The Far Eastern Question at the Washington Conference (1921-1922) with an outline of its implications for internal politics in China

This dissertation is a narrative account of the negotiations concerning the question of the Far East and the Shandong issue at the Washington Conference, leading to treaties, agreements and resolutions. In this dissertation, a certain stress is laid on the interaction between the Conference and the internal situation in China, particularly concerning the question of the implications of the Conference for Cabinet politics in Peking. Through the narrative account of the Conference, the general aim is an attempt to reassess the achievements of the Washington Conference. Too often the Washington Conference has been viewed negatively. The political aim behind the legal framework was to open the door to China as a sovereign State member of the international community whose territorial integrity was internationally recognized, despite its chaotic internal situation. It is undeniable that the Washington Conference opened a new chapter in modern Chinese history. The violations of the agreements concerning China that occurred in the 1930s should not lead to the belief that these agreements were of no value. Peace may not be lasting and evolves according to circumstances; agreements are transitory, and new situations need new arrangements. This dissertation tries to demonstrate that the agreements in themselves were not the cause of their failure, but the failure was due to the lack of determination on the part of the Signatories Powers to defend them.

Total synthesis of the fungal metabolite (+/-)-acremine G: acceleration of a biomimetic Diels-Alder reaction on silica gel

A total synthesis of the bioactive tetracyclic natural product acremine G has been achieved in which a regio- and stereoselective biomimetic Diels-Alder reaction between two readily assembled building blocks, accelerated on a solid support (silica gel), forms the key step. (c) 2010 Elsevier Ltd. All rights reserved.

Oppineiden talossa : Helsingin yliopiston slavistien kansainväliset verkostot Suomen Yliopistollisen Avustuskomitean toiminnan yhteydessä vuosina 1921-1925.

Tutkimuksessani tarkastelen kolmen Helsingin yliopiston slavistin, kirjastonhoitaja Andrei Igelströmin, kansan-runoudentutkija Viljo Johannes Mansikan ja kielentutkija Jooseppi Julius Mikkolan, kansainvälisiä tieteellisiä ja poliittisia verkostoja. Nämä verkostot muodostuivat venäläisten tiedemiesten avustamiseksi perustetun Suomen Yliopistollisen Avustuskomitean kansainvälisen toiminnan ja siihen keskeisesti liittyneiden venäläisten tieteellisten julkaisujen välityksen ja Helsingin yliopiston konsistorin alaisen Venäläisten kirjaston ostohankkeen ympärille vuosina 1921-1925. Tutkimuksessani olen pyrkinyt vastamaan kysymyksiin: Millaista kansainvälistä tieteellistä ja poliittista yh-teistyötä suomalaiset slavistit Avustuskomitean yhteydessä harjoittivat? Millaisia tavoitteita Igelström, Mansikka ja Mikkola asettivat Suomen Yliopistollisen Avustuskomitean toiminnalle? Millaisia poliittisia ja tieteellisiä toimintamuotoja Avustuskomitea slavistien ohjaamana sai, mitä ulkopuolisia tavoitteita avustustoimintaan liittyi, ja lopulta miten Avustuskomitean toiminta heijasteli kansainvälisen tieteellisen yhteistyön muutosta uudessa valtiollisessa tilanteessa 1920-luvun alussa? Aihettani olen jäsentänyt verkosto-käsitteen ja verkostoteorian mallien avulla. Keskeisiä lähteitä ovat olleet Igelströmin, Mansikan ja Mikkolan Avustusko-miteaa käsittelevä kirjeenvaihto, Avustuskomitean kirjanpito ja avustustoimintaan osallistuneiden yhteisöjen julkaisemattomat ja julkaistut raportit sekä muistiot. Tutkimuksessa on käytetty historiantutkimuksen mene-telmiä, ja se liittyy Helsingin yliopiston slaavilaisen filologian oppiaineen ja Venäläisen kirjaston historiaan. Tutkimus osoitti Igelströmin, Mansikan ja Mikkolan kansainvälisten tieteellisten verkostojen olleen ratkaisevassa asemassa Suomen Yliopistollisen Avustuskomitean muodostamisessa ja kansainvälisen avustustoiminnan järjestämisessä. Tieteellisistä verkostoista keskeisessä asemassa oli Pietarin Tiedeakatemian tieteellisten julkaisuiden myynti ja vaihto. Painotuotteiden vaihto länsimaisten tieteellisten instituuttien kanssa järjestettiin Venäläisen kirjaston ja sen kirjastonhoitajan Andrei Igelströmin välityksellä. Vuosina 1921 1923 Igelströmin hallinnoima vaihtokeskus oli kansainvälisesti ainutlaatuinen ja rakensi uudelleen tieteellisen yhteistyön Suomen ja Venäjän välille sekä loi edellytyksiä kansainvälisen tiedeyhteistyön elvyttämiselle venäläisen tiedeyhteisön kanssa. Poliittisten verkostojen näkökulmasta suomalaisten slavistien kontaktit T ekkoslovakian ulko-asianhallinnon kanssa paljastuivat läheisiksi ja yhteistyö ulottui avustustoiminnan lisäksi myös Suomen kau-pallisten etujen edistämiseen ja kysymykseen venäläisten emigranttien asemasta T ekkoslovakiassa 1920-luvun alkuvuosina. Venäläisten emigranttien asema Prahassa ja Suomen Yliopistollisen Avustuskomitean välinen yhteys konkretisoitui Venäläisen kirjaston ostohankkeessa. Kirjastonostohankkeen syyksi on tässä tutkimuksessa osoitettu T ekkoslovakian ulkoasianhallinnon action russe -politiikka ja T ekkoslovakian valtion pyrkimys luoda edellytyksiä uudelle tieteelliselle orientaatiolle, johon slavistisen tutkimuksen ja kielitieteiden kehitys 1920-luvun Prahassa liittyivät. Aloitteentekijöiksi kirjastonostohankkeeseen on osoitettu Helsingissä ja Prahassa toiminut ukrainalainen emigrantti Vladimir Tukalevski, joka yhdessä Igelströmin ja T ekkoslovakian varaulkoasiain-ministerin Václav Girsan kanssa suunnitteli Venäläisen kirjaston ostamista ja sen siirtämistä Prahaan.

C-H…O hydrogen bond mediated chain reversal in a peptide containing g-amino acid residue, determined directly from powder X-ray diffraction data

The finding that peptides containing -amino acid residues give rise to folding patterns hitherto unobserved in -amino acid peptides[1] has stimulated considerable interest in the conformational properties of peptides built from , and residues,[2] as the introduction of additional methylene (CH2) units into peptide chains provides further degrees of conformational freedom.

A nanosecond molecular dynamics study of antiparallel d(G)(7) quadruplex structures: Effect of the coordinated cations

Nanosecond scale molecular dynamics simulations have been performed on antiparallel Greek key type d(G(7)) quadruplex structures with different coordinated ions, namely Na+ and K+ ion, water and Na+ counter ions, using the AMBER force field and Particle Mesh Ewald technique for electrostatic interactions. Antiparallel structures are stable during the simulation, with root mean square deviation values of similar to1.5 Angstrom from the initial structures. Hydrogen bonding patterns within the G-tetrads depend on the nature of the coordinated ion, with the G-tetrad undergoing local structural variation to accommodate different cations. However, alternating syn-anti arrangement of bases along a chain as well as in a quartet is maintained through out the MD simulation. Coordinated Na+ ions, within the quadruplex cavity are quite mobile within the central channel and can even enter or exit from the quadruplex core, whereas coordinated K+ ions are quite immobile. MD studies at 400 K indicate that K+ ion cannot come out from the quadruplex core without breaking the terminal G-tetrads. Smaller grooves in antiparallel structures are better binding sites for hydrated counter ions, while a string of hydrogen bonded water molecules are observed within both the small and large grooves. The hydration free energy for the K+ ion coordinated structure is more favourable than that for the Na+ ion coordinated antiparallel quadruplex structure.

Effect of coordinated ions on structure and flexiblity of parallel G-quandruplexes: a molecular dynamics study

Single tract guanine residues can associate to form stable parallel quadruplex structures in the presence of certain cations. Nanosecond scale molecular dynamics simulations have been performed on fully solvated fibre model of parallel d(G7) quadruplex structures with Na+ or K+ ions coordinated in the cavity formed by the 06 atoms of the guanine bases. The AMBER 4.1 force field and Particle Mesh Ewald technique for electrostatic interactions have been used in all simulations. These quadruplex structures are stable during the simulation, with the middle four base tetrads showing root mean square deviation values between 0.5 to 0.8 A from the initial structure as well the high resolution crystal structure. Even in the absence of any coordinated ion in the initial structure, the G-quadruplex structure remains intact throughout the simulation. During the 1.1 ns MD simulation, one Na+ counter ion from the solvent as well as several water molecules enter the central cavity to occupy the empty coordination sites within the parallel quadruplex and help stabilize the structure. Hydrogen bonding pattern depends on the nature of the coordinated ion, with the G-tetrad undergoing local structural variation to accommodate cations of different sizes. In the absence of any coordinated ion, due to strong mutual repulsion, 06 atoms within G-tetrad are forced farther apart from each other, which leads to a considerably different hydrogen bonding scheme within the G-tetrads and very favourable interaction energy between the guanine bases constituting a G-tetrad. However, a coordinated ion between G-tetrads provides extra stacking energy for the G-tetrads and makes the quadruplex structure more rigid. Na+ ions, within the quadruplex cavity, are more mobile than coordinated K+ ions. A number of hydrogen bonded water molecules are observed within the grooves of all quadruplex structures

Molecular dynamics simulations on parallel and antiparallel C.G*G triplexes

Molecular dynamics (MD) studies have been carried out on the Hoogsteen hydrogen bonded parallel and the reverse Hoogsteen hydrogen banded antiparallel C.G*G triplexes. Earlier, the molecular mechanics studies had shown that the parallel structure was energetically more favourable than the antiparallel structure. To characterize the structural stability of the two triplexes and to investigate whether the antiparallel structure can transit to an energetically more favourable structure, due to the local fluctuations in the structure during the MD simulation, the two structures were subjected to 200ps of constant temperature vacuum MD simulations at 300K. Initially no constraints were applied to the structures and it was observed that for the antiparallel tripler, the structure showed a large root mean square deviation from the starting structure within the first 12ps and the N4-H41-O6 hydrogen bond in the WC duplex got distorted due to a high propeller twist and a moderate increase in the opening angle in the basepairs. Starting from an initial value of 30 degrees, helical twist of the average structure from this simulation had a value of 36 degrees, while the parallel structure stabilized at a twist of 33 degrees. In spite of the hydrogen bond distortions in the antiparallel tripler, it was energetically comparable to the parallel tripler. To examine the structural characteristics of an undistorted structure, another MD simulation was performed on the antiparallel tripler by constraining all the hydrogen bonds. This structure stabilized at an average twist of 33 degrees. In the course of the dynamics though the energy of the molecule - compared to the initial structure - improved, it did not become comparable to the parallel structure. Energy minimization studies performed in the presence of explicit water and counterions also showed the two structures to be equally favourable energetically Together these results indicate that the parallel C.G*G tripler with Hoogsteen hydrogen bonds also represents a stereochemically and energetically favourable structure for this class of triplexes.

Conformational Polymorphism in G-tetraplex Structures: Strand Reversal by Base Flipover or Sugar Flipover

Guanine rich sequences adopt a variety of four stranded structures, which differ in strand orientation and conformation about the glycosidic bond even though they are all stabilised by Hoogsteen hydrogen bonded guanine tetrads. Detailed model building and molecular mechanics calculations have been carried out to investigate various possible conformations of guanines along a strand and different possible orientations of guanine strands in a G-tetraplex structure. It is found that for an oligo G stretch per se, a parallel four stranded structure with all guanines in anti conformation is favoured over other possible tetraplex structures. Hence an alternating syn-anti arrangement of guanines along a strand is likely to occur only in folded back tetraplex structures with antiparallel G strands. Our study provides a theoretical rationale for the observed alternation of glycosidic conformation and the inverted stacking arrangement arising from base flipover, in antiparallel G-tetraplex structures and also highlights the various structural features arising due to different types of strand orientations. The molecular mechanics calculations help in elucidating the various interactions which stabilize different G-tetraplex structures and indicate that screening of phosphate charge by counterions could have a dramatic effect on groove width in these four stranded structures.

Double helix conformation, groove dimensions and ligand binding potential of a G/C stretch in B-DNA

The self-complementary DNA fragment CCGGCGCCGG crystallizes in the rhombohedral space group R3 with unit cell parameters a = 54.07 angstrom and c = 44.59 angstrom. The structure has been determined by X-ray diffraction methods at 2.2 angstrom resolution and refined to an R value of 16.7%. In the crystal, the decamer forms B-DNA double helices with characteristic groove dimensions: compared with B-DNA of random sequence, the minor groove is wide and deep and the major groove is rather shallow. Local base pair geometries and stacking patterns are within the range commonly observed in B-DNA crystal structures. The duplex bears no resemblance to A-form DNA as might have been expected for a sequence with only GC base pairs. The shallow major groove permits an unusual crystal packing pattern with several direct intermolecular hydrogen bonds between phosphate oxygens and cytosine amino groups. In addition, decameric duplexes form quasi-infinite double helices in the crystal by end-to-end stacking. The groove geometries and accessibilities of this molecule as observed in the crystal may be important for the mode of binding of both proteins and drug molecules to G/C stretches in DNA.