Generalized symmetric nonextensive thermostatistics and q-modified structures

We formulate a convenient generalization of the q-expectation value, based on the analogy of the symmetric quantum groups and q-calculus, and show that the q->q^{-1} symmetric nonextensive entropy preserves all of the mathematical structure of thermodynamics just as in the case of non-symmetric Tsallis statistics. Basic properties and analogies with quantum groups are discussed.Comment: 9 pages, 1 figure. To appear in Mod. Phys. Lett.

Barnett-Pegg formalism of angle operators, revivals, and flux lines

We use the Barnett-Pegg formalism of angle operators to study a rotating particle with and without a flux line. Requiring a finite dimensional version of the Wigner function to be well defined we find a natural time quantization that leads to classical maps from which the arithmetical basis of quantum revivals is seen. The flux line, that fundamentally alters the quantum statistics, forces this time quantum to be increased by a factor of a winding number and determines the homotopy class of the path. The value of the flux is restricted to the rational numbers, a feature that persists in the infinite dimensional limit.Comment: 5 pages, 0 figures, Revte

The normal ischiofemoral distance and its variations.

The aim of this study is to measure the ischiofemoral distance (IFD) in the normal hip with healthy surrounding soft tissues and describe its variations caused by gender, age and proximal femoral anatomy so that this could serve as a reference for future studies on this subject. This is a retrospective study in which we reviewed the CT scans of 149 patients (298 hips) who had a CT of their pelvis for non-orthopaedic (abdomino-pelvic) pathology. The images were reviewed by two independent observers and the IFD (the smallest distance between the lateral cortex of the ischial tuberosity and the posteromedial cortex of the lesser trochanter), offset (the perpendicular distance from the centre of the femoral head to a line running down the middle of the shaft of the femur) and the neck-shaft angle (the angle between the lines in the middle of the neck to the line forming the axis of the femoral shaft) were measured. The CT scans belonged to 71 males and 78 females (M: 48%, F: 52%), with an average age of 51  ± 19 years (range 18-92). The mean IFD was 18.6  ±  8 mm in the females and 23  ± 7 mm in the males and this difference was statistically significant (P <  0.001). The IFD increased by 1.06 mm for each 1 mm of offset and dropped by 0.09 mm with each year of age. However, the neck-shaft angle did not show any significant correlation with the IFD.This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/jhps/hnw00

Antenatal biological models in the characterisation and research of congenital lower urinary tract disorders

Congenital lower urinary tract disorders are a family of diseases affecting both urinary storage and voiding as well as upstream kidney function. Current treatments include surgical reconstruction but many children still fail to achieve urethral continence or progress to chronic kidney disease. New therapies can only be achieved through undertaking research studies to enhance our understanding of congenital lower urinary tract disorders. Animal models form a critical component of this research, a corner of the triangle composed of human in-vitro studies and clinical research. We describe the current animal models for two rare congenital bladder disorders, posterior urethral valves (PUV) and bladder exstrophy (BE). We highlight important areas for researchers to consider when deciding which animal model to use to address particular research questions and outline the strengths and weaknesses of current models available for PUV and BE. Finally, we present ideas for refining animal models for PUV and BE in the future to stimulate future researchers and help them formulate their thinking when working in this field

Work extremum principle: Structure and function of quantum heat engines

We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures $T_h > T_c$. The purpose of the engine is to extract work due to the temperature difference. Its dynamics is not restricted to the near equilibrium regime. The engine structure is determined by maximizing the extracted work under various constraints. When this maximization is carried out at finite power, the engine dynamics is described by well-defined temperatures and satisfies the local version of the second law. In addition, its efficiency is bounded from below by the Curzon-Ahlborn value $1-\sqrt{T_c/T_h}$ and from above by the Carnot value $1-(T_c/T_h)$. The latter is reached|at finite power|for a macroscopic engine, while the former is achieved in the equilibrium limit $T_h\to T_c$. When the work is maximized at a zero power, even a small (few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure

Contractile function of detrusor smooth muscle from children with posterior urethral valves – the role of fibrosis

Introduction: Posterior urethral valves (PUV) is the most common cause of congenital bladder outflow obstruction with persistent lower urinary tract and renal morbidities. There is a spectrum of functional bladder disorders ranging from hypertonia to bladder underactivity, but the aetiology of these clinical conditions remains unclear. / Aims and objectives: We tested the hypothesis that replacement of detrusor muscle with non-muscle cells and excessive deposition of connective tissue is an important factor in bladder dysfunction with PUV. We used isolated detrusor samples from children with PUV and undergoing primary or secondary procedures in comparison to age-matched data from children with functionally normal bladders. In vitro contractile properties, as well as passive stiffness, were measured and matched to histological assessment of muscle and connective tissue. We examined if a major pathway for fibrosis was altered in PUV tissue samples. / Methods: Isometric contractions were measured in vitro in response to either stimulation of motor nerves to detrusor or exposure to cholinergic and purinergic receptor agonists. Passive mechanical stiffness was measured by rapid stretching of the tissue and recording changes to muscle tension. Histology measured the relative amounts of detrusor muscle and connective tissue. Multiplex quantitative immunofluorescence labelling using five epitope markers was designed to determine cellular pathways, in particular the Wnt-signalling pathway, responsible for any changes to excessive deposition of connective tissue. / Results and Discussion: PUV tissue showed equally reduced contractile function to efferent nerve stimulation or exposure to contractile agonists. Passive muscle stiffness was increased in PUV tissue samples. The smooth muscle:connective tissue ratio was also diminished and mirrored the reduction of contractile function and the increase of passive stiffness. Immunofluorescence labelling showed in PUV samples increased expression of the matrix metalloproteinase, MMP-7; as well as cyclin-D1 expression suggesting cellular remodelling. However, elements of a fibrosis pathway associated with Wnt-signalling were either reduced (β-catenin) or unchanged (c-Myc). The accumulation of extracellular matrix, containing collagen, will contribute to the reduced contractile performance of the bladder wall. It will also increase tissue stiffness that in vivo would lead to reduced filling compliance. / Conclusions: Replacement of smooth muscle with fibrosis is a major contributory factor in contractile dysfunction in the hypertonic PUV bladder. This suggests that a potential strategy to restore normal contractile and filling properties is development of the effective use of antifibrotic agents

Low-temperature magnetization of (Ga,Mn)As semiconductors

We report on a comprehensive study of the ferromagnetic moment per Mn atom in (Ga,Mn)As ferromagnetic semiconductors. Theoretical discussion is based on microscopic calculations and on an effective model of Mn local moments antiferromagnetically coupled to valence band hole spins. The validity of the effective model over the range of doping studied is assessed by comparing with microscopic tight-binding/coherent-potential approximation calculations. Using the virtual crystal k.p model for hole states, we evaluate the zero-temperature mean-field contributions to the magnetization from the hole kinetic and exchange energies, and magnetization suppression due to quantum uctuations of Mn moment orientations around their mean-field ground state values. Experimental low-temperature ferromagnetic moments per Mn are obtained by superconducting quantum interference device and x-ray magnetic circular dichroism measurements in a series of (Ga,Mn)As semiconductors with nominal Mn doping ranging from ~2% to 8%. Hall measurements in as-grown and annealed samples are used to estimate the number of uncompensated substitutional Mn moments. Based on our comparison between experiment and theory we conclude that all these Mn moments in high quality (Ga,Mn)As materials have nearly parallel ground state alignment.Comment: 11 pages, 11 figures, submitted to Phys. Rev.

Dietary supplements in people with metastatic cancer who are experiencing malnutrition, cachexia, sarcopenia, and frailty: A scoping review

Cancer‐associated malnutrition, or cachexia, stemming from cancer or its treatments, is particularly prevalent in metastatic cancers, and is often interrelated with sarcopenia and frailty. Evidence suggests that dietary supplements play a role in managing these conditions. As metastatic cancer cells are associated with notable genomic and phenotypic alterations, response to dietary supplements may differ between metastatic and non‐metastatic cancers. However, research in this area is lacking. This scoping review aims to identify the dietary supplements that have been studied in patients with metastatic cancers and malnutrition‐related conditions, along with their proposed effects, mechanisms, outcome measures, and tools used. A systematic search was conducted across databases, including MEDLINE, EMBASE, CINAHL, and clinical trial registries. Of the initial 6535 records screened, a total of 48 studies were included, covering a range of dietary supplements— vitamins, minerals, antioxidants, proteins, amino acids, fatty acids, fiber, and others. While the types of dietary supplements included varied across cancer types, omega‐3 and carnitine were investigated most often. Proposed relevant attributes of dietary supplements included their antioxidant, anti‐inflammatory, anti‐cancer, and immunomodulatory properties. Overall, there was a paucity of interventional studies, and more randomized controlled trials are warranted