Presence of lipids in urine, crystals and stones: Implications for the formation of kidney stones

Presence of lipids in urine, crystals and stones: Implications for the formation of kidney stones.BackgroundCell membranes and their lipids play critical roles in calcification. Specific membrane phospholipids promote the formation of calcium phosphate and become a part of the organic matrix of growing calcification. We propose that membrane lipids also promote the formation of calcium oxalate (CaOx) and calcium phosphate (CaP) containing kidney stones, and become a part of their stone matrix.MethodsHuman urine, crystals of CaOx and CaP produced in the urine of healthy individuals, and urinary stones containing struvite, uric acid, CaOx and CaP crystals for the presence of membrane lipids were analyzed. Crystallization of CaOx monohydrate at Langmuir monolayers of dipalmitoylphosphatidylglycerol (DPPG), dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylserine (DPPS), dioleoylphosphatidylglycerol (DOPG), palmitoyloleoylphosphatidylglycerol (POPG) and dimyristoylphosphatidylglycerol (DMPG) was investigated to directly demonstrate that phospholipid assemblies can catalyze CaOx nucleation.ResultsUrine as well as CaOx and CaP crystals made in the urine and various types of urinary stones investigated contained some lipids. Urine of both CaOx and uric acid stone formers contained significantly more cholesterol, cholesterol ester and triglycerides than urine of healthy subjects. However, urine of CaOx stone formers contained more acidic phospholipids. The organic matrix of calcific stones contained significantly more acidic and complexed phospholipids than uric acid and struvite stones. For each Langmuir monolayer precipitation was heterogeneous and selective with respect to the orientation and morphology of the CaOx crystals. Crystals were predominantly monohydrate, and most often grew singly with the calcium rich (10-1) face toward the monolayer. The number of crystals/mm2 decreased in the order DPPG> DPPC and was inversely proportional to surface pressure and mean molecular area/molecule.ConclusionsStone forming conditions in the kidneys greatly impact their epithelial cells producing significant differences in the urinary lipids between healthy and stone forming individuals. Altered membrane lipids promote face selective nucleation and retention of calcium oxalate crystals, and in the process become a part of the growing crystals and stones

The Magnetic Spin Ladder (C_{5}H_{12}N)_{2}CuBr_{4}: High Field Magnetization and Scaling Near Quantum Criticality

The magnetization, $M(H \leq 30$ T, 0.7 K $\leq T \leq 300$ K), from single crystals and powder samples of (C$_{5}$H$_{12}$N)$_{2}$CuBr$_{4}$ has been used to identify this system as an $S=1/2$ Heisenberg two-leg ladder in the strong coupling limit, $J_{\perp} = 13.3$ K and $J_{\parallel} = 3.8$ K, with $H_{c1} = 6.6$ T and $H_{c2} = 14.6$ T. An inflection point in $M(H, T = 0.7$ K) at half-saturation, $M_{s}/2$, is described by an effective \emph{XXZ} chain. The data exhibit universal scaling behavior in the vicinity of $H_{c1}$ and $H_{c2}$, indicating the system is near a quantum critical point.Comment: 4 pages, 4 figure

Chimie intégrative : un outil pour la synthèse rationnelle de matériaux avancés

Dossier Techniques de l'Ingénieur RE 173Les sciences chimiques, en perpétuelle évolution, sont associées à des synthèses de plus en plus complexes et transdisciplinaires. Dans ce contexte, nous montrons comment la chimie intégrative parvient à compartimentaliser les réacteurs chimiques au travers de réactions déclenchées aux interfaces huile/eau d'émulsions diluées (réacteurs chimiques dispersés) et concentrées (réacteurs chimiques en contact). Pour illustrations, quelques exemples non exhaustifs de morphosynthèses de matériaux fonctionnels avancés sont donnés dans les domaines de la biocatalyse hétérogène, de la conversion d'énergie et du relargage thermostimulé de substances d'intérêt encapsulées

LiBH4@Carbon Micro-Macrocellular Foams: Tuning Hydrogen Release through Varying Microporosity

Microporous-macroporous carbononaceous monolith-type materials, prepared through a hard template method using silica as exo-templating matrices, have been impregnated by an etheric solution of LiBH4 to prepare LiBH4@Carbon samples. It has been shown that the amorphous character of LiBH4 is largely favoured when developing the carbon microporosity (pores smaller than 2 nm) and that LiBH4 dehydrogenation is strongly enhanced at low temperatures. The onset temperature of dehydrogenation can be decreased to 200°C and hydrogen capacity reaching 4.0 wt.% is obtained at 300°C with the carbon having the largest microporous volume, whereas the hydrogen release for bulk LiBH4 is negligible at the same temperature. In addition to some irreversible reactions with carbon surface groups the explanation for such modification could lie in the LiBH4 destabilization through confinement to the nanoscale range and associated amorphization

: Advanced functional cellular materials bearing multiscale porosity

With this mini review we show through the sol-gel and emulsion-based Integrative Chemistry how it is possible to trigger materials dimensionality and beyond their functionalities when reaching enhanced applications. In here we focus on 3D macrocellular monolithic foams bearing hierarchical porosities and applications thereof. We first depict the general background of emulsions focusing on concentrated ones, acting as soft templates for the design of PolyHIPE foams, HIPE being the acronym of High Internal Phase Emulsions while encompassing both sol-gel and polymer chemistry. Secondly we extend this approach toward the design of hybrid organic-inorganic foams, labeled Organo-Si(HIPE), where photonics and heterogeneous catalysis applications are addressed. In a third section we show how inorganic Si(HIPE) matrices can be employed as sacrificial hard templates for the generation carbonaceous foams, labeled Carbon(HIPE). These foams being conductive we show applications when employed as electrodes for Li-S battery and as hosts for Li(BH4)-based hydrogen storage

Gold nanoparticles spontaneously generated in onion-type multilamellar vesicles. Bilayers-particle coupling imaged by Cryo-TEM

We report the spontaneous, in-situ synthesis of gold nanoparticles within onion-type multilamellar vesicles (MLV) using a simple and mild strategy. Monoolein, one of the MLV components, was used as reductant, without any additional chemical. Two different preparative pathways were employed that resulted in gold particle formation as asserted by UV-vis spectroscopy and transmission electron microscopy (TEM). When onions were prepared from a lamellar phase containing gold ions, nanoparticles with a rice grain shape and narrow size distribution (6 × 10 nm*nm) were formed, suggesting synthesis within the vesicles. When preformed onions were dispersed in a KAuCl4 solution, TEM and cryogenic temperature-transmission electron microscopy (cryo-TEM) analysis reveal that both extra- and intravesicular syntheses took place. Cryo-TEM imaging evidences the insertion of gold nanoparticles between MLV leaflets and the close coupling between particle morphology and the lamellar phase. A simple mechanism of particle growth within a lamellar phase is proposed that could explain the differences in nanoparticle size and shape observed between both preparative pathways

Millifluidic as a versatile reactor to tune size and aspect ratio of large polymerized objects

The continuous production "on demand" of large polymerized objects is presented using a versatile, easy to implement and low cost "millifluidic" reactor. Over microfluidic devices, the present set-up offers two considerable advantages: (i) much larger particles are produced with a very good control of sizes and shapes and (ii) no lithography is required for its design. Considering the high modularity of this synthetic pathway, "tubular millifluidic" appears as a new concept of synthesizing particles with a strong control over final object sizes, monodispersity and aspect ratio. The possibility to reach a high scale production makes it a promising production tools for the industry

Molecular design of nanostructured boron nitride

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Integrative Sol-Gel Chemistry

Integrative chemistry is the link between the notions of “complexity in chemistry” and the bio-inspired integrative synthesis. This chapter relies on this vein of integrative chemistry, while dealing with sol-gel chemistry. Through the sol–gel-based integrative chemistry, it shows how it is possible to trigger materials dimensionality and beyond their functionalities when reaching enhanced applications. Thereby it selectively proposes the morphosyntheses of discrete objects, 1D materials (fibers), 2D arrays (films), and 3D macrocellular foams bearing hierarchical porosities (monoliths). The chapter discusses in detail how integrative chemistry allows fine-tuning of material shapes and dimensions while offering enhanced applications. Considering the shaping modes, it also deals with how the integrative chemistry allows positioning the chemical reactors within the geometric spaces, with specific competence appearing as a novel paradigm with regard to traditional sol-gel chemistry