Dairy products can be manufactured in a variety of structural forms (e.g., liquid, semi-solids, and solids). Although liquid milk is a colloidal dispersion of fat and protein in the serum portion, it ...can easily be converted into a soft gel (yogurt) upon acid coagulation. Similarly, cheese, a rennet-coagulated, casein-rich fraction of milk, falls in the category of semi-solid foods. Structurally, all of these materials are complex in nature because of interactions between protein, fat, and water components. The structural origin of these diversified food textures is derived from the way that various food constituents are arranged to form a unique body or mass. Food materials science helps in the assessment of structural arrangements of these molecules at various length scales. This article focuses on the use of various materials science approaches for understanding the fundamental relationship between process, structure, and property in solving critical issues that pertain to the dairy industry and academia.
ABSTRACT Using high-resolution 3D and 2D (axisymmetric) hydrodynamic simulations in spherical geometry, we study the evolution of cool cluster cores heated by feedback-driven bipolar active galactic ...nuclei (AGNs) jets. Condensation of cold gas, and the consequent enhanced accretion, is required for AGN feedback to balance radiative cooling with reasonable efficiencies, and to match the observed cool core properties. A feedback efficiency (mechanical luminosity where is the mass accretion rate at 1 kpc) as small as 6 × 10−5 is sufficient to reduce the cooling/accretion rate by ∼10 compared to a pure cooling flow in clusters (with ). This value is much smaller compared to the ones considered earlier, and is consistent with the jet efficiency and the fact that only a small fraction of gas at 1 kpc is accreted onto the supermassive black hole (SMBH). The feedback efficiency in earlier works was so high that the cluster core reached equilibrium in a hot state without much precipitation, unlike what is observed in cool-core clusters. We find hysteresis cycles in all our simulations with cold mode feedback: condensation of cold gas when the ratio of the cooling-time to the free-fall time ( ) is 10 leads to a sudden enhancement in the accretion rate; a large accretion rate causes strong jets and overheating of the hot intracluster medium such that further condensation of cold gas is suppressed and the accretion rate falls, leading to slow cooling of the core and condensation of cold gas, restarting the cycle. Therefore, there is a spread in core properties, such as the jet power, accretion rate, for the same value of core entropy or . A smaller number of cycles is observed for higher efficiencies and for lower mass halos because the core is overheated to a longer cooling time. The 3D simulations show the formation of a few-kpc scale, rotationally supported, massive ( ) cold gas torus. Since the torus gas is not accreted onto the SMBH, it is largely decoupled from the feedback cycle. The radially dominant cold gas (T < 5 × 104 K; ) consists of fast cold gas uplifted by AGN jets and freely infalling cold gas condensing out of the core. The radially dominant cold gas extends out to 25 kpc for the fiducial run (halo mass and feedback efficiency 6 × 10−5), with the average mass inflow rate dominating the outflow rate by a factor of 2. We compare our simulation results with recent observations.
These recommendations provide an evidence-based approach to the role of esophageal stents in the management of benign and malignant diseases. These guidelines have been developed under the auspices ...of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. The following guidelines are based on a critical review of the available scientific literature on the topic identified in Medline and PubMed (January 1992-December 2008) using search terms that included stents, self-expandable metal stents, self-expandable plastic stents, esophageal cancer, esophageal adenocarcinoma, esophageal squamous cell carcinoma, esophageal stricture, perforations, anastomotic leaks, tracheoesophageal fistula, and achalasia. These guidelines are intended for use by health-care providers and apply to adult, but not pediatric, patients. As with other practice guidelines, these guidelines are not intended to replace clinical judgment but rather to provide general guidelines applicable to the majority of patients. Clinicians need to integrate recommendations with their own clinical judgment, and with individual patient circumstances, values, and preferences. They are intended to be flexible, in contrast to standards of care, which are inflexible policies designed to be followed in every case. Specific recommendations are based on relevant published information. The quality of evidence and strength of recommendations have been assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system, which is a system that has been adopted by multiple national and international societies. The GRADE system is based on a sequential assessment of quality of evidence, followed by assessment of the balance between benefits vs. downsides (harms, burden, and costs) and subsequent judgment regarding the strength of recommendation.
•Provides evolution of indices measure development and sustainable development.•Describe key characteristics of a good Index.•Discusses frameworks used in developing Sustainable Development Indices ...(SDIs)•Discusses the steps in construction of Composite SDI based on aggregated framework.•Approaches and levels of application of the SDIs used across globe.
Sustainable development is a multi-dimensional concept, which emphasizes integration and striking a dynamic balance between economic, social and environmental aspects in a region, to ensure inter-generational and intra-generational equity. One of the major tools to address sustainability concerns is to have indices, which can measure the performance of a region on various dimensions of sustainable development. The review suggests there are various indices that are available at the global scale that compare different countries on different aspects of sustainability; however, a limited number of studies have been reported at regional scale. Further, the paper appraises about the various approaches and frameworks used to develop these Sustainable Development Indices (SDIs). The merits and demerits of these approaches and frameworks have been discussed. The review finds that top-down approaches have been generally employed for construction of SDIs. However, bottom-up approaches which are rarely used, also need to be developed in order to construct robust, contextual and consensus based SDIs. The review shows that composite SDIs are the most common form of framework used across the globe. Most studies have been found to use 30–60 indicators for development of SDIs. The key steps to be followed for construction of Composite Sustainable Development Indices (CSDIs) have been reviewed in detail. The review finds variable processes and steps followed by different studies for development of SDIs. Based on the review, research gaps have been identified and recommendations on steps to be followed in construction of new CSDI have been provided. The review also reveals that most studies have focused on assessment of current state of sustainable development, a limited number where the trends have been studies; no study related to the future projections/predictions of the SDI has been reported in the literature.
ABSTRACT
We use the high-resolution TNG50 cosmological magnetohydrodynamical simulation to explore the properties and origin of cold circumgalactic medium (CGM) gas around massive galaxies (M⋆ > 1011 ...M⊙ ) at intermediate redshift ($z \sim 0.5$). We discover a significant abundance of small-scale, cold gas structure in the CGM of ‘red and dead’ elliptical systems, as traced by neutral H i and Mg ii. Halos can host tens of thousands of discrete absorbing cloudlets, with sizes of order a kpc or smaller. With a Lagrangian tracer analysis, we show that cold clouds form due to strong $\delta \rho / \bar{\rho } \gg 1$ gas density perturbations that stimulate thermal instability. These local overdensities trigger rapid cooling from the hot virialized background medium at ∼107 K to radiatively inefficient ∼104 K clouds, which act as cosmologically long-lived, ‘stimulated cooling’ seeds in a regime where the global halo does not satisfy the classic tcool/tff < 10 criterion. Furthermore, these small clouds are dominated by magnetic rather than thermal pressure, with plasma β ≪ 1, suggesting that magnetic fields may play an important role. The number and total mass of cold clouds both increase with resolution, and the mgas ≃ 8 × 104 M⊙ cell mass of TNG50 enables the ∼ few hundred pc, small-scale CGM structure we observe to form. Finally, we make a preliminary comparison against observations from the COS-LRG, LRG-RDR, COS-Halos, and SDSS LRG surveys. We broadly find that our recent, high-resolution cosmological simulations produce sufficiently high covering fractions of extended, cold gas as observed to surround massive galaxies.
A dietary source of antibiotic tolerance Lundgren, Patrick; Sharma, Prateek V.; Thaiss, Christoph A.
Cell metabolism,
08/2021, Letnik:
33, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Antibiotic tolerance enables microorganisms to survive the exposure to antibiotics and serves as a precursor to antibiotic resistance. In a recent issue of Nature Microbiology, Liu et al. (2021) ...describe that high-fat-diet-induced changes in the intestinal microbiome and metabolome facilitate the development of antibiotic tolerance by bacterial pathogens.
Antibiotic tolerance enables microorganisms to survive the exposure to antibiotics and serves as a precursor to antibiotic resistance. In a recent issue of Nature Microbiology, Liu et al. describe that high-fat-diet-induced changes in the intestinal microbiome and metabolome facilitate the development of antibiotic tolerance by bacterial pathogens.
...miss rate by a human endoscopist has been strictly associated with one or more of these factors.1 As only one every two lesions was rated as adenomatous by centralised pathology in the original ...study3 (see online supplementary data), AI may result in the useless removal of hyperplastic polyps. ...a leave in situ strategy at least for distal non-adenomatous lesions is critical for AI not to increase false-positive rate at colonoscopy. Despite the general enthusiasm, prospective series are affected by ineludible operator-related bias, as the endoscopist cannot be blinded in most of the cases to the innovative technique. ...retrospective reassessment of whole colonoscopy videos, such as those in our series, owns the unique advantage of eliminating all of these subjective biases, objectively exposing independent videos to the new technologies. ...a possible bias that we could not eliminate is the fact that AI had in each video clip a relatively long interval between a few seconds before polyp appearance and the use of snare or another device. ...we could not exclude in principle that AI was somewhat facilitated by the fact that the polyp is usually put in a better and close position to the endoscope before resection. ...AI cannot compensate for lesions missed for a suboptimal exploration of colorectal mucosa. ...an adequate level of cleansing, a longer than 6 min withdrawal time and a good withdrawal technique remain prerequisites to maximise the performance of AI.6 We limited our study to white-light high definition colonoscopy.
We study the interplay among cooling, heating, conduction and magnetic fields in gravitationally stratified plasmas using simplified, plane-parallel numerical simulations. Since the physical heating ...mechanism remains uncertain in massive haloes such as groups or clusters, we adopt a simple, phenomenological prescription which enforces global thermal equilibrium and prevents a cooling flow. The plasma remains susceptible to local thermal instability, however, and cooling drives an inward flow of material. For physically plausible heating mechanisms in clusters, the thermal stability of the plasma is independent of its convective stability. We find that the ratio of the cooling time-scale to the dynamical time-scale t
cool/t
ff controls the non-linear evolution and saturation of the thermal instability: when t
cool/t
ff≲ 1, the plasma develops extended multiphase structure, whereas when t
cool/t
ff≳ 1 it does not. (In a companion paper, we show that the criterion for thermal instability in a more realistic, spherical potential is somewhat less stringent, t
cool/t
ff≲ 10.) When thermal conduction is anisotropic with respect to the magnetic field, the criterion for multiphase gas is essentially independent of the thermal conductivity of the plasma. Our criterion for local thermal instability to produce multiphase structure is an extension of the cold versus hot accretion modes in galaxy formation that applies at all radii in hot haloes, not just to the virial shock. We show that this criterion is consistent with data on multiphase gas in galaxy groups and clusters; in addition, when t
cool/t
ff≳ 1, the net cooling rate to low temperatures and the mass flux to small radii are suppressed enough relative to models without heating to be qualitatively consistent with star formation rates and X-ray line emission in groups and clusters.
We present global multidimensional numerical simulations of the plasma that pervades the dark matter haloes of clusters, groups and massive galaxies (the 'intracluster medium'; ICM). Observations of ...clusters and groups imply that such haloes are roughly in global thermal equilibrium, with heating balancing cooling when averaged over sufficiently long time- and length-scales; the ICM is, however, very likely to be locally thermally unstable. Using simple observationally motivated heating prescriptions, we show that local thermal instability (TI) can produce a multiphase medium - with ∼ 104 K cold filaments condensing out of the hot ICM - only when the ratio of the TI time-scale in the hot plasma (t
TI) to the free-fall time-scale (t
ff) satisfies t
TI/t
ff≲ 10. This criterion quantitatively explains why cold gas and star formation are preferentially observed in low-entropy clusters and groups. In addition, the interplay among heating, cooling and TI reduces the net cooling rate and the mass accretion rate at small radii by factors of ∼ 100 relative to cooling-flow models. This dramatic reduction is in line with observations. The feedback efficiency required to prevent a cooling flow is ∼ 10−3 for clusters and decreases for lower mass haloes; supernova heating may be energetically sufficient to balance cooling in galactic haloes. We further argue that the ICM self-adjusts so that t
TI/t
ff≳ 10 at all radii. When this criterion is not satisfied, cold filaments condense out of the hot phase and reduce the density of the ICM. These cold filaments can power the black hole and/or stellar feedback required for global thermal balance, which drives t
TI/t
ff≳ 10. In comparison to clusters, groups have central cores with lower densities and larger radii. This can account for the deviations from self-similarity in the X-ray luminosity-temperature (
) relation. The high-velocity clouds observed in the Galactic halo can be due to local TI producing multiphase gas close to the virial radius if the density of the hot plasma in the Galactic halo is >rsim 10−5 cm−3 at large radii.
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