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We present a framework for studying the spillover effect of negative foreign COVID-19 news on attitudes towards immigration. Our framework proposes that exposure to negative COVID-19 news from foreign countries can activate negative associations with foreigners, reduce positive attitudes towards them, and increase perceived threat, ultimately leading to decreased support for immigration. We conducted three studies to test this framework. Study 1 found that exposure to negative COVID-19 news about a foreign country increased negative valence associations with that country. Study 2 showed that exposure to more negative COVID-19 news about foreign countries was associated with lower acceptance of immigration policies in real life. Study 3 replicated the spillover effect of negative news exposure using a scenario manipulation. The effects of negative news exposure on immigration policy acceptance in both Studies 2 and 3 were mediated by changes in foreigner attitudes and intergroup threat. Our results demonstrate the important spillover effect of negative foreign COVID-19 news exposure on immigration attitudes and highlight the association perspective as a foundation for understanding attitude changes during the COVID-19 pandemic.
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PURPOSE: The rational time for intubation during early mandibular distraction osteogenesis (MDO) in infants is unknown. To investigate the differences in clinical outcomes following MDO before and after a standardized extubation protocol implementation in infants. METHODS: A retrospective cohort study was performed for infant patients under 1 year old undergoing MDO. The study population was composed of all patients presenting for evaluation and management who underwent MDO between November 2016 and February 2021. We divided them into 2 groups: the pre-protocol group and the protocol group. The inpatient charts of infants were assessed. The primary outcome was respiratory events after extubation. The secondary outcomes were duration of mechanical ventilation (MV), postoperative length of stay (LOS), and success rate of the first extubation. Other variables included age, sex, weight, height, and information related to diagnosis, distraction, anesthesia, and operation. The logistic regression model and linear regression model were used to calculate unadjusted and adjusted relative risk (RR) and mean difference (MD) for associations between 2 groups and the primary and secondary outcomes. RESULTS: There were 142 infants in the pre-protocol group and 135 infants in the protocol group. The patients in the protocol group were heavier in weight than those in the pre-protocol group (P<.05). The Cormack-Lehane grade and the duration of operation and anesthesia were higher and longer in the pre-protocol group than in the protocol group (P<.05). Respiratory events after extubation were significantly more common in the pre-protocol group than in the protocol group [21.1 vs. 9.6%, adjusted relative risk 0.46 (95% CI 0.22-0.89), P <.01]. CONCLUSIONS: Among infants undergoing MDO, the standardization of extubation practices can reduce respiratory events after extubation compared with traditional management.
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Extubación Traqueal , Osteogénesis por Distracción , Humanos , Lactante , Mandíbula/cirugía , Respiración Artificial , Estudios RetrospectivosRESUMEN
BACKGROUND: Effective airway management is critical to Pierre Robin Sequence treatment. The goal of this study is to assess the three-dimensional changes in airway size and shape in 117 newborns with isolated Pierre Robin sequence who underwent mandibular distraction osteogenesis. METHODS: During the study period (11/29/2016 to 11/26/2019), 117 newborns affected by isolated Pierre Robin sequence met the inclusion criteria for the present study. All 117 included patients underwent linear distraction. Demographic variables were recorded and analyzed. Cone-beam computed tomography were performed before and after mandibular distraction osteogenesis. A systemic quantitative three-dimensional analysis of size and shape of upper airway was performed. RESULTS: The mean age was 71 day (range 12 to 213). The mean weight was 3.9 kg (range 2.3-6.8). A total of 53 patients are female and 64 are male. When the distraction device was removed, the upper and lower jaws were symmetrically aligned. Pre- and post-distraction comparison clearly showed osteogenesis. For the size of the upper airway, airway volume, anteroposterior dimension of the retroglossal airway, lateral dimension of retroglossal airway, minimum retropalatal area, minimum retroglossal area, average cross-sectional area and minimum cross-sectional area increased significantly after mandibular distraction osteogenesis (P < 0.001). However, the airway length did not change significantly (P > 0.05). For the shape of the upper airway, the lateral/anteroposterior ratio in the retroglossal region and the ratio of the retropalatal airway diameter to the retroglossal airway diameter significantly decreased after mandibular distraction osteogenesis (P < 0.001). The airway uniformity significantly increased after mandibular distraction osteogenesis (P < 0.001). CONCLUSION: Mandibular distraction osteogenesis for isolated Pierre Robin sequence improved size and shape of the upper airway, further confirming mandibular osteogenesis distraction as an effective surgical modality to address the airway obstruction in newborns affected by isolated Pierre Robin sequence. Cone-beam computed tomography scanning and analysis can serve as a safe and effective examination modality for upper airway applications of PRS newborns.
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Obstrucción de las Vías Aéreas , Osteogénesis por Distracción , Síndrome de Pierre Robin , Anciano , Obstrucción de las Vías Aéreas/diagnóstico por imagen , Obstrucción de las Vías Aéreas/cirugía , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Síndrome de Pierre Robin/diagnóstico por imagen , Síndrome de Pierre Robin/cirugía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Airway management is challenging in children with Robin sequence (RS) requiring mandibular distraction osteogenesis (MDO). We derived and validated a prediction rule to identify difficult intubation before MDO for children with RS based on craniofacial computed tomography (CT) images. METHOD: This was a retrospective study of 69 children with RS requiring MDO from November 2016 to June 2018. Multiple CT imaging parameters and baseline characteristic (sex, age, gestational age, body mass index [BMI]) were compared between children with normal and difficult intubation according to Cormack-Lehane classification. A clinical prediction rule was established to identify difficult intubation using group differences in CT parameters (eleven distances, six angles, one section cross-sectional area, and three segment volumes) and clinicodemographic characteristics. Predictive accuracy was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: The overall incidence of difficult intubation was 56.52%, and there was no significant difference in sex ratio, age, weight, height, BMI, or gestational age between groups. The distance between the root of the tongue and posterior pharyngeal wall was significantly shorter, the bilateral mandibular angle shallower, and the cross-sectional area at the epiglottis tip smaller in the difficult intubation group. A clinical prediction rule based on airway cross-sectional area at the tip of the epiglottis was established. Area > 36.97 mm2 predicted difficult intubation while area < 36.97 mm2 predicted normal intubation with 100% sensitivity, 62.5% specificity, 78.6% positive predictive value, and 100% negative predictive value (area under the ROC curve = 0.8125). CONCLUSION: Computed tomography measures can objectively evaluate upper airway morphology in patients with RS for prediction of difficult intubation. If validated in a larger series, the measures identified could be incorporated into airway assessment tools to guide treatment decisions. This was a retrospective study and was granted permission to access and use these medical records by the ethics committee of Guangzhou Women and Children's Medical Center. TRIALS REGISTRATION: Registration No. ChiCTR1800018252, NaZhang, Sept 7 2018.
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Manejo de la Vía Aérea/métodos , Mandíbula/cirugía , Osteogénesis por Distracción/métodos , Síndrome de Pierre Robin/cirugía , Reglas de Decisión Clínica , Femenino , Humanos , Lactante , Intubación Intratraqueal/métodos , Masculino , Mandíbula/anomalías , Mandíbula/diagnóstico por imagen , Síndrome de Pierre Robin/diagnóstico por imagen , Estudios Retrospectivos , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos XRESUMEN
PURPOSE: The characteristics of postoperative fever after cleft repair surgery in children are unknown. Thus, the purpose of this study was to determine the incidence of and risk factors for postoperative fever. DESIGN AND METHODS: We retrospectively assessed 328 children who underwent cleft surgery at our hospital between March 2016 and April 2017 and were followed up for at least 3â¯days postoperatively. Fever was defined as a body temperature ≥38.0 °C. RESULTS: Seventy-one percent (nâ¯=â¯233) of patients developed fever within 72â¯h postoperatively, and most cases of postoperative fever were benign. Patients most frequently developed fever within 24â¯h postoperatively, and the occurrence of fever significantly decreased between 24 and 72â¯h postoperatively (pâ¯<â¯0.001). The incidence of fever with temperatures between 38.0 °C and 39.0 °C was higher than that of fever with temperatures ≥39.0 °C (pâ¯<â¯0.001). The mean duration of an episode of fever was 4â¯h. The type of surgery, method of anesthesia, and duration of anesthesia and surgery were found to be correlated with postoperative fever after cleft surgery. CONCLUSIONS: Most cases of postoperative fever after cleft surgery were benign occurrences. Postoperative fever after cleft repair surgery was characterized by a low grade, an early onset and a short duration in children. The method of anesthesia, duration of surgery and duration of anesthesia were risk factors for postoperative fever. PRACTICE IMPLICATIONS: Our results could help healthcare providers to gain increased knowledge of the risk factors for fever and when and how to treat postoperative fever.
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Anestesia/efectos adversos , Fisura del Paladar/cirugía , Fiebre/etiología , Cuidados Posoperatorios/métodos , Complicaciones Posoperatorias/etiología , Anestesia/métodos , Niño , Preescolar , Femenino , Fiebre/prevención & control , Humanos , Lactante , Masculino , Complicaciones Posoperatorias/prevención & control , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Microwave absorbers are usually designed to solve electromagnetic interferences at a specific frequency, while the requirements may be dynamic during service life. Therefore, a recoverable tuning for microwave absorption properties in response to an external stimulus would be highly desirable. We herein present a micro/nano-scale hybrid absorber, in which high-performance Fe@C nanocapsule absorbents are integrated with a porous melamine sponge skeleton, exhibiting multiple merits of light weight, strong absorption and high elasticity. By mechanically compressing and decompressing the absorber, microwave absorption performances can be effectively shifted between 18 GHz and 26.5 GHz. The present study thus provides a new strategy for the design of a 'dynamic' microwave absorber.
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Mandibular Distraction Osteogenesis (MDO) is now the preferred procedure to alleviate airway obstruction in infants with severe Robin Sequence (RS). However, there have been very few studies investigating complications related to MDO surgery performed on patients affected by isolated RS. In this study, age at distraction, weight at distraction, preoperative intubation, repeat MDO and complications associated with MDO were included as variables. Minor, moderate and major problems were evaluated and recorded as surgical site infections (SSI), injuries to the facial nerve, self-extinction hypertrophic scars, temporomandibular joint ankylosis, device failures, early ossification and fibrous non-union. One hundred and fifty one patients with isolated RS were included. At distraction, the mean age was 72 days (12-540 days) and the mean weight was 4.05 kg (2.4-12.2 kg). Only one patient needed tracheostomy after MDO, and none required further distraction. Ultimately, the complication rate was 15.23%, and there was a total of 7.95% minor, 9.27% moderate and 0% major complications. Minor incidents included surgical site infection (SSI) managed with antibiotics taken orally (n = 8), neuropraxia in the VII cranial nerve (CN) (n = 1), and hypertrophic scarring (n = 3). Incidents reported as moderate were SSIs managed with intravenous antibiotics (n = 9), incision and drainage (n = 3) and self-extubation (n = 2). There was no case of TMJ ankylosis. There were no cases of early or premature ossification, fibrous non-union and device fracture. In conclusion, MDO is an effective and appropriate management technique for infants with isolated RS and severe airway obstruction. Infections at the surgery site accounted for the vast majority of the complications. Further investigations may be needed to determine the long-term consequences of MDO.
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All-printed flexible micro-supercapacitors (MSCs) based on two-dimensional (2D) nanomaterials with in-plane interdigital configurations are regarded as promising miniaturized power source units, but they chronically suffer from self-aggregation and inadequate matching of electrode materials, thus resulting in inefficient electrolyte ions intercalation. Herein, an innovative multicomponent interlaced architecture essentially consisting of 2-amino-8-naphthol 6-sulfonic acid (ANS)-anchored pristine graphene and highly conductive multiwalled carbon nanotubes is reported. The assembled and optimized Gr@ANS electrodes offer sufficient absorption/desorption and redox-active sites, delivering a high areal capacitance of 33.7 mF/cm2 for screen-printed MSCs. Particularly, the well-modified Gr@ANS/CNTs-interlaced complex structure effectively prevents the usual restacking of the delaminated Gr@ANS nanosheets and maximizes ion accessibility in electrodes. Ascribed to the optimized electron-transferring kinetics, the achieved Gr@ANS/CNTs MSCs exhibit excellent capacitance (40.2 mF/cm2 and 18.8 F/cm3), simultaneously significantly increasing the rate capability of Gr@ANS MSCs (from 3.9 to 60.0%). Arising from the multicomponent synergism, the all-solid-state MSCs exhibit outstanding bending stability and cycling performance (73.8% after 10â¯000 charge/discharge cycles). The new charge reservoir engineering evidenced in graphene-based micro-supercapacitors would serve as a stepping stone toward the scalable manufacture of hybrid energy storage micro-devices.
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Background: Impaired weight gain is prevalent in Robin Sequence (RS) newborns. Although mandibular distraction osteogenesis (MDO) has been proven to improve oral feeding, its impact on postoperative weight gain remains unclear. The purpose of this study is to explore whether MDO can help RS babies reach a normal weight, as well as the effect of MDO timing on weight velocity. Methods: One hundred infants with severe RS and one hundred with normal controls met the inclusion criteria for the study. Included patients underwent MDO. Weights at different timing points were recorded and analyzed and compared to normal controls. Results: After the distractor removal weights of patients undergoing MDO at <1 month and 1−2 months were close to the normal control (6.81 ± 0.93 kg versus 7.18 ± 0.61 kg, p = 0.012, and 6.82 ± 0.98 kg versus 7.37 ± 0.75 kg, p = 0.033, respectively), the weights of patients undergoing MDO at 2−3 months and 3−4 months still lagged behind (7.56 ± 1.29 kg versus 8.20 ± 0.61 kg, p = 0.000206 and 7.36 ± 1.05 kg versus 8.25 ± 0.77 kg, p = 0.004, respectively). The weights of all RS infants undergoing MDO showed no significant difference compared to the controls when they aged to 1 year (9.34 ± 0.99 kg versus 9.55 ± 0.45 kg, p = 0.254 for MDO at <1 month; 9.12 ± 0.91 kg versus 9.33 ± 0.46 kg, p = 0.100 for MDO at 1 to 2 months; 9.38 ± 0.29 kg versus 9.83 ± 0.53 kg, p = 0.098 for MDO at 2 to 3 months; and 9.38 ± 0.29 kg versus 9.83 ± 0.53 kg, p = 0.098 for MDO at 3 to 4 months). Conclusion: The MDO procedure helped patients with severe RS to reach a normal weight; and MDO intervention was recommended at an early stage for early weight gain.
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The cancer-testis antigen A-kinase anchor protein 3 (AKAP3) has been shown to have a strong association with breast cancer (BC). However, its role in BC progression received scant attention. We aimed to explore the prognostic implication of aberrant AKAP3 expression for a better knowledge of BC progression and improved treatment. AKAP3 expression was quantitated using tissue microarrays and immunohistochemistry (IHC). Cell viability, invasion, migration, apoptosis, and expressions of PTEN/PI3K/AKT/mTOR signaling components were assessed in AKAP3-overexpressed or si-AKAP3-transfected BC cells. Finally, elevated AKAP3 expression was observed in BC versus paracancerous tissues. BC patients with high AKAP3 expression showed a worse prognosis than low expression patients (P < 0.0001). AKAP3 overexpressions fueled cell growth, proliferation, migration, and invasion in HCC1937 and MDA-MB-468 BC cell lines, alongside increased expressions of PI3K/AKT/mTOR signaling components and PTEN suppression. These effects were pronouncedly reversed, together with elevated apoptosis, in cells transfected with si-AKAP3. Therefore, AKAP3 is upregulated in BC and promotes BC cell growth, invasion, and migration via PTEN/PI3K/AKT/mTOR signaling activation. It may serve as a prognosis indicator for BC survival.
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Proteínas de Anclaje a la Quinasa A , Neoplasias de la Mama , Proteínas Proto-Oncogénicas c-akt , Proteínas de Anclaje a la Quinasa A/genética , Proteínas de Anclaje a la Quinasa A/metabolismo , Apoptosis/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Femenino , Humanos , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Background: After mandibular distraction osteogenesis (MDO), most infants with Pierre Robin sequence (PRS) require mechanical ventilation to assist their breathing. However, the optimal duration of intubation during early mandibular distraction osteogenesis activation is poorly understood. This retrospective study was carried out to identify perioperative risk factors of prolonged mechanical ventilation in infants undergoing MDO. Methods: A total of 95 infants with PRS underwent MDO at Guangzhou Women and Children's Medical Center between 2016 and 2018, and the clinical records of 74 infants who met the selection criteria were analyzed. Of the 74 infants, 26 (35.1%) underwent prolonged mechanical ventilation, 48 (64.9%) did not. t-test, Wilcoxon Sum Rank test or chi-squared test were performed to compare variables that might associate with prolonged mechanical ventilation between the two groups, and then, significant variables identified were included in the multivariate logistic regression model to identify independent variables. Results: Univariate logistic regression analysis revealed that age, preoperative gonial angle, and postoperative pulmonary infection were associated with prolonged mechanical ventilation (all P < 0.05). Multivariate logistic regression analysis confirmed that the preoperative gonial angle and postoperative pulmonary infection were independent risk factors of prolonged mechanical ventilation (both P < 0.05). Conclusions: Infants with PRS and smaller preoperative gonial angle or postoperative pulmonary infection may be more likely to undergo prolonged mechanical ventilation after MDO. For others, extubation may be attempted within 6 days after MDO.
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Pierre Robin sequence (PRS) is a congenital malformation characterized by micrognathia, glossocoma, and mechanical obstruction of the upper respiratory tract. These deformities impair respiration, sleep, feeding, and swallowing, and can lead to malnutrition, stunted development, and death. Bilateral mandibular distraction osteogenesis, whereby the mandible and tongue root are extended outward, is the standard treatment to relieve upper airway obstruction in severe PRS. Accurate placement of the distraction device is essential but challenging, especially in infants, and requires the pre-operative fabrication of surgical guides based on CT images. Three-dimensional (3D) printing allows for the accurate recreation of objects from digitized models. We compared surgical efficacy and safety of bilateral mandibular distraction osteogenesis using 3D printed or traditionally fabricated surgery guides for treatment of infants with severe PRS.During the period from 2014 to 2016, 22 patients with severe PRS were treated using either traditional or 3D printed surgery guides. We compared outcome measures of operations, including intraoperative bleeding, operation time, and postoperative complications.The 3D printed surgery guide group demonstrated significantly shorter operation time (Pâ<.05) as well as moderately shorter hospital stay and artificial ventilation time (â¼1 day less). Furthermore, despite markedly younger average age of the 3D printed group (1.3 vs 3.5 months), there was no increase in postoperative complications using the 3D printed guides.Three-dimensional printed surgery guides were used successfully for bilateral mandibular traction osteogenesis, and according to several outcome, parameters demonstrated superior efficacy and safety compared to traditional guides. Further research is warranted to extend the applications of 3D printed surgical guides for craniofacial surgery.
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Mandíbula/cirugía , Osteogénesis por Distracción/instrumentación , Síndrome de Pierre Robin/cirugía , Impresión Tridimensional , Femenino , Humanos , Lactante , Tiempo de Internación , Masculino , Mandíbula/diagnóstico por imagen , Osteogénesis por Distracción/métodos , Síndrome de Pierre Robin/diagnóstico por imagen , Medicina de Precisión/instrumentación , Respiración Artificial , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
Mandibular distraction osteogenesis (MDO) is an effective treatment for tongue-based airway obstruction in infants with severe Pierre Robin sequence (PRS). Most infants receiving MDO require postoperative mechanical ventilation (MV) to assist breathing. Optimal MV time for each individual patient and factors influencing the time must be identified to guide clinical decision-making.A retrospective analysis was performed on 75 infants with PRS receiving MDO from November 2016 to August 2018. Twenty-six were females and 47 were males. Data extracted from the hospital information system included sex, age, weight, history of preterm labor, preoperative pulmonary infection, laryngomalacia/tracheomalacia, laryngoscope exposure classification, anesthesia duration, operation duration, postoperative treatment site, situation of distraction, postoperative complications and MV duration. Statistical analyses were conducted to investigate the potential associations of these factors with MV time.Seventy-three PRS syndrome patients received anesthesia for MDO device procedures were considered eligible for study. Patient sex, history of preterm labor, preoperative pulmonary infection, laryngomalacia/tracheomalacia, laryngoscopy exposure difficulty, postoperative treatment site (neonatal or pediatric intensive care unit), ventilator-associated pneumonia, age, weight, anesthesia duration, and operation duration had no significant influence on postsurgical MV time (Pâ>â.05). Amount of distraction at the time of extubation had statistically significant influence on postoperative MV time (Pâ<â.05). In addition, scatter plots revealed linear relationships between postoperative MV time and amount of distraction at extubation.According to this analysis, amount of distraction was associated with MV time following MDO for severe PRS and roughly 6 days post-surgery is a generally safe extubation time.
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Obstrucción de las Vías Aéreas/terapia , Mandíbula , Osteogénesis por Distracción , Síndrome de Pierre Robin/complicaciones , Respiración Artificial , Extubación Traqueal , Obstrucción de las Vías Aéreas/etiología , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , Factores de TiempoRESUMEN
Recent studies showed that sulfidated nano zerovalent iron (S-nZVI) is a better alternative to non-sulfidated nano zerovalent iron (NS-nZVI) commonly used for contaminated site remediation. However, its reactivity with different halogenated pollutants such as tetrabromobisphenol A (TBBPA) remains unclear. In this study, we explored the reductive transformation of TBBPA by S-nZVI and compared it with that by NS-nZVI. The results showed that over 90% of the initial TBBPA (20 mg L(-1)) was transformed by S-nZVI within 24 h of reaction, which was 1.65 times as high as that for NS-nZVI. The TBBPA transformation by S-nZVI was well described by a pseudo-first-order kinetic model, whilst that by NS-nZVI was well fitted by a three-parameter single exponential decay model. After 11 weeks of aging, S-nZVI was still able to transform up to 56% of the initial TBBPA within 24 h of reaction; by contrast, the two-week aged NS-nZVI lost more than 95% of its original capacity to transform TBBPA. Moreover, S-nZVI showed only an approximately 20% decrease in its capacity to transform TBBPA in the seventh cycle, while NS-nZVI was no longer able to transform TBBPA in the fourth cycle. XPS analysis suggested the formation of FeS layer on S-nZVI surface and electrochemical analysis revealed an elevated electron transfer capacity of S-nZVI, which were likely responsible for the superior performances of S-nZVI in TBBPA transformation. While the transformation rate of TBBPA by S-nZVI decreased with increasing initial concentration of TBBPA, it showed an increasing trend with increasing S/Fe ratio and initial concentration of S-nZVI. The study indicated that S-nZVI has the potential to be a promising alternative to NS-nZVI for remediation of TBBPA-contaminated aquatic environments.
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Hierro , Contaminantes del Agua/química , CinéticaRESUMEN
Melanotic neuroectodermal tumor of infancy (MNTI) is a rare, fast-growing, benign tumor originating from the neural crest. The tumor most often occurs during the first year of life. The predilection site of MNTI is the anterior maxilla, whereas lesions of the mandible are uncommon and account for only 6% of all cases. At present, the most common treatment for MNTI is surgical resection, however, tumor recurrence arises in 10-60% of cases. The optimal extent of surgical resection is a matter of debate; rapid growth and the possibilities of malignant transformation and metastasis indicate aggressive surgical resection. However, extensive resection may interfere with post-operative growth and development. The procedure should therefore preserve as much of the surrounding tissue as possible. The present case study examines a rare case of right-sided mandibular MNTI in a two-month-old female. The association between the tumor and the surrounding sclerotin, affected dental germ and the condition of the inferior alveolar nerve, were observed during the operative and post-operative periods. In addition, previous cases of MNTI were reviewed to evaluate the optimal scope of surgical resection.
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Hydrometallurgy is an acid leaching based process widely used for recovering precious metals from electronic wastes (e-wastes). The effects of acid leaching on the fate of brominated flame retardants (BFRs) in typical hydrometallurgical processes remain largely unknown. This study was aimed at evaluating the fate of tetrabromobisphenol A (TBBPA), a commonly used BFR, in three acid leaching reagents (i.e. H2SO4, HNO3, and HCl) commonly used in hydrometallurgy. It was found that the reactions of TBBPA with concentrated H2SO4 followed a pseudo-zero-order rate and the reaction rates declined rapidly as the concentrations of H2SO4 decreased. In contrast, TBBPA could be easily transformed in less concentrated HNO3 solutions (<21.7 wt%) and the reactions followed a pseudo-first-order rate. The reaction products identified by GC-MS indicated different transformation pathways of TBBPA in H2SO4 and HNO3. HCl or HCl/H2SO4 mixtures (3:1, v/v) did not appear to react with TBBPA, while aqua regia (3:1 HCl/HNO3, v/v) reacted violently with TBBPA and led to almost complete disappearance of TBBPA within a minute. It suggested that HNO3 significantly affected the fate of TBBPA and the use of HNO3 as leaching reagents in hydrometallurgy of e-wastes should be carefully evaluated. Collectively, our findings of distinct fate of TBBPA in different acid leaching reagents provided fundamental information for design of hydrometallurgical treatment of e-wastes to minimize acid reactions with BFRs within plastics matrix and to maximize acid leaching efficiency for metals recycling processes.
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Residuos Electrónicos , Retardadores de Llama , Ácido Clorhídrico/química , Ácido Nítrico/química , Bifenilos Polibrominados/química , Ácidos Sulfúricos/química , Cinética , Administración de Residuos/métodosRESUMEN
Novel dynamic equipment with gas in and out continuously was developed to study the capture capacity of CO(2). Municipal solid waste incineration (MSWI) fly ash has a high capture rate of CO(2) in CO(2)-rich gas. Fly ash can sequester pure CO(2) rapidly, and its capacity is 16.3 g CO(2)/100 g fly ash with no water added and 21.4 g CO(2)/100 g fly ash with 20% water added. For simulated incineration gas containing 12% CO(2), the capture rate decreased and the capacity was 13.2 g CO(2)/100 g fly ash with no water added and 18.5 g CO(2)/100 g fly ash with 20% water added. After accelerated carbonation, the C and O contents increased, indicating CO(2) capture in the fly ash; CO(2) combines with Ca(OH)(2) to form CaCO(3), which increased the CaCO(3) content from 12.5 to 54.3%. The leaching of Pb markedly decreased from 24.48 to 0.111 mg/L.
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Dióxido de Carbono/química , Ceniza del Carbón/química , Incineración/instrumentación , Eliminación de ResiduosRESUMEN
Ultrasonic generating trough was applied to study the impact of ultrasonic on conditioning of sewage sludge. There are few ultrasonic generators for sludge treatment specifically, so we designed a double-frequency ultrasonic generating trough which could adjust frequency, energy density and treating time flexibly. In the research characteristics of sewage sludge treated by single-frequency and double-frequency ultrasonic were compared. According to the results, the digestion biogas of the sewage sludge treated by ultrasonic increase obviously, and the digestion biogas increment of the sewage sludge treated by single-frequency is 40.93%, higher than that treated by double-frequency. But the SCOD of the sewage sludge treated by double-frequency is 23.5%, more than that treated by single-frequency.
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Aguas del Alcantarillado/química , Ultrasonido , Eliminación de Residuos Líquidos/métodos , Anaerobiosis , Tamaño de la PartículaRESUMEN
The sequestration of CO2 and carbonation process for the stabilization of fresh fly ash from municipal solid waste (MSW) incinerator were investigated. The purpose of this paper is to evaluate the influence of fundamental parameters affecting the stabilization of heavy metal of Pb and diffusivity and reactivity of CO2 (i. e. the water content and concentration of CO2). In addition, the major physical and chemical changes in fly ash after carbonation were investigated using XRD and SEM. It shows that 10% or more water content added to fly ash could remarkably accelerate the sequestration of CO2, compared with control samples without water. The sequestration of CO2 is not remarkable within 1 day in the air atmosphere for low content of CO2 (0.03%). The XRD analysis indicates that CO2 could combine Ca(OH)2 to form CaCO3 and CO2 could also combine heavy metal oxides to form heavy metal carbonate (i.e. from PbO4 to PbCO3). Aggregates of crystals of sheet and cylinder can be observed by SEM.