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Objective: To evaluate the clinical characteristics of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) combined with alveolar hypoventilation. Methods: This retrospective study included patients who were diagnosed as OSAHS by polysomnography (PSG) and underwent daytime awake transcutaneous carbon dioxide (PtcCO2) monitoring from November 2019 to February 2021 at the Sleep Center of the Second Affiliated Hospital of Soochow University. A total of 177 patients were enrolled in the analysis, including 167 males and 10 females, aged (40±8) years old. Patients with daytime awake PtcCO2>45 mmHg (1 mmHg=0.133 kPa) were diagnosed as daytime alveolar hypoventilation, with which participants were divided into the daytime alveolar hypoventilation group and non-daytime alveolar hypoventilation group. Body mass index (BMI) cut-off value predicting daytime alveolar hypoventilation was calculated and the patients were divided into the high BMI group and low BMI group. The continuous nocturnal PtcCO2 data was available for a subset of 128 patients, and the patients were divided into two groups according the daytime alveolar hypoventilation or not. Across-group differences were compared, respectively. Results: Compared with the non-daytime alveolar hypoventilation group (n=125), the BMI [27.57 (26.55, 30.33) vs 26.60 (25.06, 28.09) kg/m2], Epworth sleepiness score(ESS) score [9.50 (6.25, 12.00) vs 7.00 (4.00, 10.75)], higher oxygen desaturation index (ODI) [38.00 (15.23, 64.93) vs 26.80 (11.30, 44.30) events/h] and percentage of total time with oxygen saturation level<90% (TS90%) [11.24% (1.88%, 32.44%) vs 4.35% (0.72%, 9.87%)] of the daytime alveolar hypoventilation group(n=52) were significantly higher (P<0.05), and lowest arterial oxygen saturation (LSaO2) [74.50% (60.25%, 82.00%) vs 79.00% (73.00%, 84.50%)], mean arterial oxygen saturation (MSaO2) [94.00% (91.00%, 95.00%) vs 95.00% (94.00%, 96.00%)] were significantly lower (P<0.05). The BMI cut-off value for predicting daytime alveolar hypoventilation was 27.04 kg/m2. Of the 177 enrolled patients, 90 were in the high BMI group and 87 were in low group. Compared with the low BMI group, the proportion of daytime sleepiness, the ESS score, the prevalence of hypertension, AHI and daytime awake PtcCO2 in the high BMI group were significantly higher (P<0.05). Among the subset of 128 patients with nocturnal PtcCO2 data available, the BMI, daytime PtcCO2 level, the nocturnal CO2 level and the prevalence of sleep related alveolar hypoventilation in the daytime alveolar hypoventilation group (n=40) were significantly higher than those in the non-daytime alveolar hypoventilation group (n=88) (P<0.05). Conclusions: The OSAHS patients with alveolar hypoventilation have higher BMI and more severe nocturnal hypoxia. OSAHS patients with BMI>27.04 kg/m2 are more likely to develop sleep related alveolar hypoventilation disorder.
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Hipertensión , Apnea Obstructiva del Sueño , Adulto , Femenino , Humanos , Hipoventilación , Masculino , Persona de Mediana Edad , Polisomnografía , Estudios RetrospectivosRESUMEN
Objective: To study the characteristics of cardiopulmonary function in patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) overlapping syndrome (OS). Methods: A total of 149 COPD patients, who were on stable treatment, were enrolled from the Second Affiliated Hospital of Soochow University from December 2017 to December 2019. The patients were divided into the OS group (n=56) and the COPD only group (n=93) according to their apnea hypopnea index (AHI) measured by the Apnealink device. Data were gathered from polysomnograph (PSG), spirometry, arterial blood gas and N-terminal pro-brain natriuretic peptide (NT-proBNP) assay to assess the cardiopulmonary function of patients. Partial correlation analysis was used to analyze the correlation between AHI and various factors, to study the characteristic changes in the cardiopulmonary function of these OS patients. Results: There were no significant cross-group differences in age and gender (all P>0.05). In the OS group, the forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC), the forced expiratory volume in the first second expressed as percent predicted (FEV1%pred), pH[M (Q1, Q3)], partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) were lower than those in the COPD group [(49.46±12.98)% vs (54.38±11.72)%, (47.86±14.78)% vs (57.78±15.81)%, 7.37(7.34, 7.39) vs 7.40(7.39, 7.41), (80.75±10.20) vs (84.28±8.43) mmHg (1 mmHg=0.133 kPa), (94.46±2.52)% vs (95.74±2.28)%], whereas partial pressure of carbon dioxide (PaCO2) [M (Q1, Q3)] was higher than that in the COPD group [55.00 (45.50, 60.00) vs 44.00(40.00, 48.00)mmHg] (all P<0.05). Pulmonary arterial pressure and plasma NT-proBNP levels [M (Q1, Q3)] in the OS group were significantly higher than those in the COPD group [38.90 (28.60, 49.05) vs 28.60 (24.95, 32.60) mmHg, 434.00 (273.75, 631.00) vs 136.00 (86.00, 205.00) pg/ml] (P<0.05). Partial correlation analysis showed that AHI was positively correlated with PaCO2, pulmonary artery pressure, NT-proBNP, and acute exacerbation events (r values: 0.496, 0.544, 0.628, 0.446), and negatively correlated with FEV1/FVC, FEV1%pred, pH, PaO2, and SaO2 (r values:-0.309, -0.346, -0.410, -0.289, -0.267) (all P<0.05). Conclusion: Patients with OS suffer from more severe hypoxemia, hypercapnia and pulmonary function damage, and their pulmonary arterial pressure and NT-proBNP are significantly higher than those with COPD only.
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Enfermedad Pulmonar Obstructiva Crónica , Apnea Obstructiva del Sueño , Volumen Espiratorio Forzado , Humanos , Polisomnografía , Pruebas de Función RespiratoriaRESUMEN
Objective: To explore the relationship of sleep quality and sleep duration with hypertension among adults aged 30-79 years old in Guangzhou. Methods: According to multi-stage stratified cluster sampling, 12 747 residents aged 30-79 years old were sampled and surveyed in Guangzhou from January 2018 to March 2019. Data on general demographic characteristics, sleep quality, sleep duration and hypertension were collected through questionnaire survey, the Pittsburgh sleep quality index (PSQI) and physical examination. Multivariate logistic regression models were used to analyze the putative association between sleep quality, sleep duration and hypertension. Restrictive cubic spline curve was used to draw the dose-response relationship curve between sleep quality, sleep time and hypertension. Results: The mean age of the subjects was (52.68±12.17) years, the prevalence of hypertension was 36.6% (4 664/12 747), the average score of PSQI was (4.70±2.88), and the average sleep time was (7.00±1.32) hours. The prevalence of hypertension was positively associated with the PSQI score. Compared to the subjects with a score less than 3, OR (95%CI) of hypertension with a PSQI score of 3-5, 5-8, ≥9 were 1.14 (1.02-1.27), 1.17 (1.03-1.34), 1.41 (1.21-1.64), respectively. The relationship between sleep duration and hypertension appeared U-shaped. Compared with 6 to 8 hours sleep duration, both sleep duration<6 hours with OR(95%CI) of 1.27(1.12-1.43) or >8 hours with OR(95%CI) of 1.20(1.05-1.38) was associated with hypertension. Conclusion: Both poor sleep quality, longer or shorter sleep duration were responsible for increased risk of cognitive impairment in older Chinese.
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Hipertensión , Trastornos del Inicio y del Mantenimiento del Sueño , Trastornos del Sueño-Vigilia , Adulto , Anciano , China/epidemiología , Estudios Transversales , Humanos , Hipertensión/epidemiología , Persona de Mediana Edad , Prevalencia , Sueño , Trastornos del Sueño-Vigilia/epidemiología , Factores de TiempoRESUMEN
Objective: To explore the relationship between insomnia phenotype and mild cognitive impairment (MCI) in young and middle-aged patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods: Those patients admitted due to snoring and examined by polysomnography (PSG) in the Sleep Center of the Second Affiliated Hospital of Soochow University from January 2014 to January 2019 were screened. They were between 30 and 60 years old, and their cognitive function was assessed by the Montreal cognitive assessment (MoCA) and their sleep quality was assessed by the Pittsburgh sleep quality index (PSQI). According to the sleep apnea hypopnea index (AHI), the patients were divided into three groups: snoring group (AHI<5 times/h), mild/moderate OSAHS group (5≤AHI≤30 times/h) and severe OSAHS group (AHI>30 times/h). According to the results of PSQI score, the patients were further divided into non-insomnia group (PSQI total score<8) and insomnia group (PSQI total score≥8). The differences of parameters in different groups were compared, and the relationship between OSAHS insomnia phenotype and MCI was analyzed by binary logistic regression model. Results: A total of 2 098 patients with the average age of (42.7±8.4) years old and the average BMI of (26.3±3.6) kg/m(2) were enrolled in the study, including 398 cases in snoring group (including 254 cases in non-insomnia group and 144 cases in insomnia group), 754 cases in mild/moderate OSAHS group (including 446 cases in non-insomnia group and 308 cases in insomnia group) and 946 cases in severe OSAHS group (including 722 cases in non-insomnia group and 224 cases in insomnia group). In the mild/moderate OSAHS group, compared with the non-insomnia group, the proportion of women in the insomnia group was higher with lighter degree of obesity, lighter severity of illness and lighter degree of hypoxia (all P<0.05). In the severe OSAHS group, the general characteristics of insomnia patients were similar to those of the mild/moderate OSAHS group, and the MoCA score of the insomnia group was lower than that of the non-insomnia group [(26.3±2.7) vs (25.5±2.9) points] (P=0.001). In the evaluation of each item of PSQI, the total score and daytime dysfunction score of insomnia patients in mild/moderate OSAHS group and severe OSAHS group was higher than those in snoring group [(11.2±1.9) points, (12.8±2.2) points vs (10.9±2.1) points and (1.5±0.4) points, (1.9±0.8) points vs (0.5±0.5) points], but the score in sleep latency was lower than that in snoring group [(1.5±0.5) points, (1.5±0.5) points vs (2.1±0.8) points] (all P<0.05). After correcting the effects of OSAHS disease severity, hypoxia, awake times, education, age, gender, hypnagogue, BMI, smoking and drinking history, the risk of MCI in insomnia group of severe OSAHS patients was significantly higher than that of non-insomnia group by 49% (OR=1.49, 95%CI: 1.05-2.11). Conclusion: Insomnia phenotype is a common clinical phenotype of OSAHS, and it is a risk factor for MCI in young and middle-aged patients with severe OSAHS.
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Disfunción Cognitiva , Apnea Obstructiva del Sueño , Trastornos del Inicio y del Mantenimiento del Sueño , Adulto , Femenino , Humanos , Persona de Mediana Edad , Fenotipo , PolisomnografíaRESUMEN
Soil erosion in karst areas not only destroys the natural environment but also accelerates the decline in land productivity together with the associated increase in poverty for local communities. There are no simple or straightforward answers to controlling soil erosion on karst. Such erosion has become a serious problem in China. This study addresses both the diversity of vegetation (mosses, herbs, shrubs and trees) on karst and the underlying soil chemical characteristics, in order to provide a scientific basis by which suitable plant species can be selected for recovery and restoration of karst degraded by soil erosion. Vegetation diversity and soil chemistry were assessed in areas with five different grades of soil erosion in Guiyang Karst Park, Guizhou, China. Mosses are more tolerant than vascular plants of soil erosion and associated environmental degradation of karst and the order of species diversity was: mosses > herbs > shrubs > trees. Mosses were found to play a major role in ecological restoration of microhabitats on karst. Soil microbial biomass carbon was found to be significantly higher in soil under mosses than in bare soil associated with other plant categories. Mosses were more effective in converting unavailable potassium to available potassium. Vascular plants were found to have a positive effect on total nitrogen fixation and the availability of phosphorus in the soil. Increasing soil degradation was associated with lower levels of total Nitrogen in soil underlying mosses than in soil underlying vascular plants. Thus, based on their different but complementary contributions to soil chemistry, mosses and vascular plants in combination can provide the most practical outcome for the repair and restoration of areas of karst affected by soil erosion. The combination of the moss species, Homomallium plagiangium, Cyrto-hypnum pygmaeuman and Brachythecium perminusculum, the herbs Veronica arvensis and Youngia japonica, and the tree Prunus salicina, are recommended as suitable pioneer plant species to cultivate for use in restoration of regions of karstic soil erosion.
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Briófitas , Suelo , Biodegradación Ambiental , China , Ecología , EcosistemaRESUMEN
The survival behaviour of Vibrio cholerae in cholera epidemics, together with its attributes of virulence-associated genes and molecular fingerprints, are significant for managing cholera epidemics. Here, we selected five strains representative of V. cholerae O1 and O139 involved in cholera events, examined their survival capacity in large volumes of water sampled from epidemic sites of a 2005 cholera outbreak, and determined virulence-associated genes and molecular subtype changes of the surviving isolates recovered. The five strains exhibited different survival capacities varying from 17 to 38 days. The virulence-associated genes of the surviving isolates remained unchanged, while their pulsotypes underwent slight variation. In particular, one waterway-isolated strain maintained virulence-associated genes and evolved to share the same pulsotype as patient strains, highlighting its role in the cholera outbreak. The strong survival capacity and molecular attributes of V. cholerae might account for its persistence in environmental waters and the long duration of the cholera outbreak, allowing effective control measures.
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Cólera/microbiología , Epidemias/estadística & datos numéricos , Vibrio cholerae/genética , Vibrio cholerae/aislamiento & purificación , Microbiología del Agua , China/epidemiología , Cólera/epidemiología , Electroforesis en Gel de Campo Pulsado , Humanos , Océanos y Mares , Vibrio cholerae/clasificación , Vibrio cholerae/fisiologíaRESUMEN
Hemangioma is a tumor that causes vascular endothelial cell hyperplasia, which commonly occur in newborns. Angiogenesis inhibitor targets the processes of angiogenesis, including the proliferation of vascular endothelial cells. A DNA sequence named Scl was designed, recombined into Pichia Pastoris, expressed by fermenting the engineered strain in a bioreactor, and purified the recombinant Scl by SP-sepharose fast flow. Scl can inhibit CAM angiogenesis. Only 1 µg of Scl significantly suppressed the growth of CAM blood vessel, similar to that of 25 µg of angiostatin. Scl showed a strong cytotoxicity on hemangioma cell (ATCC CRL No. 2587). After the drug acted for 24 h, the OD 570 measured value of the PBS control group averaged 1.873, whereas that of the Sc1 drug group was 0.692 (P < 0.01). Using the DeadEndTM Fluorometric TUNEL System, the detection results showed that 92 % of hemangioma cell apoptosis was observed in the Scl protein group, but only 1.3 % in the PBS control group (P < 0.01). After 2 weeks of treatment with the hemangioma model (cock's wattle) of the PBS group, 151 blood vessels with 100 views (40×) were obtained, whereas 250 in the PBS group (P < 0.01). During the two-week medication, the hemangioma model of the PBS group increased by 1.18 cm, whereas only 0.58 cm in the Scl drug group (P < 0.01).
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Células Endoteliales/efectos de los fármacos , Hemangioma/tratamiento farmacológico , Hiperplasia/genética , Neovascularización Patológica/tratamiento farmacológico , Péptidos/administración & dosificación , Inhibidores de la Angiogénesis/administración & dosificación , Animales , Apoptosis/efectos de los fármacos , Secuencia de Bases , Línea Celular Tumoral , Pollos/genética , Pollos/crecimiento & desarrollo , Células Endoteliales/patología , Hemangioma/genética , Hemangioma/patología , Humanos , Hiperplasia/tratamiento farmacológico , Hiperplasia/patología , Datos de Secuencia Molecular , Neovascularización Patológica/genética , Péptidos/síntesis química , Péptidos/genética , PichiaRESUMEN
Werner syndrome (WS) is an uncommon autosomal recessive disorder characterized by premature aging. The clinical manifestations of WS, including atherosclerosis and osteoporosis, appear early in adulthood, and death in the fourth to sixth decade commonly ensues from myocardial infarction or cancer. In accord with the aging phenotype, cells from WS patients have a reduced replicative life span in culture. Genomic instability is observed at the cytogenetic level in the form of chromosome breaks and translocations and at the molecular level by multiple large deletions. The Werner syndrome gene (WRN) has recently been cloned. The predicted product is a 1,432-amino-acid protein whose central domain is homologous to members of the RecQ family of DNA helicases. Such homology does not necessarily mean that WRN encodes an active helicase. For example, the Saccharomyces cerevisiae RAD26 gene protein and the human transcription-repair coupling factor CSB (Cockayne syndrome 8) are highly homologous to known helicases, yet neither encodes an active helicase. Moreover, the Bloom's syndrome gene (BLM), discovered before WRN, is also homologous to the RecQ family of DNA helicases, though we still await demonstration that it encodes an active helicase. Here we report that the WS protein does indeed catalyze DNA unwinding.
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ADN Helicasas/genética , Mutación Puntual , Síndrome de Werner/enzimología , Síndrome de Werner/genética , Adulto , Secuencia de Aminoácidos , Animales , Línea Celular , Secuencia Conservada , ADN Helicasas/aislamiento & purificación , ADN Helicasas/metabolismo , Humanos , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Spodoptera , TransfecciónRESUMEN
α-amy gene amplified from barley genome was cloned into MCS of pGAP9K to generate pGAP9K-α-amy which was then transformed into Pichia pastoris GS115 by electroporation. Transformants with multi-copies and high expression for the foreign gene were selected on G418 containing plate and expression analysis. The fermentation was carried out in a 50 l bioreactor with 20 l working volume, using a high-density cell culture method by continuously feeding with 50% glycerol-0.8% PTM4 to the growing culture for 54 h at 30°C. Under the control of GAP promoter (pGAP), α-amy gene was constitutively expressed. At the end of the fermentation, the α-AMY expression reached 125 mg/l, while the biomass growth was 186 as measured by absorption of 600 nm. The secreted α-AMY was purified to 97.5% by SP-Sepharose FF ion-exchange chromatography and affinity purification. The recombinant α-AMY showed activity on hydrolysis of starch.
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Técnicas de Cultivo de Célula/métodos , Hordeum/enzimología , Pichia/crecimiento & desarrollo , Pichia/metabolismo , alfa-Amilasas/metabolismo , Biomasa , Electroforesis en Gel de Poliacrilamida , Fermentación/efectos de los fármacos , Dosificación de Gen/genética , Hordeum/citología , Hordeum/efectos de los fármacos , Hidrólisis/efectos de los fármacos , Peptonas/farmacología , Pichia/citología , Pichia/efectos de los fármacos , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/aislamiento & purificación , Almidón/metabolismo , Transformación Genética/efectos de los fármacos , alfa-Amilasas/aislamiento & purificaciónRESUMEN
The photoluminescence (PL) characteristics of Mn(2+)-bonded reduced graphene oxide (rGO) are studied in details. The Mn(2+)-bonded rGO is synthesized using MnO(2)-decorated GO as the intermediate products and ideal tunable PL is obtained by enhancing the long-wavelength (450-550 nm) emission. The PL spectra excited by different wavelengths are analyzed to elucidate the mechanism, and the resonant energy transfer between Mn(2+) and sp(2) clusters of the rGO appears to be responsible for the enhanced long-wavelength emission. To examine the effect of Mn(2+) on the long-wavelength emission from the Mn(2+)-bonded rGO, the PL characteristics of Mn(2+)-bonded rGO with smaller Mn concentrations are studied and weaker emission is observed. Our theoretical calculation corroborates the experimental results.
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Grafito/química , Manganeso/química , Óxidos/química , Transferencia de Energía , Diseño de Equipo , Luminiscencia , Microscopía Electrónica de Transmisión/métodos , Modelos Químicos , Nanoestructuras/química , Fotoquímica/métodos , Teoría Cuántica , Espectroscopía Infrarroja por Transformada de Fourier/métodos , TemperaturaRESUMEN
In this paper, we report the synthesis of crystalline beta-FeSi2 via the reaction of Si and Fe powders under high-temperature and high-pressure. X-ray diffraction and Raman scattering results confirm formation of the beta-FeSi2 phase. Scanning electron microscopy, high-resolution transmission electron microscopy, and selected-area electron diffraction patterns show that the beta-FeSi2 phase coexists with Si phase with small nanocrystal sizes. The formation of the beta-FeSi2 phase is a result of Si diffusion into Fe region. The obtained results suggest that the removal of Si phase can be reached through increasing Fe content and prolonging the duration of high-pressure thermal treatment.
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Laser therapy has been widely used in the treatment of hypertrophic scars (HPS), but whether the mechanical properties of HPS tissue after laser treatment can be restored to those of normal skin remains unclear. In this paper, the relationship between the evolution of compressive mechanical properties and histological changes of HPS tissues following three successive combined pulsed dye laser (PDL) and fractional CO2 laser (CO2) treatments was investigated by compression tests and histological analysis. The early HPS model of rabbit ear was established by CO2 laser ablation. The loading-unloading tests and strain creep tests under the compression forces of 1 N, 2 N, and 3 N were carried out for normal skin, untreated HPS and HPS after different treatment times, respectively. The results showed that the compression ratio λ of all tissues revealed force dependence and rose with the increasing compression force, which was similar to the trend of most biological soft tissues. The histological changes of HPSs following laser treatment have a significant influence on the compressive mechanical response. Compared with the normal skin, the toughness and anti-deformation ability of HPS reduced due to the proliferation of collagen fibers and the destruction of elastic fibers, resulting in higher energy dissipation, compression ratio λ, and stable creep rate D, and lower elastic modulus. After three successive combined PDL/ CO2 laser treatments, the compressive mechanical properties and creep properties of HPS gradually approached that of the normal skin owing to the gradual restoration of the amount and distribution of collagen and elastic fibers in HPS. The results provide a new method for evaluating the clinical efficacy of laser therapy for treatment of HPS tissue.
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Cicatriz Hipertrófica , Láseres de Colorantes , Láseres de Gas , Terapia por Luz de Baja Intensidad , Animales , Cicatriz Hipertrófica/patología , Cicatriz Hipertrófica/terapia , Conejos , Resultado del TratamientoRESUMEN
SiC nanocrystals (NCs) exhibit unique surface chemistry and possess special properties. This provides the opportunity to design suitable surface structures by terminating the surface dangling bonds with different atoms thereby boding well for practical applications. In this article, we report the photoluminescence properties of 3C-SiC NCs in water suspensions with different pH values. Besides a blue band stemming from the quantum confinement effect, the 3C-SiC NCs show an additional photoluminescence band at 510 nm when the excitation wavelengths are longer than 350 nm. Its intensity relative to the blue band increases with the excitation wavelength. The 510 nm band appears only in acidic suspensions but not in alkaline ones. Fourier transform infrared, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure analyses clearly reveal that the 3C-SiC NCs in the water suspension have Si-H and Si-OH bonds on their surface, implying that water molecules only react with a Si-terminated surface. First-principle calculations suggest that the additional 510 nm band arises from structures induced by H(+) and OH(-) dissociated from water and attached to Si dimers on the modified (001) Si-terminated portion of the NCs. The size requirement is consistent with the observation that the 510 nm band can only be observed when the excitation wavelengths are relatively large, that is, excitation of bigger NCs.
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Compuestos Inorgánicos de Carbono/química , Hidrógeno/química , Mediciones Luminiscentes/métodos , Modelos Químicos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Compuestos de Silicona/química , Sitios de Unión , Simulación por Computador , Cristalización/métodos , Enlace de Hidrógeno , Hidróxidos , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Vacancy structures in tin oxide nanoribbons fabricated via thermal evaporation and post-processing are probed by luminescence spectroscopy, and interesting properties that bode well for oxygen sensing are observed. Besides a broad 620-nm band, the fabricated tin oxide nanoribbons show a photoluminescence band at 480 nm when the measurement temperature is <100 K. The blue band appears from nanoribbons synthesized under high oxygen pressure or annealed under oxygen. The dependence suggests that the oxygen interstitial and vacancy densities determine the electronic states that produce the blue band. Calculation of the electron structures based on the density functional theory shows that decreased oxygen vacancies or increased oxygen interstitials enhance the 480-nm band but suppress the 620-nm band. The results reported here indicate that the tin oxide nanoribbons with vacancy structures have potential applications in luminescence-sensitive oxygen sensing.
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Luminiscencia , Nanopartículas/química , Oxígeno/análisis , Compuestos de Estaño/química , Microscopía Electrónica de Rastreo , Nanopartículas/ultraestructuraRESUMEN
Amorphous twisted SiO(2) nanobelts have been synthesized on Si wafers using facile thermal evaporation. These nanobelts are produced together with SiO(2) nanowires and a small quantity of SiO(2) nanosprings. Spectral and microstructural analyses suggest that the twisted SiO(2) nanobelts and nanosprings form via a polar surface driven process. Spontaneous polarization on the very thin polar crystalline SiO(2) layers on the amorphous SiO(2) nanobelt and nanospring surfaces makes the nuclei rearrange orderly and causes the nanobelt and nanowire to roll up at a certain twisty angle. The cathodoluminescence spectrum acquired from these SiO(2) nanostructures reveals three emission bands at 4.4, 3.7, and 2.7 eV originating from oxygen-related defect centers. The polar surface driven mechanism can adequately explain the growth of these novel twisty nanobelts and nanosprings which have potential applications in sensors, transducers, resonators, and photonics.
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Werner syndrome (WS) is an autosomal recessive genetic disorder that is manifested by genetic instability and premature onset of age-related diseases, including atherosclerosis and cancer. The gene that is mutated in WS cells (WRN) has been identified recently. Characterizations of the WRN gene product indicate that WRN encodes both a 3'-->5' DNA helicase, belonging to the Escherichiacoli RecQ helicase family, and a 3'-->5' DNA exonuclease. Studies to define the molecular mechanism of WRN-DNA transactions are currently underway in many laboratories. Preliminary results indicate that WRN functions as a key factor in resolving aberrant DNA structures that arise from DNA metabolic processes such as replication, recombination and/or repair, to preserve the genetic integrity in cells.
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ADN Helicasas/genética , ADN Helicasas/metabolismo , Síndrome de Werner/genética , Adenosina Trifosfatasas/genética , Animales , Reparación del ADN , Replicación del ADN , Proteínas de Unión al ADN/metabolismo , Modelos Animales de Enfermedad , Exodesoxirribonucleasas , Humanos , Ratones , RecQ Helicasas , Recombinación Genética , Proteína de Replicación A , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Helicasa del Síndrome de WernerRESUMEN
Using an iron overload mouse model, we explored the protective effect of deferasirox (DFX) and N-acetyl-L-cysteine (NAC) on injured bone marrow hematopoietic stem/progenitor cells (HSPC) induced by iron overload. Mice were intraperitoneally injected with 25 mg iron dextran every 3 days for 4 weeks to establish an iron overload (Fe) model. DFX or NAC were co-administered with iron dextran in two groups of mice (Fe+DFX and Fe+NAC), and the function of HSPCs was then examined. Iron overload markedly decreased the number of murine HSPCs in bone marrow. Subsequent colony-forming cell assays showed that iron overload also decreased the colony forming capacity of HSPCs, the effect of which could be reversed by DFX and NAC. The bone marrow hematopoiesis damage caused by iron overload could be alleviated by DFX and NAC.
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Acetilcisteína/farmacología , Benzoatos/farmacología , Depuradores de Radicales Libres/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Quelantes del Hierro/farmacología , Sobrecarga de Hierro/prevención & control , Sustancias Protectoras/farmacología , Triazoles/farmacología , Animales , Ensayo de Unidades Formadoras de Colonias , Deferasirox , Modelos Animales de Enfermedad , Citometría de Flujo , Hematopoyesis/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Especies Reactivas de Oxígeno/análisis , Valores de Referencia , Reproducibilidad de los Resultados , Factores de Tiempo , Resultado del TratamientoRESUMEN
Werner syndrome (WS) is an autosomal recessive disease characterized by early onset of many features of aging, by an unusual spectrum of cancers, and by genomic instability. The WS protein (WRN) possesses 3'-->5' DNA helicase and associated ATPase activities, as well as 3'-->5' DNA exonuclease activity. Currently, WRN is the only member of the widely distributed RecQ DNA helicase family with documented exonuclease activity. It is not known whether deficiency of the exonuclease or helicase/ATPase activities of WRN, or all of them, is responsible for various elements of the WS phenotype. WRN exonuclease has limited homology to Escherichia coli RNaseD, a tRNA processing enzyme. We show here that WRN preferentially degrades synthetic DNA substrates containing alternate secondary structures, with an exonucleolytic mode of action suggestive of RNaseD. We present evidence that structure-dependent binding of WRN to DNA requires ATP binding, while DNA degradation requires ATP hydrolysis. Apparently, the exonuclease and ATPase act in concert to catalyze structure-dependent DNA degradation. We propose that WRN protein functions as a DNA processing enzyme in resolving aberrant DNA structures via both exonuclease and helicase activities.
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ADN Helicasas/metabolismo , ADN/química , ADN/metabolismo , Exonucleasas/metabolismo , Conformación de Ácido Nucleico , Síndrome de Werner/enzimología , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , ADN/genética , ADN de Cadena Simple/química , ADN de Cadena Simple/genética , ADN de Cadena Simple/metabolismo , Activación Enzimática , Exodesoxirribonucleasas , Humanos , RecQ Helicasas , Especificidad por Sustrato , Moldes Genéticos , Helicasa del Síndrome de WernerRESUMEN
Angiosarcoma also called malignant hemangioendothelioma, caused by vascular endothelial cells or in the direction of vascular endothelial cell differertiation of mesenchymal malignant tumor, is a rare tumor found in clinical, can be in any place of the body, such as head and neck, skin and tissue, breast, bone, liver and other organs and so on, also in the nose, and sinuses rich blood vessels. But this tumor has a low incidence in the nose. Because the nose and sinuses location is hidden, the patient often with nasal bleeding, stuffy nose, headache and so on. With the increase of tumor involvement, the patient can appears the symptoms of corresponding adjacent tissue. Therefore this tumor is difficult to be early detected timely. Early complete surgical excision and supplemented by radiotherapy are preferred methods as the treatments of the nasal and sinuses angiosarcoma without distant metastase.