bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Hydrocarbon Recovery in Sliding Sleeve Completions Utilizing Diverters in the Wattenberg Field
Authors: Fry Jessica , Roach Erik , Kreyche Brett , Yenne Travis , Geoffrey Gullickson , Jespersen Matt
Published: January 2016

The use of sliding sleeve completions has been widely recognized as an efficient and effective means of completing horizontal laterals in unconventional reservoirs for several years. Recently, the focus shifted to optimizing stage spacing and number of stages per lateral. Even with such optimization the entire lateral was not effectively stimulated and drained. In this 15-well pad pilot study, we focused not only on optimizing the design but also on achieving uniform drainage along the lateral.

A treatment design using biodegradable diverters to split each stage into two proppant cycles was recommended. The diverter was used on 5 of the 14 wells completed. Total proppant and fluid volumes, as well as proppant and fluid types, were the same on conventionally-treated and diverter-treated wells. Average treating rates and operation procedures were also similar over the entire study group. After stimulation, the wells were turned on with identical chokes and produced similarly. Daily oil, gas, and water rates were monitored over eight months and compared.

Production was normalized on a cumulative barrel of oil equivalent (BOE) per foot of lateral basis. Results showed the diverter-treated wells produced 28% more than the conventionally-treated wells at eight months, with the margin increasing. Although all wells were completed on the same pad, at the subsurface level they covered over two miles of structurally variable formation. A multivariate analysis incorporating subsurface, drilling, completion, and production properties was also conducted to determine the most important parameters contributing to hydrocarbon recovery.

This study shows that diverters can be incorporated in sliding sleeve completions to lower the total cost per BOE and increase hydrocarbon recovery. This diverter design and technology continues to be implemented in projects with success and positive impacts on production.
Remote Imaging of Proppants in Hydraulic Fracture Networks Using Electromagnetic Methods: Results of Small-Scale Field Experiments
Authors: LaBrecque Douglas , Brigham Russell , Denison Jessica , Murdoch Lawrence , Slack William , Liu Qing Huo , Fang Yuan , Dai Junwen , Hu Yunyun , Yu Zhiru , Kleinhammes Alfred , Doyle Patrick , Wu Yue , Ahmadian Mohsen
Published: January 2016

The goal of this project is to develop techniques for monitoring hydraulic fractures in reservoirs by injecting electrically conductive, dielectric, or magnetically permeable proppants. The contrasts between the properties of the proppants and the subsurface provided the basis for imaging using geophysical methods. The initial experiments focused on a series of small, shallow fractures; however, the goal of the project is to develop methods applicable to oil-field fractures.

The project began by screening different proppant types using laboratory and numerical analyses that have been ongoing by researchers at the Advanced Energy Consortium (AEC). This work identified Loresco coke breeze and steel shot as materials that could create significant electrical or magnetic contrasts with most geological formations. These proppants were tested by creating hydraulic fractures in a shallow field setting consisting of highly weathered residual saprolite near Clemson University in western South Carolina. Six hydraulic fractures were created in highly monitored cells by injecting the contrasting proppants at a depth of approximately 1.5 m. This created sub-horizontal fractures filled with proppant approximately 10 mm thick and extending 3 to 5 m in maximum dimension.

Each cell had a dense array of electrodes and magnetic sensors on the surface, as well as four shallow vertical electrode arrays that were used to obtain data before and after hydraulic fracturing. Net vertical displacement, cores and trenching were used to characterize the fracture geometries.

Hydraulic fracture geometries were estimated by inverting pre- and post-injection geophysical data using various codes. Data from cores and excavation show that the hydraulic fractures formed a saucer-shape with a preferred propagation in the horizontal direction. The geophysical inversions generated images with remarkably similar form, size, and location to the ground truth from direct observation. Displacement and tilt data appear promising as a constraint on fracture geometry.
Interwell Hydraulic Fracture Interaction Between Multistage Stimulated Wells and a Multi Zone Slant Open Hole Observation Well Placed in the Canadian Horn River Basin
Authors: Pyecroft James , Lehmann Jurgen , Petr Christopher , Lypkie Kevin , Purdy Ivan , Zafar Hammad , Hiller Chelsey , Meeks David
Published: January 2016

This paper presents well construction details and pressure responses for a slant well in a dry gas shale resource in northern British Columbia, Canada. We will present the drilling and completions plan for a Multi-Stage Hydraulic Fracturing (MSHF) campaign on a ten well half pad including consequences of an aggressive fluid environment. Horn River shale gas development involves Multi-well MSHF horizontal wells from a single surface pad location. The wells are treated sequentially from toe to heel of the horizontal section, alternating between wells. Strategic placement of an Open Hole (OH) slant well equipped with slotted liner, tubing, and pressure data recorders will be presented. Pressure responses during the MSHF campaign will be presented and reviewed against calibrated closure pressure data from Diagnostic Fracture Injection Test (DFIT) data and end of job instantaneous shut-in pressures (ISIP).

The initial concept of drilling an OH well placed between MSHF wells was to evaluate the fracture system between stimulated wells and to test whether an unstimulated open hole well placed between stimulated wells can economically produce gas. Other objectives were to provide an Oil Based drilling Mud (OBM) free wellbore that would enable water-based imaging logs. Water-based logs have enhanced ability to identify and map natural fractures. Initial logs would evaluate the natural fractures and subsequent post-completion logs would evaluate the hydraulic fracture transiting the shale resource rock to the OH well. Knowledge of how pre-existing natural fracture networks react to the hydraulic fracture process along with pressure response data recorded from all wells on the pad would be used to provide geoscientists and engineers the means to optimize stimulation programs for horizontal wells and wellbore placement within the various resource reservoirs in the Horn River Basin.

This paper will discuss the compromises that were made to the initial conceptual model that maximized learnings from the slant OH wellbore, and how the well was unexpectedly lost. Pressure interference data for future hydraulic fracturing models will be provided along with methods to describe how hydraulic fractures from nearby wells transect a well and interact with various reservoirs exposed within the OH segment of a slant wellbore.
Determining the Effectiveness of Isolation Techniques Using Completion Diagnostics and Production Analysis
Authors: Senters C. W. , Snyder D. J. , Warren M. N. , Leonard R. S. , Woodroof R. A.
Published: January 2016

The development of unconventional resources in North America has led to the implementation of a variety of drilling and hydraulic fracturing techniques. This paper reviews completion diagnostic data from over 50 wells in the Anadarko and Williston Basins that were evaluated by a multidisciplinary team. Production analyses were conducted in conjunction with the diagnostic data to further qualify the effectiveness of different completion practices.

Stimulation diagnostics including proppant tracers, microseismic data, and permanently installed fiber optic sensors are available to assist with identifying fracture growth both within and outside of a targeted interval. Wells in this study will utilize proppant tracers for the evaluation of stage coverage and isolation effectiveness.

This paper specifically focuses on isolation techniques used during hydraulic fracturing of uncemented multistage horizontal wells, including swellable packers, and single and dual-element hydro-mechanical packers. Stimulation coverage and zonal containment for these isolation techniques were evaluated, and the results demonstrate how different isolation techniques can affect production.

This study shows how operating conditions may also affect the integrity of certain isolation techniques, as results for the most effective isolation techniques vary by basin. These operating variations, among others, are examined in this paper as a possible contributing factor for the loss of annular isolation and corresponding production decreases.

Isolation techniques are often implemented in drilling and completion programs with insufficient data or field trials. Most of these decisions are made based on perceived cost optimization rather than the overall completion effectiveness and performance of the well. This study is the first of its kind using a macroscopic analysis of completion diagnostics and production data over a large data set for the evaluation of isolation techniques.
Emperor Alexios III’s charters for the monastery of Hilandar and old Serbian writers
Authors: Todic Branislav
Published: January 2016

The focus of the study is set on two earliest surviving Greek charters in the
archive of the monastery of Hilandar on Mount Athos, a chrysobull and a
sigillion of emperor Alexios III Angelos, which are also the two most
important documents for the founding of the Serbian monastery. It discusses
the genesis of their texts, identifies their parts which might have been
borrowed from Saint Sava?s letters of request to emperor Alexios, as well as
the reception of the charters in the work of two 13th-century Serbian
writers, Domentijan and Teodosije.
An attempt of reconstruction of the collection of manuscripts of Devic monastery
Authors: Puzovic Ljiljana
Published: January 2016

The Serbian monastery Devic was built in 1434, in Drenica, a hilly region
where Kosovo and Metohija meet, and where St. Joannicius of Devic lived his
ascetic life, passed away and was buried. This great Serbian hermit, under
the patronage of Despot Djuradj Brankovic, built the original church dedicated
to the Presentation of the Virgin which gathered the whole monastic family.
Probably at the same time the first collection of manuscripts was built,
since the elementary liturgical books were needed for the regular liturgical
life. Different conserved manuscripts between the 16th and 19th century
attest transcription activities in the monastery, and, at the same time,
confirm that Devic Monastery was highly estimated among the Orthodox
Christians. First information about the literary fund of the monastery
originate in the mid-19th century when many researchers and antique lovers
visited the monastery. Testimonies about the scope and content of the Devic
collection of manuscripts are quite contradictory, however we are going to
try to determine in this paper which manuscripts were undoubtedly in the
collection with particular attention to the ones written in the monastery.
Despite very poor conditions this collection survived until the 20th century.
For safety reasons one part of the collection, which was transferred in the
National Library of Serbia, got destroyed during the bombing in April 1941.
The rest, which was held in the monastery, was burnt down, including the
temple church and the whole monastery complex, by the Albanian Fascists. What
remained from the former collection were just a few copies of books which
were taken out of the Devic before 1941. The monastery continues to exist
till the present day, despite vandalization in 2004.
Milutin Bojic’s letters to Milan Grol sent from Corfu 1916-1917.
Authors: Jovanovic Miroslav
Published: January 2016

The Archive of the Serbian Academy of Sciences and Arts in Belgrade holds
three letters that the young writer Milutin Bojic (1892-1917) sent to
dramaturge and politician Milan Grol (1876-1952). Bojic wrote to Grol from
the island of Corfu, where, together with the Serbian government and the
army, he was spending his days in exile. Bojic had a great desire to continue
his education and thus to contribute to the Serbian people and the state.
These letters are very important historical sources about the life of a young
poet who has famously described the suffering of Serbian Army in World War I
in his Ode to a Blue Sea Tomb.
Implementation of the forced answering option within online surveys: Do higher item response rates come at the expense of participation and answer quality?
Authors: Décieux Jean , Mergener Alexandra , Neufang Kristina , Sischka Philipp
Published: January 2016

Online surveys have become a popular method for data gathering for many
reasons, including low costs and the ability to collect data rapidly.
However, online data collection is often conducted without adequate
attention to implementation details. One example is the frequent use of the
forced answering option, which forces the respondent to answer each question
in order to proceed through the questionnaire. The avoidance of missing data
is often the idea behind the use of the forced answering option. However, we
suggest that the costs of a reactance effect in terms of quality reduction
and unit nonresponse may be high because respondents typically have
plausible reasons for not answering questions. The objective of the study
reported in this paper was to test the influence of forced answering on
dropout rates and data quality. The results show that requiring participants
answer every question increases dropout rates and decreases quality of
answers. Our findings suggest that the desire for a complete data set has to
be balanced against the consequences of reduced data quality.
Investigating response order effects in web surveys using eye tracking
Authors: Höhne Jan , Lenzner Timo
Published: January 2016

Response order effects are a well-known phenomenon that can occur when
answering survey questions with multiple response categories. Although
various theoretical explanations exist, the empirical evidence is
contradictory. Moreover, different scale types produce different effect
sizes. In the current study, we investigate the occurrence and causes of
response order effects in horizontal and vertical rating scales by means of
eye tracking. We conducted an experiment (n = 84) with two groups and varied
the scale direction so that the response scales either ran from agree to
disagree or vice versa. The results indicate that response order effects in
rating scales are relatively small and are more likely to occur in vertical
than in horizontal rating scales. Moreover, our eye-tracking data reveal that
respondents do not read all categories, nor do they pay equal attention to
all categories; these data support the survey satisficing theory of response
order effects (Krosnick, 1991).
Effect of inclination angle on the absorptance of a graphite-coated cold-rolled steel sheet irradiated by laser
Authors: Cook Felipe , Miró Leandro , Celentano Diego , Ramos-Grez Jorge
Published: January 2016

This work presents an experimental-numerical methodology aimed at deriving the relation between absorptance and incident angle of a randomly polarized Yb fiber-laser beam applied to a graphite-coated stainless steel cold-rolled sheet. The absorptance values were obtained by minimizing the error between temperature evolution measurements at various locations of the irradiated sheet and the corresponding finite element predictions. The absorptance was found to increase from 0.66 to 0.71 in the region between 0° and 10°, to return to the original value between 10° and 20°, to remain relatively constant between 20° and 50°, and then to drop sharply between 50° and 80° finishing at 0.44. Furthermore, the consequences of these results in the laser bending process are analyzed.
Pediatric intracranial gunshot wounds: the Memphis experience
Authors: DeCuypere Michael , Muhlbauer Michael S. , Boop Frederick A. , Klimo Paul
Published: January 2016

OBJECTIVE

Penetrating brain injury in civilians is much less common than blunt brain injury but is more severe overall. Gunshot wounds (GSWs) cause high morbidity and mortality related to penetrating brain injury; however, there are few reports on the management and outcome of intracranial GSWs in children. The goals of this study were to identify clinical and radiological factors predictive for death in children and to externally validate a recently proposed pediatric prognostic scale.

METHODS

The authors conducted a retrospective review of penetrating, isolated GSWs sustained in children whose ages ranged from birth to 18 years and who were treated at 2 major metropolitan Level 1 trauma centers from 1996 through 2013. Several standard clinical, laboratory, and radiological factors were analyzed for their ability to predict death in these patients. The authors then applied the St. Louis Scale for Pediatric Gunshot Wounds to the Head, a scoring algorithm that was designed to provide rapid prognostic information for emergency management decisions. The scale's sensitivity, specificity, and positive and negative predictability were determined, with death as the primary outcome.

RESULTS

Seventy-one children (57 male, 14 female) had a mean age of 14 years (range 19 months to 18 years). Overall mortality among these children was 47.9%, with 81% of survivors attaining a favorable clinical outcome (Glasgow Outcome Scale score ≥ 4). A number of predictors of mortality were identified (all p < 0.05): 1) bilateral fixed pupils; 2) deep nuclear injury; 3) transventricular projectile trajectory; 4) bihemispheric injury; 5) injury to ≥ 3 lobes; 6) systolic blood pressure < 100 mm Hg; 7) anemia (hematocrit < 30%); 8) Glasgow Coma Scale score ≤ 5; and 9) a blood base deficit < −5 mEq/L. Patient age, when converted to a categorical variable (0–9 or 10–18 years), was not predictive. Based on data from the 71 patients in this study, the positive predictive value of the St. Louis scale in predicting death (score ≥ 5) was 78%.

CONCLUSIONS

This series of pediatric cranial GSWs underscores the importance of the initial clinical exam and CT studies along with adequate resuscitation to make the appropriate management decision(s). Based on our population, the St. Louis Scale seems to be more useful as a predictor of who will survive than who will succumb to their injury.
Multiple-Scenario Unmanned Aerial System Control: A Systems Engineering Approach and Review of Existing Control Methods
Authors: Eaton Christopher , Chong Edwin , Maciejewski Anthony
Published: January 2016

The use of unmanned aerial systems (UASs) in both the public and military environments is predicted to grow significantly. As the demand for UASs grows, the availability of more robust and capable vehicles that can perform multiple mission types will be needed. In the public sector, the demand will grow for UASs to be used for agriculture, forestry, and search and rescue missions. Militaries continue to demand more UAS capabilities for diverse operations around the world. Significant research has been performed and continues to progress in the areas of autonomous UAS control. A majority of the work focuses on subsets of UAS control: path planning, autonomy, small UAS controls, and sensors. Minimal work exists on a system-level problem of multiple-scenario UAS control for integrated systems. This paper provides a high-level modular system architecture definition that is modifiable across platform types and mission requirements. A review of the current research and employment of UAS capabilities is provided to evaluate the state of the capabilities required to enable the proposed architecture.
Effects of Antioxidants in Human Cancers: Differential Effects on Non-Coding Intronic RNA Expression
Authors: Menon Shreya , Lu Chunxia , Menon Rajasree , Schwartz Jessica , Guan Yuanfang
Published: January 2016

The notion that dietary antioxidants can help fight cancer is popular. However, the mechanism(s) behind the effect of antioxidants in cancer is still unclear. Previous studies indicate that supplements can influence gene expression; however, all of these studies were focused on the coding/exonic gene expression. Studies are now emerging to highlight critical functional roles for RNAs expressed from the non-coding regions. This project was designed to study the effect of antioxidant supplements on non-coding intronic RNA expression in human cancers. Vitamin E, N-Acetyl cysteine (NAC) and Sulforaphane are commonly used supplements to prevent diseases including cancers. We studied the effect of these antioxidant supplements on the non-coding intronic RNA expression using publicly available datasets from a mouse model for lung cancer and prostate cancer cell lines. Although high throughput polyA-enriched RNA-Seq data characterize spliced coding mRNA regions, recent studies reveal the expression of reads from the non-coding intronic regions. Our analyses indicate that cancer cells have higher expression of introns compared to that of normal cells and that treatment with antioxidant supplements reduces the increased expression of introns of several genes. However, we did find high expression of introns of multiple genes including many oncogenes in the supplement treated groups compared to that of the control; this effect was distinct depending on the cell type and the supplement studied. Using RT-PCRs, we validated the expression of introns of two oncogenes, DLK1 and LRG1, known to be key players in lung cancer progression, and demonstrate changed intronic expression with supplement treatment in cancer cells. With regard to the antioxidant system, supplements did not change the intronic RNAs for endogenous antioxidant enzymes except for a significant decrease in the expression of superoxide dismutase (SOD) intronic RNA. Concurrently, we also found that a prolonged (48 h) exposure to Vitamin C, Vitamin E and Green tea extract reduced the enzymatic activity of SOD in lung cancer cells. The results from this study reveal that the antioxidant supplements have a significant effect on the intronic RNA expression of many genes including cancer genes that are not directly linked to the body’s antioxidant system. It is important to study this novel effect of antioxidant supplements in detail as it may have a significant role in disease progression.
Variation Characteristics of Rainfall in the Pre-Flood Season of South China and Its Correlation with Sea Surface Temperature of Pacific
Authors: Yao Suxiang , Huang Qian , Zhao Chen
Published: January 2016

The characteristics of rainfall variation in the pre-flood season of South China (PFSSC) and its correlation with the sea surface temperature (SST) of the Pacific are studied in this paper. The results show that in the last 50 years, rainfall in PFSSC clearly has interannual and interdecadal oscillations, primarily in the 4a and 8a cycles. Interannual correlation analysis indicate that the rainfall in PFSSC displays a significantly negative correlation with the SST of the warm pool region in January–March and April–June. The interdecadal correlation analysis reveals that the rainfall in PFSSC is negatively correlated to the SST of the warm pool region, but has a significant positive interdecadal correlation with the Middle Eastern Pacific Ocean. For NINO1 + 2 and NINO3 regions, when the background ocean temperature is warm, the SST is significantly positively correlated to the rainfall in PFSSC; however, when the background ocean temperature is cold, there is no significant correlation between the two, even the correlation coefficients are negative. For the warm pool region, the SST demonstrates a significantly negative correlation to the rainfall in PFSSC, which is not dependent on the background SST. It is a remarkable fact that under the different SST backgrounds, the interannual variation of SST will bring different atmospheric response, and it is the reason that under the warm SST background, the correlation is more significant between the SST in tropical Pacific and the rainfall in PFSSC. Under the background of global warming, more attention should be given to study the rainfall in PFSSC and its correlation with the SST in the eastern tropical Pacific.
MIRO GTPases in Mitochondrial Transport, Homeostasis and Pathology
Authors: Tang Bor
Published: January 2016

The evolutionarily-conserved mitochondrial Rho (MIRO) small GTPase is a Ras superfamily member with three unique features. It has two GTPase domains instead of the one found in other small GTPases, and it also has two EF hand calcium binding domains, which allow Ca2+-dependent modulation of its activity and functions. Importantly, it is specifically associated with the mitochondria and via a hydrophobic transmembrane domain, rather than a lipid-based anchor more commonly found in other small GTPases. At the mitochondria, MIRO regulates mitochondrial homeostasis and turnover. In metazoans, MIRO regulates mitochondrial transport and organization at cellular extensions, such as axons, and, in some cases, intercellular transport of the organelle through tunneling nanotubes. Recent findings have revealed a myriad of molecules that are associated with MIRO, particularly the kinesin adaptor Milton/TRAK, mitofusin, PINK1 and Parkin, as well as the endoplasmic reticulum-mitochondria encounter structure (ERMES) complex. The mechanistic aspects of the roles of MIRO and its interactors in mitochondrial homeostasis and transport are gradually being revealed. On the other hand, MIRO is also increasingly associated with neurodegenerative diseases that have roots in mitochondrial dysfunction. In this review, I discuss what is currently known about the cellular physiology and pathophysiology of MIRO functions.
Constructor Graphs as Useful Tools for the Classification of Hydrogen Bonded Solids: The Case Study of the Cationic (Dimethylphosphoryl)methanaminium (dpmaH+) Tecton
Authors: Reiss Guido
Published: January 2016

The structural chemistry of a series of dpmaH (dpmaH = (dimethylphosphoryl)methanaminium) salts has been investigated using constructor graph representations to visualize structural dependencies, covering the majority of known dpmaH salts. It is shown that the structurally related α-aminomethylphosphinic acid can be integrated in the systematology of the dpmaH salts. Those dpmaH salts with counter anions that are weak hydrogen bond acceptors (ClO4−, SnCl62−, IrCl62−,I−) tend to form head-to-tail hydrogen bonded moieties purely consisting of dpmaH+ cations as the primarily structural motif. In structures with weak to very weak hydrogen bonds between the dpmaH+ cations and the counter anions, the anions fill the gaps in the structures. In salts with medium to strong hydrogen bond acceptor counter ions (Cl−, NO3−, PdCl42−), the predominant structural motif is a double head-to-tail hydrogen bonded (dpmaH+)2 dimer. These dimeric units form further NH···X hydrogen bonds to neighboring counter anions X, which results in one-dimensional and two-dimensional architectures.
Towards the Development of a Universal Expression for the Configurational Entropy of Mixing
Authors: Garcés Jorge
Published: January 2016

This work discusses the development of analytical expressions for the configurational entropy of different states of matter using a method based on the identification of the energy-independent complexes (clustering of atoms) in the system and the calculation of their corresponding probabilities. The example of short-range order (SRO) in Nb-H interstitial solid solution is used to illustrate the choice of the atomic complexes and their structural changes with H concentration, providing an alternative methodology to describe critical properties. The calculated critical composition of the miscibility gap is xc = 0.307, in remarkable agreement with the experimental value of xc ~ 0.31. The same methodology is applied to deduce the equation of state (EOS) of a hard sphere system. The EOS is suitable to describe the percolation thresholds and fulfills both the low and random close packing limits. The model, based on the partition of the space into Voronoi cells, can be applied to any off-lattice system, thus introducing the possibility of computing the configurational entropy of gases, liquids and glasses with the same level of accuracy.
A Robust Weighted Combination Forecasting Method Based on Forecast Model Filtering and Adaptive Variable Weight Determination
Authors: Li Lianhui , Mu Chunyang , Ding Shaohu , Wang Zheng , Mo Runyang , Song Yongfeng
Published: January 2016

Medium-and-long-term load forecasting plays an important role in energy policy implementation and electric department investment decision. Aiming to improve the robustness and accuracy of annual electric load forecasting, a robust weighted combination load forecasting method based on forecast model filtering and adaptive variable weight determination is proposed. Similar years of selection is carried out based on the similarity between the history year and the forecast year. The forecast models are filtered to select the better ones according to their comprehensive validity degrees. To determine the adaptive variable weight of the selected forecast models, the disturbance variable is introduced into Immune Algorithm-Particle Swarm Optimization (IA-PSO) and the adaptive adjustable strategy of particle search speed is established. Based on the forecast model weight determined by improved IA-PSO, the weighted combination forecast of annual electric load is obtained. The given case study illustrates the correctness and feasibility of the proposed method.
Role for the Unfolded Protein Response in Heart Disease and Cardiac Arrhythmias
Authors: Liu Man , Dudley Samuel
Published: January 2016

The unfolded protein response (UPR) has been extensively investigated in neurological diseases and diabetes, while its function in heart disease is less well understood. Activated UPR participates in multiple cardiac conditions and can either protect or impair heart function. Recently, the UPR has been found to play a role in arrhythmogenesis during human heart failure by affecting cardiac ion channels expression, and blocking UPR has an antiarrhythmic effect. This review will discuss the rationale for and challenges to targeting UPR in heart disease for treatment of arrhythmias.
Effect of Chromatin Structure on the Extent and Distribution of DNA Double Strand Breaks Produced by Ionizing Radiation; Comparative Study of hESC and Differentiated Cells Lines
Authors: Venkatesh Priyanka , Panyutin Irina , Remeeva Evgenia , Neumann Ronald , Panyutin Igor
Published: January 2016

Chromatin structure affects the extent of DNA damage and repair. Thus, it has been shown that heterochromatin is more protective against DNA double strand breaks (DSB) formation by ionizing radiation (IR); and that DNA DSB repair may proceed differently in hetero- and euchromatin regions. Human embryonic stem cells (hESC) have a more open chromatin structure than differentiated cells. Here, we study the effect of chromatin structure in hESC on initial DSB formation and subsequent DSB repair. DSB were scored by comet assay; and DSB repair was assessed by repair foci formation via 53BP1 antibody staining. We found that in hESC, heterochromatin is confined to distinct regions, while in differentiated cells it is distributed more evenly within the nuclei. The same dose of ionizing radiation produced considerably more DSB in hESC than in differentiated derivatives, normal human fibroblasts; and one cancer cell line. At the same time, the number of DNA repair foci were not statistically different among these cells. We showed that in hESC, DNA repair foci localized almost exclusively outside the heterochromatin regions. We also noticed that exposure to ionizing radiation resulted in an increase in heterochromatin marker H3K9me3 in cancer HT1080 cells, and to a lesser extent in IMR90 normal fibroblasts, but not in hESCs. These results demonstrate the importance of chromatin conformation for DNA protection and DNA damage repair; and indicate the difference of these processes in hESC.
The Two Defaults Scenario for Stressing Credit Portfolio Loss Distributions
Authors: Tasche Dirk
Published: January 2016

The impact of a stress scenario of default events on the loss distribution of a credit portfolio can be assessed by determining the loss distribution conditional on these events. While it is conceptually easy to estimate loss distributions conditional on default events by means of Monte Carlo simulation, it becomes impractical for two or more simultaneous defaults as then the conditioning event is extremely rare. We provide an analytical approach to the calculation of the conditional loss distribution for the CreditRisk + portfolio model with independent random loss given default distributions. The analytical solution for this case can be used to check the accuracy of an approximation to the conditional loss distribution whereby the unconditional model is run with stressed input probabilities of default (PDs). It turns out that this approximation is unbiased. Numerical examples, however, suggest that the approximation may be seriously inaccurate but that the inaccuracy leads to overestimation of tail losses and, hence, the approach errs on the conservative side.
In Silico Analysis of a Novel Plasmid from the Coral Pathogen Vibrio coralliilyticus Reveals Two Potential “Ecological Islands”
Authors: Wachter Jenny , Hill Stuart
Published: January 2016

As virulence often correlates with the presence of plasmid replicons in several Vibrio spp., this study investigated whether non-chromosomal DNA could be found in the coral pathogen, Vibrio coralliilyticus BAA-450. A circular plasmid, 26,631 bp in size, was identified. DNA sequence analysis indicated that the plasmid contained 30 open reading frames, six tRNA genes, 12 inverted repeats, three direct repeats and presented no continuous sequence identity to other replicons within the database. Consequently, these findings indicate that this is a novel, previously unidentified, plasmid. Two putative “ecological islands” were also identified and are predicted to encode for various factors that would facilitate growth and survival under different ecological conditions. In addition, two open reading frames may encode proteins that contribute to the pathogenicity of the organism. Functional cooperativity is also indicated between several plasmid- and chromosomally-encoded proteins, which, in a single instance, would allow a fully functioning nutrient uptake system to be established.
DNA Binding, Photonuclease Activity and Human Serum Albumin Interaction of a Water-Soluble Freebase Carboxyl Corrole
Authors: Na Ning , Zhao Da-Qiang , Li Heng , Jiang Nan , Wen Jin-Yan , Liu Hai-Yang
Published: January 2016

The DNA binding property of 5,10,15-Tris(4-carboxyphenyl) corrole (TCPC) was studied by UV-Visible, fluorescence and circular dichroism (CD) spectroscopic methods. TCPC can bind to ct-DNA via an outside binding mode with the binding constant of Kb = 1.05 × 105 M−1. TCPC also displayed good photonuclease activity, which involves singlet oxygen species (1O2). The binding constant between TCPC and human serum albumin (HSA) is KA = 2.24 × 105 M−1 with a simulated binding distance of 2.06 nm. The fluorescence quenching of HSA by TCPC followed a static quenching process. Site marker competitive displacement experiments indicated that warfarin site I is the main binding site. The secondary structure of HSA was changed upon interaction with TCPC, which was confirmed by UV-Visible and CD spectroscopy.
Individuals with Metabolically Healthy Overweight/Obesity Have Higher Fat Utilization than Metabolically Unhealthy Individuals
Authors: Pujia Arturo , Gazzaruso Carmine , Ferro Yvelise , Mazza Elisa , Maurotti Samantha , Russo Cristina , Lazzaro Veronica , Romeo Stefano , Montalcini Tiziana
Published: January 2016

The mechanisms underlying the change in phenotype from metabolically healthy to metabolically unhealthy obesity are still unclear. The aim of this study is to investigate whether a difference in fasting fat utilization exists between overweight/obese individuals with a favorable cardiovascular risk profile and those with Metabolic Syndrome and Type 2 diabetes. Furthermore, we sought to explore whether there is an association between fasting fat utilization and insulin resistance. In this cross-sectional study, 172 overweight/obese individuals underwent a nutritional assessment. Those with fasting glucose ≥126 mg/dL or antidiabetic treatment were considered to be diabetics. If at least three of the NCEP criteria were present, they had Metabolic Syndrome, while those with less criteria were considered to be healthy overweight/obese. An indirect calorimetry was performed to estimate Respiratory Quotient, an index of nutrient utilization. A lower Respiratory Quotient (i.e., higher fat utilization) was found in healthy overweight/obese individuals than in those with Metabolic Syndrome and Type 2 diabetes (0.85 ± 0.05; 0.87 ± 0.06; 0.88 ± 0.05 respectively, p = 0.04). The univariate and multivariable analysis showed a positive association between the Respiratory Quotient and HOMA-IR (slope in statistic (B) = 0.004; β = 0.42; p = 0.005; 95% Confidence interval = 0.001–0.006). In this study, we find, for the first time, that the fasting Respiratory Quotient is significantly lower (fat utilization is higher) in individuals who are metabolically healthy overweight/obese than in those with metabolically unhealthy obesity. In addition, we demonstrated the association between fat utilization and HOMA-IR, an insulin resistance index.
Greater Total Antioxidant Capacity from Diet and Supplements Is Associated with a Less Atherogenic Blood Profile in U.S. Adults
Authors: Kim Kijoon , Vance Terrence , Chun Ock
Published: January 2016

Evidence from epidemiologic studies has shown that total antioxidant capacity (TAC) in the diet might be inversely associated with stroke, heart failure, and inflammatory biomarkers. However, studies on the association of TAC from both diet and supplements with cardiovascular disease (CVD) risk factors in the U.S. population are lacking. This cross-sectional population-based study aimed to investigate the association of TAC with both diet and supplements with CVD risk factors among 4039 U.S. adults in National Health and Nutrition Examination Survey (NHANES) 2007–2012. TAC from both food sources and dietary supplements was estimated from two 24-h dietary recalls using the NHANES supplement ingredient database, United States Department of Agriculture (USDA) proanthocyanidin, flavonoid, and isoflavone databases. Top contributors to TAC were tea, antioxidant supplements, vegetable mixture, orange juice, berries, and wine. Antioxidant supplement users had 1.6 times higher TAC than non-users. Greater TAC was associated with reduced triglycerides (TG) (−1.39% change; 95% CI = −2.56 to −0.21), TG to high-density lipoprotein cholesterol (HDL-C) ratio (−2.03% change; 95% CI = −3.45 to −0.60), HDL-C (0.65% change; 95% CI = 0.07 to 1.23), insulin (−1.37% change; 95% CI = −2.64 to −0.09), homeostasis model assessment of insulin resistance (HOMA-IR) (−1.57% change; 95% CI = −3.02 to −0.09) and C-reactive protein (CRP) (−0.83% change; 95% CI = −1.29 to −0.38) after adjusting for potential confounders. There was no significant association between TAC and waist circumference, BMI, blood pressure, low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and fasting glucose. The findings of this study support the hypothesis that an antioxidant-rich diet and intake of supplements are beneficial to reduce CVD risk.
Effect of Glycemic Index of Breakfast on Energy Intake at Subsequent Meal among Healthy People: A Meta-Analysis
Authors: Sun Feng-Hua , Li Chunxiao , Zhang Yan-Jie , Wong Stephen , Wang Lin
Published: January 2016

Meals with low glycemic index (GI) may suppress short-term appetite and reduce subsequent food intake compared with high-GI meals. However, no meta-analysis has been conducted to synthesize the evidence. This meta-analytic study was conducted to assess the effect of high- and low-GI breakfast on subsequent short-term food intake. Trials were identified through MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled trials, and manual searches of bibliographies until May 2015. Randomized controlled and cross-over trials comparing the effect of low- with high-GI breakfast on subsequent energy intake among healthy people were included. Nine studies consisting of 11 trials met the inclusion criteria. Only one trial was classified with high methodological quality. A total of 183 participants were involved in the trials. The meta-analytic results revealed no difference in breakfast GI (high-GI vs. low-GI) on subsequent short-term energy intake. In conclusion, it seems that breakfast GI has no effect on short-term energy intake among healthy people. However, high quality studies are still warranted to provide more concrete evidence.
Development of a Vaccine against Escherichia coli Urinary Tract Infections
Authors: Mobley Harry , Alteri Christopher
Published: January 2016

Urinary tract infection (UTI) is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC). Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT) as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA), into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs) of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot be ruled out and must be investigated experimentally. We have demonstrated that antibodies bind to the surface of UPEC expressing the antigens. Sera from women with and without histories of UTI have been tested for antibody levels to vaccine antigens. Our results validate iron acquisition as a target for vaccination against UTI.
Subversion of Host Innate Immunity by Uropathogenic Escherichia coli
Authors: Olson Patrick , Hunstad David
Published: January 2016

Uropathogenic Escherichia coli (UPEC) cause the majority of community-onset urinary tract infections (UTI) and represent a major etiologic agent of healthcare-associated UTI. Introduction of UPEC into the mammalian urinary tract evokes a well-described inflammatory response, comprising pro-inflammatory cytokines and chemokines as well as cellular elements (neutrophils and macrophages). In human UTI, this inflammatory response contributes to symptomatology and provides means for diagnosis by standard clinical testing. Early in acute cystitis, as demonstrated in murine models, UPEC gains access to an intracellular niche that protects a population of replicating bacteria from arriving phagocytes. To ensure the establishment of this protected niche, UPEC employ multiple strategies to attenuate and delay the initiation of host inflammatory components, including epithelial secretion of chemoattractants. Recent work has also revealed novel mechanisms by which UPEC blunts neutrophil migration across infected uroepithelium. Taken together, these attributes distinguish UPEC from commensal and nonpathogenic E. coli strains. This review highlights the unique immune evasion and suppression strategies of this bacterial pathogen and offers directions for further study; molecular understanding of these mechanisms will inform the development of adjunctive, anti-virulence therapeutics for UTI.
Optimum Conditions for Microwave Assisted Extraction for Recovery of Phenolic Compounds and Antioxidant Capacity from Macadamia (Macadamia tetraphylla) Skin Waste Using Water
Authors: Dailey Adriana , Vuong Quan
Published: January 2016

This study aimed to develop optimal microwave assisted extraction conditions for recovery of phenolic compounds and antioxidant properties from the macadamia skin, an abundant waste source from the macadamia industry. Water, a safe, accessible, and inexpensive solvent, was used as the extraction solvent and Response Surface Methodology (RSM) was applied to design and analyse the conditions for microwave-assisted extraction (MAE). The results showed that RSM models were reliable for the prediction of extraction of phenolic compounds and antioxidant properties. Within the tested ranges, MAE radiation time and power, as well as the sample-to-solvent ratio, affected the extraction efficiency of phenolic compounds, flavonoids, proanthocyanidins, and antioxidant properties of the macadamia skin; however, the impact of these variables was varied. The optimal MAE conditions for maximum recovery of TPC, flavonoids, proanthocyanidins and antioxidant properties from the macadamia skin were MAE time of 4.5 min, power of 30% (360 W) and sample-to-water ratio of 5 g/100 mL. Under these conditions, an extract could be prepared with TPC of 45 mg/g, flavonoids of 29 mg RUE/g of dried macadamia skin.
Aerosol Optical Depth Retrieval over Bright Areas Using Landsat 8 OLI Images
Authors: Sun Lin , Wei Jing , Bilal Muhammad , Tian Xinpeng , Jia Chen , Guo Yamin , Mi Xueting
Published: January 2016

Conventional methods for Aerosol Optical Depth (AOD) retrieval are limited to areas with low reflectance such as water or vegetated areas because the satellite signals from the aerosols in these areas are more obvious than those in areas with higher reflectance such as urban and sandy areas. Land Surface Reflectance (LSR) is the key parameter that must be estimated accurately. Most current methods used to estimate AOD are applicable only in areas with low reflectance. It has historically been difficult to estimate the LSR for bright surfaces because of their complex structure and high reflectance. This paper provides a method for estimating LSR for AOD retrieval in bright areas, and the method is applied to AOD retrieval for Landsat 8 Operational Land Imager (OLI) images at 500 m spatial resolution. A LSR database was constructed with the MODerate-resolution Imaging Spectroradiometer (MODIS) surface reflectance product (MOD09A1), and this database was also used to estimate the LSR of Landsat 8 OLI images. The AOD retrieved from the Landsat 8 OLI images was validated using the AOD measurements from four AErosol RObotic NETwork (AERONET) stations located in areas with bright surfaces. The MODIS AOD product (MOD04) was also compared with the retrieved AOD. The results demonstrate that the AOD retrieved with the new algorithm is highly consistent with the AOD derived from ground measurements, and its precision is better than that of MOD04 AOD products over bright areas.