Methanogenic archaea are responsible for roughly 14% of global methane emissions, so disrupting their methane production could substantially lower these emissions. The methyl-coenzyme M reductase (MCR) complex, encoded by mcrA, mcrB, and mcrG, catalyzes the final step of methane formation. Here we used computational methods to design a small interfering RNA (siRNA), conceived as an RNA interference (RNAi)-like antisense oligonucleotide, that targets a region of the mcrA gene conserved across eight methanogen species spanning five taxonomic orders. A 14-step computational pipeline was used to retrieve mcrA sequences, align them, identify a 40-nucleotide window with 96.9% mean conservation, and select the best 19-nucleotide guide strand by energy scoring. The guide strand (5'-UGCCUGCUUUGAUGCCUGC-3') targets the mRNA sequence 5'-GCAGGCAUCAAAGCAGGCA-3' and has a GC content of 57.9%. ViennaRNA analysis gave a target mRNA minimum free energy (MFE) of -8.20 kcal/mol and a guide-strand MFE of -2.10 kcal/mol; co-folding of the siRNA–mRNA duplex yielded an MFE of -41.20 kcal/mol, indicating a stable pairing. Structural-diversity analysis identified 22 siRNA and 94 mRNA conformations within 5 kcal/mol of the MFE, and the target site was highly accessible (mean unpaired probability of 0.581). RNA–RNA pairing in an antiparallel A-form duplex showed 49 Watson–Crick hydrogen bonds, 36 pi-stacking interactions, and 5 metal-coordinating contacts across the 19 base pairs. All-atom molecular dynamics at 300 K using OpenMM (AMBER14 force field, GBn2 implicit solvent) showed a mean potential energy of about -3,754 kcal/mol, a backbone RMSD that converged to a plateau of 8.2 Å, and a stable radius of gyration (17.4 Å), consistent with a flexible single-stranded guide. This conserved, multispecies target makes the designed guide a strong candidate for experimental validation as a biotechnological route to reduce livestock methane emissions.
This study aimed to investigate the correlation between vitamin D-binding protein (DBP) gene polymorphisms at rs4588 and rs7041 loci and the prevalence and mortality rates of the coronavirus disease 2019 (COVID-19) up to 2022. In addition, the study sought to conduct a current situation analysis regarding vaccination among the populations of 10 countries, including Türkiye. The study examined the relationships between the COVID-19 prevalence and mortality rates and the frequencies of different genotypes according to rs7041 and rs4588 loci, which were collected from the literature. Total number of the COVID-19 cases and mortality rate because of SARS-CoV-2 infection before and after vaccination, and the vaccine data, including all types of vaccines, were collected from the World Health Organization coronavirus dashboard in 2022. The data from China, Japan, Nigeria, Kenya, Mexico, Italy, Türkiye, Finland, Germany, and Czechia was included. The mortality rates in China, Nigeria, Mexico, and Italy decreased significantly after the vaccination (P < 0.05), while the prevalence of COVID-19 after the vaccination was not affected in all the countries included (P > 0.05). It was observed that the higher the frequency of GG and GT genotypes of rs7041, the higher the prevalence of COVID19 (P = 0.02 and P = 0.01, respectively), but only frequency of GT genotype was directly associated with increasing mortality rates in all countries during pre-vaccination period (P < 0.01). There was a significant inverse relationship between the frequency of TT genotype of rs7041 and the prevalence of COVID-19 (P = 0.02), but the relationship with mortality rate was not significant in all countries (P > 0.05). No significant correlation was found between the frequencies of AA, AC and CC genotypes of rs4588, and the COVID-19 prevalence and mortality rates in all countries (P > 0.05). Our findings suggest that the vaccination did not change the prevalence of COVID-19 but decreased mortality rates in four of the 10 countries studied. Significant correlations were observed in the frequencies of rs7041 single nucleotide polymorphism (SNP) with the COVID-19 prevalence and mortality rates, while no correlation was observed in those of rs4588 SNP.
The effect of three different yeast species (Saccharomyces cerevisiae, Saccharomyces cariocanus, and Schizosaccharomyces pombe) on bioethanol production from groundnut shells was investigated at exactly same process conditions i.e temperature of 35 and five days fermentation period. The physicochemical properties of the generated bioethanol from the optimal yeast species (Saccharomyces cariocanus) was also evaluated. It was found that the descending sugar concentrations were similar across all the three species (72.76–74.35 mg/dL) with negligible variations. However, significant variations were observed in bioethanol quantity and percentage yield. Saccharomyces cariocanus generated the highest quantity of bioethanol (102 mL) and yield (34%), followed by saccharomyces cerevisiae (90 mL, 30%), with Schizosaccharomyces pombe having the lowest performance (73 mL, 24%). This reveals the superior fermentative efficiency of Saccharomyces cariocanus in converting sugars to ethanol. The physicochemical properties of bioethanol produced by Saccharomyces cariocanus were generally comparable to ASTM standards (indicating acceptable fuel quality) with slight deviations in density and boiling point which could be attributed to impurities. The study emphasizes the importance of yeast species selection in enhancing bioethanol production from groundnut shell feedstocks and identifies Saccharomyces cariocanus as a promising yeast for effective ethanol fermentation. It is concluded that groundnut shells are promising feedstock for bioethanol production but further process optimization is required to fully meet fuel standards.
New regimes of treatments and delivery systems are of great need today because of the increasing emergence of antimicrobial resistance among pathogens. In this study, initially liposomes were prepared comprising mycosynthesized silver nanoparticles in combination with meropenem. As a result of this combination, nanosomes were designed. In vitro analysis of the prepared formulation was done to check its effectiveness against MDR Salmonella typhi. Extracellular synthesis of (AgNPs) silver-nanoparticles through Aspergillus fumigatus BTCB01 was conducted. The particles were then characterized through by a zeta sizer, and they had particle size (299.6 nm), zeta potential (-2.64 mV) with a polydispersity value (0.4). Different liposomal formulations were prepared and characterized, each with different in size i.e. control liposomes had 318.7 nm, drug-encapsulated liposomes had 237.4 nm, silver-nanoparticles incorporated liposomes had 320.3 nm and Silver-nanoparticles incorporated drug liposomes had 215.3 nm size with different zeta potential and polydispersity index for each, i.e. -45.8 (PDI:0.3), -41.3 (PDI:0.3), -42.5 (PDI:0.4) and -39.6 mV (PDI:0.3), respectively, signifying a good stabile and homogeneous solution. Meropenem encapsulated liposomes had (94%) encapsulation efficiency, whereas Silver-nanoparticles incorporated drug liposomes had (86%) encapsulation efficiency. The release study of drugs through dialysis membranes graded in order of drug encapsulated liposomes ˃ Silver-nanoparticles incorporated drug liposomes ˃ control liposomes. In vitro analysis revealed that the antibacterial assay through the disk diffusion method revealed that drug-encapsulated liposomes showed a 1-fold increase in activity as compared to those which were incorporated with the silver nanoparticles. Conclusively, the addition of silver nanoparticles did not affect the stability of liposomes; however, they affected the encapsulation efficiency and drug release property of the delivery system.
The dentate gyrus of the hippocampus is emerging as a focal target in pattern separation and completion in recent years. Adult neurogenesis in the subgranular zone further provides a unique developmental advantage to this region by supporting the regional activity of newborn granule cells, when required. The contribution of adult-born granule cells (AdB GCs) to the local circuits can be attributed to their differences from embryonic-born mature GCs in terms of their morphological and biophysical characteristics. AdB GCs are highly excitable cells that show sparse activity. In this study, our focus was on how the morphological distinction of early AdB GCs from mature GCs affects their responsiveness. The reduced multi-compartmental conductance-based models are designed on Python environment with Brian2 module with simple Hodgkin-Huxley type Na and K conductances. Our results indicate that the early morphology of AdB GCs is optimized for faster action potential kinetics and higher excitability compared to mature GCs, even without any biophysical differences.
Aliarcobacter butzleri is an emerging foodborne and zoonotic pathogen, yet many of its encoded proteins remain functionally uncharacterized. This lack of annotation limits understanding of its molecular mechanisms and hampers the identification of novel therapeutic targets. In this study, we systematically performed functional annotation of essential hypothetical proteins from the BNI-3166 strain using an integrative-in-silico approach to uncover potential drug and vaccine candidates. 2,367 protein-coding sequences were retrieved from the RefSeq database and were identified 356 as hypothetical proteins. Using BLASTp, we screened these HPs against the Database of Essential Genes and the human proteome to identify essential non-homologous proteins, resulting in 20 ENH candidates. Functional annotation was performed using several domain-based databases, including Pfam, InterPro, SMART, and SUPERFAMILY. Subsequently, physicochemical properties were analyzed and predicted subcellular localization using PSORTb and CELLO. To assess druggability, the ChEMBL database was used. Virulence factors using VFDB, VICMpred, and VirulentPred 2.0 were also predicted. Gene Ontology annotations were generated via ARGOT2.5. Furthermore, we explored protein-protein interactions using STRING and predicted tertiary structures with AlphaFold3. Moreover, Ligand binding pockets were predicted using PrankWeb, and antigenicity of vaccine candidates was assessed using VaxiJen v2.0. We identified 20 essential non-homologous hypothetical proteins, of which 10 were confidently annotated based on conserved domain analysis. These proteins were classified as enzymes, binding proteins, transporters, regulatory proteins, and potential virulence factors. Among them, eight exhibited characteristics of promising drug targets, while two showed potential as vaccine candidates based on subcellular localization. Druggability analysis revealed that nine proteins had no similarity to known drug targets, suggesting novel therapeutic potential. Predicted 3D structures generated using AlphaFold3 yielded pTM scores ranging from 0.44 to 0.92, indicating acceptable to high modeling confidence. Ligand binding site analysis confirmed druggability in six candidates, and antigenicity screening identified one protein as a potential vaccine target. This study provides a computational framework for identifying functionally important proteins in A. butzleri BNI-3166 and highlights novel therapeutic candidates for experimental validation, offering new directions in drug and vaccine development against this underexplored pathogen.
Pine tar has long been valued for its dermatological and antimicrobial properties; however, its volatile and semi-volatile component profile remains underexplored from a sustainable bioprospecting perspective. In this study, we combined dispersive liquid–liquid microextraction (DLLME) with GC-MS to develop a rapid, green workflow for profiling pine-tar volatiles, achieving greater than or equal to 50-fold enrichment from a 100 mg sample in under 10 min. GC-MS analysis on a TRB-5MS column (90 min gradient) resolved 45 compounds (match ≥ 77 %), with sesquiterpenes accounting for 71.3 % of the total area (isolongifolene 30.3 %; isobornyl acetate 16.0 %; borneol 12.4 %; (+)-longicyclene 12.5 %). Monoterpene alcohols comprised 4.4 %, while minor oxidized derivatives contributed < 3 %. Compared to conventional hydrodistillation, DLLME reduced chlorinated solvent usage by 90 % and enhanced recovery of high-boiling terpenoids by ~ 25 %. Furthermore, the cytotoxic effect of pine tar was investigated on human umbilical vein/vascular endothelium cells (HUVEC) using 3-[4,5-dimethylthiazol-2-yl]-5[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium (MTS) cell viability assay, revealing a low level of toxicity. The resulting chemical fingerprint high lights the biotechnological potential of sesquiterpene scaffolds such as isolongifolene for microbial production and biocatalytic transformations. It also supports enzyme-based functionalization strategies for isobornyl acetate and borneol, and opens avenues in sustainable perfumery, pharmaceutical intermediates, and biofuel applications. This semi-quantitative and eco-friendly platform offers a practical foundation for the biotechnological valorization and green production of pine-tar terpenoids. In addition, the observed low cytotoxicity of pine tar contributes to the preliminary safety assessment of this natural product on human endothelial cells.
The Stimulator of Interferon Genes (STING) protein is a transmembrane protein encoded by the STING1 gene. It is a critical component of the innate immune system, which serves as a sensor for cytosolic DNA and plays a crucial role in activating the Type-I interferon pathway. The enzyme cyclic GMP-AMP synthase (cGAS) binds to DNA and assists in the synthesis of cyclic GMP-AMP (cGAMP) from GTP and ATP. This reaction stimulates the activation of TANK-binding kinase 1 (TBK1), an enzyme involved in signaling pathways that result in the phosphorylation of STING. The interaction between STING, TBK1, and IRF3 selectively interferes with IRF3 phosphorylation without obstructing TBK1 activation, leading to mutations in STING. This process indicates that STING functions as a scaffold protein, guiding and supporting TBK1’s phosphorylation of IRF3. IRF3 activation occurs when STING’s C-terminal tail (CTT) binds to IRF3, leading to conformational change. STING’s CTT tail plays a crucial structural and functional role in regulating innate immune responses. Understanding the structure of the CTT loop is vital for unraveling the mechanism of STING-mediated signaling. In this study, we performed molecular dynamics (MD) simulations to investigate the importance of the CTT loop for STING activation through comparing the molecular interactions within STING-TBK1 complexes in their inactive and active states. We integrated the findings of previous modeling studies into our simulations.
Higher levels of ferritin were associated with severe forms of COVID-19 disease. Given the above, our goal was to investigate the associations between ferritin levels within COVID-19-infected individuals from the Adjara population (Georgia). A nasopharyngeal swab was collected from 318 individuals, and SARS-CoV-2 infection was detected using the polymerase chain reaction (PCR) method. Ferritin levels were also investigated in the blood serum of the same individuals. Thus, the study of ferritin in COVID-19 patients (in the Adjara population revealed significantly higher ferritin levels in COVID-19 patients. Higher levels of ferritin were detected in the male subjects than in the female population (p=0.0001). COVID-19 patients with lethal outcomes had nearly ~3 times higher levels of ferritin than the reference value, while those who successfully recovered had ~1.9 times above the reference value. It should be noted that the individuals with lethal outcomes were between 81 and 90 years old. An increased level of D-dimer compared to the reference level was also detected in the male population and was nearly ~4.1 times higher in those with lethal outcomes. D-dimer was also significantly increased in patients at the age 71-80 years, while their CRP levels were approximately ~5.8 times above the reference level; Moreover, CRP level was ~24.4 times increased in the case of women with lethal outcomes; In particular, according to the comparing age groups, a high level of CRP was observed in 61-70 years patients. Our study revealed that the diseased population exhibited significantly higher ferritin levels. The ferritin levels in patients with lethal outcomes were considerably higher than those in patients who successfully recovered. Thus, the findings reveal a noteworthy elevation in D-dimer levels, particularly in men and deceased patients, with a notable elevation in the 71-80 age group. Additionally, CRP levels were markedly higher, especially among deceased women and individuals aged 61-70.
Functional gene analysis is crucial for understanding gene roles in biological processes. However, analyzing data with multiple experimental groups presents significant challenges due to the complexity of data processing and the limitations of existing tools. GANGO + BioFuncional, an R-based Shiny application designed for end-users, addresses these challenges by providing a streamlined and comprehensive workflow for functional gene analysis. This interactive and freely available tool requires no installation, thus significantly enhancing its accessibility. The application is composed of two primary modules: GANGO, which efficiently processes input data and performs functional annotation to Gene Ontology (GO) terms and KEGG pathways; and BioFuncional, dedicated to in-depth analysis and interpretation. Key advantages include a highly user-friendly interface that eliminates the need for programming expertise, robust multi-group analytical capabilities, comprehensive visualization tools (interactive networks and significance-driven bar plots), and seamless compatibility with AI-driven interpretation tools like CURIE. Hosted on a server, GANGO + BioFuncional enhances the efficiency and accessibility of functional gene analysis, making it a valuable asset for both specialists and AI applications, ultimately facilitating deeper biological insights.
The recent outbreak of a new coronavirus disease known as COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is a highly contagious and pathogenic viral infection that has spread worldwide. Coronaviruses are known to cause disease in humans, other mammals, and birds. Although specific therapeutics and vaccines require efforts in this direction, reaching the world's population with mutations of the virus can be a difficult target. The major proteases of coronavirus play a critical role during the spread of the disease and therefore still represent an important target for drug discovery. As of now, there is still no official treatment for infected patients. In this study, bioinformatics-based molecular docking studies were performed to identify potent inhibitors of novel candidate molecules against the spike protein S of SARS-CoV-2. The affinities of ligand molecules thought to be effective in the treatment of SARS-CoV-2 disease were investigated. For this purpose, 1,615 different FDA-approved drug ligand molecules were retrieved from ZINC15 database. Crystallographic structure of spike protein S of SARS-CoV-2 was retrieved from Protein Data Bank (PDB). Initial virtual screening was performed using qvina-w, an accelerated version of AutoDock Vina optimized for rapid docking, to evaluate binding affinities of all 1,615 compounds against the spike protein. The top 10 ligands with the most favorable binding affinities were selected for further analysis. These ligands were docked to the target protein with Autodock Vina. The complexes were first solvated and then run through Molecular Dynamics (MD) simulations, utilizing NAMD. The binding energies were computed through these interactions, which are used to compare the affinities of the ligands to the target protein. Ultimately, 10 different ligands capable of inhibiting the spike protein of SARS-CoV-2 were selected and compared based on their affinities.
The demand for tissue scaffolds to support the repair, regeneration, and restoration of damaged tissues is rapidly growing. Scaffolds fabricated using the electrospinning technique are particularly significant in tissue engineering due to their ability to provide micro- to nano-scale porosity and a large surface area. This study focuses on developing tissue scaffolds with enhanced cell adhesion, biodegradability, and tensile strength by employing aqueous solutions of polyvinyl alcohol (PVA), a biocompatible and biodegradable synthetic polymer; gelatin (GEL), a natural polymer that offers binding sites conducive to cell adhesion and differentiation; and synthesized bioceramics, all integrated through the electrospinning process. Composite tissue scaffolds were engineered by incorporating 1% to 3% GEL into the PVA solution, followed by the addition of 1% bioceramics to the 1% GEL-enriched PVA. The composite formulation not only emulates the extracellular matrix as a biomimetic strategy but also goes beyond merely enhancing ossification. Comprehensive structural, morphological, mechanical, and thermal characterizations were conducted to analyze the properties of the scaffolds containing the synthesized bioceramics. The tensile strengths of the fabricated nanocomposites were determined to be 6.25 MPa for 10:0 (PVA:GEL), 7.45 MPa for 10:1 (PVA:GEL), 8.01 MPa for 10:3 (PVA:GEL), and 8.22 MPa for 10:1:1 (PVA:GEL:Bioceramics), respectively, indicating a progressive enhancement in mechanical properties with the incorporation of GEL and bioceramics. The results demonstrate the successful production of a potential biomaterial with ideal properties for tissue engineering applications. These composite scaffolds, providing a conducive environment for cell adhesion and exhibiting excellent mechanical properties, are anticipated to be suitable for dental applications as an intermediate layer which may support bone and connective tissue formation.
Oral infections are a type of infection that occurs in and around the mouth, typically arising when proper oral hygiene is neglected. These infections manifest as symptoms such as mouth sores, dental caries, and periodontal diseases, with dental caries being the most common form. Streptococcus and Lactobacillus bacteria are the primary causative agents in dental caries. These bacteria act as opportunistic pathogens, potentially leading to serious diseases. Moreover, antibiotic resistance is developing in these pathogenic bacteria, limiting treatment options. β-lactam antibiotics are particularly important due to their broad spectrum and selective toxicity. In this study, novel phenethylamine-based β-lactam derivatives were synthesized, and their antibacterial activities against oral pathogens were investigated. The antibacterial activities of the compounds were determined using agar well diffusion and microdilution assays. The study observed that β-lactam derivatives formed inhibitory zones against the growth of oral pathogens, while imine compounds did not form such zones. The diameter of the inhibition zones for the β-lactam compounds ranged from 0.9 to 2.1 cm. The MIC values were calculated to be between 12.5 and 100 μM. These data suggest that β-lactam derivatives could be potent therapeutic agents for oral infections.
This study highlights the effective immobilization of protease from Bacillus sp. in polyvinyl alcohol hydrogels and its characterization. Both free and entrapped proteases exhibited optimal activity at pH 8.0 and 55°C, indicating that the immobilization did not significantly alter the enzyme's fundamental properties. The entrapment in polyvinyl alcohol hydrogels significantly enhanced thermal stability. After 24 hours at 55°C, the free protease retained only 19% of its initial activity, whereas the entrapped protease retained 72%. The entrapped protease showed a longer half-life of 53.3 hours compared to 10.6 hours for the free protease. The Km and Vmax values of free protease were determined to be 0.5 mg/mL and 23.3 U/mg protein, respectively, for casein. These values were found to be 0.2 mg/mL and 23.8 U/mg protein, respectively for the entrapped protease. The entrapped protease retained 58% of its initial activity after 5 reuses in a batch reactor. As a result, the entrapment of Bacillus sp. protease in polyvinyl alcohol is an effective immobilization method due to its simplicity, low cost, and ability to provide a 5-fold increase in thermal stability.
Cancer and Alzheimer's disease (AD) present significant socioeconomic challenges and remain without definitive cures. Existing chemotherapeutic and anti-Alzheimer drugs approved by the FDA offer limited efficacy and carry notable side effects, underscoring the need for safer, more effective therapies. Our research group has recently focused on identifying natural molecules to treat AD by targeting acetylcholinesterase. Building on this, the current study expands our approach through virtual screening of DrugBank and Zinc databases to discover natural compounds that inhibit Estrogen Receptor Alpha (ERα) for breast cancer treatment. Molecular docking and drugability analyzes identified four promising compounds: Queuine, Thiamine, Galantamine, and Folic Acid. The docking scores for Galantamine, Thiamine, Queuine, and Folic Acid were -8.8, -8.3, -8.0, and -7.5 kcal/mol, respectively. These molecules demonstrate interactions with key residues in the ERα binding site such as Glu 353 and Phe 404 through hydrogen bonding and pi-pi stacking. Similar interactions are also maintained in the FDA-approved selective Estrogen Receptor Modulators, Raloxifene and Tamoxifen. ADMET analysis indicated that these natural molecules possess favorable drug-like properties and offer a safety advantage, as they are less likely to induce deep vein thrombosis or pulmonary embolism, which are the serious side effects commonly associated with Raloxifene and Tamoxifen. A thorough literature review further highlights these compounds' neuroprotective effects, suggesting they could serve as dual-purpose therapeutics to address both cancer and AD, paving the way for integrated treatment strategies.
Here, carbon cloth (CC), which is a disposable, inexpensive, conductive substrate, was electrochemically activated for the formation of function al groups on the electrode surface. The electrochemical activation of commercial CC was achieved in various acidic solutions such as 0.1 M H2SO4, 0.1 M HCl and 0.1 M HNO3 to create functional groups on the surface of the gas diffusion layer by applying a constant 100 mA current (galvanostatic) for 10 s, 20 s, and 30 s, respectively. The electrochemical measurements were conducted using a 3-electrode system, including disposable carbon cloth as a working electrode, saturated Ag/AgCl as a reference electrode and Pt wire as a counter electrode. The modified CCs were tested via cyclic voltammetry using 5 mM Fe(CN)63−/Fe(CN)64− redox probe. Electrochemical experiment results showed that acid treatment of CC resulted in a significant increase in peak current compared to bare CC, indicating formation of functional groups on the electrode surface and improved electrical conductivity.
Research has been conducted to explore the genetic basis of trigeminal neuralgia, a persistent pain condition that impacts the trigeminal nerve. COMT is an enzyme responsible for inactivating substances and hormones containing catechol and catecholamines. Previous research has linked COMT gene polymorphism with various pain conditions, including migraine. Our research aimed to investigate the correlation between trigeminal neuralgia and the rs4680 polymorphism of the COMT gene. We conducted a research project which included 10 individuals diagnosed with trigeminal neuralgia and 30 healthy individuals as controls. Following collection of blood samples, we isolated DNA from the samples and then genotyping of COMT rs4680 polymorphism was performed with Real-Time PCR, using TaqMan SNP Genotyping Assay. Among the trigeminal neuralgia patients, 2 of them exhibited the AA genotype, 6 had the AG genotype, and 2 had the GG genotype for COMT rs4680. The AG genotype was notably prevalent. No statistically significant differences in the distributions of COMT genotypes and allele frequencies were found between the experimental (patients) and the control group. However, the AG genotype appeared to be more frequent in the patient group. Moving forward, we plan to expand our study by increasing the number of patients and control subjects. This will enable us to further elucidate the potential relationship between COMT gene polymorphism and trigeminal neuralgia.
Haloperidol is an antipsychotic used in the treatment of schizophrenia. Compared to other antipsychotics, it is widely used in developing countries due to its affordable price. Haloperidol has a narrow therapeutic range and variable pharmacokinetics; therefore, therapeutic drug monitoring (TDM) is recommended. For this reason, in this study, an easily applicable, fast, selective, accurate, reliable, and economical LC-MS/MS method was developed for the determination of haloperidol in human plasma for use in TDM and also method was validated according to European Medicines Agency (EMA) Bioanalytical method validation guidelines. In the developed method, analyte and internal standard were extracted from plasma by salt-assisted liquid-liquid microextraction (SALLME) technique and after that injected to the LC system. The limit of quantification of haloperidol was determined as 1 ng/ml. The calibration curve was validated between 1-15 ng/ml, with correlation coefficients >0.99. In addition, the developed method was used to determine drug concentration levels in the plasma of real patients.
In this study, novel N,S-substituted naphthaquinone analogues (2, 4, 6, and 8) were synthesized from the reactions of previously known aminonaphthaquinone derivatives (1, 3, 5, and 7) with allyl mercaptan. 2-(allylthio)-3-(4-phenylpiperazin-1-yl)naphthalene-1,4-dione (2), 2-(allylthio)-3-(4-(2-fluorophenyl)piperazin-1-yl)naphthalene-1,4-dione (4), 2-(allylthio) -3-(4-benzylpiperidin-1-yl)naphthalene-1,4-dione (6) and 2-(4-chlorophenylamino)-3-(allylthio)naphthalene-1,4-dione (8) were obtained from the reactions of 2-chloro-3-(4-phenylpiperazin-1-yl)naphthalene-1,4-dione (1), 2-chloro-3-(4-(2-fluorophenyl)piperazin-1-yl)naphthalene-1,4-dione (3), 2-(4-benzylpiperidin-1-yl)-3-chloronaphthalene-1,4-dione (5), and 2-(4-chlorophenylamino) -3-chloronaphthalene-1,4-dione (7) with allyl mercaptan according to the general synthesis procedure. Synthesized new naphthaquinone analogues (2, 4, 6, and 8) were purified by column chromatography. The chemical structures of these novel N,S-substituted naphthaquinone analogues were characterized by spectroscopic methods (FT-IR, NMR, and MS).
The effect of platinum (Pt) loadings of air-cathodes in the 0-0.5 mg cm-2 range on single chamber microbial fuel cell (MFC) performance and cathode impedance was evaluated. In MFC tests, reducing benchmarking Pt loading of 0.5 mg cm-2 to 0.1-0 mg cm-2 decreased maximum power density by between 38% and 84%. The decrease in cathode open circuit potential with reduced loadings was small down to a catalyst loading of 0.03 mg cm-2, but was significant when the loading was further reduced to 0.01 or 0 mg cm-2. Impedance measurements of cathodes revealed that both charge-transfer and diffusion resistance increase with decreasing catalyst loadings on cathodes. Charge-transfer resistance of benchmarking cathode increased to a small extent when loadings were reduced to 0.1-0.03 mg cm-2. Below 0.03 mg cm-2, dramatic increase of charge-transfer resistance suggested that 0.03 mg cm-2 can be considered as the minimum Pt loading for which kinetic limitations are not of great concern and can be overcome to a large extent compared to lower loadings. In comparison to charge-transfer resistance, diffusion resistance differed more significantly between the loadings of 0.03 and 0.5 mg cm-2; and it was therefore the main component that changed the internal resistance of these cathodes.
