A
bstract
In this paper we return to the question of the modular properties of a generalised Gibbs ensemble of a single free fermion. We extend our previous proposals to a GGE containing an arbitrary ...number of conserved charges and provide a physical interpretation of the result in terms of a line defect. The defect description perfectly explains the product formula for the modular transformation we found previously. We also give a proposal for a Hamiltonian approach to the line defect.
A
bstract
In this paper we consider the modular properties of generalised Gibbs ensembles in the Ising model, realised as a theory of one free massless fermion. The Gibbs ensembles are given by ...adding chemical potentials to chiral charges corresponding to the KdV conserved quantities. (They can also be thought of as simple models for extended characters for the W-algebras). The eigenvalues and Gibbs ensembles for the charges can be easily calculated exactly using their expression as bilinears in the fermion fields. We re-derive the constant term in the charges, previously found by zeta-function regularisation, from modular properties. We expand the Gibbs ensembles as a power series in the chemical potentials and find the modular properties of the corresponding expectation values of polynomials of KdV charges. This leads us to an asymptotic expansion of the Gibbs ensemble calculated in the opposite channel. We obtain the same asymptotic expansion using Dijkgraaf’s results for chiral partition functions. By considering the corresponding TBA calculation, we are led to a conjecture for the exact closed-form expression of the GGE in the opposite channel. This has the form of a trace over multiple copies of the fermion Fock space. We give analytic and numerical evidence supporting our conjecture.
A
bstract
We consider a class of conformal defects in Virasoro minimal models that have been defined as fixed points of the renormalisation group and calculate the leading contribution to the ...reflection coefficient for these defects. This requires several structure constants of the operator algebra of the defect fields, for which we present a derivation in detail. We compare our results with our recent work on conformal defects in the tricritical Ising model.
WATTS T. (2012) European Journal of Cancer Care21, 20–30, End‐of‐life care pathways as tools to promote and support a good death: a critical commentary
This paper calls into question whether and how ...end‐of‐life care pathways facilitate the accomplishment of a ‘good death’. Achieving a ‘good death’ is a prominent social and political priority and an ideal which underpins the philosophy of hospice and palliative care. End‐of‐life care pathways have been devised to enhance the care of imminently dying patients and their families across care settings and thereby facilitate the accomplishment of a ‘good death’. These pathways have been enthusiastically adopted and are now recommended by governments in the UK as ‘best practice’ templates for end‐of‐life care. However, the literature reveals that the ‘good death’ is a nebulous, fluid concept. Moreover, concerns have been articulated regarding the efficacy of care pathways in terms of their impact on patient care and close analysis of two prominent end‐of‐life pathways reveals how biomedical aspects of care are privileged. Nonetheless drawing on a diverse range of evidence the literature indicates that end‐of‐life care pathways may facilitate a certain type of ‘good death’ and one which is associated with the dying process and framed within biomedicine.
Neonatal infection is an important cause of morbidity and mortality. Neonatal infection surveillance networks are necessary for defining the epidemiology of infections and monitoring changes over ...time.
Prospective multicentre surveillance using a web-based database.
12 English neonatal units.
Newborns admitted in 2006-2008, with positive blood, cerebrospinal fluid or urine culture and treated with antibiotics for at least 5 days.
Incidence, age at infection, pathogens and antibiotic resistance profiles.
With the inclusion of coagulase negative Staphylococci (CoNS), the incidence of all neonatal infection was 8/1000 live births and 71/1000 neonatal admissions (2007-2008). The majority of infections occurred in premature (<37 weeks) and low birthweight (<2500 g) infants (82% and 81%, respectively). The incidence of early onset sepsis (EOS; ≤48 h of age) was 0.9/1000 live births and 9/1000 neonatal admissions, and group B Streptococcus (58%) and Escherichia coli (18%) were the most common organisms. The incidence of late onset sepsis (LOS; >48 h of age) was 3/1000 live births and 29/1000 neonatal admissions (7/1000 live births and 61/1000 admissions including CoNS) and the most common organisms were CoNS (54%), Enterobacteriaceae (21%) and Staphylococcus aureus (18%, 11% of which were methicillin resistant S aureus). Fungi accounted for 9% of LOS (72% Candida albicans). The majority of pathogens causing EOS (95%) and LOS (84%) were susceptible to commonly used empiric first line antibiotic combinations of penicillin/gentamicin and flucloxacillin/gentamicin, respectively (excluding CoNS).
The authors have established NeonIN in England and defined the current epidemiology of neonatal infections. These data can be used for benchmarking among units, international comparisons and as a platform for interventional studies.
The induction of long-lived heterotypic T-cell protection against influenza virus remains elusive, despite the conservation of T-cell epitopes. T-cell protection against influenza is critically ...dependent on lung-resident memory T cells (Trm). Here we show that intranasal administration of 4-1BBL along with influenza nucleoprotein in a replication-defective adenovirus vector to influenza pre-immune mice induces a remarkably stable circulating effector memory CD8 T-cell population characterized by higher IL-7Rα expression than control-boosted T cells, as well as a substantial lung parenchymal CD69
CD8 Trm population, including both CD103
and CD103
cells. These T-cell responses persist to greater than 200 days post-boost and protect against lethal influenza challenge in aged (year old) mice. The expansion of the nucleoprotein-specific CD8 Trm population during boosting involves recruitment of circulating antigen-specific cells and is critically dependent on local rather than systemic administration of 4-1BBL as well as on 4-1BB on the CD8 T cells. Moreover, during primary influenza infection of mixed bone marrow chimeras, 4-1BB-deficient T cells fail to contribute to the lung-resident Trm population. These findings establish both endogenous and supraphysiological 4-1BBL as a critical regulator of lung-resident memory CD8 T cells during influenza infection.
Biological stoichiometry provides a mechanistic theory linking cellular and biochemical features of co‐evolving biota with constraints imposed by ecosystem energy and nutrient inputs. Thus, ...understanding variation in biomass carbon : nitrogen : phosphorus (C : N : P) stoichiometry is a major priority for integrative biology. Among various factors affecting organism stoichiometry, differences in C : P and N : P stoichiometry have been hypothesized to reflect organismal P‐content because of altered allocation to P‐rich ribosomal RNA at different growth rates (the growth rate hypothesis, GRH). We tested the GRH using data for microbes, insects, and crustaceans and we show here that growth, RNA content, and biomass P content are tightly coupled across species, during ontogeny, and under physiological P limitation. We also show, however, that this coupling is relaxed when P is not limiting for growth. The close relationship between P and RNA contents indicates that ribosomes themselves represent a biogeochemically significant repository of P in ecosystems and that allocation of P to ribosome generation is a central process in biological production in ecological systems.
Phenylpropanoids are the precursors to a range of important plant metabolites such as the cell wall constituent lignin and the secondary metabolites belonging to the flavonoid/stilbene class of ...compounds. The latter class of plant natural products has been shown to function in a wide range of biological activities. During the last few years an increasing number of health benefits have been associated with these compounds. In particular, they demonstrate potent antioxidant activity and the ability to selectively inhibit certain tyrosine kinases. Biosynthesis of many medicinally important plant secondary metabolites, including stilbenes, is frequently not very well understood and under tight spatial and temporal control, limiting their availability from plant sources. As an alternative, we sought to develop an approach for the biosynthesis of diverse stilbenes by engineered recombinant microbial cells.
A pathway for stilbene biosynthesis was constructed in Escherichia coli with 4-coumaroyl CoA ligase 1 4CL1) from Arabidopsis thaliana and stilbene synthase (STS) cloned from Arachis hypogaea. E. coli cultures expressing these enzymes together converted the phenylpropionic acid precursor 4-coumaric acid, added to the growth medium, to the stilbene resveratrol (>100 mg/L). Caffeic acid, added in the same way, resulted in the production of the expected dihydroxylated stilbene, piceatannol (>10 mg/L). Ferulic acid, however, was not converted to the expected stilbene product, isorhapontigenin. Substitution of 4CL1 with a homologous enzyme, 4CL4, with a preference for ferulic acid over 4-coumaric acid, had no effect on the conversion of ferulic acid. Accumulation of tri- and tetraketide lactones from ferulic acid, regardless of the CoA-ligase expressed in E. coli, suggests that STS cannot properly accommodate and fold the tetraketide intermediate to the corresponding stilbene structure.
Phenylpropionic acids, such as 4-coumaric acid and caffeic acid, can be efficiently converted to stilbene compounds by recombinant E. coli cells expressing plant biosynthetic genes. Optimization of precursor conversion and cyclization of the bulky ferulic acid precursor by host metabolic engineering and protein engineering may afford the synthesis of even more structurally diverse stilbene compounds.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper is a follow-up to J. High Energy Phys. 06, 025 (2020) in which two-dimensional conformal field theories in the presence of spin structures are studied. In the present paper we define four ...types of CFTs, distinguished by whether they need a spin structure or not in order to be well-defined, and whether their fields have parity or not. The cases of spin dependence without parity, and of parity without the need of a spin structure, have not, to our knowledge, been investigated in detail so far. We analyse these theories by extending the description of CFT correlators via three-dimensional topological field theory developed in Nucl. Phys. B 646, 353 (2002) to include parity and spin. In each of the four cases, the defining data are a special Frobenius algebra
F
F
in a suitable ribbon fusion category, such that the Nakayama automorphism of
F
F
is the identity (oriented case) or squares to the identity (spin case). We use the TFT to define correlators in terms of
F
F
and we show that these satisfy the relevant factorisation and single-valuedness conditions. We allow for world sheets with boundaries and topological line defects, and we specify the categories of boundary labels and the fusion categories of line defect labels for each of the four types. The construction can be understood in terms of topological line defects as gauging a possibly non-invertible symmetry. We analyse the case of a
\mathbb{Z}_2
ℤ
2
-symmetry in some detail and provide examples of all four types of CFT, with Bershadsky-Polyakov models illustrating the two new types.
Flavonoids are important plant-specific secondary metabolites synthesized from 4-coumaroyl coenzyme A (CoA), derived from the general phenylpropanoid pathway, and three malonyl-CoAs. The synthesis ...involves a plant type III polyketide synthase, chalcone synthase. We report the cloning and coexpression in Escherichia coli of phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coumarate:CoA ligase, and chalcone synthase from the model plant Arabidopsis thaliana. Simultaneous expression of all four genes resulted in a blockage after the first enzymatic step caused by the presence of nonfunctional cinnamate-4-hydroxylase. To overcome this problem we fed exogenous 4-coumaric acid to induced cultures. We observed high-level production of the flavanone naringenin as a result. We were also able to produce phloretin by feeding cultures with 3-(4-hydroxyphenyl)propionic acid. Feeding with ferulic or caffeic acid did not yield the corresponding flavanones. We have also cloned and partially characterized a new tyrosine ammonia lyase from Rhodobacter sphaeroides. Tyrosine ammonia lyase was substituted for phenylalanine ammonia lyase and cinnamate-4-hydroxylase in our E. coli clones and three different growth media were tested. After 48 h induction, high-level production (20.8 mg L⁻¹) of naringenin in metabolically engineered E. coli was observed for the first time.
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