Hydrophilic Elements Research Articles

The potential of sonocrystallization in crystal habit modification for improving micromeritic and physicochemical properties of Dapagliflozin

Dapagliflozin propanediol monohydrate (DAPA), an antidiabetic drug owing to its needle-shaped crystals exhibits poor micromeritic and physicochemical properties. Crystal habit modification by conventional and sonocrystallization approaches was employed to improve its manufacturability. SEM analysis of sonocrystallized DAPA in acetonitrile (DAPA_SNC3) revealed a rod habit with lower aspect ratio (3.56±0.91) and narrow size distribution (span value-1.37). In case of DAPA_EH and DAPA_CS (solvent evaporation in ethanol:n-hexane, and chloroform, respectively), rod and plate-shaped crystals were obtained with aspect ratios 6.98±5.84 and 6.03±4.21, respectively. All three samples showed significantly improved powder flowability (p<0.0001) compared to DAPA. Further solid-state characterization by FTIR, TGA, DSC, and PXRD showed no polymorphic changes in recrystallized samples. The contact angle studies in water revealed wetting tendency in the following order: SONO_SNC3>SONO_EH>SONO_CS>DAPA. Polar energies of DAPA_SNC3 and DAPA_CS were significantly higher (p<0.01 & p<0.001, respectively) when compared with DAPA. The XPS studies showed increased hydrophilic elements on the surfaces of DAPA_SNC3 crystals which resulted in improved wettability. DAPA_SNC3 among all samples showed highest tensile strength at 200 MPa compression force because of its shape. DAPA_EH showed no significant improvement in IDR profile, while DAPA_CS and DAPA_SNC3 showed significantly faster IDR because of prominent polar functionality (p<0.05 and p<0.0001, respectively).

Advancements in Cotton Textile Design: Addressing Temperature and Moisture Challenges

The primary objective of this study is to alleviate discomfort arising from fluctuations in heat and humidity due to environmental and personal factors, aiming to develop functional textiles capable of effectively responding to these changes. To achieve this, systematic pattern designs were implemented on 100% cotton woven fabrics, incorporating hydrophobic characteristics through the application of a water-repellent agent to specific areas. The resulting compatibility of these hydrophobic features with hydrophilic elements endowed the fabrics with moisture management properties. Furthermore, the introduction of a phase-changing material agent to these fabrics imparted heat management capabilities. The rotation printing technique was employed to seamlessly transfer these agents onto the fabric. In assessing the durability of woven fabrics featuring distinct functionalities, a comprehensive examination was conducted, subjecting them to 30 repeated wash cycles within a single process step. The morphological structures of the fabrics produced were meticulously analyzed using SEM (scanning electron microscopy), SEM–EDX (energy-dispersive X-ray analysis) while their chemical compositions were scrutinized through FTIR–ATR (Fourier transform infrared spectroscopy–attenuated total reflectance). Additionally, a battery of tests, including physical, chemical, liquid absorption, liquid transfer assessments, and DSC (differential scanning calorimetry) analyses, were conducted in accordance with relevant standards. The outcomes of this study demonstrated that the fabrics not only met the criteria of the TS 866 standard, particularly with regard to a rapid response time of less than 10 s, but also exhibited resilience to repeated washings, affirming the enduring efficacy of the incorporated functionalities. According to tearing strength results, slight increase was also observed in treated cotton fabrics.

Miocene (Burdigalian) coastal lowland vegetation and palaeoclimate based on a palaeoenvironmental reconstruction of the Els Cardscolers site, Majorca, Spain

The early Miocene (Burdigalian) macroflora of the Els Cardscolers site (Majorca Island, Balearic Islands province, Spain) is studied here from a palaeoecological and taxonomical perspective. The study shows the presence of a palaeotropical flora with thermophilic and hygrophilic elements characteristic of a coastal wetland environment, formed by monocotyledons, Lygodium gaudinii, palms (Sabalites sp.), a predominance of shrubs with Myrica lignitum and the presence of accessory elements such as Berberis kymeana, Engelhardia orsbergensis, Ziziphus paradisiaca, Sapotacites minor and Myrica longifolia. Arboreal taxa like Lauraceae or Fagaceae and some Fabaceae species were also present. The temperature values obtained by CLAMP analysis are as follows: MAT: 17.6–19.9 °C, WMMT: 24.3–27.07 °C, and CMMT: 10.4–14.2 °C. These findings suggest a warm climate with little temperature seasonality. Precipitation values (e.g., GSP, MMGSP, Three_WET, and Three_DRY) suggest the absence of a summer-dry regime although a clear contrast in precipitation is inferred. The inferred climate is similar to that of other coeval regions of Southern Europe, although it stands out for its high values of CMMT. It is similar to the climate of the island of Evia in Greece. From a floristic point of view, the Els Cardscolers flora is similar to the Burdigalian site of Cristo Rei (Portugal), and a clear relationship with the floral complex of Ipolytarnóc-Luzern (Hungary) also can be inferred.

Application of chlorhexidine and its effect on hybrid layers: A review of the literature

Background: Adhesion must occur between the demineralized organic mass of the tooth structure and the hydrophilic elements of the adhesive resin. The goal of achieving clinical success with this procedure is clearly expressed in the recommendations for the application of the acidifying and bonding materials, as well as in the rules that appear under the dental material manufacturing brand. Bonding the composite with demineralized dental structures is a procedural technique that relies on the sensitive mechanism of adhesion between the hydrophobic and hydrophilic parts of the resin and the dental organic matrix after acidification. The clinical success of the application is then expressed through the longevity of the filling and the absence of secondary or subsequent complications. Materials and Methods: This study is a literature review. A total of 54 articles were selected, of which 12 were excluded from further evaluation as they did not meet one or more of the inclusion criteria in the study. Therefore, 42 articles were included as the base articles for this study. Results: Chlorhexidine (CHX) was applied after rinsing the acid with water and air-drying the dentin only on a wet surface. This method is the only clinically proven one, as it is easy to apply and likely to gain wider acceptance initially. However, research is expected to develop simpler and more efficient methods of applying CHX or other matrix metalloproteinase inhibitors. For instance, a recent in vitro study demonstrated that the addition of 2% CHX to a conventional 37% phosphoric acid prevented the degradation of bond strength in an “Etch and Rinse” adhesive system over a 6-month period. Conclusion: The clinical application of 2% CHX for 1 min on acidified dentin, following an acid rinse and before the application of dentin primer and bond, has been shown to effectively prevent significant in vivo degradation of bond strength by metalloproteinases for a minimum of 14 months.

Molecular Mechanism Study on the Effect of Microstructural Differences of Octylphenol Polyoxyethylene Ether (OPEO) Surfactants on the Wettability of Anthracite.

Inhalable coal dust poses a serious threat to coal mining safety, air quality, and the health of miners. Therefore, the development of efficient dust suppressants is crucial for addressing this issue. This study evaluated the ability of three high-surface-active OPEO-type nonionic surfactants (OP4, OP9, and OP13) to improve the wetting properties of anthracite via extensive experiments and a molecular simulation and determined the micro-mechanism of different wetting properties. The surface tension results show that OP4 has the lowest surface tension (27.182 mN/m). Contact angle tests and wetting kinetics models suggest that OP4 exhibits the strongest wetting improvement ability on raw coal with the smallest contact angle (20.1°) and the fastest wetting rate. In addition, FTIR and XPS experimental results also reveal that OP4-treated coal surfaces introduce the most hydrophilic elements and groups. UV spectroscopy testing shows that OP4 has the highest adsorption capacity on the coal surface, reaching 133.45 mg/g. The surfactant is adsorbed on the surface and pores of anthracite, while the strong adsorption ability of OP4 results in the least amount of N2 adsorption (8.408 cm3/g) but the largest specific surface area (1.673 m2/g). In addition, the filling behavior and aggregation behavior of surfactants on the anthracite coal surface were observed using SEM. The MD simulation results indicate that OPEO reagents with overly long hydrophilic chains would produce spatial effects on the coal surface. Under the influence of the π-π interaction between the hydrophobic benzene ring and the coal surface, OPEO reagents with fewer ethylene oxide quantities are more prone to adsorb onto the coal surface. Therefore, after the adsorption of OP4, both the polarity and the water molecule adhesion ability of the coal surface are greatly enhanced, which helps to suppress dust production. These results provide important references and a foundation for future designs of efficient compound dust suppressant systems.

Synthetic O-Acetylated Sialosides and their Acetamido-deoxy Analogues as Probes for Coronaviral Hemagglutinin-esterase Recognition.

O-Acetylation is a common modification of sialic acids that can occur at carbons 4-, 7-, 8-, and/or 9. Acetylated sialosides are employed as receptors by several betacoronaviruses and toroviruses, and by influenza C and D viruses. The molecular basis by which these viruses recognize specific O-acetylated sialosides is poorly understood, and it is unknown how viruses have evolved to recognize specific O-acetylated sialosides expressed by their host. Here, we describe a chemoenzymatic approach that can readily provide sialoglycan analogues in which acetyl esters at C4 and/or C7 are replaced by stabilizing acetamide moieties. The analogues and their natural counterparts were used to examine the ligand requirements of the lectin domain of coronaviral hemagglutinin-esterases (HEs). It revealed that HEs from viruses targeting different host species exhibit different requirements for O-acetylation. It also showed that ester-to-amide perturbation results in decreased or loss of binding. STD NMR and molecular modeling of the complexes of the HE of BCoV with the acetamido analogues and natural counterparts revealed that binding is governed by the complementarity between the acetyl moieties of the sialosides and the hydrophobic patches of the lectin. The precise spatial arrangement of these elements is important, and an ester-to-amide perturbation results in substantial loss of binding. Molecular Dynamics simulations with HEs from coronaviruses infecting other species indicate that these viruses have adapted their HE specificity by the incorporation of hydrophobic or hydrophilic elements to modulate acetyl ester recognition.

Low Fouling Polysulfobetaines with Variable Hydrophobic Content.

Amphiphilic polymer coatings combining hydrophilic elements, in particular zwitterionic groups, and hydrophobic elements comprise a promising strategy to decrease biofouling. However, the influence of the content of the hydrophobic component in zwitterionic coatings on the interfacial molecular reorganization dynamics and the anti-fouling performance is not well understood. Therefore, coatings of amphiphilic copolymers of sulfobetaine methacrylate 3-[N-2'-(methacryloyloxy)ethyl-N,N-dimethyl]-ammonio propane-1-sulfonate (SPE) are prepared which contain increasing amounts of hydrophobic n-butyl methacrylate (BMA). Their fouling resistance is compared to that of their homopolymers PSPE and PBMA. The photo-crosslinked coatings form hydrogel films with a hydrophilic surface. Fouling by the proteins fibrinogen and lysozyme as well as by the diatom Navicula perminuta and the green algae Ulva linza is assessed in laboratory assays. While biofouling is strongly reduced by all zwitterionic coatings, the best fouling resistance is obtained for the amphiphilic copolymers. Also in preliminary field tests, the anti-fouling performance of the amphiphilic copolymer films is superior to that of both homopolymers. When the coatings are exposed to a marine environment, the reduced susceptibility to silt incorporation, in particular compared to the most hydrophilic polyzwitterion PSPE, likely contributes to the improved fouling resistance.

Pore network simulations of liquid water and oxygen transport in gas diffusion layers with spatially variable wettability

The wettability modification of the gas diffusion layer has a significant effect on water management in proton exchange membrane fuel cells. Therefore, a three-dimensional regular pore network model is developed to numerically investigate the liquid water and oxygen transport in gas diffusion layer with spatially variable wettability. Four types of hydrophilicity configuration are taken into account: uniform configuration, symmetric graded configuration, positive graded configuration and negative graded configuration. Pore-scale analysis shows that adding hydrophilic elements first enhances liquid-gas transport and then decreases. There is an optimum hydrophilic pore fraction (fc) leading to minimum liquid water saturation and maximum limiting current density in each wettability configuration, and the value of fc is related to wettability configuration and gradient but independent of inlet injection points. In addition, the results reveal that oxygen transport not only depends on total liquid water saturation, but also depends on water distribution. Uniform water distribution in the through-plane direction is helpful for oxygen transport, so the gas diffusion layer with positive graded hydrophilicity configuration obtains the highest limiting current density.

Hydrophobic-hydrophilic crown-like structure enables aquatic insects to reside effectively beneath the water surface

Various insects utilise hydrophobic biological surfaces to live on the surface of water, while other organisms possess hydrophilic properties that enable them to live within a water column. Dixidae larvae reside, without being submerged, just below the water surface. However, little is known about how these larvae live in such an ecological niche. Herein, we use larvae of Dixa longistyla (Diptera: Dixidae) as experimental specimens and reveal their characteristics. A complex crown-like structure on the abdomen consists of hydrophobic and hydrophilic elements. The combination of these contrasting features enables the larvae to maintain their position as well as to move unidirectionally. Their hydrophobic region leverages water surface tension to function as an adhesive disc. By using the resistance of water, the hydrophilic region serves as a rudder during locomotion.

Recycling of spent industrial soil in manufacturing process of clay brick

The present study aimed to investigate the feasibility of using Spent Industrial Soil (SIS) generated in the process of Aromatics production in manufacturing clay brick. The physicochemical properties of raw clay and SIS were analyzed using different lab tests such as X-ray Fluorescence (XRF) and X-ray diffraction (XRD). Six different amounts of SIS (i.e. 0, 5, 10, 15, 20 and 25 % by weight) were mixed with clay soil and fired by electric furnaces at 950 °C for 8 h to make fired brick samples. Magnified images were taken using Scanning Electron Microscope (SEM) for all samples to indicate the significant changes in pores size due to adding SIS. The results showed that SIS increases the water absorption and water suction and reduces the density of brick samples due to increasing porosity in the structure of brick. Also the linear shrinkage is reduced in samples containing SIS and this finding is justified by the lower amounts of hydrophilic elements (i.e. Ca, Mn, and Mg) in SIS, compared with raw clay soil. On the other hand, the compressive strength of brick samples which is affected by both porosity and SiO2 amount has been increased by mixing SIS content of 20 %. Thus using SIS in clay brick construction is an effective way to make a porous and lighter brick which meets the required standards of structural and environmental issues.

Thermoresponsive Nanogels of Modified Poly((di(ethylene glycol) methyl ether methacrylate)-co-(2-aminoethyl methacrylate))s

A series of copolymers of di(ethylene glycol) methyl ether methacrylate (D) and 2-aminoethyl methacrylate (A) (P(D-co-A)) with variable ratios of comonomers were synthesized using atom transfer radical polymerization. Then, the amino groups of obtained copolymers were modified to clickable azide or prop-2-yn-1-yl carbamate groups. A thermoresponsive copolymers were obtained with the value of cloud point temperature (TCP) dependent on the type and number of functional groups in the copolymer and on the concentration of solutions. For P(D-co-A) copolymers, the TCP increased with increasing content of 2-aminoethyl methacrylate comonomer. The presence of azide and prop-2-yn-1-yl carbamate groups caused the changes of TCP of modified copolymers. All studied copolymers in dilute aqueous solutions aggregated above TCP to nanoparticles with sizes dependent on the solution concentration, heating procedures, and types and numbers of functional groups present in a copolymer chain. The presence of hydrophilic elements in the chain and the increase in the copolymer concentration led to the enlargement of the particle sizes. Aggregates were crosslinked using click reaction between an azide and prop-2-yn-1-yl carbamate groups that led to stable thermoresponsive nanogels. A systematic study of the behavior of copolymers allowed the determination of the chains useful for possible application in drug delivery.

Sphenopsid and fern remains from the Upper Triassic of Krasiejów (SW Poland)

Hydrophilic elements, such as sphenopsids and ferns, are rare in the flora of the Krasiejow site and they are poorly preserved. One sphenopsid species, Neocalamites merianii , was recognised. It is preserved as impressions, flattened casts, moulds and isolated leaves. So far, only one small fern specimen, determined as Sphenopteris sp., has been found. These elements probably were transported to the site of deposition and did not grow where they were buried.

Whole cigarette smoke condensates induce ferroptosis in human bronchial epithelial cells

Cigarette smoke is responsible for many fatal pulmonary diseases, however, the toxic mechanism is still unclear. In this study, we first confirmed that whole cigarette smoke condensates (WCSC) contain hydrophilic elements, lipophilic and gaseous components. Then, we treated BEAS-2B cells, a normal human bronchial epithelial cell line, at dosages of 0.25, 0.5, and 1% for 24 h and explored the toxic mechanism. Cell viability decreased in a dose-dependent manner, and fission and fusion of mitochondria, damage of endoplasmic reticulume (ER) structures, and formation of autophagosome-like vacuoles were found in cells treated with 1% WCSC. Mitochondrial and ER volumes, lysosomal fluorescence intensity, LDH release, and intracellular ROS levels notably decreased at the highest doses compared with the control, whereas intracellular calcium ion and NO levels were significantly elevated accompanying G2/M phase arrest. Expression of an iron-binding nuclear protein-related gene (pirin) was the most up-regulated in the WCSC-treated cells with enhanced expression of antioxidant-related genes, whereas expression of carbonic anhydrase IX gene, a marker of tumor hypoxia, was the most down-regulated. Additionally, levels of apoptosis (BAX, Apaf-1, and cleavage of caspase-3 and PARP), autophagy (p62 and LC3B-II), ER stress (PERK, IRE-1a, Bip, and CHOP), antioxidant (SOD-1 and SOD-2), and MAPkinase activation (p-ERK, p-p38, and p-JNK)-related proteins were clearly enhanced following exposure to WCSC, whereas expression of several mitochondrial dynamics-related proteins was reduced with dose. Interestingly, expression of ferritin protein (light chain) was dramatically enhanced near the ER along with that of p62 protein. More importantly, the hypoxia inducible factor-1 pathway and ferroptosis were proposed among the 20 terms in KEGG pathway analysis, and secretion of IL-6 and IL-8, which are involved in hypoxia-induced inflammation, were clearly elevated with dose. Taken together, we suggest that WCSC may induce ferroptosis in bronchial epithelial cells via ER stress and disturbed homeostasis in mitochondrial dynamics caused by induction of hypoxia conditions.

La Laguna Conceja (Lagunas de Ruidera): medio natural y fondo subacuático

Este trabajo desarrolla una metodología geográfica novedosa destinada al conocimiento del medio natural en un entorno lacustre. En ella converge la información de los análisis de campo y observaciones subacuáticas junto al estudio de fuentes históricas. Esta dualidad metodológica permite aportar datos inéditos provenientes de los fondos lacustres y contrastar las repercusiones que en ellos han tenido los usos de suelo en las vertientes. Se ha aplicado a la Laguna Conceja, una de las más emblemáticas de las Lagunas de Ruidera. Sin embargo, a pesar de haber sido objeto de investigaciones desde variadas perspectivas científicas, todavía falta conocer la evolución reciente experimentada por su entorno, el estado de las cubiertas vegetales ubicadas en vertientes y orillas, así como el paisaje de sus fondos. Como resultado se ha determinado la morfología de la cubeta lacustre, la presencia de replanos sumergidos de toba, la naturaleza lutítica de los sedimentos de su fondo, la localización de surgencias subacuáticas y la identificación de elementos higrófilos no mencionados hasta el presente; finalmente, las agresiones sufridas, durante los últimos siglos, por las cubiertas vegetales apenas han dejado importantes acúmulos de terrígenos que amenacen la colmatación y la futura funcionalidad de los procesos de precipitación en esta laguna tobácea.

Humidity sensor based on solution processible microporous silica nanoparticles

Composites fabricated by mesoporous silica loading hydrophilic elements have been widely investigated as humidity sensitive materials. The physical mixing process for loading hydrophilic elements is difficult to guarantee the uniformity and structural stability of the composites. Furthermore, the poor dispersibility of the silica skeleton restricts its solution processability. Herein, solution processible organic-inorganic hybrid materials were synthesized via a thiol-ene click reaction between sulfhydryl functionalized microporous silica nanoparticles (MSNs) and hydrophilic alkenyl monomer. The optimal hybrid material could disperse in water stably with a concentration of 50 mg/mL owing to the small particle size (about 105 nm) and the hydrophilic characteristic. Humidity sensors were fabricated by solution process and the humidity sensing properties were investigated. The sensor exhibits high sensitivity (about three orders impedance modulus change), small hysteresis (∼2% RH) and rapid response (the response and recovery time are 5 and 40 s, respectively) in the humidity range of 11%–95% RH.

The Chemical Design and Synthesis of Linkers Used in Antibody Drug Conjugates.

Antibody Drug Conjugates (ADCs) use targeting ability of monoclonal antibodies to deliver potent cytototoxic payloads to their intended target. The linker encompasses a conjugating functionality suitable for attachment to the antibody, a spacer unit that typically incorporates a hydrophilic element and a trigger which releases the potent cytototoxic warhead. Understanding the conflicting requirements of ADC design, providing stability in systemic circulation but efficient payload release once the ADC reaches its intended target, is crucial to effective linker development. ADC linker design has been approached in a variety of different ways, with increasingly elegant solutions continuing to be reported as understanding of the intricate design complexities increases. This review focuses on the synthetic approaches used in ADC linkers, and the impact of linker design on antibody conjugation, ADC pharmacokinetics and payload release. Linker approaches utilized in commercial ADCs as well as ADCs currently in clinical, pre-clinical and early stage development are discussed.

Pore-network simulations of two-phase flow in a thin porous layer of mixed wettability: Application to water transport in gas diffusion layers of proton exchange membrane fuel cells

Pore network simulations are performed to study water transport in a model gas diffusion layer (GDL) of polymer electrolyte membrane fuel cells (PEMFCs) in relation with the change in hydrophobicity that might be due to aging or temperature effect. The change in hydrophobicity is taken into account by changing randomly the fraction of hydrophilic elements, pores or throats, in the network. The transport and equilibrium properties of the model GDL are computed as a function of liquid saturation as well as at breakthrough varying the fraction of hydrophilic elements. The results indicate that the hydrophilic element percolation threshold marks the transition between two domains. The system is found to be weakly dependent on the fraction of hydrophilic elements as long as this fraction is below the percolation threshold whereas an increase in wettability above the percolation threshold favours a greater blockage of the pore space by the water and therefore a diminished access of gas to the catalyst layer. This model may help assess the effect of a change in wettability on the fuel cell performance and may also help suggest better GDL designs in relation with the water management problem in PEMFCs.

Fabrication of Synaptotagmin II-Functionalized Neuromimetic Copolymeric Nanomembranes

Nanoscale copolymer membranes that mimic the innate structure and properties of biological lipid membranes possessing hydrophilic and hydrophobic elements to support protein folding were used for a fundamental examination of protein—polymer integration. This study has integrated the neural synaptotagmin II (Syt II) protein, a documented target of the hemagglutinin-33 (Hn-33) protein associated with botulinum neurotoxin type A during the infection process, into polymethyloxazoline—polydimethylsiloxane—polymethyloxazoline nanomembranes. By integrating Syt II into block copolymer membranes, we have developed a neural mimetic membrane toward Hn-33 targeting the applications in nanomaterial-mediated detection. This technology can serve as a robust stand-alone platform for toxin diagnostic studies, or as a coating for integration with micro-/nanofabricated devices and electrodes for protein—protein interaction-based detection. To assess enhanced membrane complexity and toxin specificity, studies assessing the co-insertion of trisialoganglioside-GT1b (GT1b) and Syt II into the nanomembranes were used as a subsequent platform for botulinum neurotoxin type B detection. Protein—membrane integration was confirmed with atomic force microscopy imaging, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Langmuir isotherm analysis.

A comprehensive classification system for lipids

Lipids are produced, transported, and recognized by the concerted actions of numerous enzymes, binding proteins, and receptors. A comprehensive analysis of lipid molecules, "lipidomics," in the context of genomics and proteomics is crucial to understanding cellular physiology and pathology; consequently, lipid biology has become a major research target of the postgenomic revolution and systems biology. To facilitate international communication about lipids, a comprehensive classification of lipids with a common platform that is compatible with informatics requirements has been developed to deal with the massive amounts of data that will be generated by our lipid community. As an initial step in this development, we divide lipids into eight categories (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids, prenol lipids, saccharolipids, and polyketides) containing distinct classes and subclasses of molecules, devise a common manner of representing the chemical structures of individual lipids and their derivatives, and provide a 12 digit identifier for each unique lipid molecule. The lipid classification scheme is chemically based and driven by the distinct hydrophobic and hydrophilic elements that compose the lipid. This structured vocabulary will facilitate the systematization of lipid biology and enable the cataloging of lipids and their properties in a way that is compatible with other macromolecular databases.

A comprehensive classification system for lipids

AbstractLipids are produced, transported, and recognized by the concerted actions of numerous enzymes, binding proteins, and receptors. A comprehensive analysis of lipid molecules, “lipidomics,” in the context of genomics and proteomics is crucial to understanding cellular physiology and pathology; consequently, lipid biology has become a major research target of the postgenomic revolution and systems biology. To facilitate international communication about lipids, a comprehensive classification of lipids with a common platform that is compatible with informatics requirements has been developed to deal with the massive amounts of data that will be generated by our lipid community. As an initial step in this development, we divide lipids into eight categories (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids, prenol lipids, saccharolipids, and polyketides) containing distinct classes and subclasses of molecules, devise a common manner of representing the chemical structures of individual lipids and their derivatives, and provide a 12 digit identifier for each unique lipid molecule. The lipid classification scheme is chemically based and driven by the distinct hydrophobic and hydrophilic elements that compose the lipid. This structured vocabulary will facilitate the systematization of lipid biology and enable the cataloging of lipids and their properties in a way that is compatible with other macromolecular databases.[Reprinted with copyright permission from the Journal of Lipid Research. 2005. 46: 839–861.]