3044876
Dual fluorescence self-assembled multilayers bearing a fluorescent internal standard for interfacial sensing.
A novel dual fluorescence film Quartz/PSS/AO/PSS/CS/CdTe sensor was constructed based on layer-layer electrostatic attraction using CdTe as a fluorescence probe. Acridine orange is shielded effectively by sodium poly(4-styrenesulfonate) and chitosan, thus its fluorescence intensity does not change in the presence of the analyte, thereby acting as a fluorescent internal standard providing a reference signal. The ratio of dual fluorescence intensities of the film sensor is not affected by the fluctuation of the external environment factors such as excitation intensity, detector voltage of photo multiplier tube and sensor position in the cell holder. Assays based on this dual fluorescence self-assembled multilayers sensor afforded an extremely high sensitivity for DNA with greatly accuracy.
28366299
Design of fluorescent self-assembled multilayers and interfacial sensing for organophosphorus pesticides.
This paper details the fabrication of indole (ID) self-assembled multilayers (SAMs) and fluorescence interfacial sensing for organophosphorus (OP) pesticides. Quartz/APES/AuNP/L-Cys/ID film was constructed on L-cysteine modified Quartz/APES/AuNP surface via electrostatic attraction between ID and L-cysteine. Cyclic voltammetry indicates that ID is immobilized successfully on the gold surface. Fluorescence of the Quartz/APES/AuNP/L-Cys/ID film shows sensitive response toward OPs. The fluorescent sensing conditions of the SAMs are optimized that allow linear fluorescence response for methylparathion and monocrotophos over 5.97 x 10(-7) to 3.51 x 10(-6)gL(-1) and 3.98 x 10(-6) to 3.47 x 10(-5)gL(-1), with detection limit of 6.1 x 10(-8)gL(-1) and 3.28 x 10(-6)gL(-1), respectively. Compared to bulk phase detection, interfacial fluorescence sensing based on the SAMs technology shows higher sensitivity by at least 2 order of magnitude.
27062674
A novel biosensor for bovine serum albumin based on fluorescent self-assembled sandwich bilayers.
Fluorescent dyes butyl rhodamine B were assembled via a DL-cystenine intermediate onto quartz wafers whose surface had first adsorbed gold nanoparticles. Hence self-assembled sandwich bilayers with nanocomposite structure were constructed which can be used as a biosensor for bovine serum albumin. The biosensor-based self-assembled monolayers (SAMs) are regenerable and have high sensitivity, five orders of magnitude higher than that of bulk solution phase sensing. The effects of existing forms of dyes on the fluorescence spectra of bilayers in the presence of bovine serum albumin were investigated.
41739708
Influence of N-substituent and solvent on internal conversion in 1-aminonaphthalenes.
N-Methyl-N-methoxycarbonylmethyl-1-aminonaphthalene (MMAN) and N,N-dimethoxycarbonylmethyl-1-aminonaphthalene (DCAN) were synthesized and their fluorescence and absorption spectra in solvents of varied polarity were investigated and compared to those of 1-dimethylaminonaphthylene (DMAN). The data were discussed in terms of the N-substitution effects on the internal conversion (IC). Results showed that the IC was enhanced when the N-methyl group in DMAN was replaced by N-CH2CO2CH3.
26818613
A facile and efficient strategy for one-step in situ preparation of hydrophobic organic monolithic stationary phases by click chemistry and its application on protein separation.
A simple one-step in situ "click" modification strategy was developed for the preparation of hydrophobic organic monolithic columns for the first time. The column morphology and surface chemistry of the fabricated monolithic columns were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The chromatographic performances of the C8/C18 "click" monoliths were evaluated through the separation of a mixture of five proteins such as ribonuclease A, soybean trypsin inhibitor, cytochrome c, bovine haemoglobin and bovine serum albumin. Compared with the blank column, the higher hydrophobicity stationary phases obtained from the "clicked" modification have longer retention times and higher resolution for the five proteins. The separation of five proteins mixture on click C18 monolith with gradient elution at different flow rates was also investigated, the baseline separation of five proteins could be achieved at three different flow rates.
31652498
Performance optimization in electric field gradient focusing.
Electric field gradient focusing (EFGF) is a technique used to simultaneously separate and concentrate biomacromolecules, such as proteins, based on the opposing forces of an electric field gradient and a hydrodynamic flow. Recently, we reported EFGF devices fabricated completely from copolymers functionalized with poly(ethylene glycol), which display excellent resistance to protein adsorption. However, the previous devices did not provide the predicted linear electric field gradient and stable current. To improve performance, Tris-HCl buffer that was previously doped in the hydrogel was replaced with a phosphate buffer containing a salt (i.e., potassium chloride, KCl) with high mobility ions. The new devices exhibited stable current, good reproducibility, and a linear electric field distribution in agreement with the shaped gradient region design due to improved ion transport in the hydrogel. The field gradient was calculated based on theory to be approximately 5.76 V/cm(2) for R-phycoerythrin when the applied voltage was 500 V. The effect of EFGF separation channel dimensions was also investigated; a narrower focused band was achieved in a smaller diameter channel. The relationship between the bandwidth and channel diameter is consistent with theory. Three model proteins were resolved in an EFGF channel of this design. The improved device demonstrated 14,000-fold concentration of a protein sample (from 2 ng/mL to 27 microg/mL).
19099233
Intramuscular delivery of antiangiogenic genes suppresses secondary metastases after removal of primary tumors
The success of surgery to remove primary tumors can be compromised by the subsequent outgrowth of metastases. It is recognized that primary tumors secrete antiangiogenic factors that suppress the outgrowth of their daughter metastases. In accord we show here that surgical removal of primary EL-4 lymphomas led to a marked decrease in the levels of circulating angiostatin and endostatin, and promoted the growth of distant nodular tumors. Expression vectors encoding angiostatin and endostatin, formulated with poly-N-vinyl pyrrolidone (PVP), were injected into the tibialis and gastrocnemia muscles, leading to expression of angiostatin and endostatin in muscle fibers. High levels of biologically active exogenous proteins were secreted into the circulation. Intramuscular gene therapy with angiostatin and endostatin plasmids significantly inhibited tumor vascularity and induced tumor cell apoptosis, and thereby suppressed the growth of secondary subcutaneous and disseminated metastatic tumors in the lung and liver. Simultaneous intramuscular delivery of both angiostatin and endostatin plasmids significantly prolonged the survival of mice after removal of primary tumors. These results suggest that intramuscular gene transfer of angiostatin and endostatin might serve as a prophylactic cancer-prevention strategy to combat the recurrence of cancer after surgical resection of primary tumors.
208925980
(S)-N-Phenyl-tert-butanesulfinamide
The asymmetric unit of the title compound, C10H15NOS, contains two independent molecules with similar conformations. In the crystal, molecules are linked in a head-to-tail fashion by N—H⋯O hydrogen bonds into chains running along the b axis. The absolute configuration was assigned on the basis of known chirality of the parent compound.
9163230
Effect of Aspirin on the Expression of Hepatocyte NF-κB and Serum TNF-α in Streptozotocin-Induced Type 2 Diabetic Rats
Aspirin is a kind of anti-inflammatory drug and may be used to reverse hyperglycemia, hyperinsulinemia, and dyslipidemia by improving insulin resistance. We hypothesized that aspirin improves insulin resistance in type 2 diabetes by inhibiting hepatic nuclear factor kappa-β (NF-κB) activation and serum tumor necrosis factor-α (TNF-α). Adult male Wistar rats were randomly divided into four groups: control, untreated diabetic, diabetic treated with metformin (100 mg/kg/day), and diabetic treated with aspirin (120 mg/kg/day). Diabetes was induced by high-fat feeding and a low dose of streptozotocin (30 mg/kg). After treatment, plasma glucose, insulin, lipids, free fatty acids (FFAs) concentrations and serum TNF-α were determined. The expression of NF-κB in hepatocytes was analyzed by immunohistochemistry and western blot. The results showed administration of aspirin caused no significant lowering in fasting glucose level but significant reduction of hepatic NF-κB expression and serum TNF-α level with improved insulin resistance compared to the diabetic group. The relevant analysis showed positive correlation between the expression of homeostasis model assessment-insulin resistance (HOMA-IR) and NF-κB (r = 0.799, P < 0.01); HOMA-IR and serum TNF-α (r = 0.790, P < 0.01). It is concluded that aspirin improves insulin resistance by inhibiting hepatic NF-κB activation and TNF-α level in streptozotocin-induced type 2 diabetic rats.