Pimelic Acid Research Articles

The Effect of the Surface Treatment on TiO2 Particles When Used as a Filler on Crystallization and Mechanical Properties of Polylactic Acid Composites. Case of Study: Silane Coupling Agents and Dicarboxylic Acids Were Used as Surface Modifiers

ABSTRACT This article analyzes the effect of the type of surface modification (using silane coupling agents and dicarboxylic acids) on titanium dioxide particles used as fillers in polylactic acid composites, which were exposed to a photodegradative process. The thermomechanical properties of the composites were analyzed; it was found that the silane coupling agent with Imidazole allowed the composites to have Young’s modulus values 60% lower than the composite without filler. On the other hand, the crystallization rate was 30% higher for composites with azelaic Acid attached to TiO2 particles than for composites without filler at a cooling rate of 5°C min−1. Once degraded composites containing azelaic acid were the least brittle, with a minor increment in Young’s Modulus compared to pure polylactic acid composites. When a mixture of modified titanium dioxide particles (with imidazole and either azelaic acid or pimelic acid) was used, there was a synergistic effect regarding photostability.

Effect of conformational landscape on the polymorphism and monomorphism of tizanidine cocrystallization outcomes

Molecular conformational diversity plays a crucial role in both polymorphic nucleation and cocrystal formation during the cocrystallization process. However, the relationship between molecular conformation and cocrystallization polymorphism is not well-explored. Herein, the impact of molecular conformational landscapes on cocrystallization outcomes was investigated using tizanidine (TZND) as model compound. Four coformers, namely maleic acid (MA), salicylic acid (SA), p-hydroxybenzoic acid (pHBA), and heptanedioic acid (HDA), were employed and five salt forms were developed for the first time. Compared with TZND, all five salts showed significantly improved water solubility and dissolution rate. The cocrystallization behavior of TZND varied with each coformer: MA exhibited solvent-dependent polymorphism, while SA, pHBA, and HDA showed solvent-independent monomorphism. Crystal structure and conformational analyses revealed the conformational variation of TZND across different cocrystallization outcomes. Molecular dynamics simulations and quantum chemical calculations demonstrated that the interplay between solvent effects and coformer interactions determines the dominant conformations of TZND. The cocrystallization nucleation process was also examined, and the molecular mechanism that explains both polymorphism and monomorphism in the cocrystallization of TZND was proposed.

Recognition of carboxylic acids and phosphonic acids using a 1,8-diphenylanthracene-based diguanidine in solution and solid states

A 1,8-diphenylanthracene-based diguanidine 1 has been designed and synthesized for the recognition of carboxylic acids and phosphonic acid derivatives. The diguanidine 1a forms 1:1 complexes with the dicarboxylic acids and the diphosphonic acid derivatives in a DMSO solution, and the formation of these complexes was confirmed by a DOSY NMR analysis. The binding mode towards the guanidyl group (Type I, Type II, two existing types of binding modes toward three nitrogen atoms) with a diphosphonic acid derivative was successfully demonstrated by the 2D NOESY analysis. The diguanidine 1a does not show any fluorescence in a DMSO solution, but after the addition of carboxylic acids, the formation of a stable complex or the formation of the protonated guanidinium (1a+2H+) were distinguishable by the observation of a light-blue fluorescence around 430 nm. These fluorescence observations can be determined the stability of the complexes of the diguanidine 1a with carboxylic acids. On the other hand, the DMSO solution of diguanidine 1a showed a light-blue fluorescence after the addition of phosphonic acids. Interestingly, diguanidine 1a recognized methylphosphonic acid 9a in the solid state by grinding and showed a green fluorescence, while the other phosphonic acids 9 and dicarboxylic acids (4d: pimelic acid, 4f: azelaic acid) showed a light-blue fluorescence in the solid state, and a selectivity was observed. These fluorescence characteristics of the diguanidine 1 are applicable for the detection of carboxylic acids and phosphonic acids, especially for methylphosphonic acid 9a in the solid state.

Microbiomics and metabolomics insights into the microbial regulation on the formation of flavor components in the traditional fermentation process of Chinese Hongqu aged vinegar

This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar, and explore the core functional microbes closely related to the formation of flavor components. Microbiome analysis demonstrated that Lactobacillus, Acetobacter, Bacillus, Enterobacter, Lactococcus, Leuconostoc and Weissella were the predominant bacterial genera, while Aspergillus piperis, Aspergillus oryzae, Monascus purpureus, Candida athensensis, C. xylopsoci, Penicillium ochrosalmoneum and Simplicillium aogashimaense were the predominant fungal species. Correlation analysis revealed that Acetobacter was positively correlated with the production of tetramethylpyrazine, acetoin and acetic acid, Lactococcus showed positive correlation with the production of 2-nonanone, 2-heptanone, ethyl caprylate, ethyl caprate, 1-hexanol, 1-octanol and 1-octen-3-ol, C. xylopsoci and C. rugosa were positively associated with the production of diethyl malonate, 2,3-butanediyl diacetate, acetoin, benzaldehyde and tetramethylpyrazine. Correspondingly, non-volatile metabolites were also detected through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. A variety of amino acids and functional dipeptides were identified during the traditional brewing of Hongqu aged vinegar. Correlation analysis revealed that Lactobacillus was significantly associated with DL-lactate, indolelactic acid, D-(+)-3-phenyllactic acid, pimelic acid, pregabalin and 3-aminobutanoic acid. This study is useful for understanding flavor formation mechanism and developing effective strategies for the suitable strains selection to improve the flavor quality of Hongqu aged vinegar.

Structural analysis and optoelectronic applications of 2-aminopyrimidine with pimelic acid crystal

This study investigates the reaction between 2-aminopyrimidine and pimelic acid, resulting in the formation of a novel crystal. The crystals were obtained through slow evaporation process. These crystals underwent PXRD testing to establish their crystalline properties. The values of the unit cell parameters are confirmed through SXRD analysis. The FTIR technique is applied to detect different functional groups present in the title crystals. The UV-Visible spectrum is recorded to find the band gap energy. From the photoluminescence spectrum the emission is observed at 353nm. The mechanical strength of the material against deformation is studied using Vickers micro hardness tester and the material is stated as soft material. The dielectric behaviour of the crystal is studied using LCRZ meter.

Improving oral delivery of ciprofloxacin through in situ spray drying and acid counterions

This study explores the application of a novel three-fluid nozzle spray drying technique in formulating in situ ciprofloxacin (CFX) salts for improved oral drug delivery. The used key materials in the study include CFX combined with four different counterions: succinic acid (SA), glutaric acid (GA), adipic acid (AA), and pimelic acid (PA), alongside hydroxypropyl methylcellulose (HPMC) as a matrix agent. The process utilized a three-fluid nozzle spray drying technique to produce CFX salts directly with these acids during the process, creating three types of formulations: pure salts (SALT), solutions of drug and polymer (SOL), and nanoprecipitates of drug within a polymer matrix (SUS). Powder X-ray Diffraction (PXRD) and Scanning Electron Microscopy (SEM) analyses revealed that the formulations predominantly exhibited an amorphous structure with varied particle shapes and sizes. The dissolution profiles of CFX salts show a marked burst release within the initial 5 min, with CFX-GA leading at nearly double the release rate of CFX-AA, after which all formulations rapidly achieve over 90 % dissolution and maintain a stable release up to 30 min. This pattern was attributed to the interactions between the drug salts and HPMC, resulting in a sustained release of CFX. In vivo experiments with rabbits revealed a higher plasma concentration of CFX for CGAH-sus compared to CGAH-sol, highlighting the enhanced bioavailability of the SUS formulation. The amorphous nature of CGAH-sus, with ionization confirmed through Raman spectroscopy, facilitated efficient drug release and absorption in the gastrointestinal tract. This study illustrates the effectiveness of the three-fluid nozzle spray drying method in producing salts with varied physical properties and dissolution profiles, holding potential for advanced oral drug delivery systems.

Water-mediated chelation dynamics of dicarboxylic acid functionalized TiO2 nanoparticles for β-nucleation enhancement in isotactic polypropylene composites

ABSTRACT Isotactic polypropylene (iPP) is the most prominent form of polypropylene, and β-phase is the most resistant to impact compared to the crystalline forms. However, β-phase is the least frequently obtained under conventional operating conditions. TiO2 nanoparticles were functionalized with dicarboxylic acids as nucleating agents to promote β-crystal formation in iPP. The effects of three dicarboxylic acids – glutaric, pimelic, and azelaic – were characterized on TiO2-modified surfaces. Additionally, the interactions between TiO2 and water molecules, crucial for the formation of chelating or bridging linkages, were analyzed using Fourier Transform Infrared spectroscopy. For pimelic and azelaic acids at the polymer processing temperature, the carboxyl group band disappeared, suggesting a transition of the acid-calcium union from a bridging to a chelating linkage due to the presence of water molecules. These molecules help maintain the stability of the chains during processing. X-ray diffraction (XRD) analysis confirmed a higher content of β-crystalline structures in iPP when modified with pimelic and azelaic acids. The research indicates that water molecules, desorbed during manufacturing, facilitate the chelating form, thereby enhancing β-nucleation and improving the surface properties of iPP composites. These β-nucleated PP composites represent a promising material solution for medical device applications, offering a compelling combination of enhanced properties and cost-effectiveness.

Synthesis of two coordination polymers for fluorescence sensing of dinotefuran and 2,4,6-Trinitrophenol

Two thermally and water stable zinc-based coordination polymers (CPs) [Zn2(bb)(AZA)2]n (1) and [Zn2(bb)(PA)2]n (2) (bb = 4,4′- bis (imidazolyl) biphenyl, H2AZA=Azelaic acid and H2PA=Heptanedioic acid) were synthesized by a hydrothermal method and were structurally characterized through X-ray single-crystal diffraction, X-ray powder diffraction, elemental analysis, thermogravimetric analysis, infrared spectroscopy, ultraviolet spectroscopy, and other tests. Both of CPs 1 and 2 have 2D layered networks. Notably, CP 1 behaves as a multi-responsive fluorescent sensor toward dinotefuran (DTF) and 2,4,6-trinitrophenol (TNP) with high sensitivity, selectivity, and stability based on high fluorescence quenching efficiency. The detection limits for dinotefuran (DTF) and 2,4,6-trinitrophenol (TNP) were determined to be 1.99 ppm and 3.19 ppm, respectively. Additionally, the color of the test paper remained unchanged under natural light. Furthermore, the possible sensing mechanisms have been discussed in detail, and are supported by PXRD analysis, UV–vis spectroscopy, and density functional theory (DFT).

Two new Zn(ii) coordination polymers incorporating 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline: Synthesis and structure

Abstract Based on phenanthroline derivate ligand and Zn(ii), two novel coordination polymers, namely [Zn(L)(hta)] n (1) and {[Zn2(L)2(dhb)2]·H2O} n (2) (L = 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, H2hta = heptanedioic acid, and H2dhb = 3,5-dinitro-2-hydroxybenzoic acid), have been synthesized under the hydrothermal condition. For 1, each hta anion bridges two Zn(ii) atoms in a tridentate mode to shape into a chain structure and through different π–π stacking interactions to form a three-dimensional supramolecular structure. The L ligand of 2 connects two neighbouring Zn(ii) atoms to give a 1D chain, which is further extended into the 2D supramolecular layer.

Construction of 0D guanine nanospheres/2D vermiculite nanosheets heterostructures in confined space towards humidity sensing and proton migrations

Heterostructures comprising zero–dimensional (0D) nanoparticles and two–dimensional (2D) nanosheets have garnered considerable interest for sensing applications. Guanine exhibits extraordinary functionality in terms of their abundant hydrogen bond donors/acceptors. In this study, the protonated amine matrix of guanine serves as augmented active sites, uniformly forming guanine nanoparticles (GN) between 2D vermiculite nanosheets (VMT) confined space. Through electrostatic interactions and cross–linking with heptanedioic acid (HA), a self–assembly heterostructure (GN/VMT–HA) was constructed, which may offer abundant transport channels for enhanced humidity sensing and proton migrations. The proton migrations of GN/VMT–HA increased from 0.585 mS/cm (11% RH) to 0.750 mS/cm (97%RH) at 25 °C. The humidity sensor based on GN/VMT–HA demonstrates excellent performance, including high sensitivity (30.20 Hz/%RH), small hysteresis (1.45% RH) and short response/recovery time (25 s/7 s). This study offers a simple green method for constructing 0D/2D nanocomposites for proton transfer and humidity–sensing applications.

The potential application of formulation with pimelic acid as eye drops for corneal collagen cross-linking

Background and aimKeratoconus is a slowly progressive and non-inflammatory disease of eye of unknown etiology characterized by significant structural degeneration, thinning and protrusion of cornea. Collagen cross linking using Riboflavin/ultraviolet A, paraformaldehyde and glutaraldehyde has been widely used to treat keratoconus, but these techniques have several clinical complications. This study aimed to develop a rapid, safer, less toxic and more effective method to increase the corneal stiffness hence treating keratoconus by using EDC/NHS coupling with pimelic acid (PA) as cross-linkers. MethodsThe viability of corneal epithelial and endothelial cells was examined using Alamar blue. The corneal collagen and tissue integrity were evaluated with Masson and hematoxylin and eosin stains respectively. Uniaxial tensile testing was conducted to determine the tissue stiffness. We further assessed the effective penetration depth of cross-linking by fluorescence dye and confocal microscopy. TUNEL assay was performed to detect the damaged DNA fragments in the presence of PA. ResultsThe effect of PA solution on corneal cross-linking showed a significant increase in corneal rigidity without affecting the epithelium integrity under neutralized pH condition, while DEC/NHS alone did not induce the mechanical property. The penetration depth showed consistent results with increased stiffness, which could be affected by the parameters including pH condition, coupling with or without PA. In addition, PA significantly decreased the percentage of TUNEL-positive cells compared to that of EDC/NHS only condition. The cytotoxic effect to endothelium was considered minimal and protected in the presence of PA. ConclusionsWe demonstrated PA as a potential alternative for cross-linking in the model of whole eye with intact epithelium and its protective role on endothelium. The administration of this chemical cross-linker stands as an extremely promising technique for the treatment of corneal keratoconus.

Minute-level synthesis of tunable carbon dots-based phosphorescence materials for information encryption and light-emitting diodes

The emergence of carbon dots has broadened the design and application of new room-temperature phosphorescence materials, but the mass production of long-lived color-tunable carbon dots-based phosphorescence materials (CDPMs) is still hindered by solvent dependence and time-consuming. In this work, a minute-level solid-phase synthesis strategy was proposed for the preparation of a series of CDPMs through pyrolyzing the mixture of boric acid and pimelic acid. By tuning the mass ratio of boric acid and pimelic acid, CDPMs with different room-temperature phosphorescence characterises can be obtained within 7 min. Preferably, the CDPMs-60 synthesized from the mass ratio of boric acid and pimelic acid of 60:1 exhibits a long afterglow length up to 10 s and has obvious phosphorescence chromatic aberrations following excitation at 254 and 365 nm, and phosphorescence lifetimes of CDPMs-60 in the blue and green band can reach 1030 ms and 555 ms, respectively. The CDPMs were further successfully applied for the information encryption and fabricating light emitting diodes based on their simple synthesis process, exceptional optical properties and low-toxicity. This study may provide a valuable reference for the facile synthesis and suitable commercial application of room temperature phosphorescence materials.

3D printing polypropylene composites reinforced with functionalized halloysite: Balance between stiffness and impact resistance

AbstractIn this work, a new nano‐reinforced polypropylene filament was produced and fabricated by 3D printing to create a nanocomposite with a good balance between stiffness and impact resistance properties. Nanocomposite filament with 0.5, 1.0, and 1.5 wt% of functionalized halloysite nanotubes was prepared. The chemical modification was carried out to obtain a reinforcement that could act as an improved β‐nucleating agent and characterized by infrared spectroscopy. The spectrum showed the appearance of two new bands at 1571 and 1410 cm−1, which could indicate an interaction between the pimelic acid molecules and the oxygenated surface of the halloysite nanotubes. Energy dispersive X‐ray spectroscopy analysis confirmed a good dispersion of the modified reinforcement along the surface of the nanocomposite filament. Wide‐angle X‐ray scattering and differential scanning calorimetry analyses showed the improvement of the β‐nucleating ability of the halloysite nanotubes through new chemically functionalized, obtaining percentages of β‐crystal of 80% for the nanocomposite reinforced with 0.5 wt%. The dynamic mechanical analysis showed that the 3D‐printed functionalized nanocomposites presented higher storage and loss modulus (an increase of 148% and 122%, respectively). Finally, the impact strength properties increased by 90%, 108%, and 21% for the functionalized nanocomposites with 0.5, 1.0, and 1.5 wt%, respectively.Highlights Chemical functionalization of a natural reinforcement as a ‐nucleating agent. 3D printing polypropylene nanocomposites with enhanced properties. Good balance between impact and stiffness properties of nanocomposites.

Dynamical mechanical and impact strength behavior of 3D‐printing testing specimens manufactured by fused filament fabrication of isotactic polypropylene/functionalized titania nanotubes nanocomposites: Influence of β‐crystal promoting

AbstractThermomechanical and impact properties of isotactic polypropylene nanocomposites reinforced with titania nanotubes (TiNTs) at weight distributions of 0.5, 1, and 1.5 wt% were investigated. The goal of this study was to create a novel iPP‐based nanocomposite filament fused filament fabrication (FFF) with improved thermo‐mechanical and impact properties to enable the creation of more customized geometries. First, TiNTs were chemically functionalized with pimelic acid (PA) to promote the β‐crystalline phase using Ca as anchoring. FTIR results revealed the presence of new bands at 1575 and 1413 cm−1, which were attributed to the anchoring of the PA molecule on the TiNT surface. TEM images of the TiNTs confirmed its tubular morphology before and after the functionalization, while the SEM/EDS analysis showed the good dispersion of carbon which can only come from the organic molecule employed in the functionalization. The nano‐reinforcements were incorporated by extrusion generating a filament to produce 3D‐printed specimens. The efficacy of the modified reinforcement as a β‐crystalline phase promoter was evaluated by wide‐angle x‐ray diffraction. The nanocomposite with 1% modified TiNTs showed the highest β‐crystal promotion with a kβ‐index of 89% while the nanocomposites reinforced with unmodified TiNTs reached only 15%. Furthermore, the thermomechanical and impact properties were characterized by dynamic mechanical analysis and Izod. In the first, the storage modulus (E′) was higher than the raw iPP for all nanocomposites, with an increase of about 148% and 107%, while the nanocomposite with a high percentage of β‐crystal showed an increase of 183% in the impact strength properties. A shift of Tg to higher temperatures was attributed to better interfacial interactions polymer/nano‐reinforcement because of the functionalization. The modified nano‐reinforcement was able to generate a 3D‐printed nanocomposite with higher stiffness and impact strength properties than the raw iPP.

Stilbenes-enriched peanut sprouts alleviated physical fatigue via regulating interactions of nutrients-microbiota-metabolites revealed by multi-omics analysis.

In this study, the antifatigue effect and mechanism of peanut sprouts were explored. BALB/c mice divided into three groups (control, dark and UV-C) were respectively supplemented with a normal diet, peanut sprouts (dark germination) added diet and stilbenes-enriched peanut sprouts (UV-C radiated germination) added diet. Results showed that swimming time and levels of blood glucose and antioxidant enzymes significantly increased, while contents of triglyceride and malondialdehyde notably decreased by peanut sprout supplementation. Besides, combined analysis of gut microbiota gene sequencing and targeted metabolomics of fecal metabolites revealed that peanut sprout supplementation up-regulated abundances and metabolic transformations of Catenibacillus, Odoribacter, Prevotellaceae-UCG-001 and Butyricicoccus while it down-regulated the abundance of Parabacteroides. Consequently, contents of sebacic acid, azelaic acid, suberic acid, heptanoic acid, pimelic acid, aminoadipic acid and mono-phenolics notably increased, which were markedly correlated with the antifatigue effect. Compared with the dark group, the swimming time, glutathione peroxidase activity, methylmalonylcarnitine content and abundances of Butyricicoccus, Catenibacillus and Lachnospiraceae NK4A136 were higher in the UV-C group, while opposite results were obtained for the levels of triglyceride, malondialdehyde, alpha-linolenic acid, gamma-linolenic acid, 10Z-heptadecenoic acid and palmitelaidic acid. Overall, peanut sprout supplementation could alleviate fatigue by modulating gut microbiota composition to promote fatty acid oxidation and lysine and stilbene catabolism to increase energy supply and regulate redox balance. UV-C-radiated peanut sprout supplementation could alleviate fatigue more effectively by up-regulating abundances of Butyricicoccus, Catenibacillus and Lachnospiraceae NK4A136 to promote long-chain fatty acid oxidation and catabolism of flavonoids and stilbenes efficiently.

Medium-chain dicarboxylic acids: chemistry, pharmacological properties, and applications in modern pharmaceutical and cosmetics industries.

Succinic (SUA), glutaric (GLA), pimelic (PA), suberic (SUBA), adipic (ADA), azelaic (AZA), and sebacic acids (SA) make up the majority of medium-chain dicarboxylic acids (MCDAs) with chain lengths of C4-C10, and are widely utilised in the chemical, food, textile, pesticide, pharmaceutical, and liquid crystal sectors. The MCDAs' two carboxyl groups provide them with an incredibly broad variety of applications. The focus of significant scientific research now is on the increasingly varied pharmacological effects of MCDAs. However, only a few studies have compared the biological characteristics of MCDAs in the contemporary pharmaceutical and cosmetic sectors and thoroughly examined the most recent research and marketing initiatives for MCDAs. This review's objective is to offer a thorough analysis of academic works on MCDAs, to assess the usefulness of these substances' chemical-pharmacological properties for use in the contemporary pharmaceutical and cosmetic industries, and to investigate the direction of their possible applications in these two disciplines. In addition, this review investigates how these compounds are metabolised in the human body.

Length effect of crosslinkers on the mechanical properties and dimensional stability of vitrimer elastomers with inhomogeneous networks

Inhomogeneous network construction is a useful strategy to solve the trade-off between mechanical strength and creep in vitrimer rubbers. But it is still lack of tools to tune the mechanical properties and network dynamics of this new system. In this paper, uneven distribution of functional groups was realized by sequential coordination polymerization of myrcene and isoprene and epoxidation. The following epoxidation and curing generated VMI-x samples with inhomogeneous network. Polyisoprene was used to prepare control samples called VPI-x with homogeneous network. Different lengths of dicarboxylic acid crosslinkers (SA = succinic acid, HA = heptanedioic acid, DA = decanedioic acid) were used to probe their effects on dynamic behaviors, mechanical properties and recyclability. Morphological test and nanomechanical mapping confirmed the inhomogeneous feature of VMI-x samples. For both inhomogeneous and homogeneous samples, SA and DA crosslinkers brought higher tensile strength and modulus, earlier SIC phenomenon and higher orientation percentage of amorphous molecular chains than those of HA, which are ascribed to extra permanent cross-linking existing in SA samples and transition entanglements existing in DA samples. However, the constrain effect of SA crosslinker is too strong in inhomogeneous network to sacrifice the extensibility, which is much smaller than those of HA and DA. SA and DA samples also present restricted segmental motion and superior creep resistant properties compared to HA samples according to the results of broadband dielectric spectroscopy and DMA test. Differently, at high temperature above 130 °C, the stress relaxation, topology freezing transition temperature (Tv) and recycling efficiency of strength are dominated by the crosslinker length monotonically, probably due to the disentanglement of DA crosslinkers. Compared to homogeneous network, inhomogeneous ones showed obvious enhanced mechanical properties, lower hysteresis, quicker segmental relaxation, lower creep and quicker network relaxation. This work demonstrates that crosslinker lengths could tune the vast aspects of vitrimer elastomers and is a non-negligible factor to determine their properties, especially for those with inhomogeneous networks.

Serum metabolomics detected by LDI-TOF-MS can be used to distinguish between diabetic patients with and without diabetic kidney disease.

Diabetic kidney disease (DKD) is an important cause of end-stage renal disease with changes in metabolic characteristics. The objective of this study was to study changes in serum metabolic characteristics in patients with DKD and to examine metabolite panels to distinguish DKD from diabetes with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). We recruited 40 type II diabetes mellitus (T2DM) patients with or without DKD from a single center for a cross-sectional study. Serum metabolic profiling was performed with MALDI-TOF-MS using a vertical silicon nanowire array. Differential metabolites between DKD and diabetes patients were selected, and their relevance to the clinical parameters of DKD was analyzed. We applied machine learning methods to the differential metabolite panels to distinguish DKD patients from diabetes patients. Twenty-four differential serum metabolites between DKD patients and diabetes patients were identified, which were mainly enriched in butyrate metabolism, TCA cycle, and alanine, aspartate, and glutamate metabolism. Among the metabolites, l-kynurenine was positively correlated with urinary microalbumin, urinary microalbumin/creatinine ratio (UACR), creatinine, and urea nitrogen content. l-Serine, pimelic acid, 5-methylfuran-2-carboxylic acid, 4-methylbenzaldehyde, and dihydrouracil were associated with the estimated glomerular filtration rate (eGFR). The panel of differential metabolites could be used to distinguish between DKD and diabetes patients with an AUC value reaching 0.9899-0.9949. Among the differential metabolites, l-kynurenine was related to the progression of DKD. The differential metabolites exhibited excellent performance at distinguishing between DKD and diabetes. This study provides a novel direction for metabolomics-based clinical detection of DKD.

Multiple hydrogen bonds network enabled sustainable and reproducible cellulose/liquid metal composite elastomer for clean energy collection and conversion

Fabrication of sustainable, mechanically robustness and reproducible metal polymer composite elastomer is desirable but remains a challenge. Herein, a multiple hydrogen bonds crosslinked metal polymer composite elastomer derived from cellulose, plant oil, nature rubber and liquid metal was prepared, which exhibited excellent mechanical elasticity, reproducible and photothermal conversion performance. To fabricate the proposed composite elastomer, the liquid metal (LM) droplets were dispersed within a mixture of amino cellulose (AC), pimelic acid modified epoxy soybean oil (ESOPA) and nature rubber matrix through high-frequency ultrasonication. The active groups of the AC and ESOPA were able to not only construct a multiple hydrogen bonds network to endow the composite elastomer with excellent mechanical strength (1.51 MPa) and stretchability (515.3%), but also stabilize the LM particles. And the broken and reconstruction of the multiple hydrogen bonds network allowed the composite elastomer to be healed quickly at room temperature with high self-healing efficiency of 97.28%. In addition, the LM in the waste composite elastomers could be effectively recycled through dissolution and extraction as well as obtained a regenerative NR/ESOPA/AC elastomer, and the recycling efficiency of LM was up to 85%. Most importantly, the NR/ESOPA/AC/LM composite elastomer possessed stable photothermal conversion property, and has been successfully applied to convert light energy to thermal, electric and kinetic energy to drive the Stirling motor and electric fan, which paved a promising strategy for clean energy collection and conversion.

Synthesis and characterization of graphene oxide functionalized with dicarboxylic acids

Graphene oxide (GO) has been reported as another kind of membrane material. Although the use of GO in thin film nanocomposites (TFNs) imbues advantages including antibacterial activity, major challenges to this approach include attrition of the GO sheets from the membrane surface and flux reduction where movement between GO sheets is impeded. This study examined the use of dicarboxylic acids for crosslinking GO sheets to prevent attrition and to control the interlayer spacing of GO sheets. GO prepared via the modified Hummers method, was crosslinked using three dicarboxylic acids of varying chain length: Glutaric (C5H8O4), Adipic (C6H10O14) and Pimelic (C7H12O4) acids. The FTIR spectrum revealed a wider and stronger absorption peak of GO near 3430 cm−1, which could be attributed to the stretching vibration peak of –OH. The peak at 1750 cm−1 revealed a stretching vibrations peak of C = O on the carboxyl group of graphite oxide. The esterification reaction largely occurred at the basal surface area and was shown via the disappearance of epoxy and hydroxyl groups being replaced by an amine group. The spatial XRD analysis showed that interlayer spacing between the GO sheets increased in the order: An increase in the molecular chain of the different crosslinker acids resulted in an increase in the interlayer spacing of the functionalized GO from 7.96Á −8.9À, with the diffraction peaks moving to lower angles. SEM images indicated different surface morphology, attributable to the different effects each dicarboxylic acid has on the initial GO formed.