| 1. |
- Feng, Cun-Feng, et al.
(author)
-
Effects of average degree of network on an order-disorder transition in opinion dynamics
- 2010
-
In: Chinese Physics B. - : IOPScience. - 1674-1056. ; 19:6, s. 060203-
-
Journal article (peer-reviewed)abstract
- We have investigated the influence of the average degree (k) of network on the location of an order-disorder transition in opinion dynamics. For this purpose, a variant of majority rule (VMR) model is applied to Watts–Strogatz (WS) small-world networks and Barabási–Albert (BA) scale-free networks which may describe some non-trivial properties of social systems. Using Monte Carlo simulations, we find that the order–disorder transition point of the VMR model is greatly affected by the average degree (k) of the networks; a larger value of (k) results in a more ordered state of the system. Comparing WS networks with BA networks, we find WS networks have better orderliness than BA networks when the average degree (k) is small. With the increase of (k), BA networks have a more ordered state. By implementing finite-size scaling analysis, we also obtain critical exponents β/ν, γ/ν and 1/ν for several values of average degree (k). Our results may be helpful to understand structural effects on order–disorder phase transition in the context of the majority rule model.
|
|
| 2. |
- Backes, Claudia, et al.
(author)
-
Production and processing of graphene and related materials
- 2020
-
In: 2D Materials. - : IOP Publishing. - 2053-1583. ; 7:2
-
Journal article (peer-reviewed)abstract
- We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. Section I is devoted to 'bottom up' approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers 'top down' techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers' and modified Hummers' methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resource-consuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown. Section VIII discusses advances in GRM functionalization. A broad range of organic molecules can be anchored to the sp(2) basal plane by reductive functionalization. Negatively charged graphene can be prepared in liquid phase (e.g. via intercalation chemistry or electrochemically) and can react with electrophiles. This can be achieved both in dispersion or on substrate. The functional groups of GO can be further derivatized. Graphene can also be noncovalently functionalized, in particular with polycyclic aromatic hydrocarbons that assemble on the sp(2) carbon network by pi-pi stacking. In the liquid phase, this can enhance the colloidal stability of SLG/FLG. Approaches to achieve noncovalent on-substrate functionalization are also discussed, which can chemically dope graphene. Research efforts to derivatize CNMs are also summarized, as well as novel routes to selectively address defect sites. In dispersion, edges are the most dominant defects and can be covalently modified. This enhances colloidal stability without modifying the graphene basal plane. Basal plane point defects can also be modified, passivated and healed in ultra-high vacuum. The decoration of graphene with metal nanoparticles (NPs) has also received considerable attention, as it allows to exploit synergistic effects between NPs and graphene. Decoration can be either achieved chemically or in the gas phase. All LMs,
|
|
| 3. |
- Fan, Chuanwen, et al.
(author)
-
Mismatch repair protein deficiency and its implications on distant metastasis in colorectal cancer : A comprehensive analysis
- 2024
-
In: Cancer Medicine. - : John Wiley & Sons. - 2045-7634. ; 13:7
-
Journal article (peer-reviewed)abstract
- Background: While previous studies have indicated variability in distant metastatic potential among different mismatch repair (MMR) states in colorectal cancer (CRC), their findings remain inconclusive, especially considering potential differences across various ethnic backgrounds. Furthermore, the gene regulatory networks and the underlying mechanisms responsible for these variances in metastatic potential across MMR states have yet to be elucidated.Methods: We collected 2058 consecutive primary CRC samples from the South West of China and assessed the expression of MMR proteins (MLH1, MSH2, MSH6, and PMS2) using immunohistochemistry. To explore the inconsistencies between different MMR statuses and recurrence, we performed a meta-analysis. To delve deeper, we employed Weighted Gene Co-expression Network Analysis (WGCNA), ClueGo, and iRegulon, pinpointing gene expression networks and key regulatory molecules linked to metastasis and recurrence in CRC. Lastly, both univariate and multivariate Cox regression analyses were applied to determine the impact of core regulatory molecules on metastasis.Results: Of the samples, 8.2% displayed deficient MMR (dMMR), with losses of MLH1 and PSM2 observed in 40.8% and 63.9%, respectively. A unique 24.3% isolated loss of PMS2 without concurrent metastasis was identified, a result that diverges from established literature. Additionally, our meta-analysis further solidifies the reduced recurrence likelihood in dMMR CRC samples compared to proficient MMR (pMMR). Two gene expression networks tied to distant metastasis and recurrence were identified, with a majority of metastasis-related genes located on chromosomes 8 and 18. An IRF1 positive feedback loop was discerned in the metastasis-related network, and IRF1 was identified as a predictive marker for both recurrence-free and distant metastasis-free survival across multiple datasets.Conclusion: Geographical and ethnic factors might influence peculiarities in MMR protein loss. Our findings also highlight new gene expression networks and crucial regulatory molecules in CRC metastasis, enhancing our comprehension of the mechanisms driving distant metastasis.
|
|
| 4. |
|
|
| 5. |
- Gao, Jingfang, 1966-, et al.
(author)
-
Association of NFKBIA polymorphism with colorectal cancer risk and prognosis in Swedish and Chinese populations
- 2007
-
In: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 42:3, s. 345-350
-
Journal article (peer-reviewed)abstract
- Objective. The inhibitory proteins, IκBs, regulate the activity of nuclear factor kappa-beta (NF-κB), which is implicated in tumorigenesis by regulating expression of a variety of genes involved in cellular transformation, proliferation, invasion, angiogenesis and metastasis. Variants in the genes encoding IκBs may be involved in cancer development through the activation of NF-κB. The objective of this study was to investigate the susceptibility of an A to G variation (rs696) in the 3′ UTR of NFKBIA (encoding IκBα) to colorectal cancer (CRC) and the association of this polymorphism with clinicopathologic variables in CRC patients. Material and methods. A case-control study was carried out on a Swedish (155 CRCs, 438 controls) and a Chinese population (199 CRCs, 577 controls). The genotype of NFKBIA was determined by PCR-restriction fragment length polymorphism. Results. The frequency of the AG genotype was increased in the Chinese patients ≥50 years of age compared with the Chinese controls (odds ratio (OR) = 3.06, 95% confidence interval (CI) = 1.55-6.02, p=0.001), even when adjusted for age (OR = 3.20, 95% CI = 1.61-6.38, p=0.001). The GG genotype of NFKBIA was related to a poorer survival rate in the Swedish patients, independent of gender, age, tumour location, Dukes' stage and differentiation (hazard ratio = 3.10, 95% Cl = 1.28-7.60, p=0.01). Conclusions. Chinese individuals ≥50 years of age carrying the AG genotype of NFKBIA may be at an increased risk of developing CRC, and the GG genotype of NFKBIA may be considered as a prognostic factor for Swedish CRC patients. © 2007 Taylor & Francis.
|
|
| 6. |
- Shen, Xiao-Gang, et al.
(author)
-
Downregulation of caspase-10 predicting poor survival after resection of stage II colorectal cancer
- 2011
-
In: International Journal of Colorectal Disease. - : Springer Verlag (Germany). - 0179-1958 .- 1432-1262. ; 26:12, s. 1519-1524
-
Journal article (peer-reviewed)abstract
- Purpose The aim of this study was to evaluate the prevalence and clinical significance of caspase-10 mRNA expression in stage II colorectal cancer. less thanbrgreater than less thanbrgreater thanMethods Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze caspase-10 expression in cancer tissue and corresponding normal mucosa from 120 patients with stage II colorectal cancer. Variables were analyzed by Chi-square test or Fishers exact test. Survival was evaluated with method of Kaplan-Meier. Multivariate analysis was performed with Coxs proportional hazards model. less thanbrgreater than less thanbrgreater thanResults The expression of caspase-10 mRNA was found to be downregulated in cancer tissue compared to normal mucosa (P = 0.001). Poorly differentiated cancer showed lower mRNA expression than cancer with greater differentiation (P = 0.031). Univariate survival curves, estimated using the method of Kaplan-Meier, defined a significant association between caspase-10 expression and both overall survival (P = 0.012) and disease-free survival (P = 0.021). A multivariate analysis, performed by Coxs proportional hazards regression model, confirmed that a low caspase-10 expression was the only significant factor to predict poor prognosis in patients with stage II colorectal cancer. less thanbrgreater than less thanbrgreater thanConclusion Our data indicate that caspase-10 expression, measured by quantitative real-time RT-PCR, is a possible prognostic factor in patients with stage II colorectal cancer.
|
|
| 7. |
- Wang, Mo-Jin, et al.
(author)
-
Downregulation of microRNA-124 is an independent prognostic factor in patients with colorectal cancer
- 2013
-
In: International Journal of Colorectal Disease. - : Springer Verlag (Germany). - 0179-1958 .- 1432-1262. ; 28:2, s. 183-189
-
Journal article (peer-reviewed)abstract
- PurposeRecently, microRNA-124 (miR-124) has been demonstrated as a potential tumor suppressor in several types of cancers. However, the role of miR-124 in colorectal cancer remains unclear. This study was aimed at investigating the clinicopathological significance of miR-124 expression in colorectal cancer.MethodsQuantitative real-time PCR was used to analyze miR-124 expression in 96 colorectal cancers and individual-matched normal mucosa samples. The expression of miR-124 was assessed for associations with clinicopathological characteristics using chi-square test. The survival curves were calculated by the Kaplan–Meier method. The influence of each variable on survival was examined by the Cox multivariate regression analysis.ResultsThe miR-124 expression was significantly downregulated in colorectal cancer compared to normal mucosa (P = 0.001). In colorectal cancer, miR-124 decreased expression correlated significantly with the grade of differentiation (P = 0.021). Univariate survival analysis showed that the downregulated miR-124 was significantly correlated with worse prognosis, both in terms of overall survival (P = 0.017) and disease-free survival (DFS) (P = 0.014). Further, the downregulated miR-124 was demonstrated as a prognostic factor for overall survival (hazard ratio, HR = 4.634; 95 % confidence interval, CI, 1.731–12.404; P = 0.002) and DFS (HR = 4.533, 95 % CI 1.733–11.856, P = 0.002), independently of gender, age, location, maximum tumor size, depth of invasion, differentiation, and TNM stage.ConclusionsMiR-124 may play a certain role in the development of colorectal cancer. The downregulation expression of miR-124 is an independent prognostic factor in patients with colorectal cancer.
|
|
| 8. |
- Wang, Mo-Jin, et al.
(author)
-
The prognostic factors and multiple biomarkers in young patients with colorectal cancer
- 2015
-
In: Scientific Reports. - : Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group. - 2045-2322. ; 5:10645
-
Journal article (peer-reviewed)abstract
- The incidence of colorectal cancer (CRC) in young patients (less than= 50 years of age) appears to be increasing. However, their clinicopathological characteristics and survival are controversial. Likewise, the biomarkers are unclear. We used the West China (2008-2013, China), Surveillance, Epidemiology, and End Results program (1973-2011, United States) and Linkoping Cancer (1972-2009, Sweden) databases to analyse clinicopathological characteristics, survival and multiple biomarkers of young CRC patients. A total of 509,934 CRC patients were included from the three databases. The young CRC patients tended to have more distal location tumours, fewer tumour numbers, later stage, more mucinous carcinoma and poorer differentiation. The cancer-specific survival (CSS) of young patients was significantly better. The PRL (HR = 12.341, 95% CI = 1.615-94.276, P = 0.010), RBM3 (HR = 0.093, 95% CI = 0.012-0.712, P = 0.018), Wrap53 (HR = 1.952, 95% CI = 0.452-6.342, P = 0.031), p53 (HR = 5.549, 95% CI = 1.176-26.178, P = 0.045) and DNA status (HR = 17.602, 95% CI = 2.551-121.448, P = 0.001) were associated with CSS of the young patients. In conclusion, this study suggests that young CRC patients present advanced tumours and more malignant pathological features, while they have a better prognosis. The PRL, RBM3, Wrap53, p53 and DNA status are potential prognostic biomarkers for the young CRC patients.
|
|
| 9. |
- Yang, Lie, et al.
(author)
-
Efficacy of Surgery and Adjuvant Therapy in Older Patients With Colorectal Cancer A STROBE-compliant article
- 2014
-
In: Medicine. - : Lippincott, Williams andamp; Wilkins. - 0025-7974 .- 1536-5964. ; 93:28
-
Journal article (peer-reviewed)abstract
- The present study aimed to assess the efficacy of surgery and adjuvant therapy in older patients (age greater than= 70 years) with colorectal cancer (CRC). Older CRC patients are under-represented in available clinical trials, and therefore their outcomes after receiving surgery and adjuvant therapy are unclear. From two prospective Swedish databases, we assessed a cohort of 1021 patients who underwent curative surgery for stage I, II, or III primary CRC, with or without adjuvant chemotherapy/ radiotherapy. Of the patients with colon cancer (n = 467), 182 (39%) were aged less than70 years, 162 (35%) aged 70 to 80 years, and 123 (26%) were aged greater than= 80 years. Of rectal cancer patients (n = 554), 264 (48%) were aged less than70 years, 234 (42%) aged 70 to 80 years, and 56 (10%) aged greater than= 80 years. Older patients with either colon or rectal cancer had higher comorbidity than did younger patients. Older patients with colon cancer had equivalent postoperative morbidity and 30-day mortality to younger patients. Rectal cancer patients aged greater than= 80 years had a higher 30-day mortality than younger patients (odds ratio OR], 2.37; 95% confidence interval CI], 1.6-4.55; P = 0.03). For either colon or rectal cancer, adjuvant chemotherapy compromised the 5-year overall survival (OS) of older patients with stage II disease and had no effect on those with stage III disease. Receiving adjuvant chemotherapy was a poor factor of OS for older patients with either colon (HR 1.88, 95% CI: 1.20-4.35, P = 0.03) or rectal cancer (HR 1.72, 95% CI: 1.052.26, P = 0.004). Preoperative short-course radiotherapy improved both OS and local control for older patients with stage III rectal cancer and had no effect on those with stage II disease. Radiotherapy was a favorable factor for the OS of the older patients with rectal cancer (HR 0.42, 95% CI: 0.21-3.57, P = 0.01). In conclusion, Older CRC patients had equal safety of surgery as younger patients, except rectal cancer patients aged greater than= 80 years that had a higher mortality. Adjuvant 5FU-based chemotherapy did not benefit older CRC patient, while neoadjuvant radiotherapy improved the prognosis of older patients with stage III rectal cancer.
|
|
| 10. |
- Zhang, Dan, et al.
(author)
-
Polymorphisms of Glucose-Regulated Protein 78 and Risk of Colorectal Cancer : A Case-Control Study in Southwest China
- 2013
-
In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:6
-
Journal article (peer-reviewed)abstract
- Glucose-regulated protein 78 (GRP78), an endoplasmic reticulum chaperone, up-regulation serves as an efficient mechanism to promote malignant transformation of colorectal cancer (CRC) and protect CRC cells against apoptosis. Recently, the analysis of GRP78 polymorphisms has already determined that GRP78 rs391957 polymorphism could predict clinical outcome in CRC patients. Thus, we tested whether GRP78 polymorphisms are related to the risk of CRC. In this study, we detected two GRP78 polymorphisms (rs391957 (C>T) and rs430397 (G>A)) in 414 CRC cases and 502 hospital-based cancer-free healthy controls in Southwest China using a polymerase chain reaction–restriction fragment length polymorphism technique. Compared with the CC genotype, carriers of CT and TT genotypes of rs391957 polymorphism had higher risks of CRC (odds ratio (OR) = 1.39, 95% confidence interval (CI) = 1.06–1.83 for CT genotype and OR = 2.10, 95% CI = 1.06–4.14 for TT genotype, respectively). In CRC cases, the variant T allele was significantly associated with tumor invasion stage (P = 0.030), but not with status of lymph nodes metastasis (P = 0.052). Compared with the GG genotype, carriers of GA and AA genotypes of rs430397 polymorphism had higher risks of CRC (OR = 1.63, 95% CI = 1.23–2.15 for GA genotype and OR = 2.92, 95% CI = 1.23–6.94 for AA genotype, respectively). The rs430397 polymorphism was not associated with the clinicopathological characteristics of CRC. These data provide the first evidence that GRP78 rs391957 and rs430397 polymorphisms could serve as markers to predict the risk of CRC.
|
|
