Glutaric Acid Research Articles

Petal-by-petal tree-blossoming shaped bimetallic MOF-based material over SBA-15: Diverse designability, synergistic catalysis, and thermodynamics/kinetic analysis

Transition metal-based bimetallic MOF (CoMo-ZIF) with two different metal ions (Co/Mo) possess specific synergistic catalytic effect in olefins oxidation, but poor diffusion efficiency and less active areas limit its application. Herein, a novel CoMo-ZIF-based nanocomposite is fabricated via an in-situ solvothermal approach to break down active area or diffusion efficiency barrier of CoMo-ZIF via employing SBA-15 as the matrix and nanosacle polyoxometalate (POM) as external active species. Characterizations reveal that pristine rose-type CoMo-ZIF (∼350 nm diameter) alters to rambutan-like hollow sphere and eventually self-assembles into hierarchical petal-by-petal nanoflakes (ca. 20∼50 nm in thickness) after SBA-15 and POM introduction, respectively. POM@CoMo-ZIF@SBA-15 with super large pore size (10.44 nm) and increased active (Co2+ + Co3+)/satellite (1.92) exhibits excellent catalytic activity in cyclopentene (CPE) oxidation to glutaric acid (GAC) with 57.1 % CCPE, 61.6 % SGAC, and good reusability with 54.3∼57.1 % CCPE and 58.4∼63.2 % SGAC during 6 cycles. What's more, thermodynamic analysis indicates that CPE oxidation to GAC is a spontaneous reaction at 273.15∼373.15 K, and kinetic study shows that the key to develop CPE to GAC is to reduce activation energies of cyclopentene oxide ring-opening to 1,2-cyclopentanediol (73.8298 kJ⋅mol−1) and glutaradehyde (118.4571 kJ⋅mol−1). This study not only pioneers a promising strategy for oriented design of MOF-based materials, but also serves as a valuable reference for the computation of various chemical reactions.

Use of Organic Acids as Additives for Plasma Electrolytic Oxidation (PEO) of Titanium

The present study investigates the influence of organic acids, added to the electrolytic solution, on the structure, morphology, and corrosion behaviour of plasma electrolytic oxidation (PEO) coatings produced on titanium grade 2. Particular attention is paid to the role of functional groups in the modification of the oxide’s properties. For this reason, all three selected acids, namely glutaric, glutamic, and tartaric acid, display two carboxylic groups, thus they interact with the substrate material mainly through –COO− adsorption. However, glutamic acid also has an amine group, while tartaric acid has two hydroxyl groups. The presence of such additional functional groups is found to impact the formation of the PEO coatings. According to scanning electron microscopy (SEM) analyses, the number of defects and their dimension increase with an increasing number of active groups present in the organic molecules. Then, when glutaric acid with only two carboxyl groups, is employed as an additive, smaller pores are produced. The dimension of defects increases when glutamic and tartaric acid are used. X-ray diffraction (XRD) testing demonstrates that rutile and anatase are present in all the coatings and that when using tartaric acid, a relatively high level of amorphism is reached. The electrochemical and corrosion behaviours are evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) performed in a heated sulphuric acid solution. It is found that all types of coatings provide protection against corrosion, with oxides produced using glutamic acid showing the lowest corrosion current density (0.58 mA·m−2) and low corrosion rate (1.02 μm·y−1).

Liquid phase oxidation of cyclopentanone over metal-free carbon catalysts

Oxidation of cyclopentanone (CPO) was studied over metal-free carbon catalysts in solvent-free conditions. Norit SX plus (900 m2 g−1) and Vulcan XC72 (240 m2 g−1) were used as pristine materials. Catalysts were prepared by activation in nitrogen and by treatment with urea, calcined in nitrogen at 500 °C and 950 °C. SEM, EDX, XPS, X-ray powder diffraction, nitrogen adsorption–desorption isotherms, acid–base titration, FTIR and Raman techniques were used for characterization. Catalytic tests carried out at 0.45 MPa and 80–110 °C enabled to find the best results: 30% selectivity to glutaric acid (GA) and 3% to succinic acid at 25% conversion of CPO, over Vulcan type catalysts. A low activity, selectivity and strong deactivation of Norit type catalysts can be ascribed to a higher specific surface in a disordered arrangement providing a high concentration of unselective catalytic sites. A higher extent of side reactions can yield in higher molar mass products, which stick on the surface and block catalytic sites. Optimum amount of accessible planar domains, represented by graphene and/or graphitic plates with some disorders present in Vulcan type catalysts classified them superior to Norit catalysts. A redox reaction scheme of oxidation of CPO to GA is also proposed.Graphical abstract

Rhinosinusitis in children with acute respiratory infection: quality of life and features of drug therapy

BACKGROUND: The relevance of the study is due to limited information on the impact of various forms of rhinosinusitis that have arisen against the background of acute respiratory infection on the quality of life of children and effective treatment methods. AIM: To conduct a clinical assessment of the effect on the recovery time and quality of life in children with acute rhinosinusitis and exacerbation of polypous rhinosinusitis that occurred against the background of a respiratory infection, including antiviral drugs in complex treatment in the early stages. MATERIALS AND METHODS: A simple controlled randomized comparative clinical trial was conducted, involving 74 children aged 15 to 18 years. The clinical efficacy and safety of the use of antiviral drugs in complex therapy, which are neuraminidase inhibitors on the 5th, 7th and 10th days of treatment, were evaluated in comparison with groups receiving pentanedioic acid imidazolylethanamide. The inclusion criterion was acute rhinosinusitis and exacerbation of chronic polypous rhinosinusitis against the background of acute respiratory infection. To establish the diagnosis, an examination of ENT organs, computed tomography of the nose and paranasal sinuses were performed, patients subjectively assessed clinical complaints and quality of life in the Russian version of the standard form of the SF-36 questionnaire. RESULTS: Positive dynamics was noted in the early stages in the 2nd subgroup of the 1st group who took neuraminidase inhibitors in addition to complex therapy. Manifested by a decrease in the average score for VAS to 80.0%, difficulty in nasal breathing to 1.7 points on the 10th day of treatment, relative to those taking imidazolylethanamide pentanedioic acid, where there was a decrease in the average score for VAS by 22.4%, difficulty in nasal breathing to 2.54 points. A similar pattern was observed with nasal congestion, rhinorrhea, and quality of life indicators according to the SF-36 questionnaires. CONCLUSION: Improvement of clinical symptoms and quality of life indicators at an earlier date in children with polypous rhinosinusitis and acute rhinosinusitis against the background of a previous respiratory infection with the inclusion of neuraminidase inhibitors in complex therapy confirmed higher efficacy.

Technical note: Characterization of a single-beam gradient force aerosol optical tweezer for droplet trapping, phase transition monitoring, and morphology studies

Abstract. Single particle analysis is essential for a better understanding of the particle transformation process and to predict its environmental impact. In this study, we developed an aerosol optical tweezer (AOT) Raman spectroscopy system to investigate the phase state and morphology of suspended aerosol droplets in real time. The system comprises four modules: optical trapping, reaction, illumination and imaging, and detection. The optical trapping module utilizes a 532 nm laser and a 100 × oil immersion objective to stably trap aerosol droplets within 30 s. The reaction module allows us to adjust relative humidity (RH) and introduce reaction gases into the droplet levitation chamber, facilitating experiments to study liquid–liquid phase transitions. The illumination and imaging module employs a high-speed camera to monitor the trapped droplets, while the detector module records Raman scattering light. We trapped sodium chloride (NaCl) and 3-methyl glutaric acid (3-MGA) mixed droplets to examine RH-dependent morphology changes. Liquid–liquid phase separation (LLPS) occurred when RH was decreased. Additionally, we introduced ozone and limonene/pinene to generate secondary organic aerosol (SOA) particles in situ, which collided with the trapped droplet and dissolved in it. To determine the trapped droplet's characteristics, we utilized an open-source program based on Mie theory to retrieve diameter and refractive index from the observed whispering gallery modes (WGMs) in Raman spectra. It is found that mixed droplets formed core–shell morphology when RH was decreased, and the RH dependence of the droplets' phase transitions generated by different SOA precursors varied. Our AOT system serves as an essential experimental platform for in situ assessment of morphology and phase state during dynamic atmospheric processes.

GCPII Inhibition in Macrophages Delays Age-related Muscle Atrophy in Mice

Age-related loss of muscle mass and strength (Sarcopenia) significantly impairs quality of life in the elderly, yet lacks effective treatments. We previously demonstrated that inhibition of GCPII delayed muscle function decline and neuromuscular junction (NMJ) denervation in an amyotrophic lateral sclerosis (ALS) animal model. As sarcopenia shares NMJ deterioration with ALS, we tested the potent GCPII inhibitor 2-(phosphonomethyl)-pentanedioic acid (2-PMPA) in aging mice, and found that it also preserved muscle function and NMJ integrity. By immunofluorescent staining, we demonstrated that aged mice muscles were associated with GCPII-positive infiltrating macrophages. We next developed a macrophage-targeting GCPII inhibitor delivery system by covalently attaching 2-PMPA to 4th-generation polyamidoamine (G4-PAMAM) dendrimers (D-2-PMPA). The D-2-PMPA was found to inhibit GCPII with IC50= 3.50±0.05 nM. Aged mice muscle showed increased GCPII activity specifically in CD11b+ enriched macrophage cells (138.6±3.0 vs. 336.6±52.9; p<0.05) but not in CD11b− cells. Systemic D-2-PMPA therapy (20 mg/kg 2-PMPA equivalent; IP 3 × /week) completely inhibited the elevated GCPII activity (336.5±52.8 vs. 21.8±9.2 fmol/mg/h; p<0.001). 5-months of D-2-PMPA therapy initiated with 15-month-old mice significantly preserved calf muscle volume (95.0±0.8% vs. 90.4±0.7%; p <0.001), enhanced isometric force (230.2±13.3 vs. 184.0±9.0 mN, female p<0.05; 257.3±21.0 vs. 189.7±19.3 mN, male p<0.05), improved grip strength (96.1±1.6 vs. 90.2±2.2 % of maximum p<0.001) and increased rotarod latency (119.0±6.6 vs. 93.5±9.3 s, female p<0.05; 104.5±5.2 vs. 79.3±4.2 s, male p<0.001). Age-related decline of nerve signal conductivity to muscles was also delayed with D-2-PMPA as observed by improved compound muscle action potential (CMAP) latency (1.28±0.02 vs. 1.38±0.04 ms; p< 0.05) and amplitude (15.2±0.5 vs. 1.27±0.6 mV; p<0.01). Furthermore, NMJ integrity was preserved with treatment as demonstrated by single fiber jitter (5.4±0.3 vs. 7.5±0.5 μs; p<0.01). Overall, our current results support that excessive GCPII activity in muscle macrophages is associated with age-related muscle atrophy, which is improved by GCPII inhibition. This study highlights GCPII inhibition in macrophages as a new therapeutic approach to delay sarcopenia. R01AG078181, R01AG068130, R01NS093416. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Selective targeting of chemically modified miR-34a to prostate cancer using a small molecule ligand and an endosomal escape agent

Use of tumor-suppressive microRNAs (miRNAs) as anti-cancer agents is hindered by the lack of effective delivery vehicles, entrapment of the miRNA within endocytic compartments, and rapid degradation of miRNA by nucleases. To address these issues, we developed a miRNA delivery strategy that includes (1) a targeting ligand, (2) an endosomal escape agent, nigericin and (3) a chemically modified miRNA. The delivery ligand, DUPA (2-[3-(1,3-dicarboxy propyl) ureido] pentanedioic acid), was selected based on its specificity for prostate-specific membrane antigen (PSMA), a receptor routinely upregulated in prostate cancer-one of the leading causes of cancer death among men. DUPA was conjugated to the tumor suppressive miRNA, miR-34a (DUPA-miR-34a) based on the ability of miR-34a to inhibit prostate cancer cell proliferation. To mediate endosomal escape, nigericin was incorporated intothe complex, resulting in DUPA-nigericin-miR-34a. Both DUPA-miR-34a and DUPA-nigericin-miR-34a specifically bound to, and were taken up by, PSMA-expressing cellsinvitro and invivo. And while both DUPA-miR-34a andDUPA-nigericin-miR-34a downregulated miR-34a target genes, only DUPA-nigericin-miR-34a decreased cell proliferation invitro and delayed tumor growth invivo. Tumor growth was further reduced using a fully modified version of miR-34a that has significantly increased stability.

Posaconazole-glutaric acid cocrystal tablet with improved Dissolution rate

Posaconazole is used to prevent fungal infections in patients having severely weakened immune system and has poor aqueous solubility which impairs its dissolution in upper gastric fluid producing problems in different formulations. These characteristics hinder its therapeutic application by delaying absorption rate and thereby onset of action. In the present study, an attempt was made to prepare posaconazole cocrystals with improved physicochemical properties for better therapeutic activity. Cocrystals were prepared with glutaric acid in 1:1 molar using ethanol by solvent drop grinding technique. The co-crystals formed were characterized by melting point determination, fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and dissolution studies. Posaconazole-glutaric acid co-crystals were further formulated as fast disintegrating tablets. The IR study revealed the shifting of characteristic bands of posaconazole. The PXRD pattern indicated cocrystal crystallinity and a considerable difference in 2θ value of intense peaks. The variation in fusion endotherm, which is in agreement with melting point, was designated by DSC spectra of posaconazole cocrystal. A significant improvement in the dissolution rate was observed in the case of cocrystals based tablets than pure posaconazole tablets.

Rapid formation of imidazolium glutarate (IMGA) compound and investigation of its single crystal growth by modified vertical Bridgman technique for optical limiting applications

In this paper, we have examined the formation of the imidazole glutarate adduct by protonation-deprotonation between imidazole and glutaric acid using a direct precipitation method within a short period. Following that, we have succeeded in growing imidazolium glutarate (IMGA) single crystaldirectly from synthesized material and we have also grown IMGA single crystal from the melt methodusing the vertical Bridgman technique for the first time in literature. A special Bridgman furnace was constructed with a slight modification in the winding section for this crystal growth. Crystal structure, phase purity, and growth plane were analyzed for the grown crystal from both single and powder XRD analysis. Functional groups were verified after the growth using FTIR transmittance analysis. The optical homogeneity and growth mechanism were scrutinized by birefringence interferogram and chemical etching studies, respectively. The grown IMGA has 80 % transparency in the entire visible region. The cut-off wavelength of the grown crystal is 235 nm, and the optical band gap energy of IMGA was found to be 5.26 eV. The photocurrent study reveals that IMGA has a negative photoconductivity nature. Third-order nonlinear parameters were found by the Z-scan technique. IMGA has a self-defocusing nature, negative non-linearity, and saturated absorption properties. The calculated χ(3) value is 2.045 x 10-8 esu.

Effects of systemic pretreatment with the NAALADase inhibitor 2-PMPA on oral methamphetamine reinforcement in C57BL/6J mice.

Repeated exposure to methamphetamine (MA) in laboratory rodents induces a sensitization of glutamate release within the corticoaccumbens pathway that drives both the rewarding and reinforcing properties of this highly addictive drug. Such findings argue the potential for pharmaceutical agents inhibiting glutamate release or its postsynaptic actions at glutamate receptors as treatment strategies for MA use disorder. One compound that may accomplish both of these pharmacological actions is the N-acetylated-alpha-linked-acidic dipeptidase (NAALADase) inhibitor 2-(phosphonomethyl)pentanedioic acid (2-PMPA). 2-PMPA elevates brain levels of the endogenous agonist of glutamate mGluR3 autoreceptors, N-acetyl-aspartatylglutamate (NAAG), while potentially acting as an NMDA glutamate receptor antagonist. Of relevance to treating psychomotor stimulant use disorders, 2-PMPA is reported to reduce indices of both cocaine and synthetic cathinone reward, as well as cocaine reinforcement in preclinical rodent studies. Herein, we conducted three experiments to pilot the effects of systemic pretreatment with 2-PMPA (0-100 mg/kg, IP) on oral MA self-administration in C57BL/6J mice. The first experiment employed female mice with a prolonged history of MA exposure, while the mice in the second (females) and third (males and females) experiment were MA-naïve prior to study. In all experiments, mice were trained daily to nose-poke for delivery of unadulterated MA solutions until responding stabilized. Then, mice were pretreated with 2-PMPA prior to operant-conditioning sessions in which nose-poking behavior was reinforced by delivery of 120 mg/L or 200 mg/L MA (respectively, in Experiments 1 and 2/3). Contrary to our expectations, 30 mg/kg 2-PMPA pretreatment altered neither appetitive nor consummatory measures related to MA self-administration. In Experiment 3, 100 mg/kg 2-PMPA reduced responding in the MA-reinforced hole, as well as the number of reinforcers earned, but did not significantly lower drug intake. These results provide mixed evidenced related to the efficacy of this NAALADase inhibitor for reducing oral MA reinforcement in female mice.

Synergistic effect of KI on corrosion inhibition of carbon steel by Styphnolobium japonicum (L.) Schott in H2SO4 solution

This work explored the synergistic effect of Styphnolobium japonicum (L.) Schott extract (SE) and potassium iodide (KI) on the corrosion inhibition of carbon steel (CS) in 0.5 mol/L H2SO4 solution. Firstly, the functional groups in the SE were identified using FTIR. The results of UPLC–Q–TOF–MS analysis confirmed the major phytoconstituents presence in SE were Glutaric acid, 2,3-Dihydroxybenzoic acid, Oxoadipic acid, Isoleucine, 2-Oxovaleric acid, l-phenylalanine, Indoline, and Trigonelline. Further a comprehensive investigation of anticorrosive properties of SE in the absence and presence of KI was conducted employing various techniques, including electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), ultraviolet visible spectroscopy (UV‒vis), and X-ray photoelectron spectroscopy (XPS) and theoretical studies like quantum chemical calculations (QC) and molecular dynamics simulations (MS). The results demonstrated that the SE+KI blend outperforms SE or KI individually, achieving an appreciable corrosion inhibition of 94.6 % for CS in H2SO4 solution. SEM analysis confirmed that the CS surface was smoother when SE+KI was added in the aggressive solution. Theoretical calculations were carried out to determine the dipole moments, Mulliken charges, and Fukui parameters of the eight major molecules found in SE. The results showed that SE can inhibit corrosion.

Microbial and metabolomic profiles of type 1 diabetes with depression: A case-control study.

Depression is the most common psychological disorder in patients with type 1 diabetes (T1D). However, the characteristics of microbiota and metabolites in these patients remain unclear. This study aimed to investigate microbial and metabolomic profiles and identify novel biomarkers for T1D with depression. A case-control study was conducted in a total of 37 T1D patients with depression (TD+), 35 T1D patients without depression (TD-), and 29 healthy controls (HCs). 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) metabolomics analysis were conducted to investigate the characteristics of microbiota and metabolites. The association between altered microbiota and metabolites was explored by Spearman's rank correlation and visualized by a heatmap. The microbial signatures to discriminate TD+ from TD- were identified by a random forest (RF) classifying model. In microbiota, 15 genera enriched in TD- and 2 genera enriched in TD+, and in metabolites, 14 differential metabolites (11 upregulated and 3 downregulated) in TD+ versus TD- were identified. Additionally, 5 genera (including Phascolarctobacterium, Butyricimonas, and Alistipes from altered microbiota) demonstrated good diagnostic power (area under the curve [AUC] = 0.73; 95% CI, 0.58-0.87). In the correlation analysis, Butyricimonas was negatively correlated with glutaric acid (r = -0.28, p = 0.015) and malondialdehyde (r = -0.30, p = 0.012). Both Phascolarctobacterium (r = 0.27, p = 0.022) and Alistipes (r = 0.31, p = 0.009) were positively correlated with allopregnanolone. T1D patients with depression were characterized by unique profiles of gut microbiota and serum metabolites. Phascolarctobacterium, Butyricimonas, and Alistipes could predict the risk of T1D with depression. These findings provide further evidence that the microbiota-gut-brain axis is involved in T1D with depression.

Synthesis, Computational Study, and In Vitro α-Glucosidase Inhibitory Action of 1,3,4-Thiadiazole Derivatives of 3-Aminopyridin-2(1H)-ones.

This article reports on the synthesis of nine promising new 1,3,4-thiadiazole derivatives based on 3-aminopyridones, containing various acidic linkers. The synthesis was carried out by cyclizing the corresponding thiohydrazides 4a-c and anhydrides of glutaric, maleic, and phthalic acids upon heating in acetic acid solution. The conducted bio-screening of the synthesized new 1,3,4-thiadiazole derivatives containing different acidic linkers (butanoic, acrylic, and benzoic acids) showed that they have significant inhibitory activity against α-glucosidase (up to 95.0%), which is 1.9 times higher than the value for the reference drug acarbose (49.5%). Moreover, one of the 1,3,4-thiadiazole derivatives with a benzoic acid linker-2-(5-((6-Methyl-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridin-3-yl)carbamoyl)-1,3,4-thiadiazol-2-yl)benzoic acid (9'b)-showed an IC50 value of 3.66 mM, nearly 3.7 times lower than that of acarbose (IC50 = 13.88 mM). High inhibitory activity was also shown by 1,3,4-thiadiazole derivatives with a butanoic acid linker (compounds 7b, 7c)-with IC50 values of 6.70 and 8.42 mM, respectively. A correlation between the structure of the compounds and their activity was also established. The results of molecular docking correlated well with the bioanalytical data. In particular, the presence of a butanoic acid linker and a benzoic fragment in compounds 7b, 7c, and 9b increased their binding affinity with selected target proteins compared to other derivatives 3-6 (a-c). Calculations according to Lipinski's rule of five also showed that the synthesized compounds 7b, 7c, and 9b fully comply with Ro5 and meet all criteria for good permeability and acceptable oral bioavailability of potential drugs. These positive bioanalytical results will stimulate further in-depth studies, including in vivo models.

Identification of Key Factors in Cartilage Tissue During the Progression of Osteoarthritis Using a Non-targeted Metabolomics Strategy

This research was to reveal the key factors in the progression of osteoarthritis (OA) using non-targeted metabolomics and to find targeted therapies for patients with OA. Twenty-two patients with knee OA scheduled for total knee arthroplasty were divided into two groups: Kellgren–Lawrence (KL) grade 3 (n = 16) and grade 4 (n = 6), according to plain X-rays of the knee. After the operation, the cartilages of femur samples were analyzed using non-targeted metabolomics. When compared with grade 3 patients, the levels of choline, 2-propylpiperidine, rhamnose, and monomethyl glutaric acid were higher; while 1-methylhistamine, sphingomyelin (SM) (d18:1/14:0), zeranol, 3- (4-hydroxyphenyl)-1-propanol, 5-aminopentanamide, dihydrouracil, 2-hydroxypyridine, and 3-amino-2-piperidone were lower in grade 4 patients. Furthermore, some metabolic pathways were found to be significantly different in two groups such as the pantothenate and coenzyme A (CoA) biosynthesis pathway, the glycerophospholipid metabolism pathway, histidine metabolism pathway, lysine degradation pathway, glycine, serine and threonine metabolism pathway, fructose and mannose metabolism pathway, the pyrimidine metabolism pathway, and beta-alanine metabolism pathway. This work used non-targeted metabolomics and screened out differential metabolites and metabolic pathways, providing a reliable theoretical basis for further study of specific markers and their specific pathways in the progression of OA.

Abstract A014: ClpP drives efficacy and mediates acquired resistance with imipridones ONC201 and ONC206 in glioma in vitro

Abstract A014: ClpP drives efficacy and mediates acquired resistance with imipridones ONC201 and ONC206 in glioma <i>in vitro</i>

Solder joints on thick printed copper substrates

This article addresses the soldering of larger components onto ceramic substrates with thick printed copper patterns with a reduced amount of flux or using glutaric acid as a flux substitute. The main goal of the research was to create high quality connections by soldering on ceramic substrates, together with elimination of conventional flux from the process, and also to study the reliability of soldered joints on ceramic substrates under thermal shock ageing. The mock-up chips were used in the test and for this reason the test was primarily focused on bottom joint in the structure or sandwich structures. In the experiment, vacuum soldering using formic acid vapors to reduce oxides was used. Then all samples were observed under X-RAY radiation and selected samples were submitted for thermal shock testing (-40°C / 125°C / 1000 cycles). After the shock testing, another X-RAY scan with void area measurement and shear strength testing were realized. The results showed that our contacting soldering processes on ceramic substrates (with diluted flux or glutaric acid) are applicable and the selected samples also endures the shock ageing, especially bottom joint between ceramic substrate with Cu layer and solder alloy. The results also showed that void area and mechanical shear strength of soldered ceramic samples created with diluted flux or glutaric acid are relatively comparable with standard samples (FR-4).

In Situ Monitoring of Competitive Coformer Exchange Reaction by 1H MAS Solid-State NMR.

In a competitive coformer exchange reaction, a recent topic of interest in pharmaceutical research, the coformer in a pharmaceutical cocrystal is exchanged with another coformer that is expected to form a cocrystal that is more stable. There will be a competition between coformers to form the most stable product through the formation of hydrogen bonds. This will cause destabilization of the pharmaceutical products during processing or storage. Therefore, it is important to develop a mechanistic understanding of this transformation by monitoring each and every step of the reaction, employing a technique such as 1H nuclear magnetic resonance (NMR). In this study, an in situ monitoring of a coformer exchange reaction is carried out by 1H magic angle spinning (MAS) solid-state NMR (SSNMR) at a spinning frequency of 60 kHz. The changes in caffeine maleic acid cocrystals on addition of glutaric acid and caffeine glutaric cocrystals on addition of maleic acid were monitored. In all of the reactions, it has been observed that caffeine glutaric acid Form I is formed. When glutaric acid was added to 2:1 caffeine maleic acid, the formation of metastable 1:1 caffeine glutaric acid Form I was observed at the start of the experiment, indicating that the centrifugal pressure is enough for the formation. The difference in the end product of the reactions with a similar reaction pathway of 1:1 and 2:1 reactant stoichiometry indicates that a complete replacement of maleic acid has occurred only in the 1:1 stoichiometry of the reactants. The polymorphic transition of caffeine glutaric acid Form II to Form I at higher temperatures was a crucial reason that triggered the exchange of glutaric acid with maleic acid in the reaction of caffeine glutaric acid and maleic acid. Our results are novel since the new reaction pathways in competitive coformer exchange reactions enabled understanding the remarkable role of stoichiometry, polymorphism, temperature, and centrifugal pressure.

Evaluating the effects of azelaic acid in the metabolism of Arabidopsis thaliana seedlings through untargeted metabolomics and ionomics approaches.

The present study demonstrates that low concentrations of azelaic acid (AZA) significantly impact the metabolism of Arabidopsis thaliana seedlings, leading to imbalances in numerous minerals and metabolites due to AZA-induced stress. Untargeted metabolomic analyses were conducted on untreated and AZA-treated seedlings at two time points: 7 and 14 days after treatment initiation. The results revealed a general accumulation of sugars (e.g., glucose, mannose, xylose), amino acids (e.g., lysine, GABA, threonine, glutamine), and organic acids (e.g., glutaric acid, shikimic acid, succinic acid) in AZA treated-seedlings, suggesting that AZA triggers stress responses in Arabidopsis. Ionomic analysis revealed that AZA induces phosphorus deficiency, which plants compensate by increasing malate content in the roots. Additionally, AZA treatment induced putrescine accumulation within the root, a metabolic biomarker of potassium deficiency and plant stress. The metabolomic profile showed elevated levels of different specialized metabolites, such as nitrogen- and sulphur-containing compounds, and altered levels of various phytohormones, including jasmonates and brassinosteroids, implicated in plant protection under biotic and/or abiotic stresses. These findings support the hypothesis that AZA's mode of action is associated with an auxin imbalance, suggesting its function as an auxinic herbicide. The observed increases in starch and jasmonates, coupled with the disruptions in potassium homeostasis, are linked to the previously reported alterations in the auxin transport, root architecture and gravitropic root response. Statistical analyses were applied, including Kruskal-Wallis tests for ionomic data, as well as multifactor analysis, Principal Component Analysis, Orthogonal Partial Least Squares-Discriminant Analysis, and enrichment pathway analysis for metabolomic data, ensuring the robustness and validity of these findings.

Temperature-Controlled Hydrothermal Synthesis of α-MnO2 Nanorods for Catalytic Oxidation of Cyclohexanone.

This work describes the comparison of the catalytic performances of α-MnO2 nanorods synthesized by a facile hydrothermal approach at varying temperatures (140-200 °C). The structure and morphology of these nanorods were analyzed by XRD, N2-physisorption, NH3-TPD, Raman, SEM, HRTEM, and XPS. The prepared α-MnO2 nanorods also performed exceptionally well in the catalytic oxidation of cyclohexanone to dicarboxylic acids under mild reaction conditions. The characterization results conferred that there is a significant influence of hydrothermal temperatures on the textural properties, morphology, and catalytic activity. Notably, the α-MnO2 nanorods obtained from 180 °C hydrothermal conditions outperformed other catalysts with 77.3 % cyclohexanone conversion and 99 % selectivity towards acid products such as adipic acid (AA), glutaric acid (GA) and succinic acid (SA). The improved catalytic activity may be attributed to the interaction of the bifunctional Mn3+/4+ redox metal centres and surface acidic sites. The present oxidation reaction was found to be a promising eco-benign process with high selectivity for the production of commercially significant carboxylic acids from cyclohexanone.

Insight into using hydrochar to alleviate ammonia nitrogen inhibition during anaerobic digestion of waste activated sludge: Performance, metagenomic and metabolomic signatures

In this study, hydrochar (HCR) was used to alleviate high ammonia inhibition to the anaerobic digestion (AD) of waste activated sludge (WAS) and to elucidate the inner microorganism mechanism. After HCR addition, the cumulative methane yield increased by 73.6 % and 35.6 % under ammonia inhibition levels of 3000 and 6000 mg/L, respectively. Metagenomic analysis showed that HCR enriched the diversity of hydrogenotrophic methanotrophs, and the relative abundances of functional microorganisms with electron transfer capabilities (Geobacteraceae bacterium etc.) were 1.5–7.8 times higher than those without HCR addition. Metabolomics analysis implied that metabolites related to fatty acid degradation, such as glutaric acid and hexadecanal, were downregulated (2.9–15.7 %) under ammonia inhibition conditions and that HCR regulates metabolites in the methane metabolic pathway. Moreover, HCR changed the methanogenic pathway from hydrogenotrophic methanogenesis to multiple pathways under ammonia inhibition conditions, especially methanolic and methylotrophic methanogenesis, which facilitated the methane yield. This study provides valuable information for understanding the inner microbial mechanism of HCR addition on alleviating high ammonia inhibition to AD of WAS, and gives basic knowledge for the application of AD of WAS under ammonia inhibition conditions.