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Turkish Journal of Chemistry 2021This study reports a detailed analysis of an electrode material containing poly(phenolphthalein), carbon nanotubes and gold nanoparticles which shows superior catalytic...
This study reports a detailed analysis of an electrode material containing poly(phenolphthalein), carbon nanotubes and gold nanoparticles which shows superior catalytic effect towards to hydrazine oxidation in Britton-Robinson buffer (pH 10.0). Glassy carbon electrode was modified by electropolymerization of phenolphthalein (PP) monomer (poly(PP)/GCE) and the multiwalled carbon nanotubes (MWCNTs) was dropped on the surface. This modified surface was electrodeposited with gold nanoparticles (AuNPs/CNT/poly(PP)/GCE). The fabricated electrode was analysed the determination of hydrazine using cyclic voltammetry, linear sweep voltammetry and amperometry. The peak potential of hydrazine oxidation on bare GCE, poly(PP)/GCE, CNT/GCE, CNT/poly(PP)/GCE, and AuNPs/CNT/poly(PP)/GCE were observed at 596 mV, 342 mV, 320 mV, 313 mV, and 27 mV, respectively. A shift in the overpotential to more negative direction and an enhancement in the peak current indicated that the AuNPs/CNT/poly(PP)/GC electrode presented an efficient electrocatalytic activity toward oxidation of hydrazine. Modified electrodes were characterized with High-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Amperometric current responses in the low hydrazine concentration range of 0.25-13 µM at the AuNPs/CNT/poly(PP)/GCE. The limit of detection (LOD) value was obtained to be 0.083 µM. A modified electrode was applied to naturel samples for hydrazine determination.
PubMed: 33679162
DOI: 10.3906/kim-2009-12 -
Journal of Orthopaedic Surgery and... Sep 2023The severe rigid scoliosis patients with type I respiratory failure could not tolerate complicated corrective surgery. Preoperative halo-pelvic distraction (HPD) is used...
BACKGROUND
The severe rigid scoliosis patients with type I respiratory failure could not tolerate complicated corrective surgery. Preoperative halo-pelvic distraction (HPD) is used to reduce the curve magnitude and improve the pulmonary function before surgery. The present study aimed to retrospectively analyze the pulmonary and clinical outcomes of preoperative HPD in severe rigid spinal deformity with type I respiratory failure.
METHODS
Eighteen cases of severe rigid scoliosis and type I respiratory failure treated with preoperative HPD and corrective surgery for spinal deformity between 2016 and 2018 were retrospectively reviewed. Patient demographics, major coronal curve and kyphosis, correction rates, heights, pulmonary function, distraction time, and postoperative neurological complications were recorded for all cases.
RESULTS
The averaged duration of distraction was 9.1 ± 2.3 months. The coronal curve was corrected from 168° ± 14° to 58° ± 11° at the end of HPD. The kyphosis curve reduced from 151° ± 29° to 65° ± 10°. Meanwhile, the mean stand body height increased by 23.9 ± 5.3 cm. Significantly increased mean FVC (1.52 ± 0.43 L vs. 0.95 ± 0.44 L) and improved percent-predicted values for FVC (37 ± 10% vs. 23 ± 9%) were observed after HPD. The pressure of oxygen (PaO2) increased from 54.5 ± 2.0 to 84.8 ± 4.7 mmHg. Scoliosis and kyphosis curve, respectively, averaged 48 ± 8°and 30 ± 14° after final fusion and instrumentation, with a mean correction of 71% and 80%, respectively. No severe complication occurred during the distraction.
CONCLUSIONS
HPD may be useful for severe rigid scoliosis patients with type I respiratory failure. Pulmonary functions in patients with severe rigid scoliosis can be significantly improved by HPD. They are then better able to tolerate complicated corrective surgery.
Topics: Humans; Retrospective Studies; Scoliosis; Oxygen; Body Height; Dioctyl Sulfosuccinic Acid; Kyphosis; Phenolphthalein; Postoperative Complications
PubMed: 37735661
DOI: 10.1186/s13018-023-04212-7 -
Forensic Science International Dec 2017The Kastle-Meyer (KM) test is a quick and easy chemical test for blood used in forensic analyses. Two practical variations of this test are the KM-rub (indirect) test...
The Kastle-Meyer (KM) test is a quick and easy chemical test for blood used in forensic analyses. Two practical variations of this test are the KM-rub (indirect) test and the more sensitive KM-direct test, the latter of which is performed by applying reagents directly to a suspected blood stain. This study found that sodium hydroxide present in the KM reagents eliminated the potential to generate a DNA profile when applied directly to small quantities of blood. A modified approach to the KM-rub test that increases its sensitivity is presented as a method to replace destructive KM-direct testing.
Topics: Blood Chemical Analysis; Blood Stains; DNA Damage; DNA Fingerprinting; Humans; Indicators and Reagents; Polymerase Chain Reaction; Sodium Hydroxide
PubMed: 29128654
DOI: 10.1016/j.forsciint.2017.10.006 -
Journal of Forensic Sciences Jan 2022From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among...
From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among these tests, there are different specificities, sensitivities, and shelf lives. The accuracy of a test is an algebraic combination of the specificity and sensitivity of the test. Each test has limitations as given by its false positive and false negative rates. The aim of this study was to illustrate how the false positive and false negative rates are to be properly determined using a simulation study for the phenolphthalein test. New presumptive tests must be properly evaluated/validated through testing of commonly encountered household items and other potentially probative items usually found at crime scenes, however, the makeup of test sets must appropriately capture all error rates. In order to correctly use these results when the test is applied to an unknown sample recovered at a crime scene, the error rates cannot be applied directly to estimate whether or not the sample is actually the analyte of interest. In a validation study, the forensic scientist calculates the false positive rate as the p(Positive Reaction|Blood), whereas at the scene, the crime scene investigator wishes to determine the p(Blood|Positive Reaction). All crime scene investigators need to ensure that the conditional is not transposed when interpreting such results. Furthermore, this work provides a model for the assessment of a multiple test diagnostic system intended for investigators.
Topics: Forensic Medicine; Phenolphthalein; Research Design; Sensitivity and Specificity
PubMed: 34747497
DOI: 10.1111/1556-4029.14924 -
The Journal of Physical Chemistry. B May 2018Templated (T) and nontemplated (NT) cross-linked materials containing β-cyclodextrin (β-CD) and epichlorohydrin (EPH) were prepared at variable β-CD-EPH ratios (1:15,...
Templated (T) and nontemplated (NT) cross-linked materials containing β-cyclodextrin (β-CD) and epichlorohydrin (EPH) were prepared at variable β-CD-EPH ratios (1:15, 1:20, and 1:25) in the presence and absence of a molecular template (toluene). The structural characterization of the materials was carried out using spectroscopy (Fourier transform infrared, solids C NMR, and scanning electron microscopy) and thermogravimetric analysis. The adsorption properties were studied with phenol-based adsorbates (2,4,6-trinitrophenol (TNP) and p-nitrophenol (PNP)) at equilibrium and dynamic conditions. The monolayer adsorption capacity ( Q) varied for the T-polymer/TNP systems ( Q = 0.10-0.95 mmol/g) and NT-polymer/TNP systems ( Q = 0.23-0.83 mmol/g). The range of Q values for the T-polymer/PNP systems (0.26-0.62 mmol/g) exceeded that of the NT-polymer/PNP systems (0.23-0.40 mmol/g). The kinetic uptake profiles for the polymers and phenolphthalein were reliably described by the pseudo-first-order model. The β-CD inclusion site accessibility for the polymers varied from 15 to 20%, according to the level of cross-linking, where the accessibility of the T-polymers exceeded that of the NT-polymers. The structural characterization and phenol adsorption properties provide complementary support for the role of tunable polymer morphology in adsorption processes. The role of two-site binding was demonstrated for linear and globular polymer materials according to their unique adsorption properties with phenols of variable size and hydrophile-lipophile character.
Topics: Adsorption; Epichlorohydrin; Phenols; Polymers; Water Pollutants, Chemical; beta-Cyclodextrins
PubMed: 29634268
DOI: 10.1021/acs.jpcb.8b01819 -
MethodsX 2023Natural, inland alkaline soda waters form a particular type of saline waters, characterized by a permanent alkaline chemical property. In many cases only the total...
Natural, inland alkaline soda waters form a particular type of saline waters, characterized by a permanent alkaline chemical property. In many cases only the total alkalinity by methyl-orange titration is reported, without phenolphthalein titration. Therefore, a reliable estimation of carbonates from total alkalinity is essential for a precise scientific chemical classification. The concentration of bicarbonate [HCO ] can be reliably estimated in waters using the Advanced Speciation Method (ASM) if methyl-orange total alkalinity titration and pH data are available, while the concentration of carbonate [CO ] is not reliably estimated by the ASM when interfering factors with acid/base properties (e.g., phosphate, silicate, ammonia, etc.) are present in significant concentrations in natural waters. Therefore, here I present and prove an experimental polynomial function for carbonate estimation with the following equation based on the concentration of bicarbonate: [CO ] = -2.878E-7 ± 5.438E-8 × [HCO ] + 0.069±0.003 × [HCO ] This Boros's carbonate estimation method can contribute to a more efficient evaluation of field water samples with several analytical difficulties.•Bicarbonate can be reliably estimated using the Advanced Speciation Method (ASM).•Estimation of the carbonate concentration using ASM in the presence of interfering acid/base factors in alkaline waters.•Experimental polynomial function for reliable carbonate estimation in alkaline soda waters.
PubMed: 37095870
DOI: 10.1016/j.mex.2023.102175 -
Polymers Oct 2018A molecularly imprinted polymer (MIP) for highly selective solid-phase extraction (SPE) of bisphenol A (BPA) was prepared using phenolphthalein (PP) as the novel dummy...
A Phenolphthalein-Dummy Template Molecularly Imprinted Polymer for Highly Selective Extraction and Clean-Up of Bisphenol A in Complex Biological, Environmental and Food Samples.
A molecularly imprinted polymer (MIP) for highly selective solid-phase extraction (SPE) of bisphenol A (BPA) was prepared using phenolphthalein (PP) as the novel dummy template by bulk polymerization. A particle diameter distribution of 40⁻60 μm, a specific surface area of 359.8 m²·g, and a total pore volume of 0.730 cm³·g for the prepared PP-imprinted polymer (PPMIP) were obtained. Good selectivity and specific adsorption capacity for BPA of the prepared PPMIP were also demonstrated by the chromatographic evaluation and sorption experiments. The PPMIP as a SPE sorbent was evaluated for the selective extraction and clean-up of BPA from complex biological, environmental, and food samples. Meanwhile, an accurate and sensitive analytical method based on the PPMIP-SPE purification procedure coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) detection has been successfully developed for the rapid determination of BPA from these samples, with detection limits of 1.3 ng·mL for bovine serum and milk, 2.6 ng·mL for human urine and edible oil, 5.2 ng·mL for soybean sauce, and 1.3 ng·g for sediment. The BPA recoveries at two different spiking levels were in the range of 82.1⁻106.9%, with relative standard deviation (RSD) values below 7.7%.
PubMed: 30961075
DOI: 10.3390/polym10101150 -
Analytica Chimica Acta Sep 2017Different phosphate-, acetate- and formate buffers in the pH range 2.0-6.8 were tested for electromembrane extraction (EME) in a 96-well system. The five basic drugs...
Different phosphate-, acetate- and formate buffers in the pH range 2.0-6.8 were tested for electromembrane extraction (EME) in a 96-well system. The five basic drugs haloperidol, loperamide, methadone, nortriptyline, and pethidine were selected as model analytes. The EME performance was tested with respect to extraction recovery, extraction current and pH-stability. The analytes were extracted from 200 μL buffer, through a 100 μm thick supported liquid membrane (SLM) of 2-nitrophenyl octyl ether (NPOE) immobilized in the pores of filters in a 96-well plate, and into 100 μL buffer acceptor phase. The extraction voltage was 50 V and the extraction time was 10 min. The acceptor phase was analyzed by HPLC-UV. The extraction current was ≤6 μA with all buffers, and pH was effectively stabilized during EME using buffers as donor (sample) and acceptor phase. For buffers with pH ≤ 4.8 as acceptor phase, the extraction recoveries were in the range 66-97% and with RSD <15%. With pH in the range 5.8-6.8 in the acceptor phase, the extraction recoveries decreased and were in the range 21-62%. This was attributed to elevated pH conditions in the acceptor/SLM interface. The presence of elevated pH conditions was visualized with phenolphthalein as pH sensitive color indicator. Increasing the buffer strength from 10 to 500 mM in an attempt to offset the elevated pH conditions gave no improvement, and elevated pH conditions remained. Elevated pH conditions in the acceptor/SLM interface were also observed when voltage was increased, and when NPOE was replaced with tributyl phosphate as SLM. The presence of elevated pH conditions close to the SLM in EME was discussed for the first time, and this information is highly important for future development of EME.
PubMed: 28843554
DOI: 10.1016/j.aca.2017.06.049 -
Micromachines Dec 2023The carbonation of concrete greatly affects its service life. In this paper, fiber Bragg grating (FBG) sensors were used to investigate the relationship between concrete...
The carbonation of concrete greatly affects its service life. In this paper, fiber Bragg grating (FBG) sensors were used to investigate the relationship between concrete carbonation and its mechanical properties. A T130 High Sensitivity Strain Cable Sensor with a good linearity was used to monitor the internal strain in concrete, to investigate the variation in the elastic modulus of concrete with carbonation time. A mathematical model of elastic modulus and carbonation time of concrete based on FBG was established. At the same time, the authors explored the relationship between the carbonation depth and compressive strength of concrete and the carbonation time using a phenolphthalein solution test and a compressive strength test, respectively. The experimental results indicate that the carbonation depth, compressive strength, and elastic modulus of concrete increase with carbonation time. In the early stage of carbonation, these three parameters increase rapidly, while they grow slowly in the later stage of carbonation. The varying trend of the elastic modulus of concrete is consistent with the compressive strength, which shows a binomial relationship. Therefore, the elastic modulus, measured using FBG sensors, is used as an indicator of the characterization of the carbonation resistance of concrete. This work provides a new approach for concrete carbonation detection and assessment.
PubMed: 38258147
DOI: 10.3390/mi15010029 -
Molecular Pharmaceutics Apr 2023Despite the recent success of amorphous solid dispersions (ASDs) at enabling the delivery of poorly soluble small molecule drugs, ASD-based dosage forms are limited by...
Despite the recent success of amorphous solid dispersions (ASDs) at enabling the delivery of poorly soluble small molecule drugs, ASD-based dosage forms are limited by low drug loading. This is partially due to a sharp decline in drug release from the ASD at drug loadings surpassing the 'limit of congruency' (LoC). In some cases, the LoC is as low as 5% drug loading, significantly increasing the risk of pill burden. Despite efforts to understand the mechanism responsible for the LoC, a clear picture of the molecular processes occurring at the ASD/solution interface remains elusive. In this study, the ASD/solution interface was studied for two model compounds formulated as ASDs with copovidone. The evolution of a gel layer and its phase behavior was captured with fluorescence confocal microscopy, where fluorescent probes were added to label the hydrophobic and hydrophilic phases. Phase separation was detected in the gel layer for most of the ASDs. The morphology of the hydrophobic phase was found to correlate with the release behavior, where a discrete phase resulted in good release and a continuous phase formed a barrier leading to poor release. The continuous phase formed at a lower drug loading for the system with stronger drug-polymer interactions. This was due to incorporation of the polymer into the hydrophobic phase. The study highlights the complex molecular and phase behavior at the ASD/solution interface of copovidone-based ASDs and provides a thermodynamic argument for qualitatively predicting the release behavior based on drug-polymer interactions.
Topics: Solubility; Drug Liberation; Vinyl Compounds; Pharmaceutical Preparations; Polymers; Drug Compounding
PubMed: 36926898
DOI: 10.1021/acs.molpharmaceut.3c00020