Insects Inhabiting the Burrows of the Ozark Pocket Gopher in Arkansas

Pocket gopher burrows provide a stable environment for a variety of inquilines; hence this mammal is regarded as a keystone species. Most of the arthropods inhabiting pocket gopher burrows are restricted to this microhabitat. As part of a planned state-wide biotic survey of insects inhabiting this unusual microhabitat, we have focused our initial sampling efforts on the Ozark pocket gopher (Geomys bursarius ozarkensis; Geomyidae). In 2004 and 2005, pitfall traps were established in pocket gopher burrows and in 2007 and 2008, nests and associated chambers were excavated. Retrieved samples contained scarab, histerid, and rove beetles, cave crickets and anthomyiid flies. The histerids consisted of five species, one of which is undescribed, and all of which are new state records. A total of five species of scarab beetles were collected and all of these represent new state records. Two species of cave crickets were collected; one appears to be undescribed, and the other is essentially a Great Plains species and represents a considerable range extension. Both crickets are new to Arkansas

Primjena tehnologije rekombinantne DNA za pripravke kolinesteraza kao antidota i detektora organofosfata

To develop new avenues for synthesizing novel antidotes for organophosphate poisoning and for detection of the organophosphates, we have turned to recombinant DNA methods to synthesize cholinesterases with unusual properties. For antidotal therapy we describe mutations of the native mouse and human enzymes that allow for enhanced rates of oxime reactivation. Such enzymes, when localized in the circulation, would enable the circulating cholinesterase to become a catalytic rather than simply a stoichiometric scavenger. Hence, “oxime-assisted catalysis” provides a means for scavenging the organophosphates in the circulation thereby minimizing their tissue penetration and toxicity. Accordingly, the oxime antidote or prophylactic agent has a dual action within the circulation and at the tissue level. Second, through a novel chemistry, termed freeze-frame, click chemistry, we have used organophosphate conjugates of acetylcholinesterase as templates for the synthesis of novel nucleophilic reactivating agents. Finally, acetylcholinesterase can be modified through cysteine substitution mutagenesis and attachment of fluorophores at the substitution positions. When linked at certain locations in the molecule, the attached fluorophore is sensitive to organophosphate conjugation with acetylcholinesterase, and thus the very target of insecticide or nerve agent action becomes a detection molecule for organophosphate exposure.Razvijajući novi pristup sintezi antidota pri otrovanju organofosfatima kao i njihovu detekciju, primijenili smo metode rekombinantne DNA za pripremu kolinesteraza s neuobičajenim svojstvima. Za antidotsku terapiju istražili smo mutacije prirodnih enzima miša i čovjeka koje povećavaju brzine reaktivacije oksimom. Takvi enzimi bi po unosu u cirkulaciju postali katalitički, a ne samo stehiometrijski odstranjivači organofosfata. Na taj način “oksimom potpomognuta kataliza” omogućava čišćenje organofosfata iz cirkulacije umanjujući prodiranje organofosfata u tkiva i njihovu toksičnost. Prema tome, oksim kao antidot ima dvojaku ulogu: u cirkulaciji i na razini tkiva. S druge strane, uporabom novog sintetskog pristupa u oblikovanju biološki aktivnih spojeva poznatog kao “klik kemija” diskretnih proteinskih konformacija, organofosforilirani konjugati acetilkolinesteraze služe kao kalup u sintezi novih nukleofilnih reaktivatora. Naposljetku, acetilkolinesteraza se može mutagenezom modificirati uvo|enjem cisteina na koje se mogu vezati fluorofori. Fluorofori uvedeni na određena mjesta u molekuli acetilkolinesteraze mijenjaju svoja fluorescentna svojstva pri konjugaciji organofosfata s enzimom koji na taj način od objekta djelovanja insekticida i živčanih bojnih otrova postaje molekula za detekciju izloženosti organofosfatima

CORE and the Haldane Conjecture

The Contractor Renormalization group formalism (CORE) is a real-space renormalization group method which is the Hamiltonian analogue of the Wilson exact renormalization group equations. In an earlier paper\cite{QGAF} I showed that the Contractor Renormalization group (CORE) method could be used to map a theory of free quarks, and quarks interacting with gluons, into a generalized frustrated Heisenberg antiferromagnet (HAF) and proposed using CORE methods to study these theories. Since generalizations of HAF's exhibit all sorts of subtle behavior which, from a continuum point of view, are related to topological properties of the theory, it is important to know that CORE can be used to extract this physics. In this paper I show that despite the folklore which asserts that all real-space renormalization group schemes are necessarily inaccurate, simple Contractor Renormalization group (CORE) computations can give highly accurate results even if one only keeps a small number of states per block and a few terms in the cluster expansion. In addition I argue that even very simple CORE computations give a much better qualitative understanding of the physics than naive renormalization group methods. In particular I show that the simplest CORE computation yields a first principles understanding of how the famous Haldane conjecture works for the case of the spin-1/2 and spin-1 HAF.Comment: 36 pages, 4 figures, 5 tables, latex; extensive additions to conten

The spectrum of COVID-19-associated dermatologic manifestations: an international registry of 716 patients from 31 countries

BACKGROUND: Coronavirus disease 2019 (COVID-19) has associated cutaneous manifestations. OBJECTIVE: To characterize the diversity of cutaneous manifestations of COVID-19, and facilitate understanding of underlying pathophysiology. METHODS: Case series from an international registry from the American Academy of Dermatology and International League of Dermatological Societies. RESULTS: The registry collected 716 cases of new-onset dermatologic symptoms in patients with confirmed/suspected COVID-19. Of the 171 patients in the registry with laboratory-confirmed COVID-19, the most common morphologies were morbilliform (22%), pernio-like (18%), urticarial (16%), macular erythema (13%), vesicular (11%), papulosquamous (9.9%), and retiform purpura (6.4%). Pernio-like lesions were common in patients with mild disease, while retiform purpura presented exclusively in ill, hospitalized patients. LIMITATIONS: We cannot estimate incidence or prevalence. Confirmation bias is possible. CONCLUSION: This study highlights the array of cutaneous manifestations associated with COVID-19. Many morphologies were non-specific, while others may provide insight into potential immune or inflammatory pathways in COVID-19 pathophysiology

Hardy's inequality for functions vanishing on a part of the boundary

We develop a geometric framework for Hardy's inequality on a bounded domain when the functions do vanish only on a closed portion of the boundary.Comment: 26 pages, 2 figures, includes several improvements in Sections 6-8 allowing to relax the assumptions in the main results. Final version published at http://link.springer.com/article/10.1007%2Fs11118-015-9463-

Analysis of Crystal Lattice Deformation by Ion Channeling

A model of dislocations has been developed for the use in Monte Carlo simulations of ion channeling spectra obtained for defected crystals. High resolution transmission electron microscopy micrographs show that the dominant type of defects in the majority of ion irradiated crystals are dislocations. The RBS/channeling spectrum is then composed of two components: one is due to direct scattering on randomly displaced atoms and the second one is related to beam defocussing on dislocations, which produce predominantly crystal lattice distortions, i.e. bent channels. In order to provide a correct analysis of backscattering spectra for the crystals containing dislocations we have modied the existing Monte Carlo simulation code McChasy. A new version of the code has been developed by implementing dislocations on the basis of the PeierlsNabarro model. Parameters of the model have been determined from the high resolution transmission electron microscopy data. The newly developed method has been used to study the Ar-ion bombarded SrTiO3 samples. The best t to the Rutherford backscattering/channeling spectra has been obtained by optimizing the linear combination of two kinds of defects: displaced atoms and bent channels. The great virtue of the Monte Carlo simulation is that unlike a traditional dechanneling analysis it allows quantitative analysis of crystals containing a mixture of dierent types of defects

Diagonalization in Reduced Hilbert Spaces using a Systematically Improved Basis: Application to Spin Dynamics in Lightly Doped Ladders

A method is proposed to improve the accuracy of approximate techniques for strongly correlated electrons that use reduced Hilbert spaces. As a first step, the method involves a change of basis that incorporates exactly part of the short distance interactions. The Hamiltonian is rewritten in new variables that better represent the physics of the problem under study. A Hilbert space expansion performed in the new basis follows. The method is successfully tested using both the Heisenberg model and the $t-J$ model with holes on 2-leg ladders and chains, including estimations for ground state energies, static correlations, and spectra of excited states. An important feature of this technique is its ability to calculate dynamical responses on clusters larger than those that can be studied using Exact Diagonalization. The method is applied to the analysis of the dynamical spin structure factor $S(q,\omega)$ on clusters with $2 \times 16$ sites and 0 and 2 holes. Our results confirm previous studies (M. Troyer, H. Tsunetsugu, and T. M. Rice, Phys. Rev. $B 53$, 251 (1996)) which suggested that the state of the lowest energy in the spin-1 2-holes subspace corresponds to the bound state of a hole pair and a spin-triplet. Implications of this result for neutron scattering experiments both on ladders and planes are discussed.Comment: 9 pages, 8 figures, Revtex + psfig; changed conten

Towards Measuring the Stop Mixing Angle at the LHC

We address the question of how to determine the stop mixing angle and its CP-violating phase at the LHC. As an observable we discuss ratios of branching ratios for different decay modes of the light stop ~t_1 to charginos and neutralinos. These observables can have a very strong dependence on the parameters of the stop sector. We discuss in detail the origin of these effects. Using various combinations of the ratios of branching ratios we argue that, depending on the scenario, the observable may be promising in exposing the light stop mass, the mixing angle and the CP phase. This will, however, require a good knowledge of the supersymmetric spectrum, which is likely to be achievable only in combination with results from a linear collider.Comment: 30 pages, 11 figures, version to appear in EPJ

Cholinesterases: Structure, Role, and Inhibition

Acetilkolinesteraza (AChE; E.C. 3.1.1.7) i butirilkolinesteraza (BChE; E.C. 3.1.1.8) enzimi su koji se zbog svoje uloge u organizmu intenzivno istražuju unutar područja biomedicine i toksikologije. Iako strukturno homologni, ovi enzimi razlikuju se prema katalitičkoj aktivnosti, odnosno specifi čnosti prema supstratima koje mogu hidrolizirati te selektivnosti za vezanje mnogih liganada. U ovom radu dan je pregled dosadašnjih istraživanja kolinesteraza i njihovih interakcija s ligandima i inhibitorima te su izdvojene aminokiseline aktivnog mjesta koje sudjeluju u tim interakcijama.Enzymes acetylcholinesterase (AChE; E.C. 3.1.1.7) and butyrylcholinesterase (BChE; E.C. 3.1.1.8) have intensively been investigated in biomedicine and toxicology due to important role in organisms. Even if structurally homologous, they differ in catalytic activity, specificity, for substrates, and selectivity in binding to many ligands. This paper compiles the results of research on cholinesterases and their interactions with ligands and inhibitors, and identifies amino acids of active sites involved in these interactions

TLR2, but Not TLR4, Is Required for Effective Host Defence against Chlamydia Respiratory Tract Infection in Early Life

Chlamydia pneumoniae commonly causes respiratory tract infections in children, and epidemiological investigations strongly link infection to the pathogenesis of asthma. The immune system in early life is immature and may not respond appropriately to pathogens. Toll-like receptor (TLR)2 and 4 are regarded as the primary pattern recognition receptors that sense bacteria, however their contribution to innate and adaptive immunity in early life remains poorly defined. We investigated the role of TLR2 and 4 in the induction of immune responses to Chlamydia muridarum respiratory infection, in neonatal wild-type (Wt) or TLR2-deficient (−/−), 4−/− or 2/4−/− BALB/c mice. Wt mice had moderate disease and infection. TLR2−/− mice had more severe disease and more intense and prolonged infection compared to other groups. TLR4−/− mice were asymptomatic. TLR2/4−/− mice had severe early disease and persistent infection, which resolved thereafter consistent with the absence of symptoms in TLR4−/− mice. Wt mice mounted robust innate and adaptive responses with an influx of natural killer (NK) cells, neutrophils, myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells, and activated CD4+ and CD8+ T-cells into the lungs. Wt mice also had effective production of interferon (IFN)γ in the lymph nodes and lung, and proliferation of lymph node T-cells. TLR2−/− mice had more intense and persistent innate (particularly neutrophil) and adaptive cell responses and IL-17 expression in the lung, however IFNγ responses and T-cell proliferation were reduced. TLR2/4−/− mice had reduced innate and adaptive responses. Most importantly, neutrophil phagocytosis was impaired in the absence of TLR2. Thus, TLR2 expression, particularly on neutrophils, is required for effective control of Chlamydia respiratory infection in early life. Loss of control of infection leads to enhanced but ineffective TLR4-mediated inflammatory responses that prolong disease symptoms. This indicates that TLR2 agonists may be beneficial in the treatment of early life Chlamydia infections and associated diseases