Distortion of DNA Origami on Graphene Imaged with Advanced TEM Techniques

While graphene may appear to be the ultimate support membrane for transmission electron microscopy (TEM) imaging of DNA nanostructures, very little is known if it poses an advantage over conventional carbon supports in terms of resolution and contrast. Microscopic investigations are carried out on DNA origami nanoplates that are supported onto freestanding graphene, using advanced TEM techniques, including a new dark-field technique that is recently developed in our lab. TEM images of stained and unstained DNA origami are presented with high contrast on both graphene and amorphous carbon membranes. On graphene, the images of the origami plates show severe unwanted distortions, where the rectangular shape of the nanoplates is significantly distorted. From a number of comparative control experiments, it is demonstrated that neither staining agents, nor screening ions, nor the level of electron-beam irradiation cause this distortion. Instead, it is suggested that origami nanoplates are distorted due to hydrophobic interaction of the DNA bases with graphene upon adsorption of the DNA origami nanoplates.BN/Cees Dekker LabBN/Technici en AnalistenQN/AfdelingsbureauQN/Zandbergen La

The accumulation of heavy metals in agricultural land and the associated potential ecological risks in Shenzhen, China

Accumulation of heavy metals in agricultural land and their ecological risks are key issues in soil security studies. This study investigated the concentrations of six heavy metals-copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr) in Shenzhen's agricultural lands and examined the potential hazards and possible sources of these metals. Eighty-two samples from agricultural topsoil were collected. Potential ecological risk index was used to calculate the potential risk of heavy metals. Principal component analysis (PCA) was applied to explore pollution sources of the metals. Finally, Kriging was used to predict the spatial distribution of the metals' potential ecological risks. The concentrations of the heavy metals were higher than their background values. Most of them presented little potential ecological risk, except for the heavy metal cadmium (Cd). Four districts (Longgang, Longhua, Pingshan, and Dapeng) exhibited some degree of potential risk, which tended to have more industries and road networks. Three major sources of heavy metals included geochemical processes, industrial pollutants, and traffic pollution. The heavy metal Cd was the main contributor to the pollution in agricultural land during the study period. It also poses the potential hazard for the future. High potential risk is closely related to industrial pollution and transportation. Since the 1980s, the sources of heavy metals have evolved from parent rock weathering, erosion, degradation of organics, and mineralization to human disturbances resulting in chemical changes in the soil

Internet addiction of adolescents in China: Prevalence, predictors, and association with well-being

Internet addiction is a mental health problem that affects a significant number of people worldwide. Our study attempted to investigate the prevalence of Internet addiction among Chinese adolescents and to explore the predictors of Internet addiction and its association with well-being. A total of 10,988 adolescents from nine different cities in China were surveyed using the Diagnostic Questionnaire (DQ) for Internet addiction, the Center for Epidemiologic Studies Depression Scale, the Rosenberg Self-esteem Scale, and the Adolescent's Satisfaction with Life Scale. The mean age of the whole sample was 17.2 years (ranging from 13 to 23 years). The prevalence rate of Internet addiction among the surveyed adolescents was 7.5%, which was influenced by gender and grade (chi(2) = 74.027, p < 0.001; chi(2) = 7.162, p < 0.05). The breadth of extracurricular activities, the age when people used Internet for the first time, and whether people used Internet for the first time in Internet bar were significant predictors of Internet addiction (beta = -0.065, p < 0.001; beta = -0.101, p < 0.001; beta = 0.545, p < 0.001). Finally, our study found evidence demonstrating the link between Internet addiction and well-being. Increased symptoms of problematic use were associated with decreased self-esteem (F = 258.344, p < 0.001), satisfaction with life (F = 232.428, p < 0.001), and increased depression (F = 607.062, p < 0.001)

Characterization of two thymosins as immune-related genes in common carp (Cyprinus carpio L.)

Prothymosin alpha (ProT alpha) and thymosin beta (T beta) belong to thymosin family, which consists of a series of highly conserved peptides involved in stimulating immune responses. ProT alpha b and T beta are still poorly studied in teleost. Here, the full-length cDNAs of ProT alpha b and T beta-like (T beta-l) were cloned and identified in common carp (Cyprinus carpi L). The expressions of carp ProT alpha b and T beta-l exhibited rise-fall pattern and then trended to be stable during early development. After spring viraemia of carp virus (SVCV) infection, the carp ProT alpha b and T beta-l transcripts were significantly up-regulated in some immune-related organs. When transiently over-expressed carp ProT alpha b and T beta-l in zebrafish, these two proteins upregulated the expressions of T lymphocytes-related genes (Rag 1, TCR-gamma, CD4 and CD8 alpha). These results suggest that carp ProT alpha b and T beta may ultimately enhance the immune response during viral infection and modulate the development of T lymphocytes in teleost. (C) 2015 Elsevier Ltd. All rights reserved

The effect of Internet use on adolescents' lifestyles: A national survey

Computer and Internet technology continues to influence people&#39;s lives, especially those of adolescents. The aim of this study was to explore the association between Internet use and adolescents&#39; lifestyles. With data from a cross-sectional survey conducted in China in 2009, a model revealing the effects of Internet use on adolescents&#39; lifestyles was established from a series of hierarchical regression analyses. The model shows that certain Internet habits, such as excessive online time, accessing the Internet in an Internet bar, and using the Internet for catharsis, are related to poor lifestyle habits in adolescents; however, using the Internet for purposes such as gaining knowledge and finding information positively predicts healthy lifestyles in adolescents. Implications regarding the relationship between Internet use and the lifestyles of adolescents are discussed. (C) 2012 Published by Elsevier Ltd

Characteristics and clinical correlates of prospective memory performance in first-episode schizophrenia

Objective: The aim of this study was to examine prospective memory (PM) and its socio-demographic, clinical, and neurocognitive correlates in first episode schizophrenia (FES). Methods: Fifty-one FES patients and 42 healthy controls formed the study sample. Time- and event-based PM (TBPM and EBPM) performance were measured with the Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT). A battery of neuropsychological tests was also administered. Patients' clinical symptoms were evaluated with the Positive and Negative Symptom Scale (PANSS). Results: Patients performed significantly worse in both TBPM (8.7. ±. 5.3 vs. 14.8. ±. 3.5) and EBPM (11.3. ±. 4.7 vs. 15.7. ±. 2.7) than the controls. After controlling for age, gender, education level and neurocognitive test score, the difference in performance on the two types of PM tasks between patients and controls was no longer present. In multiple linear regression analyses, longer duration of untreated psychosis (DUP), lower scores of the Hopkins Verbal Learning Test-Revised (HVLT-R) and the categories completed of the Wisconsin Card Sorting Test (WCST-CC) and higher score of the Color Trails Test-2 (CTT-2) contributed to poorer TBPM performance, while lower score of HVLT-R, higher score of the perseverative errors of the Wisconsin Card Sorting Test (WCST-PE) and longer DUP contributed to worse performance on EBPM. Conclusions: Both subtypes of PM are impaired in first-episode schizophrenia suggesting that PM deficits are an integral part of the cognitive dysfunction in the disease process. © 2011 Elsevier B.V.link_to_subscribed_fulltex

Characteristics and clinical correlates of prospective memory performance in first-episode schizophrenia

Objective: The aim of this study was to examine prospective memory (PM) and its socio-demographic, clinical, and neurocognitive correlates in first episode schizophrenia (FES)

Characteristics and clinical correlates of prospective memory performance in first-episode schizophrenia

Objective: The aim of this study was to examine prospective memory (PM) and its socio-demographic, clinical, and neurocognitive correlates in first episode schizophrenia (FES)

Two new withanolides from the halophyte Datura stramonium L.

Eight steroids, including five withanolides (1-5) and three other ergostane-type steroids (6-8), were isolated from the aerial parts of the halophyte Datura stramonium L., which were collected from the Yellow River Delta in China. Their structures were elucidated on the basis of extensive spectroscopic methods, especially 1D and 2D NMR techniques. Compounds 1 and 2 were new compounds and characterised as (22R)-27-hydroxy-7-methoxy-1-oxowitha-3,5,24-trienolide and its 27-O--d-glucopyranoside. Compound 3 was a new natural product and identified as (22R)-27-hydroxy-1-oxowitha-2,5,24-trienolide and isolated from nature for the first time.Eight steroids, including five withanolides (1-5) and three other ergostane-type steroids (6-8), were isolated from the aerial parts of the halophyte Datura stramonium L., which were collected from the Yellow River Delta in China. Their structures were elucidated on the basis of extensive spectroscopic methods, especially 1D and 2D NMR techniques. Compounds 1 and 2 were new compounds and characterised as (22R)-27-hydroxy-7-methoxy-1-oxowitha-3,5,24-trienolide and its 27-O--d-glucopyranoside. Compound 3 was a new natural product and identified as (22R)-27-hydroxy-1-oxowitha-2,5,24-trienolide and isolated from nature for the first time