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1.
ACS Omega ; 9(23): 24299-24307, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38882089

ABSTRACT

In semiconductor manufacturing, the sublimation drying process is crucial but poorly understood-particularly regarding the solidification of agents such as cyclohexanol on Si substrates. This knowledge gap results in inconsistent film properties and risks such as structural collapse. To address this critical gap in knowledge, the present study focused on an in-depth examination of the nucleation behavior exhibited by cyclohexanol during its cooling and solidification on Si substrates. Using a digital camera (GoPro10), the solidification process in experiments was recorded for a range of cooling rates and using substrates with distinct surface patterns. To evaluate temporal changes in crystal nucleation, video images were visually checked, and the temporal changes in the number of nuclei were examined. For a more quantitative analysis, the least-squares method was successfully employed to correlate mathematical equations to time-dependent nucleation data. Interestingly, the outcomes revealed significant correlations between the nucleation rate, cooling rate, and substrate pattern. In summary, this research offers a robust experimental framework for understanding the complex solidification behavior of cyclohexanol on Si substrates. The study contributes both qualitative and quantitative analyses, enriching our understanding of the variables that govern the solidification process, which has significant implications for enhancing the overall reliability and efficiency of semiconductor manufacturing.

2.
Environ Sci Ecotechnol ; 21: 100422, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38746775

ABSTRACT

Remediating soil contaminated with polycyclic aromatic hydrocarbons (PAHs) presents a significant environmental challenge due to their toxic and carcinogenic properties. Traditional PAHs remediation methods-chemical, thermal, and bioremediation-along with conventional soil-washing agents like surfactants and cyclodextrins face challenges of cost, ecological harm, and inefficiency. Here we show an effective and environmentally friendly calixarene derivative for PAHs removal through soil washing. Thiacalix[4]arene tetrasulfonate (TCAS) has a unique molecular structure of a sulfonate group and a sulfur atom, which enhances its solubility and facilitates selective binding with PAHs. It forms host-guest complexes with PAHs through π-π stacking, OH-π interactions, hydrogen bonding, van der Waals forces, and electrostatic interactions. These interactions enable partial encapsulation of PAH molecules, aiding their desorption from the soil matrix. Our results show that a 0.7% solution of TCAS can extract approximately 50% of PAHs from contaminated soil while preserving soil nutrients and minimizing adverse environmental effects. This research unveils the pioneering application of TCAS in removing PAHs from contaminated soil, marking a transformative advancement in resource-efficient and sustainable soil remediation strategies.

3.
Langmuir ; 40(8): 4033-4043, 2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38356265

ABSTRACT

Sublimation drying is used in the drying process of semiconductor device manufacturing. However, the solidification behavior mechanics of sublimation agents on substrates has not been clarified. Therefore, the properties of solidified films within substrate surfaces can become nonuniform, leading to their collapse. This study aimed to analyze the interface growth behavior during the cooling and solidification of a water/ice system as a basic case and to clarify the dynamic mechanism of the solidification behavior of liquid films on Si substrates. The solidification behavior of a water/ice system on Si substrates was captured on a video at different cooling rates. The recorded video was subjected to a digital image analysis to examine the crystal morphology and quantify the interface growth rate. The least-squares method with kinetic formulas was used to evaluate the feasibility of fitting the temperature variation to the interface growth rate. A visual examination of the morphology of interfacial growth revealed that it can be classified into four morphologies. The proposed kinetic equation describes the experimental results regarding the temperature dependence of the interfacial growth rate. Through image analysis, the interface growth rate of water and ice was quantified, and an evaluation formula was proposed.

4.
Int J Cancer ; 154(3): 465-476, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-37707172

ABSTRACT

China accounted for 45.3% of new cases of primary liver cancer (PLC) worldwide in 2020. While variations in PLC incidence between different regions of China and decreasing incidence in overall China have been reported, incidence patterns have not been thoroughly explored by region. We examined the nearly status and temporal trends of PLC incidence in different geographical regions in China and project future trends. The age-standardized incidence rate (ASR) was estimated for 1978 to 2012 by different geographical regions and gender in China. Age-period-cohort model was adopted to evaluate age and birth cohort effects on the temporal trend of five registries of China (Hong Kong, Shanghai, Jiashan, Harbin and Zhongshan), Bayesian age-period-cohort model was adopted to project future trends for 2013 to 2032. PLC incidence in China exhibits marked geographical disparity, with the highest incidence in Southwest China, and gender differences being particularly pronounced in South China. While other registries exhibited decreasing trend, Zhongshan exhibited an increasing trend, with the cohort effect showing a marked upward trend for females born in 1916 to 1949 and males born in 1916 to 1962. During 2013 to 2032, the ASR appears to increase by 86.9% for men and 40.0% for women in Zhongshan, while the remaining registries will decline by around 50%. Since the high incidence of hepatitis B virus infection in early birth cohort, recent rise of nonviral risk factors and the severe aging of the Chinese population, it may be critical to tailor future prevention and control strategies for PLC to the distribution of risk factors in different geographical regions.


Subject(s)
Liver Neoplasms , Male , Humans , Female , Aged, 80 and over , Incidence , China/epidemiology , Bayes Theorem , Cohort Studies , Registries , Liver Neoplasms/epidemiology
5.
J Psychosom Res ; 173: 111466, 2023 10.
Article in English | MEDLINE | ID: mdl-37647831

ABSTRACT

PURPOSE: The relationship between quality of life (QoL) and long-term prognosis in stroke patients is still unclear. We explored physical and mental QoL trajectories during the first six months after stroke and determined the associations between trajectories and long-term prognosis in patients with first-ever ischemic stroke. METHODS: Included were 733 participants from a prospective study. QoL was assessed with the 12-item Short Form Survey (SF-12) at baseline, 3 and 6 months. Patients' prognoses (stroke recurrence and death) were identified from 2010 to 2021. The latent class growth model (LCGM) was used to identify distinct trajectories of physical and mental QoL measured over the first 6 months. We employed the Cox model or Fine-Gray model for prognoses to examine the associations between QoL trajectories and prognosis. RESULTS: Five trajectories of physical QoL and five trajectories of mental QoL were identified. For physical QoL of the Poor-Improved, and Moderate-Impaired trajectory versus Moderate-Improved trajectory, the hazard ratio (HR) for death was 2.39 (1.14 to 5.02), and 2.03(0.93 to 4.44); the HR for recurrence was 1.56 (0.83 to 2.94) and 2.33 (1.28 to 4.24). For mental QoL of the Moderate-Impaired trajectory versus the Moderate-Improved trajectory, the HR for death was 2.48 (1.21 to 5.07). The results were robust in the sensitivity analysis. CONCLUSION: QoL during the first six months after ischemic stroke can be categorized into distinct groups. Change in QoL was associated with long-term survival. Secondary prevention of recurrent strokes might rely more on improving patients' physical QoL.


Subject(s)
Ischemic Stroke , Stroke , Humans , Quality of Life , Prospective Studies , Stroke/complications , Prognosis
6.
BMC Med ; 21(1): 170, 2023 05 04.
Article in English | MEDLINE | ID: mdl-37143087

ABSTRACT

BACKGROUND: Both depression and breast cancer (BC) contribute to a substantial global burden of morbidity and mortality among women, and previous studies have observed a potential depression-BC link. We aimed to comprehensively characterize the phenotypic and genetic relationships between depression and BC. METHODS: We first evaluated phenotypic association using longitudinal follow-up data from the UK Biobank (N = 250,294). We then investigated genetic relationships leveraging summary statistics from the hitherto largest genome-wide association study of European individuals conducted for depression (N = 500,199), BC (N = 247,173), and its subtypes based on the status of estrogen receptor (ER + : N = 175,475; ER - : N = 127,442). RESULTS: Observational analysis suggested an increased hazard of BC in depression patients (HR = 1.10, 95%CIs = 0.95-1.26). A positive genetic correlation between depression and overall BC was observed ([Formula: see text] = 0.08, P = 3.00 × 10-4), consistent across ER + ([Formula: see text] = 0.06, P = 6.30 × 10-3) and ER - subtypes ([Formula: see text] = 0.08, P = 7.20 × 10-3). Several specific genomic regions showed evidence of local genetic correlation, including one locus at 9q31.2, and four loci at, or close, to 6p22.1. Cross-trait meta-analysis identified 17 pleiotropic loci shared between depression and BC. TWAS analysis revealed five shared genes. Bi-directional Mendelian randomization suggested risk of depression was causally associated with risk of overall BC (OR = 1.12, 95%Cis = 1.04-1.19), but risk of BC was not causally associated with risk of depression. CONCLUSIONS: Our work demonstrates a shared genetic basis, pleiotropic loci, and a putative causal relationship between depression and BC, highlighting a biological link underlying the observed phenotypic relationship; these findings may provide important implications for future studies aimed reducing BC risk.


Subject(s)
Breast Neoplasms , Humans , Female , Breast Neoplasms/epidemiology , Breast Neoplasms/genetics , Depression/epidemiology , Depression/genetics , Genome-Wide Association Study , Risk , Receptors, Estrogen/genetics , Mendelian Randomization Analysis , Polymorphism, Single Nucleotide/genetics
7.
BMC Geriatr ; 22(1): 750, 2022 09 14.
Article in English | MEDLINE | ID: mdl-36104686

ABSTRACT

BACKGROUND: Previous studies exploring usual alcohol consumption and falls risk were scarce in China. In addition, the dose-response relationship has not been explored so far. This study aims to estimate the association between usual alcohol consumption and risk of falls among middle-aged and older Chinese adults based on data from the China Health and Retirement Longitudinal Study (CHARLS), which is representative of the population of the entire country. METHODS: Baseline survey data in 2015 and follow-up data in 2018 in CHARLS were utilized. Alcohol consumption was calculated in grams per day (gr/day) according to self-reported drinking data and categorized accordingly to The Dietary Guidelines for Chinese Residents (DGC) 2016. Fall was obtained from self-reported information. Multivariable logistic regression analyses were performed to estimate the association of usual alcohol consumption with risk of falling. The dose-response relationship was also explored using restricted cubic splines. RESULTS: A total of 12,910 middle-aged and older participants were included from the CHARLS 2015, of which 11,667 were followed up in 2018. We found that former, moderate, and excessive drinkers were at higher fall risk compared to never drinkers (former: OR, 1.24; 95% CI, 1.05-1.46; moderate: OR, 1.22; 95% CI, 1.06-1.41; excessive: OR, 1.36; 95% CI, 1.15-1.61) in the longitudinal analysis. Similarly, individuals with moderate and excessive alcohol consumption were at increased risk of falling in the cross-sectional analysis (moderate: OR, 1.18; 95% CI, 1.02-1.37; excessive: OR, 1.32; 95% CI, 1.11,1.57). No significant increased risk of falls was found for former drinkers (former: OR, 1.13; 95% CI, 0.96-1.34). We observed a significant non-linear relationship. CONCLUSIONS: Our study suggests that usual alcohol consumption was associated with a higher risk of falls, highlighting the key role of alcohol intake on the fall risk, which needed consideration in developing intervention and prevention strategies for reducing falls among middle-aged and older Chinese adults.


Subject(s)
Accidental Falls , Alcohol Drinking , Accidental Falls/prevention & control , Aged , Alcohol Drinking/adverse effects , Alcohol Drinking/epidemiology , China/epidemiology , Cross-Sectional Studies , Humans , Longitudinal Studies , Middle Aged
8.
Cancer Causes Control ; 33(10): 1247-1259, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35916964

ABSTRACT

PURPOSE: Lung cancer incidences tend to be higher among males than females in both China and the United States, yet secular incidence patterns are different due to distinct population and environmental exposures. We examined long-term and future trends of lung cancer incidence, as well as the associations of age, period, and cohort effects with gender disparities. METHODS: Using data from the Cancer Incidence in Five Continents from 1978 to 2012, we calculated age-standardized, age-specific incidence, and male-to-female incidence rate ratios (IRR), and conducted an age-period-cohort analysis. The average annual percentage change (AAPC) of the trends was obtained by Joinpoint Regression. Bayesian age-period-cohort analysis was also conducted to project incidences to 2032. RESULTS: In China, age-standardized incidence revealed a decreasing trend among males, but showed increasing trends among the younger age groups (30-54 years) in females. Age-standardized incidence rates of males decreased but remained stable among females from 1972 to 2012 in the United States. Male-to-female incidence rate ratios narrowed in both countries and reversed among younger birth cohorts in the United States. Gender disparities are expected to continue to diminish in both countries, and incidence among females appears to exceed that of males in the United States by around 2023-2027. CONCLUSION: Gender disparities in lung cancer incidence persist and will continue into the future in both countries, but our findings suggested that smoking may play different roles in gender disparities in lung cancer incidence between the two countries. Further population-based epidemiological studies among females in China are imperative.


Subject(s)
Lung Neoplasms , Adult , Bayes Theorem , China/epidemiology , Cohort Studies , Female , Humans , Incidence , Lung Neoplasms/epidemiology , Male , Middle Aged , United States/epidemiology
9.
J Psychosom Res ; 160: 110986, 2022 09.
Article in English | MEDLINE | ID: mdl-35905513

ABSTRACT

OBJECTIVE: To investigate the associations between trajectories of depressive symptoms and rate of cognitive decline among Chinese middle-aged and older adults. METHODS: A population-based cohort data from the Chinese Health and Retirement Longitudinal Study (CHARLS) were utilized. The cohort was followed up for 8 years and assessments of depressive symptoms and cognitive performance were conducted in 2011, 2013, 2015, and 2018. Group-based trajectory modeling (GBTM) was conducted to identify heterogeneous trajectories of depressive symptoms. Linear mixed models (LMMs) were performed to examine the associations between trajectories of depressive symptoms and rate of decline in global cognitive function, episodic memory, and executive function. RESULTS: Among 9264 middle-aged and older adults, five depressive symptoms trajectory groups were determined: constantly low (n = 3206, 34.6%), constantly medium (n = 3747, 40.5%), increasing (n = 899, 9.7%), decreasing (n = 929, 10.0%), and constantly high (n = 483, 5.2%). Individuals with increasing depressive symptoms exhibited the fastest decline in global cognitive function and episodic memory, followed by participants reporting constantly high or medium depressive symptoms. A significantly higher rate of decline in executive function was only observed among subjects who had increasing depressive symptoms in comparison with their counterparts with constantly low depressive symptoms. There was no significant difference in rate of cognitive decline between individuals with decreasing depressive symptoms and those demonstrating constantly low depressive symptoms. CONCLUSION: Increasing depressive symptoms co-occurred with the steepest cognitive decline among Chinese middle-aged and older adults, which potentially suggested that interventions targeting to alleviating cognitive decline should be given priority among individuals with deterioration of depressive symptoms.


Subject(s)
Cognitive Dysfunction , Depression , Aged , China/epidemiology , Cognition , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/psychology , Depression/epidemiology , Depression/psychology , Humans , Longitudinal Studies , Middle Aged
10.
Article in English | MEDLINE | ID: mdl-35835451

ABSTRACT

Silicon (Si), a high-capacity lithium-ion battery anode material, has aroused wide attention. Its further practical application has been limited by its huge volume change during the cycle. To reduce this defect, the double cross-linked product of glycinamide hydrochloride modified poly(acrylic acid) (PAG) and epoxidized natural rubber (ENR) was developed as a water-based binder to obtain sufficient elasticity and a sufficiently strong adhesive force. Due to the double cross-linked structures in the system, the binder was enabled to effectively disperse and transfer the stress generated by the volume expansion of the Si particles and keep the integrity of the electrode during the cycle, thus obtaining excellent cycle performance. When the current density was 1 A g-1, PE55 (PAG: ENR = 1:1 cross-linked polymer) electrode still achieved a specific capacity of 2322.2 mAh g-1 after 100 cycles of constant current charge and discharge, and PE55 binder exhibited excellent bonding properties (4.45 N) and mechanical properties (stress: 5.51 MPa, strain: 87.4%). The comparison of poly(acrylic acid) (PAA) electrodes suggests that the introduction of elastic polymer and the construction of double cross-linked structures can increase the stability of Si anodes.

12.
Front Public Health ; 10: 998174, 2022.
Article in English | MEDLINE | ID: mdl-36684904

ABSTRACT

Introduction: Since 2006, the human papillomavirus (HPV) vaccine has been recommended for females aged 9-26 years in the United States. Aiming to evaluate the early effect of the HPV vaccine on cervical cancer, this study assessed the incidence of cervical cancer by age and histology before and after the introduction of HPV vaccination. Methods: Data on cervical cancer incidence from 1975-2019 were extracted from the Surveillance, Epidemiology, and End Results Program. Joinpoint regression was used to determine temporal trends over time. Future cervical cancer incidence (2015-2039) was projected using Bayesian age-period-cohort analysis. Age-period-cohort (APC) models were created to evaluate age, period, and cohort effects. Results: For overall cervical cancer and cervical squamous cell carcinoma (SCC), incidence rate showed decreasing trends (-0.7%, and -1.0% annually, respectively), whereas cervical adenocarcinoma (AC) incidence continuously increased (2.6% annually). The incidence trends for AC were stable in the 20-24 and 25-29-year age groups, whereas there was an increasing trend in older age groups. Similarly, the projected trend for AC in females aged 20-30 years exhibited a decline, whereas an increase was predicted in the 31-40-year age group, especially in the 35-44 year age group. The birth cohort and period effects in SCC and AC were extracted from APC models. Discussion: During the period of 1975-2019, the incidence of cervical AC remained almost unchanged in the age groups receiving HPV vaccines while increased in the age groups not receiving HPV vaccines. The birth cohort effects of SCC and AC of the cervix provided evidence supporting the effectiveness of the HPV vaccine in preventing cervical cancer.


Subject(s)
Papillomavirus Infections , Papillomavirus Vaccines , Uterine Cervical Neoplasms , Female , Humans , United States/epidemiology , Aged , Adult , Uterine Cervical Neoplasms/epidemiology , Uterine Cervical Neoplasms/prevention & control , Human Papillomavirus Viruses , Papillomavirus Infections/complications , Papillomavirus Infections/epidemiology , Papillomavirus Infections/prevention & control , SEER Program , Papillomavirus Vaccines/therapeutic use , Bayes Theorem
13.
Cancer Causes Control ; 32(10): 1095-1105, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34152517

ABSTRACT

PURPOSE: An increasing incidence of thyroid cancer has been seen in China during the past several decades. The aim of this study was to analyze potential age, period, and cohort effects on the incidence of thyroid cancer in mainland China and to predict new cases up to 2032. METHODS: We calculated age-adjusted and age-specific incidence rates of thyroid cancer, conducted an age-period-cohort analysis of 35,037 thyroid cancer incidence cases reported to Cancer Incidence in Five Continents from 1983 to 2012 in mainland China, and predicted incidence up to 2032 using the Bayesian age-period-cohort method. RESULTS: The age-adjusted overall incidence rate of thyroid cancer increased from 1.93/100,000 in 1983-1987 to 12.18/100,000 in 2008-2012 among females and from 0.77/100,000 in 1983-1987 to 3.89/100,000 in 2008-2012 among males, with a female-to-male ratio of approximately 3.0 during the three decades. Strong birth cohort and period effects on the incidence of thyroid cancer were observed for both sexes, and such an increasing trend is predicted to continue for at least the next 20 years. More than 3.7 million new cases are projected in the 2028-2032 period. CONCLUSION: The increasing trend of thyroid cancer in mainland China will cause a great burden in the future. In addition to the potential impact of improvement in medical diagnostics, potential exposure to risk factors have played a role in the observed rising trend. Further population-based epidemiologic studies are required to identify risk factors to aid in thyroid cancer prevention and control.


Subject(s)
Thyroid Neoplasms , Bayes Theorem , China/epidemiology , Female , Forecasting , Humans , Incidence , Male , Thyroid Neoplasms/epidemiology
14.
Polymers (Basel) ; 13(5)2021 Mar 04.
Article in English | MEDLINE | ID: mdl-33806605

ABSTRACT

The viscoelastic behavior and reinforcement mechanism of polyethylene glycol (PEG) as an interfacial modifier in green tire tread composites were investigated in this study. The results show a clear positive effect on overall performance, and it significantly improved all the parameters of the "magic triangle" properties, the abrasion resistance, wet grip and ice traction, as well as the tire rolling resistance, simultaneously. For the preparation of the compounds, two mixing steps were used, as PEG 4000 was added on the second stage in order to avoid the competing reaction between silica/PEG and silanization. Fourier transform infrared spectroscopy (FTIR) confirmed that PEG could cover the silanol groups on the silica surface, resulting in the shortening of cure times and facilitating an increase of productivity. At low content of PEG, the strength was enhanced by the improvement of silica dispersion and the slippage of PEG chains, which are chemically and physically adsorbed on silica surface, but the use of excess PEG uncombined with silica in the compound, i.e., 5 phr, increases the possibility to shield the disulfide bonds of bis(3-(triethoxysilyl)-propyl) tetrasulfide (TESPT), and, thus, the properties were deteriorated. A constrained polymer model was proposed to explain the constrained chains of PEG in the silica-loaded composites on the basis of these results. An optimum PEG content is necessary for moderately strong matrix-filler interaction and, hence, for the enhancement in the mechanical properties.

15.
PLoS One ; 14(6): e0208292, 2019.
Article in English | MEDLINE | ID: mdl-31199806

ABSTRACT

OBJECTIVE: Many studies focused on reasons behind the increasing incidence and the spread of human brucellosis in mainland China, yet most of them lacked comprehensive consideration with quantitative evidence. Hence, this study aimed to further investigate the epidemic mechanism and associated factors of human brucellosis so as to provide thoughts for future countermeasures in China and the rest of the world. METHODS: Data of human brucellosis incidence and some associated factors in economy, animal husbandry, transportation as well as health and hygiene were collected at provincial level from 2005-2016. Time series plots were first used to visualize the annual incidence and annual rate of change of human brucellosis for each province, then cluster analysis categorized all the 31 provinces of mainland China based on their incidence time series during the study period. In addition, according to the characteristics of data, the dynamic panel data model in combination with supervised principal component analysis was proposed to explore effects of associated factors on human brucellosis. RESULTS: 1. The incidence rate of human brucellosis in mainland China increased three-fold from 1.41 per 100,000 people in 2005 to 4.22 per 100,000 people in 2014, though it went down a little in 2015 and 2016. Incidence rates in the north have always been higher than those in the south, but the latter also experienced an upward trend especially between 2012 and 2016. 2. The 31 provinces of mainland China were categorized into three clusters, and each cluster had its own characteristics of incidence time series. 3. The impact of health and hygiene situations on the prevention and control work of human brucellosis was still very limited and trivial (regression coefficient = -0.02). Therefore, it was plausible to presume that improving the personal average number of medical institutes and the proportion of rural medical expenditure might be helpful in preventing and controlling human brucellosis. CONCLUSIONS: The epidemic status of human brucellosis has changed in both spatial and temporal dimensions in recent years in mainland China. Apart from traditional control measures, more attention should be paid to the improvement of medical healthcare especially in rural areas in the hope of enhancing the control effect.


Subject(s)
Brucellosis/epidemiology , Cluster Analysis , Spatial Analysis , Time Factors , Brucellosis/etiology , Brucellosis/prevention & control , China/epidemiology , Cross-Sectional Studies , Delivery of Health Care , Humans , Incidence , Principal Component Analysis
16.
Nanotechnology ; 27(39): 395706, 2016 Sep 30.
Article in English | MEDLINE | ID: mdl-27573680

ABSTRACT

Recently, carbon dots (CDs) have been playing an increasingly important role in industrial production and biomedical field because of their excellent properties. As such, finding an efficient method to quickly synthesize a large scale of relatively high purity CDs is of great interest. Herein, a facile and novel microwave method has been applied to prepare nitrogen doped CDs (N-doped CDs) within 8 min using L-glutamic acid as the sole reaction precursor in the solid phase condition. The as-prepared N-doped CDs with an average size of 1.64 nm are well dispersed in aqueous solution. The photoluminescence of N-doped CDs is pH-sensitive and excitation-dependent. The N-doped CDs show a strong blue fluorescence with relatively high fluorescent quantum yield of 41.2%, which remains stable even under high ionic strength. Since the surface is rich in oxygen-containing functional groups, N-doped CDs can be applied to selectively detect Fe(3+) with the limit of detection of 10(-5) M. In addition, they are also used for cellular bioimaging because of their high fluorescent intensity and nearly zero cytotoxicity. The solid-phase microwave method seems to be an effective strategy to rapidly obtain high quality N-doped CDs and expands their applications in ion detection and cellular bioimaging.


Subject(s)
Microwaves , Carbon , Iron , Nitrogen , Oxygen , Quantum Dots
17.
Nanoscale ; 7(38): 15915-23, 2015 Oct 14.
Article in English | MEDLINE | ID: mdl-26364977

ABSTRACT

The desired control of particle size, doping element composition, and surface structure of carbon dots (CDs) are vital for understanding the fluorescence mechanism and exploring their potential applications. Herein, nitrogen-doped CDs (N-doped CDs) have been synthesized with tartaric acid and various alkylol amines (monoethanolamine, biethanolamine and triethanolamine) under microwave irradiation. A systematic investigation was performed to characterize the N-doped CDs. It is found that with increasing nitrogen proportion, the fluorescent quantum yield and lifetime of N-doped CDs increases, whereas cell toxicity decreases. In other words, N-doped CDs synthesized by tartaric acid and monoethanolamine have the highest nitrogen content, the highest fluorescent quantum yield, the longest lifetime and the lowest cell toxicity. A corresponding mechanism has been proposed. Moreover, as-synthesized N-doped CDs have been applied for selectively detecting the Fe(3+) ion and writing letters as a fluorescent ink.

18.
Nanoscale ; 7(23): 10527-34, 2015 Jun 21.
Article in English | MEDLINE | ID: mdl-26015172

ABSTRACT

Carbon quantum dots (CQDs) are novel carbon nanomaterials and are attracting increasing interest due to their good characteristics such as hydrophilicity, chemical stability, quantum yield, small particle sizes, and low cytotoxicity. Herein, we used CQDs as stabilizers and exfoliation agents to exfoliate graphite to graphene in an aqueous medium for the first time. The functions of CQDs are to reduce the surface tension of water to match that of graphite and to make weak interactions (π-π conjugation, hydrophobic force, and the Coulomb attraction) with the graphite surface. Different characterization methods were used to evaluate the presence of layers (<5 layers) of graphene sheets with fewer defects and low oxidation. In the future, CQDs can also be good candidates to exfoliate other two-dimensional materials, such as WS2, BN, MoS2, and g-C3N4, to form two-dimensional heterostructures for a range of possible applications.

19.
Carbohydr Res ; 407: 51-4, 2015 Apr 30.
Article in English | MEDLINE | ID: mdl-25704198

ABSTRACT

We herein report an efficient synthesis of ß-glycosyl 1-ester in room-temperature ionic liquids (RTILs) promoted via silver salt and quaternary ammonium salt (PTC) with good or excellent yields. All products were isolated exclusively as the ß-anomers. Four different RTILs, eight metal salts and four quaternary ammonium salts were screened in the glycosylation reaction. The synergistic effect of C6mim·OTf, Ag2O and tetrabutylammonium iodine gave the best results. Their promotion to the system was integral. Thorough study provided insight into the catalytic activity of ionic liquid structure, metal salts and quaternary ammonium salt to these reactions. It is worth mentioning that the yield of aliphatic compound 2,3,4,6-tetra-O-acetyl-ß-D-galactopyranosyl butyrate (3l) was highly improved when using C6mim·OTf as solvent compared with the normal volatile solvents under the same catalysts. This green approach has been proved to be practical and compatible with a wide range from aliphatic to aromatic substrates.


Subject(s)
Ionic Liquids/chemistry , Quaternary Ammonium Compounds/chemistry , Salts/chemical synthesis , Catalysis , Molecular Structure , Salts/chemistry , Silver/chemistry , Temperature
20.
Nanoscale Res Lett ; 9(1): 583, 2014.
Article in English | MEDLINE | ID: mdl-25346649

ABSTRACT

We examined the toxicity of four carbon-based nanomaterials (unmodified) by using carbon quantum dots (CQDs), graphene quantum dots (GQDs), graphene oxide (GO), and single-walled carbon nanotubes (SWCNTs) to cultivate bean sprout. Results showed that the toxicity of these four carbon nanomaterials increases with the increasing of concentration and cultivating time. In addition, pH test was applied to study the effect of carbon-based nanomaterials on water. pH of culture solution displayed unconspicuous dose-dependent, but nanomaterials indeed have a considerable impact on the pH even at low concentration.

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