External root resorption (ERR) is a silent destructive phenomenon detrimental to dental health. ERR may have multiple etiologies such as infection, inflammation, traumatic injuries, pressure, mechanical stimulations, neoplastic conditions, systemic disorders, or idiopathic causes. Often, if undiagnosed and untreated, ERR can lead to the loss of the tooth or multiple teeth. Traditionally, clinicians have relied on radiographs and cone beam computed tomography (CBCT) images for the diagnosis of ERR; however, these techniques are not often precise or definitive and may require exposure of patients to more ionizing radiation than necessary. To overcome these shortcomings, there is an immense need to develop non-invasive approaches such as biomarker screening methods for rapid and precise diagnosis for ERR. In this review, we performed a literature survey for potential salivary or gingival crevicular fluid (GCF) proteomic biomarkers associated with ERR and analyzed the potential pathways leading to ERR. To the best of our knowledge, this is the first proteomics biomarker survey that connects ERR to body biofluids which represents a novel approach to diagnose and even monitor treatment progress for ERR. 相似文献
There is growing interest in the use of structure-based virtual screening to identify small molecules that inhibit challenging protein–protein interactions (PPIs). In this study, we investigated how effectively chemical library members docked at the PPI interface mimic the position of critical side-chain residues known as “hot spots”. Three compound collections were considered, a commercially available screening collection (ChemDiv), a collection of diversity-oriented synthesis (DOS) compounds that contains natural-product-like small molecules, and a library constructed using established reactions (the “screenable chemical universe based on intuitive data organization”, SCUBIDOO). Three different tight PPIs for which hot-spot residues have been identified were selected for analysis: uPAR⋅uPA, TEAD4⋅Yap1, and CaVα⋅CaVβ. Analysis of library physicochemical properties was followed by docking to the PPI receptors. A pharmacophore method was used to measure overlap between small-molecule substituents and hot-spot side chains. Fragment-like conformationally restricted small molecules showed better hot-spot overlap for interfaces with well-defined pockets such as uPAR⋅uPA, whereas better overlap was observed for more complex DOS compounds in interfaces lacking a well-defined binding site such as TEAD4⋅Yap1. Virtual screening of conformationally restricted compounds targeting uPAR⋅uPA and TEAD4⋅Yap1 followed by experimental validation reinforce these findings, as the best hits were fragment-like and had few rotatable bonds for the former, while no hits were identified for the latter. Overall, such studies provide a framework for understanding PPIs in the context of additional chemical matter and new PPI definitions. 相似文献
We introduce a new learning problem: learning a graph bypiecemeal search, in which the learner must return every so often to its starting point (for refueling, say). We present two linear-time piecemeal-search algorithms for learningcity-block graphs: grid graphs with rectangular obstacles. 相似文献
Heterogeneous photocatalysed reduction of aqueous Na2CO3 solution (1 m) was achieved by using phthalocyanine-coated semiconductor powders (1–3% coating) as well as bare semiconductors. The suspensions were irradiated with 254 nm light from a low-pressure mercury lamp in a nitrogen atmosphere. The phthalocyanine dyes (Fe2+-Pc or Co2+-Pc) absorb > 80% of the 254 nm radiation and thus sensitize the semiconductor. The products of reduction (CH3OH and HCHO) were determined spectrophotometrically. The CH3OH yields obtained are much higher than the HCHO yields, due to a photocatalysed reduction of HCHO to CH3OH. The CH3OH yields from coated titania increased linearly with irradiation time over the period 6–18 h. However, the straight line does not pass through the origin, and it seems that a slowing-down occurs at times > 6 h. Titania coated with both dyes gave an optimum CH3OH yield at 2% surface coating. At higher coating percentages, phthalocyanine screens the surface, thus reducing the light reaching the semiconductor. Changing the redox potential of the phthalocyanine dye by changing its central metal from Fe to Co affects the CH3OH yields. The bare MoS2 photocatalyst gave a much higher CH3OH yield due to the characteristic behaviour of the semiconducting layer-type disulphide, distinguished from that of classical semiconducting materials. In the various semiconductors studied, it seems that there is no correlation between the position of the conduction band and the yield of CH3OH. Such correlation was argued. Generally, a decrease in the yield of CH3OH was observed as the band gap width of the semiconductor increased. The yields of the photoproduced CH3OH generally increased with the percentage of light absorbed at 254 nm by the various semiconductors. Irradiation leads to the production of electrons in the conduction band of the semiconductor. It is likely that the photoproduced electrons reduce CO32- initially to HCOO- and then to HCHO and CH3OH. 相似文献
This study replicated and extended a study of Cummings (1987) by examining 4- and 5-year-olds' behavioral and verbal responses to adults' angry behavior and collected data on physiological responses. We found behavioral and verbal responses of distress and that systolic blood pressure increased in response to anger. As in Cummings (1987), children's behavioral emotional responses to anger predicted other aspects of responding. Angry/ambivalent children showed a complex heart rate pattern, including a decrease with the onset of anger, whereas heart rate increased in response to anger for concerned/distressed children. Both groups reported more emotional distress (mostly anger) than unresponsive children, and angry–ambivalent children reported the most nonplay responses (e.g., leave, mediate). The results provide more support for discrete patterns of responding to adults' angry emotions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
In the current study, chitosan was extracted by deacetylation of chitin, which is extracted from shrimp shell. chitosan nanoparticles (CSNPs) were prepared by ionotropic gelation technique. chitosan/tripolyphosphate ratio (CS:TPP) was kept at 3:1 to prepare CSNPs. chitosan/silver nanocomposite (CS/AgNCs) were prepared by incorporating silver nanoparticles into CSNPs. The quality of the prepared nanocomposite was evaluated by infrared spectroscopy, UV–Vis spectroscopy, transmission electron microscopy, and antibacterial activity. Results showed that chitosan/silver nanocomposite in which, both chitosan and silver are in nanoscale was successfully prepared for the first time in a well-dispersed aqueous form. Whereas CSNPs act as a host material to form the nanocomposite unlike the previously prepared forms of chitosan–silver nanocomposites, that used chitosan bulk as host materials and the dispersion medium was slightly acidic. Moreover, results revealed that the antibacterial activity of CSNPs was significantly enhanced after incorporating trace amount of silver nanoparticles (0.535% w/w AgNPs/CSNPs). 相似文献
In this work, a variety of photoactive linear and hyperbranched unsaturated polyesters P1a-d, P2a-d and P3a-d, were successfully synthesized via ring-opening polymerization of diarylidene epoxy monomers 2a-d with terephthalic acid, isophthalic acid or trimesic acid in presence of TABI as a catalyst. First, diarylidene-epoxy monomers 2a-d were obtained from diols of diarylidene cycloalkanones derivatives 1a-d followed by epoxidation with epichlorohydrin in presence of NaOH and TBAI. These diaryldene epoxy monomers 2a-d were applied in the preparation of P1a-d, P2a-d and P3a-d. The molar masses of the resulting unsaturated polyesters were determined by gel permeation chromatography (GPC); all polymers have moderate molar masses. The photo-responsive properties of selected examples of polymers were tested in THF under UV lamp (450 nm) at different time intervals, This study revealed the occurrence of photocrosslinking behavior in the system under these conditions. The thermal properties of these polyesters were evaluated by thermogravimetric analysis (TGA). The morphological properties of selected examples of polymers were tested using scanning electron microscope (SEM). In addition, the cytotoxicity of the prepared monomers and selected polymers was tested against HeLa cervical cancer cells using MTT cell viability assay. All monomers except 2c showed significant cytotoxic effects with IC50?>?21 μM. In contrast, the tested polymers were less potent against HeLa cells.
Wireless Personal Communications - Existing security approaches for safeguarding data exchange among the sensor nodes are investigated in presence of apriori information of an adversary in... 相似文献