Catalytic nanozyme Zn/Cl-doped carbon quantum dots as ratiometric fluorescent probe for sequential on-off-on detection of riboflavin, Cu2+ and thiamine.

A novel metal-doped Zn/Cl carbon quantum dots (Zn/Cl-CQDs) was developed successfully as ratiometric fluorescent probes for the sequential on-off-on detection of riboflavin, Cu2+ ion and thiamine. The excellent catalytic performance of the Zn/Cl-CQDs nanozyme serves as an ideal platform for sensitive detection of thiamine. Due to the addition of riboflavin to the Zn/Cl-CQDs, the blue emission peak of Zn/Cl-CQDs at 440 nm remains unaffected and used as an internal reference approach, while the green emission peak of riboflavin at 520 nm appeared and increased remarkably. Following the presence of Cu2+, a quenching blue fluorescence signal of Zn/Cl-CQDs was observed which resulted in consequent fluorescent 'turn-off' response toward Cu2+ ion. Finally, upon the addition of thiamine to the above solution under alkaline condition, the blue emission of Zn/Cl-CQDs was gradually recovered. The prepared Zn/Cl-CQDs could act as a nanozyme catalyst for directly catalyzing the oxidation of non-fluorescent substrate of thiamine to produce highly fluorescent substrate of thiochrome. As a result, the blue fluorescence emission peak at 440 nm was recovered. Eventually, the sequential detection properties of ratiometric probes for riboflavin, Cu2+ ion and thiamine were successfully applied in VB2 tablets, drinking water and VB1 tablet with good recoveries of 96.21%, 98.25% and 98.44%, respectively.

Nicotinamide-Functionalized Carbon Quantum Dot as New Sensing Platform for Portable Quantification of Vitamin B12 in Fluorescence, UV-Vis and Smartphone Triple Mode.

Development of an efficient, portable and simple nanosensor-based systems with reliable analytical performance for on-site monitoring of vitamin B12 (VB12) are still major problems and a challenging work for quality control of manufacturers. Herein, a new fluorescence, UV-Vis and smartphone triple mode nanosensors were designed for the simultaneous detection of VB12 with high sensitivity and accuracy. A novel nanosensor was synthesized through nicotinamide-functionalizing of carbon quantum dot (NA-CQDs) by an one-step microwave-assisted method with green approach. The NA-CQDs sensor showed excellent fluorescence properties and wide linear ranges from 0.1-60 µM with the detection limits of 31.7 nM. Moreover, color changes of NA-CQDs induced by the VB12 could also be detected by UV-Vis spectrophotometer and inhouse-developed application installed on smartphone as a signal reader, simultanusly. The Red, Green and Blue (RGB) intensities of the colorimetric images of NA-CQDs/VB12 system which taken by smartphone's camera converted into quantitative values by the application. A smartphone-integrated with NA-CQDs as colorimetric sensing platform displays good linear ranges (4.16 to 66.6 µM) for on-site determination of VB12 with detection limit of 1.40 µM. The method was successfully applied in the determination of VB12 in complex pharmaceutical supplement formulations without any sample pre-treatment and matrix interfering effects. The recovery results (96.52% to 105.10%) which were in agreement with the reference methods, demonstrating the capability of the smartphone-assisted colorimetric sensing platform in many on-site practical applications of quality controls.

Rapid and sensitive fluorescence and smartphone dual-mode detection of dopamine based on nitrogen-boron co-doped carbon quantum dots.

A dual-mode fluorescence and colorimetric biosensor based on nitrogen-boron co-doped carbon quantum dot (N-B CQDs) for rapid and sensitive detection of dopamine (DA) was developed. The quantum dot luminescent materials, N-B CQDs, were prepared by a one-step microwave-assisted method. The N-B CQDs were characterized using SEM, HR-TEM, XRD, FT-IR, Raman, fluorescence, and UV-Vis techniques. The dual-mode assays of fluorescence and colorimetric methods were used for detection of DA. The high fluorescent N-B CQDs mediated turn-off assay for the facile room temperature detection of dopamine via inner filter effect (IFE) and Forster resonance energy transfer (FRET) processes at basic pH. The colorimetric detection of DA was also developed via in-house android application using a smartphone and N-B CQD solution-based nanosensor. The smartphone-based colorimetric biosensors generated more reliable information for quantitative analysis of color changes than the naked eye. Furthermore, a smartphone application with N-B CQD solution-based nanosensor was integrated to monitor the color changes through the DA addition. Wide linear ranges were achieved for DA in the ranges 0.25-50 µM and 5-500 µM with fluorescence and smartphone-based method, respectively. The satisfactory results of the dual-mode detection of DA, not only in aqueous solution, but also in human urine and serum biological sample demonstrated its potential application in biosensing, as a point of care diagnostic tool. Graphical abstract.

Headache in Behcet's disease: types and characteristics.

BACKGROUND: Behcet's disease involves several systems in the body. Neurological involvement is identified by different symptoms. Headache is one of the common complaints of patients with Behcet's disease. It might be a part of neurological involvement or may arise independently in the course of disease. Studies with small sample size have resulted in various findings in this field. Since the prevalence of Behcet's disease is relatively high in Iran, this study was carried out to compare the features of headache between an acceptable number of patients with this rare disease and a control group. METHODS: The current case-control study was performed to compare the features of headache between 312 patients with definite Behcet's disease who referred to a Behcet's clinic and healthy individuals. Patients with Behcet's disease were randomly selected. Controls were matched for age and sex. They were personally examined and interviewed meticulously using a questionnaire that met the standards of the International Headache Society classification for different types of headache. RESULTS: The incidence of headache in the case and control groups was 28.3 % (n = 120) and 18.6 % (n = 59), respectively (p < 0.05; OR 2.73). Tension-type headache was observed in 12.2 % (n = 38) of cases which was significantly higher than control group (n = 6.3 %) (p = 0.011; OR 2.05). The most frequent type of headache in the case group was tension-type headache (12.2 %). In the control group, however, migraine without aura was the most common type (9.1 %). A correlation between ophthalmological involvement and headache was observed in 11 patients in the case group. In addition, a significantly higher systolic blood pressure was found in the case group compared to the controls (125.1 vs. 121.7 mmHg; p = 0.007). There was no major correlation between prednisolone consumption in patients with Behcet's disease and the type and frequency of headache. CONCLUSIONS: Headache, especially tension-type headache, is more common in patients with Behcet's disease. This might be the result of specific types of uveitis-related and non-structural headaches seen in Behcet's disease.

Design of a surface-immobilized 4-nitrophenol molecularly imprinted polymer via pre-grafting amino functional materials on magnetic nanoparticles.

In order to resolve the low adsorption capacity of the surface molecularly imprinting methods, an approach was developed for the preparation of magnetic imprinted polymers by pre-grafting the amino functional material, 3-aminopropyltriethoxysilane (APTES), on the surface of the silica coated magnetic substrate. APTES was used for amino functionalization of the silica coated Fe3O4 nanoparticles. Amino groups were used for immobilization of the template molecules on the magnetic surface and additionally to react with the terminal vinyl groups of cross-linker, ethylene glycol dimethacrylate (EGDMA), by the Michael addition reaction. In this way, the imprinting sites of the analytes formed on the substrate were increased. The sorbent was synthesized in the presence of 4-nitrophenol (4-NP) and EGDMA as the template and cross-linker, respectively. Different parameters affecting the adsorption, such as pH, desorption solvent type and adsorption time were evaluated and optimized. The prepared magnetic molecularly imprinted polymer (MMIP) showed high adsorption capacity and proper selectivity for the template molecule. The kinetic adsorption curve indicated that 90 min was sufficient to achieve the adsorption equilibrium for MMIP. The maximum adsorption capacity was 129.1 mg g(-1). The experiments exhibited a linear range of 10-3000 µg L(-1) for 4-NP with the correlation coefficient (R(2)) of 0.997. The results of the real sample analysis confirmed the applicability of the proposed MMIP for quantitative analysis of 4-NP in the aqueous samples.

Risk factors associated with lipomyelomeningocele: a case-control study.

BACKGROUND: In general, it seems that both genetic and environmental factors play important roles in the induction of neural tube defects. Lipomyelomeningocele (LipoMMC) is a rather common type of closed neural tube defect, but only limited studies have investigated the potential risk factors of this anomaly. Therefore, the purpose of this case-control study was to investigate the risk factors involved in LipoMMC formation. MATERIAL AND METHOD: Various risk factors were evaluated in 35 children between 1 month and 10 years of age with LipoMMC in a hospital-based case-control study. The 2 control arms consisted of 35 children with myelomeningocele (MMC group) and 35 children with congenital anomalies other than central nervous system problems (control group). All groups were matched for age and visited the same hospital. A structured questionnaire was used for the collection of all data, including the mothers' weight and height during pregnancy, education, reproductive history, previous abortions, and socioeconomic status, as well as the parents' consanguinity and family history of the same anomalies. RESULTS: Univariate analysis of the children with LipoMMC compared to the control group showed that the use of periconceptional folic acid supplementation was significantly lower in the MMC and LipoMMC groups compared to the control group. In addition, comparison of the MMC and control groups revealed statistically significant differences regarding the use of folic acid and maternal obesity. In multivariate analysis, use of folic acid in the periconceptional period and during the first trimester was an independent risk factor for LipoMMC and MMC. Furthermore, maternal obesity was a significantly positive risk factor for MMC. CONCLUSION: The probable risk factors for LipoMMC were investigated in this case-control study. Consumption of folic acid in the periconceptional period and during the first trimester is an independent protective factor against LipoMMC. It seems that larger studies are needed to examine other possible risk factors.