Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between ...them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 x 10⁻¹⁶ fractional level, surpassing the current best evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation-induced frequency shifts.
Tumor necrosis factor-α stimulates fractalkine production by mesangial cells and regulates monocyte transmigration: Down-regulation by cAMP.
Fractalkine is a CX3C chemokine for mononuclear cells that ...has been implicated in the recruitment and accumulation of monocytes seen in glomerular diseases. We investigated the mechanisms by which tumor necrosis factor (TNF)-α stimulates mesangial cell (MC) fractalkine expression, and the effects of MC-derived fractalkine on monocyte transmigration.
Cultured rat MCs were incubated with TNF-α, with or without pretreatment with pharmacologic inhibitors of protein kinases or transcriptional factors downstream to TNF-α. Fractalkine mRNA and protein were analyzed by Northern and Western blotting. Translocation of nuclear factor (NF)-κB was evaluated by immunocytochemical staining. Monocyte transmigration was determined by in vitro chemotaxis assay.
TNF-α stimulated MC fractalkine mRNA as well as cell-bound and soluble protein expression in a dose- and time-dependent manner. The soluble fractalkine was shed from the cell-bound form via metalloproteinase-dependent cleavage, and mediated in part TNF-α–induced monocyte transmigration in vitro. The incubation of MCs with calphostin C a selective inhibitor of protein kinase C (PKC) or PD98059 a selective inhibitor of p42/44 mitogen-activated protein kinase (MAPK) kinase attenuated TNF-α–stimulated fractalkine mRNA and protein expression. Coincubation of MCs with calphostin C and PD98059 resulted in a synergistic inhibition of TNF-α–stimulated fractalkine mRNA and protein expression. Incubation of MCs with phorbol myristate acetate (PMA) for four hours resulted in an increase in fractalkine mRNA expression that could be suppressed by calphostin C or depletion of PKC by pretreatment with PMA for 24 hours. Further, activation of PKC-depleted MCs with TNF-α stimulated fractalkine mRNA expression that could be blocked by calphostin C. PD 98059, but not calphostin C, inhibited TNF-α–activated phospho-p42/44 MAPK and phospho-c-Jun levels, whereas only calphostin C inhibited TNF-α–activated phosphorylation of PKCζ/ι. The incubation of MCs with MG132, a NF-κB inhibitor, abolished TNF-α–induced degradation of inhibitory protein of NF-κB (I-κB)α, nuclear translocation of NF-κB, and fractalkine expression, without affecting phospho-c-Jun levels. In contrast, curcumin, an activating protein (AP)-1 inhibitor, attenuated TNF-α–stimulated phospho-c-Jun levels and fractalkine expression without discernible effects on TNF-α–induced degradation of I-κBα or NF-κB nuclear translocation. Neither PD 98059 nor calphostin C affected TNF-α–induced degradation of I-κBα or NF-κB nuclear translocation. Additional experiments examining the role of cAMP on MC fractalkine expression showed that the incubation of MCs with TNF-α and either db-cAMP or forskolin attenuated TNF-α–stimulated fractalkine mRNA and protein expression, preceded by attenuation of TNF-α–activated phosphorylation of p42/44 MAPK, and c-Jun, but not phosphorylation of PKCζ/ι or nuclear translocation of NF-κB.
The present data indicate that TNF-α activation of PKCζ/ι, p42/44 MAPK, c-Jun/AP-1, and p65/NF-κB are involved in TNF-α–stimulated MC fractalkine expression, with the soluble fractalkine mediating in part the TNF-α–induced monocyte transmigration in vitro. Uncoupling of p42/44 MAPK or c-Jun/AP-1 signals may contribute to cAMP inhibition of MC fractalkine expression activated by TNF-α.
A novel and effective method has been developed for chiral discrimination using a quartz crystal microbalance (QCM) biosensor with self-assembled bovine serum albumin (BSA) or human serum albumin ...(HSA). The successfully constructed QCM chiral biosensors exhibited rapid and real-time enantioselective recognition. The QCM chiral discrimination factor (αQCM) can be calculated through resonance frequency shifts in response to five pairs of enantiomers. Moreover, the interactions between these ten enantiomers and two serum albumins (SA) were investigated in detail by means of ultraviolet–visible (UV–vis) and fluorescence (FL) spectra. The results indicated that the discrimination ability were quite different between BSA and HSA. R,S-1-(3-Methoxyphenyl)ethylamine (R,S-3-MPEA) and R,S-1-(4-methoxyphenyl)ethylamine (R,S-4-MPEA) can be easily differentiated by the BSA sensor, while the selectivity of the HSA sensor for R,S-tetrahydronaphthylamine (R,S-TNA), R,S-2-octanol (R,S-2-OT) and R,S-methyl lactate (R,S-MEL) was higher than that of the BSA sensor. The UV and FL spectra indicated the formation of a complex between SA and enantiomers and strong fluorescence quenching through static quenching mechanism. The in-depth study demonstrated that the calculated UV/FL discrimination factors (αUV and αFL) were consistent with the QCM experimental results (αQCM).
Peripheral nerve injury is a common trauma, but presents a significant challenge to the clinic. Silk-based materials have recently become an important biomaterial for tissue engineering applications ...due to silk's biocompatibility and impressive mechanical and degradative properties. In the present study, a silk fibroin peptide (SF16) was designed and used as a component of the hydrogel scaffold for the repair of peripheral nerve injury.
The SF16 peptide's structure was characterized using spectrophotometry and atomic force microscopy, and the SF16 hydrogel was analyzed using scanning electron microscopy. The effects of the SF16 hydrogel on the viability and growth of live cells was first assessed in vitro, on PC12 cells. The in vivo test model involved the repair of a nerve gap with tubular nerve guides, through which it was possible to identify if the SF16 hydrogel would have the potential to enhance nerve regeneration. In this model physiological saline was set as the negative control, and collagen as the positive control. Walking track analysis and electrophysiological methods were used to evaluate the functional recovery of the nerve at 4 and 8 weeks after surgery.
Analysis of the SF16 peptide's characteristics indicated that it consisted of a well-defined secondary structure and exhibited self-assembly. Results of scanning electron microscopy showed that the peptide based hydrogel may represent a porous scaffold that is viable for repair of peripheral nerve injury. Analysis of cell culture also supported that the hydrogel was an effective matrix to maintain the viability, morphology and proliferation of PC12 cells. Electrophysiology demonstrated that the use of the hydrogel scaffold (SF16 or collagen) resulted in a significant improvement in amplitude recovery in the in vivo model compared to physiological saline. Moreover, nerve cells in the SF16 hydrogel group displayed greater axon density, larger average axon diameter and thicker myelin compared to those of the group that received physiological saline.
The SF16 hydrogel scaffold may promote excellent axonal regeneration and functional recovery after peripheral nerve injury, and the SF16 peptide may be a candidate for nerve tissue engineering applications.
Helicobacter pylori infection is a major cause of gastritis and may be a key risk factor for stomach cancer, but its role in the process of gastric carcinogenesis is not well understood. Herein, we ...examine H. pylori prevalence in relation to demographic and lifestyle factors and to severity of precancerous lesions in an area of China with one of the highest rates of stomach cancer in the world. H. pylori serum IgG antibody positivity was assayed among 2646 adults, ages 35-64, participating in a population-based gastroscopic screening survey in the high-risk area. The prevalence of positivity was evaluated according to gastric histology, environmental and lifestyle variables determined by interviews during the screening, and level of serum pepsinogens. The odds of advanced precancerous lesions (intestinal metaplasia and dysplasia) of the stomach among those with antibody positivity were estimated by logistic regression. Seventy-two % of the population was H. pylori antibody-positive, with nonsignificant variation by sex, age, income, education, family size, and cigarette smoking habits. H. pylori positivity was higher among those who ate sour pancakes, a fermented indigenous staple that is a risk factor for gastric dysplasia and stomach cancer in this population. The prevalence of H. pylori varied most notably, however, with gastric pathology. The percent of H. pylori positivity increased from 55 to 60 to 87% among those with superficial (nonatrophic) gastritis, mild chronic atrophic gastritis, and severe chronic atrophic gastritis, respectively, before falling to 78% among those with intestinal metaplasia or dysplasia. H. pylori antibody positivity also was strongly correlated with serum pepsinogen concentrations, particularly pepsinogen II, but knowledge of H. pylori status did not markedly improve serological identification of advanced precancerous lesions above that provided by pepsinogen ratios alone. The findings suggest that H. pylori infection contributes to the process of gastric carcinogenesis, particularly during the early stages, in this high-risk area.
The elevation of cellular retinoic acid-binding protein-I (CRABP-I) has been suggested as a candidate in the pathogenesis of paediatric moyamoya disease (MMD). However, few studies have addressed ...CRABP-I in adult onset MMD. The aim of this study was to examine the expression of CRABP-I in the cerebrospinal fluid (CSF) of adult onset MMD, and to evaluate its association with clinical presentation and postoperative haemodynamic change.
This study examined the CSF from 103 patients: bilateral MMD, n=58 (56.3%); unilateral MMD, n=19 (18.4%); atherosclerotic cerebrovascular disease (ACVD), n=21 (20.4%); and control group, n=5 (4.9%). The intensity of CRABP-I was confirmed by western blotting and expressed as the median (25th-75th percentile). The differences in CRABP-I expression according to disease entity (unilateral MMD vs bilateral MMD vs ACVD), initial presenting symptoms (haemorrhage vs ischaemia) and postoperative haemodynamic change (vascular reserve in single photon emission CT and basal collateral vessels in digital subtraction angiography) were analysed.
CRABP-I intensities in bilateral MMD (1.45(0.86-2.52)) were significantly higher than in unilateral MMD (0.91(0.78-1.20)) (p=0.044) or ACVD (0.85(0.66-1.11)) (p=0.004). No significant differences were noted based on the initial presenting symptoms (p=0.687). CRABP-I was not associated with improvement in vascular reserve (p=0.327), but with decrease in basal collateral vessels (p=0.023) postoperatively.
Higher CRABP-I in the CSF can be associated with typical bilateral MMD pathogenesis in adults. Additionally, postoperative basal collateral change may be related to the degree of CRABP-I expression.
Hydrothermally stable and structrurally ordered mesoporous and microporous aluminosilicates with different pore sizes have been synthesized to immobilize cytochrome c (cyt c): MAS-9 (pore size 90 ...Å), MCM-48-S (27 Å), MCM-41-S (25 Å), and Y zeolites (7.4 Å). The amount of cyt c adsorption could be increased by the introduction of aluminum into the framework of pure silica materials. Among these mesoprous silicas (MPS), MAS-9 showed the highest loading capacity due to its large pore size. However, cyt c immobilized in MAS-9 could undergo facile unfolding during hydrothermal treatments. MCM-41-S and MCM-48-S have the pore sizes that match well the size of cyt c (25 × 25 × 37 Å). Hence the adsorbed cyt c in these two medium pore size MPS have the highest hydrothermal stability and overall catalytic activity. On the other hand, the pore size of NaY zeolite is so small that cyt c is mostly adsorbed only on the outer surface and loses its enzymatic activity rapidly. The improved stability and high catalytic activity of cyt c immobilized in MPS are attributed to the electrostatic attraction between the pore surface and cyt c and the confinement provided by nanochannels. We further observed that cyt c immobilized in MPS exists in both high and low spin states, as inferred from the ESR and UV−vis studies. This is different from the native cyt c, which shows primarily the low spin state. The high spin state arises from the replacement of Met-80 ligands of heme Fe (III) by water or silanol group on silica surface, which could open up the heme groove for easy access of oxidants and substrates to iron center and facilitate the catalytic activity. In the catalytic study, MAS-9-cyt c showed the highest specific activity toward the oxidation of polycyclic aromatic hydrocarbons (PAHs), which arises from the fast mass transfer rate of reaction substrate due to its large pore size. For pinacyanol (a hydrophilic substrate), MCM-41-S-cyt c and MCM-48-S-cyt c showed higher specific activity than NaY-cyt c and MAS-9-cyt c. The result indicated that cyt c embedded in the channels of MCM-41-S and MCM-48-S was protected against unfolding and loss of activity. By increasing the concentration of the spin trapping agent, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in ESR experiments, we showed that cyt c catalyzes a homolytic cleavage of the O−O bond of hydroperoxide and generates a protein cation radical (g = 2.00). Possible mechanisms for MPS-cyt c catalytic oxidation of hydroperoxides and PAHs are proposed based on the spectroscopic characterizations of the systems.
A full-cyclic automatic control strategy for sequencing batch reactors (SBR) was proposed using only common sensors such as ORP, DO and pH. The main objective was to develop a generally applicable ...and robust control strategy. To accomplish this, various control schemes found in the literature or suggested by authors were examined at diverse ammonia loads and SCOD/NH4(+)-N ratios. Advantages and constraints of each scheme were discussed and compared. Ammonia load was estimated with DO lag time during the aerobic stage, and then the influent pump was manipulated to meet the desired load at the next anoxic stage. A partial denitrification scheme was chosen for the anoxic stage period control, to save anoxic time and external carbon. For external carbon dosage control, intermittent feeding at each anoxic stage was concluded to be a suitable scheme. The anoxic stage period could be successfully controlled by the combination of pH increase and DO increase. Every suggested control scheme was incorporated into a full-cyclic control strategy and tested at 0.02, 0.035, 0.08 kg NH4(+)-N/m3/sub-cycle. From the results, it is expected to perform unmanned automatic SBR operation with this strategy.
The structure–activity relationships of flavonoids with regard to their inhibitory effects on phosphodiesterase (PDE) isozymes are little known. The activities of PDE1–5 were measured by a two-step ...procedure using cAMP with
3
H-cAMP or cGMP with
3
H-cGMP as substrates. In the present results, PDE1, 5, 2, and 4 isozymes were partially purified from guinea pig lungs in that order, and PDE3 was from the heart. The IC
50 values of PDE1–5 were greater than those reported previously for the reference drugs, vinpocetin, EHNA, milrinone, Ro 20-1724, and zaprinast, by 5-, 5-, 7-, 5-, and 3-fold, respectively. As shown in Table 2, luteolin revealed non-selective inhibition of PDE1–5 with IC
50 values in a range of 10–20
μM, as did genistein except with a low potency on PDE5. Daidzein, an inactive analogue of genistein in tyrosine kinase inhibition, showed selective inhibition of PDE3 with an IC
50 value of around 30
μM, as did eriodictyol with an IC
50 value of around 50
μM. Hesperetin and prunetin exhibited more-selective inhibition of PDE4 with IC
50 values of around 30 and 60
μM, respectively. Luteolin-7-glucoside exhibited dual inhibition of PDE2/PDE4 with an IC
50 value of around 40
μM. Diosmetin more-selectively inhibited PDE2 (IC
50 of 4.8
μM) than PDE1, PDE4, or PDE5. However, biochanin A more-selectively inhibited PDE4 (IC
50 of 8.5
μM) than PDE1 or PDE2. Apigenin inhibited PDE1–3 with IC
50 values of around 10–25
μM. Myricetin inhibited PDE1–4 with IC
50 values of around 10–40
μM. The same was true for quercetin, but we rather consider that it more-selectively inhibited PDE3 and PDE4 (IC
50 of <10
μM). In conclusion, it is possible to synthesize useful drugs through elucidating the structure–activity relationships of flavonoids with respect to inhibition of PDE isozymes at concentrations used in this in vitro study.
The aim of this study was to explore the expression of peroxiredoxin1 (PRDX1) in epithelial ovarian cancer, analyze the relationship between PRDX1 and clinicopathologic parameters of patients with ...ovarian cancer, including their prognosis, and describe changes and the mechanisms involved in malignant biologic behavior of ovarian cancer cells when PRDX1 expression is inhibited.
The expression of PRDX1 was detected immunohistochemically in 15 samples of normal ovarian tissue, 21 benign, 11 borderline, and 101 malignant epithelial ovarian tumors. Changes in ovarian cancer cell proliferation, invasion, and metastasis before and after inhibiting PRDX1 expression were assessed by cell function assay. Additionally, gene set enrichment analysis (GSEA) of PRDX1 was performed by the Cancer Genome Atlas database. A protein- protein interaction network was then constructed and a pathway function analysis of the genes in the network was conducted.
PRDX1 expression was mainly localized to the cytoplasm, as well as the nucleus of cells. The expression rate of PRDX1 in epithelial ovarian malignant tissues (96.04%) was significantly higher than that in borderline (72.72%) and benign (57.14%) epithelial ovarian tumors, and normal ovarian tissue (20%; all
<0.05). Cox multivariate regression analysis indicated that advanced clinical stage, low tissue differentiation, and high expression of PRDX1 were independent risk factors affecting the prognosis of epithelial ovarian cancer (all
<0.05). Cell function assay verified that the decreased expression of PRDX1 inhibited ovarian cancer cell proliferation, invasion, and metastasis. GSEA analysis indicated that PRDX1 was significantly related to the Wnt signaling pathway. Western blot analysis confirmed that PRDX1 could regulate the expression of β-catenin in the Wnt pathway.
Decreased expression of PRDX1 can attenuate cell proliferation, invasion, and metastasis of ovarian cancer cells. The expression of PRDX1 is related to the prognosis of patients with ovarian cancer and can therefore be used as a biomarker.
PDF
