julilili42/papers huggingface dataset:
K+‐dependent gating of Kir1.1 channels is linked to pH gating through a conformational change in the pore
2001-07-01

1. We have used giant patch-clamp recording to investigate the interaction between pH gating and K(+)-dependent gating in rat K(ir)1.1 (ROMK) channels heterologously expressed in Xenopus oocytes. 2. Gating by intracellular protons (pH gating) and extracellular K(+) ions (K(+)-dependent gating) is a hallmark of K(ir)1.1 channels that mediate K(+) secretion and control NaCl reabsorption in the kidney. pH gating is driven by protonation of an intracellular lysine residue (K80 in K(ir)1.1). K(+)-dependent gating occurs upon withdrawal of K(+) ions from the extracellular side of the channel. Both gating mechanisms are thought to interact allosterically. 3. K(+)-dependent gating was shown to be strictly coupled to pH gating; it only occurred when channels were in the pH-inactivated closed state, but not in the open state. Moreover, K(+)-dependent gating was absent in the non-pH-gated mutant K(ir)1.1(K80 M). 4. Channels inactivated by K(+)-dependent gating were reactivated upon addition of permeant ions to the extracellular side of the membrane, while impermeant ions failed to induce channel reactivation. Moreover, mutagenesis identified two residues in the P-helix (L136 and V140 in K(ir)1.1) that are crucial for K(+)-dependent gating. Replacement of these residues with the ones present in the non-K(+)-gated K(ir)2.1 abolished K(+)-dependent gating of K(ir)1.1 channels without affecting pH gating. 5. The results indicate that pH gating and K(+)-dependent gating are coupled to each other via structural rearrangements in the inner pore involving the P-helix.
Mycoparasitism by Three Species ofDiplococcium(Hyphomycetes)
2001-07-01

Abstract: The interactions between three species of Diplococcium and their respective host fungi were investigated using light and transmission electron microscopy. Two types of interactions were detected: D. clarkii and D. clavariarum, colonizing fruit bodies of basidiomycetes, produce appressoria with protrusions into the cell walls of the host fungi. The host reacts by apposition of secondary wall‐like material at the site of the interaction. Hyphae of D. parcum, a species reported from wood and bark, were encircled by hyphae of another fungus, probably belonging to a species of Tulasnella. Since D. parcum could not be cultivated in pure culture, this association between both fungi indicates that D. parcum was parasitic on hyphae of the presumed Tulasnella species.
Colacosiphon: A New Genus Described for a Mycoparasitic Fungus
2001-07-01

An undescribed heterobasidiomycetous fungus was found in cultures originating from bark beetles placed onto a natural medium. Spores were borne apically on extraordinarily long, filiform, aseptate structures arising from swollen hyphal cells. Within these cells, parasitic interactions with hyphae of an unidentified ascomycete by colacosomes were found. The septal pores of the parasitic fungus were simple and associated with microbodies containing inclusions similar to those of Woronin bodies. The fungus is closely related to Cryptomycocolax abnormis, the single species of the hitherto monotypic order Cryptomycocolacales. The undescribed fungus differs from C. abnormis by the presence of only one type of colacosome, the absence of clamps, and the absence of a transversely septate stage during sporogenesis. A new genus and species is proposed for the undescribed fungus: Colacosiphon filiformis. Since it is not clear whether the unusual sporogenous structures are conidiophores or basidia, the new taxon was preliminarily considered as anamorphic.
An Expeditious Synthesis of Optically Pure 1,4,5,6-Tetrahydro-as-Triazines, Fused to the Carbohydrate Skeleton
2001-07-01

Abstract An easy and high yield one pot reaction to enantiomerically pure 1,4,5,6-tetrahydro-as-triazines 5a–d and 8a–d is described, starting from benzyl 4-amino-2,3-anhydro-4-deoxy-β-l-lyxopyranoside (3) and benzyl 4-amino-2,3-anhydro-4-deoxy-α-d-lyxopyranoside (6).
Collidinium- und Imidazolium-Salze Fluor-haltiger Anionen. Die Kristallstruktur von [CollH]2 [AsF6][As2 F11] (Coll = 2,4,6-Trimethylpyridin) / Collidinium and Imidazolium Salts of Fluorine-Containing Anions. The Crystal Structure of [CollH]2[AsF6][As2F11] (Coll = 2,4,6-Trimethylpyridine)
2001-07-01

Abstract Die Kristall struktur von [CollH] 2 [AsF 6 ][As 2 F 11 ] (Coll = 2,4,6-Trimethylpyridin) Collidinium and Imidazolium Salts of Fluorine-Containing Anions. The Crystal Structure of [CollH] 2 [AsF 6 ][As 2 F 11 ] (Coll = 2,4,6-Trimethylpyridine) From s-Collidine (1, Coll) and aqueous HF compounds of the composition Coll · n HF (n = 1 -2) are formed which are transformed to [CollH] + [HF 2 ] - (2) by sublimation. [CollH] 2 [AsF 6 ][As 2 F] J (3) is obtained from 1 and the superacid system HF/AsF5. 2 reacts with 2,3-dihydro-l,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4, Im) to give the imidazo lium salt [ImH] + [HF 2 ] - (5). Hydrogen bonds in the crystal structure of [CollH] 2 [AsF 6 ][As 2 Fn ] (3) are discussed.
Banks, Financial Liberalisation and Financial Crises in Emerging Markets
2001-07-01

In 1991, Argentina, Brazil, Paraguay and Uruguay decided to establish a Mercado Comun del Sur (MERCOSUR). The new regional agreement developed quickly during the first half of the 90s and after a series of progressive tariff (and non‐tariff) reductions it became an (incomplete) customs union in 1995. During the second half of the 90s the completion of the customs union ran into increasing trouble and progress in the formation of a common market could not be realised. In this paper, two basic explanations of the poor performance of Mercosur are discussed. The first one claims that the adverse international situation (Asian crisis) is the main reason for the recent crisis. Consequently, a normalisation of the international environment is expected to be sufficient to revitalise the integration process. The second proposition emphasises more fundamental deficiencies of the concept of ‘open regionalism’. It is argued, that ‘open regionalism’ is inherently instable because, over time, it facilitates a more efficient articulation of vested interests working against ‘openness’. Proceeding from a simple free trade agreement (or a customs union) towards a common market tends to aggravate these problems. The conclusion of the paper is that the main obstacles to further regional integration in the Southern Cone are endogenous rather than exogenous. Therefore, the normalisation of the international economic environment may not be a sufficient condition for the revitalisation of the integration process.
Phosphoenolpyruvate carboxylase in mistletoe leaves: Regulation of gene expression, protein content, and covalent modification
2001-07-01

Seasonal changes in the activity of phospho enol pyruvate carboxylase (PEPCase, EC 4.1.1.31), a key enzyme in the interaction of carbohydrate and nitrogen metabolism, were studied in leaves of the C 3 semiparasitic mistletoe, Viscum album, growing on different host trees. Maximum extractable PEPCase activities were higher in leaves of mistletoes growing on Betula pendula and Alnus glutinosa hosts compared with those on the conifers, Abies alba and Larix decidua . Independent of host, maximum extractable PEPCase activities were high in spring and autumn while low in summer. Samples with higher PEPCase activities showed higher amounts of PEPCase protein and higher PEPCase mRNA levels. A curvilinear correlation between leaf total nitrogen content and the maximum extractable PEPCase activity as well as PEPCase mRNA level suggested that nitrogen might affect the activity of PEPCase of mistletoe by up‐regulating gene expression. In addition to extractable activity, seasonal changes of the PEPCase activation state, the ratio of activities resulting from limited:non‐limited assays, were found, which was correlated to the variation of malate content in leaves of mistletoe. ATP‐dependent activation of PEPCase was characterized by an increase in I 0.5 ( l ‐malate), indicating that PEPCase of leaves of mistletoes is probably regulated via phosphorylation.
The peptide-specific alloreactive human T cell repertoire varies largely between individuals and is not extended in HLA-A*0205–anti-HLA-A*0201 pairings
2001-07-01

Alloreactive T cells recognize framework or peptide-dependent determinants on foreign MHC molecules. Among the peptide-dependent alloreactive T cells a significant proportion is specific for one particular peptide presented by the allo-MHC molecule as antigen-specific T cells would do. Such alloreactive, peptide-specific T cells are referred to as 'allorestricted'. High-avidity HLA-A*02 allorestricted cytotoxic T lymphocyte (CTL) clones specific for peptide libraries can be generated from HLA-A*02(-) donors. We made use of this technique to study the role of closely related self-HLA molecules on shaping of the alloreactive T cell repertoire. Peripheral blood lymphocytes from HLA-A*0205 individuals were stimulated by HLA-A*0201 targets pulsed with an HLA-A*0201 peptide library. We did not observe a bias towards peptide-specific CTL in the HLA-A*0201-directed alloreactive repertoire of HLA-A*0205 donors as compared to HLA-A*02(-) donors. Comparison of the alloreactive T cell response between two donors having similar HLA haplotypes demonstrated that the allorestricted T cell repertoire is largely different between individuals.
Assessment of denaturing high‐performance liquid chromatography (DHPLC) in screening for mutations in connexin 26 (GJB2)
2001-07-01

Mutations in the gene GJB2 encoding connexin 26 (Cx26), a gap junction protein, have been shown to be responsible for a majority of recessive nonsyndromic hereditary hearing impairment in children. Over 60 different mutations in Cx26 have been reported. To obviate the need for direct sequencing of each specimen, a variety of screening techniques have been used to detect mutations in Cx26. However, each of these methods has significant shortcomings including expense, time consumption, and limited sensitivity. Denaturing high-performance liquid chromatography (DHPLC) has been recently introduced as a rapid and highly sensitive method of detecting sequence alterations. We have assessed the efficacy of DHPLC as a screening assay for detecting mutation in Cx26 coding region in 154 patients with hereditary hearing impairment. The GJB2 coding exon was amplified in one or two fragments, analyzed by DHPLC, and sequenced. Sequence analysis identified sequence variations in 34 patients concordant with abnormal DHPLC results. Three novel Cx26 mutations were identified: a single base pair substitution 511G>A, a 4 bp insertion 504insAACG, and a 3 bp deletion 358delAGG in three unrelated patients. In 120 patients with normal Cx26 sequence, DHPLC was normal. These results yield sensitivity and specificity of 100% for DHPLC-based detection of Cx26 mutations, and demonstrate that DHPLC is a highly sensitive and specific method of screening for sequence variations in Cx26 that is time and labor efficient. Further, our experience suggests that DHPLC screening alone followed by DNA sequencing only when DHPLC is abnormal may be adequate for identification of all sequence alterations in Cx26. Hum Mutat 18:42–51, 2001. © 2001 Wiley-Liss, Inc.
Can LSND be included in a three-neutrino framework?
2001-07-02

We study the special features emerging from a three lepton generation analysis of the available neutrino oscillation data (solar, atmospheric and LSND). First we find that it is possible to explain all three sets of data in terms of the standard left handed neutrinos without the need of sterile neutrinos. Second we find a significant difference in the mass matrix extracted from the data, depending on the analysis (without or with LSND), if the mass of the lightest neutrino, which cannot be determined from the neutrino oscillation data alone, is relatively small, i.e 0.1 eV. To compare with other processes we used the R-parity violating Minimal Supersymmetric Standard Model (\\rp-MSSM) for the theoretical description of the neutrino masses. Using the oscillation data we were able to constrain the parameters of the model. In particular we were able to obtain values for the coupling constants of the \\rp-MSSM.
Recognition of Governments in International Law
2001-07-05

Abstract This book studies the recognition of governments in international law. It is based on an analysis of the diplomatic practice of states as well as decisions by national and international courts. It explores the two central questions of the recognition of governments: what are the meanings of the term ‘recognition’ and its variants in international law such as de facto, de jure, and diplomatic recognition?; and what is the effect of such recognition on the legal status of foreign authorities, and in particular, of governments in exile? Along the lines of these questions the study is organized in a general introduction and two main parts which are followed by three appendices: replies received from various states in response to a questionnaire on the recognition of governments, short profiles of authorities in exile claiming to be ‘governments’, and a list of treaties concluded by authorities in exile recognized as governments. The book is comprehensive in its analysis of the issues, and covers material of historical interest, as well as recent developments in Angola, Kuwait, and Haiti.
Off-shell behavior of the in-medium nucleon-nucleon cross section
2001-07-06

The properties of nucleon-nucleon scattering inside dense nuclear matter are investigated. We use the relativistic Brueckner-Hartree-Fock model to determine on-shell and half off-shell in-medium transition amplitudes and cross sections. At finite densities the on-shell cross sections are generally suppressed. This reduction is, however, less pronounced than found in previous works. In the case that the outgoing momenta are allowed to be off energy shell the amplitudes show a strong variation with momentum. This description allows to determine in-medium cross sections beyond the quasi-particle approximation accounting thereby for the finite width which nucleons acquire in the dense nuclear medium. For reasonable choices of the in-medium nuclear spectral width, i.e. MeV, the resulting total cross sections are, however, reduced by not more than about 25% compared to the on-shell values. Off-shell effect are generally more pronounced at large nuclear matter densities.
Pharmacokinetics of Levetiracetam and Its Enantiomer (R)‐α‐ethyl‐2‐oxo‐pyrrolidine acetamide in Dogs
2001-07-07

Summary: Purpose: The new antiepileptic drug, levetiracetam (LEV, ucb LO59), is a chiral molecule with one asymmetric carbon atom whose anticonvulsant activity is highly enantioselective. The purpose of this study was to evaluate and compare the pharmacokinetics (PK) of LEV [(S)‐α‐ethyl‐2‐oxo‐pyrrolidine acetamide] and its enantiomer (R)‐α‐ethyl‐2‐oxo‐pyrrolidine acetamide (REV) after i.v. administration to dogs. This is the first time that the pharmacokinetics of both enantiomers has been evaluated. Methods: Optically pure LEV and REV were synthesized, and 20 mg/kg of individual enantiomers was administered intravenously to six dogs. Plasma and urine samples were collected until 24 h, and the concentrations of LEV and REV were determined by an enantioselective assay. The levels of 2‐pyrrolidone‐ N ‐butyric acid, an acid metabolite of LEV and REV, were determined by high‐performance liquid chromatography (HPLC). The data were used for PK analysis of LEV and REV. Results: LEV and REV had similar mean ± SD values for clearance; 1.5 ± 0.3 ml/min/kg and volume of distribution; 0.5 ± 0.1 L/kg. The half‐life (t 1/2 ) and mean residence time (MRT) of REV (t 1/2 , 4.3 ± 0.8 h, and MRT, 6.0 ± 1.1 h) were, however, significantly longer than those of LEV (t 1/2 , 3.6 ± 0.8 h, and MRT, 5.0 ± 1.2 h). The renal clearance and fraction excreted unchanged for LEV and REV were significantly different. Conclusions: In addition to the enantioselective pharmacodynamics, α‐ethyl‐2‐oxo‐pyrrolidine acetamide has enantioselective PK. The enantioselectivity was observed in renal clearance. Because REV has more favorable PK in dogs than LEV, the higher antiepileptic potency of LEV is more likely due to intrinsic pharmacodynamic activity rather than to enantioselective PK.
Evolution strategy with neighborhood attraction – a robust evolution strategy
2001-07-07

The evolution strategy with neighborhood attraction (EN) is a new combination of self-organizing maps (SOM) and evolution strategies (ES). It adapts the neighborhood relationship known from SOM to ES individuals in order to concentrate them around the optimum of the problem. In this paper, detailed investigations on the robustness of the EN were performed on a variety of well-known optimization problems. The behavior of the EN was compared to that of several other known variants of ES such as ES with mutative step control, ES with covariance matrix adaptation, differential evolution and others. In this test series, it was shown that EN is much more robust than the other ES variants.
Early left periventricular brain lesions induce right hemispheric organization of speech
2001-07-10

Right-hemispheric organization of speech has been observed following early left-sided brain lesions involving the language cortex. The authors studied speech organization in hemiparetic patients with pre- and perinatally acquired lesions in the left periventricular white matter using fMRI, and found that right-hemisphere activation correlated with left facial motor tract involvement. This suggests that the impairment of speech motor output from the left hemisphere plays an important role in this alteration of language representation.
Evidence that an Additional Mutation Is Required To Tolerate Insertional Inactivation of theStreptomyces lividans recAGene
2001-07-15

ABSTRACT In contrast to recA of other bacteria, the recA gene of Streptomyces lividans has been described as indispensable for viability (G. Muth, D. Frese, A. Kleber, and W. Wohlleben, Mol. Gen. Genet. 255:420–428, 1997.). Therefore, a closer analysis of this gene was performed to detect possible unique features distinguishing the Streptomyces RecA protein from the well-characterized Escherichia coli RecA protein. The S. lividans recA gene restored UV resistance and recombination activity of an E. coli recA mutant. Also, transcriptional regulation was similar to that of E. coli recA . Gel retardation experiments showed that S. lividans recA is also under control of the Streptomyces SOS repressor LexA. The S. lividans recA gene could be replaced only by simultaneously expressing a plasmid encoded recA copy. Surprisingly, the recA expression plasmid could subsequently be eliminated using an incompatible plasmid without the loss of viability. Besides being UV sensitive and recombination deficient, all the mutants were blocked in sporulation. Genetic complementation restored UV resistance and recombination activity but did not affect the sporulation defect. This indicated that all the recA mutants had suffered from an additional mutation, which might allow toleration of a recA deficiency.
Coupled multifield formulation for ionic polymer gels in electric fields
2001-07-16

In this paper, electrolyte polymer gels, consisting of a polymer network with ionizable groups and a liquid phase with mobile ions, are investigated. For these gels, we present a volume- and surface-coupled multi-field problem involving chemo-electro-mechanics. First, we derive a convection-diffusion equation for the ion concentrations inside and outside the gel as well as a Laplace equation for the electric field. Second, an equation of motion in order to simulate the unsteady swelling-behavior of the gels, is presented. For the chemo-electro-mechanical coupling, the equations as well as the solution scheme, are given. For the numerical simulation, unconditionally stable, higher order accurate, conservative and implicit space-time finite elements with interpolations - continuous in space and discontinuous in time - are used. We investigate the anionic and the cationic ion concentrations for a given fixed number of bound anionic groups as well as the electric potential inside and outside the gel at a given electric field. The resulting increase in the Donnan potential difference on the anode side of the gel, which represents the higher swelling rate, is in good agreement with experimental results. This shows the validity and the potential of the model.
Electrochemical stimulation and control of electroactive polymer gels
2001-07-16

Direct effects of electrical currents on polyelectrolyte gels are always associated with changes in their Donnan potential. Thus electrical stimulation of gels can be only completely understood if the direct effect of electric fields on the potential profile within the gels are known. The purpose of this study is to present recordings of Donnan potentials in electroactive gels of various compositions, especially under the influence of electric fields. An important finding is that opposite alterations in the Donnan potential simultaneously occur at the current inflow and outflow region of the gel. In anionic gels hyperpolarization, i.e. higher negativity, is induced on the anode-side of the gel, whereas depolarization is found on the cathode-side. As these shifts in the potential are supposed to affect swelling or deswelling of polyelectrolyte gels, they will primarily promote bending motions of the gel. To demonstrate the opposite bending behavior of anionic and cationic polymer gels under the influence of an electric field a short video sequence of an EAP gripper in action is presented. It is made exclusively of polyelectrolyte gel strips taking advantage of the fact that anionic and cationic polyacrylamide gels can be attached firmly to each other without any adhesive.
“Electronic nose” detects major histocompatibility complex-dependent prerenal and postrenal odor components
2001-07-17

Mice prefer to mate with individuals expressing different MHC genes from their own. Volatile components presenting MHC-dependent odor types are present in urine and can be detected by mice, as shown by extensive behavioral studies. Similar odor types are suspected to influence human behavior as well. Although a recent report indicates that MHC expression influences the ratio of volatile compounds such as phenylacetic acid, so far no other means than studying the behavior of mice or rats has been available to assess odor types. Here, we report the ability of a gas sensor array (referred to as “electronic nose”) to detect MHC-dependent odor types. The electronic nose consists of an array of chemophysical detectors, in our case quartz crystal microbalances and semiconducting metal-oxide sensors that change frequency or conductivity upon binding of very small numbers of individual molecules present in the gas phase of odorous fluids. The pattern of changes is characteristic for a particular smell. Our electronic nose distinguishes the urine odor types of MHC congenic mouse strains, MHC class I mutant mice, and HLA-A2 transgenic mice. In addition, MHC-dependent odor types can be detected in serum. The device also clearly differentiates between individual odor types of human sera from HLA homozygous individuals; however, HLA expression seems to have only a secondary influence. Thus, odor-type research can now be carried out with an objective and fast through-put system independent of behavioral studies.