Self-cleaning and mechanical properties of modified white cement with nanostructured TiO2.

In the present study, self-cleaning and mechanical properties of white Portland cement by addition of commercial available TiO2 nanoparticles with the average particle size of 80 nm were investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET were used to characterize TiO2 nanoparticles. For determination of self-cleaning properties of TiO2-modified white cement, colorimetric tests in decolorization of C.I. Basic Red 46 (BR46) in comparison to unmodified cement samples was applied. The results indicated that with increasing the amount of TiO2 nanoparticles in modified cement, self-cleaning property of the samples increased. The mechanical properties of TiO2-modified and unmodified cement samples, such as time of setting of hydraulic cement, compressive strength of hydraulic cement mortar and flexural strength of hydraulic cement mortar were examined. The results indicated that addition of TiO2 nanoparticles up to maximum replacement level of 1.0% improved compressive and flexural strength and decreased its setting time.

Chemometrics approach for determination and optimization of simultaneous photooxidative decolourization of a mixture of three textile dyes.

In this paper simultaneous photooxidation of three textile dyes (CI Basic Red 46 (BR46), Malachite Green (MG) and CI Basic Blue 3 (BB3)) by UV/H2O2 process is reported. A rapid analytical methodology based on recording UV-Vis spectra during the photooxidative decolourization process and the data treatment using multivariate curve resolution with alternating least squares (MCR-ALS) was developed. The three textile dyes were quantified simultaneously despite the overlap of their spectra. Also, the central composite design was applied for optimization of the photooxidative decolourization of the solution containing three dyes using the UV/H2O2 process. The investigated factors (variables) were the reaction time, initial concentration of the three dyes and initial concentration of H2O2. The optimum initial concentration of the three dyes, H2O2 initial concentration and reaction time were found to be 4 mg/L, 48 mg/L and 30 min, respectively. The photodegradation products of three dyes were identified by the GC-MS technique.

Prognostic Role of Lymphovascular Invasion in Patients with Early Breast Cancer.

In this study, our aim was to evaluate the role of lymphovascular invasion (LVI) in the prognosis of patients with early stage breast cancer. The medical records of more than 7000 patients who suffered from invasive breast cancer and had undergone surgical treatment since December 1994 till December 2019, retrospectively. Patient's history, physical examination and the clinicopathological features, histopathology characteristics, immunohistochemical findings, adjuvant systemic therapy, recurrence rate, metastasis-free survival (MFS), disease-free survival (DFS), and overall survival (OS) were reviewed. A total of 5425 eligible patients were categorized into two groups based on the presence of LVI; 3031 (55.9%) patients had no LVI (group 1) and LVI was present in 2394 (44.1%) patients (group 2), then divided into LN-positive and -negative groups. Presence of LVI was significantly associated with patient age ≤ 40 years (p = 0.048), high histological grade (grades II and III, p < 0.001), tumor size between 2-5 cm and > 5 cm (p < 0.001), number of involved LN ≥ 4 (p < 0.001), and negative ER (p = 0.042) tumors. Five-year OS, MFS, and DFS were 93%, 88.9%, and 76.1% and 85.2%, 84.7%, and 73.6 in groups 1 and 2, respectively (P < 0.001). On multivariate analysis, LVI was an independent prognostic factor for DFS in all patients. Furthermore, histological grade II, histological grade III, and a higher number of involved LNs (≥ 4) were independent predictors in all patients. Thus, the presence of LVI can be considered as an independent prognostic factor for patients with operable breast cancer, irrespective of the LN status.

Applications of capillary electrochromatography analysis for formulated pesticide products.

The feasibility of using capillary electrochromatography (CEC) as a high-efficiency reversed-phase separation technique has been demonstrated for the analysis of some pesticide formulation products. Some operating parameters of CEC analysis (organic modifier content, pH of the buffer, and sample diluent) were studied using commercially available capillaries packed with Hypersil (Phenomenex, Torrance, CA, U.S.A.) octadecylsilic (ODS) particles. It was found that the resolution decreases in linear fashion with the increase in percent acetonitrile in the sample diluent for neutral components if a combination of electrokinetic injection and pressure injection is used. Several practical applications of the CEC technique in the analysis of pesticide formulation products are described in detail. The results indicate that CEC, compared with HPLC, not only has higher efficiency, but is also practical, precise, and accurate in terms of simplicity, efficiency, recovery, and linearity.

Capillary electrophoresis determinative and LC-MS confirmatory method for screening selected imidazolinone herbicides from soil.

Residues of imazapyr, imazamox, imazapic, imazethapyr, imazaquin, and imazamethabenz (meta and para) are extracted from soil with 0.5 N sodium hydroxide. The pH is adjusted to 2.0-2.2, and the resulting precipitate is filtered. Compounds are trapped onto a tC18 solid-phase extraction (SPE) cartridge, then eluted from the cartridge and passed through a strong anion exchange (SAX) SPE cartridge onto a benzenesulfonic acid strong cation exchange (SCX) cartridge using ethyl acetate. After eluting the analytes from the SCX cartridge using saturated potassium chloride in methanol, the solution is evaporated and redissolved in 1% formic acid in water. The sample is then desalted using a tC18 SPE cartridge and eluted with methanol. After evaporating the methanol to dryness, the compounds are partitioned from acidic solution (pH 3.5) into methylene chloride. The methylene chloride is evaporated to dryness and the residues are then dissolved in Milli-Q water (Millipore, Bedford, MA, U.S.A.) in preparation for analysis by capillary electrophoresis. Results are calculated by direct comparison of the sample peak heights to the peak heights of bracketing standards. The validated sensitivity of the method (LOQ, limit of quantitation) is 2.0 ppb for each compound. Confirmation for individual residues greater than 2.0 ppb is provided by liquid chromatography-electrospray ionization mass spectrometry (LC-ESMS) of the final extract.

Yb-doped ZnSe nanoparticles: synthesis, physical properties and photocatalytic activity.

In this study, Yb-doped ZnSe nanoparticles were synthesized by co-reduction method at 150 degrees C and pH = 12 for 24 h. The obtained materials were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Powder XRD patterns indicated that the Yb(x)Zn(1-x)Se crystals (x = 0.00-0.10) are isostructural with ZnSe. SEM and TEM images confirmed doping of Yb3+ into the lattice of ZnSe nanoparticles. The UV-Vis diffuse reflectance characteristics of the Yb-doped ZnSe samples were quite similar to that of the undoped sample and showed a strong photoabsorption at visible light range. The electrical conductivity of Yb-doped ZnSe nanomaterials was higher than pure ZnSe at room temperature, and increased with temperature. The photocatalytic activity of synthesized nanoparticles was investigated by the degradation of Orange II solution under visible light irradiation. It was observed that the color removal efficiency of Yb-doped ZnSe catalyst was much higher than that of pure ZnSe (26.28 and 77.10% after 120 min of treatment for ZnSe and Yb(0.06)Zn(0.94)Se, respectively). The results demonstrated the good photocatalytic ability of synthesized nanoparticles under visible light. Also, it was revealed that the decolorization efficiency of Orange II over Yb-doped ZnSe increased with increasing Yb loading up to 6 mol% and then decreased.

Determination of avoparcin in animal formulations by capillary electrophoresis.

The separation of two closely related glycopeptides, alpha- and beta-avoparcin, which differ by the presence or absence of a Cl atom, is achieved by capillary zone electrophoresis (CZE) using 20 mM borate (pH 9.2) in bare, fused-silica capillaries. The pKa values of these two glycopeptides are determined from spectrophotometric titrations of the mixture. Absorption spectra recorded between pH 3 and 12 produced a maximum pH transition at 258 nm. Titration data fitted to two sigmoidal functions reveal pKas of 7.99 for beta-avoparcin and 10.3 for alpha-avoparcin. The differing pH dependence of the effective electrophoretic mobilities of alpha- and beta-avoparcin resulted in an optimum pH of 9.2 (roughly the average of the pKa values) for their separation. Borate is shown to be necessary for the optimal CZE separation. A linear dynamic range of 0.5-50 ppm is achieved with regression coefficients of 0.9999. The limit of detection ranges from 0.2 to 0.5 ppm using a pressure injection of 15 sec in a 50-cm (effective length) fused-silica capillary with UV detection. Finally, the effects of sodium dodecyl sulfate (SDS) concentration in the migration buffer on apparent mobility, efficiency, migration times, and resolution are discussed. The addition of 75 mM SDS to the running buffer allows baseline resolution of alpha- and beta-avoparcin, including its minor components. Both the CZE and micellar electrokinetic chromatography (MEKC) separations of alpha- and beta-avoparcin are highly reproducible and can readily be applied to the analysis of avoparcin bulk drug and formulated products.