bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic Simulation of Polymer Injectivity in Field Tests
Authors: Lotfollahi Mohammad , Farajzadeh Rouhi , Delshad Mojdeh , Al-Abri Khalil , Wassing Bart M. , Mjeni Rifaat , Awan Kamran , Bedrikovetsky Pavel
Published: August 2015

Polymer flooding is one of the most widely used chemical enhanced oil recovery methods due to its simplicity and low cost. To achieve high oil recoveries, large quantities of polymer solution is often injected through a small wellbore. Sometimes, the economic success of the project is only feasible when injection rate is high for high viscosity solution. However, injection of viscous polymer solutions has been a concern for the field application of polymer flooding.

The pressure increase in polymer injectors can be attributed to (1) formation of an oil bank, (2) polymer rheology (shear-thickening behavior at near well-bore), and (3) plugging of the reservoir pores by insoluble polymer molecules or suspended particles in the water.

In this paper, we propose a new model to history match field injection rate/pressure data. The pertinent equations for deep-bed filtration and external cake build-up in radial coordinate were coupled to the viscoelastic polymer rheology to capture important mechanisms. We selected radial coordinate in order to minimize the velocity/shear rate errors due to gridblock size in Cartesian coordinate.

We used filtration theory and successfully history matched the field data. We performed systematic simulations and studied the impact of adsorption (retention), shear thickening, deep bed filtration, and external cake formation to explain the well injectivity behavior of polymer. The simulation results indicate that the gradual increase in bottomhole pressure during early times is attributed to the shear thickening rheology at high velocities experienced by viscoelastic HPAM polymers around the wellbore and the permeability reduction due to polymer adsorption and internal filtration of undissolved polymer. However, the linear impedance during external cake growth is responsible for the sharper increase in injection pressure at the later times.

The proposed model can be used to calculate the injectivity of the polymer injection wells, understand the contribution of different phenomena on the pressure rise in the wells, locate the plugging or damage that may be caused by polymer, and accordingly design the chemical stimulation if necessary.
Laboratory and Simulation Investigation of the Effect of Thermally Activated Polymer on Permeability Reduction in Highly Permeable Unconsolidated Sand
Authors: Fabbri C.. , Klimenko A.. , Jouenne S.. , Cordelier Ph.. , Morel D..
Published: August 2015

The in-situ behavior of a Thermally Activated Polymer (TAP) was investigated through laboratory work on a high permeability core (7.5 D) and was interpreted by refined simulation. The experiment, carried out in a 100% water saturated core, aimed at determining the adsorption of the non-activated TAP and the activated TAP Residual Resistance Factor (RRF). The experiment and simulation results led to three observations impacting economic evaluation of TAP/gel treatment.

Firstly, unswollen TAP adsorbed, even if the significant values measured (130 µg/g of rock) may be overestimated due to the nature of the sand or to the fact that no residual oil was present in the porous medium. Secondly, in such high permeable sand, the main mechanism for mobility control of the swollen TAP was found to be the viscosity increase of the TAP solution. Indeed, in such high permeability material, permeability reduction estimated after 8 Pore Volumes (PV) of chase water was low (1.3). Refined history matching of the chase water injection in TAP evidenced that the fingering of the chase water through the high viscosity TAP slug should be expected. Therefore, rate variations and a high volume of chase water are required to evaluate the permeability reduction generated by TAP, and not to overestimate it. Finally, the injection of a slug of TAP in a quarter of five spot pattern was simulated with core scale grid blocks. Sensitivities were performed to quantify the dilution of the TAP slug. Results confirmed that the adsorption of the non-activated product and the viscosity of the injected solution affect the TAP distribution. The authors believe that these three observations should be included in the design of TAP treatments, and more generally, for in-depth gel treatments.
Visualization and Distribution of Ions at Fluids/Rock Interfaces: Angstrom Scale Study
Authors: Cha D. K. , Alotaibi M. B. , Yousef A. A.
Published: August 2015

Smart water and low-salinity waterflooding showed encouraging results in carbonate and sandstone reservoirs, respectively, at lab and field scales. Adjusting the injection water salinity and/or composition in either secondary or tertiary mode can positively instigate chemical interactions between reservoir fluids and rock minerals for enhanced oil recovery,. Several macroscopic and traditional laboratory techniques including coreflooding, contact angle, surface charges, NMR, and IFT have been extensively used to understand reaction mechanisms and subsequently optimize the water flooding process.

It is quite challenging to understand the behavior of reservoir fluids and water ions with carbonate minerals at very fine microscopic levels. Advanced technologies are required to comprehend the in-situ interactions at dynamic and static conditions. Cryogenic high resolution transmission electron microscopy (Cryogenic-HRTEM) equipped with energy dispersive spectroscopy (EDS) are utilized in this study to image oil droplets and dissolved salt ions at their native environment. Furthermore, Super-X EDS system? is used simultaneously to image the compositional distribution of multiple elements and to provide elemental mapping of the structures in solution. The experiments have been conducted using two different methodologies involving cryogenic-SEM and cryogenic-TEM. In addition, different fluids as crude oil, seawater and smartwater are observed at interfaces.

Results from this study revealed for the first time the in-situ distribution of mono and divalent ions around crude oil droplets. The elemental maps were shown to be distinct across the fluids and oil droplet interfaces. In comparison to seawater, smartwater reacted differently with crude oil components, and as a result, the interfacial layer thickness determined to be approximately 20 angstroms. This study gives a new insight about the elements’ distribution and interfacial layer's characteristics at different oi/brine interfaces. In summary, the observation at interfaces especially with smart water can alter the carbonate rock wettability towards water-wet for better oil recovery.
Comparison of History-Matched Water Flood, Tertiary Polymer Flood Relative Permeabilities and Evidence of Hysteresis During Tertiary Polymer Flood in Very Viscous Oils
Authors: Fabbri C.. , de Loubens R.. , Skauge A.. , Ormehaug P. A. , Vik B.. , Bourgeois M.. , Morel D.. , Hamon G..
Published: August 2015

Polymer flooding in very viscous oil has been gaining interest since its efficiency has been field proven. Multiple laboratory investigations have evidenced that the incremental oil recovered by the tertiary process increases considerably the recovery reached thanks to water flooding. However, such tertiary injection is made all the more complex that it is preceded by unstable displacement of oil by water. Therefore a better understanding of the physics is needed, in order to better predict and optimize the viscous oil reserves associated with tertiary polymer flooding.

This work presents the interpretation of three similar tertiary polymer flood experiments carried out at the Centre for Integrated Petroleum Research (CIPR, Norway). Each experiment consisted in a water flood followed by a polymer flood. They involved the same Bentheimer outcrop sandstone, 2000 cP oil, 70 cP polymer solution, 2D slab geometry, but different slab lengths (2 slabs are 30cmx30cm, 1 slab is 30cmx90cm). Saturation evolution was monitored by X-ray. On the one hand, provided simple simulation assumptions, the three water floods under study could be history matched (production, pressure). Similar ratios between water and oil relative permeabilities were found, although the water flood relative permeabilities, matched with non Corey-type curves, reflected an important variability. On the other hand, the tertiary polymer floods were found challenging to match consistently. In particular, using classic history matching approaches, the history matching of the long slab experiment could not be reconciled with that of short slab experiments. Simulations were initialized with saturation maps obtained at the end of the water floods. None of the tested approaches enabled us to match consistently the short and long slab experiments together, unless a hysteresis model was implemented. Indeed, a memory effect was observed experimentally from the quantitative analysis of X-ray saturation maps and interpreted as a hysteresis phenomenon. This simple model, with two additional matching parameters, is then further validated by the comparison of 2D simulations with measured in situ saturations.
Impact of Back Produced Polymer on Tertiary Water Treatment Performances
Authors: Jacob Matthieu , Demangel Anne , Goldszalu Alexandre , Rambeau Odile , Jouenne Stéphane , Cordelier Philippe
Published: August 2015

Management of produced water containing back produced polymer (HPAM) is a real challenge since its limited biodegradability and its relatively high concentration in produced water (up to few hundreds of mg/L) make it difficult to discharge into surface water. The preferred option is to conduct Produced Water Re-Injection (PWRI). When PWRI requires stringent water specifications as low as 10 mg/L of dispersed hydrocarbon (HC), 2 mg/L of total suspended solids (TSS) and 5 µm particle cut size (d100), tertiary treatments become mandatory. It is, for example, the case for PWRI in matrix mode for unconsolidated and shallow sand reservoirs. The objective of this study was to better understand the impact of HPAM polymer on tertiary treatment with a focus on ceramic membrane performances in order to optimize the design of produced water treatment facilities.

Maturity assessment of these water treatment technologies highlighted numerous major risks in presence of polymer. A R&D plan was then conducted on labscale prototypes using synthetic Produced Water (PW) containing polymer.

The tests performed with low pore size membrane (< 1 µm) met the specifications but the polymer was retained by the membrane which caused severe fouling and thus low productivity. Inversely, with pore size larger than 1µm, the polymer went through the membrane which strongly enhanced the productivity. However, with such large pores, the specifications are not anymore guaranteed. Two strategies were then identified and tested: (i) combine coagulation and membrane filtration or (ii) combine oxidation and membrane filtration using low pore size membranes. The use of coagulant (FeCl3) was very effective to precipitate the polymer and improve filtration performances but the management of the waste stream containing tons of precipitated polymer turned into a major showstopper. Inversely, the use of oxidation as a pre-treatment breaks polymer chains that become small enough to go through the membranes which (i) strongly improves membrane performances and (ii) enables the polymer re-injection.

This combination was successfully tested in batch but also in continuous mode using commercial membranes. The performances were then compared with other type of tertiary treatment technologies such as media filter (sand and walnut). In the context of PWRI in matrix mode for unconsolidated sand reservoirs (or any case that would require such stringent water specifications), membrane technology combined with oxidation is today a promising option deserving qualification tests at a larger scale.
Advanced Forward Modelling as an Integrated Tool in Seismic Reservoir Monitoring
Authors: Hill David , Lowden Dominic , Sonika Sonika , Paydayesh Mehdi , Bulat Andrej , Truelove Leigh , Chahine Clark , Herrera Adrian Rodriguez
Published: August 2015

The history of closed-loop seismic reservoir monitoring (CL-SRM) dates back to early 2000's with the History Matching Using Time Lapse Seismic (HUTS) project; the authors noted at the time that the proposed forward modelling step was too costly (Gosselin 2003).

From 2003 the technologies used in the forward modelling step of the CL-SRM workflow have developed in line with the availability of computing resources. Three groups of methods are currently in common use: a) direct analytical transformation of reservoir properties to seismic properties, b) variations on well log based fluid-substitution and petro-physical modelling, and c) simulation-to-seismic modelling (Gjøystdal, 2007). Both a) and b) are typically 1D and neglect realistic noise, overburden and acquisition configuration effect, while c) models noise free seismic data attributes, incorporating overburden and acquisition configuration effects via ray-tracing, but still neglects realistic noise. In all three cases the modelling is largely confined to the reservoir interval. More recent advances in computer architecture have now enabled large-scale finite difference acoustic and elastic modelling.

In parallel, research increasingly indicated the 4D-response associated with production was not restricted to the reservoir, but radiates into the over-burden, side-burden, and under-burden driven by geomechanical effects. Consequently to robustly predict a 4D-response related to production, field-scale modelling has to fully describe the acoustic and elastic response to both reservoir and field-wide changes. This complex interaction incorporates the reservoir dynamics component - which encompasses fluid properties, fluid flow characteristics, field performance history and pressure distributions and profiles over time, and also the changes in stress induced by the pressure changes during production. It is the stress changes that induce strains and deformations not only within the reservoir but also around it. Understanding the complete reservoir dynamics is not possible from studying the individual geologic, reservoir simulation, and reservoir geomechanical models in isolation – it requires they be integrated into a full-field coupled Dynamic Integrated Earth Model (DIEM)
On the Road to 60% Oil Recovery by Implementing Miscible Hydrocarbon WAG in a North-African Field
Authors: Maffeis I.. , Mogensen K.. , Rinaudo M.. , De Simoni M.. , Scarfato F.. , Galli G.. , Tripaldi G.. , Belaid F.. , Hachelaf H..
Published: August 2015

A WAG injection project is foreseen in a North-African field, which was first brought on stream in 2004 with production coming from two separate hydrocarbon columns within the Upper and Middle TAG-I Triassic sandstone reservoirs. The crude oil is light (44°API) and develops multi-contact miscibility with its own solution gas. The current development strategy centers on gas injection as well as water injection for pressure maintenance. Recently, the maximum gas separation capacity was reached, and because the operator respects a zero-flaring policy, a key element of the development strategy involves active gas management which may influence a number of smaller satellite fields that also tie in to the same production facilities.

This paper describes efforts to further increase oil recovery in the considered field by means of miscible hydrocarbon gas injection implemented as a tapered WAG. We describe our monitoring plan which involves, among other things, systematic use of diagnostic plots to constrain and assist history matching of the field performance. Some gas breakthrough data indicate arrival of a methane bank ahead of the main gas front, which suggests that the multi-contact miscibility may not be entirely preserved due to dispersion effects. The pattern performance analysis is inspired by earlier gas injection projects and its main purpose is to enable the operator to benchmark patterns and make efficient use of the available injectant. Current gas utilization ratio is around 25–30 Mscf/stb for continuous gas flooding. It is estimated that full-field implementation of a tapered, miscible hydrocarbon WAG will lower the gas utilization ratio further and push the recovery factor towards 60%.
Esthetic Challenges in Rehabilitating the Anterior Maxilla: A Case Report
Authors: Miranda ME , Olivieri KA , Rigolin FJF , de Vasconcellos AA
Published: August 2015

The rehabilitation of an unesthetic smile in the anterior maxilla is always a clinical challenge, especially when an improper shape and size, old restorations, and unesthetic shading are present. In addition, an irregular gingival zenith contour in the anterior maxilla can affect the smile's harmony. Thus, detailed treatment planning is needed to define a functional and esthetic prosthetic rehabilitation. This study describes a clinical case in which a 55-year-old woman was rehabilitated using Digital Smile Design planning and full ceramic crowns (metal free) in the anterior zone of the maxilla and mandible. To normalize the gingival zenith, a dynamic compression technique was performed using provisional restorations to condition the gingival tissues and harmonize the proportional length of the anterior upper teeth.
Estimated Fresh Produce Shrink and Food Loss in U.S. Supermarkets
Authors: Buzby Jean , Bentley Jeanine , Padera Beth , Ammon Cara , Campuzano Jennifer
Published: August 2015

Data on fresh fruit and vegetable shrink in supermarkets is important to help understand where and how much shrink could potentially be reduced by supermarkets to increase their profitability. This study provides: (1) shrink estimates for 24 fresh fruits and 31 fresh vegetables in U.S. supermarkets in 2011 and 2012; and (2) retail-level food loss. For each covered commodity, supplier shipment data was aggregated from a sample of 2900 stores from one national and four regional supermarket retailers in the United States, and this sum was then compared with aggregated point-of-sale data from the same stores to estimate the amount of shrink by weight and shrink rates. The 2011–2012 average annual shrink rates for individual fresh vegetables varied from 2.2 percent for sweet corn to 62.9 percent for turnip greens and for individual fresh fruit ranged from 4.1 percent for bananas to 43.1 percent for papayas. When these shrink estimates were used in the Loss-Adjusted Food Availability data series, annual food loss for these commodities totaled 5.9 billion pounds of fresh fruit and 6.1 billion pounds of fresh vegetables. This study extends the literature by providing important information on where and how much shrink could potentially be reduced. Precise comparisons across studies are difficult. This information, combined with information on available and cost-effective technologies and practices, may help supermarkets target food loss reduction efforts though food loss will never be zero.
Antibody Conjugates: From Heterogeneous Populations to Defined Reagents
Authors: Dennler Patrick , Fischer Eliane , Schibli Roger
Published: August 2015

Monoclonal antibodies (mAbs) and their derivatives are currently the fastest growing class of therapeutics. Even if naked antibodies have proven their value as successful biopharmaceuticals, they suffer from some limitations. To overcome suboptimal therapeutic efficacy, immunoglobulins are conjugated with toxic payloads to form antibody drug conjugates (ADCs) and with chelating systems bearing therapeutic radioisotopes to form radioimmunoconjugates (RICs). Besides their therapeutic applications, antibody conjugates are also extensively used for many in vitro assays. A broad variety of methods to functionalize antibodies with various payloads are currently available. The decision as to which conjugation method to use strongly depends on the final purpose of the antibody conjugate. Classical conjugation via amino acid residues is still the most common method to produce antibody conjugates and is suitable for most in vitro applications. In recent years, however, it has become evident that antibody conjugates, which are generated via site-specific conjugation techniques, possess distinct advantages with regard to in vivo properties. Here, we give a comprehensive overview on existing and emerging strategies for the production of covalent and non-covalent antibody conjugates.
Cavity-Assisted Generation of Sustainable Macroscopic Entanglement of Ultracold Gases
Authors: Joshi Chaitanya , Larson Jonas
Published: August 2015

Prospects for reaching persistent entanglement between two spatially-separated atomic Bose–Einstein condensates are outlined. The system setup comprises two condensates loaded in an optical lattice, which, in return, is confined within a high-Q optical resonator. The system is driven by an external laser that illuminates the atoms, such that photons can scatter into the cavity. In the superradiant phase, a cavity field is established, and we show that the emerging cavity-mediated interactions between the two condensates is capable of entangling them despite photon losses. This macroscopic atomic entanglement is sustained throughout the time-evolution apart from occasions of sudden deaths/births. Using an auxiliary photon mode and coupling it to a collective quadrature of the two condensates, we demonstrate that the auxiliary mode’s squeezing is proportional to the atomic entanglement, and as such, it can serve as a probe field of the macroscopic entanglement.
A Novel Micro Pressurized Liquid Extraction Method for Rapid Sample Preparation of Polycyclic Aromatic Hydrocarbons in Various Solids
Authors: Frantz Jackson , Alkhateeb Fadi , Thurbide Kevin
Published: August 2015

The use of a novel micro pressurized liquid extraction (µPLE) method for the isolation of 16 priority pollutant polycyclic aromatic hydrocarbons (PAHs) from various solid samples is explored. The technique employs rapid heating in a single static extraction mode to remove analytes in a matter of seconds from 5–10 mg samples using only 125 µL of solvent. For example, results show that 30 s extractions with toluene at 200 °C produce respective PAH recovery ranges of 90%–130% and 88%–114% from samples of soil and smoked chicken. Comparatively, solids containing significant amounts of biochar were more challenging to extract from. For instance, when using a pure biochar sample matrix, recoveries for the 16 PAHs range from only 33%–66% after 60 s of extraction with toluene at 200 °C. Overall, these extraction results agree very well with those reported when using conventional methods on similar samples. Therefore, the findings indicate that µPLE can potentially provide an alternative sample preparation method for PAHs that is both very rapid and requires little solvent.
Evaluation of 5 μm Superficially Porous Particles for Capillary and Microfluidic LC Columns
Authors: Grinias James , Kennedy Robert
Published: August 2015

Large-size (4–5 µm) superficially porous particles yield lower plate heights (e.g., the minimal reduced plate height or hmin ≈ 1.5) than fully porous particles of a similar size when packed into large-bore columns. This property allows for better chromatographic performance without the higher pressures required for smaller particles. This study explores the use of such particles in microfluidic LC columns where materials and fitting pressure limits can constrain the size of particle used. The theoretically predicted performance improvements compared to fully porous particles were not demonstrated in capillary columns (with hmin ≈ 2 for both particle types), in agreement with previous studies that examined smaller superficially porous particles. Microfluidic columns were then compared to capillary columns. Capillary columns significantly outperformed microfluidic columns due to imperfections imposed by microfluidic channel asymmetry and world-to-chip connection at the optimal flow rate; however, superficially porous particles packed in microfluidic LC columns had flatter plate height versus flow rate curves indicating potential for better performance at high reduced velocities.
Mitochondrial Mechanisms in Septic Cardiomyopathy
Authors: Cimolai María , Alvarez Silvia , Bode Christoph , Bugger Heiko
Published: August 2015

Sepsis is the manifestation of the immune and inflammatory response to infection that may ultimately result in multi organ failure. Despite the therapeutic strategies that have been used up to now, sepsis and septic shock remain a leading cause of death in critically ill patients. Myocardial dysfunction is a well-described complication of severe sepsis, also referred to as septic cardiomyopathy, which may progress to right and left ventricular pump failure. Many substances and mechanisms seem to be involved in myocardial dysfunction in sepsis, including toxins, cytokines, nitric oxide, complement activation, apoptosis and energy metabolic derangements. Nevertheless, the precise underlying molecular mechanisms as well as their significance in the pathogenesis of septic cardiomyopathy remain incompletely understood. A well-investigated abnormality in septic cardiomyopathy is mitochondrial dysfunction, which likely contributes to cardiac dysfunction by causing myocardial energy depletion. A number of mechanisms have been proposed to cause mitochondrial dysfunction in septic cardiomyopathy, although it remains controversially discussed whether some mechanisms impair mitochondrial function or serve to restore mitochondrial function. The purpose of this review is to discuss mitochondrial mechanisms that may causally contribute to mitochondrial dysfunction and/or may represent adaptive responses to mitochondrial dysfunction in septic cardiomyopathy.
Renal Transcriptome Analysis of Programmed Hypertension Induced by Maternal Nutritional Insults
Authors: Tain You-Lin , Hsu Chien-Ning , Chan Julie , Huang Li-Tung
Published: August 2015

Maternal nutrition can affect development, leading to long-term effects on the health of offspring. The most common outcome is programmed hypertension. We examined whether alterations in renal transcriptome are responsible for generating programmed hypertension among four different models using next-generation RNA sequencing (NGS) technology. Pregnant Sprague-Dawley rats received 50% caloric restriction (CR), intraperitoneal injection of 45 mg/kg streptozotocin, 60% high-fructose (HF) diet, or 1% NaCl in drinking water to conduct CR, diabetes, HF, or high-salt models, respectively. All four models induced programmed hypertension in adult male offspring. We observed 16 shared genes in a two-week-old kidney among four different models. The identified differential expressed genes (DEGs) that are related to the regulation of blood pressure included Adrb3, Alb, Apoe, Calca, Kng1, Adm2, Guca2b, Hba2, Hba-a2, and Ppara. The peroxisome proliferator-activated receptor (PPAR) signaling pathway and glutathione metabolism pathway were shared by the CR, diabetes, and HF models. Conclusively, a variety of maternal nutritional insults induced the same phenotype—programmed hypertension with differential alterations of renal transcriptome in adult male offspring. The roles of DEGs identified by the NGS in this study deserve further clarification to develop ideal maternal dietary interventions and thus spare the next generations from the burden of hypertension.
The Involvement of Mutual Inhibition of ERK and mTOR in PLCγ1-Mediated MMP-13 Expression in Human Osteoarthritis Chondrocytes
Authors: Liu Zejun , Cai Heguo , Zheng Xinpeng , Zhang Bing , Xia Chun
Published: August 2015

The issue of whether ERK activation determines matrix synthesis or degradation in osteoarthritis (OA) pathogenesis currently remains controversial. Our previous study shows that PLCγ1 and mTOR are involved in the matrix metabolism of OA cartilage. Investigating the interplays of PLCγ1, mTOR and ERK in matrix degradation of OA will facilitate future attempts to manipulate ERK in OA prevention and therapy. Here, cultured human normal chondrocytes and OA chondrocytes were treated with different inhibitors or transfected with expression vectors, respectively. The levels of ERK, p-ERK, PLCγ1, p-PLCγ1, mTOR, p-mTOR and MMP-13 were then evaluated by Western blotting analysis. The results manifested that the expression level of ERK in human OA chondrocytes was lower than that in human normal articular chondrocytes, and the up-regulation of ERK could promote matrix synthesis, including the decrease in MMP-13 level and the increase in Aggrecan level in human OA chondrocytes. Furthermore, the PLCγ1/ERK axis and a mutual inhibition of mTOR and ERK were observed in human OA chondrocytes. Interestingly, activated ERK had no inhibitory effect on MMP-13 expression in PLCγ1-transformed OA chondrocytes. Combined with our previous study, the non-effective state of ERK activation by PLCγ1 on MMP-13 may be partly attributed to the inhibition of the PLCγ1/mTOR axis on the PLCγ1/ERK axis. Therefore, the study indicates that the mutual inhibition of ERK and mTOR is involved in PLCγ1-mediated MMP-13 expression in human OA chondrocytes, with important implication for the understanding of OA pathogenesis as well as for its prevention and therapy.
Conformational Motions and Functionally Key Residues for Vitamin B12 Transporter BtuCD–BtuF Revealed by Elastic Network Model with a Function-Related Internal Coordinate
Authors: Su Ji-Guo , Zhang Xiao , Zhao Shu-Xin , Li Xing-Yuan , Hou Yan-Xue , Wu Yi-Dong , Zhu Jian-Zhuo , An Hai-Long
Published: August 2015

BtuCD–BtuF from Escherichia coli is a binding protein-dependent adenosine triphosphate (ATP)-binding cassette (ABC) transporter system that uses the energy of ATP hydrolysis to transmit vitamin B12 across cellular membranes. Experimental studies have showed that during the transport cycle, the transporter undergoes conformational transitions between the “inward-facing” and “outward-facing” states, which results in the open–closed motions of the cytoplasmic gate of the transport channel. The opening–closing of the channel gate play critical roles for the function of the transporter, which enables the substrate vitamin B12 to be translocated into the cell. In the present work, the extent of opening of the cytoplasmic gate was chosen as a function-related internal coordinate. Then the mean-square fluctuation of the internal coordinate, as well as the cross-correlation between the displacement of the internal coordinate and the movement of each residue in the protein, were calculated based on the normal mode analysis of the elastic network model to analyze the function-related motions encoded in the structure of the system. In addition, the key residues important for the functional motions of the transporter were predicted by using a perturbation method. In order to facilitate the calculations, the internal coordinate was introduced as one of the axes of the coordinate space and the conventional Cartesian coordinate space was transformed into the internal/Cartesian space with linear approximation. All the calculations were carried out in this internal/Cartesian space. Our method can successfully identify the functional motions and key residues for the transporter BtuCD–BtuF, which are well consistent with the experimental observations.
Experimental and Theoretical Investigations on the Supermolecular Structure of Isoliquiritigenin and 6-O-α-D-Maltosyl-β-cyclodextrin Inclusion Complex
Authors: Li Bin , Liu Benguo , Li Jiaqi , Xiao Huizhi , Wang Junyi , Liang Guizhao
Published: August 2015

Isoliquiritigenin (ILTG) possesses many pharmacological properties. However, its poor solubility and stability in water hinders its wide applications. The solubility of bioactive compounds can often be enhanced through preparation and delivery of various cyclodextrin (CD) inclusion complexes. The 6-O-α-D-maltosyl-β-CD (G2-β-CD), as one of the newest developments of CDs, has high aqueous solubility and low toxicity, especially stable inclusion characteristics with bioactive compounds. In this work, we for the first time construct and characterize the supermolecular structure of ILTG/G2-β-CD by scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD). The solubility of ILTG in water at 25 °C rises from 0.003 to 0.717 mg/mL by the encapsulation with G2-β-CD. Our experimental observations on the presence of the ILTG/G2-β-CD inclusion complex are further supported by the ONIOM(our Own N-layer Integrated Orbital molecular Mechanics)-based QM/MM (Quantum Mechanics/Molecular Mechanics) calculations, typically substantiating these supermolecular characteristics, such as detailed structural assignments, preferred binding orientations, selectivity, solvent effects, interaction energies and forces of the ILTG/G2-β-CD inclusion complex. Our results have elucidated how ILTG interacts with G2-β-CD, demonstrating the primary host-guest interactions between ILTG and G2-β-CD, characterized by hydrogen bonds, hydrophobic interactions, electrostatic forces, and conformational effects, are favored for the formation of the ILTG/G2-β-CD inclusion.
Behavioral Symptoms after Breast Cancer Treatment: A Biobehavioral Approach
Authors: Fagundes Christopher , LeRoy Angie , Karuga Maryanne
Published: August 2015

Being diagnosed and treated for breast cancer is emotionally and physically challenging. Breast cancer is the most commonly diagnosed cancer and the second leading cause of death for women in the United States. Accordingly, women with a breast cancer history are the largest group of female cancer survivors. Psychological stress substantially augments adverse autonomic, endocrine, and immune discharge, including enhanced production of proinflammatory cytokines. Importantly, inflammation is a key biological mechanism underlying the symptom cluster of pain, depression, fatigue, and sleep disturbances; there is also good evidence that inflammation contributes to breast cancer recurrence. Stress may exert direct effects on psychological and physiological risk processes. In this review, we take a biobehavioral approach to understanding predictors and mechanisms underlying somatic symptoms in breast cancer survivors.
A Long-Range Directional Wake-Up Radio for Wireless Mobile Networks
Authors: Shih Wen-Chan , Jurdak Raja , Abbott David , Chou Pai , Chen Wen-Tsuen
Published: August 2015

This paper describes a long-range directional wake-up radio (LDWuR) for wireless mobile networks. In contrast to most wake-up radios (WuR) to date, which are short range, ours is applicable to long-range deployments. Existing studies achieve long distance by using modulation and coding schemes or by directional antennas, though the latter require exploring the direction of the transmitter. To address this issue, our LDWuR adopts both static and dynamic antennas, where the static ones are directional, while the dynamic ones are omnidirectional for beamforming. We present our LDWuR prototype and design principle. Simulation results show that our LDWuR and event-driven MAC protocol suppress the idle-listening of Wi-Fi stations in a wireless network, thereby enhancing the Wi-Fi power savings.
1,6- and 1,7-Regioisomers of Highly Soluble Amino-Substituted Perylene Tetracarboxylic Dianhydrides: Synthesis, Optical and Electrochemical Properties
Authors: Chen Kew-Yu , Chang Che-Wei , Tsai Hsing-Yang
Published: August 2015

1,6- and 1,7-regioisomers of diamino-substituted perylene tetracarboxylic dianhydrides (PTCDs) with different n-alkyl chain lengths (n = 6, 12 or 18) were synthesized and characterized by NMR spectroscopy and high-resolution mass spectrometry. These dyes are highly soluble in most organic solvents and even in nonpolar solvents, such as hexane. To the best of our knowledge, this is the first time the 1,6-diamino-substituted PTCDs (2a–2c) have been obtained in pure form. The regioisomers 1a–1c (1,7-) and 2a–2c (1,6-) exhibit significant differences in their optical characteristics. In addition to the longest wavelength absorption band at around 674 nm, 2a–2c exhibit another shoulder band at ca. 600 nm, and consequently, cover a large part of the visible region relative to those of 1a–1c. Upon excitation, 2a–2c also show larger dipole moment changes than those of 1a–1c; the dipole moments of all compounds have been estimated using Lippert–Mataga equation. Moreover, all the dyes show a unique charge transfer emission in the near-infrared region, of which the peak wavelengths exhibit strong solvatochromism. They all exhibit one irreversible one-electron oxidation and two quasi-reversible one-electron reductions in dichloromethane at modest potentials. Complementary density functional theory calculations performed on these chromophores are reported in order to rationalize their electronic structure and optical properties.
Treatment of Diabetic Gastroparesis by Complementary and Alternative Medicines
Authors: Liu Hao , Yu Bo , Zhang Meng , Liu Kun , Wang Fu-Chun , Gao Xin-Yan
Published: August 2015

Gastroparesis is a common gastrointestinal complication in diabetes, induced by hyperglycemia and characterized by delayed gastric emptying and upper abdominal symptoms, such asnausea, vomiting, early satiety, bloating and epigastric pain. Diabetic gastroparesis (DGP) affects life quality and glycemic control, and is a challenge to treat in both Western and Eastern medicine. Routine treatment in Western medicine includes gastric emptying promoted by prokinetic agents, gastric pacemaking, or surgery combined with lifetime hormono-therapy, all of which have unavoidable side effects and limitations, and are very expensive. Complementary and alternative medical treatments like acupuncture, moxibustion, and massage are becoming more and more attractive because of their effectiveness, fewer side effects, and reliable safety. This article aims to introduce representative methods of complementary and alternative medicine to treat DGP, which were searched in English through Pubmed and in Chinese through CNKI (China Knowledge Resource Integrated Database). Several lines of evidence demonstrated the effects of single or combined complementary alternative therapies on DGP outcomes; however, the mechanisms were rarely investigated. Randomized controlled trials are undoubtedly required in future studies.
Search for Antiprotozoal Activity in Herbal Medicinal Preparations; New Natural Leads against Neglected Tropical Diseases
Authors: Llurba-Montesino Núria , Kaiser Marcel , Brun Reto , Schmidt Thomas
Published: August 2015

Sleeping sickness, Chagas disease, Leishmaniasis, and Malaria are infectious diseases caused by unicellular eukaryotic parasites (“protozoans”). The three first mentioned are classified as Neglected Tropical Diseases (NTDs) by the World Health Organization and together threaten more than one billion lives worldwide. Due to the lack of research interest and the high increase of resistance against the existing treatments, the search for effective and safe new therapies is urgently required. In view of the large tradition of natural products as sources against infectious diseases [1,2], the aim of the present study is to investigate the potential of legally approved and marketed herbal medicinal products (HMPs) as antiprotozoal agents. Fifty-eight extracts from 53 HMPs on the German market were tested by a Multiple-Target-Screening (MTS) against parasites of the genera Leishmania, Trypanosoma, and Plasmodium. Sixteen HMPs showed in vitro activity against at least one of the pathogens (IC50 < 10 µg/mL). Six extracts from preparations of Salvia, Valeriana, Hypericum, Silybum, Arnica, and Curcuma exhibited high activity (IC50 < 2.5 µg/mL). They were analytically characterized by UHPLC/ESI-QqTOF-MSMS and the activity-guided fractionation of the extracts with the aim to isolate and identify the active compounds is in progress.
Dynamics of a Low-Dimensional Model for Short Pulse Mode Locking
Authors: Farnum Edward , Kutz J.
Published: August 2015

Emerging ultra-fast mode-locked lasers are now capable of generating pulses in the few to sub-femtosecond regime. Using recent theoretical innovations around the short pulse equation, we characterize the mode locking dynamics using a low-dimensional representation of the pulse parameters. The theory is formulated using a variational approach, since linearization of the exact solution is not tractable. The dominant dynamics can be characterized in a geometrical way using phase-plane analysis. Of note is our ability to determine the underlying bifurcations that occur due to changes in the fiber laser cavity parameters, including the onset of the multi-pulsing instability. The theory can aid in design principles for generating robust and highly-stable mode-locked pulses.
Interdiffusion and Spinodal Decomposition in Electrically Conducting Polymer Blends
Authors: Takala Antti , Takala Päivi , Seppälä Jukka , Levon Kalle
Published: August 2015

The impact of phase morphology in electrically conducting polymer composites has become essential for the efficiency of the various functional applications, in which the continuity of the electroactive paths in multicomponent systems is essential. For instance in bulk heterojunction organic solar cells, where the light-induced electron transfer through photon absorption creating excitons (electron-hole pairs), the control of diffusion of the spatially localized excitons and their dissociation at the interface and the effective collection of holes and electrons, all depend on the surface area, domain sizes, and connectivity in these organic semiconductor blends. We have used a model semiconductor polymer blend with defined miscibility to investigate the phase separation kinetics and the formation of connected pathways. Temperature jump experiments were applied from a miscible region of semiconducting poly(alkylthiophene) (PAT) blends with ethylenevinylacetate-elastomers (EVA) and the kinetics at the early stages of phase separation were evaluated in order to establish bicontinuous phase morphology via spinodal decomposition. The diffusion in the blend was followed by two methods: first during a miscible phase separating into two phases: from the measurement of the spinodal decomposition. Secondly the diffusion was measured by monitoring the interdiffusion of PAT film into the EVA film at elected temperatures and eventually compared the temperature dependent diffusion characteristics. With this first quantitative evaluation of the spinodal decomposition as well as the interdiffusion in conducting polymer blends, we show that a systematic control of the phase separation kinetics in a polymer blend with one of the components being electrically conducting polymer can be used to optimize the morphology.
Extrinsic Calibration of Camera Networks Using a Sphere
Authors: Guan Junzhi , Deboeverie Francis , Slembrouck Maarten , Van Haerenborgh Dirk , Van Cauwelaert Dimitri , Veelaert Peter , Philips Wilfried
Published: August 2015

In this paper, we propose a novel extrinsic calibration method for camera networks using a sphere as the calibration object. First of all, we propose an easy and accurate method to estimate the 3D positions of the sphere center w.r.t. the local camera coordinate system. Then, we propose to use orthogonal procrustes analysis to pairwise estimate the initial camera relative extrinsic parameters based on the aforementioned estimation of 3D positions. Finally, an optimization routine is applied to jointly refine the extrinsic parameters for all cameras. Compared to existing sphere-based 3D position estimators which need to trace and analyse the outline of the sphere projection in the image, the proposed method requires only very simple image processing: estimating the area and the center of mass of the sphere projection. Our results demonstrate that we can get a more accurate estimate of the extrinsic parameters compared to other sphere-based methods. While existing state-of-the-art calibration methods use point like features and epipolar geometry, the proposed method uses the sphere-based 3D position estimate. This results in simpler computations and a more flexible and accurate calibration method. Experimental results show that the proposed approach is accurate, robust, flexible and easy to use.
Cross-Excitation in Peripheral Sensory Ganglia Associated with Pain Transmission
Authors: Omoto Katsuhiro , Maruhama Kotaro , Terayama Ryuji , Yamamoto Yumiko , Matsushita Osamu , Sugimoto Tomosada , Oguma Keiji , Matsuka Yoshizo
Published: August 2015

Despite the absence of synaptic contacts, cross-excitation of neurons in sensory ganglia during signal transmission is considered to be chemically mediated and appears increased in chronic pain states. In this study, we modulated neurotransmitter release in sensory neurons by direct application of type A botulinum neurotoxin (BoNT/A) to sensory ganglia in an animal model of neuropathic pain and evaluated the effect of this treatment on nocifensive. Unilateral sciatic nerve entrapment (SNE) reduced the ipsilateral hindpaw withdrawal threshold to mechanical stimulation and reduced hindpaw withdrawal latency to thermal stimulation. Direct application of BoNT/A to the ipsilateral L4 dorsal root ganglion (DRG) was localized in the cell bodies of the DRG and reversed the SNE-induced decreases in withdrawal thresholds within 2 days of BoNT/A administration. Results from this study suggest that neurotransmitter release within sensory ganglia is involved in the regulation of pain-related signal transmission.
Phanerotoma libertinecida (Hymenoptera: Braconidae), a new species of parasitoid of Grapholita libertina (Lepidoptera: Tortricidae) associated with lingonberry (Ericaceae)
Authors: Goulet H. , Hillier N.K. , Dixon P.L. , Larson D.J.
Published: August 2015

Phanerotoma libertinecidanew species (Hymenoptera: Braconidae: Cheloninae) is described and put in context with the latest North American revision of the genus. The species has been reared repeatedly from Grapholita libertina Heinrich (Lepidoptera: Tortricidae), which is found on lingonberry (Vaccinium vitis-idaea var. minor Loddiges, Loddiges, and Loddiges (Ericaceae)). Its natural history is also described.
Simulants of malignant melanoma
Authors: Piérard Gérald E. , Piérard-Franchimont Claudine , Delvenne Philippe
Published: August 2015

During the recent period, dermoscopy has yielded improvement in the early disclosure of various atypical melanocytic neoplasms (AMN) of the skin. Beyond this clinical procedure, AMN histopathology remains mandatory for establishing their precise diagnosis. Of note, panels of experts in AMN merely report moderate agreement in various puzzling cases. Divergences in opinion and misdiagnosis are likely increased when histopathological criteria are not fine-tuned and when facing a diversity of AMN types. Furthermore, some AMN have been differently named in the literature including atypical Spitz tumor, metastasizing Spitz tumor, borderline and intermediate melanocytic tumor, malignant Spitz nevus, pigmented epithelioid melanocytoma or animal-type melanoma. Some acronyms have been further suggested such as MELTUMP (after melanocytic tumor of uncertain malignant potential) and STUMP (after Spitzoid melanocytic tumor of uncertain malignant potential). In this review, such AMN at the exclusion of cutaneous malignant melanoma (MM) variants, are grouped under the tentative broad heading skin melanocytoma. Such set of AMN frequently follows an indolent course, although they exhibit atypical and sometimes worrisome patterns or cytological atypia. Rare cases of skin melanocytomas progress to loco regional clusters of lesions (agminate melanocytomas), and even to regional lymph nodes. At times, the distinction between a skin melanocytoma and MM remains puzzling. However, multipronged immunohistochemistry and emerging molecular biology help profiling any malignancy risk if present.