Carbon dots are a subset of carbon nanomaterials with fluorescent properties that render them attractive for various potential applications such as bioimaging and sensing. The past years saw significant progress being made in the understanding of the formation and the underlying fluorescent property. Nevertheless, efforts are still necessary to unravel the formation of carbon dots and the origin of their luminescence, especially for new types of precursor material such as polycyclic aromatic compounds.
View Article and Find Full Text PDFSurfactants aggregate in water into micelles, and these micelles incorporate organic substances to solubilize them. Hydrotropes are compounds that increase the solubility of hydrophobic substances in water without this form of aggregation. Decreasing the chain length of the classical surfactant Aerosol OT (AOT) from C8 to C5 results in a molecule with intermediate properties.
View Article and Find Full Text PDFThorite, (ThSiO4) with a zircon type structure, is one of the most abundant natural sources of thorium on Earth. Generally, actinides are known to form nanoparticles in silicate medium, though no direct link between those colloids and the crystalline form of thorite was evidenced until now. Here we show the formation of thorite from colloids and nanocrystalline structures under experimental conditions close to environmental pH and temperature.
View Article and Find Full Text PDFPoly(diallyldimethylammonium chloride) (PDDA) capped copper hexacyanoferrate nanoparticles (CuHCF NPs) with the controlled size are prepared following a precipitation method. While PDDA and CuHCF are not active at the cyclohexane/water interface, PDDA capped CuHCF NPs present synergistic property permitting them to stabilise oil-in-water emulsions for weeks. These latter can be considered as promising precursors for the development of new porous materials considering the fact that the NPs present some interests in the field of nuclear decontamination.
View Article and Find Full Text PDFUV spectrophotometry is largely used for water and wastewater quality monitoring. The measurement/estimation of specific and aggregate parameters such as nitrate and dissolved organic carbon (DOC) is possible with UV spectra exploitation, from 2 to multi wavelengths calibration. However, if nitrate determination from UV absorbance is known, major optical interferences linked to the presence of suspended solids, colloids or dissolved organic matter limit the relevance of UV measurement for DOC assessment.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2016
Prussian blue analogs (PBAs) are materials well known for their bulk physical and (electro)-chemical properties, with an outstanding selectivity for caesium in ion exchange processes. Crystalline nano-tiles, made of copper based PBA, are produced and dispersed in water by tuning their electrostatic interactions. The shape and size of the nano-crystals are determined by combining scattering, microscopic and spectral techniques.
View Article and Find Full Text PDFWe demonstrate time-correlated single photon counting (TCSPC) in microfluidic droplets under high-throughput conditions. We discuss the fundamental limitations in the photon acquisition rate imposed by the single photon detection technique and show that it does not preclude accurate fluorescence lifetime (FLT) measurements at a droplet throughput exceeding 1 kHz with remarkable sensitivity. This work paves the way for the implementation of innovative biomolecular interaction assays relying on the FLT detection of nanosecond-lived fluorophores for high-throughput biotechnological applications, including high-throughput screening or cell sorting potentially allowed by droplet microfluidics or other fast sample handling facilities.
View Article and Find Full Text PDFA strong non linear relationship between nitrate and organic matter (assessed by dissolved organic carbon, DOC) has been recently demonstrated by Taylor and Townsend (2010), namely for freshwaters. In this context, our study explores this relation from the behavior of sets of normalized UV spectra (same area under each spectrum) of different water samples showing a hidden isosbestic point (HIP) around 225 nm. This HIP is linked to the existence of a simple relation between nitrate and DOC, the proportions of which vary according to the sampling location and environmental factors.
View Article and Find Full Text PDFUnlabelled: Providing an easy ingress-egress (I/E) movement remains a challenge for car designers. I/E has been largely studied in kinematics, but not in dynamics. This study proposes: (1) to evaluate and describe the motor torques developed in the lower limbs and lumbar joints during I/E motions and (2) to analyse the influence of the car geometry and subject anthropometry.
View Article and Find Full Text PDFThis paper presents a general method to estimate unmeasured external contact loads (ECLs) acting on a system whose kinematics and inertial properties are known. This method is dedicated to underdetermined problems, e.g.
View Article and Find Full Text PDFUnlabelled: This study aimed at experimentally investigating the influence of roof height and sill width on car ingress/egress movements. The first uncomfortable (Ht1) and the lowest acceptable (Ht2) roof heights were obtained from 26 participants of three different stature groups thanks to a multi-adjustable vehicle mock-up. Both Ht1 and Ht2 were affected neither by stature nor by vehicle type.
View Article and Find Full Text PDFWe have studied the solubilization behavior of tributylphosphate (TBP) in aqueous solutions of L64-Pluronics, using light and small angle neutron scattering (SANS). Varying the temperature and the oil content, the system presents a nontrivial phase behavior. In particular, at 308 K, a first solubilization followed by an emulsification failure and a resolubilization is found.
View Article and Find Full Text PDFThe solubilization of tributylphosphate (TBP), a polar oil, in various micellar solutions of Pluronic has been investigated by (1)H NMR spectroscopy. Partial phase diagrams of the three components systems (Pluronic-TBP-water) have shown two characteristic temperatures, called CPT and SMT, which control the phase behavior (see Part I); Both temperature depend on the copolymer structure and, interestingly, are directly related to the TBP concentration in the medium. Monophasic microemulsions are observed only when the temperature ranges between the SMT and the CPT.
View Article and Find Full Text PDFSolubilization of tributylphosphate (TBP), a polar oil, in various micellar solutions of Pluronic has been investigated by turbidimetry emphasizing the effect of temperature and the role of the PPO and PEO blocks on the phase behavior of the three components systems (Pluronic-TBP-water). [Temperature-composition] diagrams allow monophasic and diphasic domains to be delimited. Two temperatures are shown to have a determining effect on the phase behavior (TBP solubilization); the well known cloud point temperature (CPT, here defined for the three components system) and the solubilization minimum temperature (SMT) which is defined as the lowest temperature allowing solubilization of TBP in the system.
View Article and Find Full Text PDFAn analysis of the cellular and humoral immune responses after bacille Calmette-Guerin (BCG) vaccination and during tuberculosis treatment favors the hypothesis of an immune defence developed in four overlapping successive stages. The initial immune response is innate. The following two intermingle innate and specific responses against low molecular weight oligopeptidic and nonpeptidic antigens, as muramyldipeptide and trehalose dimycolate, and large molecular weight nonpeptidic antigens such as lipoarabinomannan.
View Article and Find Full Text PDFEar Nose Throat J
April 1997
During surgery for otosclerosis, it is common for the surgeon to cut the stapedius tendon. Even without reconstruction of the tendon, the results of this kind of surgery are particularly satisfactory. The stapedial reflex is more important for improving intelligibility of speech in the presence of background noise than for protection against hazardous levels of noise.
View Article and Find Full Text PDFThe authors describe the various surgical indications and techniques of the argon laser and Gherini-Causse Endo-Otoprobe in otologic surgery, from otosclerosis to chronic otitis. The advantages are numerous, permitting the surgeon to vaporize or coagulate tissue with optimal effect, avoiding excessive mobilization of the ossicular chain and diminishing the risk of damage to the facial nerve and inner ear structures.
View Article and Find Full Text PDFBackground: The glycoproteic hormones, LH and FSH, circulate under heterogenous molecular forms, the isoforms. The more acidic isoforms of FSH are found in hypogonadic patients and a displacement towards the basic forms is observed during substitutive treatment.
Case Report: A 13 year-old girl with Turner syndrome was examined for pubertal delay.
The enigmas and paradoxes observed in tuberculous patients, in Bacille Calmette-Guérin-vaccinated people and in Bacille Calmette-Guérin-treated cancer patients have been examined, in an attempt to explain them through the mechanisms of immunodeficiency and immunosuppression. A dual effect is postulated: an immunosuppression induced by the infecting mycobacteria that adds to a pre-existing or emerging state of immunodeficiency of the infected individual. The immunological cellular and humoral anergies observed at the beginning of a tuberculous therapy are usually lifted after the first two weeks of treatment.
View Article and Find Full Text PDFIn our experience, tinnitus for otosclerosis may be due to the following: poor vibration of the inner ear fluids, fixation of the footplate, destruction of the Corti hair cells by the proteolytic enzymes, acoustic trauma, or to poor inner ear blood supply due to the hyalinization of the spiral ligament of the stria vascularis. The aim of this article is to suggest some explanations to enhance future research work carried out by other authors on this important issue, and to show what are the results of surgery in our experience, as far as tinnitus is concerned. Only complete release of the tinnitus one year after surgery is taken into account to assess the results.
View Article and Find Full Text PDFTinnitus due to otosclerosis may be caused by poor vibration of the inner ear fluids. The goal of this article is to suggest some explanations, to enhance future research work carried out by other authors on this important issue, and to show what are the results of surgery to relieve tinnitus in the author's experience. Only complete resolution of the tinnitus 1 year after surgery was taken into account in the assessment of the results.
View Article and Find Full Text PDFOtolaryngol Clin North Am
August 1994
Aeration of a mucosa-lined tympanic cavity is essential for a functioning middle ear. Extrusions of even the best-designed prostheses occur from abnormal middle ear conditions such as atelectasis, middle ear fibrosis, recurrent cholesteatoma, tympanic membrane perforation, and otitis media. Various polymers have been developed in an attempt to maximize prosthetic biocompatibility and ease of use while minimizing the chance of extrusion.
View Article and Find Full Text PDFThe resistance rebuilt around the lower tip of the piston must be the same as that created by the annular ligament of the stapes footplate. Otherwise, the threshold at which an acoustic or barotrauma is able to damage the membranes and hair cells of the inner ear will be lowered. The elasticity reestablished around the lower tip of the piston plays a part in the quality and quantity of hearing for the low frequencies up to 3 kHz.
View Article and Find Full Text PDFAs a medical treatment for otospongiosis-otosclerosis, sodium fluoride influences the underlying bony changes in the labyrinth so as to arrest or prevent the onset of hearing loss. Sodium fluoride is an enzyme inhibitor and reduces osteoclastic bone resorption and, if the dosage is more than 60 mg a day, may rebuild pseudohaversian bone.
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