355 research outputs found
Microscopy with undetected photons in the mid-infrared
Owing to its capacity for unique (bio)-chemical specificity, microscopy
withmid-IR illumination holds tremendous promise for a wide range of biomedical
and industrial applications. The primary limitation, however, remains
detection; with current mid-IR detection technology often marrying inferior
technical capabilities with prohibitive costs. This has lead to approaches that
shift detection towavelengths into the visible regime, where vastly superior
silicon-based cameratechnology is available. Here, we experimentally show how
nonlinear interferometry with entangled light can provide a powerful tool for
mid-IR microscopy, while only requiring near-infrared detection with a standard
CMOS camera. In this proof-of-principle implementation, we demonstrate
intensity imaging overa broad wavelength range covering 3.4-4.3um and
demonstrate a spatial resolution of 35um for images containing 650 resolved
elements. Moreover, we demonstrate our technique is fit for purpose, acquiring
microscopic images of biological tissue samples in the mid-IR. These results
open a new perspective for potential relevance of quantum imaging techniques in
the life sciences.Comment: back-to-back submission with arXiv:2002.05956, Anna V. Paterova,
Sivakumar M. Maniam, Hongzhi Yang, Gianluca Grenci, and Leonid A. Krivitsky,
"Hyperspectral Infrared Microscopy With Visible Light
Charged black holes: Wave equations for gravitational and electromagnetic perturbations
A pair of wave equations for the electromagnetic and gravitational
perturbations of the charged Kerr black hole are derived. The perturbed
Einstein-Maxwell equations in a new gauge are employed in the derivation. The
wave equations refer to the perturbed Maxwell spinor and to the shear
of a principal null direction of the Weyl curvature. The whole
construction rests on the tripod of three distinct derivatives of the first
curvature of a principal null direction.Comment: 12 pages, to appear in Ap.
Structural deformations analysis by means of Kalman-filtering
The surveillance of engineering structures like dams is an interdisciplinary task and mainly focused on the assessment of stability and reliability of the objects to be monitored. To show the co-operation of the disciplines involved in a comprehensible manner, it is suitable to use system analysis approaches. Structural deformations analysis by means of system analysis is explained in the following with an example of a dam. The determination of the dam deformations is demonstrated by an integration of computed and measured data by using Kalman Filtering
In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses
This study challenged to produce phosphate-based glasses (PBG) for the treatment of osseous defects. The glasses contained, among other components, 40 mol% CaO and 1-5 mol% TiO(2). The mechanical performance and in vitro biocompatibility using both human osteosarcoma and primary osteoblasts were carried out. Incorporation of TiO(2) into PBG had no significant effect on strength and modulus. These glasses encouraged attachment and maintained high viability of osteosarcoma cells similar to the positive control surface. Cells grown directly (on glasses) or indirectly (in the presence of glass extracts) showed similar proliferation pattern to the positive control cells with no significant effect of TiO(2) detected. Increasing TiO(2) content, however, has a profound effect on cytoskeleton organization and spreading and maturation of primary osteoblasts. It is believed that TiO(2) might have acted as a chemical cue-modulating cells response, and hence the substrates supported maturation/mineralization of the primary osteoblasts
Quantum Dot Nanomedicine Formulations Dramatically Improve Pharmacological Properties and Alter Uptake Pathways of Metformin and Nicotinamide Mononucleotide in Aging Mice
Orally administered Ag2S quantum dots (QDs) rapidly cross the small intestine and are taken up by the liver. Metformin and nicotinamide mononucleotide (NMN) target metabolic and aging processes within the liver. This study examined the pharmacology and toxicology of QD-based nanomedicines as carriers of metformin and NMN in young and old mice, determining if their therapeutic potency and reduced effects associated with aging could be improved. Pharmacokinetic studies demonstrated that QD-conjugated metformin and NMN have greater bioavailability, with selective accumulation in the liver following oral administration compared to unconjugated formulations. Pharmacodynamic data showed that the QD-conjugated medicines had increased physiological, metabolic, and cellular potency compared to unconjugated formulations (25× metformin; 100× NMN) and highlighted a shift in the peak induction of, and greater metabolic response to, glucose tolerance testing. Two weeks of treatment with low-dose QD-NMN (0.8 mg/kg/day) improved glucose tolerance tests in young (3 months) mice, whereas old (18 and 24 months) mice demonstrated improved fasting and fed insulin levels and insulin resistance. High-dose unconjugated NMN (80 mg/kg/day) demonstrated improvements in young mice but not in old mice. After 100 days of QD (320 μg/kg/day) treatment, there was no evidence of cellular necrosis, fibrosis, inflammation, or accumulation. Ag2S QD nanomedicines improved the pharmacokinetic and pharmacodynamic properties of metformin and NMN by increasing their therapeutic potency, bypassing classical cellular uptake pathways, and demonstrated efficacy when drug alone was ineffective in aging mice
Metabolic control level and glucose variability in adolescents with type 1 diabetes during low and high-intensity exercise
OBJECTIVE
The main purpose of this study was to characterize the determinants of metabolic changes in young type 1 diabetes (T1DM) and to determine glycemic variability during low and high-intensity exercise.
PATIENTS AND METHODS
20 young male T1DM patients were divided into two subgroups characterized by levels of glycated hemoglobin (HbA1c): HbA1c7.3% (worse HbA1c subgroup, n=10). All participants performed a maximal oxygen uptake test and two efforts of various intensities (45 minutes of aerobic exercise and 30 minutes of mixed aerobic-anaerobic intensity exercise). Continuous glucose monitors (CGM) were used to control the glucose concentration.
RESULTS
Changes in biomarkers describing the metabolic response were similar in both groups. A comparison of applied efforts exhibited that maximal capacity effort resulted in the highest values of blood glucose (BG) at the end (150.9-160.6 mg/dl) and 1 hour after the exercise (140.2-161.3 mg/dl). BG concentration before, during, 1 hour, and 24 hours after each exercise was insignificantly higher in the worse Hb1Ac group.
CONCLUSIONS
HbA1c levels are insufficient to confirm whether the applied effort is performed in acceptable glycemic values. The CGM monitors allow for precise control of BG variations and accurate planning of physical activity by adjusting the insulin and carbohydrate consumption dose
The protein corona determines the cytotoxicity of nanodiamonds: implications of corona formation and its remodelling on nanodiamond applications in biomedical imaging and drug delivery
The use of nanodiamonds for biomedical and consumer applications is growing rapidly. As their use
becomes more widespread, so too do concerns around their cytotoxicity. The cytotoxicity of
nanodiamonds correlates with their cellular internalisation and circulation time in the body. Both
internalisation and circulation time are influenced by the formation of a protein corona on the
nanodiamond surface. However, a precise understanding of both how the corona forms and evolves and
its influence on cytotoxicity is lacking. Here, we investigated protein corona formation and evolution in
response to two classes of nanodiamonds, pristine and aminated, and two types of proteins, bovine
serum albumin and fibronectin. Specifically, we found that a corona made of bovine serum albumin
(BSA), which represents the most abundant protein in blood plasma, reduced nanodiamond
agglomeration. Fibronectin (FN9-10), the second most abundant protein found in the plasma, exhibited
a significantly higher nanodiamond binding affinity than BSA, irrespective of the nanodiamond surface
charge. Finally, nanodiamonds with a BSA corona displayed less cytotoxicity towards nonphagocytic liver
cells. However, regardless of the type of corona (FN9-10 or BSA), both classes of nanodiamonds induced
substantial phagocytic cell death. Our results emphasise that a precise understanding of the corona
composition is fundamental to determining the fate of nanoparticles in the body
Kerr-AdS and its Near-horizon Geometry: Perturbations and the Kerr/CFT Correspondence
We investigate linear perturbations of spin-s fields in the Kerr-AdS black
hole and in its near-horizon geometry (NHEK-AdS), using the Teukolsky master
equation and the Hertz potential. In the NHEK-AdS geometry we solve the
associated angular equation numerically and the radial equation exactly. Having
these explicit solutions at hand, we search for linear mode instabilities. We
do not find any (non-)axisymmetric instabilities with outgoing boundary
conditions. This is in agreement with a recent conjecture relating the
linearized stability properties of the full geometry with those of its
near-horizon geometry. Moreover, we find that the asymptotic behaviour of the
metric perturbations in NHEK-AdS violates the fall-off conditions imposed in
the formulation of the Kerr/CFT correspondence (the only exception being the
axisymmetric sector of perturbations).Comment: 26 pages. 4 figures. v2: references added. matches published versio
One-loop Quantum Gravity in Schwarzschild Spacetime
The quantum theory of linearized perturbations of the gravitational field of
a Schwarzschild black hole is presented. The fundamental operators are seen to
be the perturbed Weyl scalars and associated with the
Newman-Penrose description of the classical theory. Formulae are obtained for
the expectation values of the modulus squared of these operators in the
Boulware, Unruh and Hartle-Hawking quantum states. Differences between the
renormalized expectation values of both and
in the three quantum states are evaluated
numerically.Comment: 39 pages, 11 Postscript figures, using revte
Biological impact of nanodiamond particles – label free, high-resolution methods for nanotoxicity assessment
Current methods for the assessment of nanoparticle safety that are based on 2D cell culture models and fluorescence-based assays show limited sensitivity and they lack biomimicry. Consequently, the health risks associated with the use of many nanoparticles have not yet been established. There is a need to develop in vitro models that mimic physiology more accurately and enable high throughput assessment. There is also a need to set up new assays that offer high sensitivity and are label-free. Here we developed ‘mini-liver’ models using scaffold-free bioprinting and used these models together with label-free nanoscale techniques for the assessment of toxicity of nanodiamond produced by laser-assisted technology. Results showed that NDs induced cytotoxicity in a concentration and exposure-time dependent manner. The loss of cell function was confirmed by increased cell stiffness, decreased cell membrane barrier integrity and reduced cells mobility. We further showed that NDs elevated the production of reactive oxygen species and reduced cell viability. Our approach that combined mini-liver models with label-free high-resolution techniques showed improved sensitivity in toxicity assessment. Notably, this approach allowed for label-free semi-high throughput measurements of nanoparticle-cell interactions, thus could be considered as a complementary approach to currently used methods
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