Preparation of ISEs often requires long and complicated conditioning protocols limiting their application as tools for in field measurements. Herein, we eliminated the need for conditioning by loading the membrane cocktail with primary ion solution. This protocol significantly shortens the preparation time of ISEs yielding functional electrodes with submicromolar detection limits.The scientific research in ion-selective electrodes (ISEs) has gained momentum within the last years due to improvements in the limits of detection and selectivity, becoming now applicable for trace-level measurements by understanding transmembrane ion fluxes. 1 The response of ISEs can be described by the phase boundary potential, E PB , according the following equation:Here a I (aq) and a I (org) are the activities of primary ion (I) of charge z in aqueous and organic phases respectively, while E 0 , R, T, and F are the standard potential, gas constant, temperature and Faraday constant, respectively. When a I (org) is kept constant, the equation 1 reduces to the well-known Nernst equation:In order to render an ion-selective membrane functional, the ionophore and lipophilic ionic sites are required. One of the major roles of ionophore is to make relatively strong complexes with the primary ion, thereby establishing their constant activity in the membrane. 2 For more details see Equations SI1-SI5 in the supporting information. The role of the lipophilic ionic sites is to provide ion-exchange properties. For cation selective membrane, this process could be described by the following equilibrium:where L is a ligand (ionophore) that forms ion-ionophore complex with ion I of stoichiometry n. + − is a lipophilic ion exchanger composed of lipophilic anion R -and its counterion M + . Partitioning of I from aqueous sample into the membrane results in its exchange with M + . Anion − remains in the membrane thereby rendering the membrane permselective while preserving the charge balance. 3 In a typical experimental protocol for the preparation of ion-selective membranes the ion-exchange process is obtained by conditioning (soaking) the membrane in an aqueous solution containing the ion I (traditional protocol). 4 Significant effort in ISEs field has been spent on researching ways to miniaturize 5-9 and optimize/simplify the preparation of ISEs. [10][11][12] Reducing or eliminating the need for the conditioning step prior to the use of the electrodes is an important step for devising a simple, practical protocol for ISEs applications. 12 This would enable nontrained personnel to use ISEs quickly and reliably. In this work we propose a simple alteration of the sensor's conditioning protocol. Instead of placing the ISEs in a solution of primary ions I, solution is added directly into the membrane cocktail prior to its casting. The concentration of that solution is calculated to allow for stoichiometric exchange of I and M. Consequently, ions I are present in the membrane facilitating the formation of ion-ionophore complex according to the ...

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INTRODUCTION AND OBJECTIVE: Computed-tomography with urography is the standard staging modality for patients with urothelial carcinoma undergoing radical cystectomy (RC). The current TNM classification for nodal stage seems to be insufficient in the prediction of prognosis whereas the ratio of positives lymph nodes (LN) in comparison to all dissected LNs (LNR) has been a new promising approach. Accurate staging is crucial for the planning for therapeutic options and prognosis. We investigated various CT scan characteristics in cNþ patients to further evaluate the LNR and its impact on oncological outcome.METHODS: We analyzed preoperative CT scans of 764 cN0 and 166 cNþ patients undergoing RC in a academic center. Retrospectively, we investigated local tumor stage and LN characteristics such as size, morphology (MLN) and number (NLN) for cNþ patients. Correlation between CT scan criteria, LNR and survival were investigated using Kaplan-Maier and multivariate analysis.RESULTS: Correlation for significant higher LNR in cNþ patients was only revealed for LN size >15mm (p[0.002). Increased number of loco-regional LNs in CT scan correlates with decreased CSS and OS (p[0.001: p[0.002). Furthermore, CT scan based scoring system precisely differentiates low-risk and high-risk profiles to predict oncological outcome (p <0.001).CONCLUSIONS: In our study, solely LN size >15mm significantly correlated with higher LNR. The increased number of locoregional LN was associated with worse survival. To the first time, CT scan based scoring system predicts oncological outcome for clinical lymph node-positive patients undergoing RC.