The physicochemical properties and application performances of graphitic carbon nitride (g‐CN) are highly dependent on its polymerization degree, thus a facile method for screening the polymerization ...degree is highly desired. Here, electrochemiluminescence (ECL) is creatively employed as an effective tool to achieve this goal. Extension of π‐system and change in pedant groups during g‐CN polymerization process are characterized by g‐CN nanosheets/dissolved oxygen (CNNS/O2) and Ru(bpy)32+/CNNS co‐reactant ECL systems, respectively. Linear intensity enhancement along with positive shift in the onset and peak potentials of cathodic CNNS/O2 ECL, as well as linear intensity decreasing in anodic Ru(bpy)32+/CNNS ECL, are observed during polymerization of dicyandiamide to g‐CN, suggesting the feasibility of ECL on studying the polymerization degree. The ECL method would provide a promising prospect for novel properties exploration and application performances optimization of g‐CN.
Electrochemiluminescence is used to characterize the extension of π‐system and change in pedant groups during graphitic carbon nitride (g‐CN) polymerization process by using g‐CN nanosheets (CNNS)/O2 and Ru(bpy)32+/CNNS co‐reactant ECL systems.
Two-dimensional graphite-like carbon nitride nanosheets (g-... NSs) were hybridized with gold nanoparticles (Au NPs) to construct an electrochemiluminescence (ECL) immunosensor. The prepared Au ...NP-functionalized g-... NS nanohybrids (Au-g-... NHs) exhibit strong and stable cathodic ECL activity compared to g-... NSs due to the important roles of Au NPs in trapping and storing the electrons from the conduction band of g-... NSs, as well as preventing high energy electron-induced passivation of g-... NSs. On the basis of the improved ECL stability and ECL peak intensity of the Au-g-... NHs, a novel ECL immunosensor was developed to detect carcinoembryonic antigen (CEA) as a model target analyte. The ECL immunosensor has a sensitive response to CEA in a linear range of 0.02-80 ng mL... with a detection limit of 6.8 pg mL... Additionally, the proposed immunosensor shows high specificity, good reproducibility, and long-term stability. (ProQuest: ... denotes formulae/symbols omitted.)
Two-dimensional graphite-like carbon nitride nanosheets (g-... NSs) were hybridized with gold nanoparticles (Au NPs) to construct an electrochemiluminescence (ECL) immunosensor. The prepared Au ...NP-functionalized g-... NS nanohybrids (Au-g-... NHs) exhibit strong and stable cathodic ECL activity compared to g-... NSs due to the important roles of Au NPs in trapping and storing the electrons from the conduction band of g-... NSs, as well as preventing high energy electron-induced passivation of g-... NSs. On the basis of the improved ECL stability and ECL peak intensity of the Au-g-... NHs, a novel ECL immunosensor was developed to detect carcinoembryonic antigen (CEA) as a model target analyte. The ECL immunosensor has a sensitive response to CEA in a linear range of 0.02-80 ng mL... with a detection limit of 6.8 pg mL... Additionally, the proposed immunosensor shows high specificity, good reproducibility, and long-term stability. (ProQuest: ... denotes formulae/symbols omitted.)
Some cancers can be cured by chemotherapy or radiotherapy, presumably because they are derived from those cell types that not only can die easily but also have already been equipped with mobility and ...adaptability, which would later allow the cancers to metastasize without the acquisition of additional mutations. From a viewpoint of biological dispersal, invasive and metastatic cells may, among other possibilities, have been initial losers in the competition for resources with other cancer cells in the same primary tumor and thus have had to look for new habitats in order to survive. If this is really the case, manipulation of their ecosystems, such as by slightly ameliorating their hardship, may prevent metastasis. Since new mutations may occur, especially during and after therapy, to drive progression of cancer cells to metastasis and therapy-resistance, preventing new mutations from occurring should be a key principle for the development of new anticancer drugs. Such new drugs should be able to kill cancer cells very quickly without leaving the surviving cells enough time to develop new mutations and select resistant or metastatic clones. This principle questions the traditional use and the future development of genotoxic drugs for cancer therapy.
The search for a biocompatible co‐reactant for tris(2,2′‐bipyridine)ruthenium(II) (Ru(bpy)32+) electrochemiluminescence (ECL) has attracted broad attention towards extending its application in the ...biomedical field. This work investigates the co‐reactant effect of graphitic carbon nitride nanosheets (CNNSs) on Ru(bpy)32+ ECL. CNNSs enhance the anodic ECL of Ru(bpy)32+ through the ECL interaction between Ru(bpy)33+ and the reductive intermediate of CNNSs, which are generated by either the direct electroreduction of CNNSs or the chemical/electrochemical oxidation of the amine groups on the CNNSs surface by Ru(bpy)33+. The finding may provide a new avenue for the development of self‐enhanced ECL probes and offer a new insight into revealing the surface feature of CNNSs.
Helping hand: Graphitic carbon nitride nanosheets act as a co‐reactant to enhance the anodic electrochemiluminescence of Ru(bpy)32+.
We introduce a convenient single-step approach for controlled synthesis of unique two- and three-dimensional hierarchical assemblies of silver nanoparticles by utilizing binary and ternary mixtures ...of capping agents. The binary mixtures comprise of trisodium citrate mixed with either cysteamine or mercaptopropionic acid while the ternary mixtures feature the addition of glucose. We observed the gradual evolution of silver nanoparticle assemblies from a closed-packed arrangement to a flower-like superstructure by simply adjusting the amount of trisodium citrate relative to a fixed amount of cysteamine. The addition of glucose to this binary mixture drastically changes the growth mechanism and instead resulted in nanodisc stacks; this is the first observation of such hierarchical silver nanodisc stacks. On the other hand, the addition of glucose to the binary mixture of mercaptopropionic acid and trisodium citrate produced belt-shaped ensembles with adjustable length. Interestingly, with increasing length, a secondary assembly of silver nanoparticles into petal-shaped structures occurred on the belt surface. While we show that all the structures we prepared can amplify surface enhanced Raman scattering signals, primarily due to their rough morphology, we believe our method can also be extended to other applications, since it provides a simple means to obtain both tuneable and drastically different predefined silver nanoensembles.
There are four basic cell death modes in animals, i.e. physiological senescent death (SD) and apoptosis as well as pathological necrosis and stress-induced cell death (SICD). There have been numerous ...publications describing "apoptosis" in cancer, mostly focused on killing cancer cells using radio- or chemo-therapy, with few on exploring how cancer cells die naturally without such treatments. Spontaneous benign or malignant neoplasms are immortal and autonomous, but they still retain some allegiance to their parental tissue or organ and thus are still somewhat controlled by the patient's body. Because of these properties of immortality, semi-autonomy, and semi-allegiance to the patient's body, spontaneous tumors have no redundant cells and resemble "semi-new organisms" parasitizing the patients, becoming a unique tissue type possessing a hitherto unannotated cell death mode besides SD, apoptosis, necrosis and SICD. Particularly, apoptosis aims to expunge redundant cells, whereas this new mode does not. In contrast to spontaneous tumors, many histologically malignant tumors induced in experimental animals, before they reach an advanced stage, regress after withdrawal of the inducer. This mortal and non-autonomous nature disqualifies these animal lesions as authentic neoplasms and as semi-new organisms but makes them a good tissue type for apoptosis studies. Ruminating over cell death in spontaneous cancers and many inauthentic tumors induced in animals from these new slants makes us realize that "whether cancer cells undergo apoptosis" is not an easy question with a simple answer. Our answer is that cancer cells have an uncharacterized programmed cell death mode, which is not apoptosis.
"Gene amplification causes overexpression" is a longstanding and well-accepted concept in cancer genetics. However, raking the whole literature, we find only statistical analyses showing a positive ...correlation between gene copy number and expression level, but do not find convincing experimental corroboration for this notion, for most of the amplified oncogenes in cancers. Since an association does not need to be an actual causal relation, in our opinion, this widespread notion still remains a reasonable but unproven assumption awaiting experimental verification.
The prevalence of infection by different genotypes of human papillomavirus (HPV) varies among different geographic areas. We studied the prevalence of infection by 21 HPV genotypes in cervical tissue ...specimens from 4213 women in the Guiyang district, that is located in the southwest of China and is dominated by minor ethnicities of Chinese, and 2074 cases in our cohort had pathological diagnosis available. The overall infection rate was 36.98%. Most (72.08%) infectors were positive for only one HPV subtype, with the remaining being cases infected by two or more subtypes. Infections by the HPV subtypes 16, 52 and 58 were the most prevalent, having rates of 34.66%, 16.03%% and 15.53%, respectively. The most common cervical lesions in HPV infections were genital warts, cervical cancer (CC) and cervical intraepithelial neoplasia (CIN). Age and age at first sexual activity were independent risk factors for HPV infections that in turn cause certain cervical lesions. Intriguingly, while 94.90% of the CC patients were infected by oncogenically high-risk (HR) HPV subtypes, only 2.75% and 2.29% of these patients were infected by oncogenically low-risk (LR) subtypes or other-subtypes with their oncogenicity unclear. The rates of infection by LR-HPVs and other-HPVs were also low, being 4.63% and 6.76%, respectively, in the patients with CIN that is a precursor lesion of CC, lower than the 8.54% and 18.20%, respectively, in the women without a cervical lesion. Our data provides an important foundation for prevention, diagnosis and treatment of HPV infection in Guiyang district and suggests that development of vaccines for prevention and treatment of CC in this area should first target the HPV subtypes 16, 52 and 58, but not subtype 18 as for many other places. It deserves study whether infections by certain LR-HPVs and other-HPVs may serve as attenuated live vaccines for prevention of CC.
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