An Analytical Perspective on Determination of Free Base Nicotine in E-Liquids

In electronic cigarette users, nicotine delivery to lungs depends on various factors. One of the important factors is e-liquid nicotine concentration. Nicotine concentration in e-liquids ranges from 0 to \u3e50 mg/mL. Furthermore, nicotine exists in protonated and unprotonated (“free base”) forms. The two forms are believed to affect the nicotine absorption in body. Therefore, in addition to total nicotine concentration, e-liquids should be characterized for their free base nicotine yield. Two approaches are being used for the determination of free base nicotine in e-liquids. The first is applying a dilution to e-liquids followed by two methods: Henderson–Hasselbalch theory application or a Liquid-Liquid Extraction. The second is the without-dilution approach followed by 1H NMR method. Here, we carried out controlled experiments using five e-liquids of different flavors using these two approaches. In the dilution approach, the Henderson–Hasselbalch method was tested using potentiometric titration. The accuracy was found to be \u3e98% for all five e-liquid samples (n = 3). A Liquid-Liquid Extraction was carried out using toluene or hexane as extraction solvent. The Liquid-Liquid Extraction technique was found to be limited by solvent interactions with flavors. Solvent extractions resulted in flavor dependent inaccuracies in free base nicotine determination (5 to 277% of calculated values). The without-dilution approach was carried out using 1H NMR as described by Duell et al. This approach is proposed to offer an independent and alternative scale. None of the methods have established a strong correlation between pre- and postvaporization free base nicotine yield. Here we present comparative results of two approaches using analytical techniques. Such a comparison would be helpful in establishing a standardized method for free base nicotine determination of e-liquids

Fracture of humerus in a newborn during cesarean section: A case report

Risk of birth injuries and long bone fractures are common in vaginal breech deliveries but have also occurred in the cesarean section. Here, we report the case of a term neonate who was admitted with swelling and paucity of movement of the right arm with a history of energetic traction during the emergency cesarean section. The diagnosis was confirmed by radiography and managed by plaster of paris slab. Obstetrician and pediatrician should remain vigilant regarding such rare complications so that these cases are not overlooked, as timely intervention and management are necessary to prevent disability and deformities in the future

Determination of mass transfer resistances of fast reactions in three-phase mechanically agitated slurry reactors

A methodology for the determination of mass transfer resistances of fast reactions in three-phase mechanically agitated slurry reactors under the reaction conditions is presented. The mass transfer resistances affect significantly the overall mass transfer rate, the design equation and consequently the scale up of the reactor. There is not established methodology to separate the mass transfer resistances under reaction conditions by changing catalyst loading and manipulating the process variables, pressure and agitation speed. This allows to avoid the use of different catalyst particles and give the chance to calculate the mass transfer resistances without caring about the type of catalyst. We calculate each mass transfer resistance under conditions which do not allow to neglect any of the resistances. It is shown that the level off of mass transfer rate which is developed in the plot of mass transfer rate against agitation speed plots is not enough to determine the limiting regime. The hydrogenation of styrene over Pd/C (5% catalyst content) is used as case study to demonstrate the methodology

The Reversal Intervention for Metabolic Syndrome (TRIMS) study: rationale, design, and baseline data

<p>Abstract</p> <p>Background</p> <p>Recent attention has focused on strategies to combat the forecast epidemic of type-2 diabetes (T2DM) and its major vascular sequelae. Metabolic syndrome (MetS) comprises a constellation of factors that increase the risk of cardiovascular disease (CVD) and T2DM. Our study aims to develop a structured self-management education programme for people with MetS, which includes management of cardiovascular and diabetes risk factors, and to determine its impact. This paper describes the rationale and design of the TRIMS study, including intervention development, and presents baseline data.</p> <p>Methods</p> <p>Subjects recruited from a mixed-ethnic population with MetS were randomised to intervention or control arms. The intervention arm received structured group education based on robust psychological theories and current evidence. The control group received routine care. Follow-up data will be collected at 6 and 12 months. The primary outcome measure will be reversal of metabolic syndrome in the intervention group subjects compared to controls at 12 months follow-up.</p> <p>Results</p> <p>82 participants (44% male, 22% South Asian) were recruited between November 2009 and July 2010. Baseline characteristics were similar for both the intervention (n = 42) and control groups (n = 40). Median age was 63 years (IQR 57 - 67), mean waist size 106 cm (SD ± 11), and prescribing of statins and anti-hypertensives was 51% in each case.</p> <p>Conclusion</p> <p>Results will provide information on changes in diabetes and CVD risk factors and help to inform primary prevention strategies in people with MetS from varied ethnic backgrounds who are at high risk of developing T2DM and CVD. Information gathered in relation to the programme's acceptability and effectiveness in a multi-ethnic population would ensure that our results are widely applicable.</p> <p>Trial registration</p> <p>The study is registered at ClinicalTrials.gov, study identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01043770">NCT01043770</a>.</p

Absorption of carbon monoxide with reversible reaction in CuAlCl<SUB>4</SUB>-toluene-complex solutions

The absorption of CO in CuAlCl<SUB>4</SUB>-toluene-complex solutions was studied in a stirred reactor. The reaction was found to occur in a fast reaction regime. The effect of CO partial pressure, CuAlCl<SUB>4</SUB>-toluene-complex concentration and temperature on the rate of absorption was studied. The results have been interpreted using a theoretical model for mass transfer with reversible chemical reaction and the rate parameters were determined. The equilibrium constants were also determined experimentally. An interesting observation showing a decrease in the rate with an increase in temperature was made for this system. This is explained on the basis of a higher activation energy for the reverse reaction. The activation energies evaluated for the forward and reverse reactions are 32.93 and 97.42 kJ/mol, respectively

Absorption of carbon monoxide with reversible reaction in cuprous chloride solutions

This article does not have an abstract

Effect of Flow Aids on Mucoadhesive Properties of Polymeric Discs of Polyoxyethylene and Carbopol 971P

The aim of present study is to investigate the effect of flow aids on the observed in vitro mucoadhesion of two representative polymers; polyoxyethylene and Carbopol® 971P. More recently it has been shown that the addition of small amounts of certain excipients to a mucoadhesive formulation can lead to a substantial decrease in observed mucoadhesion in an in vitro test system, which suggests that formulation of these systems could be crucial in developing successful dosage forms. A series of experiments has been carried out which indicates that the presence of flow aids at high concentrations present in tablets can affect the observed ex-vivo mucoadhesive bond. Magnesium stearate (5%) exerts its negative effect on the mucoadhesion of Carbopol® 971P and polyoxyethylene combination by hindering the hydration of the polymer. Adhesion time of formulation containing 5% magnesium stearate was found 4.7±0.34 h and percent hydration of same formulation was 70.12%.Talc and colloidal silicon dioxide (Aerosil), which do not possess the same hydrophobic properties or have available divalent cations were found to be viable alternatives to magnesium stearate

Gas absorption with exothermic bimolecular (1,1 order) reaction

Gas absorption with a nonisothermal, bimolecular (1,1 order), and irreversible reaction are analyzed and approximate film theory solutions are obtained for interfacial temperature rise and enhancement factor. The model of Mann and Moyes is extended to incorporate depletion of liquid reactant concentration at the gas-liquid interface and also the variation of dissolved gas concentration in the bulk liquid, leading to a generalized solution independent of the regime of absorption. The effect of heat generation, heat dissipation, and reaction rate parameters on enhancement factor and interfacial temperature rise is discussed. The system showed multiplicity behavior under certain conditions, but at higher values of heat dissipation parameters and for some combinations of heat generation and reaction rate parameters, unique solutions were obtained. However, even the unique solutions of enhancement factor are substantially different from the values obtained under isothermal conditions. Since depletion of liquid reactant concentration is incorporated, asymptotic values of enhancement factor (at large &#8730;M ) were observed to be the same as those obtained in the instantaneous reaction regime of isothermal absorption and reaction process. The model presented does not require a priori assumption of the regime of absorption and hence can be useful in modeling nonisothermal reactors