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Acute kidney injury (AKI) is defined as sudden loss of renal function characterized by increased serum creatinine levels and reduced urinary output with a duration of 7 days. Ferroptosis, an iron-dependent regulated necrotic pathway, has been implicated in the progression of AKI, while ferrostatin-1 (Fer-1), a selective inhibitor of ferroptosis, inhibited renal damage, oxidative stress and tubular cell death in AKI mouse models. However, the clinical translation of Fer-1 is limited due to its lack of efficacy and metabolic instability. In this study we designed and synthesized four Fer-1 analogs (Cpd-A1, Cpd-B1, Cpd-B2, Cpd-B3) with superior plasma stability, and evaluated their therapeutic potential in the treatment of AKI. Compared with Fer-1, all the four analogs displayed a higher distribution in mouse renal tissue in a pharmacokinetic assay and a more effective ferroptosis inhibition in erastin-treated mouse tubular epithelial cells (mTECs) with Cpd-A1 (N-methyl-substituted-tetrazole-Fer-1 analog) being the most efficacious one. In hypoxia/reoxygenation (H/R)- or LPS-treated mTECs, treatment with Cpd-A1 (0.25 µM) effectively attenuated cell damage, reduced inflammatory responses, and inhibited ferroptosis. In ischemia/reperfusion (I/R)- or cecal ligation and puncture (CLP)-induced AKI mouse models, pre-injection of Cpd-A1 (1.25, 2.5, 5 mg·kg-1·d-1, i.p.) dose-dependently improved kidney function, mitigated renal tubular injury, and abrogated inflammation. We conclude that Cpd-A1 may serve as a promising therapeutic agent for the treatment of AKI.
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Lesión Renal Aguda , Ferroptosis , Ratones Endogámicos C57BL , Fenilendiaminas , Animales , Ferroptosis/efectos de los fármacos , Lesión Renal Aguda/tratamiento farmacológico , Lesión Renal Aguda/metabolismo , Ratones , Masculino , Fenilendiaminas/farmacología , Fenilendiaminas/uso terapéutico , Ciclohexilaminas/farmacología , Ciclohexilaminas/uso terapéutico , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/metabolismo , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismoRESUMEN
Gastrin-releasing peptide (GRP) binds to its receptor (GRP receptor [GRPR]) to regulate multiple biological processes, but the function of GRP/GRPR axis in acute kidney injury (AKI) remains unknown. In the present study, GRPR is highly expressed by tubular epithelial cells (TECs) in patients or mice with AKI, while histone deacetylase 8 may lead to the transcriptional activation of GRPR. Functionally, we uncovered that GRPR was pathogenic in AKI, as genetic deletion of GRPR was able to protect mice from cisplatin- and ischemia-induced AKI. This was further confirmed by specifically deleting the GRPR gene from TECs in GRPRFlox/Flox//KspCre mice. Mechanistically, we uncovered that GRPR was able to interact with Toll-like receptor 4 to activate STAT1 that bound the promoter of MLKL and CCL2 to induce TEC necroptosis, necroinflammation, and macrophages recruitment. This was further confirmed by overexpressing STAT1 to restore renal injury in GRPRFlox/Flox/KspCre mice. Concurrently, STAT1 induced GRP synthesis to enforce the GRP/GRPR/STAT1 positive feedback loop. Importantly, targeting GRPR by lentivirus-packaged small hairpin RNA or by treatment with a novel GRPR antagonist RH-1402 was able to inhibit cisplatin-induced AKI. In conclusion, GRPR is pathogenic in AKI and mediates AKI via the STAT1-dependent mechanism. Thus, targeting GRPR may be a novel therapeutic strategy for AKI.
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Lesión Renal Aguda , Cisplatino , Animales , Ratones , Cisplatino/efectos adversos , Necroptosis , Lesión Renal Aguda/metabolismo , Riñón/metabolismo , Inflamación/metabolismo , Ratones Endogámicos C57BLRESUMEN
OBJECTIVES: We examined racial/ethnic differences in the association between influenza vaccine recommendations from healthcare providers and maternal vaccination uptake. METHODS: This cross-sectional study examined data from the Pregnancy Risk Assessment Monitoring System. We categorized respondents as non-Hispanic (NH) Whites, NH-Blacks, NH-Asians, American Indians/Alaska Natives, NH Other non-Whites, and Hispanics. We conducted multivariable logistical regression models to evaluate adjusted odds ratios (AOR) and 95% confidence intervals (CI). Covariates included maternal age, marital status, education, insurance status before pregnancy, the number of previous live births, the number of prenatal care visits, and smoking status during pregnancy. RESULTS: The prevalences of receiving influenza vaccine recommendations from healthcare providers and maternal vaccine were 80.01% and 50.42%, respectively. NH-Blacks are less likely to receive provider recommendations (AOR = 0.82; 95%CI 0.77-0.87) and be vaccinated (AOR = 0.76; 95%CI 0.72-0.80) than NH-Whites. Receiving provider recommendations was significantly associated with increased maternal influenza vaccine uptake (AOR = 15.50; 95% CI 14.51-16.55). The associations were significant for all racial/ethnic groups, with the highest among NH-Asians (AOR = 22.04; 95% CI 17.88-27.16) and the lowest among NH Other non-Whites (AOR = 11.07; 95% CI 8.25-14.86). Within NH-Asians, effectiveness among Chinese was highest (AOR = 29.39; 95% CI 18.10-47.71). CONCLUSIONS: Racial/ethnic disparities in maternal influenza vaccine uptake and receiving vaccine recommendations from healthcare providers persisted. Further studies on the racial/ethnic disparities in maternal vaccination were warranted and tailored strategies are required to reduce this health disparity.
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Vacunas contra la Influenza , Gripe Humana , Adolescente , Adulto , Femenino , Humanos , Embarazo , Adulto Joven , Estudios Transversales , Etnicidad , Personal de Salud , Disparidades en Atención de Salud/etnología , Disparidades en Atención de Salud/estadística & datos numéricos , Gripe Humana/prevención & control , Gripe Humana/etnología , Complicaciones Infecciosas del Embarazo/prevención & control , Complicaciones Infecciosas del Embarazo/etnología , Atención Prenatal/estadística & datos numéricos , Estados Unidos , Vacunación/estadística & datos numéricos , Grupos RacialesRESUMEN
BACKGROUND: Effective response and reducing the burden of family care for children with cancer is critical, and China currently lacks a specific assessment tool. AIMS: This study aimed to translate and validate the Caregiving Burden Scale for Family Caregivers of Children with Cancer (CBSFC-CC) and then test and implement the tool. METHODS: According to the Beaton cross-cultural debugging guide, preliminary Chinese version of CBSFC-CC scale was formed, which was suitable for Chinese language environment and clinical context. Exploratory factor analyses (EFA) and confirmatory factor analyses (CFA) were performed to verify structural validity. Convergent validity, discriminant validity and reliability were also conducted. RESULTS: A total of 529 family caregivers of children with cancer participated in the survey. EFA extracts and combines four factors and explained 65.80% of the total variation. CFA proved that all the goodness-of-fit indicators were acceptable. The Cronbach's alpha of the Chinese version of CBSFC-CC was .96, and the test-retest reliability coefficient was .95. Four dimensions and 29 items were identified in the final Chinese version of CBSFC-CC. CONCLUSION: The chinese version CBSFC-CC is scientifically reasonable and has good reliability and validity, which can be applied to the investigation of the nursing burden of family caregivers of children with cancer in China.
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The development of practical and efficient electromagnetic wave (EMW) absorbing materials is a challenging research problem. A mussel-inspired molecular structure regulation strategy using polydopamine to increase the roughness and functional groups of basalt fiber (BF) surface, which can improve the fiber interfacial adhesion. Herein, a novel BF-Fe3O4/CNTs heterostructure is synthesized through a dip-coating adsorption process. The three-dimensional network structure of Fe3O4/CNTs hybridin situanchored on the surface of BF, which endows the composite to have good intrinsic magnetic and dielectric properties. Modulation of EMW absorption performance by controlling the addition of CNTs, the minimum RL of BF-Fe3O4/7C reaches to -40.57 dB at a thickness of 1.5 mm with CNTs addition of 7%. The enhanced EMW absorption performance of BF-Fe3O4/7C heterostructure may be attributed to the synergistic effects of interfacial polarization between the hollow magnetic Fe3O4spheres and CNTs, conduction loss, magnetic resonance loss and multiple reflection/scattering inside the BF. This work provides a simple pathway to design EMW absorbing materials with good environmental stability.
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BACKGROUND: We developed an algorithm to quantitatively estimate endotoxin exposure for farmers in the Biomarkers of Exposure and Effect in Agriculture (BEEA) Study. METHODS: The algorithm combined task intensity estimates derived from published data with questionnaire responses on activity duration to estimate task-specific cumulative endotoxin exposures for 13 tasks during four time windows, ranging from "past 12 months" to "yesterday/today." We applied the algorithm to 1681 participants in Iowa and North Carolina. We examined correlations in endotoxin metrics within- and between-task. We also compared these metrics to prior day full-shift inhalable endotoxin concentrations from 32 farmers. RESULTS: The highest median task-specific cumulative exposures were observed for swine confinement, poultry confinement, and grind feed. Inter-quartile ranges showed substantial between-subject variability for most tasks. Time window-specific metrics of the same task were moderately-highly correlated. Between-task correlation was variable, with moderately-high correlations observed for similar tasks (e.g., between animal-related tasks). Prior day endotoxin concentration increased with the total metric and with task metrics for swine confinement, clean other animal facilities, and clean grain bins. SIGNIFICANCE: This study provides insight into the variability and sources of endotoxin exposure among farmers in the BEEA study and summarizes exposure estimates for future investigations in this population.
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Contaminantes Ocupacionales del Aire , Exposición Profesional , Humanos , Animales , Porcinos , Endotoxinas/análisis , Contaminantes Ocupacionales del Aire/análisis , Polvo/análisis , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Agricultura , Algoritmos , BiomarcadoresRESUMEN
BACKGROUND/OBJECTIVE: Farmers conduct numerous tasks with potential for endotoxin exposure. As a first step to characterize endotoxin exposure for farmers in the Biomarkers of Exposure and Effect in Agriculture (BEEA) Study, we used published data to estimate task-specific endotoxin concentrations. METHODS: We extracted published data on task-specific, personal, inhalable endotoxin concentrations for agricultural tasks queried in the study questionnaire. The data, usually abstracted as summary measures, were evaluated using meta-regression models that weighted each geometric mean (GM, natural-log transformed) by the inverse of its within-study variance to obtain task-specific predicted GMs. RESULTS: We extracted 90 endotoxin summary statistics from 26 studies for 9 animal-related tasks, 30 summary statistics from 6 studies for 3 crop-related tasks, and 10 summary statistics from 5 studies for 4 stored grain-related tasks. Work in poultry and swine confinement facilities, grinding feed, veterinarian services, and cleaning grain bins had predicted GMs > 1000 EU/m3 . In contrast, harvesting or hauling grain and other crop-related tasks had predicted GMs below 100 EU/m3 . SIGNIFICANCE: These task-specific endotoxin GMs demonstrated exposure variability across common agricultural tasks. These estimates will be used in conjunction with questionnaire responses on task duration to quantitatively estimate endotoxin exposure for study participants, described in a companion paper.
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Contaminantes Ocupacionales del Aire , Exposición Profesional , Humanos , Animales , Porcinos , Endotoxinas/análisis , Contaminantes Ocupacionales del Aire/análisis , Polvo/análisis , Monitoreo del Ambiente , Exposición por Inhalación/análisis , Exposición Profesional/análisis , Agricultura , AlgoritmosRESUMEN
PURPOSE: This cross-sectional study aimed to estimate the risks of adverse birth outcomes among pregnant smokers and the benefits of smoking cessation during pregnancy on birth outcomes across the United States. METHODS: We performed an analysis of 203,437 pregnant women using data collected by the Pregnancy Risk Assessment Monitoring System (PRAMS) from 2012 to 2017. PRAMS uses questionnaires and birth certificates to collect information about the socio-demographic characteristics of pregnant women, smoking status before and during pregnancy, and birth outcomes. We assessed the relationship between self-reported smoking status during pregnancy and preterm birth, low birth weight, and small-for-gestational-age using multivariable logistic regression models. RESULTS: In our study population, 80.43% of pregnant women never smoked, 10.55% of pregnant women quit smoking during pregnancy, and 9.02% continued smoking during pregnancy. Puerto Rico had the highest prevalence of non-smokers (94.12%), while West Virginia had the lowest prevalence of non-smokers (60.54%). Pregnant women who had a higher education level, were married, had less than 5 types of stress, and had government or private insurance before pregnancy had a higher prevalence of smokers who quit during pregnancy (quit smokers) than those that continued smoking (continuous smokers). Compared to non-smokers, continuous smokers had a significantly higher risk of low birth weight (AOR: 1.91, 95% CI 1.80, 2.03), preterm birth (AOR: 1.31, 95% CI 1.21, 1.41), and small-for-gestational-age (AOR: 2.22, 95% CI 2.07, 2.39). However, the relationships between quitting smoking and preterm birth and small-for-gestational-age were not significant. CONCLUSION: Our models suggest that smoking cessation during pregnancy can prevent adverse birth outcomes by significantly reducing the risk of preterm birth and small-for-gestational-age to almost comparable to not smoking.
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Complicaciones del Embarazo , Nacimiento Prematuro , Cese del Hábito de Fumar , Embarazo , Recién Nacido , Femenino , Humanos , Estados Unidos/epidemiología , Nacimiento Prematuro/epidemiología , Nacimiento Prematuro/etiología , Ciudad de Nueva York , Estudios Transversales , Complicaciones del Embarazo/epidemiología , Retardo del Crecimiento FetalRESUMEN
The usage of flame retardants in flammable polymers has been an effective way to protect both lives and material goods from accidental fires. Phosphorus flame retardants have the potential to be follow-on flame retardants after halogenated variants, because of their low toxicity, high efficiency and compatibility. Recently, the emerging allotrope of phosphorus, two-dimensional black phosphorus, as a flame retardant has been developed. To further understand its performance in flame-retardant efficiency among phosphorus flame retardants, in this work, we built model materials to compare the flame-retardant performances of few-layer black phosphorus, red phosphorus nanoparticles, and triphenyl phosphate as flame-retardant additives in cellulose and polyacrylonitrile. Aside from the superior flame retardancy in polyacrylonitrile, few-layer black phosphorus in cellulose showed the superior flame-retardant efficiency in self-extinguishing, ~1.8 and ~4.4 times that of red phosphorus nanoparticles and triphenyl phosphate with similar lateral size and mass load (2.5~4.8 wt%), respectively. The char layer in cellulose coated with the few-layer black phosphorus after combustion was more continuous and smoother than that with red phosphorus nanoparticles, triphenyl phosphate and blank, and the amount of residues of cellulose coated with the few-layer black phosphorus in thermogravimetric analysis were 10 wt%, 14 wt% and 14 wt% more than that with red phosphorus nanoparticles, triphenyl phosphate and blank, respectively. In addition, although exothermic reactions, the combustion enthalpy changes in the few-layer black phosphorus (-127.1 kJ mol-1) are one third of that of red phosphorus nanoparticles (-381.3 kJ mol-1). Based on a joint thermodynamic, spectroscopic, and microscopic analysis, the superior flame retardancy of the few-layer black phosphorus was attributed to superior combustion reaction suppression from the two-dimensional structure and thermal nature of the few-layer black phosphorus.
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Retardadores de Llama , Fósforo/química , Celulosa/química , Polímeros/químicaRESUMEN
Pesticide dust concentrations in homes have been previously associated with occupational and home/garden use of pesticides, hygiene practices, and other factors. This study evaluated the relationship between self-reported use of 2,4-dichlorophenoxyacetic acid (2,4-D) and house dust concentrations and these factors in the Biomarkers of Exposure and Effect in Agriculture (BEEA) Study, a molecular epidemiologic study of farmers in Iowa and North Carolina. The vacuum dust from the homes of 35 BEEA participants was analyzed for the presence of 2,4-D. Participants provided detailed information on occupational and home/garden pesticide use during the past 12 months and reported household characteristics via questionnaires. Linear regression models were used to examine the association between 2,4-D concentrations and four exposure metrics for occupational use in the last 12 months (yes/no, days since last use, days of use, intensity-weighted days of use), home/garden use (yes/no), as well as several household characteristics. 2,4-D was detected in all homes and was used occupationally by 54% of the participants. In a multi-variable model, compared to homes with no occupational or home/garden 2,4-D use reported in the past 12 months, concentrations were 1.6 (95% confidence interval (CI): 0.5, 4.9) times higher in homes with low occupational 2,4-D use (intensity-weighted days < median) and 3.1 (95% CI: 1.0, 9.8) times higher in homes of participants with high use (≥median intensity-weighted days) (p-trend = 0.06). Similar patterns were observed with other occupational metrics. Additionally, 2,4-D dust concentrations were non-significantly elevated (relative difference (RD) = 1.8, 95% CI: 0.5, 6.2) in homes with home/garden use and were significantly lower in homes that did not have carpets (RD = 0.20, 95% CI: 0.04, 0.98). These analyses suggest that elevated 2,4-D dust concentrations were associated with several metrics of recent occupational use and may be influenced by home/garden use and household characteristics.
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Herbicidas , Exposición Profesional , Plaguicidas , Humanos , Exposición a Riesgos Ambientales/análisis , Herbicidas/análisis , Polvo/análisis , Agricultores , Agricultura , Ácido 2,4-Diclorofenoxiacético/análisis , Exposición Profesional/análisisRESUMEN
Appling an electrochemical catalyst is an efficient strategy for inhibiting the shuttle effect and enhancing the S utilization of Li-S batteries. Carbon-based materials are the most common conductive agents and catalyst supports used in Li-S batteries, but the correlation between the diversity of hybridizations and sulfur reduction reaction (SRR) catalytic activity remains unclear. Here, by establishing two forms of carbon models, i.e., graphitic carbon (GC) and amorphous carbon (AC), we observe that the nitrogen atom doped in the GC possesses a higher local charge density and a lower Gibbs free energy towards the formation of polysulfides than in the AC. And the GC-based electrode consistently inherits considerably enhanced SRR kinetics and superior cycling stability and rate capability in Li-S batteries. Therefore, the function of carbon in Li-S batteries is not only limited as conductive support but also plays an unignorable contribution to the electrocatalytic activities of SRR.
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The novel biomarker, insulin-like growth factor binding protein 7 (IGFBP7), is used clinically to predict different types of acute kidney injury (AKI) and has drawn significant attention as a urinary biomarker. However, as a secreted protein in the circulation of patients with AKI, it is unclear whether IGFBP7 acts as a key regulator in AKI progression, and if mechanisms underlying its upregulation still need to be determined. Here we found that IGFBP7 is highly expressed in the blood and urine of patients and mice with AKI, possibly via a c-Jun-dependent mechanism, and is positively correlated with kidney dysfunction. Global knockout of IGFBP7 ameliorated kidney dysfunction, inflammatory responses, and programmed cell death in murine models of cisplatin-, kidney ischemia/reperfusion-, and lipopolysaccharide-induced AKI. IGFBP7 mainly originated from kidney tubular epithelial cells. Conditional knockout of IGFBP7 from the kidney protected against AKI. By contrast, rescue of IGFBP7 expression in IGFBP7-knockout mice restored kidney damage and inflammation. IGFBP7 function was determined in vitro using recombinant IGFBP7 protein, IGFBP7 knockdown, or overexpression. Additionally, IGFBP7 was found to bind to poly [ADP-ribose] polymerase 1 (PARP1) and inhibit its degradation by antagonizing the E3 ubiquitin ligase ring finger protein 4 (RNF4). Thus, IGFBP7 in circulation acts as a biomarker and key mediator of AKI by inhibiting RNF4/PARP1-mediated tubular injury and inflammation. Hence, over-activation of the IGFBP7/PARP1 axis represents a promising target for AKI treatment.
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Lesión Renal Aguda , Inhibidor Tisular de Metaloproteinasa-2 , Adenosina Difosfato Ribosa , Animales , Biomarcadores , Cisplatino/toxicidad , Inflamación , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Lipopolisacáridos , Ratones , Ratones Noqueados , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Carbon-based single metal atom catalysts (SACs) are being extensively investigated to improve the kinetics of the Li-S redox reaction, which is greatly important for batteries with cell-level energy densities >500 W h kg-1 . However, there are contradictory reports regarding the electrocatalytic activities of the different metal atoms and the role of the metal atom in LiS chemistry still remains unclear. This is due to the complex relationship between the catalytic behavior and the structure of carbon-based SACs. Here, the catalytic behavior and active-site geometry, oxidation state, and the electronic structure of different metal centers (Fe/Co/Ni) embedded in nitrogen-doped graphene, and having similar physicochemical characteristics, are studied. Combining X-ray absorption spectroscopy, density functional theory calculations, and electrochemical analysis, it is revealed that the coordination-geometry and oxidation state of the metal atoms are modified when interacting with sulfur species. This interaction is strongly dependent on the hybridization of metal 3d and S p-orbitals. A moderate hybridization with the Fermi level crossing the metal 3d band is more favorable for LiS redox reactions. This study thus provides a fundamental understanding of how metal atoms in SACs impact LiS redox behavior and offers new guidelines to develop highly active catalytic materials for high-performance LiS batteries.
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Carbono , Metales , Carbono/química , Catálisis , Metales/química , Nitrógeno/química , Oxidación-ReducciónRESUMEN
Building materials that are found in the indoor environment can play an important role in determining indoor air quality. Previous studies have recognized that building materials are potential sinks/sources of indoor volatile organic compounds (VOCs), but their uptake under extremely low concentrations has not been extensively studied. This study has characterized the capacities of various building materials for adsorption of trichloroethylene (TCE), which is a contaminant of significant concern in vapor intrusion scenarios. The capacities of more than 20 building materials were established at a TCE concentration of 1.12 ppbv (and for selected materials at concentrations up to 12.5 ppbv). This was achieved using a thermal desorption method. Room temperature isotherms for glass wool, polyethylene, nylon carpet, drywall, printer paper, leather, and cinderblock were measured. The results showed that the sorptive capacities of the building materials were at nanograms per gram levels; cinderblock had the largest sorption capacity among all the building materials tested and this is believed to indicate that solid carbon content of materials plays a significant role during the sorption process. TCE desorption from selected building materials was also investigated at room temperature and 100°C.
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Because of their high theoretical energy density and low cost, lithium-sulfur (Li-S) batteries are promising next-generation energy storage devices. The electrochemical performance of Li-S batteries largely depends on the efficient reversible conversion of Li polysulfides to Li2S in discharge and to elemental S during charging. Here, we report on our discovery that monodisperse cobalt atoms embedded in nitrogen-doped graphene (Co-N/G) can trigger the surface-mediated reaction of Li polysulfides. Using a combination of operando X-ray absorption spectroscopy and first-principles calculation, we reveal that the Co-N-C coordination center serves as a bifunctional electrocatalyst to facilitate both the formation and the decomposition of Li2S in discharge and charge processes, respectively. The S@Co-N/G composite, with a high S mass ratio of 90 wt %, can deliver a gravimetric capacity of 1210 mAh g-1, and it exhibits an areal capacity of 5.1 mAh cm-2 with capacity fading rate of 0.029% per cycle over 100 cycles at 0.2 C at S loading of 6.0 mg cm-2 on the electrode disk.
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Urban green spaces provide manifold environmental benefits and promote human well-being. Unfortunately, these services are largely undervalued, and the potential of urban areas themselves to mitigate future climate change has received little attention. In this study, we quantified and mapped city-wide aboveground carbon storage of urban green spaces in China's capital, Beijing, using field survey data of diameter at breast height (DBH) and tree height from 326 field survey plots, combined with satellite-derived vegetation index at a fine resolution of 6 m. We estimated the total amount of carbon stored in the urban green spaces to be 956.3 Gg (1 Gg = 109 g) in 2014. There existed great spatial heterogeneity in vegetation carbon density varying from 0 to 68.1 Mg C ha-1 , with an average density of 7.8 Mg C ha-1 . As expected, carbon density tended to decrease with urban development intensity (UDI). Likely being affected by vegetation cover proportion and configuration of green space patches, large differences were presented between the 95th and 5th quantile carbon density for each UDI bin, showing great potential for carbon sequestration. However, the interquartile range of carbon density narrowed drastically when UDI reached 60%, signifying a threshold for greatly reduced carbon sequestration potentials for higher UDI. These findings suggested that urban green spaces have great potential to make contribution to mitigating against future climate change if we plan and design urban green spaces following the trajectory of high carbon density, but we should be aware that such potential will be very limited when the urban development reaches certain intensity threshold.
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Secuestro de Carbono , Cambio Climático , Ecosistema , Urbanización , Beijing , Carbono/análisis , Planificación Ambiental , Monitoreo del Ambiente , Árboles/fisiologíaRESUMEN
Three new proton conductors with simple structures based on isolated olyoxometalate anions as well as protonated imidazole and benzimidazole, namely, NNU-6-8, have been successfully prepared by hydrothermal reaction. We could control the number of proton sources by selecting different types and changing the charges of POM anions. The single crystal sample of NNU-6 along a-axis shows a highest proton conductivity of 1.91×10-2 â S cm-1 , which is two and three orders of magnitude higher than that of 2.42×10-4 and 8.90×10-5 â S cm-1 along b- and c-axes, respectively, due to the more unobstructed H-bonding network and stronger π-π stacking between benzimidazole rings as proton-transferring pathway along a-axis than that along b and c axes. It is a straightforward model to understand the metaphysical proton-conducting process, and this is the first time to put forward the idea that π-π stacking could assist proton transfer and be in favor of proton conduction, which has been demonstrated by calculating potential energy surfaces of proton transfer between benzimidazole molecules.
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It has been suggested that ß2-adrenergic receptor (ß2-AR)-mediated signaling induced by catecholamines regulates the degradation of p53. However, the underlying molecular mechanisms were not known. In the present study, we demonstrated that catecholamines upregulated the expression of silent information regulator 1 (Sirt1) through activating ß2-AR-mediated signaling pathway, since selective ß2-AR antagonist ICI 118, 551 and non-selective ß-blocker proprenolol effectively repressed isoproterenol (ISO)-induced Sirt1 expression. Catecholamines inhibited doxorubicin (DOX)-induced p53 acetylation and transcription-activation activities by inducing the expression of Sirt1. Knockdown of the Sirt1 expression by the specific siRNA remarkably blocked the inhibitory effects of ISO on DOX-induced p53 acetylation. In addition, we demonstrated that catecholamines induced resistance of cervical cancer cells to chemotherapeutics both in vitro and in vivo and that ß2-AR was overexpressed in cervical cancer tissues. Our data suggest that the p53-dependent, chemotherapeutics-induced cytotoxicity in cervical cancer cells may be compromised by catecholamines-induced upregulation of the Sirt1 expression through activating the ß2-AR signaling.
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Resistencia a Antineoplásicos/fisiología , Regulación Neoplásica de la Expresión Génica/fisiología , Receptores Adrenérgicos beta 2/metabolismo , Sirtuina 1/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Neoplasias del Cuello Uterino/metabolismo , Acetilación , Animales , Western Blotting , Catecolaminas/metabolismo , Catecolaminas/farmacología , Línea Celular Tumoral , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Xenoinjertos , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Microscopía Fluorescente , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores Adrenérgicos beta 2/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Regulación hacia ArribaRESUMEN
Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition. Psychological stress has been postulated to affect the clinical symptoms and recurrence of IBD. The exact molecular mechanisms are not fully understood. In the present study, we demonstrate that psychological stress promotes neutrophil infiltration into colon tissues in dextran sulfate sodium (DSS)-induced colitis model. The psychological stress resulted in abnormal expression of the proinflammatory cytokines (IL-1ß, IL-6, IL-17A, and IL-22) and neutrophil chemokines (CXCL1 and CXCL2) and overactivation of the STAT3 inflammatory signaling pathway. Under chronic unpredictable stress, the adrenergic nervous system was markedly activated, as the expression of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, in bone marrow and colonic epithelium was enhanced, especially in the myenteric ganglia. The ß-AR agonist isoproterenol mimicked the effects of psychological stress on neutrophilia, neutrophil infiltration, and colonic damage in DSS-induced colitis. The ß1-AR/ß2-AR inhibitor propranolol reduced the numbers of the neutrophils in the circulation, suppressed neutrophil infiltration into colonic tissues, and attenuated the colonic tissue damage promoted by chronic stress. Propranolol also abolished stress-induced upregulation of proinflammatory cytokines and neutrophil chemokines. Our data reveal a close linkage between the ß1-AR/ß2-AR activation and neutrophil trafficking and also suggest the critical roles of adrenergic nervous system in exacerbation of inflammation and damage of colonic tissues in experimental colitis. The current study provides a new insight into the mechanisms underlying the association of psychological stress with excessive inflammatory response and pathophysiological consequences in IBD. The findings also suggest a potential application of neuroprotective agents to prevent relapsing immune activation in the treatment of IBD.