- Titration of Aerosol pH Through Droplet Coalescence. [Journal Article]
- JPJ Phys Chem Lett 2019 Jul 12
- The pH of aqueous aerosols, as well as cloud and fog droplets, has an important influence on the chemistry that takes place within these unique microenvironments. Utilizing conjugate acid/base pairs …
The pH of aqueous aerosols, as well as cloud and fog droplets, has an important influence on the chemistry that takes place within these unique microenvironments. Utilizing conjugate acid/base pairs to infer pH changes, we investigate, for the first time, changes in aerosol pH upon droplet coalescence. In particular, we show that the pH within individual aqueous aerosol droplets that are ~8 μm in diameter can be titrated via droplet coalescence in an Aerosol Optical Tweezer (AOT). Using sulfate/bisulfate and carbonate/bicarbonate as model systems, the pH of trapped droplets is determined before and after introduction of smaller droplets containing a strong acid. The pH change upon coalescence of the acid within the trapped droplet is calculated using Specific Ion Interaction Theory (SIT). Furthermore, we show that the pH of an individual aerosol can be manipulated along a fairly wide range of pH values, paving the way for future studies requiring rigorous pH control of aqueous aerosol.
- Detailed Analysis of Estimated pH, Activity Coefficients, and Ion Concentrations between the Three Aerosol Thermodynamic Models. [Journal Article]
- ESEnviron Sci Technol 2019 Jul 11
- In this work, we utilize a rich set of simulated and ground-based observational data in Tianjin, China to examine and compare the differences in aerosol acidity and composition predicted by three pop…
In this work, we utilize a rich set of simulated and ground-based observational data in Tianjin, China to examine and compare the differences in aerosol acidity and composition predicted by three popular thermodynamic equilibrium models: ISORROPIA II, the Extended Aerosol Inorganics Model vision IV (E-AIM IV), and the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients model (AIOMFAC). The species used to estimate aerosol acidity for both simulated and ambient data were NH4+, Na+, SO42-, NO3-, and Cl-. For simulated data, there is good agreement between ISORROPIA II and E-AIM IV predicted acidity in the forward and metastable mode, resulting from the hydrogen ion activity coefficient (γ(H+)) and the molality (m(H+)) showing opposite trends. While almost all other inorganic species concentrations are found to be similar among the three models, such is not the case for the bisulfate ion (HSO4-), which is linked to m(H+). We find that differences in predicted bisulfate between the three models primarily result from differences in the treatment of the HSO4- ↔ H+ + SO42- reaction for highly acidic conditions. This difference in bisulfate is responsible for much of the difference in estimated pH for the ambient data (average pH of 3.5 for ISORROPIA II and 3.0 for E-AIM IV).
- Protective Effects of Trimetazidine in Retarding Selenite-Induced Lens Opacification. [Journal Article]
- CECurr Eye Res 2019 Jul 08; :1-12
- CONCLUSIONS: Our findings indicate that the antioxidant TMZ strongly reduces ROS production, which ultimately delays the progression of cataract formation, suggesting that treatment with TMZ represents a novel, promising antioxidant protection to retard cataract formation.
- Box-Behnken design directed optimization for sensitivity assessment of anti-platelet drugs. [Journal Article]
- DDDrug Dev Ind Pharm 2019; 45(9):1515-1522
- Optimization of electrospray ionization (ESI) parameters is routinely carried out by one factor at a time (OFAT) or auto-tune software (ATS). Design of experiments (DOE) approach has been reported to…
Optimization of electrospray ionization (ESI) parameters is routinely carried out by one factor at a time (OFAT) or auto-tune software (ATS). Design of experiments (DOE) approach has been reported to be an excellent alternative to OFAT or ATS. Box-Behnken Design (BBD) was successfully used to optimize ESI parameters like nebulizing gas flow rate, desolvation line temperature, heat block temperature, and drying gas flow rate for [M + H]+ intensity of Clopidogrel bisulfate (CLP) and Ticlopidine (TLP). BBD model was found to be significant with p < .0001 for both CLP and TLP. The predicted and optimized (OL) ESI parameters were used for chromatographic analysis and were compared against three levels of ESI parameters, i.e. low level (LL), medium level (ML), and high level (HL). The OL ESI parameters were subjected to chromatographic analysis and its mean peak area was significantly higher than mean peak area for LL, ML, and HL ESI in case of CLP and TLP (p < .001). However, no significant difference was observed between the mean peak area for ML and OL of TLP. Thus, BBD can be considered with 29 trials to optimize four mass spectrometric parameters. The liquid chromatographic parameters percentage of methanol, percentage of formic acid and flow rate were also optimized using BBD. However, the optimized method did not significantly influence the peak response over the non-optimized method.
- Effects of complexation with sulfuric acid on the photodissociation of protonated Cinchona alkaloids in the gas phase. [Journal Article]
- PCPhys Chem Chem Phys 2019 Jul 17; 21(28):15439-15451
- The effect of complexation with sulfuric acid on the photo-dissociation of protonated Cinchona alkaloids, namely cinchonidine (Cd), quinine (Qn) and quinidine (Qd), is studied by combining laser spec…
The effect of complexation with sulfuric acid on the photo-dissociation of protonated Cinchona alkaloids, namely cinchonidine (Cd), quinine (Qn) and quinidine (Qd), is studied by combining laser spectroscopy with quantum chemical calculations. The protonated complexes are structurally characterized in a room-temperature ion trap by means of infra-red multiple photon dissociation (IRMPD) spectroscopy in the fingerprint and the ν(XH) (X = C, N, O) stretch regions. Comparison with density functional theory calculations including dispersion (DFT-D) unambiguously shows that the complex consists of a doubly protonated Cinchona alkaloid strongly bound to a bisulfate HSO4- anion, which bridges the two protonated sites of the Cinchona alkaloid. UV excitation of the complex does not induce loss of specific photo fragments, in contrast to the protonated monomer or dimer, for which photo-specific fragments were observed. Indeed the UV-induced fragmentation pattern is identical to that observed in collision-induced dissociation experiments. Analysis of the nature of the first electronic transitions at the second order approximate coupled-cluster level (CC2) explains the difference in the behavior of the complex relative to the monomer or dimer towards UV excitation.
- Segmented scan modes and polarity-based LC-MS for pharmacokinetic interaction study between Fufang Danshen Dripping Pill and Clopidogrel Bisulfate Tablet. [Journal Article]
- JPJ Pharm Biomed Anal 2019 May 30; 174:367-375
- Fufang Danshen Dripping Pill (FDDP) and Clopidogrel Bisulfate Tablet (CBT) are usually combined for treatment of coronary artery diseases in clinical. To investigate the pharmacokinetic interaction b…
Fufang Danshen Dripping Pill (FDDP) and Clopidogrel Bisulfate Tablet (CBT) are usually combined for treatment of coronary artery diseases in clinical. To investigate the pharmacokinetic interaction between FDDP and CBT after oral administration of FDDP, CBT and their combination in rats, a novel LC-MS method with segmented scan modes (multiple reaction monitoring and selected ion monitoring) and polarity (positive and negative ionization) was developed. Clopidogrel and the main active ingredients of FDDP, with different chemical and ionization properties, were simultaneously quantified in plasma in a single run. The method was validated in terms of specificity, linearity, precision, accuracy, recovery, matrix effect and stability. As a result, co-administration of FDDP and CBT significantly altered the pharmacokinetic parameters of danshensu, ginsenoside Rb1, dihydrotanshinone I, tanshinone I and tanshinone IIA of FDDP, as well as clopidogrel. Mechanism studies suggested that induction of liver cytochrome P450 isozymes CYP2C11 and CYP3A1 by co-administration, as well as inhibition of carboxyl esterase 1, was partly responsible for FDDP-CBT pharmacokinetic interactions. The developed LC-MS method could be used to simultaneously quantify different types of in vivo analytes in a single run, and the results could be used for clinical medication guidance of FDDP and CBT.
- Data on morphological features change of pre-hydrolysis treated sugarcane bagasse using in-situ sodium hydroxide-sodium bisulfate method. [Journal Article]
- DBData Brief 2019; 24:103971
- The Scan Electron Microscope Images (SEM), X-ray Diffraction and Fourier Transform Infrared Spectroscopy (FTIR) dataset has been outlined investigating morphological features change of native sugarca…
The Scan Electron Microscope Images (SEM), X-ray Diffraction and Fourier Transform Infrared Spectroscopy (FTIR) dataset has been outlined investigating morphological features change of native sugarcane bagasse, as an agro-industrial lignocellulosic feedstock waste and a potential for cellulose biopolymer extraction, pretreated by alkali (sodium hydroxide) followed by an acid step (sodium bisulfate) in an exothermic in-situ one step, pretreated by acid (sulfuric acid) followed by residual solid fraction alkali pretreatment (sodium hydroxide) in a two separate individual steps and finally after the enzymatic cellulolysis. Data explained herein helps to extend and add to knowledge regarding the impact unlikeness of two different pretreatment methodologies utilize the same chemicals and relatively same concentrations on the cellulosic fiber morphological features and consequently its enzymatic accessibility. This data are related to Egypt Patent Office application, 1349/2017, entitled "In-situ sodium hydroxide-sodium bisulfate sugarcane bagasse pretreatment for biofuel production",Zohri et al., 2017 .
- Stabilizing excipients for engineered clopidogrel bisulfate procubosome derived in situ cubosomes for enhanced intestinal dissolution: Stability and bioavailability considerations. [Journal Article]
- EJEur J Pharm Sci 2019 Aug 01; 136:104954
- Clopidogrel bisulfate (CB) is a golden antiplatelet treatment, yet its benefits are limited by its low bioavailability (<50%) caused by poor intestinal solubility and absorption. The present study ai…
Clopidogrel bisulfate (CB) is a golden antiplatelet treatment, yet its benefits are limited by its low bioavailability (<50%) caused by poor intestinal solubility and absorption. The present study aims to improve CB intestinal solubility and absorption through developing a novel stable dry CB procubosomes tablets ready to disintegrate and re-disperse upon dilution in the GIT forming in situ CB cubosome nanoparticles while simultaneously overcome the poor stability of conventional cubosome dispersion at room temperature. Glyceryl monooleate based CB cubosome dispersion was prepared using Poloxamer 407 as surfactant, freeze dried using different stabilizing excipients (dextrose, mannitol and avicel) then compressed into procubosome tablets. The effect of excipient's physicochemical properties on the flowability, in vitro dissolution and stability at accelerated conditions (40 ± 2 °C/75 ± 5% RH) were evaluated. The prepared procubosomes exhibited an excipient type dependent dissolution profile where Avicel based procubosome tablet CF2 showed the highest in vitro dissolution profile among other excipients used during the freeze drying process. Upon transition to intestinal pH of 6.8 to mimic the drug absorption site, CF2 procubosome Avicel tablet, was able to preserve the enhanced CB release profile (99.6 ± 6.92%) compared to commercial Plavix® where, CB dissolved % dropped dramatically to 79.1 ± 2.45%. After storage for six months, CF2 retained the fresh tablet drug content of 98.5 ± 5.82% and dissolution properties. Moreover, following oral administration in rabbits, CF2 showed higher relative bioavailability (153%) compared to commercial Plavix® with significant higher Cmax,shorter tmax, as well as enhanced antiplatelet activity.
- MicroRNA-9 enhanced radiosensitivity and its mechanism of DNA methylation in non-small cell lung cancer. [Journal Article]
- GENEGene 2019 Aug 20; 710:178-185
- In order to improve the therapeutic effect of non-small cell lung cancer (NSCLC), it is critical to combine radiation and gene therapy. Our study found that the activation of microRNA-9 (miR-9) confe…
In order to improve the therapeutic effect of non-small cell lung cancer (NSCLC), it is critical to combine radiation and gene therapy. Our study found that the activation of microRNA-9 (miR-9) conferred ionizing radiation (IR) sensitivity in cancer cells. Furthermore, increased microRNA-9 promoter methylation level was observed after IR. Our study combined the IR and microRNA-9 overexpression treatment which leads to a significant enhancement in the therapeutic efficiency in lung cancer both in vitro and in vivo. Therefore, it is plausible that microRNA-9 can be used as a novel therapeutic strategy of NSCLC. MTT assay was performed to detect the effect of microRNA-9 on the survival and growth of NSCLC cells. Flow cytometry results showed that microRNA-9 enhanced the apoptosis of NSCLC cells. Wound healing assay found that microRNA-9 can inhibit the migration of NSCLC cells and enhance the effect of radiation on the migration of NSCLC cells. In addition, bisulfate sequencing PCR was performed to analyze the methylation status of the microRNA-9 promoter. In order to determine the effect of microRNA-9 and its promoter methylation status on proliferation and radio-sensitivity in vivo, a subcutaneous tumor formation assay in nude mice was performed. Results have shown that microRNA-9 overexpression increased the radiosensitivity of A549 cells by inhibiting cell activity and migration, and by increasing apoptosis. In addition, the promoter methylation status of the microRNA-9 gene increased in response to ionizing radiation. Our study demonstrated that microRNA-9 enhanced radiosensitivity in NSCLC and this effect is highly regulated by its promoter methylation status. These results will help to clarify regulatory mechanisms of radiation resistance thus stimulate new methods for improving radiotherapy for NSCLC.
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- A dual electron-withdrawing enhanced selective/sensitive chemodosimeter for detection on bisulfate and its living cell imaging. [Journal Article]
- SASpectrochim Acta A Mol Biomol Spectrosc 2019 Sep 05; 220:117148
- Fluorescence detection of sulfur dioxide has attracted great interest from researchers in recent years. Usually double bonds and aldehyde group were employed as reaction sites for sulfur dioxide. In …
Fluorescence detection of sulfur dioxide has attracted great interest from researchers in recent years. Usually double bonds and aldehyde group were employed as reaction sites for sulfur dioxide. In this work, the double bond was linked with cyano and carboxyl group as dual electron-withdrawing to enhance the reaction reactivity between the probe and sulfite. Meanwhile, coumarin with good biocompatibility was introduced as fluorophore. Thus D-π-A form constructs intramolecular charge transfer (ICT), the probe has weak yellow fluorescence emission (565 nm), after addition reaction taking place between the probe and bisulfate, conjugated double bond is broken, the system showed a short-wavelength fluorescence emission (483 nm). All these realized a ratiometric fluorescence detection for bisulfate. The study found that dual electron-withdrawing groups enhanced the specificity and sensibility (with a low detection limit 82 nM) of the probe recognizing bisulfate. These excellent properties led directly to the use of probes to image sulfur dioxide in living cells. Further applications are still being on the way.