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1.
ChemSusChem ; : e202401694, 2024 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-39370406

RESUMEN

Hydrogen has received enormous attention as a clean fuel with its high specific energy (142 MJ/kg). To apply hydrogen as a practically available energy vector, the direct production of high-pressure hydrogen with high purity is pivotal, as it allows for circumventing the mechanical compression process. Recently, the concept of utilizing sodium borohydride (SBH) dehydrogenation as a chemical compressor that can generate high-pressure hydrogen gas was demonstrated by adopting formic acid as an acid catalyst. However, the presence of impurities (e.g., CO, CO2) in the final gas product requires an alternative method to enhance the use of SBH as a chemical compressor. Here, we highlighted the feasibility of producing high-purity, high-pressure hydrogen gas from the SBH dehydrogenation with and without Co-based catalysts. The scrutiny behind the thermodynamics and kinetics of the SBH dehydrogenation was conducted under the elevated pressure condition. As a result, the dual roles of the catalysts as proton collectors and heat sources were revealed, both of which are essential for improving hydrogen production efficiency. We hope that our research stimulates subsequent research that pave the way to exploit hydrogen as an energy vector and achieve a more sustainable future society.

2.
Bioresour Technol ; : 131553, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39362347

RESUMEN

Worsening environmental conditions make lactic acid a sustainable alternative to petroleum-based plastics. This study created a genetically-engineered strain Lactiplantibacillus pentosus PeL containing a disrupted L-lactate dehydrogenase gene to produce high yield and optically pure D-lactic acid. Cellobiose was identified as the optimal sugar in the single carbon source test, yielding the highest lactic acid. In 5-L fermentation tests, pretreated wood chips hydrolysate was the best lignocellulosic substrate for PeL, resulting in a D-lactic acid yield of 900.7 ±â€¯141.4 mg/g of consumed sugars with an optical purity of 99.8 ±â€¯0.0 %. Gradually scaled-up fermentations using this substrate were achieved in 100-, and 9,000-L fermenters; PeL produced remarkably high D-lactic acid yields of 836.3 ±â€¯11.9 and 915.9 ±â€¯4.4 mg/g of consumed sugars, with optical purities of 95.0 ±â€¯0.0 % and 93.8 ±â€¯0.2 %, respectively. This study is the pioneer in demonstrating economical and sustainable ton-scale production of D-lactic acid.

3.
Bioresour Technol ; 414: 131578, 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39384045

RESUMEN

The fermentation of polymalic acid (PMA) by Aureobasidium pullulans, followed by acid hydrolysis to release the monomer l-malic acid (l-MA), has emerged as a promising process for the bio-based production of l-MA. However, the presence of specific by-products significantly affects the quality of the final products. In this study, chassis strains harboring an overexpressed endogenous malate dehydrogenase gene (ApMDH2) were engineered to delete key genes involved in the pullulan, melanin, and liamocin biosynthetic pathways. Furthermore, to enhance PMA synthesis productivity and prevent intracellular NADPH accumulation, an irreversible trans-hydrogenase transformation system was designed to efficiently convert NADPH to NADH. In fed-batch fermentation, the engineered strain produced the highest PMA titer (194.3 ± 1.1 g/L) and l-MA yield (0.89 ± 0.01 g/g) with an increased productivity (1.45 ± 0.06 g/L∙h). Moreover, a total of 86.19 % l-MA, with a purity of 99.7 %, was successfully extracted from fermentation broth.

4.
Polymers (Basel) ; 16(19)2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39408501

RESUMEN

Brewer's spent grains (BSG) offer valuable opportunities for valorization beyond its conventional use as animal feed. Among its components, lignin-a natural polymer with inherent antioxidant properties-holds significant industrial potential. This work investigates the use of microwave-assisted extraction combined with acidic natural deep eutectic solvents (NaDESs) for efficient lignin recovery, evaluating three different NaDES formulations. The results indicate that choline chloride-lactic acid (ChCl-LA), a NaDES with superior thermal stability as confirmed via thermogravimetric analysis (TGA), is an ideal solvent for lignin extraction at 150 °C and 15 min, achieving a balance of high yield and quality. ChCl-LA also demonstrated good solubility and cell disruption capabilities, while microwaves significantly reduced processing time and severity. Under optimal conditions, i.e., 150 °C, 15 min, in the presence of ChCl-LA NaDES, the extracted lignin achieved a purity of up to 79% and demonstrated an IC50 (inhibitory concentration 50%) of approximately 0.022 mg/L, indicating a relatively strong antioxidant activity. Fourier transform infrared (FTIR) and 2D-HSQC NMR (heteronuclear single quantum coherence nuclear magnetic resonance) spectroscopy confirmed the successful isolation and preservation of its structural integrity. This study highlights the potential of BSG as a valuable lignocellulosic resource and underscores the effectiveness of acidic NaDESs combined with microwave extraction for lignin recovery.

5.
Regen Biomater ; 11: rbae095, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39346687

RESUMEN

With mechanical strength close to cortical bone, biodegradable and osteopromotive properties, magnesium (Mg)-based implants are promising biomaterials for orthopedic applications. However, during the degradation of such implants, there are still concerns on the potential adverse effects such as formation of cavities, osteolytic phenomena and chronic inflammation. Therefore, to transform Mg-based implants into clinical practice, the present study evaluated the local effects of high-purity Mg screws (HP-Mg, 99.99 wt%) by comparing with clinically approved polylactic acid (PLA) screws in epiphyseal trabecular bone of rabbits. After implantation of screws at the rabbit distal femur, bone microstructural, histomorphometric and biomechanical properties were measured at various time points (weeks 4, 8 and 16) using micro-CT, histology and histomorphometry, micro-indentation and scanning electron microscope. HP-Mg screws promoted peri-implant bone ingrowth with higher bone mass (BV/TV at week 4: 0.189 ± 0.022 in PLA group versus 0.313 ± 0.053 in Mg group), higher biomechanical properties (hardness at week 4: 35.045 ± 1.000 HV in PLA group versus 51.975 ± 2.565 HV in Mg group), more mature osteocyte LCN architecture, accelerated bone remodeling process and alleviated immunoreactive score (IRS of Ram11 at week 4: 5.8 ± 0.712 in PLA group versus 3.75 ± 0.866 in Mg group) as compared to PLA screws. Furthermore, we conducted finite element analysis to validate the superiority of HP-Mg screws as orthopedic implants by demonstrating reduced stress concentration and uniform stress distribution around the bone tunnel, which led to lower risks of trabecular microfractures. In conclusion, HP-Mg screws demonstrated greater osteogenic bioactivity and limited inflammatory response compared to PLA screws in the epiphyseal trabecular bone of rabbits. Our findings have paved a promising way for the clinical application of Mg-based implants.

6.
Regen Ther ; 26: 749-759, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-39290629

RESUMEN

Introduction: Neural crest cells (NCCs) are cell populations that originate during the formation of neural crest in developmental stages. They are characterized by their multipotency, self-renewal and migration potential. Given their ability to differentiate into various types of cells such as neurons and Schwann cells, NCCs hold promise for cell therapy applications. The conventional method for obtaining NCCs involves inducing them from stem cells like induced pluripotent stem cells (iPSCs), followed by a long-term passage or purification using fluorescence-activated cell sorting (FACS). Although FACS allows high purity induced neural crest cells (iNCCs) to be obtained quickly, it is complex and costly. Therefore, there is a need for a simpler, cost-effective and less time-consuming method for cell therapy application. Methods: To select differentiated iNCCs from heterogeneous cell populations quickly without using FACS, we adopted the use of scaffold material full-length laminin 211 (LN211), a recombinant, xeno-free protein suitable for cell therapy. After fist passage on LN211, iNCCs characterization was performed using polymerase chain reaction and flow cytometry. Additionally, proliferation and multipotency to various cells were evaluated. Result: The iNCCs obtained using our new method expressed cranial NCC- related genes and exhibited stable proliferation ability for at least 57 days, while maintaining high expression level of the NCCs marker CD271. They demonstrated differentiation ability into several cell types: neurons, astrocytes, melanocytes, smooth muscle cells, osteoblasts, adipocytes and chondrocytes. Furthermore, they could be induced to differentiate into induced mesenchymal stem cells (iMSCs) which retain the essential functions of somatic MSCs. Conclusion: In this study, we have developed novel method for obtaining high purity iNCCs differentiated from iPSCs in a short time using LN211 under xeno-free condition. Compared with traditional methods, like FACS or long-term passage, this approach enables the acquisition of a large amount of cells at a lower cost and labor, and it is expected to contribute to stable supply of large scale iNCCs for future cell therapy applications.

7.
Anal Chim Acta ; 1325: 343135, 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39244297

RESUMEN

BACKGROUND: Mass spectrometry (MS)-based proteomics is a powerful tool for identifying and quantifying proteins. However, chimeric spectra caused by the fragmentation of multiple precursors within the same isolation window impair the accuracy of peptide identification and isobaric mass tag-based quantification. While there have been advances in computational deconvolution of chimeric spectra and methods to further separate the peptides by ion mobility or through MSn, the use of narrower isolation windows to decrease the fraction of chimeric species remains to be fully explored. RESULTS: We present results obtained on a SCIEX TripleTOF instrument where the quadrupole was optimized and tuned for precursor isolation at 0.1 Da (FWHH). Using a three-proteome model (trypsin digest of protein lysates from yeast, human and E. coli) and 8-plex iTRAQ labeling to document the interference effect, we investigated the impact of co-fragmentation on spectral purity, identification accuracy and quantification accuracy. The narrow quadrupole isolation window significantly improved the spectral purity and reduced the interference of non-target precursors on quantification accuracy. The high-resolution isolation strategy also reduced the number of false identifications caused by chimeric spectra. While these improvements came at the cost of sensitivity loss, combining high-resolution isolation with other advanced techniques, including ion mobility, may result in improved accuracy in identification and quantification. SIGNIFICANCE: Compared to standard-resolution quadrupole isolation (0.7 Da), high-resolution quadrupole isolation (0.1 Da) significantly improved the spectral purity and quantification accuracy while reducing the number of potential false identifications caused by chimeric spectra, thus showing excellent potential for further development to analyze clinical proteomics samples, for which high accuracy is essential.


Asunto(s)
Proteómica , Proteómica/métodos , Humanos , Iones/química , Escherichia coli/química , Saccharomyces cerevisiae/química , Péptidos/química , Péptidos/análisis , Espectrometría de Masas/métodos
8.
Nano Lett ; 24(37): 11599-11606, 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39229905

RESUMEN

2D layered metal halide perovskites (MHPs) are a potential material for fabricating self-powered photodetectors (PDs). Nevertheless, 2D MHPs produced via solution techniques frequently exhibit multiple quantum wells, leading to notable degradation in the device performance. Besides, the wide band gap in 2D perovskites limits their potential for broad-band photodetection. Integrating narrow-band gap materials with perovskite matrices is a viable strategy for broad-band PDs. In this study, the use of methylamine acetate (MAAc) as an additive in 2D perovskite precursors can effectively control the width of the quantum wells (QWs). The amount of MAAc greatly affects the phase purity. Subsequently, PbSe QDs were embedded into the 2D perovskite matrix with a broadened absorption spectrum and no negative effects on ferroelectric properties. PM6:Y6 was combined with the hybrid ferroelectric perovskite films to create a self-powered and broad-band PD with enhanced performance due to a ferro-pyro-phototronic effect, reaching a peak responsivity of 2.4 A W-1 at 940 nm.

9.
Int J Biol Macromol ; 280(Pt 4): 135936, 2024 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-39322130

RESUMEN

Lignin is a complex biopolymer whose efficient extraction from biomass is crucial for various applications. Deep eutectic solvents (DES), particularly natural-origin DES (NADES), have emerged as promising systems for lignin fractionation and separation from other biomass components. While ternary DES offer enhanced fractionation performance, the role of each component in these mixtures remains unclear. In this study, the effects of adding tartaric acid (Tart) or citric acid (Cit) to a common binary DES mixture composed of lactic acid (Lact) and choline chloride (ChCl) were investigated for lignin extraction from acacia wood. Ternary Cit-based DES showed superior performance compared to Tart-based DES. Using a combined mixture-process D-Optimal experimental design, the Lact:Cit:ChCl DES composition and extraction temperature were optimized targeting maximum lignin yield and purity. The optimal conditions (i.e., Lact:Cit:ChCl, 0.6:0.3:0.1 molar ratio, 140 °C) resulted in a lignin extraction yield of 99.63 ± 1.24 % and a lignin purity of 91.45 ± 1.03 %. Furthermore, this DES exhibited feasible recyclability and reusability without sacrificing efficiency.

10.
Chemosphere ; 365: 143335, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39277042

RESUMEN

This study aimed to recover high-purity silica from hematite tailings (HTs) using superconducting high-gradient magnetic separation (S-HGMS) technology. This process involved converting silica into a silicone-rich concentrate and subsequently employing a fluorine-free mixed acid to leach the silicon-rich concentrate to remove impurities and achieve refinement and purification. The optimization of the S-HGMS process was conducted using the "Box-Behnken Design" method, resulting in the following optimal conditions: a pulp concentration of 50 g/L, a magnetic velocity ratio of 0.076 T s/m, and a pulp velocity of 500 mL/min. These conditions yielded a silica grade range of 61.905% in the HTs to 91.818% in the silicon-rich concentrate, with corresponding recovery rates of 53.031%. Under the optimized leaching process, this resulted in an increase in the silica content from 91.818% in the silicon-rich concentrate to 99.938% in high-purity silica. Additionally, by analyzing the production process of 1 kg of high-purity silica from HTs using the process LCA method, environmental hotspots were identified, and corresponding solutions were proposed. This approach is vital for efficient utilization of HTs as a resource. This process has low energy consumption and is environmentally friendly, enabling the reduction of hematite tailings. It has a wide range of applications and offers substantial economic benefits, rendering it a promising candidate for industrial applications.


Asunto(s)
Compuestos Férricos , Dióxido de Silicio , Dióxido de Silicio/química , Compuestos Férricos/química
11.
J Pharmacol Toxicol Methods ; 129: 107549, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39236994

RESUMEN

Ribonucleic acid (RNA) extraction and purification play pivotal roles in molecular biology and cell and gene therapy, where the quality and integrity of RNA are critical for downstream applications. Automated high-throughput systems have gained interest due to their potential for scalability and reduced labor requirements compared to manual methods. However, ensuring high-throughput capabilities, reproducibility, and reliability while maintaining RNA yield and purity remains challenging. This study evaluated and compared the performance of four commercially available high-throughput magnetic bead-based RNA extraction kits across six types of naïve non-human primate (NHP) tissue matrices: brain, heart, kidney, liver, lung, and spleen. The assessment focused on RNA purity, yield, and extraction efficiency (EE) using Xeno Internal Positive Control (IPC) spiking. Samples (∼50 mg) were homogenized via bead-beating and processed according to the manufacturer's protocol on the KingFisher Flex platform in eight replicates. RNA purity and yield were measured using a NanoDrop® spectrophotometer, while EE was evaluated via real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The findings indicate consistent high RNA purity across all tested extraction kits, yet substantial variation in RNA yield. Extraction efficiency exhibited variations across tissue types, with decreasing trends observed from brain to lung tissues. These results underscore the importance of careful kit selection and method optimization for achieving reliable downstream applications. The MagMAX™ mirVana™ Total RNA Isolation Kit stands out as the most accurate and reproducible, making it the preferred choice for applications requiring high RNA quality and consistency. Other kits, such as the Maxwell® HT simplyRNA Kit, offer a good balance between cost and performance, though with some trade-offs in precision. These findings highlight the importance of selecting the appropriate RNA isolation method based on the specific needs of the research, underscoring the critical role of accurate nucleic acid extraction in gene and cell therapy research. In conclusion, this study highlights the critical factors influencing RNA extraction performance, emphasizing the need for researchers and practitioners to consider both kit performance and tissue characteristics when designing experimental protocols. These insights contribute to the ongoing efforts to enhance the reproducibility and reliability of RNA extraction methods in molecular biology and cell/gene therapy applications.


Asunto(s)
ARN , Animales , ARN/aislamiento & purificación , ARN/genética , Reproducibilidad de los Resultados , Ensayos Analíticos de Alto Rendimiento/métodos , Pulmón/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Encéfalo/metabolismo , Hígado/metabolismo , Bazo/metabolismo , Juego de Reactivos para Diagnóstico/normas
12.
Molecules ; 29(16)2024 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-39202888

RESUMEN

The efficiency and reproducibility of perovskite solar cells (PSCs) are significantly influenced by the purity of lead iodide (PbI2) in the raw materials used. Pb(OH)I has been identified as the primary impurity generated from PbI2 in water-based synthesis. Consequently, a comprehensive investigation into the impact of Pb(OH)I impurities on film and device performance is essential. In this study, PbI2, with varying stoichiometries, was synthesized to examine the effects of different Pb(OH)I levels on perovskite device performance. The characterization results revealed that even trace amounts of Pb(OH)I impede the formation of precursor prenucleation clusters. These impurities also increase the energy barrier of the α-phase and facilitate the transition of the intermediate phase to the δ-phase. These effects result in poor perovskite film morphology and sub-optimal photovoltaic device performance. To address these issues, a cost-effective method for preparing high-stoichiometry PbI2 was developed. The formation of Pb(OH)I was effectively inhibited through several strategies: adjusting solution pH and temperature, modifying material addition order, simplifying the precipitation-recrystallization process, and introducing H3PO2 as an additive. These modifications enabled the one-step synthesis of high-purity PbI2. PSCs prepared using this newly synthesized high-stoichiometry PbI2 demonstrated photovoltaic performance comparable to those fabricated with commercial PbI2 (purity ≥ 99.999%). Our novel method offers a cost-effective alternative for synthesizing high-stoichiometry PbI2, thereby providing a viable option for the production of high-performance PSCs.

13.
N Biotechnol ; 83: 155-162, 2024 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-39128541

RESUMEN

Within the circular bioeconomy the production of optically pure LA from 2nd generation feedstocks would be ideal but it is very challenging. In this paper genetically engineered Escherichia coli strains were created to resolve racemic LA solutions synthesised and produced from the fermentation of organic waste or ensiled grass. Refining LA racemic mixtures into either a D- or L-LA was achieved by cells being able to consume one LA isomer as a sole carbon and energy source while not being able to consume the other. A D-LA refining strain JSP0005 was grown on fermented source-sorted organic household waste and different grass silage leachates, which are 2nd generation feedstocks containing up to 33 g/L lactic acid racemate. In all growth experiments, L-LA was completely removed leaving D-LA as the only LA stereoisomer, i.e. resulting in optically pure D-LA, which also increased by as much as 248.6 % from its starting concentration, corresponding to 38 g/L. The strains resulting from this study are a promising first step towards a microbial based LA biorefining process.


Asunto(s)
Escherichia coli , Fermentación , Ácido Láctico , Escherichia coli/metabolismo , Ácido Láctico/metabolismo , Ácido Láctico/biosíntesis
14.
J Pharm Biomed Anal ; 251: 116390, 2024 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-39190935

RESUMEN

This study introduces a new NMR-based methodology for identification (ID) and quantification (purity, strength) assays of widely used amino acids. A detailed analysis of four amino acids and their available salts was performed with both a high-field (600 MHz) and a benchtop (60 MHz) NMR instrument. To assess sensitivity constraints, samples for 1H NMR analysis were initially prepared using only 10 mg of analyte and 1 mg of maleic acid (MA) as an internal calibrant (IC) and secondary chemical shift reference. The characteristic dispersion of the peak patterns indicating the presence or absence of a counterion (mostly chloride) was conserved at both high and low-field strength instruments, showing that the underlying NMR spectroscopic parameters, i.e., chemical shifts and coupling constants, are independent of the magnetic field strength. However, as the verbal descriptions of 1H NMR spectra are challenging in the context of reference materials and pharmaceutical monographs, an alternative method for the identification (ID) of amino acids is proposed that uses 13C NMR patterns from multiplicity-edited HSQC (ed-HSQC), which are both compound-specific and straightforward to document. For ed-HSQC measurements, the sample amount was increased to 30 mg of the analyte and several acquisition parameters were tested, including t1 increments used in the pulse program, number of scans, and repetition time. Excellent congruence with deviations <0.1 ppm was achieved for the 13C chemical shifts from 1D 13C NMR spectra (150 MHz) vs. those extracted from ed-HSQC (15 MHz traces). Finally, all samples of amino acid candidate reference materials were quantified by 1H qNMR (abs-qHNMR) at both 600 and 60 MHz. At high field, both IC and relative quantitations were performed, however, with the low-field instrument, only the IC method was used. The results showed that the analyzed reference material candidates were generally highly pure compounds. To achieve adequately low levels of uncertainty for such high-purity materials, the sample amounts were increased to 100 mg of analytes and 10 mg of the IC and replicates were analyzed for selected amino acids.


Asunto(s)
Aminoácidos , Espectroscopía de Resonancia Magnética , Aminoácidos/análisis , Aminoácidos/química , Espectroscopía de Resonancia Magnética/métodos , Estándares de Referencia , Calibración , Espectroscopía de Protones por Resonancia Magnética/métodos , Maleatos/química , Maleatos/análisis
15.
Heliyon ; 10(14): e33941, 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39108897

RESUMEN

In the grain industry, identifying seed purity is a crucial task because it is an important factor in evaluating seed quality. For rice seeds, this attribute enables the minimization of unexpected influences of other varieties on rice yield, nutrient composition, and price. However, in practice, they are often mixed with seeds from other varieties. This study proposes a novel method for automatically identifying the purity of a specific rice variety using hybrid machine learning algorithms. The core concept involves leveraging deep learning architectures to extract pertinent features from raw data, followed by the application of machine learning algorithms for classification. Several experiments are conducted to evaluate the performance of the proposed model through practical implementation. The results demonstrate that the novel method substantially outperformed the existing methods, demonstrating the potential for effective rice seed purity identification systems.

16.
J Proteome Res ; 23(9): 3933-3943, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39140748

RESUMEN

Immunoglobulin G (IgG) purification is a critical process for evaluating its role in autoimmune diseases, which are defined by the occurrence of autoantibodies. Affinity chromatography with protein G is widely considered to be the optimal technique for laboratory-scale purification. However, this technique has some limitations, including the exposure of IgG to low pH, which can compromise the quality of the purified IgG. Here, we show that alternative methods for IgG purification are possible while maintaining the quality of IgG. Different techniques for IgG purification from serum were evaluated and compared with protein G-based approaches: Melon Gel, caprylic acid-ammonium sulfate (CAAS) precipitation, anion-exchange chromatography with diethylamino ethyl (DEAE) following ammonium sulfate (AS) precipitation, and AS precipitation alone. The results demonstrated that the purification yield of these techniques surpassed that of protein G. However, differences in the purity of IgG were observed using GeLC-MS/MS. The avidity of purified IgG against selected targets (SARS-CoV-2 and topoisomerase-I) was similar between purified IgG obtained using all techniques and unpurified sera. Our work provides valuable insights for future studies of IgG function by recommending alternative purification methods that offer advantages in terms of yield, time efficiency, cost-effectiveness, and milder pH conditions than protein G.


Asunto(s)
Sulfato de Amonio , Cromatografía de Afinidad , Inmunoglobulina G , Humanos , Inmunoglobulina G/aislamiento & purificación , Inmunoglobulina G/sangre , Inmunoglobulina G/química , Cromatografía de Afinidad/métodos , Sulfato de Amonio/química , Cromatografía por Intercambio Iónico/métodos , Espectrometría de Masas en Tándem/métodos , SARS-CoV-2/inmunología , Caprilatos/química , Precipitación Química , COVID-19/sangre , COVID-19/inmunología , COVID-19/virología , Afinidad de Anticuerpos
17.
Anal Bioanal Chem ; 416(23): 5177-5189, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39117955

RESUMEN

D-Phenylalanine (D-Phe) is a small chiral organic molecule that is both an important pharmaceutical intermediate and used as a calibrator for quantifying amino acids in liquid chromatography-circular dichroism. We have developed a process for a national certified reference material (CRM) for D-Phe following ISO 17034:2016. The identity of D-Phe was confirmed using mass spectrometry (MS) and nuclear magnetic resonance (NMR), infrared, and ultraviolet (UV) spectroscopy. The absolute optical conformation was also determined using circular dichroism (CD) spectroscopy and optical rotation measurements. Impurities were identified via liquid chromatography (LC) with a UV-Vis detector and a charged aerosol detector (CAD) and LC-MS. Both mass balance and quantitative NMR were employed for value assessment, and the associated uncertainty was evaluated. The certified purity was determined to be 0.995 ± 0.003 g/g, a validation that was confirmed by CD using L-Phe CRM as a calibrator. Twenty milligrams of raw material was packed in sealed brown glass tubes for storage, and no inhomogeneity was observed. Stability tests revealed that the D-Phe CRM remained stable at -20 °C for at least 26 months, at 4 °C for at least 14 days, and at 25 °C and 60 °C for at least 7 days. The D-Phe CRM can be used to ensure the accuracy and reliability of D-Phe quantitation in the pharmaceutical field and also as a calibrator to ensure traceability to the International System of Units (SI) for L-Phe quantitation and protein purity analysis using LC-CD methods. The approach outlined in this paper also has potential for use in the development of other chiral CRMs.


Asunto(s)
Fenilalanina , Estándares de Referencia , Fenilalanina/análisis , Fenilalanina/química , Estereoisomerismo , Dicroismo Circular , Cromatografía Liquida/métodos , Espectroscopía de Resonancia Magnética/métodos , Espectrometría de Masas/métodos , Calibración
18.
ACS Nano ; 18(34): 23392-23402, 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39140886

RESUMEN

Semiconducting carbon nanotubes (s-CNTs) have emerged as a promising alternative to traditional silicon for ultrascaled field-effect transistors (FETs), owing to their exceptional properties. Aligned s-CNTs (A-CNTs) are particularly favored for practical applications due to their ability to provide higher driving current and lower contact resistance compared with individual s-CNTs or random networks. Achieving high-semiconducting-purity A-CNTs typically involves conjugated polymer wrapping for selective separation of s-CNTs, followed by self-assembly techniques. However, the presence of the polymer wrapper on A-CNTs can adversely impact electrical contact, gating efficiency, carrier transport, and device-to-device variations, necessitating its complete removal. While various methods have been explored for polymer removal, accurately characterizing the extent of removal remains a challenge. Traditional techniques such as absorption spectroscopy and X-ray photoelectron spectroscopy (XPS) may not accurately depict the remaining polymer content on A-CNTs due to their inherent detection limits. Consequently, the performance of FETs based on pure polymer-wrapper-free A-CNTs is unclear. In this study, we present an approach for preparing high-semiconducting-purity and polymer-wrapper-free A-CNTs using poly[(9,9-dioctylfluorenyl-2,7-dinitrilomethine)-(9,9-dioctylfluorenyl-2,7-dimethine)] (PFO-N-PFO), a degradable polymer, in conjunction with a modified dimension-limited self-alignment process (m-DLSA). Comprehensive transmission electron microscopy (TEM) characterizations, complemented by absorption and XPS characterizations, provide robust evidence of the successful near-complete removal of the polymer wrapper via a cleaning procedure involving acidic degradation, hot solvent rinsing, and vacuum annealing. Furthermore, top-gated FETs based on these high-semiconducting-purity and polymer-wrapper-free A-CNTs exhibit good performance metrics, including an on-current (Ion) of 2.2 mA/µm, peak transconductance (gm) of 1.1 mS/µm, low contact resistance (Rc) of 191 Ω·µm, and negligible hysteresis, representing a significant advancement in the CNT-based FET technology.

19.
Luminescence ; 39(7): e4810, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38965929

RESUMEN

Four eight-coordinated luminescent samarium complexes of type [Sm(hfpd)3L2] and [Sm(hfpd)3L'] [where hfpd = 1,1,1,5,5,5-Hexafluoro-2,4-pentanedione L = tri-octyl-phosphine oxide (TOPO) and L' = 1,10-phenanthroline (phen), neocuproine (neoc) and bathocuproine (bathoc) were synthesized via a stoichiometrically controlled approach. This allows for precise control over the stoichiometry of the complexes, leading to reproducible properties. This investigation focuses on understanding the impact of secondary ligands on the luminescent properties of these complexes. Infrared (IR) spectra provided information about the molecular structures, whereas 1H and 13C nuclear magnetic resonance (NMR) spectra confirmed these structural details along with the coordination of ligands to trivalent Sm ion. The UV-vis spectra revealed the molar absorption coefficient and absorption bands associated with the hfpd ligand and photoluminescence (PL) spectroscopy demonstrated intense orange-red emission (648 nm relative to 4G5/2 → 6H9/2) from the complexes. The Commission Internationale de l'Éclairage (CIE) triangles indicated that the complexes emitted warm orange red light with color coordinates (x, y) ranging from (0.62, 0.36) to (0.40, 0.27). The investigation of the band gap as well as color parameters confirms the utility of these complexes in displays and LEDs.


Asunto(s)
Luminiscencia , Samario , Ligandos , Samario/química , Estructura Molecular , Complejos de Coordinación/química , Complejos de Coordinación/síntesis química , Pentanonas/química , Sustancias Luminiscentes/química , Sustancias Luminiscentes/síntesis química , Mediciones Luminiscentes
20.
J Dairy Sci ; 2024 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-39033914

RESUMEN

Increasing studies have highlighted the significance of milk-derived extracellular vesicles (MEVs) in mother-newborn integration, as well as their application as novel drug delivery systems and diagnostic biomarkers. However, conventional ultracentrifugation (UC) often results in the co-precipitation of casein micelles in MEV pellets. In this study, we compared methods with different principles to screen the optimal pretreatment in caseins removal, and found that isoelectric precipitation by hydrochloric acid (HA) could most effectively remove caseins in porcine milk. We further characterized MEV populations isolated by UC and HA/UC from diverse aspects, including particle methodology via nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM), RNA and protein contents, and purity analysis. Importantly, the proliferative and anti-inflammatory effects of MEVs were evaluated in vitro, showing the superiority of MEVs via HA/UC in functionality compared with UC. Our results suggest that HA pretreatment before ultracentrifugation could effectively remove caseins and other protein complexes, leading to MEVs via HA/UC with higher purity and more significant effects in vitro. This study provides valuable insights for the advancement of MEVs isolation techniques across different species and accurate function analysis of MEVs.

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