On the QED Effective Action in Time Dependent Electric Backgrounds

We apply the resolvent technique to the computation of the QED effective action in time dependent electric field backgrounds. The effective action has both real and imaginary parts, and the imaginary part is related to the pair production probability in such a background. The resolvent technique has been applied previously to spatially inhomogeneous magnetic backgrounds, for which the effective action is real. We explain how dispersion relations connect these two cases, the magnetic case which is essentially perturbative in nature, and the electric case where the imaginary part is nonperturbative. Finally, we use a uniform semiclassical approximation to find an expression for very general time dependence for the background field. This expression is remarkably similar in form to Schwinger's classic result for the constant electric background.Comment: 27 pages, no figures; reference adde

Biologics and Targeted Synthetic Drugs Can Induce Immune-Mediated Glomerular Disorders in Patients with Rheumatic Diseases: An Updated Systematic Literature Review

Objective: Our objective was to update the understanding of the development of paradoxical immune-mediated glomerular disorders (IGDs) in patients with rheumatic diseases treated with biologics and targeted synthetic drugs (ts-drugs). Methods: A systematic literature review was performed by searching PubMed for articles published between 1 January 2014 and 1 January 2020 reporting on the development of IGD in adult patients with rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis or systemic lupus erythematosus (SLE) who were receiving biologics or ts-drugs. IGDs were classified on the basis of clinical, laboratory and histopathological data as (1) glomerulonephritis associated with systemic vasculitis (GNSV), (2) isolated autoimmune renal disorder (IARD) or (3) glomerulonephritis in SLE and in lupus-like syndrome (GNLS). The World Health Organization-Uppsala Monitoring Centre (WHO-UMC) system for standardized case causality assessment was applied to evaluate the causal relationship between IGD and specific drugs. The classification was based on a six-category scale, where the “certain” and “probable” categories were deemed clinically relevant relationships. Results: The literature search retrieved 875 articles. Of these, 16 articles reported IGD data, for a total of 25 cases. According to the WHO-UMC assessment, the strength of the causal relationship between IGDs and investigated drugs was higher for anti-tumor necrosis factor-α agents (a clinically relevant relationship was found in four of six cases), abatacept (one of two cases), tocilizumab (two cases), ustekinumab (one case) and tofacitinib (one case) than for rituximab (nine cases), belimumab (three cases) or secukinumab (one case), which showed a weak causal relationship with these paradoxical events. No cases associated with apremilast or baricitinib were found. The retrieved cases were classified as 11 GNLS, seven IARD and seven GNSV. Conclusions: Biologics and ts-drugs can cause IGDs. These events are rare, and the causative effect of a specific drug is hard to establish. When a patient is suspected of having an IGD, the drug should be discontinued, and treatment for the new-onset renal disorder should be promptly started

Prokaryotic Diversity of the Composting Thermophilic Phase: The Case of Ground Coffee Compost

Waste biomass coming from a local coffee company, which supplied burnt ground coffee after an incorrect roasting process, was employed as a starting material in the composting plant of the Experimental Station of the University of Naples Federico II at Castel Volturno (CE). The direct molecular characterization of compost using 13C-NMR spectra, which was acquired through cross-polarization magic-angle spinning, showed a hydrophobicity index of 2.7% and an alkyl/hydroxyalkyl index of 0.7%. Compost samples that were collected during the early “active thermophilic phase” (when the composting temperature was 63 C) were analyzed for the prokaryotic community composition and activities. Two complementary approaches, i.e., genomic and predictive metabolic analysis of the 16S rRNA V3–V4 amplicon and culture-dependent analysis, were combined to identify the main microbial factors that characterized the composting process. The whole microbial community was dominated by Firmicutes. The predictive analysis of the metabolic functionality of the community highlighted the potential degradation of peptidoglycan and the ability of metal chelation, with both functions being extremely useful for the revitalization and fertilization of agricultural soils. Finally, three biotechnologically relevant Firmicutes members, i.e., Geobacillus thermodenitrificans subsp. calidus, Aeribacillus pallidus, and Ureibacillus terrenus (strains CAF1, CAF2, and CAF5, respectively) were isolated from the “active thermophilic phase” of the coffee composting. All strains were thermophiles growing at the optimal temperature of 60 C. Our findings contribute to the current knowledge on thermophilic composting microbiology and valorize burnt ground coffee as waste material with biotechnological potentialities

Gene expression profiling of monozygotic twins affected by psoriatic arthritis

Introduction: Psoriatic Arthritis (PsA) is a multifactorial disease, where the relative burden of genetic, epigenetic and environmental factors in clinical course and damage accrual is not yet definitively clarified. In clinical practice, there is a real need for useful candidate biomarkers in PsA diagnosis and disease progression, by exploring its underlying transcrip-tomic and epigenomic mechanisms. This work aims to profile the transcriptome in mono-zygotic (MZ) twins with psoriatic arthritis (PsA) highly concordant for clinical presentation, but discordant for the radiographic outcomes’ severity. Methods: We describe i) the clinical case of two MZ twins; ii) their comparative gene expression profiling (HTA 2.0 Affymetrix) and iii) signal pathways and pathophysiological processes in which differentially expressed genes are involved (in silico analysis by the IPA software, QIAGEN). Results: One hundred sixty-three transcripts and 36 coding genes (28 up and 8 down) were differentially expressed between twins, and in the brother with the most erosive form, the transcriptomic profiling highlights the overexpression of genes known to be involved in immunomodulatory processes and on a broad spectrum of PsA manifestations. Discussion: Twins’ clinical cases are still a gold mine in medical research: twin brothers are ideal experimental models in estimating the relative importance of genetic versus nongenetic components as determinants of complex phenotypes, non-Mendelian and multifactorial diseases as PsA

Dynamical symmetry breaking in the Nambu-Jona-Lasino model with external gravitational and constant electric fields

An investigation of the Nambu-Jona-Lasino model with external constant electric and weak gravitational fields is carried out in three- and four- dimensional spacetimes. The effective potential of the composite bifermionic fields is calculated keeping terms linear in the curvature, while the electric field effect is treated exactly by means of the proper- time formalism. A rich dynamical symmetry breaking pattern, accompanied by phase transitions which are ruled, independently, by both the curvature and the electric field strength is found. Numerical simulations of the transitions are presented.Comment: 20 pages, LaTeX, 6 .ps-figures, Final version published in "Classical and Quantum Gravity

Borel Summation of the Derivative Expansion and Effective Actions

We give an explicit demonstration that the derivative expansion of the QED effective action is a divergent but Borel summable asymptotic series, for a particular inhomogeneous background magnetic field. A duality transformation B\to iE gives a non-Borel-summable perturbative series for a time dependent background electric field, and Borel dispersion relations yield the non-perturbative imaginary part of the effective action, which determines the pair production probability. Resummations of leading Borel approximations exponentiate to give perturbative corrections to the exponents in the non-perturbative pair production rates. Comparison with a WKB analysis suggests that these divergence properties are general features of derivative expansions and effective actions.Comment: 18 pp, Revtex, 2 fig

Chiral symmetry breaking in d=3 NJL model in external gravitational and magnetic fields

The phase structure of $d=3$ Nambu-Jona-Lasinio model in curved spacetime with magnetic field is investigated in the leading order of the $1/N$-expansion and in linear curvature approximation (an external magnetic field is treated exactly). The possibility of the chiral symmetry breaking under the combined action of the external gravitational and magnetic fields is shown explicitly. At some circumstances the chiral symmetry may be restored due to the compensation of the magnetic field by the gravitational field.Comment: 7 pages, LaTe

Exact Primordial Black Strings in Four Dimensions

A solution of effective string theory in four dimensions is presented which admits interpretation of a rotating black cosmic string. It is constructed by tensoring the three dimensional black hole, extended with the Kalb-Ramond axion, with a flat direction. The physical interpretation of the solution is discussed, with special attention on the axion, which is found to play a role very similar to a Higgs field. Finally, it is pointed out that the solution represents an exact WZWN $\sigma$ model on the string world sheet, to all orders in the inverse string tension $\alpha'$.Comment: 11 pages plain TeX, Univ. of Alberta preprint Alberta-THY-14-199

Exact solutions of Einstein and Einstein-scalar equations in 2 + 1 dimensions

A nonstatic and circularly symmetric exact solution of the Einstein equations (with a cosmological constant $\Lambda$ and null fluid) in $2+1$ dimensions is given. This is a nonstatic generalization of the uncharged spinless BTZ metric. For $\Lambda = 0$, the spacetime is though not flat, the Kretschmann invariant vanishes. The energy, momentum, and power output for this metric are obtained. Further a static and circularly symmetric exact solution of the Einstein-massless scalar equations is given, which has a curvature singularity at $r =0$ and the scalar field diverges at $r=0$ as well as at infinity .Comment: 8 pages, Latex, no numbe