Search results for "Fluidity"

Diabetes mellitus: Polymorphonuclear leukocyte (PMN) filtration parameters and PMN membrane fluidity after chemotactic activation

1999

Abstract The goal of this research was to determine leukocyte rheology at baseline and after chemotactic activation in type I and type II diabetics. In 19 normal subjects, 21 type I diabetics, and 16 type II diabetics at baseline and after in vitro chemotactic activation (prolonged for 5 and 15 minutes) with two stimulating agents (4-phorbol 12-myristate 13-acetate [PMA] and N -formyl-methionyl-leucyl-phenylalanine [fMLP]), we evaluated polymorphonuclear (PMN) filtration parameters (using a St. George filtrometer [Carri-Med, Dorking, UK] and considering the initial relative flow rate [IRFR] and the concentration of clogging particles [CP]) and PMN membrane fluidity (obtained by marking PMNs…

Thouless-Valatin Rotational Moment of Inertia from the Linear Response Theory

2017

Spontaneous breaking of continuous symmetries of a nuclear many-body system results in appearance of zero-energy restoration modes. Such modes introduce a non-physical contributions to the physical excitations called spurious Nambu-Goldstone modes. Since they represent a special case of collective motion, they are sources of important information about the Thouless-Valatin inertia. The main purpose of this work is to study the Thouless-Valatin rotational moment of inertia as extracted from the Nambu-Goldstone restoration mode that results from the zero-frequency response to the total angular momentum operator. We examine the role and effects of the pairing correlations on the rotational cha…

Unconventional phases of attractive Fermi gases in synthetic Hall ribbons

2017

An innovative way to produce quantum Hall ribbons in a cold atomic system is to use M hyperfine states of atoms in a one-dimensional optical lattice to mimic an additional "synthetic dimension." A notable aspect here is that the SU(M) symmetric interaction between atoms manifests as "infinite ranged" along the synthetic dimension. We study the many-body physics of fermions with SU(M) symmetric attractive interactions in this system using a combination of analytical field theoretic and numerical density-matrix renormalization-group methods. We uncover the rich ground-state phase diagram of the system, including unconventional phases such as squished baryon fluids, shedding light on many-body…

Fermionic superfluidity in optical lattices

2008

Membrane fatty acid composition and fluidity are involved in the resistance to freezing of Lactobacillus buchneri R1102 and Bifidobacterium longum R0…

2015

International audience; Determinations of membrane fatty acid composition and fluidity were used together with acidification activity and viability measurements to characterize the physiological state after freezing of Lactobacillus buchneri R1102 and Bifidobacterium longum R0175 cells harvested in the exponential and stationary growth phases. For both strains, lower membrane fluidity was achieved in cells harvested in the stationary growth phase. This change was linked to a lower unsaturated-to-saturated fatty acid ratio for both strains and a higher cyclic-to-saturated fatty acid ratio for L. buchneri R1102 alone. These membrane properties were linked to survival and to maintenance of aci…

Membrane fluidity, membrane lipid pattern, and cytosolic Ca2+ content in platelets from a group of type II diabetic patients with macrovascular compl…

1995

OBJECTIVE To evaluate platelet membrane fluidity and some platelet metabolic parameters in type II diabetic patients with macrovascular complications. RESEARCH DESIGN AND METHODS In a group of 21 type II diabetic patients with macrovascular complications, we evaluated platelet membrane fluidity [marking intact resting platelets with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH)], platelet membrane lipid pattern (cholesterol :phospholipid [C:PL] ratio and individual phospholipids), and platelet cytosolic Ca2+ content (marking intact resting platelets with the fluorescent probe Fura 2AM). RESULTS Platelet membrane fluidity is decreased in type II diabetic pat…

Accessing finite momentum excitations of the one-dimensional Bose-Hubbard model using superlattice modulation spectroscopy

2018

We investigate the response to superlattice modulation of a bosonic quantum gas confined to arrays of tubes emulating the one-dimensional Bose-Hubbard model. We demonstrate, using both time-dependent density matrix renormalization group and linear response theory, that such a superlattice modulation gives access to the excitation spectrum of the Bose-Hubbard model at finite momenta. Deep in the Mott-insulator, the response is characterized by a narrow energy absorption peak at a frequency approximately corresponding to the onsite interaction strength between bosons. This spectroscopic technique thus allows for an accurate measurement of the effective value of the interaction strength. On th…

Fluorescent probes to evaluate the physiological state and activity of microbial biocatalysts: A guide for prokaryotic and eukaryotic investigation

2008

International audience; Many fluorescent techniques are employed to evaluate the viability and activity of microbial cells used in biotechnology. These techniques are sometimes complex and the interpretation of results opened to misunderstanding. Moreover, new developments are constantly proposed especially concerning a more accurate evaluation of the state of the cells including eukaryotic microorganisms. This paper aims at presenting to biotechnologists unfamiliar with fluorescence the principles of these methods and the related possible pitfalls. It focuses on probes of the physical (integrity and fluidity) and energetical (intracellular pH and membrane potential) state of the cell membr…

Oxidative stress resistance in hippocampal cells is associated with altered membrane fluidity and enhanced nonamyloidogenic cleavage of endogenous am…

2010

Reactive oxygen species (ROS) have important roles as signaling molecules in the regulation of a variety of biological processes. On the other hand, chronic oxidative stress exerted by ROS is widely considered a causative factor in aging. Therefore, cells need to be able to adapt to a chronic oxidative challenge and do so to a certain cell-type-specific extent. Recently, we have shown in oxidative-stress-resistant cell lines, HT22(H2O2) and HT22(Glu), derived from the neuronal cell line HT22 by chronic exposure to sublethal concentrations of H(2)O(2) and glutamate, that, in addition to the known antioxidant defense mechanisms, e.g., activation of antioxidant enzymes or up-regulation of heat…

Oxysterols: Influence on plasma membrane rafts microdomains and development of ocular diseases

2015

Oxidation of cholesterol into oxysterols is a major way of elimination of cholesterol from the liver and extrahepatic tissues, including the brain and the retina. Oxysterols are involved in various cellular processes. Numerous links have been established between oxysterols and several disorders such as neurodegenerative pathologies, retinopathies and atherosclerosis. Different components of the lipid layer such as sphingolipids, sterols and proteins participate to membrane fluidity and forme lipid rafts microdomains. Few data are available on the links between lipids rafts and oxysterols. The purpose of this review is to suggest the potential role of lipid rafts microdomains in the developm…