Maximal Separation Research Articles

Demulsifying super-heavy crude oil with bifunctionalized block copolymers

One of the main problems that petroleum industry must face is the growing difficulty to extract both water and salts present in heavy crude oils. High viscosity, and enormous contents of resins and asphaltenes contribute to stabilize the water droplets dispersed in crude oil, making petroleum demulsification harder and the development of new dehydrating agents necessary. A series of copolymers consisting on a central block polypropylene oxide (PPO), and two side block of ethylene oxide (EO) were synthesized. These copolymers were afterwards submitted to a functionalization process, in order to graft some secondary amines to EO segments, to increase their interactions with the aqueous phase dispersed in the petroleum. The average molecular weight of the functionalized copolymers was adjusted according to the weight-average molecular weight (Mw) of the sample of super-heavy crude oil. The water removals from the petroleum sample were evaluated by bottle testing, mainly varying the kind of functional group and copolymer content. It was observed that these novel demulsifying agents have a better performance than traditional compounds, such as non-functionalized block copolymers and commercial formulations commonly used to remove water from super-heavy crude oil. The existence of maximal water separation at a certain concentration of the functionalized copolymers was observed, and explained in terms of a saturation of the water/oil interphase with polymeric chains.

Use of polarizability and chemical hardness to locate the transition state and the potential energy curve for double proton transfer reaction: A DFT based study

Density functional theory (DFT) based calculations on a series of double and single proton-transfer reactions e.g. formamide (FA), acetamide (AA) and trifluoro acetamide (TFA) dimmers are performed to understand the potential energy surfaces during proton transfer processes. Apart from using the N–H distances as proton transfer co-ordinate we have computed the variations in polarizations and chemical hardnesses of the species involved to locate the transition state structures during the double proton transfer reactions. The average polarizability (αav) and the chemical hardness (η) show their optimum value at the same N–H distance and it corresponds to the transition state for all the three titled complexes. The maximum polarizability and minimum chemical hardness at the transition state (TS) are due to maximal charge separation at TS. We observe that computation of maximum polarizability and minimum chemical hardness along the reaction co-ordinate are the easiest way to locate the transition state during the proton transfer processes.

The Right Ventricular Septum Presents the Optimum Site for Maximal Electrical Separation During Left Ventricular Pacing

Cardiac resynchronization therapy (CRT) benefits selected heart failure (HF) patients. The optimal placement of the right ventricle (RV) lead during biventricular pacing has not been assessed. Greater electrical separation (ES) between left ventricle (LV) and RV leads has been associated with better clinical outcomes. The site of maximal electrical separation(MES) in the RV is unknown. Prospective study of 50 CRT patients. The LV lead was placed in a postero-lateral branch of the coronary sinus. ES was recorded at 6 sites within the RV during LV pacing at 600 milliseconds cycle length (CL). The median ES was recorded with a roving deflectable catheter at the RV outflow tract (RVOT), high septum, inflow septum, mid-septum, apical septum and apex. Mean age was 67 ± 7 years, 39 were male (78%). Thirty had ischemic etiology (60%). Mean left ventricular ejection fraction (LVEF) was 25 ± 7%, QRS duration pre and post was 165 ± 26 milliseconds and 138.5 ± 15.6 milliseconds (P < 0.001). Mapping ES showed a difference between 20 and 50 milliseconds distributed across the RV in the majority of patients (40/49). However, 7 subjects demonstrated delay distribution of between 50 and 82 milliseconds. ES was significant greater in the RV mid-septum (161.2 ± 23.7 milliseconds) compared with RVOT (154.1 ± 20.8 milliseconds) and apex (148.0 ± 25.5 milliseconds; P < 0.001). The site of Maximal ES was most commonly found at the mid-septum (40 patients, 80%) and only rarely at the RVOT (5, 10%) and apex (5, 10%; P < 0.01). MES was observed most commonly at the RV septum and rarely at the RV apex. Better correction of electrical and mechanical dyssynchrony by CRT may be achieved by placing the RV lead in a site outside of the apex in the majority of patients. Clinical studies exploring RV septal pacing in CRT seem warranted.

Preparation and benchmarking of thin film supported PTMSP-silica pervaporation membranes

Supported silica filled poly[1-(trimethylsilyl)-1-propyne] (PTMSP) membranes were optimised in terms of silica filler loading and top layer thickness, and applied in the pervaporative separation of dilute aqueous ethanol and butanol mixtures (5 wt.%). Addition of hydrophobic silica clearly increased the permeate flux at the expense of the alcohol/water selectivity. Based on its maximal pervaporation separation index (PSI) an optimum was found for a 25 wt.% silica filled membrane with a PTMSP separating layer of 2.4 μm thickness. This membrane exhibited a flux of 9.5 kg m −2 h −1 in combination with an ethanol/water separation factor of 18.3. In the pervaporation of a butanol/water mixture, a flux of 9.5 kg m −2 h −1 and accompanying separation factor of 104 was obtained. A benchmark of this optimised supported PTMSP-silica nanohybrid membrane against two commercially available PDMS-based membranes clearly demonstrated the superior flux/selectivity combination of the prepared thin film silica filled PTMSP membranes in the removal of alcohols from dilute aqueous mixtures. Compared to the commercial membranes, a 4- and 3-fold increase in flux and a 2- and 3-fold increase in alcohol/water separation factor was observed for the optimised supported PTMSP-silica membrane in the separation of a 5 wt.% ethanol/water and butanol/water mixture, respectively.

Back Cover: DNA-Linked Nanoparticle Building Blocks for Programmable Matter (Angew. Chem. Int. Ed. 39/2011)

Assembly of nanostructures by using DNA has the potential to realize new materials. In their Communication on page 9185 ff., J.-W. Kim et al. introduce a simple and sustainable strategy to place DNA linkers at 90° or 180° angles on nanoparticles, thus producing a nanoscale building block that allows control of the nanoassembly geometry. The picture depicts the iterative process of DNA attachment at maximal separation resulting in DNA linkers at well-defined orientations. (Artwork by Min Kim.)

Preparation and adsorption selectivity of rutin molecularly imprinted polymers

AbstractMolecularly imprinted polymer (MIP) for Rutin had been prepared through solution polymerization by redox initiation. The effects of monomers, crosslinker, initiators, polymerization time, and temperature on adsorption selectivity for Rutin were investigated and optimized. The structure and surface morphology of MIP were evaluated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The synthesized MIP under the optimal conditions showed a specific recognition of Rutin from the mixture of Rutin and Isorhamnetin. And the maximal separation degree of Rutin was 5.0. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A novel strategy to improve systemic oxygenation in venovenous extracorporeal membrane oxygenation: The “χ-configuration”

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is used in refractory acute respiratory distress syndrome where lung recovery is the primary goal. For its achievement, adequate extracorporeal blood flow and a maximal separation between oxygenated (inflow) and deoxygenated (outflow) blood flow are essential for reducing the recirculation phenomenon. We introduce the χ-configuration, a new cannulation strategy for VV-ECMO. We report our experience with 30 VV-ECMO consecutive patients: in 16 patients (group NS) we applied the χ-configuration, which consists of a particular right atrial cannula arrangement and a self-made modified inflow cannula, consisting of an outflow multihole venous cannula that was inserted percutaneously through the right femoral vein, into the right atrium, just below on the superior vena cava, and a self-made modified curved inflow cannula (inserted percutaneously through the right internal jugular vein) that, in its terminal segment, permitted the tip to be positioned close to the tricuspid valve. In 14 patients (group C) we applied the standard femoro-jugular VV-ECMO 2-cannula setting. In both groups, efficacy of blood oxygenation was obtained by gas-blood analysis, by blood samples obtained at arterial, central venous, and pulmonary artery lines, and by ECMO inflow and outflow lines. The recirculation fraction was obtained by a specific bedside formula. No differences were noted between groups regarding the pre-ECMO patient characteristics. No complications during cannulation were recorded. In group NS, on-ECMO time, post-ECMO mechanical ventilation time, and ECMO overall results were significantly better than in group C. During high-flow VV-ECMO, pulmonary and systemic arterial oxygen saturation and arterial oxygen tension were significantly higher in group NS, and blood recirculation fraction was significantly lower. Our data indicate that χ-configuration can be safe, feasible, and more effective than conventional VV-ECMO. It permits near complete drainage of the desaturated blood and a preferential oxygenated blood inflow toward the tricuspid valve, resulting in a significant reduction of recirculation, thereby improving the patient's oxygenation. Our innovative strategy reduces on-ECMO and post-ECMO mechanical ventilation time, gives a faster and better pulmonary recovery, improves survival, and can reduce hospital costs.

The errant life of a heavy quark in the quark–gluon plasma

In the high-temperature phase of QCD, the heavy-quark momentum diffusion constant determines, via a fluctuation–dissipation relation, how fast a heavy quark kinetically equilibrates. This transport coefficient can be extracted from thermal correlators via a Kubo formula. We present a lattice calculation of the relevant Euclidean correlators in the gluon plasma, based on a recent formulation of the problem in heavy-quark effective field theory (HQET). We find a≈20% enhancement of the Euclidean correlator at maximal time separation as the temperature is lowered from 6Tc to 2Tc, pointing to stronger interactions at lower temperatures. At the same time, the correlator becomes flatter from 6Tc down to 2Tc, indicating a relative shift of the spectral weight to lower frequencies. A recent next-to-leading order perturbative calculation of the correlator agrees with the time dependence of the lattice data at the few-per cent level. We estimate how much additional contribution from the ω≲T region of the perturbative spectral function would be required to bring it in agreement with the lattice data at 3.1Tc.

Sensitivity versus block sensitivity of Boolean functions

Determining the maximal separation between sensitivity and block sensitivity of Boolean functions is of interest for computational complexity theory. We construct a sequence of Boolean functions with bs ( f ) = 1 2 s ( f ) 2 + 1 2 s ( f ) . The best known separation previously was bs ( f ) = 1 2 s ( f ) 2 due to Rubinstein. We also report results of computer search for functions with at most 13 variables.

Fuzzy data mining for segmentation and profiling

The paper presents fuzzy data mining for churn behavior analysis in telecom. Fuzzy data mining is used to identify the clusters in the given large dataset using the modified single pass fuzzy clustering algorithm. Subsequently, fuzzy rule induction is used to reveal variables that provide maximal separation between churners and non-churners in different clusters. This study provides evidence against extra resources for handling large data. The preliminary results are encouraging. The quality of clusters and rules derived for classification are almost identical on both the proposed approach and the original Fuzzy C-Means algorithm.

An objective function utilizing complex sparsity for efficient segmentation in multi‐layer oscillatory networks

PurposeThe purpose of this paper is to extend an analysis presented in earlier work which investigated the dynamical behavior of a network of oscillatory units described by the amplitude of and phase of oscillations, and to present an objective function that can be successfully applied to multi‐layer networks.Design/methodology/approachIn this paper, an objective function is presented that can be successfully applied to multi‐layer networks. The behavior of the objective function is explained through its ability to achieve a sparse representation of the inputs in complex‐valued space.FindingsIt is found that if the activity of each network unit is represented by a phasor in the complex plane, then sparsity is achieved when there is maximal phase separation in the complex plane. Increasing the spread of feedback connections is shown to improve segmentation performance significantly but does not affect separation performance. This enables a quantitative approach to characterizing and understanding cortical function.Originality/valueThe formulation of the multi‐layer objective function and the interpretation of its behavior through sparsity in complex space are novel contributions of this paper.

Atlantoaxial Rotatory Fixation

Atlantoaxial rotatory fixation (AARF) remains a recondite entity. Our normative study using CT motion analysis shows that there is a high degree of concordance for rotational behavior of C1 and C2 in children 0 to 18 years. C1 always crosses C2 at or near 0 degree. The predictable relationship between C1 and C2 is depicted by 3 distinct regions on the motion curve: when C1 rotates from 0 to 23 degrees, it moves alone while C2 remains stationary at 0 (the single-motion phase). When C1 rotates from 24 to 65 degrees, C1 and C2 move together (the double-motion phase), but C1 always moves faster as C2 is being pulled by yoking ligaments. From 65 degrees onward, C1 and C2 move in unison (the unison-motion phase) with a fixed, maximal separation angle of approximately 43 degrees, the head rotation being carried exclusively by the subaxial segments. Because of this high concordance among patients and a relatively narrow variance from the mean, the physiological composite motion curve can be used as a normal template for the diagnosis and classification of AARF. Using a 3-position CT protocol to obtain the diagnostic motion curve, we identified 3 distinct types of AARF. Type I AARF patients show essentially unaltered ("locked") C1-C2 coupling regardless of corrective counterrotation, with curves that are horizontal lines in the upper 2 quadrants of the template. Type II AARF patients show reduction of the C1-C2 separation angle with forced correction, but C1 cannot be made to cross C2. Their curves slope downward from the right to left upper quadrants but never traverse the x axis. Type III AARF patients show C1-C2 crossover but only when the head is cranked far to the opposite side. Their motion curves traverse the x axis far left of 0 degree (C1 < -20). Thus, type I, II, and III AARF are in descending degrees of pathological stickiness. A fourth group of patients showing motion curve features between normal and type III AARF are designated as belonging to a diagnostic gray zone (DGZ). The AARF patients are further classified as acute if treatment is started less than 1 month from the onset of symptoms, as subacute if the delay in treatment is 1 to 3 months, and chronic if treatment delay exceeds 3 months. The treatment protocol for AARF consists of reduction using either halter or caliper traction and then immobilization with brace or halo, depending on the AARF type and chronicity. Recurrent slippage and irreducibility are treated with C1-C2 fusion. The treatment course and outcome of AARF are analyzed according to the AARF type and chronicity. The difficulty and duration of treatment, the number of recurrent slippage, the rate of irreducibility, the need for halo and fusion, and the percentage ultimately losing normal C1-C2 rotation are significantly greater in type I patients than type III patients, with type II patients somewhere in between. Likewise, all parameters are much worse in patients with any type of chronic AARF than acute AARF. The worse subgroup is chronic type I versus the best subgroup of acute type III. Recurrent AARF patients do much worse than nonrecurrent AARF patients. Recurrence is, in turn, adversely influenced by both the severity (type) and chronicity of AARF. The symptoms of most DGZ patients will resolve with analgesics, but a few remain symptomatic or deteriorate to true AARF requiring the full treatment. Thus, children with painful torticollis should undergo the 3-position CT protocol not only to confirm the diagnosis of AARF but also to grade its severity. Closed reduction with traction should be instituted immediately to avoid the serious consequences of chronicity. Proper typing and reckoning of the pretreatment delay are requisites for selecting treatment modalities. Recurrent dislocation and incomplete reduction should be treated with posterior C1-C2 fusion in the best achievable alignment.

Adenovirus Virion Stability and the Viral Genome: Size Matters

Ongoing investigations into the fundamental aspects of virus biology continue to provide crucial insights for the development of more effective virus-based therapeutics. Within the field of gene therapy, these discoveries have translated into virus vectors with improved tissue tropism, prolonged transgene expression, and enhanced safety. However, radical modifications to the viral genome or capsid constituents can have marked effects on virion stability. In particular, recent insights into the role of viral genomes in contributing to the physical stability of the virion highlight the need to reconsider this heretofore underappreciated aspect of vector design. Here we discuss the impact of the genome on virion stability, with particular emphasis on the development of adenovirus (Ad)-based vectors.

Feasibility of separation of ternary mixtures by pressure swing batch distillation

Feasibility of the pressure swing batch distillation separation of ternary homoazeotropic mixtures in different single and double column configurations is investigated by assuming maximal separation. Feasibility regions where the ternary mixture can be separated into its pure components (by applying in at least one step pressure swing) and the separation steps for the recommended configurations are determined. The method is presented in details for the most frequent types of ternary mixtures with minimum azeotrope(s).

Associative Conditioning Tunes Transient Dynamics of Early Olfactory Processing

Odors evoke complex spatiotemporal responses in the insect antennal lobe (AL) and mammalian olfactory bulb. However, the behavioral relevance of spatiotemporal coding remains unclear. In the present work we combined behavioral analyses with calcium imaging of odor induced activity in the honeybee AL to evaluate the relevance of this temporal dimension in the olfactory code. We used a new way for evaluation of odor similarity of binary mixtures in behavioral studies, which involved testing whether a match of odor-sampling time is necessary between training and testing conditions for odor recognition during associative learning. Using graded changes in the similarity of the mixture ratios, we found high correlations between the behavioral generalization across those mixtures and a gradient of activation in AL output. Furthermore, short odor stimuli of 500 ms or less affected how well odors were matched with a memory template, and this time corresponded to a shift from a sampling-time-dependent to a sampling-time-independent memory. Accordingly, 375 ms corresponded to the time required for spatiotemporal AL activity patterns to reach maximal separation according to imaging studies. Finally, we compared spatiotemporal representations of binary mixtures in trained and untrained animals. AL activity was modified by conditioning to improve separation of odor representations. These data suggest that one role of reinforcement is to "tune" the AL such that relevant odors become more discriminable.

Degenerate Intermolecular and Intramolecular Proton-Transfer Reactions: Electronic Structure of the Transition States

Density functional theory (DFT) calculations are performed on a series of double and single proton-transfer reactions to study the variation in polarizations in complexes during the dynamics of proton transfer from one isoenergetic, hydrogen-bonded ground-state structure to the other. The isotropic average polarizability (alpha(av)) shows an interesting single-humped profile with a maxima coinciding with the transition state of the reaction. Similar profiles are also computed at Nd:YaG frequencies. The origin of the maximal polarizability at the transition state is traced to maximal charge separation and large D (donor)-A (acceptor) distances. Maximal polarizability for the transition state suggests an interesting, novel, and less memory extensive computational tool to locate the transition state for hydrogen-transfer reactions in hydrogen-bonded complexes.

New double column system for heteroazeotropic batch distillation

A new double column system (DCS) operated in closed mode is suggested for heterogeneous batch distillation. This configuration is investigated by feasibility studies based on the assumption of maximal separation and is compared with the traditional batch rectifier (BR). We study the configurations also by dynamic simulation based on a detailed model using a professional simulator. For the new configuration the minimal duration of the process is determined. The influence of the most important operational parameters is studied. The calculations and the simulations are performed for a binary (n-butanol–water) and for a ternary heteroazeotropic mixture (isopropanol–water + benzene as entrainer). One of the advantages of the DCS is that distillation of binary and ternary systems is performed in only one step. Furthermore the recovery of components is usually higher and the amount of byproducts is lower.

A Network Architecture for Maximal Separation of Neuronal Representations - Experiment and Theory

A Network Architecture for Maximal Separation of Neuronal Representations - Experiment and Theory

Assessment with optical coherence tomography of a new strategy for bifurcational lesion treatment: The Tryton Side‐Branch Stent

The Tryton-Side Branch Stent (Tryton Medical, Inc., Newton, MA, USA) is a dedicated stent designed to provide complete carinal coverage of bifurcational lesions. After implantation of a 18 mm cobalt chromium Tryton stent from the left circumflex into the obtuse marginal branch, recrossing with an everolimus eluting Promus stent and final kissing balloon dilatation, optical coherence tomography (OCT) (LightLab Imaging Inc., Westford, MA, USA) was performed with a non-occlusive technique with motorized pullback (3 mm/s) during continuous pump injection of iso-osmolar contrast, in both LCx and OM1. OCT imaging showed good strut apposition at the level of the carina, with full coverage and no stent protrusion at the ostium of the side branch. Few malapposed struts were present in the proximal main vessel in the segment of stent superimposition, with a maximal separation from to the vessel wall of 160 microm. The implantation of the Tryton-Side Branch Stent allowed full coverage of the side branch ostium with uniform apposition of the stent struts at the level of the carina assessed by OCT.

Aggregation capability of a fluidised layer of granular material during treatment of water with high DOC and low alkalinity

The aim of this contribution is to investigate aggregation efficiencies when a fluidised layer of granular material (FLGM) is applied for a treatment of surface water with high DOC (Dissolved Organic Carbon) and low alkalinity in a pilot size operation. It was shown that the FLGM can be effective for agitation of a system using destabilised particles with the aim to form readily separable suspension. An aggregation efficiency of the FLGM reactor was evaluated by the degrees of destabilisation and aggregation of the particles of impurities. The maximal separation efficiencies of the pilot plant after filtration attained φAl = 0.96 and φDOC = 0.73. These values exceeded not negligibly the ones reported for the conventional aggregation processes.