Partition System Research Articles

Liquid Biphasic Electric Partitioning System as a Novel Integration Process for Betacyanins Extraction From Red-Purple Pitaya and Antioxidant Properties Assessment.

Nowadays, downstream bioprocessing industries inclines towards the development of a green and high efficient bioseparation technology. Betacyanins are presently gaining higher interest in the food science as driven by their high tinctorial strength and health promoting functional properties. In this study, a novel green integration process of liquid biphasic electric partitioning system (LBEPS) was proposed for betacyanins extraction from peel and flesh of red-purple pitaya. Initially, the betacyanins extraction using LBEPS with initial settings was compared with that of liquid biphasic partitioning system (LBPS), and the results revealed that both systems demonstrated a comparable betacyanins extraction. This was followed by further optimizing the LBEPS for better betacyanins extraction. Several operating parameters including operation time, voltage applied, and position of graphitic electrodes in the system were investigated. Moreover, comparison between optimized LBEPS and LBPS with optimized conditions of electric system (as post-treatment) as well as color characterization and antioxidant properties assessment were conducted. Overall, the betacyanins extraction employing the optimized LBEPS showed the significant highest values of betacyanins concentration in alcohol-rich top phase (Ct) and partition coefficient (K) of betacyanins from peel (99.256 ± 0.014% and 133.433 ± 2.566) and flesh (97.189 ± 0.172% and 34.665 ± 2.253) of red-purple pitaya. These results inferred that an optimal betacyanins extraction was successfully achieved by this approach. Also, the LBEPS with the peel and flesh showed phase volume ratio (Vr) values of 1.667 and 2.167, respectively, and this indicated that they have a clear biphasic separation. In addition, the peel and flesh extract obtained from the optimized LBEPS demonstrated different variations of red color as well as their antioxidant properties were well-retained. This article introduces a new, reliable, and effective bioseparation approach for the extraction of biomolecules, which is definitely worth to explore further as a bioseparation tool in the downstream bioprocessing.

A Data-Driven Approach Using 911-Call Data to Reconfigure Police Beat Zones

Finding the optimal boundaries of police beat zones is a challenging task due to the dynamic nature of 911-calls that vary over space and time. The lack of a data-driven approach for delineating these boundaries produces non-uniform demand across beat zones, thus resulting in an uneven distribution of workload among officers. We analyzed 911-calls received in a mid-sized Texas city over a period of 4 years and found differences in service call volume serviced by each of the five current beat zones that lead to workload disparities and uneven response times. Readily available 911-service call data integrated into Geographic Information Systems can be used to create boundaries of police beat zones that aim to minimize the differences in the number of service calls originating from each beat zone. Most recently developed approach, the Universal PArtitioning System, was used to produce contiguous spatial partitions of approximately equal call volume resulting in configurations that have a more uniform distribution of calls thus reducing the disparities in officer workload between beat zones. The efficiency of using a computational, data-driven approach allows police to evaluate the impacts of several beat zone configurations on their ability to provide service with respect to available resources.

Study of the Dynamic Characteristics of BWE Based on Products, Difference With a Two-Stage Supply Chain

In previous studies, many researchers have achieved significant success in reducing the negative effects brought about by the bullwhip effect. In this article, the authors have established a supply chain that consists of one supplier and two retailers and has adopted a Cournot-Bertrand mixed duopoly model that successfully combines a nonlinear complexity dynamic system with the bullwhip effect. In order to partition systems with various degrees of disorder and take appropriate methods to refrain systems from falling into a chaos state, numerical simulation methods are conducted to find the stability range, bifurcation range and the chaos range. This article focuses on three different ranges that the authors analyze about the bullwhip effect and inventory variability. In the end, some practical suggestions on behavioral science management are made.

Partitioning the ocean using dense time series of Earth Observation data. Regions and natural boundaries in the Western Iberian Peninsula

Biogeographic partitioning systems provide an important framework under which ocean management practices can be designed and implemented.Sea Surface Temperature (SST) provides important insights into the features and processes governing biogeography and the natural boundaries that separate regions (fronts). In this paper, a new methodology is suggested to segment the ocean at a subset of an Eastern Boundary Current system (Western Iberian Peninsula).To this end, a dense time series of daily MODIS data (Sea Surface Temperature (SST) and Chlorophyll-a concentration, 2003–2014) was analyzed using Dynamic Time Warping (DTW). The resulting dissimilarity matrix was then clustered using UPGMA to generate a set of dynamic regions. To determine whether the boundaries separating regions coincided with areas of maximum frontal activity, a matching time series was produced for the study area.The methodology successfully delivered a set of nested regions, explained by known oceanographic features and separated by natural boundaries collocated with frontal activity maxima (ANOVA, p < 0.01). The frontal activity, which was also found to be spatially organized (Moran’s I > 0.82 and z-score > 6.95, for a p < 0.01) was thus correlated with the dissimilarity patterns of SST. Together, they offer a new perspective into the biogeographic constraints influencing an important ecosystem.SST-based regions were more informative (k = 4) but both the Chlorophyll-a and the multivariate (SST and Chlorophyll-a) alternatives reproduced the coastal/oceanic dichotomy of established systems in a dynamic way. The method was also applied to yearly subsets, which generally matched the regions delineated with the full time series while depicting inter-annual variability.The DTW and the frontal activity maps contributed to the definition of a scalable and ecologically-meaningful system, which can be adopted for the monitoring of marine areas using different (annual to decadal) time scales and easily accessible datasets.

In Vitro Mechanistic Study of the Distribution of Lascufloxacin into Epithelial Lining Fluid.

The present study aimed to clarify the mechanism underlying the high distribution of lascufloxacin in epithelial lining fluid (ELF). Involvement of transporters was examined by transcellular transport across Calu-3 and transporter-overexpressing cells; the binding of lascufloxacin to ELF components was examined by an organic solvent-water partitioning system that employed pulmonary surfactant and phospholipids. Transcellular transport across the transporter-overexpressing cells indicated lascufloxacin to be a substrate of both P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP); therefore, its transport across Calu-3 cells was inhibited by P-gp and BCRP inhibitors. However, permeability and efflux ratios of lascufloxacin were similar to those of the other quinolones with relatively low ELF distribution, indicating the existence of another mechanism for lascufloxacin distribution in ELF. Amongst pulmonary surfactants, which are a primary component of ELF, lascufloxacin preferentially bound to phosphatidylserine (PhS) from several phospholipids, and the binding was significantly greater than that for other quinolones. This binding was saturable with two apparent classes of binding sites and inhibited by some weakly basic drugs, indicating the presence of an ionic bond. In conclusion, the results of this study suggest that the binding of lascufloxacin to PhS in the pulmonary surfactant is the major mechanism of the high distribution of lascufloxacin in the ELF.

Insights into the DNA sequence elements required for partitioning and copy number control of the yeast 2-micron plasmid.

The yeast 2-micron plasmid is an almost perfect selfish DNA. The entire coding capacity of the plasmid is dedicated to ensuring its own inheritance, with no benefit to its host. Despite high copy number, the plasmid confers no phenotype. It manages this feat by possessing mechanisms for plasmid copy-number control and for partitioning. The former increases plasmid numbers when they fall, but is repressed at high copy number, while the latter ensures 2-micron copies are equally partitioned during host cell division. Although the plasmid amplification mechanism is well established, the partitioning system and the means by which the 2-micron plasmid partitioning proteins, Rep1 and Rep2, regulate plasmid copy number remain incompletely understood. This review focuses on recent efforts to determine the nature of Rep protein complexes formed at the plasmid stability locus (STB) and at plasmid gene promoters, the identity of DNA sequence elements required for Rep protein association, and the mechanism by which the Rep proteins manage their dual roles of plasmid partitioning and plasmid gene repression.

Three-phase partitioning system with dimethyl carbonate as organic phase for partitioning of exopolysaccharides from Phellinus baumii.

In this study, a three-phase partitioning (TPP) system with dimethyl carbonate (DMC) as organic phase and sodium citrate (SC) as salt phase was used for partitioning of exopolysaccharide (EPS), namely, EPS-D, from fermentation broth of Phellinus baumii. Results showed that the maximum extraction yield (EY) of EPS-D was 71.02% under the following modified optimal conditions: DMC to fermentation broth ratio 0.5:1.0 (v/v), SC concentration 19% (w/v), temperature 30 °C, and pH 4.0. EPS-D had higher EY, carbohydrate, and uronic acid contents compared with the EPS, designated as EPS-T, obtained from the TPP system with t-butanol and ammonium sulfate. EPS-D and EPS-T had different chemical compositions and molecular weights; however, their preliminary chemical structures basically remained unchanged. Moreover, EPS-D exhibited stronger free radical-scavenging capability and total antioxidant capacity than EPS-T. Therefore, the TPP system with DMC as an alternative solvent for t-butanol has great potential for efficient partitioning of natural biomolecules.

Maintenance of the virulence plasmid in Shigella flexneri is influenced by Lon and two functional partitioning systems.

SummaryMembers of the genus Shigella carry a large plasmid, pINV, which is essential for virulence. In Shigella flexneri, pINV harbours three toxin‐antitoxin (TA) systems, CcdAB, GmvAT and VapBC that promote vertical transmission of the plasmid. Type II TA systems, such as those on pINV, consist of a toxic protein and protein antitoxin. Selective degradation of the antitoxin by proteases leads to the unopposed action of the toxin once genes encoding a TA system have been lost, such as following failure to inherit a plasmid harbouring a TA system. Here, we investigate the role of proteases in the function of the pINV TA systems and demonstrate that Lon, but not ClpP, is required for their activity during plasmid stability. This provides the first evidence that acetyltransferase family TA systems, such as GmvAT, can be regulated by Lon. Interestingly, S. flexneri pINV also harbours two putative partitioning systems, ParAB and StbAB. We show that both systems are functional for plasmid maintenance although their activity is masked by other systems on pINV. Using a model vector based on the pINV replicon, we observe temperature‐dependent differences between the two partitioning systems that contribute to our understanding of the maintenance of virulence in Shigella species.

Daytime atmospheric oxidation capacity in four Chinese megacities during the photochemically polluted season: a case study based on box model simulation

Abstract. Atmospheric oxidation capacity is the basis for converting freshly emitted substances into secondary products and is dominated by reactions involving hydroxyl radicals (OH) during daytime. In this study, we present in situ measurements of ROx radical (hydroxy OH, hydroperoxy HO2, and organic peroxy RO2) precursors and products; the measurements are carried out in four Chinese megacities (Beijing, Shanghai, Guangzhou, and Chongqing) during photochemically polluted seasons. The atmospheric oxidation capacity is evaluated using an observation-based model and radical chemistry precursor measurements as input. The radical budget analysis illustrates the importance of HONO and HCHO photolysis, which account for ∼50 % of the total primary radical sources. The radical propagation is efficient due to abundant NO in urban environments. Hence, the production rate of secondary pollutants, that is, ozone (and fine-particle precursors (H2SO4, HNO3, and extremely low volatility organic compounds, ELVOCs) is rapid, resulting in secondary air pollution. The ozone budget demonstrates its high production in urban areas; also, its rapid transport to downwind areas results in rapid increase in local ozone concentrations. The O3–NOx–VOC (volatile organic compound) sensitivity tests show that ozone production is VOC-limited and that alkenes and aromatics should be mitigated first for ozone pollution control in the four studied megacities. In contrast, NOx emission control (that is, a decrease in NOx) leads to more severe ozone pollution. With respect to fine-particle pollution, the role of the HNO3–NO3 partitioning system is investigated using a thermal dynamic model (ISORROPIA 2). Under high relative humidity (RH) and ammonia-rich conditions, nitric acid converts into nitrates. This study highlights the efficient radical chemistry that maintains the atmospheric oxidation capacity in Chinese megacities and results in secondary pollution characterized by ozone and fine particles.

Accommodation- versus supply-dominated systems for sediment partitioning to deep water

Accommodation- versus supply-dominated systems for sediment partitioning to deep water

Partial characterization of Bacillus pumilus catalase partitioned in poly(ethylene glycol)/sodium sulfate aqueous two-phase systems

Aqueous two-phase partitioning system (ATPS) was used to extract and purify catalase from Bacillus pumilus. The system parameters for effective purification of catalase were optimized. The best catalase recovery (123%) with a 4.6-fold purification was obtained in the bottom phase of ATPS including the mixture of 15% (w/w) PEG4000, 10% (w/w) Na2SO4 and 3% (w/w) NaCl at pH 5.0. The purified enzyme was characterized regarding its activity and stability. The highest enzyme activity was observed at pH 7.0 and 37 °C on hydrogen peroxide. The enzyme was quite stable at temperatures between 30 and 55 °C and a pH range of 7.0–9.0. The Km and Vmax values were determined from Lineweaver–Burk plot as 11 mM and 1667 µmole ml−1 min−1, respectively. Overall, it can be said that ATPS is a rapid, reasonable, straightforward and cost-effective process for catalase purification in comparison to the chromatographic methods.

Factores de expansión y sistema de partición de biomasa aérea para Pinus chiapensis (Martínez) Andresen

En el presente estudio se desarrollaron factores de expansión para biomasa constante y variable, además de un sistema de partición de biomasa aérea en plantaciones forestales comerciales de Pinus chiapensis. Mediante un muestreo destructivo de 35 árboles, se obtuvo el peso fresco de fuste, ramas y follaje en el campo y se tomaron muestras para determinar su peso seco. La relación del peso seco y fresco se empleó para convertir el peso freso en biomasa. A partir de una proporción directa del volumen total del fuste multiplicada por un factor de expansión de biomasa constante se estimó la biomasa aérea. El factor de expansión de biomasa variable se determinó con base en el cociente del modelo de biomasa aérea total y del volumen total del fuste. El sistema de partición de biomasa aérea se ajustó como una función directa de la biomasa y un factor de partición, que define la proporción de la biomasa por componentes. El valor del factor de expansión de biomasa constante reveló que por cada metro cúbico existen 709 kg de biomasa. El sistema de partición de biomasa aérea indicó una distribución de biomasa mayor en el fuste con 69 %, de ramas con 21 % y de follaje con 10 %. La aplicación de los factores de expansión de biomasa y sistema de partición de biomasa aérea permiten calcular la biomasa aérea total y por componentes a partir del volumen total del fuste de los árboles medidos en los inventarios forestales.

Characteristics and trend analysis of the relationship between land surface temperature and nighttime light intensity levels over China

Nighttime light (NTL) imagery, as an excellent data source for monitoring urban development and human activity, has been used in research concerning land surface thermal environment. However, previous studies have only taken NTL data as a measure of urbanization degree or to obtain intermediate products for LST studies, such as urban impervious surface area and building density. Few studies have systematically analyzed the spatial and temporal variations of different light levels and surface temperatures. In this study, a LST–NTL rank correlation model was constructed based on MOD11C3 and DMSP/OLS data to analyze the characteristics and trends of the relationship between LST and NTL, during both daytime and nighttime over China in 2012. The findings revealed a strong positive correlation between NTL level and LST, with the peak correlation (R2 > 0.85) observed during July–September, which indicated that, with the increase of the light intensity, the LST has an overall upward trend. The trend was relatively more stable during nighttime (variation range of R2 was 0.3) than during daytime (variation range of R2 was 0.44). Moreover, it was greatly enhanced without considering NTL intensity saturation pixels in the NTL partition system, and was further improved after removing pixels from urban centers, which was particularly evident at nighttime. This provided evidence that NTL intensity can be a good indicator for the distribution of urban thermal environment, particularly outside the urban centers.

Environmental Sorption Behavior of Ionic and Ionizable Organic Chemicals.

Traditionally our tools for environmental risk assessment of organic chemicals have been developed for neutral chemicals. However, many commercial chemicals are ionic or ionizable and require different tools and approaches for their assessment. In recent years this task starts to obtain increasing attention but our understanding for their environmental fate is still far behind that for neutral chemicals. This review first gives an overview on the principles that govern ionic partitioning in environmental systems which are more complex than the simple partition processes of neutral chemicals. Second, a summary of our current knowledge on various topics such as bioaccumulation, sorption in soils, and nonspecific-toxicity reveals that ionic species can actually be quite hydrophobic contrary to commonly held beliefs. Eventually, we discuss existing models for the quantitative prediction of organic ions' sorption in soils and biota. We have to assert that the available model tools are quite restricted in their application range compared to neutral chemicals which is due to the higher complexity of the various ionic sorption processes. In order to further advance our understanding more high-quality sorption data are needed with a focus on multivalent and zwitterionic ions in all partition systems as well as cations in biological matrices.

A PREDICTIVE FUZZY LOGIC MODEL TO BIMODAL WAVE PARTITIONING IN WELSH COASTLINE

Bimodal seas are usually characterised by the combination of swell and locally generated wind energy. Understanding the percentage of the swell component (SC) and the wind component (WC) partitioned from the energy content of a Wave System (WS) is important in coastal defense design and management. The South Wales and southwest England wave climate is mostly characterised by bimodal wave spectra because they are directly facing the North Atlantic Ocean. In this paper, we describe the application of fuzzy logic to develop an efficient wave partitioning system for bimodal wave energy separation that can be used to characterise the percentage of swell and wind waves in a measured sea state.

Unraveling the Initial Plant Hormone Signaling, Metabolic Mechanisms and Plant Defense Triggering the Endomycorrhizal Symbiosis Behavior.

Arbuscular mycorrhizal (AM) fungi establish probably one of the oldest mutualistic relationships with the roots of most plants on earth. The wide distribution of these fungi in almost all soil ecotypes and the broad range of host plant species demonstrate their strong plasticity to cope with various environmental conditions. AM fungi elaborate fine-tuned molecular interactions with plants that determine their spread within root cortical tissues. Interactions with endomycorrhizal fungi can bring various benefits to plants, such as improved nutritional status, higher photosynthesis, protection against biotic and abiotic stresses based on regulation of many physiological processes which participate in promoting plant performances. In turn, host plants provide a specific habitat as physical support and a favorable metabolic frame, allowing uptake and assimilation of compounds required for the life cycle completion of these obligate biotrophic fungi. The search for formal and direct evidences of fungal energetic needs raised strong motivated projects since decades, but the impossibility to produce AM fungi under axenic conditions remains a deep enigma and still feeds numerous debates. Here, we review and discuss the initial favorable and non-favorable metabolic plant context that may fate the mycorrhizal behavior, with a focus on hormone interplays and their links with mitochondrial respiration, carbon partitioning and plant defense system, structured according to the action of phosphorus as a main limiting factor for mycorrhizal symbiosis. Then, we provide with models and discuss their significances to propose metabolic targets that could allow to develop innovations for the production and application of AM fungal inocula.

ILP models for the allocation of recurrent workloads upon heterogeneous multiprocessors

The problem of partitioning systems of independent constrained-deadline sporadic tasks upon heterogeneous multiprocessor platforms is considered. Several different integer linear program (ILP) formulations of this problem, offering different trade-offs between effectiveness (as quantified by speedup bound) and running time efficiency, are presented. One of the formulations is leveraged to improve the best speedup guarantee known for a polynomial-time partitioning algorithm, from 12.9 to 7.83. Extensive computational results on synthetically generated instances are also provided to establish the effectiveness of the ILP formulations.

Entropy Accumulation With Improved Second-Order Term

The entropy accumulation theorem states that the smooth min-entropy of an $n$-partite system $A = (A_1, \ldots, A_n)$ is lower-bounded by the sum of the von Neumann entropies of suitably chosen conditional states up to corrections that are sublinear in $n$. This theorem is particularly suited to proving the security of quantum cryptographic protocols, and in particular so-called device-independent protocols for randomness expansion and key distribution, where the devices can be built and preprogrammed by a malicious supplier. However, while the bounds provided by this theorem are optimal in the first order, the second-order term is bounded more crudely, in such a way that the bounds deteriorate significantly when the theorem is applied directly to protocols where parameter estimation is done by sampling a small fraction of the positions, as is done in most QKD protocols. The objective of this paper is to improve this second-order sublinear term and remedy this problem. On the way, we prove various bounds on the divergence variance, which might be of independent interest.

Cooperative DNA Binding of the Plasmid Partitioning Protein TubR from the Bacillus cereus pXO1 Plasmid

Tubulin/FtsZ-like GTPase TubZ is responsible for maintaining the stability of pXO1-like plasmids in virulent Bacilli. TubZ forms a filament in a GTP-dependent manner, and like other partitioning systems of low-copy-number plasmids, it requires the centromere-binding protein TubR that connects the plasmid to the TubZ filament. Systems regulating TubZ partitioning have been identified in Clostridium prophages as well as virulent Bacillus species, in which TubZ facilitates partitioning by binding and towing the segrosome: the nucleoprotein complex composed of TubR and the centromere. However, the molecular mechanisms of segrosome assembly and the transient on–off interactions between the segrosome and the TubZ filament remain poorly understood. Here, we determined the crystal structure of TubR from Bacillus cereus at 2.0-Å resolution and investigated the DNA-binding ability of TubR using hydroxyl radical footprinting and electrophoretic mobility shift assays. The TubR dimer possesses 2-fold symmetry and binds to a 15-bp palindromic consensus sequence in the tubRZ promoter region. Continuous TubR-binding sites overlap each other, which enables efficient binding of TubR in a cooperative manner. Interestingly, the segrosome adopts an extended DNA–protein filament structure and likely gains conformational flexibility by introducing non-consensus residues into the palindromes in an asymmetric manner. Together, our experimental results and structural model indicate that the unique centromere recognition mechanism of TubR allows transient complex formation between the segrosome and the dynamic polymer of TubZ.

Host Range and Genetic Plasticity Explain the Coexistence of Integrative and Extrachromosomal Mobile Genetic Elements

Self-transmissible mobile genetic elements drive horizontal gene transfer between prokaryotes. Some of these elements integrate in the chromosome, whereas others replicate autonomously as plasmids. Recent works showed the existence of few differences, and occasional interconversion, between the two types of elements. Here, we enquired on why evolutionary processes have maintained the two types of mobile genetic elements by comparing integrative and conjugative elements (ICE) with extrachromosomal ones (conjugative plasmids) of the highly abundant MPFT conjugative type. We observed that plasmids encode more replicases, partition systems, and antibiotic resistance genes, whereas ICEs encode more integrases and metabolism-associated genes. ICEs and plasmids have similar average sizes, but plasmids are much more variable, have more DNA repeats, and exchange genes more frequently. On the other hand, we found that ICEs are more frequently transferred between distant taxa. We propose a model where the different genetic plasticity and amplitude of host range between elements explain the co-occurrence of integrative and extrachromosomal elements in microbial populations. In particular, the conversion from ICE to plasmid allows ICE to be more plastic, while the conversion from plasmid to ICE allows the expansion of the element's host range.