| 1. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
|
|
| 2. |
- Liu, Zhiying, et al.
(författare)
-
Hysteresis-free thin-film transistors achieved by novel solution-processing of nanotubes/polymer composites
- 2012
-
Ingår i: Materials Research Society Spring Meeting 2012, San Francisco, April 9-13, 2012..
-
Konferensbidrag (refereegranskat)abstract
- Thin-film transistors (TFTs) based on single-walled carbon nanotubes (SWCNTs) have gained enormous attention in the community of flexible/stretchable electronics. At present, such TFTs often suffer from severe problems including giant hysteresis in their transfer characteristics. With SiO2 as the gate dielectric, extensive investigations have led to generally accepted understanding of the hysteresis as being caused by charge transfer between the SWCNTs and their surroundings including both water molecules bound on the SiO2 surface (Si≡OH) and the water/oxygen molecules in the ambient atmosphere. In order to combat the hysteresis issue, significant efforts have been made by annealing the TFTs in vacuum and separating SWCNTs from SiO2 by deposition of a self-assembled monolayer (SAM) on the SiO2 or passivating the SWCNTs with an organic or inorganic dielectric film. These methods, however, require either processing in inert environment or developing elaborated processes. In the present work, we demonstrate hysteresis-free TFTs based on SWCNT/polymer composite without any complex treatment. The composite consists of SWCNTs and poly-9,9_dioctyl-fluorene-co-bithiophene (F8T2). With the aid of polymer F8T2, SWCNTs can be efficiently dissolved in commonly used solvents thereby forming a uniform composite solution. By soaking a chip with predefined TFT structures on an oxidized Si substrate in the composite solution, direct assembly of the composite on the SiO2 occurs, leading to the formation of a composite thin film in the channel region of the TFTs. Although fabricated using a very simple process, our TFTs exhibit hysteresis-free operation under ambient conditions. It is plausible to suggest that SWCNTs are embedded in the F8T2 matrix with the latter providing an effective shield for the former against the trap sites on the SiO2 and the H2O/O2 molecules in the atmosphere. In comparison to the other reported means aiming at hysteresis reduction, the present method is simple, robust, solution processable, effective, and operable under ambient conditions. In addition, we have found F8T2 to preferentially disperse semiconducting SWCNTs rendering a selective removal of the metallic species in the solution. This selectivity is of paramount importance as it results in high-performance TFTs with both high on-state current (0.1 µA/µm @ channel length = 50 µm) and large on/off current ratio (103-105). The TFTs have also shown significantly improved uniformity and dimensional scalability with a mobility value of 10-20 cm2V-1s-1, which have allowed us to investigate the TFTs using the resultant logic circuits.
|
|
| 3. |
- Liu, Zhiying, et al.
(författare)
-
On Gate Capacitance of Nanotube Networks
- 2011
-
Ingår i: IEEE Electron Device Letters. - : IEEE. - 0741-3106 .- 1558-0563. ; 32:5, s. 641-643
-
Tidskriftsartikel (refereegranskat)abstract
- This letter presents a systematic investigation of the gate capacitance C-G of thin-film transistors (TFTs) based on randomly distributed single-walled carbon nanotubes (SWCNTs) in the channel. In order to reduce false counting of SWCNTs that do not contribute to current conduction, C-G is directly measured on the TFTs using a well-established method for MOSFETs. Frequency dispersion of C-G is observed, and it is found to depend on the percolation behavior in SWCNT networks. This dependence can be accounted for using an RC transmission line model. These results are of important implications for the determination of carrier mobility in nanoparticle-based TFTs.
|
|
| 4. |
- Li, Jiantong, et al.
(författare)
-
Contact-electrode insensitive rectifiers based on carbon nanotube network transistors
- 2008
-
Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 29:5, s. 500-502
-
Tidskriftsartikel (refereegranskat)abstract
- This letter presents rectifiers based on the diode connection of carbon nanotube network (CNN) transistors. Despite a low density of carbon nanotubes in the CNNs, the devices can achieve excellent performance with a forward/reverse current ratio reaching 10(5). By casting nanotube suspension on oxidized Si substrates with predefined electrodes, CNN-based field-effect transistors are readily prepared. By short-circuiting the source and gate terminals, CNN-based rectifiers are realized with the rectification characteristics independent of whether Pd or Al is employed as the contact electrodes. This independence is especially attractive for applications of CNN-based transistors/rectifiers in flexible electronics with various printing techniques.
|
|
| 5. |
|
|
| 6. |
- Liu, Zhiying, et al.
(författare)
-
Mobility Extraction for Nanotube TFTs
- 2011
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 32:7, s. 913-915
-
Tidskriftsartikel (refereegranskat)abstract
- An extensive investigation of carrier mobility is presented for thin-film transistors (TFTs) with single-walled carbon nanotube (SWCNT) networks as the semiconductor channel. For TFTs particularly with low-density SWCNTs in the networks, the extracted mobility using the standard method for Si metal-oxide-semiconductor field-effect transistors is erroneous, mainly resulting from use of a parallel-plate capacitor model and assumption of the source-drain current being inversely proportional to the channel length. Large hysteresis in the transfer characteristics further complicates the extraction. By properly addressing all these challenges in this letter, a comprehensive methodology is established, leading to the extraction of mobility values that are independent of geometrical parameters.
|
|
| 7. |
- Liu, Zhiying, et al.
(författare)
-
SMALL-Hysteresis Thin-Film Transistors Achieved by Facile Dip-Coating of Nanotube/Polymer Composite
- 2012
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 24:27, s. 3633-3638
-
Tidskriftsartikel (refereegranskat)abstract
- Small-hysteresis, high-performance thin-film transistors (TFTs) are readily realized simply by dip-coating of a solution-processable composite. The composite consists of single-walled carbon nanotubes (SWCNTs) embedded in semiconducting polymer used as the channel material. The resultant TFTs simultaneously exhibit large on/off current ratio, high on-current level, high mobility in the range 10−20 cm2V−1s−1, and good uniformity and scalability.
|
|
| 8. |
|
|
| 9. |
- Salvo, Gloria, et al.
(författare)
-
Open vs minimally invasive radical trachelectomy in early-stage cervical cancer : International Radical Trachelectomy Assessment Study
- 2022
-
Ingår i: American Journal of Obstetrics and Gynecology. - : Elsevier BV. - 0002-9378 .- 1097-6868. ; 226:1, s. 1-97
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Minimally invasive radical trachelectomy has emerged as an alternative to open radical hysterectomy for patients with early-stage cervical cancer desiring future fertility. Recent data suggest worse oncologic outcomes after minimally invasive radical hysterectomy than after open radical hysterectomy in stage I cervical cancer. Objective: We aimed to compare 4.5-year disease-free survival after open vs minimally invasive radical trachelectomy. Study Design: This was a collaborative, international retrospective study (International Radical Trachelectomy Assessment Study) of patients treated during 2005–2017 at 18 centers in 12 countries. Eligible patients had squamous carcinoma, adenocarcinoma, or adenosquamous carcinoma; had a preoperative tumor size of ≤2 cm; and underwent open or minimally invasive (robotic or laparoscopic) radical trachelectomy with nodal assessment (pelvic lymphadenectomy and/or sentinel lymph node biopsy). The exclusion criteria included neoadjuvant chemotherapy or preoperative pelvic radiotherapy, previous lymphadenectomy or pelvic retroperitoneal surgery, pregnancy, stage IA1 disease with lymphovascular space invasion, aborted trachelectomy (conversion to radical hysterectomy), or vaginal approach. Surgical approach, indication, and adjuvant therapy regimen were at the discretion of the treating institution. A total of 715 patients were entered into the study database. However, 69 patients were excluded, leaving 646 in the analysis. Endpoints were the 4.5-year disease-free survival rate (primary), 4.5-year overall survival rate (secondary), and recurrence rate (secondary). Kaplan-Meier methods were used to estimate disease-free survival and overall survival. A post hoc weighted analysis was performed, comparing the recurrence rates between surgical approaches, with open surgery being considered as standard and minimally invasive surgery as experimental. Results: Of 646 patients, 358 underwent open surgery, and 288 underwent minimally invasive surgery. The median (range) patient age was 32 (20–42) years for open surgery vs 31 (18–45) years for minimally invasive surgery (P=.11). Median (range) pathologic tumor size was 15 (0–31) mm for open surgery and 12 (0.8–40) mm for minimally invasive surgery (P=.33). The rates of pelvic nodal involvement were 5.3% (19 of 358 patients) for open surgery and 4.9% (14 of 288 patients) for minimally invasive surgery (P=.81). Median (range) follow-up time was 5.5 (0.20–16.70) years for open surgery and 3.1 years (0.02–11.10) years for minimally invasive surgery (P<.001). At 4.5 years, 17 of 358 patients (4.7%) with open surgery and 18 of 288 patients (6.2%) with minimally invasive surgery had recurrence (P=.40). The 4.5-year disease-free survival rates were 94.3% (95% confidence interval, 91.6–97.0) for open surgery and 91.5% (95% confidence interval, 87.6–95.6) for minimally invasive surgery (log-rank P=.37). Post hoc propensity score analysis of recurrence risk showed no difference between surgical approaches (P=.42). At 4.5 years, there were 6 disease-related deaths (open surgery, 3; minimally invasive surgery, 3) (log-rank P=.49). The 4.5-year overall survival rates were 99.2% (95% confidence interval, 97.6–99.7) for open surgery and 99.0% (95% confidence interval, 79.0–99.8) for minimally invasive surgery. Conclusion: The 4.5-year disease-free survival rates did not differ between open radical trachelectomy and minimally invasive radical trachelectomy. However, recurrence rates in each group were low. Ongoing prospective studies of conservative management of early-stage cervical cancer may help guide future management.
|
|
| 10. |
- Chen, Fei'er, et al.
(författare)
-
The effects of PM2.5 on asthmatic and allergic diseases or symptoms in preschool children of six Chinese cities, based on China, Children, Homes and Health (CCHH) project
- 2018
-
Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 232, s. 329-337
-
Tidskriftsartikel (refereegranskat)abstract
- The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1° × 0.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10 μg/m3 of the annual PM2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM2.5 exposure.
|
|
| 11. |
- Deng, Min, et al.
(författare)
-
Genome-wide association analyses in Han Chinese identify two new susceptibility loci for amyotrophic lateral sclerosis
- 2013
-
Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 45:6, s. 697-
-
Tidskriftsartikel (refereegranskat)abstract
- To identify susceptibility genes for amyotrophic lateral sclerosis (ALS), we conducted a genome-wide association study (GWAS) in 506 individuals with sporadic ALS and 1,859 controls of Han Chinese ancestry. Ninety top SNPs suggested by the current GWAS and 6 SNPs identified by previous GWAS were analyzed in an independent cohort of 706 individuals with ALS and 1,777 controls of Han Chinese ancestry. We discovered two new susceptibility loci for ALS at 1q32 (CAMK1G, rs6703183, P-combined = 2.92 x 10(-8), odds ratio (OR) = 1.31) and 22p11 (CABIN1 and SUSD2, rs8141797, P-combined = 2.35 x 10(-9), OR = 1.52). These two loci explain 12.48% of the overall variance in disease risk in the Han Chinese population. We found no association evidence for the previously reported loci in the Han Chinese population, suggesting genetic heterogeneity of disease susceptibility for ALS between ancestry groups. Our study identifies two new susceptibility loci and suggests new pathogenic mechanisms of ALS.
|
|
| 12. |
- Du, Jie, et al.
(författare)
-
Effects of rainfall intensity and slope on interception and precipitation partitioning by forest litter layer
- 2019
-
Ingår i: Catena. - : Elsevier BV. - 0341-8162. ; 172, s. 711-718
-
Tidskriftsartikel (refereegranskat)abstract
- Rainfall interception and other hydrologic processes affected by the forest litter layer are usually related to litter characteristics and rainfall conditions, with limited studies that consider the influence of slope. To simulate the hydrological functions of the litter layer at different slope gradients, artificial rainfall experiments were conducted at four rainfall intensities (from 30 to 120 mm hr−1) in horizontal and inclined trays (with the slope of 0° 10° 20° and 30°) with litter of Pinus tabuliformis or Quercus variabilis. The results indicated that (1) the dynamic process of litter interception had 3 phases: a rapid intercepted phase within the first 5 min, a moderate intercepted phase and a post-rainfall drainage phase; (2) the maximum interception storage (Cmax) and the minimum interception storage (Cmin) of Q. variabilis were larger than those of P. tabuliformis; (3) Cmax and Cmin were correlated with slope for both types of litter, whereas only Cmax was correlated with rainfall intensity; and (4) lateral flow amount significantly increased with both slope gradient and rainfall intensity only for Quercus variabilis, whereas drainage volume showed significant correlation with rainfall intensity. Moreover, the ratio of lateral runoff and drainage was affected by slope gradient whereas percentage of litter interception had a good relationship with rainfall intensity, rather than slope, with litter interception and drainage contributing the smallest and the largest proportions, respectively. Overall, the results demonstrate the effect of rainfall and slope factors on hydrological processes in the forest litter layer.
|
|
| 13. |
- Guo, Jianqiu, et al.
(författare)
-
Maternal and childhood urinary phenol concentrations, neonatal thyroid function, and behavioral problems at 10 years of age : The SMBCS study
- 2020
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 743
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Environmental phenols, bisphenol A (BPA), triclosan (TCS), and benzophenone-3 (BP-3), are known as emerging endocrine-disrupting chemicals; however, their impacts on thyroid hormones and children's neurobehaviors are still unclear.OBJECTIVES: We aimed to examine the associations of prenatal and childhood exposure to phenols with neonatal thyroid function and childhood behavioral problems aged 10 years.METHODS: A total of 386 mother-singleton pairs were included from Sheyang Mini Birth Cohort Study (SMBCS), a longitudinal birth cohort in China. We quantified urinary BPA, TCS and BP-3 concentrations in maternal and 10-year-old children's urine samples using gas chromatography tandem mass spectrometry and thyroid function parameters in cord serum samples. Caregivers completed the Strength and Difficulties Questionnaire (SDQ) for their children at 10 years of age. Multivariable linear regression models and logistic regression models were applied to estimate associations of urinary phenol concentrations with thyroid hormones and risks of children's behavioral problems, respectively.RESULTS: The median values of urinary BPA, TCS and BP-3 concentrations for pregnant women were 1.75 μg/L, 0.54 μg/L and 0.37 μg/L, while 1.29 μg/L, 6.64 μg/L and 1.39 μg/L for children, respectively. Maternal urinary BPA concentrations were in associations with 1.00% [95% confidence interval (CI): 0.20%, 1.92%] increases in cord serum FT4 concentrations and significantly associated with increased risks of total difficulties [odds ratio (OR): 1.45, 95% CI: 1.07, 1.97], while maternal urinary levels of BP-3 were significantly related to poorer prosocial behaviors (OR: 1.58, 95% CI: 1.04, 2.39) of children at 10 years of age. In sex-stratified analyses, maternal urinary BPA concentrations were related to increased total difficulty subscales only in boys.CONCLUSIONS: The findings indicated that higher prenatal urinary BPA concentrations were associated with increased risks of total difficulties, especially in boys and maternal urinary BP-3 concentrations were related to poorer prosocial behaviors at 10 years.
|
|
| 14. |
- Guo, Jianqiu, et al.
(författare)
-
Prenatal exposure to multiple phenolic compounds, fetal reproductive hormones, and the second to fourth digit ratio of children aged 10 years in a prospective birth cohort
- 2021
-
Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 263
-
Tidskriftsartikel (refereegranskat)abstract
- Select phenols are known to possess hormone-disrupting properties, but no previous study has addressed the potential effects of prenatal exposure to phenol mixtures on fetal reproductive hormones and children's second to fourth digit (2D: 4D) ratio, a marker for in utero testosterone (T) exposure. We aimed to explore interrelations of prenatal phenol exposures individually and in mixtures, cord serum reproductive hormones, and 2D: 4D ratio of children aged 10 years. Urinary 11 phenol concentrations were determined from 392 pregnant women participating in a longitudinal birth cohort. We estimated associations of prenatal phenol exposures individually and in mixtures with cord reproductive hormones and children's 2D:4D ratio using three statistical approaches, including generalized linear models (GLMs), elastic net regression (ENR) models and Bayesian kernel machine regression (BKMR) models. In female newborns, the three models showed that maternal triclosan (TCS) concentrations were significantly negatively associated with cord serum T levels [regression coefficient (β) = -0.076, 95% confidence interval (CI): 0.138, -0.013; p = 0.018]. Additionally, maternal urinary bisphenol A (BPA) levels were related to decreases in 2D:4D ratio of the left hand in girls by GLMs (β = -0.003, 95% CI: 0.007, -0.001; p = 0.024) and ENR models, but not BKMR models. We provided evidence that prenatal TCS exposure predicted lower cord serum T levels, and maternal BPA exposure was related to decreased 2D:4D ratio of the left hand in females.
|
|
| 15. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
-
Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
-
Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
|
|
| 16. |
- Li, Wenting, et al.
(författare)
-
Effects of prenatal exposure to five parabens on neonatal thyroid function and birth weight : Evidence from SMBCS study
- 2020
-
Ingår i: Environmental Research. - : Academic Press. - 0013-9351 .- 1096-0953. ; 188
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Parabens, suspected as endocrine-disrupting chemicals, are nearly ubiquitous in the human body and exposure to these chemicals during pregnancy may disrupt thyroid hormones homeostasis and even affect fetal growth, although the impacts are still unclear.OBJECTIVES: We aimed to estimate associations of maternal urinary paraben concentrations with cord serum thyroid hormones and birth weight.METHODS: A subset of 437 mother-newborn pairs were included from a prospective birth cohort with five parabens quantified in maternal urine and seven thyroid function indicators measured in cord serum samples. Multivariable linear regression models and elastic net regression (ENR) models were applied to explore associations between individual and mixtures of prenatal urinary paraben concentrations and thyroid hormones and birth weight, respectively.RESULTS: Maternal urinary ethyl-paraben (EtP) concentrations were associated with increased cord serum total triiodothyronine levels (TT3) [percent change: 1.51%; 95% confidence interval (CI): 0.20%, 2.74%; p=0.017]. Urinary propyl-paraben (PrP) levels predicted higher thyroid peroxidase antibodies (percent change: 4.19%, 95% CI: 0.20%, 8.44%; p=0.041). Maternal urinary EtP and butyl-paraben (BuP) concentrations were significantly positively associated with birth weight [regression coefficient, (β)=40.9g, 95% CI: 3.99, 76.6; p=0.030; β=62.1g, 95% CI: 8.70, 115; p=0.023, for EtP and BuP, respectively]. In sex-stratified analyses, positive relationship between EtP levels and birth weight was observed in boys. Urinary EtP concentrations predicted higher TT3 levels in cord serum samples, assessing parabens as a chemical mixture with ENR models.CONCLUSIONS: Prenatal exposure to parabens may affect thyroid hormone indicators with increased serum TT3 levels and associate with higher birth weight, especially in boys. The underlying biological mechanisms and effects of prenatal paraben exposures on disruption of thyroid function homeostasis and potential impacts of childhood growth and development needed to be further investigated.
|
|
| 17. |
- Li, Yongqiang, 1992, et al.
(författare)
-
Assessment of compositional changes of carbonated cement pastes subjected to high temperatures using in-situ Raman mapping and XPS
- 2022
-
Ingår i: Journal of Building Engineering. - : Elsevier BV. - 2352-7102. ; 45
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new method for assessing the compositional changes of carbonated cement pastes subjected to high temperatures. In this new method, in-situ Raman mapping combined with X-ray photoelectron spectroscopy (XPS) was used to monitor the phase transformation in carbonated cement pastes subjected to various high temperatures from 30 to 950 degrees C. Two kinds of carbonated areas, i.e., vaterite dominated and calcite dominated, were found in the in-situ Raman measurements. With the elevation in temperature, most of the vaterite was converted to calcite at 500 degrees C and completely decomposed at 600 degrees C, while the decomposition of calcite started at 600 degrees C and finished at 720 degrees C. Meanwhile, the depolymerization of the calcium modified silica gel to the silicate phases with a lower degree of polymerization was initiated at 500 degrees C, which led to the crystallization of beta-C2S at 600 degrees C. The generation of beta-C2S was found to increase with the elevation in temperature and became the dominant phase at 950 degrees C. In conclusion, the high temperature could affect the stability of carbonated cement pastes at 500 degrees C and above. The in-situ Raman mapping measurement has provided an extraordinary view of the spatial distribution of interesting phases subjected to high temperatures in a nondestructive way, which should be more consistent with the true condition in the material.
|
|
| 18. |
- Li, Yongqiang, et al.
(författare)
-
Chemical and mineralogical characteristics of carbonated and uncarbonated cement pastes subjected to high temperatures
- 2021
-
Ingår i: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368. ; 216
-
Tidskriftsartikel (refereegranskat)abstract
- The fire-resistance of carbonated concrete under high temperatures is significant due to its direct exposure during an accidental fire. To evaluate the carbonation effect on fire-resistance of concrete, the chemical and mineralogical changes of uncarbonated and carbonated cement pastes subjected to high temperatures were thoroughly investigated in this research by employing micro-measurement methods including thermal-gravimetric analysis (TGA), X-ray diffraction (XRD) and Si nuclear magnetic resonance ( Si NMR). Uncarbonated cement paste results showed the decomposition of portlandite at 400 °C with the formation of lime, whilst the depolymerization of C–S–H happened simultaneously to generate monomeric silicon tetrahedron. Above 720 °C, all the C–S–H depolymerized to crystalline C S. Carbonated cement pastes on the other hand showed that amorphous calcium carbonate and part of vaterite decomposed between the range of 400–600 °C, while the rest of the vaterite and calcite were decomposed at 600–720 °C. The individual content of calcium carbonate polymorph could not be obtained using a TGA curve. Besides, the calcium-modified silicate gel was significantly decomposed at 500 °C and completely depolymerized to crystalline C S at 950 °C. In summary, carbonated pastes show better resistance to high temperatures with its heat absorption capacity 3.3 times as high as the uncarbonated sample, which delays the temperature development in the inner layer. Therefore, a reasonable carbonation process could help to improve the fire resistance of concrete to some extent.
|
|
| 19. |
- Li, Yong Qiang, et al.
(författare)
-
Carbonation of the synthetic calcium silicate hydrate (C-S-H) under different concentrations of CO2: Chemical phases analysis and kinetics
- 2020
-
Ingår i: Journal of CO2 Utilization. - : Elsevier BV. - 2212-9820. ; 35, s. 303-313
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the chemical phases analysis and the kinetics of synthetic calcium silicate hydrate (C-S-H) under differentCO2concentrations (natural (0.03%), 3%, 10%, 20%, 50%, 100%) were investigated. For this aim, the scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed for microstructure characterisation. The 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) coupled with mass spectrometer (MS) were used for characterising the chemical phases before and after carbonation. From the NMR results, it was found that C-S-H would be partly decalcified under the natural condition but completely under the accelerated conditions. Two equations related to the carbonation kinetics under natural and accelerated conditions were proposed respectively. The compositions in decalcified C-S-H were not affected by the CO2 concentration. The XRD analysis showed that vaterite, aragonite and calcite were coexistent after carbonation, which would be transformed to aragonite and calcite with further carbonation. The preferential formation of the allotropic calcium carbonate was not impacted by the concentration of CO2 either. Based on the TGA-MS test, the stoichiometric formula of synthetic C-S-H was determined with CaOâ'™SiO2â'™0.87H2O or Câ Sâ H0.87. In addition, a carbonation kinetics model was proposed to learn the carbonation kinetics of C-S-H carbonated in different CO2 concentrations. The experimental data fitted well with the model. The carbonation kinetics between 3% and 20% CO2 are similar, but different from that under 50% and 100% CO2
|
|
| 20. |
- Li, Zhijun, et al.
(författare)
-
An Optimization Study of Manufacturing Variation Effects on Diesel Injector Design with Emphasis on Emissions
- 2005
-
Ingår i: S A E Transactions. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0096-736X. ; 113:Section 5, s. 724-733
-
Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the effects of manufacturing variations in fuel injectors on the engine performance with emphasis on emissions. The variations are taken into consideration within a Reliability-Based Design Optimization (RBDO) framework. A reduced version of Multi-Zone Diesel engine Simulation (MZDS), MZDS-lite, is used to enable the optimization study. The numerical noise of MZDS-lite prohibits the use of gradient-based optimization methods. Therefore, surrogate models are developed to filter out the noise and to reduce computational cost. Three multi-objective optimization problems are formulated, solved and compared: deterministic optimization using MZDS-lite, deterministic optimization using surrogate models and RBDO using surrogate models. The obtained results confirm that manufacturing variation effects must be taken into account in the early product development stages
|
|
| 21. |
|
|
| 22. |
- Li, Zhijun, et al.
(författare)
-
Multiobjective optimization for integrated tolerance allocation and fixture layout design in multistation assembly
- 2006
-
Ingår i: Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - 20. - New York : American Society of Mechanical Engineers. ; , s. 199-206
-
Konferensbidrag (refereegranskat)abstract
- Cost and product quality are significant attributes in manufacturing processes, such as multistation assembly. We use multiobjective optimization for integrated tolerance allocation and fixture layout design to address their interaction and to quantify tradeoffs among cost, product quality, and assembly process robustness. Design decisions relate to product tolerances, assembly process tolerances, and fixture locating positions. A nested optimization strategy is adopted, and the proposed methodology is demonstrated using a vehicle side frame assembly example. The obtained results provide evidence for the existence of tradeoffs, based on which we can identify critical quality and budget requirements.
|
|
| 23. |
- Li, Zhijun, et al.
(författare)
-
Multiobjective Optimization for Integrated Tolerance Allocation and Fixture Layout Design in Multistation Assembly
- 2008
-
Ingår i: Journal of manufacturing science and engineering. - : ASME International. - 1087-1357 .- 1528-8935. ; 130:4, s. 0445011-0445016
-
Tidskriftsartikel (refereegranskat)abstract
- Cost and dimensional variation of products are significant attributes in multistation assembly processes. These attributes depend on product/process tolerances and fixture layouts. Typically, tolerance allocation and fixture layout design are conducted separately without considering potential interrelations. In this work, we use multiobjective optimization for integrated tolerance allocation and fixture layout design to address interactions and to quantify tradeoffs among cost, product variation, and assembly process sensitivity. A nested optimization strategy is applied to a vehicle side frame assembly. Results demonstrate the presence and quantification of tradeoffs, based on which we introduce the concept of critical variation and critical budget requirements
|
|
| 24. |
- Li, Zhijun, et al.
(författare)
-
Product and Process Tolerance Allocation in Compliant Multistation Assembly Using Analytical Target Cascading
- 2008
-
Ingår i: Journal of mechanical design (1990). - : ASME International. - 1050-0472 .- 1528-9001. ; 130:9
-
Tidskriftsartikel (refereegranskat)abstract
- Tolerance allocation is the process of determining allowable dimensional variations in products (parts and subassemblies) and processes (fixtures and tools) in order to meet final assembly quality and cost targets. Traditionally, tolerance allocation is conducted by solving a single optimization problem. This "all-in-one" (AIO) approach may not be desirable or applicable for various reasons: the assembler of the final product may not have access to models and∕or data to compute appropriate tolerance values for all subassemblies and parts in the case of outsourcing; optimization algorithms may face numerical difficulties when solving very large-scale, simulation-based nonlinear problems; interactions are often obscured in AIO models and trade-offs may not be quantifiable readily. This paper models multistation compliant assembly as a hierarchical multilevel process and proposes the application of analytical target cascading for formulating and solving the tolerance allocation problem. Final product quality and cost targets are translated into tolerance specifications for incoming parts, subassemblies, and station fixtures. The proposed methodology is demonstrated using a vehicle side frame assembly example. Both quality- and cost-driven tolerance allocation problems are formulated. A parametric study with respect to budget is conducted to quantify the cost-quality trade-off. We believe that the proposed multilevel optimization methodology constitutes a valuable new paradigm for tolerance design in multistation assembly involving a large number of parts and stations, and creates research opportunities in this area.
|
|
| 25. |
- Li, Zhijun, et al.
(författare)
-
Product tolerance allocation in compliant multistation assembly through variation propagation and analytical target cascading
- 2004
-
Ingår i: Proceedings of the ASME Design Engineering Division - 2004. - New York : American Society of Mechanical Engineers. - 0791847055 ; , s. 813-820
-
Konferensbidrag (refereegranskat)abstract
- Compliant sheet metal assembly is a hierarchical manufacturing process that plays a significant role in automotive product development. Parts are joined in different stations to form the final product (e.g., the vehicle body structure). Dimensional variation is a product attribute of major importance that characterizes quality, and is mainly affected by the variability of parts, fixtures, and joining methods at each of the multiple stations. The propagation of dimensional variation through the multistation assembly system is modeled as a linear process, where all three aforementioned sources of variability are taken into account at each station using finite element models. In this article we apply the analytical target cascading process to the tolerance allocation problem in multistation assembly systems. Specifically, we translate final product variation targets to tolerance specifications for subassemblies and incoming parts. We demonstrate the methodology by means of a vehicle side frame assembly example.
|
|
| 26. |
- Liu, W., et al.
(författare)
-
Changes in chemical phases and microscopic characteristics of fly ash blended cement pastes in different CO 2 concentrations
- 2020
-
Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 257
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of CO2 concentration on changes in chemical phases and microscopic characteristics for fly ash (FA) blended cement pastes were investigated in this study. Several microscopic test methods, including X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), 29Si nuclear magnetic resonance (29Si NMR) and scanning electron microscope (SEM), were used to characterize the chemical compositions and microscopic features. The XRD results showed that the precipitation of allotropic calcium carbonate (CC̅) includes calcite (c), aragonite (a) and vaterite (v). The ratio of c/(a + v) was around 0.6 under 3% and 20% CO2, while more percentage of calcite was generated under 100% CO2 (c/(a + v) = 0.79). The precipitation of more calcite than vaterite and aragonite happened with the CO2 concentration elevated to 100%. TGA analysis indicated that the total content of CC̅ was similar under all accelerated conditions and higher than that under natural carbonation. Additionally, in the 29Si NMR spectra, more C-S-H (about 70%) was decalcified after accelerated carbonation compared with natural carbonation (54.1%). The decalcification degree was the same for 3% and 20% CO2 and showed the highest value under 100% CO2. The microstructure changes characterized by SEM observation exhibited denser microstructure after carbonation with the formation of CC̅ but no apparent difference was observed with different CO2 concentrations based on the SEM pictures. Compared with the carbonation of ordinary Portland cement (OPC) paste, the carbonation of FA blended cement paste was more inclined to precipitate as calcite than vaterite and aragonite and caused a lower decalcification degree of C-S-H. Overall, similar to OPC paste, the carbonation results obtained in natural and accelerated conditions for FA blended cement pastes were different and the conditions between 3% and 20% CO2 were similar while 100% CO2 showed different results.
|
|
| 27. |
- Liu, Wei, et al.
(författare)
-
Slag Blended Cement Paste Carbonation under Different CO(2)Concentrations: Controls on Mineralogy and Morphology of Products
- 2020
-
Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:15, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the effect of different CO(2)concentrations on the carbonation results of slag blended cement pastes, carbonation experiments under natural (0.03% CO2) and accelerated conditions (3, 20, and 100% CO2) were investigated with various microscopic testing methods, including X-ray diffraction (XRD),Si-29 magic angle spinning nuclear magnetic resonance (Si-29 MAS NMR) and scanning electron microscopy (SEM). The XRD results indicated that the major polymorphs of CaCO(3)after carbonation were calcite and vaterite. The values of the calcite/(aragonite + vaterite) (c/(a + v)) ratios were almost the same in all carbonation conditions. Additionally, NMR results showed that the decalcification degree of C-S-H gel exposed to 0.03% CO(2)was less than that exposed to accelerated carbonation; under accelerated conditions, it increased from 83.1 to 84.2% when the CO(2)concentration improved from 3% to 100%. In SEM observations, the microstructures after accelerated carbonation were denser than those under natural carbonation but showed minor differences between different CO(2)concentrations. In conclusion, for cement pastes blended with 20% slag, a higher CO(2)concentration (above 3%) led to products different from those produced under natural carbonation. A further increase in CO(2)concentration showed limited variation in generated carbonation products.
|
|
| 28. |
- Liu, Zhiying, 1982-, et al.
(författare)
-
Solution-Processed Logic Gates Based On Nanotube/Polymer Composite
- 2013
-
Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 60:8, s. 2542-2547
-
Tidskriftsartikel (refereegranskat)abstract
- Hysteresis-free logic gates capable of operation at 100 kHz are fabricated basing on local-gate thin-film transistors with their channel featuring solution-processed composite films of single-walled carbon nanotubes (SWCNTs) and poly(9,9-dioctylfluorene-co-bithiophene) (F8T2). Using dip-coating for deposition of composite films, high-density SWCNTs are found to be embedded in an F8T2 layer and thus being kept from the underlying AlOx gate dielectric by a certain distance. The presence of the F8T2 interlayer effectively suppresses hysteresis although it also weakens the gate electrostatic control. The fabricated transistors are characterized by nil hysteresis, high carrier mobility, large ON/OFF current ratio, low operation voltage, small subthreshold swing, and remarkable scalability. These properties are crucial for the realization of the well-performing logic circuits.
|
|
| 29. |
- Luo, Jun, et al.
(författare)
-
On Different Process Schemes for MOSFETs With a Controllable NiSi-Based Metallic Source/Drain
- 2011
-
Ingår i: IEEE Transactions on Electron Devices. - : IEEE Institute of Electrical and Electronics. - 0018-9383 .- 1557-9646. ; 58:7, s. 1898-1906
-
Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on different silicidation schemes toward a controllable NiSi-based metallic source/drain (MSD) process with restricted lateral encroachment of NiSi. These schemes include thickness control of Ni, Ni-Pt alloying, and two-step annealing. Experimental results show that all the three process schemes can give rise to effective control of lateral encroachment during Ni silicidation. By controlling t(Ni), NiSi-based MSD metal-oxide-semiconductor field-effect transistors (MOSFETs) of gate length L-G = 55 nm are readily realized on ultrathin-body silicon-on-insulator substrates with 20-nm surface Si thickness. With the aid of dopant segregation (DS) to modifying the Schottky barrier heights of NiSi, both n- and p-type MSD MOSFETs show significant performance improvement, compared to reference devices without DS.
|
|
| 30. |
- Luo, Jun, et al.
(författare)
-
Surface-energy triggered phase formation and epitaxy in nanometer-thick Ni1-xPtx silicide films
- 2010
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 96:3
-
Tidskriftsartikel (refereegranskat)abstract
- The formation of ultrathin silicide films of Ni1-xPtx at 450-850 degrees C is reported. Without Pt (x=0) and for t(Ni)< 4 nm, epitaxially aligned NiSi2-y films readily grow and exhibit extraordinary morphological stability up to 800 degrees C. For t(Ni)>= 4 nm, polycrystalline NiSi films form and agglomerate at lower temperatures for thinner films. Without Ni (x=1) and for t(Pt)=1-20 nm, the annealing behavior of the resulting PtSi films follows that for the NiSi films. The results for Ni1-xPtx of other compositions support the above observations. Surface energy is discussed as the cause responsible for the distinct behavior in phase formation and morphological stability.
|
|
| 31. |
- Luo, Ziteng, et al.
(författare)
-
Roots-Enhanced Preferential Flows in Deciduous and Coniferous Forest Soils Revealed by Dual-Tracer Experiments
- 2019
-
Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425. ; 48:1, s. 136-146
-
Tidskriftsartikel (refereegranskat)abstract
- Macropores formed by roots are crucial channels for preferential flows in forest soils that are largely responsible for water percolation and solute leaching. Using dual-tracer experiments (Brilliant Blue FCF and bromide [Br]), this study investigated the preferential flows of water and solutes in a deciduous forest dominated by Bl. and a coniferous forest mainly planted with (L.) Franco. Dye-stained patterns and concentrations of Brilliant Blue and Br were obtained in vertical soil profiles (0-30 cm), whereas stained and unstained roots were collected and analyzed in horizontal soil profiles to a 30-cm soil depth. Brilliant Blue and Br were mainly accumulated in the 0- to 20-cm soil depth, which had greater total root length density than the 20- to 30-cm soil depth ( < 0.05). Only part of the roots facilitated the preferential flows, with finer roots (i.e., diameter <1 mm) contributing the most. More intriguingly, the coniferous forest soil had a greater degree of preferential flows and greater tracer concentrations at deeper soil depth than the deciduous forest soil, suggesting the importance of tree species and forest composition on water and solute transport in forest ecosystems.
|
|
| 32. |
|
|
| 33. |
- Ning, Zhijun, et al.
(författare)
-
Role of surface ligands in optical properties of colloidal CdSe/CdS quantum dots.
- 2011
-
Ingår i: Physical chemistry chemical physics : PCCP. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 13:13, s. 5848-54
-
Tidskriftsartikel (refereegranskat)abstract
- In order to study the role of surface ligands in determining optical properties of colloidal quantum dots (QDs), we have selectively fabricated and studied CdSe/CdS core-shell QDs with strongly confined electron and hole states attached with commonly used surface ligands. Optical properties, viz. absorption and fluorescence of these QDs, are characterized from which salient changes have been observed for different ligand substitutions which, through theoretical analysis, can be associated with electronic structure properties of the QD-ligand composite systems, in particular localization of wave functions of electrons and holes in the QDs and the band matching of the HOMO-LUMO gap of the ligands. The findings can be utilized to facilitate the understanding and optimization of properties of QD biomarkers with functionalizing surface ligands for targeting cellular objects.
|
|
| 34. |
- Ning, Zhijun, et al.
(författare)
-
Type-II colloidal quantum dot sensitized solar cells with a thiourea based organic redox couple.
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:13, s. 6032-6037
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, one kind of org. electrolyte based on tetramethylthiourea is employed for quantum dot sensitized solar cells (QDSCs). By reducing the impedance between the electrolyte and the counter electrode, the fill factor of such org. electrolyte based QDSCs is significantly improved. It is possible to substantially increase the photovoltage and to reach an efficiency three times higher than that of a commonly used inorg. electrolyte. The light harvesting ability of the org. electrolyte based QDSCs is successfully extended by using type-II QDs, where the adsorption of ZnS gives an addnl. advantage in further enhancing the stability of the cells. It is obsd. that core/shell ZnSe/CdS type-II QDs give higher electron injection than CdS/ZnSe QDs, proving that the electron distribution in the QDs is important for the electron extn. A full working mechanism of the org. redox couple for the QDSCs is proposed. [on SciFinder(R)]
|
|
| 35. |
- Qiu, Zhijun, et al.
(författare)
-
A comparative study of two different schemes to dopant segregation at NiSi/Si and PtSi/Si interfaces for Schottky barrier height lowering
- 2008
-
Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 55:1, s. 396-403
-
Tidskriftsartikel (refereegranskat)abstract
- An experimental study is presented to compare two different schemes used to incorporate a high concentration of dopants at the silicide/silicon interface for NiSi and PtSi, i.e., dopant segregation, with the purpose of lowering the Schottky barrier height (SBH) of the contact systems. Specifically, the interfacial dopant is introduced either through silicidation-induced dopant segregation (SIDS) or by silicide as diffusion source (SADS). For the latter, a postimplantation drive-in anneal is needed. For both silicide systems, the dopant segregation gives rise to a predominant effect, leading to an effective SBH that is independent of the original SBHs of PtSi and NiSi, which differs by 0.2 eV. Scheme SUDS is relatively simple in processing, but the silicidation process is dopant-dependent, leading to local variations of silicide formation. Scheme SADS addresses the adverse effect of dopant on silicidation by separating silicidation from dopant incorporation.
|
|
| 36. |
- Qu, Minni, et al.
(författare)
-
Interaction of bipolaron with the H2O/O-2 redox couple causes current hysteresis in organic thin-film transistors
- 2014
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5, s. 3185-
-
Tidskriftsartikel (refereegranskat)abstract
- Hysteresis in the current–voltage characteristics is one of the major obstacles to the implementation of organic thin-film transistors in large-area integrated circuits. The hysteresis has been correlated either extrinsically to various charge-trapping/transfer mechanisms arising from gate dielectrics or surrounding ambience or intrinsically to the polaron–bipolaron reaction in low-mobility conjugated polymer thin-film transistors. However, a comprehensive understanding essential for developing viable solutions to eliminate hysteresis is yet to be established. By embedding carbon nanotubes in the polymer-based conduction channel of various lengths, here we show that the bipolaron formation/recombination combined with the H2O/O2 electrochemical reaction is responsible for the hysteresis in organic thin-film transistors. The bipolaron-induced hysteresis is a thermally activated process with an apparent activation energy of 0.29 eV for the bipolaron dissociation. This finding leads to a hysteresis model that is generally valid for thin-film transistors with both band transport and hopping conduction in semiconducting thin films.
|
|
| 37. |
- Tian, Shangjie, et al.
(författare)
-
Magnetic topological insulator MnBi6 Te10 with a zero-field ferromagnetic state and gapped Dirac surface states
- 2020
-
Ingår i: Physical Review B. - 2469-9950. ; 102:3
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic topological insulators (TIs) with nontrivial topological electronic structure and broken time-reversal symmetry exhibit various exotic topological quantum phenomena. The realization of such exotic phenomena at high temperature is one of the central topics in this area. We reveal that MnBi6Te10 is a magnetic TI with an antiferromagnetic ground state below 10.8 K whose nontrivial topology is manifested by Dirac-like surface states. The ferromagnetic axion insulator state with Z4=2 emerges once spins are polarized at a field as low as 0.1 T, accompanied with saturated anomalous Hall resistivity up to 10 K. Such a ferromagnetic state is preserved even with an external field down to zero at 2 K. Theoretical calculations indicate that the few-layer ferromagnetic MnBi6Te10 is also topologically nontrivial with a nonzero Chern number. Angle-resolved photoemission spectroscopy experiments further reveal three types of Dirac surface states arising from different terminations on the cleavage surfaces, one of which has insulating behavior with an energy gap of ∼28 meV at the Dirac point. These outstanding features suggest that MnBi6Te10 is a promising system to realize various topological quantum effects at zero field and high temperature.
|
|
| 38. |
- Wang, Bing, et al.
(författare)
-
Efficient organic mulch thickness for soil and water conservation in urban areas
- 2021
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- The use of organic mulch is important for urban green applications. For urban areas in arid and semiarid regions receiving short high-intensive rainfall, rainfall characteristics, and soil slope play an important role for mulch functioning. These properties of mulch were studied. For this purpose, rainfall simulation experiments using organic mulching were conducted in Jiufeng National Forestry Park to analyze the influence of organic mulch under different slope and heavy rainfall events. The results showed that soil water content displayed a decreasing tendency with increasing mulch application. Compared to bare soil, a mulch application of 0.25 kg/m2 and 0.50 kg/m2 led to maximum soil water content and maximum runoff decrease occurred for 0.50 kg/m2 mulch. Higher application rate of mulch displayed less soil water content and greater runoff. The runoff amount and runoff generation rate decreased by 28–83% and 21–83%, respectively, as compared to bare soil. With a mulch application of 0.25–1.00 kg/m2, soil drainage accounted for 56–60% of total rainfall. Overall, an efficient mulch application was found to be 0.25–0.50 kg/m2. The results of this study are relevant for arid and semiarid urban regions that experience heavy rainfall.
|
|
| 39. |
- Wang, Hui, et al.
(författare)
-
A novel Schiff base derivative: Synthesis, two-photon absorption properties and application for bioimaging
- 2018
-
Ingår i: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1386-1425 .- 1873-3557. ; 198, s. 304-308
-
Tidskriftsartikel (refereegranskat)abstract
- A novel donor-pi-acceptor-pi-donor type (D-pi-A-pi-D) Schiff base derivative (L) has been designed and synthesized. The structure of L is confirmed by single-crystal X-ray diffraction analysis as well. The photophysical properties of compound L were comprehensively investigated by using both experimental and theoretical methods. The results indicate that L exhibits large Stokes shift and moderate two-photon action (2PA) cross-section in the near infrared (NIR) region. Furthermore, the confocal microscopy imaging study demonstrates that compound L could penetrate into cells and target the cellular mitochondria compartment. Due to its low cytotoxicity, compound L provides a promising tool for directly lighting up the mitochondria compartment in living HepG2 cells. (C) 2018 Elsevier B.V. All rights reserved.
|
|
| 40. |
- Wang, Hao, et al.
(författare)
-
In-situ growth of low-dimensional perovskite-based insular nanocrystals for highly efficient light emitting diodes
- 2023
-
Ingår i: Light. - : SPRINGERNATURE. - 2095-5545 .- 2047-7538. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Regulation of perovskite growth plays a critical role in the development of high-performance optoelectronic devices. However, judicious control of the grain growth for perovskite light emitting diodes is elusive due to its multiple requirements in terms of morphology, composition, and defect. Herein, we demonstrate a supramolecular dynamic coordination strategy to regulate perovskite crystallization. The combined use of crown ether and sodium trifluoroacetate can coordinate with A site and B site cations in ABX(3) perovskite, respectively. The formation of supramolecular structure retard perovskite nucleation, while the transformation of supramolecular intermediate structure enables the release of components for slow perovskite growth. This judicious control enables a segmented growth, inducing the growth of insular nanocrystal consist of low-dimensional structure. Light emitting diode based on this perovskite film eventually brings a peak external quantum efficiency up to 23.9%, ranking among the highest efficiency achieved. The homogeneous nano-island structure also enables high-efficiency large area (1 cm(2)) device up to 21.6%, and a record high value of 13.6% for highly semi-transparent ones.
|
|
| 41. |
- Xia, Haisheng, et al.
(författare)
-
Shaping high-performance wearable robots for human motor and sensory reconstruction and enhancement
- 2024
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- Most wearable robots such as exoskeletons and prostheses can operate with dexterity, while wearers do not perceive them as part of their bodies. In this perspective, we contend that integrating environmental, physiological, and physical information through multi-modal fusion, incorporating human-in-the-loop control, utilizing neuromuscular interface, employing flexible electronics, and acquiring and processing human-robot information with biomechatronic chips, should all be leveraged towards building the next generation of wearable robots. These technologies could improve the embodiment of wearable robots. With optimizations in mechanical structure and clinical training, the next generation of wearable robots should better facilitate human motor and sensory reconstruction and enhancement.
|
|
| 42. |
- Xu, Feng, et al.
(författare)
-
Fractional Exhaled Nitric Oxide in Relation to Asthma, Allergic Rhinitis, and Atopic Dermatitis in Chinese Children
- 2011
-
Ingår i: Journal of Asthma. - : Informa UK Limited. - 0277-0903 .- 1532-4303. ; 48:10, s. 1001-1006
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of airway inflammation. Our aim was to analyze the interrelationship and differentiate the predicting effects of asthma, allergic rhinitis (AR), and atopic dermatitis (AD) on the FeNO levels in children from mainland China. METHODS: A case-control study with age- and gender matched 1:1 was designed based on a larger cross-sectional survey on asthma, AR, and AD in Shanghai. A self-administered questionnaire was used to collect information on children's health information. Children with positive reports on physician-diagnosed asthma and/or AR and/or AD were recruited as cases, and children with no report of any of the diseases were designated as controls. The FeNO measurement was performed online, using the NIOX MINO® instrument (Aerocrine AB, Solna, Sweden) at 50 ml/min. RESULTS: A total of 130 subjects (65 cases and 65 controls, average age = 10 years) were recruited in this study. The average FeNO level was significantly higher in the cases (29.8 ± 1.9 ppb) than that in the controls (13.3 ± 1.7 ppb) (p < .001). Using multiple linear regression analysis controlling for confounding factors, including parental asthma/allergic diseases and home exposure, asthma (β = 0.330, p < .001) and AR (β = 0.157, p = .006) showed significant predicting effects for high FeNO levels, whereas AD was not related to the FeNO levels. CONCLUSIONS: Both asthma and AR could independently increase the FeNO levels in Chinese schoolchildren. Other diseases besides asthma should be considered when applying FeNO as a screening tool for asthma in Chinese children.
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
- Yuan, Chunze, et al.
(författare)
-
Improving the Photocurrent in Quantum-Dot-Sensitized Solar Cells by Employing Alloy PbxCd1-xS Quantum Dots as Photosensitizers
- 2016
-
Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 6:6
-
Tidskriftsartikel (refereegranskat)abstract
- Ternary alloy PbxCd1-xS quantum dots (QDs) were explored as photosensitizers for quantum-dot-sensitized solar cells (QDSCs). Alloy PbxCd1-xS QDs (Pb0.54Cd0.46S, Pb0.31Cd0.69S, and Pb0.24Cd0.76S) were found to substantially improve the photocurrent of the solar cells compared to the single CdS or PbS QDs. Moreover, it was found that the photocurrent increases and the photovoltage decreases when the ratio of Pb in PbxCd1-xS is increased. Without surface protecting layer deposition, the highest short-circuit current density reaches 20 mA/cm(2) under simulated AM 1.5 illumination (100 mW/cm(2)). After an additional CdS coating layer was deposited onto the PbxCd1-xS electrode, the photovoltaic performance further improved, with a photocurrent of 22.6 mA/cm(2) and an efficiency of 3.2%.
|
|
| 46. |
- Yuan, Chunze, et al.
(författare)
-
Simultaneous Multiple Wavelength Upconversion in a Core-Shell Nanoparticle for Enhanced Near Infrared Light Harvesting in a Dye-Sensitized Solar Cell
- 2014
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 6:20, s. 18018-18025
-
Tidskriftsartikel (refereegranskat)abstract
- The efficiency of most photovoltaic devices is severely limited by near-infrared (NIR) transmission losses. To alleviate this limitation, a new type of colloidal upconversion nanoparticles (UCNPs), hexagonal core-shell-structured beta-NaYbF4:Er3+(2%)/NaYF4:Nd3+(30%), is developed and explored in this work as an NIR energy relay material for dye-sensitized solar cells (DSSCs). These UCNPs are able to harvest light energy in multiple NIR regions, and subsequently convert the absorbed energy into visible light where the DSSCs strongly absorb. The NIR-insensitive DSSCs show compelling photocurrent increases through binary upconversion under NIR light illumination either at 785 or 980 nm, substantiating efficient energy relay by these UCNPs. The overall conversion efficiency of the DSSCs was improved with the introduction of UCNPs under simulated AM 1.5 solar irradiation.
|
|
| 47. |
|
|
| 48. |
- Zhang, Jiming, et al.
(författare)
-
Early-life carbamate exposure and intelligence quotient of seven-year-old children
- 2020
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 145
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Early-life carbamate exposure during developmental period has been linked with adverse health effects and attracted attention.Methods: Three hundred and three children at age of seven were included in the current study. Urinary carbofuranphenol concentrations were measured using gas chromatography-tandem mass spectrometry. Verbal, performance and full-scale intelligence quotients (IQ(V), IQ(P), and IQ(FS)) were assessed using Wechsler Intelligence Scale for Children-Chinese Revised. Generalized linear models were used to explore the associations between carbofuranphenol levels and IQs. Generalized estimating equations were used to explore long-term health effect and sensitive time window.Results: Carbofuranphenol was detected in 96.6% of the seven-year-old urinary samples, the geometric mean, median, and inter quartile range of the carbofuranphenol concentrations were 0.67 mu g/L, 0.30 mu g/L, and 0.09-3.72 mu g/L, respectively, which were similar with the level of three-year-old children from the SMBCS cohort. Seven-year-old carbofuranphenol level was negatively associated with IQP [beta = -0.044; 95% confidence interval (CI): -0.087, -0.001; p = 0.045]. Three-year-old carbofuranphenol level was negatively associated with IQP (beta =-0.100; 95% CI: -0.186, -0.014; p= 0.022) and IQFS (beta =-0.087; 95% CI: -0.173, -0.001; p = 0.047). Carbamate exposure of maternal and children at both three and seven years old had negative associations with IQP (beta = -0.089; 95% CI: -0.171, -0.007; p = 0.034), and IQFS (beta = -0.064; 95% CI: -0.127, -0.000; p = 0.049) of children at age of seven.Conclusion: Results of the present study verify that children in an agricultural region of China were widely exposed to carbamate pesticides. Carbamate exposure in utero and at three and seven years may adversely impact children's neurodevelopment.
|
|
| 49. |
- Zhang, Jiming, et al.
(författare)
-
Urinary para-nitrophenol levels of pregnant women and cognitive and motor function of their children aged 2 years : Evidence from the SMBCS (China)
- 2022
-
Ingår i: Ecotoxicology and Environmental Safety. - : Academia Press. - 0147-6513 .- 1090-2414. ; 244
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Urinary para-nitrophenol (PNP), an exposure biomarker of ethyl parathion (EP) and methyl parathion (MP) pesticides, was still pervasively detected in the general population even after global restriction for years. And the concern whether there is an association of PNP level with child development of the nervous system is increasing. The current study aimed to evaluate the maternal urinary PNP concentrations during late pregnancy and the associations of PNP levels with cognitive and motor function of their children at the age of 2 years.METHODS: 323 mother-child pairs from the Sheyang Mini Birth Cohort Study were included in the current study. Gas chromatography-tandem mass spectrometry was used to measure concentrations of PNP, the specific metabolite of EP and MP, in maternal urine samples during pregnancy. Developmental quotients (DQs) scores measured with Gesell Developmental Scales were employed to evaluate cognitive and motor function of children aged 2 years. Generalized linear models were performed to analyze the associations of PNP concentrations in pregnant women's urine samples with cognitive and motor function of their children.RESULTS: Maternal PNP was detected in all urine samples with a median of 4.11 μg/L and a range from 0.57 μg/L to 109.13 μg/L, respectively. Maternal urinary PNP concentrations showed a negative trend with DQ of motor area [regression coefficient (β) = - 1.35; 95 % confidence interval (95 %CI): - 2.37, - 0.33; P < 0.01], and the children whose mothers were in the fourth quartile exposure group performed significantly worse compared to the reference group (β = - 1.11; 95 %CI: - 1.80, - 0.42; P < 0.01). As for average DQ score, children with their mothers' urinary PNP concentrations in the third quartile group had higher scores than those in the first quartile group (β = 0.39; 95 %CI: 0.03, 0.75; P = 0.04). In sex-stratified analyses, a negative trend between maternal urinary PNP concentrations and DQ scores in motor area of children was only observed in boys (β = - 1.62; 95 %CI: - 2.80, - 0.43; P < 0.01). Boys in the third quartile group had higher DQ average scores than those in the lowest quartile as reference (β = 0.53; 95 %CI: 0.02, 1.04; P = 0.04).CONCLUSIONS: The mothers from SMBCS may be widely exposed to EP and/or MP, which were associated with the cognitive and motor function of their children aged 2 years in a sex-specific manner. Our results might provide epidemiology evidence on the potential effects of prenatal exposure to EP and/or MP on children's cognitive and motor function.
|
|
| 50. |
- Zhang, Longbin, et al.
(författare)
-
Ankle Joint Torque Estimation Using an EMG-Driven Neuromusculoskeletal Model and an Artificial Neural Network Model
- 2021
-
Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1545-5955 .- 1558-3783. ; 18:2, s. 564-573
-
Tidskriftsartikel (refereegranskat)abstract
- In recent decades, there has been an increasing interest in the use of robotic powered exoskeletons to assist patients with movement disorders in rehabilitation and daily life. Providing assistive torque that compensates for the user’s remaining muscle contributions is a growing and challenging field within exoskeleton control. In this article, ankle joint torques were estimated using electromyography (EMG)-driven neuromusculoskeletal (NMS) model and an artificial neural network (ANN) model in seven movement tasks, including fast walking, slow walking, self-selected speed walking, and isokinetic dorsi/plantar flexion at 60◦/s and 90◦/s . In each method, EMG signals and ankle joint angles were used as input, the models were trained with data from 3-D motion analysis, and ankle joint torques were predicted. Six cases using different motion trials as calibration (for the NMS model)/training (for the ANN) were devised, and the agreement between the predicted and measured ankle joint torques was computed. We found that the NMS model could overall better predict ankle joint torques from EMG and angle data than the ANN model with some exceptions; the ANN predicted ankle joint torques with better agreement when trained with data from the same movement. The NMS model predicted ankle joint torque best when calibrated with trials during which EMG reached maximum levels, whereas the ANN predicted well when trained with many trials and types of movements. In addition, the ANN prediction may become less reliable when predicting unseen movements. Detailed comparative studies of methods to predict ankle joint torque are crucial for determining strategies for exoskeleton control. Note to Practitioners—In exoskeleton control for strength augmentation applied in military, industry, and healthcare applications, providing assistive torque that compensates for the user’s remaining muscle contributions, is a challenging problem. This article predicted the ankle joint torques by electromyography (EMG)-driven neuromusculoskeletal (NMS) model and an artificial neural network (ANN) model in different movements. To the best of our knowledge, this is the first study comparing joint torque prediction performance of EMG-driven model to ANN. In the EMG-driven NMS model, mathematical equations were formulated to reproduce the transformations from EMG signal generation and joint angles to musculotendon forces and joint torques. A three-layer ANN was constructed with an adaptive moment estimation (Adam) optimization method to learn the relationships between the inputs (EMG signals and joint angles) and the outputs (joint torques). In the experiments, we estimated ankle joint torques in gait and isokinetic movements and compared the performance of methods to predict ankle joint torque, relating to how the methods have been calibrated/trained. The detailed analysis of the methods’ performance in predicting ankle joint torque can significantly contribute to determining which model to choose, and under which circumstances, and, thus, be of great benefit for exoskeleton rehabilitation controller design.
|
|
