RESUMO
The development of efficient methods for evaluating pesticide residues is essential in order to ensure the safety and quality of agricultural products since the Republic of Korea implemented the Positive List System (PLS). The objective of this research was to establish a method for the simultaneous analysis of 322 pesticide residues in fruits and vegetables (such as coffee, potato, corn, and chili pepper), using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS). This study introduces a robust, high-throughput GC-MS/MS method for screening the target pesticide residues in agricultural products, achieving the PLS criterion of 0.01 mg/kg LOQ. Despite some compounds not aligning with the CODEX recovery guideline, sufficient reproducibility was confirmed, attesting to the method's applicability in qualitative analyses. A health risk assessment conducted using estimated daily intake/acceptable daily intake ratios indicated low risks associated with product consumption (<0.035391%), thereby confirming their safety. This efficient method holds significant implications for the safe distribution of agricultural products, including during import inspections.
RESUMO
We fabricated a photodetector device consisting of ITO/NiOx/Perovskite/PC60BM/BCP/Ag. The NiOx layer was deposited using the sol-gel and combustion processes. Combustion-processed NiOx films have advantages such as low annealing temperature, improved perovskite film quality, and better photodetector performance compared to the sol-gel processed NiOx film. The improved film quality, improved charge transfer, and reduced dark current of the device using combustion-processed NiOx film were investigated by measuring the current-voltage characteristics, transient photocurrent, and impedance analysis. The photodetector using the combustion-processed NiOx achieved a high detectivity of 1.20×1013 Jones and bandwidth of over 2 MHz at -0.1 V and 550 nm.
RESUMO
We analyze and compare the differences in the dewetting phenomena and crystal structure between Ag(5.0 nm) and Au(5.0 nm) layers deposited on a Ti(1.0 nm) seed layer coated onto a MgO(001) substrate. The samples are deposited at room temperature and annealed at 350-450 °C for 5 h. The surfaces of both Ag/Ti and Au/Ti films exhibit a completely separated island structure, subsequently leading to the formation of a nanodot array after annealing. Based on atomic force microscopy (AFM) analysis, we conclude that the dewetting progression speed of Ag/Ti films is higher than that of Au/Ti films. Based on X-ray diffraction (XRD) results, the Ti thin film acts as a seed layer, assisting the epitaxial growth of fcc-Ag(001) nanodots on the MgO(001) substrate, whereas in the case of Au/Ti, the Au layer grows non-epitaxially on the MgO(001) substrate, which is related to the difference in the surface energies of Ag and Au. Furthermore, the optical absorbance spectra of the self-organized Ag and Au nanodots with the Ti seed layer are obtained in the visible light range and the optical properties of Ag and Au nanodots are compared.
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The objective of this study was to determine the presence of corticosteroids in illegal herbal medicines using ultra-high-performance liquid chromatography-tandem mass spectrometry. We collected 212 herbal medicine samples that were advertised as being effective for treatment of joint pain and bone aches. Samples were from the Korean commercial market during a span of four years (2010-2013), and the method was validated. The limits of quantification ranged from 0.47 to 15.0 ng/mL, and recoveries ranged from 80.6% to 119.5%. The intra- and interday precision ranged from 0.18% to 8.82% and from 0.09% to 8.96%, respectively. Among the samples, three samples (1.4%) were identified as adulterants. Dexamethasone was the only compound detected in the adulterated products. As the corticosteroid-adulteration of herbal medicines may become a major problem and lead to side effects, the continued development of screening procedures for herbal medicines is critical.
Assuntos
Contaminação de Medicamentos , Glucocorticoides/análise , Medicina Tradicional Coreana , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão , Dexametasona/análise , Humanos , Espectrometria de Massas , República da CoreiaRESUMO
A number of 188 food and dietary supplement samples were collected from 2009 to the first half of 2013 in Korean online and offline stores. A method to identify phosphodiesterase-5 (PDE-5) inhibitors and their analogues using liquid chromatography-electrospray ionisation-mass spectrometry/mass spectrometry (LC-ESI-MS/MS) was validated. Limit of detection and limit of quantitation of liquid-type and solid-type negative samples ranged from 0.05 to 3.33 ng/mL or ng/g and from 0.15 to 10.00 ng/mL or ng/g, respectively. Recoveries ranged from 83% to 112%. Nineteen PDE-5 inhibitors and their analogues were detected, with tadalafil group compounds being the most frequently observed (53.0%), followed by the sildenafil group (42.5%). Tadalafil concentrations ranged from 0.08 to 138.69 mg/g. Compounds were most frequently detected in capsules (in 40 of 80 adulterated samples). To protect public health and food safety, appropriate monitoring of PDE-5 inhibitors and their analogues in foods and dietary supplements is recommended.
Assuntos
Cromatografia Líquida/métodos , Suplementos Nutricionais/análise , Análise de Alimentos/métodos , Inibidores da Fosfodiesterase 5/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Contaminação de Alimentos , Humanos , Limite de Detecção , República da CoreiaRESUMO
Current colon-targeted drug-delivery approaches for colitis therapy often utilize single pH-triggered systems, which are less reliable due to the variation of gut pH in individuals and in disease conditions. Herein, we prepared budesonide-loaded dual-sensitive nanoparticles using enzyme-sensitive azo-polyurethane and pH-sensitive methacrylate copolymer for the treatment of colitis. The therapeutic potential of the enzyme/pH dual-sensitive nanoparticles was evaluated using a rat colitis model and compared to single pH-triggered nanoparticles. Clinical activity scores, colon/body weight ratios, myeloperoxidase activity, and proinflammatory cytokine levels were markedly decreased by dual-sensitive nanoparticles compared to single pH-triggered nanoparticles and budesonide solution. Moreover, dual-sensitive nanoparticles accumulated selectively in inflamed segments of the colon. In addition, dual-sensitive nanoparticle plasma concentrations were lower than single pH-triggered nanoparticles, and no noticeable in vitro or in vivo toxicity was observed. Our results demonstrate that enzyme/pH dual-sensitive nanoparticles are an effective and safe colon-targeted delivery system for colitis therapy.
Assuntos
Budesonida , Colite/tratamento farmacológico , Animais , Budesonida/química , Budesonida/farmacologia , Budesonida/uso terapêutico , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Concentração de Íons de Hidrogênio , RatosRESUMO
A tadalafil analogue was detected in an herbal product by high performance liquid chromatography-diode array detector (HPLC-DAD) with a similar chromatographic retention time to tadalafil. The compounds were separated using semi-preparative HPLC. The structure of the detected tadalafil analogue was elucidated by LC-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) and nuclear magnetic resonance (NMR) spectroscopy. A positive ion at m/z 404.1644 was detected by LC-Q-TOF/MS, corresponding to a molecular formula of C23H22N3O4. This unknown compound was identified as an analogue of tadalafil containing an additional methylene group and named homotadalafil. Homotadalafil was detected in 10 of 91 herbal products at concentrations of 0.058mgg(-1) to 8.735mgg(-1).
Assuntos
Medicina Herbária , Inibidores da Fosfodiesterase 5/análise , Tadalafila/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Espectrofotometria Ultravioleta , Tadalafila/análiseRESUMO
The purpose of this study was to develop and validate an ultra-performance liquid chromatography method for simultaneous analysis of 20 antihistamines (illegal additives) in dietary supplements. The limits of detection and quantitation of the method ranged from 1.5 to 2.5 µg/mL and from 20.0 to 50.0 µg/mL, respectively. The determination coefficient was >0.999, precisions were 0.2-5.1% (intra-day) and 0.1-8.8% (inter-day), and accuracies were 84.5-111.2% (intra-day) and 91.9-112.0% (inter-day). The mean recoveries of 20 targeted compounds from dietary supplements ranged from 75.4 to 119.3%. The relative standard deviations were <6.6% and complied with established international guidelines. The relative standard deviation of stability was <0.8%. Fifty-two commercially available dietary supplements were evaluated using this method, and were found to have none of the 20 antihistamines in significant abundance.
Assuntos
Cromatografia Líquida/métodos , Suplementos Nutricionais/análise , Antagonistas dos Receptores Histamínicos/análise , Estabilidade de Medicamentos , Sensibilidade e EspecificidadeRESUMO
8p11 myeloproliferative syndrome (EMS) is a rare disease characterized by myeloproliferative neoplasm (MPN) associated with eosinophilia and T or B lymphoblastic lymphoma/leukemia. EMS is defined by molecular disruption of the FGFR1 gene at the 8p11-12 chromosome locus, and various partner genes are associated with FGFR1 gene translocation or insertion. The different partner-FGFR1 fusion genes are associated with slightly different disease phenotypes. The present patient showed T lymphoblastic lymphoma in a cervical lymph node, involvement of malignant lymphoma in the skin, and MPN bone marrow morphology with peripheral monocytosis. Chromosome analysis of the patient showed t(1;8)(q25;p11.2). To our knowledge, only 2 cases of EMS with translocation of t(1;8)(q25;p11.2) have been previously reported. Including this case, all 3 cases with EMS with t(1;8)(q25;p11.2) showed MPN bone marrow morphology and peripheral monocytosis. These findings support that t(1;8)(q25;p11.2) is associated with peripheral monocytosis in EMS patients. Of the 2 cases of EMS with t(1;8)(q25;p11.2) which were previously reported, FGFR1 rearrangement was not confirmed in 1 case. Similarly, FGFR1 rearrangement in the present case was not detected by fluorescence in situ hybridization or reverse transcription-polymerase chain reaction. Further study is needed to identify other techniques that could be used to demonstrate FGFR1 rearrangement.
Assuntos
Cromossomos Humanos Par 1 , Cromossomos Humanos Par 8 , Transtornos Mieloproliferativos/genética , Translocação Genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Medula Óssea/patologia , Bandeamento Cromossômico , Humanos , Hibridização in Situ Fluorescente , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Transtornos Mieloproliferativos/diagnóstico , Transtornos Mieloproliferativos/tratamento farmacológico , Pele/patologia , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
The adulteration of foods and dietary supplements with steroids has been well attested and has the potential to be dangerous owing to various possible side-effects. Therefore, detecting the presence of steroids in various health food products has become increasingly important. The purpose of this study was to monitor illegally adulterated health food products by applying multiple reaction monitoring techniques to tandem liquid chromatography-mass spectrometry (LC-MS/MS). Various food and supplement samples advertised for the treatment of arthritis, bone ache and joint pain were collected over a 4-year period (2010-13) from local and online Korean sources. The method was validated based on limits of quantification of 0.5-15.0 ng g(-1) and recoveries in spiked solid samples of 81-119%. Approximately 30% of the tested samples were identified as having been illicitly adulterated. Six compounds were observed overall, including dexamethasone (45.1%), cotrisone-21-aceteate and prednisone-21-acetate (16.2%), and betamethasone (14.4%), and found in some samples in high concentrations.
Assuntos
Suplementos Nutricionais , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Esteroides/química , Cromatografia Líquida/métodos , Humanos , Reprodutibilidade dos Testes , República da Coreia , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem/métodosRESUMO
Commercially available non-opioid analgesics such as acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs) have been used to adulterate some foods and dietary supplements. Considering the rapid growth of the dietary supplement market, it is essential to analyse various analgesics used for adulteration over a time period. Acetaminophen and 16 NSAIDs used to adulterate food and dietary supplements were simultaneously determined by LC-MS/MS. The method was validated by determining the coefficient of determinations, limit of quantification and recovery, and samples were analysed for the determination of analgesics. Consequently, acetaminophen, diclofenac, ibuprofen, indomethacin, naproxen and piroxicam were detected in 53 samples (n = 214). Ibuprofen was the most commonly used adulterant, which was detected in a wide concentration range (1.06-233.40 mg g(-1)) and was present in about one-third of the adulterated samples. Various types of samples, in particular pills and capsules (73.6% of the total positive samples), were found to be adulterated with non-opioid analgesics. Samples containing high concentrations of analgesics can have a deleterious effect on human health, and thus the continued monitoring of adulterated food and dietary supplements is essential to maintain a healthy life.
Assuntos
Analgésicos não Narcóticos/análise , Suplementos Nutricionais/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Acetaminofen/análise , Acetaminofen/toxicidade , Analgésicos não Narcóticos/toxicidade , Anti-Inflamatórios não Esteroides/análise , Anti-Inflamatórios não Esteroides/toxicidade , Cromatografia Líquida , Suplementos Nutricionais/toxicidade , Humanos , República da Coreia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
Because of the rapid growth in dietary supplement availability and public concern for weight control, the investigation of foods and various dietary supplements illegally adulterated with weight loss compounds has become increasingly important. A total of 29 weight loss compounds, including sennoside, sibutramine, ephedrine and their analogues, found to be adulterated in foods and dietary supplements were simultaneously examined by LC-MS/MS. The 188 samples were collected between 2009 and 2012 in South Korea, and method validation was performed to determine the adulterants to the weight loss compounds. LODs, LOQs and linearity ranged from 0.03 to 7.5 ng ml⻹, from 0.08 to 30.00 ng ml⻹, and from 0.990 to 0.999, respectively. The results showed that nine weight loss compounds, namely bisacodyl, desmethylsibutramine, didesmethylsibutramine, ephedrine, fluoxetine, pseudoephedrine, sennoside A, sennoside B and sibutramine, were detected in 62 of all collected samples and were found in order of frequency as follows: sibutramine, 25.7%; sennoside A, 22.9%; sennoside B, 20.0%; fluoxetine, 8.6%; desmethylsibutramine, 7.1%; bisacodyl, ephedrine, and pseudoephedrine, 4.3%; and didesmethylsibutramine, 2.9%. Sibutramine, which was the most frequently found adulterant, ranged in levels from 0.03 to 132.40 mg g⻹ (2010), from 0.88 to 76.2 mg g⻹ (2011), and from 0.07 to 0.24 mg g⻹ (2012). Although the concentrations of most compounds ranged widely, some compounds such as bisacodyl and fluoxetine were found at high concentrations in several samples.
Assuntos
Fármacos Antiobesidade/análise , Suplementos Nutricionais/análise , Contaminação de Alimentos , Inspeção de Alimentos/métodos , Alimentos em Conserva/análise , Fármacos Antiobesidade/química , Depressores do Apetite/análise , Depressores do Apetite/química , Catárticos/análise , Catárticos/química , Estimulantes do Sistema Nervoso Central/análise , Estimulantes do Sistema Nervoso Central/química , Cromatografia Líquida de Alta Pressão , Ciclobutanos/análise , Ciclobutanos/química , Suplementos Nutricionais/economia , Alimentos em Conserva/economia , Limite de Detecção , Reprodutibilidade dos Testes , República da Coreia , Extrato de Senna/análise , Extrato de Senna/química , Senosídeos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
A novel phosphodiesterase-5 (PDE-5) inhibitor was found in a natural health food product. The previously unknown sildenafil analogue was isolated using preparative HPLC. The structure of the compound was elucidated using HPLC with diode array detection (DAD), time-of-flight mass spectrometry (TOF/MS), and nuclear magnetic resonance spectroscopy (NMR). An [M + H](+) ion was detected at m/z 505.2077 by LC-TOF/MS that was consistent with C23H32N6O3S2 (-0.98 ppm). By NMR analysis, the analogue was identified as 1-methyl-5-(5-(4-methylpiperazin-1-ylsulfonyl)-2-propoxyphenyl)-3-propyl-1H-pyrazolo[4,3-d]pyrimidine-7(6H)-thione. In this structure, the ethoxy group of thiosildenafil was substituted by a propoxy group of the unknown compound. Therefore, this novel thiosildenafil analogue was named propoxyphenyl thiosildenafil.
Assuntos
Contaminação de Alimentos/análise , Alimentos Orgânicos/análise , Inibidores da Fosfodiesterase 5/isolamento & purificação , Pirimidinas/isolamento & purificação , Sulfonas/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Alimentos Orgânicos/efeitos adversos , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Estrutura Molecular , Inibidores da Fosfodiesterase 5/efeitos adversos , Inibidores da Fosfodiesterase 5/química , Pirimidinas/efeitos adversos , Pirimidinas/química , República da Coreia , Espectrometria de Massas por Ionização por Electrospray , Sulfonas/efeitos adversos , Sulfonas/químicaRESUMO
Extraordinary performance at elevated temperature is achieved for high-voltage spinel-phase LiNi0.5 Mn1.5 O4 cathodes prepared using an adipic-acid-assisted sol-gel technique and doped with vanadium. V-substitution in the Li sites (Wykoff position 8a) is confirmed by V K-edge X-ray absorption spectroscopy and Rietveld refinement (Li0.995 V0.005 Ni0.5 Mn1.5 O4 ). V-doped LiNi0.5 Mn1.5 O4 delivered a reversible capacity of approximately 130 and 142â mAh g(-1) at ambient and elevated temperature conditions, respectively. Furthermore, the Li0.995 V0.005 Ni0.5 Mn1.5 O4 phase rendered approximately 94 % and 84 % of initial capacity compared to approximately 85 % and 3 % for the LiNi0.5 Mn1.5 O4 phase after 100 cycles in ambient and elevated temperature conditions, respectively. The enhancements are mainly because of the suppression of Mn dissolution and unwanted side reaction with electrolyte counterpart, and to the increase in conductivity, improving the electrochemical profiles for the V-doped phase.
Assuntos
Técnicas de Química Sintética , Fontes de Energia Elétrica , Lítio/química , Manganês/química , Níquel/química , Temperatura , Vanádio/química , Eletroquímica , Eletrodos , GéisRESUMO
More than 46 phosphodiesterase type 5 (PDE5) inhibitor analogues have been found to be present as illegal adulterants in various forms of health food products (powder, tablet, capsule, etc.), thereby placing the health of consumers at risk through product intake. In this study, 164 samples advertised to be effective at enhancing male sexual performance were collected over a 4-year period (2009-2012) from the Korean on-line or off-line market and screened. An LC-MS/MS method was employed to screen for the presence of 48 compounds including sildenafil, tadalafil, vardenafil and their analogues. Method validation established LOQs (0.30-10.00 ng ml(-1) or ng g(-1)) and recoveries (spiked in liquid sample, 84-112%; spiked in solid sample, 83-110%). Most of the illicit products screened were adulterated with 14 of the PDE5 derivatives under examination, including considerable amounts of sildenafil and tadalafil; of the 48 compounds, tadalafil was the most frequent adulterant (42.6%), followed by sildenafil (27.9%). Specifically, tadalafil concentration ranges (mg g(-1)) in the samples collected over the 4-year period were determined as follows: 2.91-52.20 (2009), 4.50-108.10 (2010), 0.37-101.40 (2011), and 0.08-138.69 mg g(-1) (2012). The concentration ranges (mg g(-1)) of sildenafil were also at high levels: 4.90-117.96 (2009), 1.30-369.93 (2010), 0.03-241.77 (2011), and 18.34-297.91 mg g(-1) (2012). The results of screening for PDE5 inhibitor pharmaceuticals as adulterants in illicit health food products are of great significance with respect to the protection of public health and consumer safety.
Assuntos
Carbolinas/análise , Contaminação de Alimentos/análise , Alimentos Orgânicos/análise , Imidazóis/análise , Inibidores da Fosfodiesterase 5/análise , Piperazinas/análise , Sulfonas/análise , Publicidade , Cromatografia Líquida , Humanos , Masculino , Purinas/análise , Saúde Reprodutiva , República da Coreia , Citrato de Sildenafila , Detecção do Abuso de Substâncias/métodos , Tadalafila , Espectrometria de Massas em Tandem , Triazinas/análise , Dicloridrato de VardenafilaRESUMO
A propoxyphenyl-linked thiohomosildenafil analogue, one of the sildenafil analogues, was found in an herbal product. It was isolated by semi-preparative high-performance liquid chromatography (HPLC). The structure was established based on a comparison of chromatographic and spectroscopic behaviour with other sildenafil analogues using HPLC with diode array detection, quadrupole time-of-flight mass spectrometry (Q-TOF/MS), and nuclear magnetic resonance (NMR) spectroscopy. The HPLC analysis showed separation from known sildenafil analogues with a similar chromatographic retention time. An [M + H](+) ion at m/z 519.22 was detected by mass spectrometry corresponding to an empirical formula of C24H34N6O3S2. The structure was similar to that of thiohomosildenafil, except that the ethoxy group attached to the phenyl ring was substituted for a propoxy group. It was assigned as 5-[2-propoxy-5-(4-ethylpiperazin-4-ylsulfonyl)phenyl]-3-methyl-1-n-propyl-4,5,dihydro-1H-pyrazole[7,1,d]pyrimidin-4-thione and named as propoxyphenyl-thiohomosildenafil because the structure was considerably similar to thiohomosildenafil.
Assuntos
Contaminação de Alimentos/análise , Inibidores da Fosfodiesterase 5/química , Piperazinas/química , Preparações de Plantas/química , Sulfonas/química , Cromatografia Líquida de Alta Pressão , Suplementos Nutricionais/efeitos adversos , Suplementos Nutricionais/análise , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Purinas/química , Citrato de SildenafilaRESUMO
Porous LiFePO4/C microspheres were synthesized by a novel hydrothermal reaction combined with high-temperature calcinations. The morphology of the prepared material was investigated by field-emission scanning electron microscopy. Porous microspheres with diameters around 1-3 microm were obtained, which consisting of primary LiFePO4 nanoparticles. The electrochemical performances of the as-prepared LiFePO4 microspheres were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling. The carbon coated LiFePO4 microspheres showed lower polarization, higher rate capability, and better cycling stability than that of pristine LiFePO4 microspheres, indicating the potential application as the cathode material for high-power lithium ion batteries.
Assuntos
Carbono/química , Fontes de Energia Elétrica , Eletrodos , Compostos Férricos/química , Lítio/química , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Íons , MicroesferasRESUMO
A suspected sibutramine analogue was detected in a slimming functional food by an ultra performance liquid chromatography-electrospray ionisation-time of flight mass spectrometry (UPLC-ESI-TOF/MS) method. The ultraviolet (UV) spectrum of this suspected compound showed close similarity to that of sibutramine. The sample was extracted with 70% MeOH and isolated by semi-preparative column chromatography. The structure of this compound was identified by spectroscopic analyses (nuclear magnetic resonance [NMR] technique, mass and tandem mass etc.). The structure of the unknown compound was demonstrated to be [(±)-dimethyl-1-[1-(3,4-dichlorophenyl)cyclobutyl]-N,N,3-trimethylbutan-1-amine (molecular formula C17H25NCl2) and named as chloro-sibutramine. Compared with sibutramine, it has one more chlorine atom than the 3-cholorophenyl group so was switched to 3,4-dichlorophenyl. Until now, chloro-sibutramine was isolated for the first time from the undeclared ingredient included in dietary supplements. Although the safety of chloro-sibutramine is unknown, there is a potential health risk to consumers because of a similar skeleton to sibutramine. For public health, this sibutramine analogue has been included in the inspection list of illegal adulterants in Korea.
Assuntos
Depressores do Apetite/análise , Ciclobutanos/análise , Suplementos Nutricionais , Contaminação de Medicamentos , Cromatografia Líquida , Ciclobutanos/química , Espectroscopia de Ressonância MagnéticaRESUMO
Mesoporous nickel oxide nanowires were synthesized by a hydrothermal reaction and subsequent annealing at 400 °C. The porous one-dimensional nanostructures were analysed by field-emission SEM, high-resolution TEM and N(2) adsorption/desorption isotherm measurements. When applied as the anode material in lithium-ion batteries, the as-prepared mesoporous nickel oxide nanowires demonstrated outstanding electrochemical performance with high lithium storage capacity, satisfactory cyclability and an excellent rate capacity. They also exhibited a high specific capacitance of 348â F g(-1) as electrodes in supercapacitors.
RESUMO
γ-Butyrolactones in Streptomyces are well recognized as bacterial hormones, and they affect secondary metabolism of Streptomyces. γ-Butyrolactone receptors are considered important regulatory proteins, and various γ-butyrolactone synthases and receptors have been reported in Streptomyces. Here, we characterized a new regulator, SCO0608, that interacted with SCB1 (γ-butyrolactone of Streptomyces coelicolor) and bound to the scbR/A and adpA promoters. The SCO0608 protein sequences are not similar to those of any known γ-butyrolactone binding proteins in Streptomyces such as ScbR from S. coelicolor or ArpA from Streptomyces griseus. Interestingly, SCO0608 functions as a repressor of antibiotic biosynthesis and spore formation in R5 complex media. We showed the existence of another type of γ-butyrolactone receptor in Streptomyces, and this SCO0608 was named ScbR-like γ-butyrolactone binding regulator (SlbR) in S. coelicolor.