Effects of two loop contributions in the pseudofermion functional renormalization group method for quantum spin systems

We implement an extension of the pseudofermion functional renormalization group method for quantum spin systems that takes into account two loop diagrammatic contributions. An efficient numerical treatment of the additional terms is achieved within a nested graph construction which recombines different one loop interaction channels. In order to be fully self consistent with respect to self energy corrections, we also include certain three loop terms of Katanin type. We first apply this formalism to the antiferromagnetic J1 amp; 8722;J2 Heisenberg model on the square lattice and benchmark our results against the previous one loop plus Katanin approach. Even though the renormalization group RG equations undergo significant modifications when including the two loop terms, the magnetic phase diagram, comprising N el ordered and collinear ordered phases separated by a magnetically disordered regime, remains remarkably unchanged. Only the boundary position between the disordered and the collinear phases is found to be moderately affected by two loop terms. On the other hand, critical RG scales, which we associate with critical temperatures Tc, are reduced by a factor of 2 indicating that the two loop diagrams play a significant role in enforcing the Mermin Wagner theorem. Improved estimates for critical temperatures are also obtained for the Heisenberg ferromagnet on the three dimensional simple cubic lattice where errors in Tc are reduced by 34 . These findings have important implications for the quantum phase diagrams calculated within the previous one loop plus Katanin approach which turn out to be already well converge

Introduction of Substituents on the 2-Oxo-piperazine Skeleton by [3+2] Cycloaddition and Subsequent Transformation

The 3,4-substituted 2-oxo-piperazines 5 - 9 are obtained by [3+2] cycloaddition from nitrone 1 and a variety of alkenes. Subsequent functionalization of the bicyclic adducts involves reductive N-O bond cleavage. A route towards libraries of immobilized 1,3-aminoalcohols with a 3,4-substituted 2-oxo-piperazine scaffold is briefly discussed for adducts derived from N-substituted maleic imide

The Manin constant of elliptic curves over function fields

We study the p-adic valuation of the values of normalised Hecke eigenforms attached to non-isotrivial elliptic curves defined over function fields of transcendence degree one over finite fields of characteristic p. We derive upper bounds on the smallest attained valuation in terms of the minimal discriminant under a certain assumption on the function field and provide examples to show that our estimates are optimal. As an application of our results we also prove the analogue of the degree conjecture unconditionally for strong Weil curves with square-free conductor defined over function fields satisfying the assumption mentioned above.Comment: 31 pages, to appear in Algebra and Number Theor

A palaeolimnological study of Tugulnuit Lake, British Columbia, Canada, with special emphasis on river influence as recorded by chironomids in the lake's sediment

Sediments from Tugulnuit Lake in the Okanagan Valley of British Columbia, Canada, were examined for chironomid assemblages. The chironomid stratigraphy obtained encompasses the last 4000 to 5000 years and suggests a warm and fairly stable climate typical for a temperate lake at low- to mid-elevation. This is indicated by the even distribution of warm-water taxa, such as Cladopelma, Dicrotendipes, Polypedilum, Pentaneurini, Stempellina, Stempellinella/Zavrelia and Pseudochironomus throughout the core. Very few cold-water taxa occurred in the sediments. However, stream inputs have had a major impact on Tugulnuit Lake. Sandy sediments and the appearance of Simuliidae and stream-inhabiting chironomid taxa (e.g., Brillia/Euryhapsis, Eukiefferiella/Tvetenia, Rheocricotopus) indicate that a stream intruded into the current lake's basin ca. 3800 yr Before Present (BP). Sediments deposited prior to, and after, the stream's intrusion show a distinctly different chironomid assemblage exhibiting chironomid taxa more typical for lentic habitats. This result indicates that chironomids can serve to detect past stream influences on lake environments. Thus, rheophilic chironomids preserved in lake cores provide a new alternative for reconstructing stream palaeoenvironmental record

Capsulotomy in anxiety disorders

Background Anxiety disorders are common and a substantial proportion of patients do not respond to conventional treatments such as SSRIs or CBT. Capsulotomy is a neurosurgical treatment for treatment refractory patients with Obsessive-Compulsive Disorder (OCD) and other anxiety disorders. The aim of this thesis was to assess the long-term efficacy and safety of capsulotomy. Methods and results In Study I, 26 consecutive patients who underwent capsulotomy from 1975-1991 were followed after a mean of 13 years. Main diagnoses were Generalized Anxiety Disorder (n=13), Panic Disorder (n=8) and Social Phobia (n=5). Mean Brief Scale of Anxiety score dropped significantly from preoperative 22 to 10 at long-term. Seven patients had postoperative problems in the domains of executive functioning, apathy or disinhibition. Mean weight gain in the first postoperative year was almost 10 kg. Study II and III were substudies of Study I. In Study II the capsulotomy lesion size and localization in the anterior-posterior plane was analyzed. We could not replicate previous findings of a common anatomical denominator in the right-sided capsule in patients responding to the treatment. In Study III, we used a self-rated personality inventory, the Karolinska Scales of Personality, to describe changes pre- to postoperatively in self-rated personality. Patients were significantly less anxiety prone at follow-up. Study IV was a long-term follow-up of 25 consecutive OCD capsulotomies performed 1988 -2000. Mean Y-BOCS was 34 preoperatively and dropped to 18 at long-term follow-up (p<0.0001). Only 2 patients achieved remission from OCD without substantial side effects. Several neurosurgical complications related to radiosurgery were reported.Two patients were severely disinhibited postoperatively. Ten patients were considered to suffer from significant problems in the area of executive functioning, apathy or disinhibition. Global functioning did not return to normal after surgery. Lesion size did not correlate significantly with efficacy or adverse effects. Conclusions Capsulotomy is effective in reducing symptoms in both OCD and other anxiety disorders. About every third patient experienced apathy, executive problems or disinhibition at long-term follow up, therefore we conclude that capsulotomy is not a safe procedure. We could not identify lesion characteristics that could explain the differences in outcome. We could not confirm the hypothesis of a certain right-sided lesion as a prerequisite for response to capsulotomy

Synthesis and evaluation of novel picolinic acid-based bispidine ligands and their metal complexes for the application in nuclear medicine

Defeating cancer is one of the major challenges that humankind is facing today. To this end, nuclear medicine offers promising approaches including radiometal-based pharmaceuticals. The work presented in this thesis focused on the development of new ligand systems for application as metal-chelating units in radiopharmaceuticals. These novel ligands were evaluated in various non-radioactive and radioactive metal complexation studies concerning their potential application in nuclear medicine

Development, characterization and miniaturization of a trace gas detection system for NO₂ in air based on photoacoustic spectroscopy

This thesis provides a detailed theoretical discussion about common absorption spectroscopy (AS) and, in particular, about photoacoustic spectroscopy (PAS). The physical concepts of signal generation are illustrated in view of amplitude modulation (AM) and wavelength modulation (WM). Furthermore the advantages and disadvantages of the techniques are presented. As a result, PAS was identified to outclass AS, thus it turned out to be the method of choice in view of developing a miniaturized trace gas sensing application. The theoretical part of this work further outlines various approaches of signal enhancement, e.g. by acoustic and/or mechanical resonance amplification. Besides, several phenomena of signal attenuation are addressed, e.g. acoustic detuning, vibrational-translational (VT) relaxation and vibrational-vibrational (VV) energy transfer processes, which have to be considered with regard to the individual measuring conditions. Simulation and experimental chapters illustrate the pre-development and the practical implementation of a laboratory photoacoustic setup, a portable trace gas monitoring device and various photoacoustic cell (PAC) designs. These include a conventional bulky design, an optimized low-cost 3D printed PAC, a miniaturized quartz enhanced photoacoustic spectroscopic (QEPAS) scheme and a further integrated microelectromechanical system (MEMS) based sensor chip, respectively. Although several parts of this thesis also provide preparatory work for multi-component analysis, nitrogen dioxide (NO2) was used as primary analyte in order to characterize the above mentioned photoacoustic cell designs. This involves acoustic resonance and noise analysis, determination of optimal operating parameters (e.g. gas flow rate and lock-in time constant), performance evaluation (e.g. response behavior, optical performance, calibration characteristics and long-term signal stability) as well as interference studies towards oxygen (O2), carbon dioxide (CO2), humidity (H2O) and acoustic noise. In conclusion, NO2 detection by means of the low-cost 3D printed PAC and the QEPAS configuration even revealed two world record detection limits (1sigma) of 33 pptV and 600 pptV, respectively

Complexes between kinases, mitochondrial porin and adenylate translocator in rat brain resemble the permeability transition pore

AbstractIn vitro incubation of isolated hexokinase isozyme I or isolated dimer of mitochondrial creatine kinase with the outer mitochondrial membrane pore led to high molecular weight complexes of enzyme oligomers. Similar complexes of hexokinase and mitochondrial creatine kinase could be extracted by 0.5% Triton X-100 from homogenates of rat brain. Hexokinase and creatine kinase complexes could be separated by subsequent chromatography on DEAE anion exchanger. The molecular weight, as determined by gel-permeation chromatography, was approximately 400 kDa for both complexes. The Mr suggested tetramers of hexokinase (monomer 100 kDa) and creatine kinase (active enzyme is a dimer of 80 kDa). The composition of the complexes was further characterised by specific antibodies. Besides either hexokinase or creatine kinase molecules the complexes contained porin and adenylate translocator. It was possible to incorporate the complexes into artificial bilayer membranes and to measure conductance in 1 M KCl. The incorporating channels had a high conductance of 6 nS that was asymmetrically voltage dependent. The complexes were also reconstituted in phospholipid vesicles that were loaded with ATP. Complex containing vesicles retained ATP while vesicles reconstituted with pure porin were leaky. The internal ATP could be used by creatine kinase and hexokinase in the complex to phosphorylate external creatine or glucose. This process was inhibited by atractyloside. The hexokinase complex containing vesicles were furthermore loaded with malate or ATP that was gradually released by addition of Ca2+ between 100 and 600 μM. The liberation of malate or ATP by Ca2+ could be inhibited by N-methylVal-4-cyclosporin, suggesting that the porin translocator complex constitutes the permeability transition pore. The results show the physiological existence of kinase porin translocator complexes at the mitochondrial surface. It is assumed that such complexes between inner and outer membrane components are the molecular basis of contact sites observed by electron microscopy. Kinase complex formation may serve three regulatory functions, firstly regulation of the kinase activity, secondly stimulation of oxidative phosphorylation and thirdly regulation of the permeability transition pore