1H Nuclear Magnetic Resonance Research Articles

Dihydroxyl-Cooperative 1,2,4-Triazole-Based Ionic Liquid for Robust Reversible CO2 Absorption.

The development of aqueous absorbents for CO2 capture is significantly important to reduce global industrial gas emissions through high regeneration efficiency and low energy consumption. Herein, we newly designed and prepared a dihydroxylated ionic liquid (IL) bis(2-hydroxyethyl)dimethylammonium 1,2,4-triazole ([N1,1,2OH,2OH][TZ]) for highly efficient CO2 absorption through anion-cation cooperative interactions. A superior capacity of 1.33 mol of CO2 per mol of IL and excellent reversibility have been achieved by the introduction of dihydroxy sites on the ammonium-based Tz IL. 1H and 13C nuclear magnetic resonance, Fourier transform infrared, and quantum chemical calculations demonstrate bihydroxyl-cooperative absorption of CO2 via hydrogen bond interaction between the cation and anion of the IL. The theory calculation shows that IL displays a superlow reactive absorption enthalpy, favorable to the reversible CO2 absorption, which can maintain an initial absorption capacity of 98.5% with the cycle numbers of 100, implying the facile regeneration and superlow energy consumption. Thus, the functionalized ILs toward group cooperative gas absorption and excellent reversibility may open a door to designing new materials for enhancing CO2 absorption and utilization.

Supramolecular Arrangement and Conformational and Dynamic Properties of Chiral Smectic Liquid Crystals Obtained through Nuclear Magnetic Resonance: A Brief Review

Ferroelectric and antiferroelectric smectic liquid crystalline (LC) phases are still at the center of investigations and interests for both their fundamental properties and variety of technological applications. This review aims to report the main contributions based on different nuclear magnetic resonance (NMR) techniques to the study of chiral liquid crystalline calamitic mesogens forming smectic phases, such as the SmA, the SmC* (ferroelectric), and the SmC*A (antiferroelectric) phases. 2H NMR and 13C NMR techniques and their combination were of help in clarifying the local orientational properties (i.e., the molecular and fragments’ main orientational order parameters) at the transition between the SmA and the SmC* phases, and in the particular case of de Vries liquid crystals, NMR studies gave important clues regarding the actual models describing the molecular arrangement in these two phases formed by de Vries LCs. Moreover, this review describes how the combination of 2H NMR relaxation times’ analysis, 1H NMR relaxometry, and 1H NMR diffusometry was successfully applied to the study of chiral smectogens forming the SmC* and SmC*A phases, with the determination of relevant parameters describing both rotational molecular and internal motions, collective dynamics, and translational self-diffusion motions. Several cases will be reported concerning NMR investigations of chiral ferroelectric and antiferroelectric phases, underlining the great potential of combined NMR approaches to the study of supramolecular, conformational, and dynamic properties of liquid crystals.

Green synthesis and characterization of trisubstituted imidazole derivatives by an ecofriendly and efficient heterogenous nanocatalyst based on magnetite nanoparticles coated modified nanocellulose

In the present work, a nanocellulose based magnetic nanocomposite [(pH-PDA-DANC)@Fe3O4NPs] was synthesized by an ecofriendly and a simple protocol and characterized by means of different techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) equipped with an Energy Dispersive X-ray (EDX) probe and the Value Stream Mapping (VSM). The theoretical study of [(pH-PDA-DANC)@Fe3O4NPs] was investigated using Density Functional Theory (DFT) at the DFT-D3/ B3LYP/LanL2DZ level of theory to explore the nature of the interactions between the (pH-PDA-DANC) ligand and magnetite nanoparticles. The results indicate that the Fe3O4 nanoparticles form covalent bonds with the N-ring of the ligand. Then, it was used as a catalyst in the green and efficient procedure for one-pot multicomponent syntheses of imidazole derivatives by the condensation of benzil or 9.10-phenanthrenequinone, benzaldehyde derivatives and ammonium acetate. The catalytic reaction provided the synthesis of above imidazole derivatives with high reaction efficiency (80 %-98.1 %) in a short reaction time (3 h) and in presence of a minimum amount of ethanol. The identification and structure of imidazole derivatives was determined analyzing the 1H NMR (Nuclear Magnetic Resonance) and FTIR spectra. This procedure has several advantages compared to the conventional method such as the high yields, short reaction times, easy separation of the nanocatayst from the reaction mixture by using a magnet, and the reusability of the catalyst.

Evaluation of Zeolite Composites by IR and NMR Spectroscopy.

In this study, we assessed the quantity, strength, and acidity of zeolite composites comprising Silicalite-1 grown on ZSM-5 crystals using a combination of infrared (IR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. The composites were created through the direct growth of Silicalite-1 crystals on ZSM-5 (P_ZSM-5), either with or without the organic structure-directing agent (OSDA) introduced into the ZSM-5 channels (samples: H_ZSM-5_Sil1 and TPA_ZSM-5_Sil1). The results revealed that Silicalite-1 grew differently when the ZSM-5 core was in the H+ form (empty pores) compared to when the OSDA was still present in the sample. This distinction was evident in the textural properties, with a decrease in the micropore surface area and an increase in the external surface area in the H_ZSM-5_Sil1 compared to the parent sample. The TPA_ZSM-5_Sil1 composite exhibited characteristics similar to the parent zeolite. These findings were further supported by 29Si NMR, which revealed a comparable local order for the parent (P_ZSM-5) and TPA_ZSM-5_Sil1 samples, along with a broadening of the Q4 peak for the H_ZSM-5_Sil1 composite. Additionally, the acid sites were preserved in the TPA_ZSM-5_Sil1 composite, while in the H+-form core, the concentration of Brønsted acid sites significantly decreased. This reduction in isolated Brønsted acid sites was further corroborated by 1H NMR.

Benzimidazole-acrylonitrile hybrid derivatives act as potent urease inhibitors with possible fungicidal activity.

Aim: A series of benzimidazole-acrylonitrile derivatives TM1-TM53 were designed with urease inhibition approach.Materials & methods: TM1-TM53 were synthesized and characterized (1H Nuclear Magnetic Resonance (NMR), 13C NMR, Mass Spectroscopy (MS) and IR) and subjected to urease inhibition assay using commercial assay kit. A molecular docking study was also performed using Autodock tool software.Results: Except six compounds, target molecules exhibited a higher urease inhibition effect (IC50: 1.22-28.45μM) than hydroxyurea (IC50: 100μM). kinetic study on TM11, clarified its mode of action as a mixed inhibitor. A molecular docking study on TM6, TM11 and TM21, was performed and the results showed the main residues inside the active site of the enzyme. All TM1-TM53 were also studied in silico using molecular docking techniques to evaluate their potential to inhibit succinate dehydrogenase in comparison to fluxapyroxad as standard. Docking study revealed the high potential of TM1-TM53 as a fungicides.Conclusion: Obtained results exhibited the high activity of benzimidazole-acrylonitrile derivatives as urease inhibitors and their possible potential as fungicide agents. So, it will be beneficial to do more bioactivity investigation on this family of compounds.

ELSA-PSYCHE: An Improved Method for Protecting Pure Shift Spectra from Artifacts.

Numerous 1H-1H J couplings contribute to complex multiplets in 1H nuclear magnetic resonance spectroscopy, leading to an ambiguous spectral assignment, particularly for strongly coupled protons. Although the PSYCHE approach has proven to be effective in simplifying complex spectra by collapsing J couplings, the PSYCHE pure shift spectrum of strongly coupled protons always suffers from sideband artifacts and baseline oscillations, which impede spectral identification. Herein, we introduce a novel universal technique designed to separate artifacts from the desired absorption-mode pure shift signals. This new study will significantly benefit the development of molecular structure elucidations and composition analysis in the fields of chemistry, biochemistry, and metabonomics.

Synthesis, recognition properties and drug release behavior of diltiazem‐imprinted chitosan‐based biomaterials

AbstractIn this study, we prepared diltiazem (DTZ)‐imprinted biomaterials for TDDS using chitosan, PVA, plasticizers, and sulfosuccinic acid. DTZ and the prepared biomaterials were characterized using field emission scanning electron microscopy, Fourier transform infrared, and 1H nuclear magnetic resonance. DTZ recognition properties were confirmed by the binding isotherm, Scatchard plot analysis, the adsorption of materials with structures similar to DTZ, selectivity factor (α), and the imprinting‐induced promotion of binding (IPB). Results revealed that adsorbed amount (Q) of DTZ‐imprinted biomaterials was 1.63–2.53 times higher than that of non‐imprinted biomaterials. In addition, it could be verified that DTZ‐imprinted biomaterials have a binding site for DTZ according to Scatchard plot analysis. Furthermore, the results of α and IPB indicated that the recognition capacity of the prepared DTZ‐imprinted biomaterials is superior to that non‐imprinted biomaterials. DTZ release properties were evaluated under various pH buffers and artificial skin. Results indicated that the DTZ release in buffers at low pH was faster than that in buffers at high pH. The DTZ release using artificial skin was continuous over 20 days. Furthermore, the DTZ release profile in the buffer followed the pseudo‐Fickian diffusion mechanism, whereas the profile in the artificial skin test followed a non‐Fickian diffusion mechanism.

Extraction of rare earth ions using thermomorphic ionic liquid: In situ spatial and temporal distribution combined with thermodynamic description

Homogeneous Liquid–Liquid Extraction (HLLE) provides a valuable opportunity for recycling Rare Earth Elements (REE) by circumventing the liquid–liquid interface and avoiding the problems linked to the high viscosity of ionic liquids (IL). For optimizing these processes with the ultimate goal of implementing them at the industrial scale, it is crucial to understand the mechanisms at play at various scales. In this study, we focused on the extraction of two REE elements, La(III) and Ce(III) with an HLLE system composed of the IL [Chol][TFSI], water and betaine as the extractant. We first established the phase diagram of [Chol][TFSI]/betaine/water using 1H nuclear magnetic resonance (NMR) spectroscopy. We then determined the efficiency E and distribution ratio D of the HLLE for different betaine concentrations. HLLE was modeled thermodynamically to access the most likely number of betaine molecules involved in the extraction process, which appears to be 2. Finally, we monitored in situ the extraction using X-ray Absorption Spectroscopy (XAS) at the K-edge of both lanthanum and cerium. It allowed us on one hand, to get some insight into the local environment around the REE, and on the other hand to measure the local concentration of REE at each position within the extraction system. In this latter process, we could evidence an accumulation of REE accumulates close to the liquid–liquid interface, a feature that was suggested by some recent simulations.

Moisture sorption behaviour, microstructural changes and macroscopic deformation of hardened cement pastes during the first three drying–resaturation cycles

Moisture sorption and macroscopic deformation of hardened cement pastes (hcps) were studied in the first three drying–resaturation (D–R) cycles using low–field 1H nuclear magnetic resonance relaxometry. Four types of water (interlayer, gel, interhydrate and capillary) were detected in the hcps. In principle, they were sequentially removed from larger to smaller pores during drying with decreasing relative humidity (RH), resulting in shrinkage of the hcps. Unexpected increases in gel and interlayer water contents as well as greater shrinkage during drying from 100 % to 69 % RH were observed, which is believed to originate from the re–arrangement of C–S–H structure. Because of the C–S–H re–arrangement, irreversible shrinkage was detected during D–R cycles. The drying and irreversible shrinkage in each cycle diminished with the D–R number. A lower water–to–cement ratio and higher curing temperature for hcps are beneficial for reducing drying and irreversible shrinkage.

Enantioselective Synthesis, Crystal Structures, and Stereoisomerism of Substituted o,m,o,p-Tetraphenylenes.

We have achieved the enantioselective synthesis of highly strained, substituted o,m,o,p-tetraphenylenes (≤98% ee) via the cationic Rh(I)/(R)-H8-BINAP complex-catalyzed chemo-, regio-, and enantioselective intermolecular cross-[2+2+2] cycloaddition of teraryl diynes with dimethyl acetylenedicarboxylate. X-ray crystallographic analyses demonstrate the highly bent structures of the para-substituted benzene moieties, and density functional theory calculations reveal the large local strain of the paraphenylene unit. 1H nuclear magnetic resonance analyses and theoretical calculations elucidate the stereoisomerism, indicating that the nonrotatable ortho-disubstituted biphenyl structure results in cis and trans isomers.

Synthesis, Hemolytic Activity, and In Silico Studies of New Bile Acid Dimers Connected with a 1,2,3-Triazole Ring.

The synthesis of bile acid conjugates plays a significant role in pharmacology and organic chemistry. These complex compounds are widely studied due to their potential therapeutic applications (e.g., drug carriers or antibacterial agents) and their impact on interactions with biological target systems. It is important to determine the biological activity of the obtained conjugates with potential pharmacological applications. The research aimed to synthesize acyl conjugates of bile acids, determine the influence of acyl groups on potential antibacterial activity and evaluate the impact of conjugation on hemolytic activity. New acetyl bile acid acetyl dimers were synthesized using the "Click Chemistry" reaction, aiming to investigate their hemolytic and antibacterial activity. The structures of all compounds were confirmed through spectral analysis techniques, including 1H and 13C nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and electrospray ionization-mass spectrometry (ESI-MS). The PM5 semiempirical method was also used to estimate the heat of formation of individual conjugates, and the prediction of activity spectra for substances (PASS) technique was used to determine the pharmacokinetic potential of compounds. Docking studies indicate that obtained conjugates have the potential ability to inhibit the biosynthesis of Lipid II and block DNA gyrase. These compounds can therefore be treated as potential candidates for antibacterial compounds. Research findings suggest that conjugating bile acids and their derivatives through 1,2,3-triazole ring, results in final products with reduced hemolytic activity.

The Persistence of Hydrogen Bonds in Pyrimidinones: From Solution to Crystal.

Pyrimidinone scaffolds are present in a wide array of molecules with synthetic and pharmacological utility. The inherent properties of these compounds may be attributed to intermolecular interactions analogous to the interactions that molecules tend to establish with active sites. Pyrimidinones and their fused derivatives have garnered significant interest due to their structural features, which resemble nitrogenous bases, the foundational building blocks of DNA and RNA. Similarly, pyrimidinones are predisposed to forming N-H···O hydrogen bonds akin to nitrogenous bases. Given this context, this study explored the supramolecular features and the predisposition to form hydrogen bonds in a series of 18 substituted 4-(trihalomethyl)-2(1H)-pyrimidinones. The formation of hydrogen bonds was observed in solution via nuclear magnetic resonance (NMR) spectroscopy experiments, and subsequently confirmed in the crystalline solid state. Hence, the 18 compounds were crystallized through crystallization assays by slow solvent evaporation, followed by single-crystal X-ray diffraction (SC-XRD). The supramolecular cluster demarcation was employed to evaluate all intermolecular interactions, and all crystalline structures exhibited robust hydrogen bonds, with an average energy of approximately -21.64 kcal mol-1 (∼19% of the total stabilization energy of the supramolecular clusters), irrespective of the substituents at positions 4, 5, or 6 of the pyrimidinone core. To elucidate the nature of these hydrogen bonds, an analysis based on the quantum theory of atoms in molecules (QTAIM) revealed that the predominant intermolecular interactions are N-H···O (average of -16.55 kcal mol-1) and C-H···O (average of -6.48 kcal mol-1). Through proposing crystallization mechanisms based on molecular stabilization energy data and contact areas between molecules and employing the supramolecular cluster and retrocrystallization concepts, it was determined that altering the halogen (F/Cl) at position 4 of the pyrimidinone nucleus modifies the crystallization mechanism pathway. Notably, the hydrogen bonds present in the initial proposed steps were confirmed by 1H NMR experiments using concentration-dependent techniques.

Breaking New Ground towards Innovative Synthesis of Palladacycles: The Electrochemical Synthesis of a Tetranuclear Thiosemicarbazone-[C,N,S] Palladium(II) Complex.

The electrochemical oxidation of anodic metals (M = nickel and palladium) in an acetonitrile solution of the thiosemicarbazone ligands (E)-2-(1-(4-methoxyphenyl)ethylidene)-N-methylhydrazine-1-carbothioamide (a), (E)-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (b), and (E)-N-phenyl-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (c) yielded the homoleptic complexes [ML2], 1a, 1b, 1c, and 2c and [M4L4], 2a as air-stable solids. The crystal structures for 1a, 1b, 1c, and 2c show the ligands in a transoid disposition with the [S,S] and [N,N] donor atom pairs occupying cis positions on the nearly square planar coordination plane of the metal. The structure for 2a of S4 symmetry comprises a tetranuclear palladacycle where the metalated ligands are arranged around a central Pd4S4 environment: a crown ring with alternating palladium and sulfur atoms. The latter complex is the first example of an electrochemical preparation of a cyclometalated palladium compound, marking a milestone in the chemistry of such species. The compounds have been fully characterized by elemental microanalysis, mass spectrometry, infrared (IR), and 1H nuclear magnetic resonance (NMR) spectra.

Microstructure analysis of cement-biochar composites

The use of biochar as a concrete constituent has been proposed to reduce the massive carbon footprint of concrete. Due to the low density and complex porosity of biochar, microstructural analysis of Portland cement-biochar composites is challenging. This causes challenges to the improvement of the micro-scale understanding of biochar composite behavior. This work advances the microstructural understanding of Portland cement composites with 0, 5, and 25 volume percent (vol%) of cement replaced with wood biochar by applying common characterization techniques of mercury intrusion porosimetry (MIP), gas sorption, scanning electron microscopy, and isothermal heat flow calorimetry (HFC) in conjunction with 1H nuclear magnetic resonance (NMR) and micro-X-ray computed tomography (XCT) analysis techniques. The combination of these techniques allows a multi-scale investigation of the effect of biochar on the microstructure of cement paste. NMR and XCT techniques allow the observation and quantification of the pore space. HFC and MIP confirmed that biochar absorbs moisture and reduces the effective water-cement ratio. Gas sorption, MIP, and NMR shows that 5 vol% replacement does not significantly affect the gel and capillary pore structures. Results from XCT (supported by MIP and NMR) show that biochar can reduce the formation of larger pores. Importantly, XCT results suggest that biochar can act as a flaw in the microstructure which could explain reductions in the mechanical properties. Overall, the mechanical properties already analyzed in the literature are consistent with the microstructural changes observed, and these results highlight the need to carefully tailor the volume fraction of biochar to control its effect on the paste microstructure.

Glycyrrhetinic acid-modified redox-sensitive polymeric mixed micelles for tumor-specific intracellular delivery of cantharidin.

Cantharidin (CTD) has been widely used to treat hepatocellular carcinoma (HCC) in clinical practice. However, the current CTD preparations may induce hepatic and renal damage due to their non-specific distribution. Therefore, redox-sensitive polymer Pluronic F127-disulfide bond-poly(d,l-lactide) (F127-SS-PDLA) and active targeting polymer F127-glycyrrhetinic acid (F127-GA) were synthesized to prepare mixed micelles (GA/F127-SS-PDLA/CTD) for effective delivery of CTD. Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy were used to verify the successful synthesis of F127-SS-PDLA and F127-GA. During the preparation, this study was the first to screen the density of GA by cellular uptake assay. The results indicated that mixed micelles with 10% and 15% F127-GA (weight fraction) exhibited superior cellular uptake in comparison to micelles with 5% and 20% F127-GA. GA/F127-SS-PDLA/CTD micelles prepared by thin film hydration method demonstrated excellent drug loading capacity for CTD (16.12 ± 0.11%). The particle size and zeta potential of GA/F127-SS-PDLA/CTD micelles were 85.17 ± 1.24 nm and -11.71 ± 0.86 mV, respectively. Hemolysis and stability assay showed that the mixed micelles had good blood compatibility and could remain stable for 30 days at 4 °C. The redox-sensitivity of GA/F127-SS-PDLA/CTD micelles in vitro was verified under reducing conditions through dynamic light scattering (DLS) and an in vitro drug release experiment, which showed obvious particle size variation and rapid drug release ability. In cellular experiments, GA/F127-SS-PDLA/CTD micelles could induce superior cytotoxicity, apoptosis and intracellular reactive oxygen species (ROS) levels compared with free CTD, non-sensitive F127-PDLA/CTD micelles and redox-sensitive F127-SS-PDLA/CTD micelles. The cellular uptake ability of nile red-labeled GA/F127-SS-PDLA micelles, which was evaluated via fluorescent microscope and flow cytometry, indicated that the modification of GA significantly increased micelle uptake in HepG-2 cells. Consequently, GA/F127-SS-PDLA/CTD micelles could be considered as a satisfactory drug administration strategy in the treatment of HCC.

Effective treatment of traumatic brain injury by injection of a selenium-containing ointment

Traumatic brain injury (TBI) is an incurable and overwhelming disease accompanied with serve disability and huge financial burden, where the overproduced reactive oxygen species (ROS) can exacerbate the secondary injury, leading to massive apoptosis of neurons. In this study, β-cyclodextrin (CD)-capped hyperbranched polymers containing selenium element (HSE-CD) were crosslinked with CD-modified hyaluronic acid (HA-CD) and amantadine-modified hyaluronic acid (HA-AD) to obtain a ROS-responsive ointment (R-O). The structures of synthesized polymers were characterized with 1H nuclear magnetic resonance, and the properties of ointment were investigated with rheology and antioxidation. Compared to non-ROS-responsive ointment (N-O), the R-O ointment had stronger efficiency in decreasing the ROS level in BV2 cells in vitro. In a controlled rat cortical impact (CCI) model, the R-O ointment could relieve the DNA damage and decrease apoptosis in injured area via reducing the ROS level. Besides, after the R-O treatment, the rats showed significantly less activated astrocytes and microglia, a lower level of pro-inflammatory cytokines and a higher ratio of M2/M1 macrophage and microglia. Moreover, compared to the TBI group the R-O ointment promoted the doublecortin (DCX) expression and tissue structure integrity around the cavity, and promoted the recovery of nerve function post TBI. Statement of significanceTraumatic brain injury (TBI) is an incurable and overwhelming disease, leading to severe disability and huge social burden, where reactive oxygen species (ROS) are considered as one of the most significant factors in the secondary injury of TBI. A ROS responsive supramolecular ointment containing di-selenide bonds was injected in rats with controlled cortical impact. It relieved the DNA damage and decreased apoptosis in the injured area via reducing the ROS levels, downregulated neuroinflammation, and improved neurological recovery of TBI in vivo. This designed self-adaptive biomaterial effectively regulated the pathological microenvironment in injured tissue, and achieved better therapeutic effect.

Three birds with one stone: Sewage sludge deep-drying in 1 hour using secondary aluminum ash to fabricate bricks

Due to the high moisture, strong hydrophilicity, and hard compressibility of sewage sludge (SS), it is difficult to realize the high-efficiency drying. Herein, a novel SS drying technology was developed to quickly and deeply reduce the moisture of SS from 75.6% to 38.5% in 1 h. During the process, secondary aluminum ash (SAA), a solid waste, was added to SS and acted as skeletons to form plenty of channels. Subsequently, NaOH was added and reacted with SAA to produce a lot of heat, resulting in a rapid temperature rise of the system from 20 to 105°C in 60 s. The heat could effectively remove water from these channels, which could be proved by the T1-T2 maps of in-site Low-Field 1H nuclear magnetic resonance. In addition, the extracellular polymeric substances were decomposed by SAA/NaOH successfully, and thus the SS became hydrophobic, favoring the drying. Finally, the dried SS could be used to fabricate unburned bricks. Thus, this work provides a promising method to realize the rapid SS deep drying and high-efficiency utilization of SAA and dried SS.

Engineering fully quaternized (Dimethylamino)ethyl methacrylate-based photoresins for 3D printing of biodegradable antimicrobial polymers

Nowadays, medical devices or implants are widely used in the medical field to treat different diseases. However, bacterial infections are one of the significant problems associated with medical devices and are recognized as a concern in healthcare worldwide. Addressing this problem has driven the exploration of new materials with potent antibacterial properties. In this regard, quaternary ammonium compounds (QACs), which are organic salts with an alkane chain and a charged part of quaternary ammonium groups, came up with a potent antibacterial activity. Herein, we report for the first-time dimethylamino ethyl methacrylate (DMAEM) derived quaternary ammonium monomer and crosslinker to prepare photoresins for DLP (Digital light processing) 3D printing. The structure of the synthesized monomer and crosslinker was confirmed via FTIR (Fourrier Transform Infrared) and 1H NMR (Hydrogen Nuclear Magnetic Resonance) while the physicochemical properties of the 3D printed polymer were investigated using TGA (Thermogravimetric Analysis), DSC (Differential Scanning Calorimeter) and UTM (Universal testing machine). By optimizing the printing conditions and monomer to crosslinker ratio, we can print high-resolution 3D-printed objects. Additionally, in vitro biodegradation, cytocompatibility, and hemocompatibility tests revealed that the printed polymers are biodegradable, cytocompatible, and hemocompatible in nature. More importantly, the printed polymers exhibited strong antibacterial activity against both gram-negative and gram-positive bacteria, suggesting their potential utility in personalized antibacterial medical devices.

Metabolic Choreography of Energy Substrates During DCD Heart Perfusion.

The number of patients waiting for heart transplant far exceeds the number of hearts available. Donation after circulatory death (DCD) combined with machine perfusion can increase the number of transplantable hearts by as much as 48%. Emerging studies also suggest machine perfusion could enable allograft "reconditioning" to optimize outcomes. However, a detailed understanding of the energetic substrates and metabolic changes during perfusion is lacking. Metabolites were analyzed using 1-dimensional 1H and 2-dimensional 13C-1H heteronuclear spectrum quantum correlation nuclear magnetic resonance spectroscopy on serial perfusate samples (N = 98) from 32 DCD hearts that were successfully transplanted. Wilcoxon signed-rank and Kruskal-Wallis tests were used to test for significant differences in metabolite resonances during perfusion and network analysis was used to uncover altered metabolic pathways. Metabolite differences were observed comparing baseline perfusate to samples from hearts at time points 1-2, 3-4, and 5-6 h of perfusion and all pairwise combinations. Among the most significant changes observed were a steady decrease in fatty acids and succinate and an increase in amino acids, especially alanine, glutamine, and glycine. This core set of metabolites was also altered in a DCD porcine model perfused with a nonblood-based perfusate. Temporal metabolic changes were identified during ex vivo perfusion of DCD hearts. Fatty acids, which are normally the predominant myocardial energy source, are rapidly depleted, while amino acids such as alanine, glutamine, and glycine increase. We also noted depletion of ketone, β-hydroxybutyric acid, which is known to have cardioprotective properties. Collectively, these results suggest a shift in energy substrates and provide a basis to design optimal preservation techniques during perfusion.

1H Nuclear Magnetic Resonance Spectroscopy Reveals Changes in Metabolic Phenotype Associated with Disease Stage in Patients with Chronic Venous Disease

1H Nuclear Magnetic Resonance Spectroscopy Reveals Changes in Metabolic Phenotype Associated with Disease Stage in Patients with Chronic Venous Disease