Reversible gelation and dynamical arrest of dipolar colloids

We use molecular dynamics simulations of a simple model to show that dispersions of slightly elongated colloidal particles with long-range dipolar interactions, like ferrofluids, can form a physical (reversible) gel at low volume fractions. On cooling, the particles first self-assemble into a transient percolating network of cross-linked chains, which, at much lower temperatures, then undergoes a kinetic transition to a dynamically arrested state with broken ergodicity. This transition from a transient to a frozen gel is characterised by dynamical signatures reminiscent of jamming in much denser dispersions.Comment: 6 pages, 7 figure

Continuous phase transition in polydisperse hard-sphere mixture

In a previous paper (J. Zhang {\it et al.}, J. Chem. Phys. {\bf 110}, 5318 (1999)) we introduced a model for polydisperse hard sphere mixtures that is able to adjust its particle-size distribution. Here we give the explanation of the questions that arose in the previous description and present a consistent theory of the phase transition in this system, based on the Percus-Yevick equation of state. The transition is continuous, and like Bose-Einstein condensation a macroscopic aggregate is formed due to the microscopic interactions. A BMCSL-like treatment leads to the same conclusion with slightly more accurate predictions.Comment: 7 pages including 5 figures in revte

Dielectric response of a polar fluid trapped in a spherical nanocavity

We present extensive Molecular Dynamics simulation results for the structure, static and dynamical response of a droplet of 1000 soft spheres carrying extended dipoles and confined to spherical cavities of radii $R=2.5$, 3, and 4 nm embedded in a dielectric continuum of permittivity $\epsilon' \geq 1$. The polarisation of the external medium by the charge distribution inside the cavity is accounted for by appropriate image charges. We focus on the influence of the external permittivity $\epsilon'$ on the static and dynamic properties of the confined fluid. The density profile and local orientational order parameter of the dipoles turn out to be remarkably insensitive to $\epsilon'$. Permittivity profiles $\epsilon(r)$ inside the spherical cavity are calculated from a generalised Kirkwood formula. These profiles oscillate in phase with the density profiles and go to a ``bulk'' value $\epsilon_b$ away from the confining surface; $\epsilon_b$ is only weakly dependent on $\epsilon'$, except for $\epsilon' = 1$ (vacuum), and is strongly reduced compared to the permittivity of a uniform (bulk) fluid under comparable thermodynamic conditions. The dynamic relaxation of the total dipole moment of the sample is found to be strongly dependent on $\epsilon'$, and to exhibit oscillatory behaviour when $\epsilon'=1$; the relaxation is an order of magnitude faster than in the bulk. The complex frequency-dependent permittivity $\epsilon(\omega)$ is sensitive to $\epsilon'$ at low frequencies, and the zero frequency limit $\epsilon(\omega=0)$ is systematically lower than the ``bulk'' value $\epsilon_b$ of the static primitivity.Comment: 12 pages including 17 figure

What do emulsification failure and Bose-Einstein condensation have in common?

Ideal bosons and classical ring polymers formed via self-assembly, are known to have the same partition function, and so analogous phase transitions. In ring polymers, the analogue of Bose-Einstein condensation occurs when a ring polymer of macroscopic size appears. We show that a transition of the same general form occurs within a whole class of systems with self-assembly, and illustrate it with the emulsification failure of a microemulsion phase of water, oil and surfactant. As with Bose-Einstein condensation, the transition occurs even in the absence of interactions.Comment: 7 pages, 1 figure, typeset with EUROTeX, uses epsfi

The association of changes in body mass index and metabolic parameters between adults with overweight or obesity and their children in a family-based randomized trial (DiOGenes)

Background: Family-based approaches have been reported to be effective in improving overweight or obesity in children. Objectives: To investigate the relationship of changes in body mass index and metabolic parameters between adults with overweight or obesity and their children during a weight-maintenance family-based dietary intervention. Methods: In a multicentre randomized controlled trial, families with at least one parent with overweight or obesity and one healthy child aged between 5 and 18 years, of which the parents completed an 8-week weight-loss phase successfully, were randomized into five different dietary intervention groups to achieve weight maintenance for 6 months. Anthropometric parameters and body composition were measured and blood samples were collected before and after the dietary intervention. Data were analysed using Pearson correlation coefficient analyses and multiple linear regression analysis adjusted for diet group, centre, child's sex and age. Results: A positive association was found between the change in body mass index (BMI) of the mother and change in BMI-for-age Z-score of first and second child (std (Formula presented.) = 0.248, p = 0.000; std (Formula presented.) = 0.326, p = 0.000, respectively). The change in BMI of the father was only significantly associated with the change in BMI-for-age Z-score of first child (std (Formula presented.) = 0.186, p = 0.031). No consistent pattern of associations between parents and children was found for homeostatic model assessment for insulin resistance, fasting glucose and fasting insulin. Conclusion: This study supports the inclusion of parents into family-based dietary approaches for weight management of their children regardless of the child's weight status in eight different countries throughout Europe. © 2021 The Authors. Pediatric Obesity published by John Wiley & Sons Ltd on behalf of World Obesity Federation

The renewable energy and energy efficiency potential of Waitakere City : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Technology in Energy Management at Massey University

Electricity restrictions and blackouts have occurred in Waitakere City in the past and are likely to occur again in the future unless the city can become more self reliant by meeting, at least in part, the increasing energy requirements for what is one of the fastest growing cities in New Zealand. In this study the potentials for energy conservation, energy efficiency and renewable energy resources have been broadly quantified and assessed using desktop analysis of publicly available data for stationary final use energy systems (i.e. excluding transportation) within the geographical area of Waitakere City and adjoining waters. It was found that energy efficiency and energy conservation measures can consistently and predictably achieve overall energy savings and reduce daily and seasonal peak demand. The best renewable energy resource potential exists with solar and geothermal for heating applications and wave, offshore and inshore wind and tidal currents for electricity generation. There is very limited potential for hydro and bioenergy systems beyond what already exists. PV solar and land based wind power generation are currently only feasible for limited off-grid applications. This scoping study confirms the achievability of the vision expressed in Waitakere City Council's "Long Term Council Community Plan" (LTCCP) that by 2020 " Waitakere City will be an energy cell, not an energy sink. Air quality supports good health". A range of flagship projects have been identified to progress the achievement of this vision. Waitakere City Council can use this report as part of the development of a comprehensive energy management plan

О синергетическом феномене наноструктурного композита краситель–цеолит

Рассмотрены причины возникновения аномального эффекта люминесценции при создании нанокомпозита краситель–цеолитРозглянуто причини виникнення аномального ефекту люмінесценції при створенні нанокомпозиту барвник–цеоліт.The causes of the origin of an abnormal effect of luminescence at creating dye–zeolite nanocomposite are considered

Increased Postprandial Nonesterified Fatty Acid Appearance and Oxidation in Type 2 Diabetes Is Not Fully Established in Offspring of Diabetic Subjects

BACKGROUND: It has been proposed that abnormal postprandial plasma nonesterified fatty acid (NEFA) metabolism may participate in the development of tissue lipotoxicity and type 2 diabetes (T2D). We previously found that non-diabetic offspring of two parents with T2D display increased plasma NEFA appearance and oxidation rates during intravenous administration of a fat emulsion. However, it is currently unknown whether plasma NEFA appearance and oxidation are abnormal during the postprandial state in these subjects at high-risk of developing T2D. METHODOLOGY: Palmitate appearance and oxidation rates and glycerol appearance rate were determined in eleven healthy offspring of two parents with T2D (positive family history, FH+), 13 healthy subjects without first-degree relatives with T2D (FH-) and 12 subjects with T2D at fasting, during normoglycemic hyperinsulinemic clamp and during continuous oral intake of a standard liquid meal to achieve steady postprandial NEFA and triacylglycerols (TG) without and with insulin infusion to maintain similar glycemia in all three groups. PRINCIPAL FINDINGS: Plasma palmitate appearance and oxidation were higher at fasting and during the clamp conditions in the T2D group (all P<0.05). In the postprandial state, palmitate appearance, oxidative and non oxidative rates were all elevated in T2D (all P<0.05) but not in FH+. Both T2D and FH+ displayed elevated postprandial TG vs. FH- (P<0.001). Acute correction of hyperglycemia during the postprandial state did not affect these group differences. Increased waist circumference and BMI were positively associated with elevated postprandial plasma palmitate appearance and oxidation. CONCLUSIONS/SIGNIFICANCE: Postprandial plasma NEFA intolerance observed in subjects with T2D is not fully established in non-diabetic offspring of both parents with T2D, despite the presence of increased postprandial plasma TG in the later. Elevated postprandial plasma NEFA appearance and oxidation in T2D is observed despite acute correction of the exaggerated glycemic excursion in this group

Некоторые патофизиологические аспекты хирургического лечения гнойно−деструктивных поражений кишечника

Проанализированы принципы хирургического лечения больных с гнойно−деструктивными поражениями кишечника. Сделан вывод, что обязательным элементом такого лечения при любом варианте заболевания является полное и стабильное восстановление кишечного пассажа, причем сроки восстановления должны быть опережающими в отношении нарастающих расстройств гомеостаза и дегенеративных нарушений в выключенных отделах кишечного тракта.The author analyzes the principles of treatment of patients with purulent destructive lesions of the intestine. It is concluded that the obligatory element of this treatment in any type of the disease is complete and stable restoration of the intestine passage. The terms of restoration should forestall the increasing homeostasis disorders and degenerative changes in the excluded portions of the intestinal tract