Hasil untuk "Organic chemistry"

S. Allen, Ryan R Walvoord, Rosaura Padilla-Salinas et al.

N. Connelly, W. Geiger

E. M. Sánchez-Carnerero, A. R. Agarrabeitia, Florencio Moreno et al.

Ivona Veličković, Stevan Samardžić, Marina T. Milenković et al.

Reducing agricultural waste through reuse has become one of the most important strategies to minimise impact on the environment—an emerging global issue. Sunflower ranks fourth in the world in the production of vegetable oilseeds and therefore generates large amounts of agricultural waste. The aim of this study was to investigate the phytochemical composition and bioactivity of sunflower crop residues in order to open up new opportunities for waste management. TPC and TFC were determined spectrophotometrically, while the dominant compounds were identified by LC-DAD-ESI-MS as <i>ent</i>-kaur-16-en-19-oic acid (KA) and 6Ac-7OH-dimethylchromone (DMC). Both compounds were present in higher concentrations in the ethyl acetate fraction (245.5 and 16.8 mg/g, respectively) than in the ethanol extract. None of the tested samples showed antimicrobial effects in the microdilution test. DMC showed remarkable antioxidant activity by DPPH, ABTS, FRAP and TRC in vitro assays, while both compounds proved to be promising enzyme inhibitory agents, being particularly efficient in inhibiting anti-neurodegenerative enzymes (IC₅₀ values of DMC and KA were 1.20/1.37 mg/mL and 1.44/1.63 mg/mL for AChE/BChE, respectively) and tyrosinase. The results presented indicate that sunflower crop residues are a good candidate for the extraction of bioactive compounds with potential application in the food, pharmaceutical and cosmetic industries.

Bjelanović Jasna, Nikolić Aleksandra, Aslan Mutay et al.

Background: Altered sphingolipid levels might contribute to rectal cancer development, progression and therapy response by regulating various biological processes, including apoptosis. This study aimed to analyse the serum sphingolipid profile in rectal cancer patients and investigate its association with the apoptotic status of tumour tissue and therapy response. Methods: Ceramide (CER) and sphingomyelin (SM) serum levels were analysed in 22 patients with locally advanced rectal cancer and 24 healthy individuals by ultrafast liquid chromatography coupled with tandem mass spectrometry. The expression of pro-apoptotic BAX (BCL2 associated X, apoptosis regulator) and anti-apoptotic BCL2 (BCL2 apoptosis regulator) was analysed in tumour and corresponding healthy tissue samples of patients by quantitative real-time PCR. Results: Significantly lower serum levels of C18 CER, C22 CER, C24 CER, C18 SM and C24 SM were observed in patients than in controls (P<0.05). For C20 CER, C22 CER and C24 CER, a positive correlation with the pro-apoptotic status of tumour tissue was found (r=0.619, P=0.018; r=0.694, P=0.006 and r=0.601, P=0.023, respectively). No difference in serum sphingolipid levels was found between patients with good, moderate, and poor responses to therapy. Conclusions: These results support the involvement of sphingolipids in rectal cancer. However, further studies, including a larger cohort of subjects, are needed to clarify the association of sphingolipid metabolites with therapy response.

Maria Rossello-Gelabert, Kevin Las Heras, Ainhoa Gonzalez-Pujana et al.

Abstract Background Mesenchymal stromal cells (MSCs) exert therapeutic effects primarily through their secretome, rich in bioactive factors with immunomodulatory and regenerative properties. However, clinical application of MSC-derived secretome is hindered by donor variability, limited expansion, and replicative senescence. To address these issues, we developed immortalized human hair follicle-derived mesenchymal-like stromal cells (iHF-MSCs) as a consistent and scalable source of therapeutic secretome. Methods HF-MSCs were isolated using a minimally invasive procedure and immortalized with lentiviral SV40 large T antigen. From 576 single-cell clones, C18 and C26 were selected based on proliferation capacity, absence of senescence, and retention of a mesenchymal-like phenotype. Characterization included RT-PCR, flow cytometry for surface markers, trilineage differentiation, and CD56 expression analysis. For immunomodulatory evaluation, cells were licensed with IFN-γ and TNF-α, and the resulting conditioned media (licensed CM) were analyzed by ELISA and cytokine arrays. PBMC proliferation and Treg induction were assessed using licensed CM, while unlicensed CM was tested for its regenerative effects on dermal and epidermal cell functions, including wound repair, tube formation assay as an indicator of angiogenic potential, and oxidative stress response. Results The selected clones (C18 and C26) exhibited long-term stability, rapid expansion, and preserved mesenchymal-like phenotype and multipotency. Secretome profiling revealed an enriched composition of immunoregulatory (e.g., Gal-9, IL-1Ra, TSG-6) and pro-regenerative (e.g., VEGF, PDGF-AA, EGF) factors, with enhanced responsiveness to inflammatory licensing. Notably, iHF-MSCs maintained low immunogenicity and demonstrated superior functional performance: inhibition of PBMC proliferation, Treg induction, and promotion of skin cell proliferation, migration, tube formation, and oxidative stress protection. Conclusion These results position iHF-MSCs as a robust and scalable platform for consistent production of therapeutic secretome, paving the way for innovative, cell-free immunomodulatory and regenerative therapies.

Nuria Estévez-Gómez, Tamara Prieto, Laura Tomás et al.

Summary: Single-cell genomics enables studying tissues and organisms at the highest resolution. However, since a cell contains a small amount of DNA, single-cell DNA sequencing (scDNA-seq) typically requires single-cell whole-genome amplification (scWGA). Unfortunately, scWGA methods introduce technical biases that complicate the interpretation of scDNA-seq data. We compared six scWGA methods, three MDA (multiple displacement amplification; GenomiPhi, REPLI-g, and TruePrime) and three non-MDA (Ampli1, MALBAC, and PicoPLEX), on 206 tumoral and 24 healthy human cells. scWGA methods performed differently depending on the parameter of interest. REPLI-g minimized regional amplification bias, while non-MDA methods showed a more uniform and reproducible amplification. Ampli1 exhibited the lowest allelic imbalance and dropout, the most accurate insertion or deletion (indel) and copy-number detection, and a low polymerase error rate. However, REPLI-g yielded higher DNA quantities, longer amplicons, and greater genome coverage. We offer a comprehensive guide for selecting a scWGA approach, outlining trade-offs that influence the interpretation of scDNA-seq data. Motivation: Single-cell whole-genome amplification (scWGA) is a critical step for the genomic study of single cells, yet its impact on downstream analysis remains poorly understood. Previous studies were not comprehensive in the number of methods tested and the metrics assessed. Besides, they have mostly been conducted or replicated by the original authors of a method rather than by independent third-party laboratories. Here, we test six commercially available scWGA methods to understand their performance and propose a guide for selecting the best scWGA approach for studies on single-cell genomics.

Omid Moztarzadeh, Arezou Taherpour, Avat Arman Taherpour et al.

Abstract The growing concern over antibiotic resistance necessitates novel strategies to enhance antimicrobial efficacy. This study investigates the synergistic effect of fullerene C60 on antibiotic susceptibility in Escherichia coli. In a standardized modification of the disc diffusion method, the zones of inhibition were measured on Mueller–Hinton agar with and without supplementation of fullerene C60 after incubation for 10 and 24 h, respectively. Fullerene C60 was noted for strengthening the antibacterial action of several antibiotics, especially to the extent of conversion of the bacteriostatic effect to bactericidal over a period. A statistically significant enhancement in the diameter of zones of inhibition was observed with tetracycline and co-trimoxazole, whereas amikacin and gentamicin evidenced only slight increases. The findings indicate that fullerene C60 could disrupt bacterial membrane integrity or metabolic activity, thereby potentiating the antibiotics. This paves the way for introducing nanomaterials like fullerene C60 into treatment strategies to target antibiotic resistance and bring about better therapeutic outcomes in bacterial infections.

Fengbo Zhou, Bo Wu, Jianhua Zhou

In zinc smelting solution, because the concentration of zinc is too high, the spectral signals of trace copper are masked by the spectral signals of zinc, and their spectral signals overlap, which makes it difficult to detect the concentration of trace copper. To solve this problem, a spectrophotometric method based on integrated and partition modeling is proposed. Firstly, the derivative spectra based on continuous wavelet transform are used to preprocess the spectral signal and highlight the spectral peak of copper. Then, the interval partition modeling is used to select the optimal characteristic interval of copper according to the root mean square error of prediction, and the wavelength points of the absorbance matrix are selected by correlation-coefficient threshold to improve the sensitivity and linearity of copper ions. Finally, the partial least squares integrated modeling based on the Adaboost algorithm is established by using the selected wavelength to realize the concentration detection of trace copper in the zinc liquid. Comparing the proposed method with existing regression methods, the results showed that this method can not only reduce the complexity of wavelength screening, but can also ensure the stability of detection performance. The predicted root mean square error of copper was 0.0307, the correlation coefficient was 0.9978, and the average relative error of prediction was 3.14%, which effectively realized the detection of trace copper under the background of high-concentration zinc liquid.

Clemens Steinek, Miguel Guirao-Ortiz, Gabriela Stumberger et al.

Summary: The genome contains numerous regulatory elements that may undergo complex interactions and contribute to the establishment, maintenance, and change of cellular identity. Three-dimensional genome organization can be explored with fluorescence in situ hybridization (FISH) at the single-cell level, but the detection of small genomic loci remains challenging. Here, we provide a rapid and simple protocol for the generation of bright FISH probes suited for the detection of small genomic elements. We systematically optimized probe design and synthesis, screened polymerases for their ability to incorporate dye-labeled nucleotides, and streamlined purification conditions to yield nanoscopy-compatible oligonucleotides with dyes in variable arrays (NOVA probes). With these probes, we detect genomic loci ranging from genome-wide repetitive regions down to non-repetitive loci below the kilobase scale. In conclusion, we introduce a simple workflow to generate densely labeled oligonucleotide pools that facilitate detection and nanoscopic measurements of small genomic elements in single cells. Motivation: While three-dimensional chromatin conformations can be explored with fluorescence in situ hybridization (FISH), the visualization of small genomic loci with high spatial resolution remains challenging. For such applications, programmable oligonucleotides with high brightness are required. To further improve precision and sensitivity, secondary hybridization steps should be omitted. Here, we present a simple, quick, and inexpensive approach to generate labeled FISH probes that carry several fluorophores. Our workflow allows for the free choice of fluorophores, flexible adjustment of labeling density, and selective probe synthesis from large probe pools. With our probes, we reliably detect genomic loci below the kilobase level and examine their topological relationships.

J. K.

Yuqi Wang, Wei Zhao, Linli Tan et al.

The rapid advancement of electronic communication technology has greatly aided human productivity and quality of life, but it has also resulted in significant electromagnetic pollution issues. Traditional metals and alloys are often used for electromagnetic interference (EMI) shielding due to their excellent electrical conductivity. However, they have drawbacks such as being heavy, expensive, and having low corrosion resistance, which limits their application in electromagnetic shielding. Therefore, it is crucial to develop novel EMI shielding materials. Polymers, being highly flexible, corrosion-resistant, and possessing high specific strength, are frequently employed in electromagnetic shielding materials. In this review, we firstly introduce the basic theory of electromagnetic shielding. Then, we outline the processing methods and recent developments of polymer-based electromagnetic shielding composites, including uniform-, foam-, layered-, and segregated structures. Lastly, we present the challenges and prospects for the field, aiming to provide direction and inspiration for the study of polymer-based electromagnetic shielding composite materials.

Mariuca Gartner, Hermine Stroescu, Daiana Mitrea et al.

This review addresses the importance of Zn for obtaining multifunctional materials with interesting properties by following certain preparation strategies: choosing the appropriate synthesis route, doping and co-doping of ZnO films to achieve conductive oxide materials with p- or n-type conductivity, and finally adding polymers in the oxide systems for piezoelectricity enhancement. We mainly followed the results of studies of the last ten years through chemical routes, especially by sol-gel and hydrothermal synthesis. Zinc is an essential element that has a special importance for developing multifunctional materials with various applications. ZnO can be used for the deposition of thin films or for obtaining mixed layers by combining ZnO with other oxides (ZnO-SnO₂, ZnO-CuO). Also, composite films can be achieved by mixing ZnO with polymers. It can be doped with metals (Li, Na, Mg, Al) or non-metals (B, N, P). Zn is easily incorporated in a matrix and therefore it can be used as a dopant for other oxidic materials, such as: ITO, CuO, BiFeO_3, and NiO. ZnO can be very useful as a seed layer, for good adherence of the main layer to the substrate, generating nucleation sites for nanowires growth. Thanks to its interesting properties, ZnO is a material with multiple applications in various fields: sensing technology, piezoelectric devices, transparent conductive oxides, solar cells, and photoluminescence applications. Its versatility is the main message of this review.

Engin Aşlar

Thermal quenching is described as a decrease in luminescence efficiency with increasing measurement temperature. Luminescence intensity decreases with increasing heating rates in the presence of thermal quenching. In such a case, the heating rate to be used in the measurements becomes important. Lithium fluoride (LiF) type dosimeters have been widely used in radiation dosimetry for many years. In this study, thermal quenching effect was investigated for LiF:Mg,Ti (TLD-100) and LiF:Mg,Cu,P (TLD-100H), 6LiF:Mg,Ti(TLD-600) and 7LiF:Mg,Ti (TLD-700) at two different doses (10, 1000mGy) using 90Sr/90Y beta source. TLD-100, TLD-600 and TLD-700 showed different thermal quenching behaviors according to dose values, while TLD-100H had the same characteristics at both doses. On the other hand, other dosimeters showed thermal quenching based on the total area at 10mGy, while they did not show thermal quenching when ROI was used. Again, thermal quenching was not observed at 1000mGy for all dosimeters. In conclusion, it is recommended to use ROI or low heating rate during measurements at a low dose (in the order of mGy) for TLD-100, TLD-600 and TLD-700, while desired heating rate can be used at a high dose (Gy) for all dosimeters.

Harshita Gaurav, Divyanshu Yadav, Ankita Maurya et al.

<i>Withania somnifera</i> L. Dunal (Ashwagandha), a key medicinal plant native to India, is used globally to manage various ailments. This review focuses on the traditional uses, botany, phytochemistry, and pharmacological advances of its plant-derived constituents. It has been reported that at least 62 crucial and 48 inferior primary and secondary metabolites are present in the <i>W. somnifera</i> leaves, and 29 among these found in its roots and leaves are chiefly steroidal compounds, steroidal lactones, alkaloids, amino acids, etc. In addition, the whole shrub parts possess various medicinal activities such as anti-leukotriene, antineoplastic, analgesic, anti-oxidant, immunostimulatory, and rejuvenating properties, mainly observed by in vitro demonstration. However, the course of its medical use remains unknown. This review provides a comprehensive understanding of <i>W. somnifera</i>, which will be useful for mechanism studies and potential medical applications of <i>W. somnifera</i>, as well as for the development of a rational quality control system for <i>W. somnifera</i> as a therapeutic material in the future.

Vincenzo Tragni, Guido Primiano, Albina Tummolo et al.

Mitochondrial diseases (MDs) may result from mutations affecting nuclear or mitochondrial genes, encoding mitochondrial proteins, or non-protein-coding mitochondrial RNA. Despite the great variability of affected genes, in the most severe cases, a neuromuscular and neurodegenerative phenotype is observed, and no specific therapy exists for a complete recovery from the disease. The most used treatments are symptomatic and based on the administration of antioxidant cocktails combined with antiepileptic/antipsychotic drugs and supportive therapy for multiorgan involvement. Nevertheless, the real utility of antioxidant cocktail treatments for patients affected by MDs still needs to be scientifically demonstrated. Unfortunately, clinical trials for antioxidant therapies using α-tocopherol, ascorbate, glutathione, riboflavin, niacin, acetyl-carnitine and coenzyme Q have met a limited success. Indeed, it would be expected that the employed antioxidants can only be effective if they are able to target the specific mechanism, i.e., involving the central and peripheral nervous system, responsible for the clinical manifestations of the disease. Noteworthily, very often the phenotypes characterizing MD patients are associated with mutations in proteins whose function does not depend on specific cofactors. Conversely, the administration of the antioxidant cocktails might determine the suppression of endogenous oxidants resulting in deleterious effects on cell viability and/or toxicity for patients. In order to avoid toxicity effects and before administering the antioxidant therapy, it might be useful to ascertain the blood serum levels of antioxidants and cofactors to be administered in MD patients. It would be also worthwhile to check the localization of mutations affecting proteins whose function should depend (less or more directly) on the cofactors to be administered, for estimating the real need and predicting the success of the proposed cofactor/antioxidant-based therapy.

Gerson Lopes Teixeira, Elena Ibañez, Jane Mara Block

Arecaceae palm tree fruits (APTFs) with pulp or kernel rich in oil are widely distributed in six Brazilian biomes. APTFs represent a great potential for the sustainable exploitation of products with high added value, but few literature studies have reported their properties and industrial applications. The lack of information leads to underutilization, low consumption, commercialization, and processing of these fruit species. This review presents and discusses the occurrence of 13 APTFs and the composition, physicochemical properties, bioactive compounds, and potential applications of their 25 oils and fats. The reported studies showed that the species present different lipid profiles. Multivariate analysis based on principal component analysis (PCA) and hierarchical cluster analysis (HCA) indicated a correlation between the composition of pulp and kernel oils. Myristic, caprylic, capric, and lauric acids are the main saturated fatty acids, while oleic acid is the main unsaturated. Carotenoids and phenolic compounds are the main bioactive compounds in APTFs, contributing to their high oxidative stability. The APTFs oils have a potential for use as foods and ingredients in the cosmetic, pharmaceutical, and biofuel industries. However, more studies are still necessary to better understand and exploit these species.

E. W. Garbisch

Zemene Demelash Kifle, Agumas Alemu Alehegn, Meaza Adugna et al.

Background: Serum lipid profile abnormalities are major predictors for coronary artery diseases. The relationship between demographic factors and dyslipidemia in Ethiopia is not completely explored. Thus, this study aimed to assess the prevalence and predictors of dyslipidemia among hypertensive patients in Lumame Primary Hospital. Methods: A cross-sectional study was conducted from June to August 30, 2020, on the hypertensive patients in Lumame Primary Hospital. All adult hypertensive patients who visited the adult hypertensive care services during the study period were included. Interview-guided self-administered questionnaire and a chart review were used for data collection. Statistical Package for the Social Sciences (SPSS) software version 24.0 was used for data analysis. Results: Out of 372 hypertensive patients, 190(51.1%) were females and the mean age of the study participants was 43.56 years (SD ± 4.31). The overall prevalence of dyslipidemia in this study was 48.4%. Besides the overall prevalence, the prevalence of TC, TG, LDL-c, and HDL-c was 73(19.6%), 91(24.5%), 60(16.1%), and 115(30.9%), respectively. Females were at higher risk for having high levels of TC (AOR = 2.31, 95% CI = 1.54–3.13), TG (AOR = 1.70, 95% CI = 1.34–3.79), LDL-c (AOR = 2.15, 95% CI = 1.56–2.86), and HDL-c (AOR = 2.67, 95% CI = 1.44–5.67) than males. Respondents who were from urban were at higher risk for having high levels of TC (AOR = 1.98, 95% CI = 1.04–6.83), TG (AOR = 1.78, 95% CI = 1.09–2.86), LDL-c (AOR = 3.01, 95% CI = 1.45–7.43), and HDL-c (AOR = 2.01, 95% CI = 1.94–4.55) than respondents who were from rural. Similarly, obese respondents were at higher risk for having high levels of TC (AOR = 2.03, 95% CI = 1.64–2.00), TG (AOR = 3.78, 95% CI = 1.06–6.42), LDL-c (AOR = 1.92, 95% CI = 1.66–2.12), and HDL-c (AOR = 4.23, 95% CI = 2.84–4.32) than to respondents who were underweight. Conclusion: The prevalence of dyslipidemia among hypertensive patients was high. Independent variables such as age, gender, residence, family history of HTN, smoking, alcohol drinking, fruit diet habits, physical activity, DM, and BMI were significant determinants of dyslipidemia.

John D. Roberts