Covalent organic frameworks (COFs), as a novel class of functional polymers, exhibit versatile applications due to their crystalline porous structures and conjugated skeletons. However, synthesis of ...COFs with high crystallinity still faces great challenges, especially for scale-up preparation. Herein we report a two-step solvothermal process to improve crystallinity of COFs. The first step focuses on polycondensation of monomers with no need for optimizing crystallization conditions. In the second step, appropriate solvothermal conditions are used to facilitate crystallization of the COFs through defects correction and structural repairing. Furthermore, this strategy could also be applicable to scale-up synthesis of high quality COFs, which lays a foundation for their practical applications.
A two-step solvothermal procedure is developed to synthesize covalent organic frameworks (COFs). This method not only affords COFs with high crystallinity, but also achieves scale-up synthesis. Display omitted
5-Methylcytosine (5-mC) is an important epigenetic mark that plays critical roles in a variety of cellular processes. To properly exert physiological functions, the distribution of 5-mC needs to be ...tightly controlled in both DNA and RNA. In addition to methyltransferase-mediated DNA and RNA methylation, premethylated nucleotides can be potentially incorporated into DNA and RNA during replication and transcription. To exclude the premodified nucleotides into DNA and RNA, endogenous 5-methyl-2′-deoxycytidine monophosphate (5-Me-dCMP) generated from nucleic acids metabolism can be enzymatically deaminated to thymidine monophosphate (TMP). Therefore, previous studies failed to detect 5-Me-dCMP or 5-methylcytidine monophosphate (5-Me-CMP) in cells. In the current study, we established a method by chemical labeling coupled with liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS/MS) for sensitive and simultaneous determination of 10 nucleotides, including 5-Me-dCMP and 5-Me-CMP. As N,N-dimethyl-p-phenylenediamine (DMPA) was utilized for labeling, the detection sensitivities of nucleotides increased by 88–372-fold due to the introduction of a tertiary amino group and a hydrophobic moiety from DMPA. Using this method, we found that endogenous 5-Me-dCMP and 5-Me-CMP widely existed in cultured human cells, human tissues, and human urinary samples. The presence of endogenous 5-Me-dCMP and 5-Me-CMP indicates that deaminases may not fully deaminate these methylated nucleotides. Consequently, the remaining premethylated nucleosides could be converted to nucleoside triphosphates as building blocks for DNA and RNA synthesis. Furthermore, we found that the contents of 5-Me-dCMP and 5-Me-CMP exhibited significant decreases in renal carcinoma tissues and urine samples of lymphoma patients compared to their controls, probably due to more reutilization of methylated nucleotides in DNA and RNA synthesis. This study is, to the best of our knowledge, the first report for detecting endogenous 5-Me-dCMP and 5-Me-CMP in mammals. The detectable endogenous methylated nucleotides indicate the potential deleterious effects of premodified nucleotides on aberrant gene regulation in cancers.
The uncontrollable migration of cancer cells is one of the reasons for the poor prognosis. The interaction between collagen and cellular processes is usually dominated by the full triple‐helix ...structure of collagen. However, it remains to be explored how the collagen configuration affects the migration behaviors of cancer cells. Michigan cancer foundation‐7 cells are chosen to study this relationship. Meanwhile, the grass carp is one of the representative fish species in Hubei and is virtually unaffected by zoonotic diseases. Therefore, grass carp‐derived collagen is prepared and used to modulate the migration behaviors. The collagen sample is pretreated via several procedures including the hydrothermal process and EDC/NHS, respectively. The underlying mechanisms affecting migration behavior are explored by tuning the degree of denaturation, assembly states, and cross‐linking conditions of collagen. Results demonstrate that moderate cross‐linking and assembly contribute to the migration processes, while denaturation significantly suppresses migration. Of particular note is the positive correlation of F‐actin expression levels with these phenomena. More importantly, the hydrophilic and hydrophobic properties of the collagen surface also affect the migration process. In summary, the study may provide insights to flexibly tune the migration behavior of cancer cells, which may be promising in inhibiting tumor metastasis.
The relationship between the configuration of grass crap‐derived collagen and migration behavior of cancerous cells is studied in this article. Results confirm that denaturation inhibits migration, while cross‐linking and assembly contribute to the migration of michigan cancer foundation‐7 cells. This study may provide an opportunity for exploring the utilization value of collagen‐based biomaterials for inhibiting tumor metastasis.
Some modified ribonucleosides in biological fluids have been evaluated as cancer-related metabolites. Detection of endogenous modified ribonucleosides in biological fluids may serve as a noninvasive ...cancers diagnostic method. However, determination of modified ribonucleosides is still challenging because of their low abundance and serious matrix interferences in biological fluids. Here, we developed a novel strategy for comprehensive profiling of ribose conjugates from biological fluids using metal oxide-based dispersive solid-phase extraction (DSPE) followed with in vitro stable isotope labeling and double neutral loss scan-mass spectrometry analysis (DSPE-SIL-LC-DNLS-MS). Cerium dioxide (CeO2) was used to selectively recognize and capture ribose conjugates from complex biological samples under basic environment. The enriched ribose conjugates were subsequently labeled with a pair of isotope labeling reagents (acetone and acetone-d6). The glucosidic bond of acetone labeled ribose conjugates is readily ruptured, and the generated ribose that carries an isotope tag can be lost as a neutral fragment under collision induced dissociation (CID). Since the light (acetone) and heavy (acetone-d6) labeled compounds have the same chemical structures and can generate different neutral loss fragments (NL 172 and 178 Da), it is therefore highly convenient to profile ribose conjugates by double neutral loss scan mode in mass spectrometry analysis. In this respect, the light and heavy labeled compounds were ionized at the same condition but recorded separately on MS spectra, which can significantly improve the detection specificity and facilitate the identification of ribose conjugates. Using the developed DSPE-SIL-LC-DNLS-MS strategy, we profiled the ribose conjugates in human urine, and 49 ribose conjugates were readily identified, among which 7 ribose conjugates exhibited significant contents change between healthy controls and lymphoma patients. The DSPE-SIL-LC-DNLS-MS strategy combines the selective enrichment, stable isotope labeling, and double neutral loss scan - MS analysis, which therefore can efficiently minimize false positive results, facilitate the relative quantification, and notably increase the numbers of identified ribose conjugates in biological fluids samples. Taken together, this study established a promising strategy for the effective profiling of urinary modified ribonucleosides, and simultaneous evaluation of the contents change of multiple modified ribonucleosides should provide more accurate and conclusive results for the use of urinary modified ribonucleosides as indicators of cancers.
RNA contains a large number of modified nucleosides. In the metabolic re-exchange of RNA, modified nucleosides cannot be recycled and are thus excreted from cells into biological fluids. ...Determination of endogenous modified nucleosides in biological fluids may serve as non-invasive cancers diagnostic methods. Here we prepared boronate-affinity organic-silica hybrid capillary monolithic column (BOHCMC) that exhibited excellent selectivity toward the cis-diol-containing compounds. We then used the prepared BOHCMC as the on-line solid-phase microextraction (SPME) column and developed an on-line SPME-LC-MS/MS method to comprehensively profile cis-diol-containing nucleosides and ribosylated metabolites in human urine. Forty-five cis-diol-containing nucleosides and ribosylated metabolites were successfully identified in human urine. And five ribose conjugates, for the first time, were identified existence in human urine in the current study. Furthermore, the relative quantification suggested 4 cis-diol-containing compounds (5'-deoxy-5'-methylthioadensine, N(4)-acetylcytidine, 1-ribosyl-N-propionylhistamine and N(2),N(2),7-trimethylguanosine) increased more than 1.5 folds in all the 3 types of examined cancers (lung cancer, colorectal cancer, and nasopharyngeal cancer) compared to healthy controls. The on-line SPME-LC-MS/MS method demonstrates a promising method for the comprehensive profiling of cis-diol-containing ribose conjugates in human urines, which provides an efficient strategy for the identification and discovery of biomarkers and may be used for the screening of cancers.
The purpose of the study was to evaluate the efficiency of the supine roll test(SRT)and alternative positional tests(APTs)including the bow and lean test(BLT),pseudo-spontaneous nystagmus(PSN),and ...lying down nystagmus(LDN)to identify the affected side in horizontal canal benign paroxysmal positional vertigo(HC-BPPV).Methods:In our prospective study,we performed a testing profile(PSN,BLT,LDN,SRT)on 59 HC-BPPV patients using videonystagmography.We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization.Data from 30 healthy patients were collected as the control group.Results:When performing positional tests,the elicited nystagmus coinciding with Ewald's second law was defined as a"positive response".In 44 patients with geotropic nystagmus,the rates of positive response in LDN,PSN,and BLT were 22/44(50％),19/44(43％),and 18/44(41％),respectively,while in 15 patients with apogeotropic nystagmus,the positive response rates of these three tests were 10/15(66.7％),9/15(60％),and 4/15(27.00％),respectively.The sensitivity of LDN(54.38％)was higher than that of PSN(47.37％)and BLT(38.60％)but lower than that of SRT(89.47％).Notably,the accuracy rate of PSN(71.8％)was higher than that of the other APTs.In 6 patients with symmetrical nysgtamus during the roll test,5 patients showed a positive response in both LDN and BLT(83.34％),whereas 4 patients showed a positive response in PSN(66.67％).Conclusion:All positional tests are helpful for determining the affected side of HC-BPPV,but SRT carries the highest accuracy of lateralization followed by PSN.
Myofibroblasts, the primary effector cells for implant-induced fibrosis, contribute to this process by secreting excessive collagen-rich matrix and contracting. Thus, approaches that suppress ...myofibroblasts may achieve desirable suppression effects in the fibrotic process. As one of the important physical properties of materials, material topographical structures have been proven to affect various aspects of cell behaviors, so is it possible to manipulate the formation of myofibroblasts by tailoring the topographical properties of medical devices? In this study, polycaprolactone (PCL) surfaces with typical micropatterns (micro column and micro pit) were fabricated. The regulatory effects of surface micropatterns on the myofibroblastic differentiation of fibroblasts were investigated. Compared to the flat surfaces and surfaces with micro pit, surfaces with micro columns triggered the F- to G-actin transition, inhibiting the nuclear transfer of myocardin-related transcription factor-A. Subsequently, the downstream gene α-smooth muscle actin, which is a marker of myofibroblasts, was suppressed. Further in vivo investigation showed that PCL implants with micro-column-patterned surfaces inhibited the formation of peri-implant fibrotic capsules. Our results demonstrate that surface topographical properties are a potent regulator of fibroblast differentiation into myofibroblasts and highlight the antifibrotic potential of modifying surfaces with micro-column patterns.
Age-related hearing loss (AHL), characterized by degeneration of cochlea structures, is the most common sensory disorder among the elderly worldwide. The calcium channel is considered to contribute ...to normal hearing. However, the role of the T-type voltage-activated calcium channel, Cav3.1, remains unclear in AHL. Here, we investigate the age-related change of Cav3.1 expression in the cochlea and D-gal-induced senescent HEI-OC1 cells.
Cochleae from C57BL/6 mice at 2 months and 12 months of age were assessed. Senescence in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells was induced by D-gal treatment. The immunofluorescence technique was employed to investigate the distribution of Cav3.1 in vivo and in vitro. Quantitative assessment was achieved by Western blotting and real-time PCR.
In comparison with 2-month-old animals, 12-month old C57BL/6 mice exhibited great loss of hair cells and elevated auditory brainstem threshold. The Cav3.1 was located in hair cells, spiral ganglion cells, lateral walls, and the expression of Cav3.1 protein and mRNA decreased in the aged cochleae. D-gal-induced senescence assay confirmed the down-regulation of Cav3.1 expression in senescent HEI-OC1 cells.
Our results show that age-related down-regulated expression of Cav3.1 in the cochleae is associated with AHL and may contribute to the pathogenesis of AHL.
K+cycling in the cochlea is critical to maintain hearing.Many sodium-potassium pumps are proved to participate in K+cycling,such as Na/K-ATPase.The α2-Na/K-ATPase is an important isoform of ...Na/K-ATPase.The expression of α2-Na/K-ATPase in the cochlea is not clear.In this study,we used C57BL/6 mice as a model of presbycusis and implemented immunohistochemistry staining and quantitative real time-PCR,and the α2-Na/K-ATPase expression pattern was confirmed in the inner ear.It was found α2-Na/K-ATPase was expressed widely in cochlea and its mRNA and protein expression was gradually reduced with aging(4-,14-,26-and 48-weeks old mice).We suspected that,the down-regulation of α2-Na/K-ATPase expression might be associated with the remodeling of K+cycling,degeneration of morphological structure and decrease of hearing function in aging C57 mice.In conclusion,we speculated that the reduction of α2-Na/K-ATPase might play an important role in the pathogenesis of age-related hearing loss.
In order to promote the application of aeolian sand in concrete frame structures, it is necessary to study the seismic damage performance of aeolian sand concrete columns. In this paper, 4 concrete ...column specimens with different replacement percentages of aeolian sand were tested under lateral cyclic loading. The 4 replacement percentages of aeolian sand were 0%, 10%, 20%, and 30%. The seismic damage process of the specimens was studied by comparing the seismic indexes exhibited in the test. Then, the damage model of the specimens was studied. The results showed that the specimen whose replacement percentage of aeolian sand reached 30% had superior seismic damage performance. Its degree of damage was smaller than that of the other specimens under the same conditions. Its seismic indexes, including the bearing capacity, ductility, stiffness degradation, and energy dissipation capacity, performed much better than those of the other specimens. Besides, this paper proposes a damage model of an aeolian sand concrete column based on current results. This model can be used to evaluate the damage degree of this kind of column.
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