickened. It was found that other oxygen‐containing gases had a similar effect. In addition, surface layers of other compounds were produced. The samples were investigated using XPS, Kelvin probe measurements and in situ infrared reflection absorption spectroscopy. Copyright © 2003 John Wiley & Sons, Ltd.
Anisotropy analysis of the surface energy of diamond cubic crystals
Authors: Zhang Jian‐Min , Ma Fei , Xu Ke‐Wei , Xin Xiao‐Tian
Published: October 2003

The surface energies for 24 surfaces of diamond structure cubic crystals of C, Si and Ge have been calculated using the modified embedded‐atom method. The results show that the three lowest surface energies correspond to the (111), (211) and (433) surfaces. Considering surface energy minimization solely, the (111), (211) and (433) textures should be favourable successively in diamond cubic films. The appearance of abnormal grains or textures with (111) and (211) orientations in Si, Ge and C films results from surface energy minimization. Copyright © 2003 John Wiley & Sons, Ltd.
Studies about the dispersion process and structure of impregnated CuO/ZrO2 systems
Authors: Yang Peng‐Cheng , Cai Xiao‐Hai , Zhao Li‐Yan , Xie You‐Chang , Xie Yaning , Hu Tiandou , Zhang Jing
Published: October 2003

The dispersion process and structure of impregnated CuO/ZrO2 systems were studied by x‐ray diffraction (XRD) and extended x‐ray absorption fine structure (EXAFS). The results showed that, after being calcined at 773 K, monolayer dispersed cupric nitrate decomposed into monolayer dispersed cupric oxide on zirconia's surface. The dispersion threshold of CuO was related to its precursor, cupric nitrate. The surface‐dispersed Cu nearest coordination structure changed into about five equally long Cu–O bonds. Copyright © 2003 John Wiley & Sons, Ltd.
Study of interface diffusion and reaction between Zr3N4 and stainless steel
Authors: Wang Li , Yin Musheng , Zhu Yongfa
Published: October 2003

The effect of annealing treatment on the interface diffusion and reaction between Zr3N4/stainless steel was studied by AES depth profiling along with line shape analysis. The Zr3N4 film was deposited on stainless‐steel substrates by reactive magnetron sputtering. Scanning electron microscopy, electron diffraction, AES and UV–VIS reflection were performed to characterize the deposited film. The results indicated that the interface diffusion between Zr3N4 and stainless steel took place during deposition and can be promoted by annealing treatment, but no interface reaction took place before or after annealing treatment. High‐temperature and long‐time annealing treatment resulted in obvious oxidation of the Zr3N4 layer. The UV–VIS reflection results indicated that the absorption band of Zr3N4 film shifted to shorter wavelength after annealing treatment. Copyright © 2003 John Wiley & Sons, Ltd.
Monte‐Carlo simulation of x‐ray photoelectron emission from silver
Authors: Zhang Zengming , Koshikawa Takanori , Iyasu Takeshi , Shimizu Ryuichi , Goto Keisuke , Tanaka Akihiro
Published: October 2003

Silver 3d x‐ray photoelectron spectroscopy (XPS) spectra were simulated with the Monte‐Carlo method using an effective energy‐loss function that was derived from a reflected electron energy‐loss spectroscopy (REELS) analysis based on an extended Landau approach. After confirming that Monte‐Carlo simulation based on the use of the effective energy‐loss function can successfully describe the experimental REELS spectrum and Ag 3d XPS spectrum, we applied Monte‐Carlo simulation to predict the angular distribution of Ag 3d x‐ray photoelectrons for different x‐ray incidence angles and different photoelectron take‐off angles. The experimental photoelectron emission microscope that we are constructing was confirmed as being close to the optimum configuration, in which the x‐ray incident angle as measured from the surface normal direction is 74° and the photoelectron take‐off angle is set normal to the surface. The depth distribution functions of the Ag 3d X‐ray photoelectrons for different energy windows suggest that the photoelectron emission microscope will exhibit greater surface sensitivity for narrower photoelectron energy windows. Copyright © 2003 John Wiley & Sons, Ltd.
AES and LEED study of well‐ordered oxide film grown on Cu–9at.%Al(111)
Authors: Yoshitake M. , Bera S. , Yamauchi Y.
Published: October 2003

An alloy of Cu–9at.%Al(111) has been oxidized in a low‐energy electron diffraction (LEED)/AES and a scanning AES instrument at elevated temperatures. Dosing with 1300 L of oxygen at 995 K gives rise to well‐ordered oxide layer formation on the Cu–9at.%Al alloy. The structure of the ordered oxide confirmed by LEED is ($7/\sqrt{3} \times 7/\sqrt{3}$) R30°. The chemical state of the oxide was Al2O3. The morphology of the surface observed with SEM in the scanning AES instrument revealed flat oxide growth with triangular defects of the same orientation. The possible epitaxy between the alloy substrate and alumina layer has been discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Density–depth profiles of an As‐implanted Si wafer studied by repeated planar sputter etching and total reflection x‐ray fluorescence analysis
Authors: Klockenkämper R. , Krzyżanowska H. , von Bohlen A.
Published: October 2003

The implantation of a high dose of high‐energy ions into an Si wafer causes amorphization of the original monocrystalline structure within a near‐surface layer. The in‐depth distribution of both Si atoms of the wafer and As ions implanted at a dose of 1 × 1017 ions cm−2 and an energy of 100 keV is studied. A novel method combining a repeated planar and broad sputter etching with differential weighing, surface analysis by total reflection x‐ray fluorescence and Tolansky interferometry is used for this investigation. Different depth profiles are recorded on the nanometre scale for the concentration defined as the mole ratio of As and Si, for the mass density of the implanted layer and for the number density of As and Si. The results generally correspond with measurements of Rutherford backscattering spectrometry and only deviate when the assumptions made for the mass density do not fit well. An appropriate approach to this quantity involves the number density of implanted ions but, furthermore, considers a variation of the number density of Si atoms during implantation, especially for a high dose and high‐energy implantation. The variation can be taken into account by a factor γ, where γ > 1 indicates compression and γ < 1 indicates extension of the original crystalline structure. For the above mentioned implantation, γ is measured separately for each sublayer to obtain accurate depth profiles. Copyright © 2003 John Wiley & Sons, Ltd.
First‐principles study of metal/nitride polar interfaces: Ti/TiN
Authors: Liu L. M. , Wang S. Q. , Ye H. Q.
Published: October 2003

We have examined the optimal interface structure, ideal work of adhesion and bonding character of polar Ti(110)/TiN(111) interfaces by first‐principles density‐functional plane‐wave pseudopotential calculations. Both Ti‐ and N‐terminated interfaces, including six different interface structures, were calculated. The interface structure for each termination, continuing the TiN crystal structure across the interface, has the largest work of adhesion. Although both terminations yield substantial adhesion energies in the range 3–7 J m−2, the N‐terminated interface is ∼4 J m−2 stronger than the Ti‐terminated interface. Analysis of the interfacial electronic structure shows that the Ti‐terminated interface is a mixed strong, metallic and weak covalent character, whereas the N‐terminated interface is a polar covalent bond similar to the Ti/TiC interface. Further study of the separation of the optimal interface shows that the cleavages will never fracture at the interface due to the strong bonding, which is consistent with the experimental results. Copyright © 2003 John Wiley & Sons, Ltd.
Lead underpotential deposition on Au(110)
Authors: Hale Penny , Thurgate Stephen , Wilkie Peter
Published: October 2003

The electrochemical underpotential deposition (UPD) of lead on Au(110) was investigated by XPS using a custom‐built ultrahigh vacuum apparatus containing a chamber for electrochemical studies. A two‐step deposition process for lead UPD was confirmed. A large increase in the surface concentration of oxygen was found in solutions containing lead. The presence of lead was detected on the gold surface at all potentials within the range investigated (−500 mV to 1500 mV vs. Ag/AgCl). Degradation of chlorine by x‐rays was observed. The change in surface components with potential was investigated and linked to models of UPD and oxidation. The initial random deposition of lead from solution led to surface disordering. Copyright © 2003 John Wiley & Sons, Ltd.
XPS C 1s binding energies for fluorocarbon–hydrocarbon microblock copolymers
Authors: Lei Yu‐Guo , Ng Kai‐Mo , Weng Lu‐Tao , Chan Chi‐Ming , Li Lin
Published: October 2003

Fluorocarbon–hydrocarbon microblock copolymers –(CF2)n–(CH2)m– (n = 4, 6, 8; m = 6, 8, 10) were synthesized. Binding energies of the C 1s and F 1s peaks of these copolymers were measured using x‐ray photoelectron spectroscopy. The binding energy of the C 1s peaks of the carbon atoms of the hydrocarbon segments was set at 285.0 eV as the binding energy reference. Unexpectedly, the binding energy of the C 1s peak corresponding to the CF2 group of the microblock copolymers was determined to be ∼291.4 eV, which is ∼0.8 eV lower than that of the CF2 group of tetrafluoroethylene. Copyright © 2003 John Wiley & Sons, Ltd.
Characterization of Pea Starches in the Presence of Alkali and Borax
Authors: Han Jee‐Yup , Tyler Robert T.
Published: October 2003

Refined field pea (Pisum sativum L.) starches were prepared from air‐classified pea starch by washing or from whole pea by wet milling, and analyzed for their physicochemical and pasting characteristics in the presence of alkali and borax. Commercial corn and high amylose corn starches were included in the study for comparative purposes. The two pea starches exhibited similar physicochemical characteristics. Amylose content markedly influenced pasting and other characteristics of the corn starches. Pea starch and high amylose corn starch exhibited little viscosity development during pasting in deionized water. The presence of alkali or borax significantly altered the peak viscosities and cold paste stabilities of all four starches in a concentration dependent manner. Alkali and borax increased peak and cold paste viscosity and reduced syneresis in all cases.
Processing Factors Affecting the Yield and Physicochemical Properties of Starch from Cassava Chips and Flour
Authors: Olomo Victor , Ajibola Obafemi
Published: October 2003

Three processing factors, namely, raw materials type (RMT) (i.e. chips and flour) and raw material drying mode (RDM) (i.e. sun‐ and oven‐drying at 55 °C) were related to the yield and some physicochemical properties of starch in a 23 factorial experiment. The quality characteristics investigated were: moisture content, pH, crude fiber content, peak viscosity and pasting temperature. Starch yields from oven‐dried chips and flour were significantly higher (at 5%) than from sun‐dried materials. The optimal yield of 55.9 g (per 70 g of dried product or 79.9%) was obtained from oven‐dried starch extracted from oven‐dried flour. The peak viscosities (PV) of starches extracted from flour and chips were similar while the observed pasting temperatures of flour‐extracted starches were not significantly different from those derived from chips.
Physical Basis for Separation of Rice Starch using Various Density Gradient Systems and its Effect on Starch Recovery, Purity, and Pasting Properties
Authors: Guraya Harmeet S. , James Charles , Champagne Elaine T.
Published: October 2003

A 32% waxy and non waxy rice flour slurry containing starch‐protein agglomerates was physically disrupted in presence of water by use of high pressure homogenizer called Microfluidizer®. Microfluidized rice flour slurry from passes 2 and 4 was collected followed by isolation of starch using three different density gradient solutions/systems (CeCl, NaCl/sucrose and ZnSO4·7H2 O). Complete deagglomeration was obtained after passing the rice flour slurry four times through the Microfluidizer®. The recovery of isolated starch varied from 76.28% to 91.20% for different density gradient systems. The degree of deagglomeration did not seem to affect recovery but affected the purity of the isolated starches. All starches produced from pass 4 rice slurry resulted in starches with residual protein below 0.5%. Higher density of the gradient solution resulted in higher recovery and purity of starch. The isolation method had a significant effect on the pasting properties of the isolated starch. Residual protein in isolated starch had a negative correlation with peak viscosity and setback of pass 2 waxy and nonwaxy starches. The salts were retained in purified starch despite rigorous washing (at least 75 times greater than the control) and could affect starch properties.
Improved Calcium Sequestering Carbohydrate Based Agents
Authors: Besemer Arie C. , Jetten Jan M. , Slaghek Ted M.
Published: October 2003

The improved tandem oxidation sequence of starch with the aim of developing, e.g. degradable co‐builders suitable for laundry formulations as an alternative to the currently used polyacrylates is described. The tandem oxidation of starch starts with sodium periodate treatment of granular starch followed by oxidation of the dialdehyde product with sodium chlorite to dicarboxy starch. It turns out that improving the periodate oxidation resulting in a more complete transformation of the glucose moiety into the dialdehyde product yields, after sodium chlorite oxidation, a dicarboxy starch with a calcium sequestering capacity of 3.3 mmol Ca2+ per gram of dicarboxy product. This is an improvement of about 25% compared with current literature data.
Characterization and Utilization of Acid‐modified Rice Starches for Use in Pharmaceutical Tablet Compression
Authors: Puchongkavarin Hatairat , Bergthaller Wolfgang , Shobsngob Sujin , Varavinit Saiyavit
Published: October 2003

Acid modified, agglomerated starches offer specific advantages as fillers in production of pharmaceutical tablets. Spray drying can improve processing of tablet mixtures significantly. In order to investigate prerequisites in utilization of rice starch, non‐waxy and waxy types were partially hydrolyzed in 6% (w/v) HCl solution at room temperature for varied length of time to obtain rice starches with increased crystallinity (so‐called crystalline rice starches). Scanning electron micrographs of native and highly crystalline starches were used to study the morphological changes and to suggest the mode of acid attack during hydrolysis. Exo‐corrosion distributed over the surface of acid‐modified waxy rice starch (AWRS) was observed after 192 h of hydrolysis. In contrast, the surface of acid‐modified rice starch (ARS) remained unchanged at 192 h of acid hydrolysis. The amylose content and the median particle size (diameter) were reduced with increasing hydrolysis time. It was found by X‐ray diffraction that the relative crystallinity of acid‐modified starches at >95% relative humidity was clearly increased with prolonged hydrolysis time.

For studying tablet properties spherical agglomerates of the native and acid modified starches were directly compressed at 4 kN to obtain tablets. Crushing strength and disintegration time of tablets increased with relative crystallinity. In contrast, tablet friability was reduced. Concerning tablet functionality, the crystalline starches were positioned in overlapping ranges between the common commercial tablet fillers (microcrystalline cellulose, pregelatinized starch and lactose, respectively).
Evidence that the metabotropic glutamate receptor 5 antagonist MPEP may act as an inhibitor of the norepinephrine transporter in vitro and in vivo
Authors: Heidbreder Christian A. , Bianchi Massimiliano , Lacroix Laurent P. , Faedo Stefania , Perdona Elisabetta , Remelli Rosaria , Cavanni Paolo , Crespi Francesco
Published: October 2003

The mechanisms through which blockade of metabotropic glutamate receptors 5 (mGluR5) results in anxiolytic and antidepressant effects are currently unknown. In the present study, we therefore hypothesized that the anxiolytic‐ and antidepressant‐like profile of the noncompetitive mGluR5 receptor antagonist 2‐ethyl‐6‐(phenylethynyl)‐pyridine (MPEP) may be mediated by inhibition of the norepinephrine transporter (NET). Accordingly, we first examined the potency of MPEP to bind to or inhibit uptake at the NET as well as the dopamine and serotonin transporters (DAT and SERT, respectively). We also examined the simultaneous in vivo effects of MPEP and desipramine (DMI) on both NE‐like oxidation current in the amygdala (AMY) and cell firing in the locus coeruleus (LC) by means of differential pulse voltammetry (DPV) coupled with electrophysiology. MPEP completely displaced the binding of [3H]‐nisoxetine on human NET with a pKi of 6.63 ± 0.02. In addition, MPEP was able to inhibit [3H]‐NE uptake in LLCPK cells expressing human NET, with a pIC50 of 5.55 ± 0.09. In vivo DPV data revealed that both MPEP (30 mg/kg i.p.) and DMI (10 mg/kg i.p.) significantly increased NE‐like voltammetric responses levels in the AMY, whereas both compounds also significantly decreased cell firing monitored concomitantly from the second microelectrode in the LC. Collectively, the results of the present study provide potential new mechanisms through which MPEP exerts its anxiolytic and antidepressant effects. Synapse 50:269–276, 2003. © 2003 Wiley‐Liss, Inc.
Early embryonic death of glutamate carboxypeptidase II (NAALADase) homozygous mutants
Authors: Tsai G. , Dunham K.S. , Drager U. , Grier A. , Anderson C. , Collura J. , Coyle J.T.
Published: October 2003

Glutamate carboxypeptidase II (EC 3.4.17.21) catalyzes the hydrolysis (Km = 0.2 μM) of the neuropeptide N‐acetylaspartylglutamate to yield N‐acetylaspartate and glutamate and also serves as a high‐affinity folate hydrolase in the gut, cleaving the polyglutamate chain to permit the absorption of folate. N‐acetylaspartylglutamate is an agonist at the mGluR3 metabotropic receptor and a source of extracellular glutamate through hydrolysis by glutamate carboxypeptidase II. Given the important role of glutamate in brain development and function, we were interested in the effects of a null mutation of glutamate carboxypeptidase II that would potentiate the effects of N‐acetylaspartylglutamate. The PGK‐Neomycin cassette was inserted to delete exons 9 and 10, which we previously demonstrated encode for the zinc ligand domain essential for enzyme activity. Successful germline transmission was obtained from chimeras derived from embryonic stem cells with the targeted mutation of glutamate carboxypeptidase II. Homozygous null mutants did not survive beyond embryonic day 8. Folate supplementation of the heterozygous mothers did not rescue the homozygous embryos. Mice heterozygous for the null mutation appeared grossly normal and expressed both mutated and wild‐type mRNA but the activity of glutamate carboxypeptidase II is comparable to the wild‐type mice. The results indicate that the expression of glutamate carboxypeptidase II is upregulated when one allele is inactivated and that its activity is essential for early embryogenesis. Synapse 50:285–292, 2003. © 2003 Wiley‐Liss, Inc.
Stimulation of postsynaptic α1b‐ and α2‐adrenergic receptors amplifies dopamine‐mediated locomotor activity in both rats and mice
Authors: Villégier Anne‐Sophie , Drouin Candice , Bizot Jean‐Charles , Marien Marc , Glowinski Jacques , Colpaërt Francis , Tassin Jean‐Pol
Published: October 2003

Recent experiments have shown that mice lacking the α1b‐adrenergic receptor (α1b‐AR KO) are less responsive to the locomotor hyperactivity induced by psychostimulants, such as D‐amphetamine or cocaine, than their wild‐type littermates (WT). These findings suggested that psychostimulants induce locomotor hyperactivity not only because they increase dopamine (DA) transmission, but also because they release norepinephrine (NE). To test whether NE release could increase DA‐mediated locomotor hyperactivity, rats were treated with GBR 12783 (10 mg/kg), a specific inhibitor of the DA transporter, and NE release was enhanced with dexefaroxan (0.63–10 mg/kg), a potent and specific antagonist at α2‐adrenergic receptors. Dexefaroxan increased the GBR 12783‐mediated locomotor response by almost 8‐fold. The role of α1b‐ARs in this effect was then verified in α1b‐AR KO mice: whereas dexefaroxan (1 mg/kg) doubled locomotor hyperactivity induced by GBR 12783 (14 mg/kg) in WT mice, it decreased it by 43% in α1b‐AR KO mice. Finally, to test whether this latter inhibition was related to the occupation of α2‐adrenergic autoreceptors or of α2‐ARs not located on noradrenergic neurons, effects of dexefaroxan on locomotor hyperactivity induced by D‐amphetamine (0.75 mg/kg) were monitored in rats depleted in ascending noradrenergic neurons. In these animals dexefaroxan inhibited by 25–70% D‐amphetamine‐induced locomotor hyperactivity. These data indicate not only that the stimulation of α1b‐ARs increases DA‐mediated locomotor response, but also suggest a significant implication of postsynaptic α2‐ARs. Involvement of these adrenergic receptor mechanisms may be exploited in the therapy of Parkinson's disease. Synapse 50:277–284, 2003. © 2003 Wiley‐Liss, Inc.
Synaptic plasticity in rat subthalamic nucleus induced by high‐frequency stimulation
Authors: Shen Ke‐Zhong , Zhu Zi‐Tao , Munhall Adam , Johnson Steven W.
Published: October 2003

The technique of deep brain stimulation (DBS) has become a preferred surgical choice for the treatment of advanced Parkinson's disease. The subthalamic nucleus (STN) is presently the most promising target for such DBS. In this study, whole‐cell patch‐clamp recordings were made from 46 STN neurons in rat brain slices to examine the effect of high‐frequency stimulation (HFS) of the STN on glutamatergic synaptic transmission in STN neurons. HFS, consisting of trains of stimuli at a frequency of 100 Hz for 1 min, produced three types of synaptic plasticity in 17 STN neurons. First, HFS of the STN induced short‐term potentiation (STP) of evoked postsynaptic current (EPSC) amplitude in four neurons. STP was associated with a reduction in the EPSC paired‐pulse ratio, suggesting a presynaptic site of action. Second, HFS of the STN generated long‐term potentiation (LTP) of EPSC amplitude in eight neurons. Although the EPSC paired‐pulse ratio was reduced transiently in the first 2 min following HFS, ratios measured 6–20 min after HFS were unchanged from control. This suggests that LTP is maintained by a postsynaptic mechanism. Third, HFS produced long‐term depression (LTD) of EPSC amplitude in five STN neurons. LTD was associated with a significant increase in EPSC paired‐pulse ratios, indicating a presynaptic site of action. These results suggest that HFS can produce long‐term changes in the efficacy of synaptic transmission in the STN. HFS‐induced synaptic plasticity might be one mechanism underlying the effectiveness of DBS in the STN as a treatment of advanced Parkinson's disease. Synapse 50:314–319, 2003. © 2003 Wiley‐Liss, Inc.
Activation of metabotropic glutamate receptor 5 is associated with effect of amphetamine on brain neurons
Authors: Yu Meng‐Fen , Lin Wan‐Wan , Li Li‐Tzu , Yin Hsiang‐Shu
Published: October 2003

The role of metabotropic glutamate receptor 5 (mGluR5) was explored in mechanisms underlying the action of amphetamine (AMPH). The activity of mGluR5 was monitored by measuring the level of [3H]inositol monophosphates in brain neurons, in response to stimulation of 2‐choloro‐5‐hydroxyphenylglycine (CHPG), a selective agonist of mGluR5. Treatment with 1 μM of AMPH for 1 h or 7 days increased the CHPG (1 mM, 30 min)‐evoked phosphoinositide turnover by 46% or 92% and 26% or 84% in cultured cortical and hippocampal neurons, respectively, from that of CHPG‐only treated cells. When AMPH was present during CHPG application post‐1 h or 7 day AMPH incubation, the rate of phosphoinositide hydrolysis in cortical neurons became 121% or 142% higher than that treated with CHPG only. The postnatal day (P) 21 (juvenile) and P60 (adult) rats received three intraperitoneal injections of 5 mg/kg of AMPH or saline daily for 6 days. They were challenged on the eighth day with one dosage and sacrificed 3 h later. Reversible 3H‐glutamate binding detected increases of 22–89% in the binding levels of cortex and hippocampus of both ages following the AMPH injections. Increases of 13–18% in the levels of mGluR5 mRNA were seen in the juvenile pyramidal neurons of hippocampal CA1‐4, granular cells of dentate gyrus, and ventral thalamic nuclei, as shown by in situ hybridization. The AMPH‐induced altered activity of mGluR5 is probably associated with changes in the expression of the glutamate receptors, including mGluR5. AMPH may modify the sensitivity of mGluR5 or interact with the receptor itself. Synapse 50:334–344, 2003. © 2003 Wiley‐Liss, Inc.
Characterization of fluoxetine plus olanzapine treatment in rats: A behavior, endocrine, and immediate‐early gene expression analysis
Authors: Horowitz Judith M. , Goyal Alpna , Ramdeen Navindra , Hallas Brian H. , Horowitz A. Thomas , Torres German
Published: October 2003

A large number of individuals afflicted with psychiatric disorders, particularly depression with psychotic features, do not respond to conventional drug therapy. An option for this phenomenon is to augment a standard selective serotonin (5‐HT) reuptake inhibitor with an atypical antipsychotic agent. In this regard, fluoxetine and olanzapine have been used concomitantly for treatment‐resistant depression and bipolar depression. Although highly efficacious in terms of producing superior improvement of symptoms across a variety of psychological measures, the motor patterns, endocrine profiles, and intracellular signaling pathways affected by drug augmentation have not been determined. Here we show that fluoxetine (10 mg/kg) plus olanzapine (5 mg/kg) given to rats for 7 consecutive days (i.e., subchronic treatment) alters motor activity and diminishes spontaneous behaviors as measured by spatial position and angular path analyses. In addition, the same drug combination pattern sensitizes peak adrenal corticosterone secretion without altering serum glucose levels. We also show that subchronic fluoxetine and olanzapine exposure suppresses the induction of two immediate‐early gene transcription factors (e.g., pCREB and FOS) that are associated with long‐lasting changes in synaptic efficacy and structural modifications in the prefrontal cortex, piriform cortex, and hippocampus. These results suggest that fluoxetine plus olanzapine can interact in a fashion not predicted by the currently accepted model of fluoxetine monotherapy and provide insight into the synergistic actions of drug augmentation in patients with treatment‐resistant depression. Synapse 50:353–364, 2003. © 2003 Wiley‐Liss, Inc.
One‐step measurement of firefly luciferase activity in yeast
Authors: Leskinen P. , Virta M. , Karp M.
Published: October 2003

Firefly luciferase is often used as a sensitive genetic reporter in various cell types. The pitfall in yeast, however, has been the need to break down the rigid cells in order to measure the enzyme activity. In this study we have removed the peroxisomal targeting codons from the Photinus pyralis luciferase gene (luc) and shown that in the yeast Saccharomyces cerevisiae this modified luciferase gives high levels of light emission that is easy to measure from intact living cells. Furthermore, cells with the modified luciferase grew essentially faster than those with the wild‐type luciferase, indicating that peroxisomal targeting of a foreign enzyme puts some constraints to cellular viability. As a model system we used two different reporter constructs. In the first, expression of the luciferase gene is under control of CUP1‐promoter, a well known yeast promoter that is inducible by copper ions. In the second, luciferase activity is dependent on activation of the human oestrogen receptor and its interaction with oestrogen‐responsive elements incorporated in a yeast promoter. The luciferase activity measurement could be done on a 96‐well plate by simple addition of the substrate, D‐luciferin, at a moderately acidic pH of 5.0. The ease of use of the non‐peroxisomal luciferase makes it an interesting alternative for reporter genes that are conventionally used in yeast, such as lacZ. Copyright © 2003 John Wiley & Sons, Ltd.
MIG1‐dependent and MIG1‐independent regulation of GAL gene expression in Saccharomyces cerevisiae: role of Imp2p
Authors: Alberti Adriana , Lodi Tiziana , Ferrero Iliana , Donnini Claudia
Published: October 2003

Imp2p (Yil154c) is a transcriptional activator involved in glucose derepression of the maltose, galactose and raffinose utilization pathways and in resistance to thermal, oxidative or osmotic stress. We analysed the role of Imp2 in the regulation of GAL genes. Imp2 was shown to have a positive effect on glucose derepression of Leloir pathway genes and their activator gene GAL4. The effect of Imp2 on galactose metabolism was shown to be partially dependent on Mig1p. The Mig1‐independent role depends on Nrg1p. However, disruption of both MIG1 and NRG1 only partially relieves the glucose repression of GAL genes in the Δimp2 mutant, indicating that Imp2 must also have other function(s). Moreover, the interaction between IMP2 and GAL6/BLH1, a recently isolated gene involved in the regulation of GAL genes that shares with Imp2 the ability to protect cells from the glycopeptide bleomycin, was also analysed. The results suggest a major role of Imp2 in a GAL6‐independent pathway. Copyright © 2003 John Wiley & Sons, Ltd.
Role of the non‐respiratory pathways in the utilization of molecular oxygen by Saccharomyces cerevisiae
Authors: Rosenfeld Eric , Beauvoit Bertrand
Published: October 2003

Saccharomyces cerevisiae is a facultative anaerobe devoid of mitochondrial alternative oxidase. In this yeast, the structure and biogenesis of the respiratory chain, on the one hand, and the functional interactions of oxidative phosphorylation with the cellular energetic metabolism, on the other, are well documented. However, to our knowledge, the molecular aspects and the physiological roles of the non‐respiratory pathways that utilize molecular oxygen have not yet been reviewed. In this paper, we review the various non‐respiratory pathways in a global context of utilization of molecular oxygen in S. cerevisiae. The roles of these pathways are examined as a function of environmental conditions, using either physiological, biochemical or molecular data. Special attention is paid to the characterization of the so‐called ‘cyanide‐resistant respiration’ that is induced by respiratory deficiency, catabolic repression and oxygen limitation during growth. Finally, several aspects of oxygen sensing are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
The ICL1 gene of Pichia pastoris, transcriptional regulation and use of its promoter
Authors: Menendez Javier , Valdes Iris , Cabrera Nelson
Published: October 2003

We cloned and characterized a gene encoding isocitrate lyase from the methylotrophic yeast Pichia pastoris. This gene was isolated from a P. pastoris genomic library using a homologous PCR hybridization probe, amplified with two sets of degenerate primers designed from conserved regions in yeast isocitrate lyases. The cloned gene was sequenced and consists of an open reading frame of 1563 bp encoding a protein of 551 amino acids. The molecular mass of the protein is calculated to be 60.6 kDa with high sequence similarity to isocitrate lyase from other organisms. There is a 64% identity between amino acid sequences of P. pastoris Icl and Saccharomyces cerevisiae Icl. Northern blot analyses showed that, as in S. cerevisiae, the steady‐state ICL1 mRNA levels depend on the carbon source used for cell growth. Expression in P. pastoris of the dextranase gene (dexA) from Penicillium minioluteum under control of the ICL1 promoter proved that PICL1 is a good alternative for the expression of heterologous proteins in this methylotrophic yeast. The sequence presented here has been deposited in the EMBL data library under Accession No. AJ272040. Copyright © 2003 John Wiley & Sons, Ltd.
Ter Linde JJM, Régnacq M and Steensma HY. 2003. Transcriptional regulation of YML083c under aerobic and anaerobic conditions. Yeast20: 439–454.
Authors: Ter Line J. J. M. , Régnacq M , Steensma H. Y.
Published: October 2003

The original article to which this Erratum refers was published in Yeast 20: 439–454. Copyright © 2003 John Wiley & Sons, Ltd.
Expression in Escherichia coli of a recombinant adenosine kinase from Saccharomyces cerevisiae: purification, kinetics and substrate analyses
Authors: Barrado Patricia , Rodríguez María José , Jiménez Antonio , Lobato María Fernández
Published: October 2003

The Saccharomyces cerevisiae ADO1 gene is known to encode a homologue of eukaryotic adenosine kinases. This gene was expressed in Escherichia coli as a recombinant protein fused to a polyhistidine tag by using the rhamnose‐inducible bacterial promoter rhaB. The recombinant protein was purified to apparent homogeneity and its ability to phosphorylate different substrates was evaluated. Adenosine (Km 3 µM) is its primary substrate. In addition, it also phosphorylates, albeit less efficiently, 3′‐deoxyadenosine (cordycepin; Km 1.84 mM) and 3′‐amino‐3′‐deoxyadenosine (Km 0.26 mM). Other kinetic properties of the recombinant enzyme have also been determined. Copyright © 2003 John Wiley & Sons, Ltd.
Genetic diversity of green algal and cyanobacterial photobionts in Nephroma (Peltigerales)
Authors: Lohtander Katileena , Oksanen Ilona , Rikkinen Jouko
Published: October 2003

Genetic diversity of green algal and cyanobacterial photobionts in Nephroma was examined by using nucleotide sequences of the ribosomal gene cluster. The lichens studied included both bipartite and tripartite species. There was very little variation in green algal-ITS sequences of N. arcticum and N. expallidum. Almost identical sequences were obtained from all thalli analysed and also from two tripartite Peltigera species. On the basis of SSU rDNA data the green algal photobionts of N. arcticum are closely related to the primary photobiont of P. britannica, and also to an endophytic alga of Ginkgo biloba. The SSU rDNA region of lichen-forming cyanobacteria was rather variable. A phylogenetic analysis indicated that the Nostoc specimens formed a monophyletic group and the strains were divided into two main groups. One clade included only cyanobionts of lichens, including those of all bipartite Nephroma species. The second group was genetically more heterogeneous and included mainly cyanobionts of terricolous cyanolichens, including those of both tripartite Nephroma species studied. The distinction between bi- and tripartite Nephroma species is significant as the mycobionts of tripartite species are not monophyletic. It implies that within Nephroma, evolutionary transitions between symbiosis types cannot have been achieved simply via an acquisition or loss of the green algal photobiont. As the Nostoc symbionts of bi- and tripartite species belong to different phylogenetic groups, an evolutionary change in green algal association has required a concurrent change in cyanobiont composition.
Spatial distribution of otter trawl effort in Icelandic waters: comparison of measures of effort and implications for benthic community effects of trawling activities
Authors: Ragnarsson Stefán Áki , Steingrímsson Sigmar Arnar
Published: October 2003

We examined the spatial distribution of trawling effort from logbook data from all Icelandic vessels fishing for demersal fish between 1991 and 1997 with a spatial resolution of 1 degree of latitude and 1 degree of longitude. The trawling effort was widely distributed but was intensive only in small and localised areas. Three measures of effort were compared; tow frequency, tow duration and separate estimates of swept area for otter boards and trawls. In each year, the area swept with otter trawl was 1.7 times greater than the total area in which fishing occurred over the 7 year period. In contrast, the area swept with otter boards was 4% of the total fishing area. Most of the fishing effort was confined to depths shallower than 400 m. With increasing depth, the size of trawls became larger and accordingly, also the area swept per haul. Calculations assuming no variation in the size of the trawl in relation to depth, produced inaccurate swept area estimates. Furthermore, swept area estimates based on depth corrected door spreads were greater than estimates where no such correction was made. Swept area was considered to be a more appropriate measure of effort than tow frequency and tow duration as long as variation in the size of the gear (e.g. in relation to depth) was taken into account. Effort within Icelandic waters was compared in five depth strata within seven zones. Effort was highest off the south and NW coasts and lowest off the north and east coasts. Effort was most intensive at the 100–500 m depth in all zones but in some areas (such as off NW Iceland), effort extended to deeper waters. Knowledge of the distribution of fishing effort is important for predicting larger scale effects of fishing gears on benthic communities.
The role of incisors in selective grazing by cattle and horses
Authors: HONGO A. , AKIMOTO M.
Published: October 2003

To clarify the role of the incisors in selective grazing by cattle and horses, experiments were conducted in July 1999, using three Holstein cattle and three thoroughbred horses to investigate bite weight and bite force using hand-constructed swards with 15 loadcells spaced 6×12 cm apart. Leaves of perennial ryegrass (Lolium perenne: PRG) were mixed with leaves of tall fescue (Festuca arundinacea: TF) or reproductive culms of reed canarygrass (Phalaris arundinacea: RCG).

There was little difference between cattle and horses in bite rate, but DM intake rate of horses was almost twice that of cattle in the PRG/TF mixture. In the PRG/RCG mixture, both animals tended to graze only leaves of PRG. Total bite force was 3270–3280 N/min in cattle and 5350–6350 N/min in horses in the PRG/TF mixture. Means of maximum values of one bite force (not total force per bite) were 88±5·5 N in cattle and 141±11·0 N in horses. These values corresponded to 1·6±0·10% of body weight in cattle and 2·2±0·16% in horses, after converting Newton force into kilogram force. Bite area was higher in horses than in cattle. Both cattle and horses did not discriminate between leaves of PRG and TF. In the PRG/RCG mixture, horses prehended both leaves and culms in 33% of total clumps grazed, compared with only 5% in cattle. Many culms escaped from the mouth at the moment of prehension. In mixtures of soft leaves and stiff stems, the lack of upper incisors in cattle may have the advantage over horses. The term ‘comb-out strategy’ is proposed for this selective foraging by cattle. DM intake per bite force was highest in TF leaves (7·5 mg DM/N) grazed by horses and similar (3·7–4·6 mg DM/N) in PRG leaves grazed by both cattle and horses.
A comparative evaluation of functions for the analysis of growth in male broilers
Authors: DARMANI KUHI H. , KEBREAB E. , LOPEZ S. , FRANCE J.
Published: October 2003

Data from six studies with male broilers fed diets covering a wide range of energy and protein were used in the current two analyses. In the first analysis, five models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine metabolizable energy intake at maintenance and efficiency of utilization of metabolizable energy intake for producing gain. In addition to the straight line, two types of functional form were used. They were forms describing (i) diminishing returns behaviour (monomolecular and rectangular hyperbola) and (ii) sigmoidal behaviour with a fixed point of inflection (Gompertz and logistic). These models determined metabolizable energy requirement for maintenance to be in the range 437–573 kJ/kg of body weight/day depending on the model. The values determined for average net energy requirement for body weight gain varied from 7·9 to 11·2 kJ/g of body weight. These values show good agreement with previous studies. In the second analysis, three types of function were assessed as candidates for describing the relationship between body weight and cumulative metabolizable energy intake. The functions used were: (a) monomolecular (diminishing returns behaviour), (b) Gompertz (smooth sigmoidal behaviour with a fixed point of inflection) and (c) Lopez, France and Richards (diminishing returns and sigmoidal behaviour with a variable point of inflection). The results of this analysis demonstrated that equations capable of mimicking the law of diminishing returns describe accurately the relationship between body weight and cumulative metabolizable energy intake in broilers.