Boltzmann Function Research Articles

Centrality and rapidity dependences of negative pions in He–C collisions at 4.2 A GeV/c

In the current research paper, we investigated the dependence of [Formula: see text] spectra of [Formula: see text] mesons on centrality of collision and different rapidity [Formula: see text] range. These negative pions are produced in Alpha–Carbon collisions at a momentum of 4.2 A GeV/c. We used Boltzmann and Hagedorn functions for one and two temperature fitting, of transverse momentum spectra obtained from experimental data and Model (Quark Gluon String Model, QGSM) data. By fitting these mathematical functions, we analyzed the change in shape of slopes of [Formula: see text] spectra. The fitting results for spectral temperatures were consistently larger (both in the experiment and QGSM) for the [Formula: see text] spectra of negative pions produced in range of mid-rapidity in comparison with those produced in fragmentation regions of colliding nuclei. It was also observed that extracted spectral temperatures from experimental data have a weak dependence on the collision centrality. The pion spectra can be described nicely by fitting two temperature functions for the experimental [Formula: see text] spectra for whole range and for the interval [Formula: see text]. In the [Formula: see text] range of [Formula: see text], one temperature functions were found sufficient for fitting the experimental [Formula: see text] spectra. The extracted temperatures from experimental data were found more sensitive to the fitting range of [Formula: see text], in contrast with temperatures obtained from QGSM data.

Eulerian steady state solution of boiling curve for impinging water jet on moving hot metal plate

This paper proposes a method for obtaining boiling curve from experimental temperature measurement for an impinging water stream on the moving hot plate without using the inverse method. Using infrared thermography, temperature profiles on the back side of the moving hot metal sheet were measured. On the front side, water impinges on the hot region and induces pre-cooling in the dry region. This experimental setup can be treated as an impinging region of the DC casting. Once the Eulerian steady state is reached, temperature profiles can be approximated as a single curve using Boltzmann function. With this function, energy balance is conducted, including the advection term to obtain the boiling curve. It is observed that the obtained boiling curve is similar to the boiling curve obtained from inverse solution.

Germination and emergence of Neslia paniculata (L.) Desv.

Seed characteristics, either in size or in structure, can affect germination, hence the emergence of a plant species. In the present work germination and emergence of Neslia paniculata, a Brassicaceae species that produces fruits containing one seed covered by a hard fruit coat, was studied. Germination experiments of seed with and without the fruit coat were performed at constant temperatures from 5 to 23 °C under controlled conditions and germination was measured daily. Additionally, seeds were sown in the field and emergence was periodically followed in three sites: Almenar (Spain), Morris (USA) and Riga (Latvia). Both germination and emergence were modelled with Boltzmann and Weibull mathematical functions. Neslia paniculata is a winter species adapted to low temperatures, with low base temperatures for germination (0.79 °C) and emergence (-3.6 °C). Seeds present both physiological and physical dormancy, the latter provoked by a thick fruit coat that prevents the seed from germinating unless it is degraded. In contrast to other Brassicaceae species studied (Camelina microcarpa; Thlaspi arvense), N. paniculata emergence lacked a response to light. This might have been caused by its fruit coat rendering the embryo non-sensitive to light. For this same reason the best emergence models were developed using a hydrothermal time basis. The relatively larger seed size of N. paniculata species explains the need for considering moisture in the soil at deeper layers (8–10 cm) compared to other Brassicaceae (4–6 cm in C. microcarpa and 4–8 cm in T. arvense), as their radicles can elongate deeper before emergence occurs. The factors to be considered for germination and emergence models are seed dormancy characteristics, either physical, physiological or both, seed size, which allow seedlings to reach deeper moist soil layers prior to emergence, and their seed position in the soil, which determines the temperature for germination. This research deepens in the knowledge of the germination and emergence biology of N. paniculata, with new models for parametrizing these stages, which can help in either germination laboratory studies and field emergence predictions, either for control or conservation purposes.

Effect of movement direction on resistance force in granular media

In this study, a cylinder is horizontally immersed in granular media and moved toward different directions. The cylinder experiences a maximum force (Fm) when plunging downward and a minimum force when pulling upward. As the cylinder moves angularly, the force (F) gradually decreases with increasing angle between the cylinder movement direction and gravity (θ). F/Fm behaves similar to a Boltzmann function with θ; this function is independent of cylinder length and movement velocity and is slightly influenced by cylinder diameter and immersion depth. To illustrate the effect of movement angle (θ) on F/Fm, two estimation methods of resistance force are introduced to the angularly moving intruder. The computation results are consistent with experimental data in principle.

Methodology for describing characteristic foam parameters during chemical foaming of Low-density Polyethylene

The micro-cellular foaming of two Low-density Polyethylene (LDPE) composites as the temperature increased from 140 °C to 160 °C was investigated through visualization technology with the XTL-550E OM (optical Microscopy), with which, in situ observations during heating were carried out. The results demonstrated that the relationships of N-t and D-t followed the Boltzmann and Logistic functions with higher correction coefficients beyond 0.97 through non-linear fitting. Also, the three stages (Less-foamed, Fine-foamed and Over-foamed) were obtained by the first and second derivatives of the fitting curve: (1) the first stage was the less-foamed with the rate and driving force for the cell formation as well as the growth increase with temperature; (2) the second stage was the fine-foamed with competitive interaction between the formation rate and the growth rate; (3) the third stage was the over-foamed with the formation rate and driving force at an almost zero value. Moreover, the demarcation points of the three stages by the derivatives were almost consistent with the results through the fitting equation (t0.5 and tmax) and experimentation. By contrast, certain differences existed for the three stages in the two LDPE composites. These were attributed to the heterogeneous nucleation and strengthening towards the LDPE matrix of the nano-Montmorillonite (nano-OMMT).

Seepage and Damage Evolution Characteristics of Gas-Bearing Coal under Different Cyclic Loading–Unloading Stress Paths

The mechanical properties and seepage characteristics of gas-bearing coal evolve with changes in the loading pattern, which could reveal the evolution of permeability in a protected coal seam and allow gas extraction engineering work to be designed by using the effect of mining multiple protective seams. Tests on gas seepage in raw coal under three paths (stepped-cyclic, stepped-increasing-cyclic, and crossed-cyclic loading and unloading) were carried out with a seepage tester under triaxial stress conditions. The permeability was subjected to the dual influence of stress and damage accumulation. After being subjected to stress unloading and loading, the permeability of coal samples gradually decreased and the permeability did not increase before the stress exceeded the yield stage of the coal samples. The mining-enhanced permeability of the coal samples in the loading stage showed a three-phase increase with the growth of stress and the number of cycles and exhibited an N-shaped increase under the stepped-cyclic loading while it linearly increased under the other two paths in the unloading stage. With the increase of peak stress and the accumulation of damage in coal samples, the sensitivity of the permeability of coal samples to stress gradually declined. The relationship between the damage variable and the number of cycles conformed to the Boltzmann function.

Study on the influence of temperature and humidity on radon exhalation from a radon-containing solution

The radon exhalation rate and transfer radon velocity between liquid and gas under different temperature and humidity conditions are investigated. The fitting formulas of radon exhalation rate and temperature and humidity are exponential functions, and each exponent is a 2nd-order polynomial. The fitting formula of transfer radon velocity and temperature is Boltzmann function, and the velocity tends to be stable gradually at 25 °C. The fitting formula of transfer radon velocity and humidity is exponential function whose exponent is a 2nd order polynomial, and the velocity increases at first when the humidity was 0.75, then decreases with increasing humidity.

Investigation of timing characteristics of the imbibition height of remolded coal without gas

ABSTRACTCoal seam infusion is an imbibition process of adding water to the coal. Capillary water absorption by coal can promote gas desorption and reduce the gas content in the coal seam. A reasonable infusion time and arrangement distance of the drill hole can reduce the gas content in the coal seam. Therefore, research on the timing characteristics of the imbibition height of remolded coal containing gas is crucial. However, it is necessary to first study the timing characteristics of the imbibition height of remolded coal without gas. With increasing pressing load, the imbibition height exhibits an increasing trend. The distribution of axial water content of remolded coal with height can be described with a Boltzmann function having a shape similar to an inverted S-curve. The fitting degree with considering the effect of gravity factor is better than that without considering the effect of gravity factor. This study presents a theoretical foundation for future investigation of imbibition characteristics of remolded coal containing gas in the laboratory.

Unexpected rotational distribution of the ground electronic state OH(X 2Π) generated by plasma at the interface with liquid water

An unexpected rotational distribution of the ground electronic state OH(X 2Π) was observed by laser-induced fluorescence in a surface barrier discharge in contact with a liquid water interface. Analysis assuming a Boltzmann distribution yielded an unrealistically high rotational temperature above 600 K in the post-discharge phase. This is interpreted as a quasi-Boltzmann rotational distribution that is not in equilibrium with the translational temperature of the background gas. While the peculiarities of rotational distribution of excited OH(A 2Σ+) are known, the presented results show that even the ground electronic state OH(X 2Π) does not always have to be a reliable indicator for spectroscopic thermometry in plasmas containing water. A series of similar observations challenges the usual approach in kinetic models, when the rotational distribution is assumed to follow the Boltzmann function with the temperature of surrounding gas.

ИССЛЕДОВАНИЕ ТОЧНОСТИ И СКОРОСТИ СХОДИМОСТИ АЛГОРИТМОВ СТОХАСТИЧЕСКОЙ ОПТИМИЗАЦИИ ФУНКЦИЙ НА МНОГОМЕРНОМ ПРОСТРАНСТВЕ

The purpose of this paper is to analyze the accuracy of calculations and the amount of time spent on finding optimal values for functions of several variables using the algorithmic stochastic optimization algorithms based on the annealing simulation method. To conduct research by the staff of the Department of General Mechanics of the Lipetsk State Technical University, software has been created that implements algorithms for finding extremal values for functions of several variables. The functional purpose of the software is intellectual support for decision-making in the formation of chemical compositions of cast iron alloys. Optimization is performed on a specific and fixed search area, which is a hyperparallelepiped, the boundaries of the variation in the percentage content of a chemical element in the alloy. In the program, ten modifications of the annealing simulation algorithm are realized, allowing a finite number of steps to make an estimate of the optimal value of the input elements of the function under study on a multidimensional space. In particular, modification of A, B and С algorithm schemes using the Boltzmann and Cauchy distribution functions, as well as the superfast annealing algorithm and the Xin Yao algorithm are implemented. The results of the computational experiment for three different functions are presented: from six, eight and nine variables, a comparative analysis of the proximity of the results to the optimal values for each modification of the algorithm is carried out. The obtained data made it possible to draw conclusions about the advantages and disadvantages of each of the modifications of the stochastic search algorithm. Based on the results of computational experiments, the regularities between the time costs of algorithms and their numerical parameters are determined. With the help of linear regression, analytical dependencies are obtained, which allow estimating the time of the algorithms operation depending on the values of their numerical parameters. The paper contains a number of conclusions about the applicability of stochastic optimization modifications for solving applied problems, the shortcomings of modifications and their dignity are highlighted.

Interaction of two parallel rectangular fires

This paper investigates the flame interaction of two parallel rectangular fires. Multiple propane burners were used to produce parallel fires for experiments. Experimental observations combined with analytical analysis provide a physical interpretation on the mechanism of flame interaction. Three types of flame interaction regimes, namely the “Independent regime”, “Intermittent regime” and “Consistent regime”, are quantitatively identified in terms of the flame merging probability (Pm) extracted from image analysis. These three regimes are further divided into five distinct interaction states including (a) State I, independent flames with no interaction, (b) State II, independent flames that have interaction, (c) State III, flames that have intermittent touch with each other, (d) State IV, partly merged flames, and (e) State V, completely merged flames. It is found that for a given fuel size parameter, the data of Pm in different interaction states versus the dimensionless flame spacing s/zc (s: flame spacing, zc: a characteristic length) cluster well and can be well fitted by Boltzmann function, and the function parameters have definite physical significance. For different interaction states, the dimensionless flame height Zf/Zf0 (Zf0: the flame height of one single fire) is correlated with s/zc. Especially, it is found that when s/zc falls into State II, Zf/Zf0 declines to be a constant due to the competition of two distinct effects induced by flame interaction. The dependence of Zf/Zf0 upon s/zc in different interaction states is fully illustrated. Finally, another dimensionless flame height Zf/D (D: a characteristic size of fuel bed by regarding the two flames as a whole) is formulated as a function of heat release rate for different interaction states.

Experience in Using Stochastic Optimization Methods for Determining Numerical Parameters of Models in Materials Structurization Management Systems

The task of intellectual support of the process of composition formation for materials with a composite structure occurs when designing and operating automated control systems for multi-stage production processes. Such automated systems function in direct interaction with the external environment, and should promptly return the results of processing to the environment in the form of corrective actions or as messages to the user. The need for correct and complete mathematical models and fast, accurate algorithms that solve multistage problems often arises when structuring composite materials. In this case, mathematical models contain sets of numerical parameters and the search for exact values for them presents a complex optimization problem. The purpose of this paper is to investigate the possibility of using stochastic optimization methods to determine the exact numerical values of the calculated parameters of mathematical models that mimic the behavior of a structured composite material with given physico-mechanical characteristics under operating conditions. To carry out the research, special software has been created that implements algorithms for searching for extreme values for functions of several variables. The functional purpose of the software is intellectual support for decision-making in the formation of chemical compositions of cast iron alloys. Another developed system is designed to make effective decisions when designing the composition and structure of composite materials containing discrete fibers. Optimization of the calculated parameters was performed on a definite and fixed search area, which is a hyperparallelepiped. The program implements ten modifications of the simulation algorithm for annealing, allowing for a finite number of steps to make an estimate of the optimal value of the input elements of the function under study on a multidimensional space. In particular, modification of A, B and B algorithm schemes using the Boltzmann and Cauchy distribution functions, as well as the superfast annealing algorithm and the Xin Yao algorithm are implemented. The obtained data allowed to draw conclusions about the advantages and disadvantages of each modification of the stochastic search algorithm..

CONTRAST-EHANCED MRI IN TIME-STRUCTURE ANALYSIS OF MYOCARDIAL DAMAGE IN ACUTE INFARCTION AND EARLY PREHOSPITAL THROMBOLYTIC THERAPY

Purpose:to evaluate the dependence of absolute and relative thickness of damaged myocardium in the acute myocardial infarction (AMI) area from the time interval between oncet of pain and start of intravenous thrombolysis (so-called “pain–needle time”), in AMI patients treated with prehospital intravenous thrombolysis and also later on with subsequent percutaneous coronary angiplasty (PCA) and stenting, using contrast-enhanced MRI of the heart Materials and methods. The study comprised data of CE-MRI studies in 25 patients with theyr first acute myocardial infarction, in whom the pre-hospital thrombolytic therapy (TLT) was carried out in the course of 35–300 min after onset of chest pain, with coronarography and percutaneous coronary angioplasty and stenting after admission to the institute of cardiology. In six patients the TLT was not success ful and in these the restoration of coronary blood flow was obtained only at PCA. In all patients in terms 18–34 hours after TLT the CE-MRI of the heart was carried out using gadobutrol or gadoversetamid, as 0.1 mM per kg of BW, in T1-weighted mode with fat suppression and as inversion-recovery with inversion time adjusted to get the normal myocardium “nulled”. We calculated the segmental extension of damage, the thickness of infarcted irreversibly damaged myocardium and of non-damaged myocardium in the same locations, the index of transmurality, as ratio of thickness of damaged myocardium to the overall wall thickness. We analyzed the dependence of these indices of damage from the time interval between pain oncet and beginning of intravenous thrombolytic therapy (or PCA – when TLT was unsuccessful).Results.The dependence of thickness of non-damaged myocardium from the “pain-needle” time was as exponential as Y = 2.08 + 17.11 · exp(−t/42.4), r = 0.843, p < 0.002. Index of transmurality did depend on the time interval “pain – needle” as Boltzmann function, pretty closely to reverse exponential one: No-reflow zone with absent blood flow in the infarcted area was present only in cases with the “pain–needle” time interval over 70 min. Later on the full or partial restoration of contractility in infarcted segments was observed only if the IT was below 0.55–0.6.Conclusion.CE-MRI delivers adequate quantitative estimates of anatomic transmural extent of myocardial infarction from early acute period of the AMI. The depth of myocardial damage is a function of “pain–needle” time and approaches the half of wall thickness for as short as 55–65 min, determining by this the future prognosis of the mechanical restitution of contractility in the infarcted region. It is suggested the CE-MRI of the heart must be carried out in every patient in whom due to AMI the thrombolytic therapy and/or percutaneous coronary angioplasty has been done, for unbiased myocardium-focused control of efficiency of restoration of coronary arterial patency.

Polymers Diffusivity Encoded by Stimuli‐Induced Phase Transition: Theory and Application to Poly(N‐Isopropylacrylamide) with Hydrophilic and Hydrophobic End Groups

AbstractThe self‐diffusion of various nano‐objects investigated by high‐resolution nuclear magnetic resonance diffusometry proves to be an efficient method for the characterization of dynamics, aggregation kinetic, and matrix morphology. This study investigates how the two‐state model and Boltzmann function approach can be used for the evaluation of the thermodynamic parameters of temperature‐induced phase transition encoded in polymer diffusivity. The characteristics of the phase transition given by the transition temperature, change of entropy, and width of transition are obtained for poly(N‐isopropylacrylamide) (PNIPAm) linear polymers with hydrophilic and hydrophobic end‐group functionalization. The effect of end groups upon the polymer diffusivity is investigated as a function of molecular weight (M n), from which fractal dimensions and hydrodynamic drag coefficients are obtained. The PNIPAm diffusivity is affected strongly by the end groups, and it is reflected in the hydrodynamic radius dependence upon molecular weight that obeys different power‐law relations. In this study, the synthesis of α‐ω‐heterotelechelic PNIPAm of different molecular weights with a thiol end group and a hydrophilic NIPAm‐like as well as a hydrophobic benzyl end group are described by reversible addition–fragmentation chain‐transfer polymerization.

Semi-analytical modelling of linear scan voltammetric responses for soluble-insoluble system: The case of metal deposition

The absence of general theoretical models describing linear sweep voltammetry (LSV) or cyclic voltammetry (CV) responses for soluble-insoluble systems such as one-step electrodeposition reactions under quasi-reversible condition makes it difficult to extract quantitative kinetic information from experimental voltammograms. In this work, a semi-analytical method for modelling LSV responses for one–step electrodeposition process is described, for a case where instantaneous nucleation takes place, such as metal deposition on same metal. Voltammetric peaks were analyzed following variation of both dimensionless rate constants and charge transfer coefficients in a broad range. Therefore, kinetic curves for electron transfer processes were established and fitted perfectly by sigmoidal Boltzmann function and linear models. With these models, LSV or CV experimental data can be used to measure electrodeposition reactions kinetics whatever the degree of reversibility. The Cu(I)/Cu(0) couple in acetonitrile was selected as an experimental example. The model developed in this work predicts accurately the current response for Cu electrodeposition reaction and an excellent experiment–theory agreement was found.

Piezo2 Mechanosensitive Ion Channel Role in Primary Enterochromaffin (EC) Cell Mechanosensitivity

INTRODUCTIONIntestinal enterochromaffin (EC) cells are the specialized epithelial mechanosensors of the gastrointestinal (GI) epithelium and are functionally and developmentally like Merkel cells in the skin. EC cells release serotonin (5‐HT) in response to mechanical stimuli. Recently, we discovered that like Merkel cells, human and mouse EC cells express the mechanosensitive (MS) ion channel Piezo2. However, little is known about the functional properties of this channel in primary EC cells.AIMTo determine the role of Piezo2 in primary EC cells.METHODSThe enteroendocrine cell transcription factor NeuroD1 was used to mark the late stage of EC cell development and generate NeuroD1‐cre::GCaMP5/tdTomato mouse to identify EC cells and examine their Ca2+ dynamics. We examined colocalization of tdTomato with 5‐HT and Piezo2 by immunohistochemistry. We established and used primary colon epithelium cultures for whole‐cell patch clamp and Ca2+ imaging experiments and mechanically stimulated by membrane displacement with a piezoelectrically driven glass probe or shear flow.RESULTSImmunostaining showed no tdTomato labeling outside of the GI epithelium, and epithelial tdTomato cells were 5‐HT+ and Piezo2+. Mechanical stimulation of primary EC cells by membrane displacement produced inward MS currents (20.8±4.9 pA/pF, Cm=3.5 pF, n=6) with fast activation and inactivation kinetics (τinact 11.1±2.8 ms), steep mechanosensitivity (Boltzmann function fit with a mid‐point of 3.46±0.80 μm and slope 0.79±0.27 μm) and a linear current‐voltage relationship (slope 0.61±0.17 pA/mV, x‐intercept −4.26±1.34 mV, n=5). Shear flow (20 s) transiently increased intracellular calcium ((Ca2+)i) (2.15±0.5 ΔF/F0, upstroke 3–5 s, return to baseline in 60 s, n=12). MS currents were inhibited by the MS ion channel blocker Gd3+ (20.8±4.9 pA/pF versus 5.3±1.9 pA/pF), Piezo channel blocker GsMTx‐4 (20.8±4.9 pA/pF versus 2.5±0.9 pA/pF) and Piezo2 siRNA (20.8±4.9 pA/pF versus 1.1±0.3 pA/pF), but not non‐targeted (NT) siRNA (20.8±4.9 pA/pF versus 16.0±5.2 pA/pF and) (n=4–6 for each condition, p<0.05 for all except NT siRNA). Similarly, the (Ca2+)i responses to force were inhibited by Gd3+ (2.28±0.7 ΔF/F0 to 0.09±0.05 ΔF/F0), GsMTx‐4 (2.0±0.6 ΔF/F0 to 0.3±0.1 ΔF/F0), Piezo2 siRNA (2.15±0.5 ΔF/F0 to 0.08±0.05 ΔF/F0), but not NT siRNA (2.15±0.5 ΔF/F0 to 2.7±0.3 ΔF/F0) (n=4–6, p<0.05 for all except NT siRNA).CONCLUSIONSIn the mouse epithelium, Piezo2+ EC cells were specifically marked by NeuroD1. Primary colonic NeuroD1+ cells had inward and non‐rectifying MS currents that could be blocked by Gd3+, GsMTx‐4 and Piezo2 siRNA. Similarly, shear flow evoked changes in (Ca2+)i that were also blocked by Piezo2 inhibitors and dependent on extracellular Ca2+. These results suggest that the MS ion channel Piezo2 acts as the primary EC cell mechanosensor, whose activation by force leads to MS ionic current and (Ca2+)i increase that may mediate mechanically‐induced 5‐HT release.Support or Funding InformationThis work was supported by NIH K08 DK106456, AGA Research Scholar Award, Mayo Clinic Center for Biomedical Discovery, Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567) and DK52766.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Oxytocin Reduction of Nodose Ganglion Neurons Potassium Currents is Enhanced in Chronic Intermittent Hypoxia (CIH)

Oxytocin (OT) from the hypothalamus is increased in several cardiorespiratory nuclei and the circulation in response to a variety of stimuli and stressors, including hypoxia. Oxytocin within the nucleus tractus solitarii (nTS) enhances synaptic transmission, action potential (AP) discharge, and cardiac baroreflex gain to lower heart rate. The baroreceptor reflex is mediated through afferent neurons whose somas originate in the nodose ganglia and project centrally to the nTS. Nodose neurons express the OT receptor, and its activation elevates intracellular calcium; the influence of OT on other ion channels, especially during hypoxia, is not known. The hypoxic stressor obstructive sleep apnea, and its CIH animal model, elevates blood pressure and alters heart rate variability. Recent studies suggest enhancing OT in the dorsal vagal complex during CIH may reduce blood pressure. This study was undertaken to determine the mechanism(s) by which OT modulates sensory afferent‐nTS mediated reflexes normally and after CIH. Nodose neurons of 5–6 wk old male Sprague‐Dawley rats were isolated after 10 d of Normoxia (21% O2, Norm) or CIH (alternating 21% & 6% O2, 8 hr/day). Two‐5 hrs after isolation, we recorded outward potassium currents (IK) and APs by the patch clamp method. To examine IK, neurons were held at −60 mV and currents were evoked by depolarizing voltages (−70 to +60 mV, 140 ms). The steady state IK‐voltage relationship was analyzed. AP discharge was evoked by injecting 50 pA depolarizing steps (−20 to 280 pA, 200 ms); the current‐discharge relationship was evaluated. IK and APs were examined during baseline and after 3 min of vehicle or OT (300, 600, or 1000 nM). Vehicle did not alter IK in Norm (n=6) and CIH (n=4) cells, confirming lack of time‐dependent IK changes. In Norm cells, OT decreased IK at voltages greater than +40 mV (300 nM, n=8) and +60 mV (600 nM, n=7). After CIH, OT (300 nM, n=5) also decreased IK at +40 mV and greater. OT at 600 nM (n=5) attenuated IK at significantly lower voltages (+20 mV) in CIH vs. Norm. OT‐sensitive currents at +60 mV were greater in CIH than Norm at 300 and 600 nM. In Norm and CIH groups (n=4, 5), OT at 1000 nM had variable IK responses which overall were not significantly different from baseline. Fitting IKs to Boltzmann functions demonstrated a reduction in half‐activation during OT in Norm cells. In Norm and CIH cells, application of the K+ channel blocker tetraethylammonium (TEA, 10 mM) decreased IK and blocked the OT‐induced reduction in IK (600 nM, n=3). Depolarizing nodose neurons with up to 280 pA injection induced APs in Norm (n=7) and CIH (n=5) neurons, and 600 nM OT did not alter the number of APs during a given current step. Yet, 600 nM OT decreased AP threshold and tended to increase AP half‐width in CIH but not Norm cells, consistent with the reduction in IK by OT in CIH. In Norm cells, vehicle and OT did not alter holding currents measured at −60 mV, but after CIH 600 nM OT induced modest depolarizing inward currents. Taken together, these data demonstrate OT induces changes in ionic currents in nodose ganglia cells that are consistent with increasing excitability in CIH, and may also shed light on the bradycardic and anti‐hypertensive action of OT.Support or Funding InformationRO1 HL 128454 & HL 098602This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Evaluation of on-stream industrial CO 2 adsorbent in air pretreatment for cryogenic production of oxygen

Abstract This study devises a laboratory testing methodology for commercial CO2 adsorbents to mimic their adsorption behaviors in industrial adsorption chamber. The methodology proposes to use “dense loading procedure” for adsorbent packing, concentrated CO2 feed such as 0.2 vol% CO2, and curve fitting of breakthrough curve using Boltzmann function. Application of the testing methodology for process study including regeneration protocol and dual bed adsorbent ratio of an industrial adsorption chamber has been demonstrated. The loss of breakthrough CO2 capacity is attributed to the weakening of adsorption strength of the processing adsorbent over long on-stream operation.

A ratiometric fluorescence probe for lysosomal polarity

Lysosomal polarity affects the interaction activities between enzymes and substrates at the cellular level. Abnormal lysosomal polarity closely linked with disorders and diseases is worthy of attention. The first fluorescence probe, which can image polarity ratiometrically and detect lysosomal polarity quantitatively, is reported herein. The probe termed NOH can emit dual-peaks both in solvents (λem = 474, 552 nm) and in micro-environment. NOH exhibits the Boltzmann function response of the fluorescence intensity ratio to the polarity in a wide range and localizes at lysosomes specifically (Rr = 0.97). In the method of ratiometric fluorescence imaging with NOH, the variation of lysosomal polarity (Δf) can be directly discerned by the color changes. In virtue of ratiometric fluorescence imaging and the Boltzmann function relationship between the fluorescence intensity ratio and the polarity, lysosomal polarity in MCF-7 cells was calculated to be 0.224 and the polarity in the condition of lysosomal storage disorders (or cell death) could also be obtained. This probe will be a promising tool for studying lysosome-related physiological or pathological processes.

Integrity of Membrane Structures in Giant Unilamellar Vesicles as Assay for Antioxidants and Prooxidants.

We have attempted to evaluate, on the basis of optical microscopy for a single giant unilamellar vesicle (GUV), the potency of antioxidants in protecting GUV membranes from oxidative destruction. Photosensitized membrane budding of GUVs prepared from soybean phosphatidylcholine with chlorophyll a (Chl a) and β-carotene (β-Car) as photosensitizer and protector, respectively, were followed by microscopic imaging. A dimensionless entropy parameter, ΔE, as derived from the time-resolved microscopic images, was employed to describe the evolution of morphological variation of GUVs. As an indication of membrane instability, the budding process showed three successive temporal regimes as a common feature: a lag phase prior to the initiation of budding characterized by LP (in s), a budding phase when ΔE increased with a rate of kΔE (in s-1), and an ending phase with morphology stabilized at a constant ΔEend (dimensionless). We show that the phase-associated parameters can be objectively obtained by fitting the ΔE-t kinetics curves to a Boltzmann function and that all of the parameters are rather sensitive to β-Car concentration. As for the efficacy of these parameters in quantifying the protection potency of β-Car, kΔE is shown to be most sensitive for β-Car in a concentration regime of biological significance of <1 × 10-7 M, whereas LP and ΔEend are more sensitive for β-Car concentrations exceeding 1 × 10-7 M. Furthermore, based on the results of GUV imaging and fluorescence and Raman spectroscopies, we have revealed for different phases the mechanistic interplay among 1O2* diffusion, PC-OOH accumulation, Chl a and/or β-Car consumption, and the morphological variation. The developed assay should be valuable for characterizing the potency of antioxidants or prooxidants in the protection or destruction of the membrane integrity of GUVs.