bluuebunny/crossref_metadata_2025 huggingface dataset:
Bilinear Flow in Horizontal Wells in a Homogeneous Reservoir: Huntington Case Study
Authors: Feng Wei Cher , Nurafza Peyman , Al-Shamma Basil , Gringarten Alain
Published: May 2015

In the Huntington field, bilinear flow with a clear one-quarter unit slope in the pressure derivative has been observed during intermediate-times in horizontal well tests, instead of the usual linear flow with a half unit slope expected in a homogeneous reservoir. This paper investigates various analytical methods with numerical methods to explain this behaviour.

A number of plausible explanations of this pressure behavior were investigated in this study: rate history or production-time effects; transition between early and late time derivative radial flow stabilizations which could yield a quarter slope straight line on the derivative for specific combinations of horizontal and vertical permeabilities, well length and reservoir thickness; and geological conditions such as high-permeability streaks, the presence of shale barriers, and layering with varying permeability.

It was concluded from numerical simulations and geological evidence that the most likely explanation, which yields the best match with well test data, was uniform horizontal permeability and non-uniform vertical permeability increasing from the bottom to the top of the reservoir. This is consistent with the geology of the Huntington field, where the depositional sequence is dominated by high-density turbidity currents.

At each sedimentation pulse, heavier pebble/gravel lags were deposited first at the base of channels followed by finer particles which may have formed thin shale drapes. In addition, diagenesis might have led to cementation of pebble/gravel lags. The non-uniform and non-laterally extensive occurrence of the cemented pebble/gravel lags and thin shale drapes act as local baffles to vertical flow but not to horizontal flow resulting in bilinear flow behaviour in the reservoir. This paper offers a unique insight into an integrated effort at combining analytical, numerical well test models and geological evidence to explain the reservoir behavior observed in the Huntington field.
Importance of Fines in Smart Water Enhanced Oil Recovery (SmW-EOR) for Chalk Outcrops
Authors: Chakravarty Krishna Hara , Fosbøl Philip Loldrup , Thomsen Kaj
Published: May 2015

In SmW-EOR it is generally believed that precipitation of brines must be avoided since it can have a negative impact on the SmW sweep efficiency. But substitution of Mg2+ by Ca2+ on calcite surfaces (a well-accepted phenomenon) can change the brine combination and enhance the possibility of fine formation at speciation. Considering this phenomenon we analyze the possibility of fines formation and its influence in SmW-EOR.

To calculate the brine speciation and the amount of precipitate formed at different pressure and temperature conditions, we use the Extended UNIQUAC model for 61 SmW-EOR experiments reported in literature. Both the amount of available soluble SO42- (aq) in the solution and the amount of CaSO4 precipitation has been calculated and correlated to the corresponding oil recovery.

Brine speciation after considering the substitution of Ca2+ by Mg2+ on chalk mineral surfaces showed possible precipitation of CaSO4 in most of the brine solutions. The amount of CaSO4(s) precipitate formed, increased with temperature and consequently the dissolved soluble SO42-(aq) decreased. Increased concentration of Ca2+,Mg2+ or SO42- ions compared to Sea Water-(SW) also enhanced the amount of precipitate formed. Increasing NaCl concentrations increased the solubility of SO42- and Ca2+ in SmW and decreased the amount of precipitate formed. The amount of precipitate formed in the pore space (after the substitution of Mg2+ on calcite surface) consistently correlated to the increased oil recovery observed in various experiments. While in several cases additional oil recovery did not correlate to the amount of soluble SO42- present in the SmW at equilibrium. These results together suggest that the substitution reaction on the mineral surface followed by solid fines formation is the fundamental reason behind the observed EOR. These results indicated that the observed wettability alteration in chalks may not be the primary cause but an additional effect of SmW-EOR.

This study shows how Extended UNIQUAC model can be used as a rigorous mathematical tool for understanding of the SmW-EOR in chalk. It also quantitatively explains a series of previous experiments reported in the literature and shows the importance of fine formation in SmW-EOR, both through correlation between modeling and experiments.
Experimental Study of Low Salinity and Optimal Salinity Surfactant Injection
Authors: Khanamiri Hamid Hosseinzade , Torsæter Ole , Stensen Jan Åge
Published: May 2015

Both experimental and field trials have shown that low salinity water (LS) injection produces incremental oil recovery. One of the major advantages of LS is that it lowers salinity, resulting in favorable conditions for the addition of chemicals such as surfactants to enhance oil recovery. Surfactant flooding can benefit from lower ionic strength as it becomes possible to use a large variety of surfactants which are not applicable at higher salinities. Lower surfactant adsorption at lower ionic strength reduces the need for using alkali. Surfactant injection can also be implemented at a lower concentration and probably without the need for a co-surfactant when used with LS water. These advantages may result in a cost-effective and more environmentally friendly chemical EOR.

In this investigation, laboratory surfactant flooding experiments were conducted with aged Berea sandstone cores. The samples were aged using a typical crude oil from the Norwegian Continental Shelf. In-situ brine contained both monovalent and divalent cations. The surfactant sodium dodecylbenzenesulfonate (SDBS) was used at concentrations of 0.05wt% and 0.2wt% to enhance oil recovery. In tertiary surfactant injection, low salinity surfactant (LSS) is injected after LS water and a high salinity water (HS) injected as the chase water after surfactant; however in after-tertiary surfactant injection the sequence was HS-LS-LSS. Combination of LS water with high salinity surfactant (HSS) was also investigated in two experiments with injection sequences of LS-HSS-HS and HS-HSS-LS. HS is waterflooding with the same salinity as in the HSS. HSS solution had ultralow interfacial tension with the crude oil.

LSS flooding with 0.2wt% SDBS concentration did not result in higher oil recovery than the flooding with 0.05wt% SDBS in tertiary LSS injection. Tertiary LSS injection had a better recovery than the after-tertiary LSS. Recovery by only surfactants in HS-HSS-LS was higher than that in LS-HSS-HS. However the whole injection in the latter had higher recovery than the former. All the results were reproduced through repeating experiments on a different type of Berea sandstone. Results were discussed in terms of ionic exchange between the rock and aqueous phase, surfactant retention and phase behavior. Interfacial tensions at different salinities were measured to find the optimal salinity before injection. Rock samples were characterized in micro scale using X-ray micro-CT, and the geometrical properties of pore and throat size distribution were extracted.

Maintaining optimal conditions of a multicomponent system during a dynamic flooding in alkaline-surfactant-polymer (ASP) is challenging. Produced oil and water by multiple chemicals is also expensive to treat. Improving performance of surfactant flooding by manipulating salinity and ionic composition of brine seems to be more convenient than designing and controlling a complex ASP injection.
The Effect of Mineral Deposition on CO2 Well Injectivity
Authors: Sokama-Neuyam Y. A. , Ursin J.
Published: May 2015

This paper presents results from laboratory investigations of CO2 injectivity losses in sandstone cores driven by minerals deposition. Parameters studied includes effect of brine salinity, gas injection rate and rock permeability. The results of the study indicates that mineral precipitation and CO2 injectivity is indeed dependent on brine salinity. We report that, injecting low salinity water into the core after mineral deposition could recover CO2 injectivity. Below certain salinity of brine, we observed significant injectivity is lost probably due to clay swelling effects. The results also indicates that mineral deposition depends on the brine displacement rate. We observed low injectivity losses at high gas injection rates. The investigation also revealed that mineral deposition effects depends on intial sandstone core permeability. Injectivity losses are significant in cores with lower initial permeability.
Wellbore Implosion: Case Study of Perforation Enhancement
Authors: Saadi Hassan Al , Mirza Muhammad , Jumaat Mohd Shafie
Published: May 2015

Good perforating practices are equally important for water injectors as for producers to achieve effective and efficient reservoir pressure support, which, in turn, results in better field productivity. An aspect of good perforating practice is to achieve clean perforations so that the injection skin is minimized. Dirty perforations, whether due to perforation debris or crushed zones around the perforation tunnel can affect a well's injectivity. This problem is further compounded when well injection starts as particles in injection water quickly accumulate at the perforations, causing rapid injectivity drop. Therefore, clean perforations are important to deliver good well injectivity.

This is a case study of a wellbore implosion technique on perforations of injector wells in a field in Oman. Compared to perforating in a high-pressure reservoir, achieving clean perforations in a low-pressure reservoir is more difficult as perforating has less potential to breakdown the crushed zone and to purge the crushed material together with the debris from the perforation tunnels. This problem may be overcome by the wellbore implosion technique, using a dynamic underbalance system.

Various perforating systems were tried for injector wells in this field. Reactive liner shaped charge, propellant system, and post-perforating dynamic underbalance techniques were used in the same well. A dynamic underbalance gun that creates wellbore implosion was designed, and recorded pressure gauge data were matched to the simulated data. Reservoir properties of each well from the logs and from the well injectivities after applying the above-mentioned perforating systems were compared. As the principle in this case study is perforation cleanup, it is also relevant to producers. It is also relevant to other wells whether on land or offshore, both producers and injectors of any pressure regime that could be suffering from poor cleanup of perforations.
Algorithmic randomness for Doob's martingale convergence theorem in continuous time
Authors: Kjos-Hanssen Bjørn , Nguyen Paul Kim Long V. , Rute Jason
Published: May 2015

We study Doob's martingale convergence theorem for computable continuous time
martingales on Brownian motion, in the context of algorithmic randomness. A
characterization of the class of sample points for which the theorem holds is
given. Such points are given the name of Doob random points. It is shown that a
point is Doob random if its tail is computably random in a certain sense.
Moreover, Doob randomness is strictly weaker than computable randomness and is
incomparable with Schnorr randomness.
Sub-computable Boundedness Randomness
Authors: Buss Sam , Cenzer Douglas , Remmel Jeffrey B.
Published: May 2015

This paper defines a new notion of bounded computable randomness for certain
classes of sub-computable functions which lack a universal machine. In
particular, we define such versions of randomness for primitive recursive
functions and for PSPACE functions. These new notions are robust in that there
are equivalent formulations in terms of (1) Martin-L\"of tests, (2) Kolmogorov
complexity, and (3) martingales. We show these notions can be equivalently
defined with prefix-free Kolmogorov complexity. We prove that one direction of
van Lambalgen's theorem holds for relative computability, but the other
direction fails. We discuss statistical properties of these notions of
randomness.
A Robust Class of Data Languages and an Application to Learning
Authors: Bollig Benedikt , Habermehl Peter , Leucker Martin , Monmege Benjamin
Published: May 2015

We introduce session automata, an automata model to process data words, i.e.,
words over an infinite alphabet. Session automata support the notion of fresh
data values, which are well suited for modeling protocols in which sessions
using fresh values are of major interest, like in security protocols or ad-hoc
networks. Session automata have an expressiveness partly extending, partly
reducing that of classical register automata. We show that, unlike register
automata and their various extensions, session automata are robust: They (i)
are closed under intersection, union, and (resource-sensitive) complementation,
(ii) admit a symbolic regular representation, (iii) have a decidable inclusion
problem (unlike register automata), and (iv) enjoy logical characterizations.
Using these results, we establish a learning algorithm to infer session
automata through membership and equivalence queries.
High-level Counterexamples for Probabilistic Automata
Authors: Wimmer Ralf , Jansen Nils , Ã?brahÃ?m Erika , Katoen Joost-Pieter
Published: May 2015

Providing compact and understandable counterexamples for violated system
properties is an essential task in model checking. Existing works on
counterexamples for probabilistic systems so far computed either a large set of
system runs or a subset of the system's states, both of which are of limited
use in manual debugging. Many probabilistic systems are described in a guarded
command language like the one used by the popular model checker PRISM. In this
paper we describe how a smallest possible subset of the commands can be
identified which together make the system erroneous. We additionally show how
the selected commands can be further simplified to obtain a well-understandable
counterexample.
Monads need not be endofunctors
Authors: Altenkirch Thosten , Chapman James , Uustalu Tarmo
Published: May 2015

We introduce a generalization of monads, called relative monads, allowing for
underlying functors between different categories. Examples include
finite-dimensional vector spaces, untyped and typed lambda-calculus syntax and
indexed containers. We show that the Kleisli and Eilenberg-Moore constructions
carry over to relative monads and are related to relative adjunctions. Under
reasonable assumptions, relative monads are monoids in the functor category
concerned and extend to monads, giving rise to a coreflection between relative
monads and monads. Arrows are also an instance of relative monads.
On the relative proof complexity of deep inference via atomic flows
Authors: Das Anupam
Published: May 2015

We consider the proof complexity of the minimal complete fragment, KS, of
standard deep inference systems for propositional logic. To examine the size of
proofs we employ atomic flows, diagrams that trace structural changes through a
proof but ignore logical information. As results we obtain a polynomial
simulation of versions of Resolution, along with some extensions. We also show
that these systems, as well as bounded-depth Frege systems, cannot polynomially
simulate KS, by giving polynomial-size proofs of certain variants of the
propositional pigeonhole principle in KS.
Program Logics for Homogeneous Generative Run-Time Meta-Programming
Authors: Berger Martin , Tratt Laurence
Published: May 2015

This paper provides the first program logic for homogeneous generative
run-time meta-programming---using a variant of MiniML by Davies and Pfenning as
its underlying meta-programming language. We show the applicability of our
approach by reasoning about example meta-programs from the literature. We also
demonstrate that our logics are relatively complete in the sense of Cook,
enable the inductive derivation of characteristic formulae, and exactly capture
the observational properties induced by the operational semantics.
Topologies on the set of Borel maps of class α
Authors: Georgiou D.N. , Megaritis A.C. , Petropoulos V.I.
Published: May 2015

Let ?1 be the first uncountable ordinal, ? < ?1 an ordinal, and Y, Z two
topological spaces. By B?(Y,Z) we denote the set of all Borel maps of class
? from Y into Z and by GZ?(Y) the set consisting of all subsets f -1(U),
where f ? B?(Y,Z) and U is an open subset of Z. In this paper we introduce
and investigate topologies on the sets B?(Y,Z) and GZ?(Y). More precisely,
we generalize the results presented by Arens, Dugundji, Aumann, and Rao (see
[1], [2], [3], and [10]) for Borel maps of class ?.
Completeness types for uniformity theory on textures
Authors: Yıldız Filiz
Published: May 2015

In this paper the author considers the various types of completeness for
di-uniform texture spaces and especially for complemented ones. Following
that, the relationships between completeness of uniform spaces and these
types of completeness for complemented di-uniform texture spaces are
investigated in a categorical setting, just as interrelations between
quasi-uniform spaces and di-uniform texture spaces are pointed out insofar as
completeness is concerned. Additionally, useful requirements among the
various types of completeness of a di-uniformity and real dicompactness of
the uniform ditopological space generated by that di-uniformity are presented
as a diagram.
Botrytis cinerea in raspberry in Serbia II: Growth rate and virulence of isolates
Authors: Tanovic Brankica , Hrustic Jovana , Mihajlovic Milica , Grahovac Mila , Delibasic Goran
Published: May 2015

Growth rate and virulence of 130 isolates of Botrytis cinerea, derived from
raspberry fruit originating from six commercial fields in a raspberry growing
region of Serbia and classified in two morphological and four genetic groups
were studied. The results showed significant differences in mycelial growth
rate among the isolates. The highest and lowest recorded growth rates were
24.5 mm/day and 8.4 mm/day, respectively, while the growth rate of most
isolates ranged from 15.8 to 21.8 mm/day. The growth rate of isolates that
belong to different morphological and genetic subgroups varied similarly.
Furthermore, growth rate intervals of all subgroups overlapped, suggesting
that the groups cannot be distinguished based on growth rates of the isolates
contained. The studied B. cinerea isolates exibited different levels of
virulence towards vine, sunflower and raspberry leaves, while an analysis of
variance revealed that both the isolates and the inoculated host species were
significant sources of variation (P<0.01). Sunflower and raspberry leaves
were significantly more sensitive than vine leaves. However, correlation
between isolate virulence and different hosts was not found.
Comparative characteristics of Lupinus albus L. and Lupinus luteus L. under allelopathic effect of Sorghum halepense L. (Pers.)
Authors: Georgieva Natalia , Nikolova Ivelina , Marinov-Serafimov Plamen
Published: May 2015

Allelopathic effects of aqueous extracts of Sorghum halepense L. (Pers.) on
seed germination and primary seedling growth and development of two lupine
species was studied. Lupinus albus and Lupinus luteus showed different levels
of susceptibility to the allelopathic effect of weed extracts. Increasing
concentrations (1.25, 2.50, 5.00 and 10.00%) of extracts from aboveground and
belowground biomass suppressed seed germination of L. luteus from 53.2 to
74.7%. The germination of L. albus seeds was unaffected, except by the
highest concentration of 10.00%. Fresh biomass accumulation in the initial
germ of L. luteus was inhibited by 3.8-40.3% under the effect of
concentrations of 2.50, 5.00 and 10.00%, which made the species susceptible
to S. halepense extracts. L. albus was tolerant as it was not found to
sustain a significant allelopathic effect of the extracts.
A model of the supplier involvement in the product innovation
Authors: Kumar Manoj , Raman Jyoti , Raman Priya
Published: May 2015

In this paper we examine the product innovation in a supply chain by a
supplier and derive a model for a supplier?s product innovation policy. The
product innovation of a supplier can contribute to the long-term
competitiveness for the supply chain, and as it is for many supply chains a
major factor, it should be considered in the development of strategies for a
supplier. Here, we evaluate the effectiveness of supplier product innovation
as a strategic tool to enhance the competitiveness and viability of supply
chain. This paper explores the dynamic research performance of a supplier
with endogenous time preference under a given arrangement of product
innovation. We find that the optimal effort level and the achieved product
innovation obey a saddle point path, or show tremendous fluctuations even
without introducing the stochastic nature of product innovative activity. We
also find that the fluctuation frequency is largely dependent both on the
supplier?s characteristics such as supplier?s product innovative ability and
on the nature of product innovation process per se. Short-run analyses are
also made on the effect of supply chain cooperation in the product innovation
process.
The Human Behavior Rating Scale–Brief: A Tool to Measure 21 Century Skills of K–12 Learners
Authors: Woods-Groves Suzanne
Published: May 2015

Currently there is a call for brief concise measurements to appraise relevant 21st century college readiness skills in K-12 learners. This study employed K-12 teachers' ratings for over 3,000 students for an existing 91-item rating scale, the Human Behavior Rating Scale, that measured the 21st century skills of persistence, curiosity, externalizing affect, internalizing affect, and cognition. Teachers' ratings for K-12 learners were used to develop a brief, concise, and manageable 30-item tool, the Human Behavior Rating Scale–Brief. Results yielded high internal consistency coefficients and inter-item correlations. The items were not biased with regard to student sex or race, and were supported through confirmatory factor analyses. In addition, when teachers' ratings were compared with students' academic and behavioral performance data, moderate to strong relationships were revealed. This study provided an essential first step in the development of a psychometrically sound, manageable, and brief tool to appraise 21st century skills in K-12 learners.
Corrigendum
Authors: Loveman Emma , Copley Vicky R , Colquitt Jill , Scott David A , Clegg Andy , Jones Jeremy , O’Reilly Katherine MA , Singh Sally , Bausewein Claudia , Wells Athol
Published: May 2015

Summary

A previous version of this report was published in July 2013. The report was corrected on page v in November 2013. For further information, or for copies of the original material, please contact Nihredit@soton.ac.uk.
Hepatoprotective effects of Sapium sebiferum in paracetamol-induced liver injury
Authors: Hussain Liaqat , Akash Muhammad Sajid Hamid , Tahir Madeha , Rehman Kanwal
Published: May 2015

Sapium sebiferum leaves were used to determine its hepatoprotective effects against paracetamol-induced hepatotoxicity in mice. A dose dependent study was conducted using two different doses (200 mg/kg and 400 mg/kg) of the extract of S. sebiferum against toxic effects of paracetamol (500 mg/kg) in experimental animal model. Silymarin (50 mg/kg) was used as standard drug to compare therapeutic effects of S. sebiferum with control and paracetamol-treated groups. Paracetamol significantly increased the serum levels of liver enzyme markers like alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, and direct bilirubin. The extract showed protective effects by normalizing the liver enzymes markers in a dose dependent manner. Histopathological results confirmed the hepatoprotective effects of leaves of S. sebiferum. We conclude that leaves of S. sebiferum have strong hepatoprotective effects against paracetamol-induced liver injury and can be used in liver injuries caused by drug-induced toxicity.
Symmetry-Related Electromagnetic Properties of Resonator-Loaded Transmission Lines and Applications
Authors: Naqui Jordi , Su Lijuan , Mata Javier , Martín Ferran
Published: May 2015

This paper reviews the recent progress in the analysis and applications of the symmetry-related electromagnetic properties of transmission lines loaded with symmetric configurations of resonant elements. It will be shown that the transmission characteristics of these reactively loaded lines can be controlled by the relative orientation between the line and the resonant elements. Two main types of loaded lines are considered: (i) resonance-based structures; and (ii) frequency-splitting structures. In resonance-based transmission lines, a line is loaded with a single resonant (and symmetric) element. For a perfectly symmetric structure, the line is transparent if the line and resonator exhibit symmetry planes of different electromagnetic nature (electric or magnetic wall), whereas the line exhibits a notch (resonance) in the transmission coefficient if the symmetry planes behave as either electric or magnetic walls (symmetric configuration), or if symmetry is broken. In frequency-splitting lines, paired resonators are typically loaded to the transmission line; the structure exhibits a single notch for the symmetric configuration, whereas generally two split notches appear when symmetry is disrupted. Applications of these structures include microwave sensors (e.g., contactless sensors of spatial variables), selective mode suppressors (of application in common-mode suppressed differential lines, for instance) and spectral signature barcodes, among others.
Roles of Prolyl Isomerases in RNA-Mediated Gene Expression
Authors: Thapar Roopa
Published: May 2015

The peptidyl-prolyl cis-trans isomerases (PPIases) that include immunophilins (cyclophilins and FKBPs) and parvulins (Pin1, Par14, Par17) participate in cell signaling, transcription, pre-mRNA processing and mRNA decay. The human genome encodes 19 cyclophilins, 18 FKBPs and three parvulins. Immunophilins are receptors for the immunosuppressive drugs cyclosporin A, FK506, and rapamycin that are used in organ transplantation. Pin1 has also been targeted in the treatment of Alzheimer’s disease, asthma, and a number of cancers. While these PPIases are characterized as molecular chaperones, they also act in a nonchaperone manner to promote protein-protein interactions using surfaces outside their active sites. The immunosuppressive drugs act by a gain-of-function mechanism by promoting protein-protein interactions in vivo. Several immunophilins have been identified as components of the spliceosome and are essential for alternative splicing. Pin1 plays roles in transcription and RNA processing by catalyzing conformational changes in the RNA Pol II C-terminal domain. Pin1 also binds several RNA binding proteins such as AUF1, KSRP, HuR, and SLBP that regulate mRNA decay by remodeling mRNP complexes. The functions of ribonucleoprotein associated PPIases are largely unknown. This review highlights PPIases that play roles in RNA-mediated gene expression, providing insight into their structures, functions and mechanisms of action in mRNP remodeling in vivo.
Entropy Approximation in Lossy Source Coding Problem
Authors: Śmieja Marek , Tabor Jacek
Published: May 2015

In this paper, we investigate a lossy source coding problem, where an upper limit on the permitted distortion is defined for every dataset element. It can be seen as an alternative approach to rate distortion theory where a bound on the allowed average error is specified. In order to find the entropy, which gives a statistical length of source code compatible with a fixed distortion bound, a corresponding optimization problem has to be solved. First, we show how to simplify this general optimization by reducing the number of coding partitions, which are irrelevant for the entropy calculation. In our main result, we present a fast and feasible for implementation greedy algorithm, which allows one to approximate the entropy within an additive error term of log2 e. The proof is based on the minimum entropy set cover problem, for which a similar bound was obtained.
Inhibitory Effect of Statins on Inflammation-Related Pathways in Human Abdominal Aortic Aneurysm Tissue
Authors: Yoshimura Koichi , Nagasawa Ayako , Kudo Junichi , Onoda Masahiko , Morikage Noriyasu , Furutani Akira , Aoki Hiroki , Hamano Kimikazu
Published: May 2015

HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitors (statins) have been suggested to attenuate abdominal aortic aneurysm (AAA) growth. However, the effects of statins in human AAA tissues are not fully elucidated. The aim of this study was to investigate the direct effects of statins on proinflammatory molecules in human AAA walls in ex vivo culture. Simvastatin strongly inhibited the activation of nuclear factor (NF)-κB induced by tumor necrosis factor (TNF)-α in human AAA walls, but showed little effect on c-jun N-terminal kinase (JNK) activation. Simvastatin, as well as pitavastatin significantly reduced the secretion of matrix metalloproteinase (MMP)-9, monocyte chemoattractant protein (MCP)-2 and epithelial neutrophil-activating peptide (CXCL5) under both basal and TNF-α-stimulated conditions. Similar to statins, the Rac1 inhibitor NSC23766 significantly inhibited the activation of NF-κB, accompanied by a decreased secretion of MMP-9, MCP-2 and CXCL5. Moreover, the effect of simvastatin and the JNK inhibitor SP600125 was additive in inhibiting the secretion of MMP-9, MCP-2 and CXCL5. These findings indicate that statins preferentially inhibit the Rac1/NF-κB pathway to suppress MMP-9 and chemokine secretion in human AAA, suggesting a mechanism for the potential effect of statins in attenuating AAA progression.
The Importance of Acidification in Atopic Eczema: An Underexplored Avenue for Treatment
Authors: Panther David , Jacob Sharon
Published: May 2015

Atopic dermatitis is a form of dermatitis commonly seen in children and adults. Its pathophysiology is complex and is centered on the barrier function of the epidermis. An important aspect of the skin’s barrier is pH, which in turn affects a number of parameters such as the skin flora, protease function, and mediators of inflammation and pruritus. Normal pH for non-neonatal skin is acidic and ranges from 4 to 6. Skin pH in atopic dermatitis patients is often increased into the neutral to basic range, and the resulting cascade of changes contributes to the phenotype of atopic dermatitis. Therefore, the maintenance of normal skin pH remains an important topic in understanding and treating atopic dermatitis. This article will review skin pH and its impact on normal barrier function, pathological pH changes in atopic dermatitis, and the therapeutic considerations related to restoring and maintaining pH balance.
Renal Biopsy in Type 2 Diabetic Patients
Authors: Espinel Eugenia , Agraz Irene , Ibernon Meritxell , Ramos Natalia , Fort Joan , Serón Daniel
Published: May 2015

The majority of diabetic patients with renal involvement are not biopsied. Studies evaluating histological findings in renal biopsies performed in diabetic patients have shown that approximately one third of the cases will show pure diabetic nephropathy, one third a non-diabetic condition and another third will show diabetic nephropathy with a superimposed disease. Early diagnosis of treatable non-diabetic diseases in diabetic patients is important to ameliorate renal prognosis. The publication of the International Consensus Document for the classification of type 1 and type 2 diabetes has provided common criteria for the classification of diabetic nephropathy and its utility to stratify risk for renal failure has already been demonstrated in different retrospective studies. The availability of new drugs with the potential to modify the natural history of diabetic nephropathy has raised the question whether renal biopsies may allow a better design of clinical trials aimed to delay the progression of chronic kidney disease in diabetic patients.
Multi-Threshold NULL Convention Logic (MTNCL): An Ultra-Low Power Asynchronous Circuit Design Methodology
Authors: Zhou Liang , Parameswaran Ravi , Parsan Farhad , Smith Scott , Di Jia
Published: May 2015

This paper develops an ultra-low power asynchronous circuit design methodology, called Multi-Threshold NULL Convention Logic (MTNCL), also known as Sleep Convention Logic (SCL), which combines Multi-Threshold CMOS (MTCMOS) with NULL Convention Logic (NCL), to yield significant power reduction without any of the drawbacks of applying MTCMOS to synchronous circuits. In contrast to other power reduction techniques that usually result in large area overhead, MTNCL circuits are actually smaller than their original NCL versions. MTNCL utilizes high-Vt transistors to gate power and ground of a low-Vt logic block to provide for both fast switching and very low leakage power when idle. To demonstrate the advantages of MTNCL, a number of 32-bit IEEE single-precision floating-point co-processors were designed for comparison using the 1.2 V IBM 8RF-LM 130 nm CMOS process: original NCL, MTNCL with just combinational logic (C/L) slept, Bit-Wise MTNCL (BWMTNCL), MTNCL with C/L and completion logic slept, MTNCL with C/L, completion logic, and registers slept, MTNCL with Safe Sleep architecture, and synchronous MTCMOS. These designs are compared in terms of throughput, area, dynamic energy, and idle power, showing the tradeoffs between the various MTNCL architectures, and that the best MTNCL design is much better than the original NCL design in all aspects, and much better than the synchronous MTCMOS design in terms of area, energy per operation, and idle power, although the synchronous design can operate faster.
Marine Polysaccharides from Algae with Potential Biomedical Applications
Authors: De Jesus Raposo Maria , De Morais Alcina , De Morais Rui
Published: May 2015

There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one type of these biochemical compounds that have already proved to have several important properties, such as anticoagulant and/or antithrombotic, immunomodulatory ability, antitumor and cancer preventive, antilipidaemic and hypoglycaemic, antibiotics and anti-inflammatory and antioxidant, making them promising bioactive products and biomaterials with a wide range of applications. Their properties are mainly due to their structure and physicochemical characteristics, which depend on the organism they are produced by. In the biomedical field, the polysaccharides from algae can be used in controlled drug delivery, wound management, and regenerative medicine. This review will focus on the biomedical applications of marine polysaccharides from algae.
Antitumor and Antimicrobial Activity of Some Cyclic Tetrapeptides and Tripeptides Derived from Marine Bacteria
Authors: Chakraborty Subrata , Tai Dar-Fu , Lin Yi-Chun , Chiou Tzyy-Wen
Published: May 2015

Marine derived cyclo(Gly-l-Ser-l-Pro-l-Glu) was selected as a lead to evaluate antitumor-antibiotic activity. Histidine was chosen to replace the serine residue to form cyclo(Gly-l-His-l-Pro-l-Glu). Cyclic tetrapeptides (CtetPs) were then synthesized using a solution phase method, and subjected to antitumor and antibiotic assays. The benzyl group protected CtetPs derivatives, showed better activity against antibiotic-resistant Staphylococcus aureus in the range of 60–120 μM. Benzyl group protected CtetPs 3 and 4, exhibited antitumor activity against several cell lines at a concentration of 80–108 μM. However, shortening the size of the ring to the cyclic tripeptide (CtriP) scaffold, cyclo(Gly-l-Ser-l-Pro), cyclo(Ser-l-Pro-l-Glu) and their analogues showed no antibiotic or antitumor activity. This phenomenon can be explained from their backbone structures.
SAR of Sponge-Inspired Hemibastadin Congeners Inhibiting Blue Mussel PhenolOxidase
Authors: Niemann Hendrik , Hagenow Jens , Chung Mi-Young , Hellio Claire , Weber Horst , Proksch Peter
Published: May 2015

Hemibastadin derivatives, including the synthetically-derived 5,5′-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation of the enzyme inhibitory activity of hemibastadin derivatives, we have synthesized nine new congeners, which feature structural variations of the DBHB core structure. These structural modifications include, e.g., different halogen substituents present at the aromatic rings, different amine moieties linked to the (E)-2-(hydroxyimino)-3-(4-hydroxyphenyl)propionic acid, the presence of free vs. substituted aromatic hydroxyl groups and a free vs. methylated oxime group. All compounds were tested for their inhibitory activity towards the target enzyme in vitro, and IC50 values were calculated. Derivatives, which structurally closely resemble sponge-derived hemibastadins, revealed superior enzyme inhibitory properties vs. congeners featuring structural moieties that are absent in the respective natural products. This study suggests that natural selection has yielded structurally-optimized antifouling compounds.
Current Understanding of Molecular Pathology and Treatment of Cardiomyopathy in Duchenne Muscular Dystrophy
Authors: Van Westering Tirsa , Betts Corinne , Wood Matthew
Published: May 2015

Duchenne muscular dystrophy (DMD) is a genetic muscle disorder caused by mutations in the Dmd gene resulting in the loss of the protein dystrophin. Patients do not only experience skeletal muscle degeneration, but also develop severe cardiomyopathy by their second decade, one of the main causes of death. The absence of dystrophin in the heart renders cardiomyocytes more sensitive to stretch-induced damage. Moreover, it pathologically alters intracellular calcium (Ca2+) concentration, neuronal nitric oxide synthase (nNOS) localization and mitochondrial function and leads to inflammation and necrosis, all contributing to the development of cardiomyopathy. Current therapies only treat symptoms and therefore the need for targeting the genetic defect is immense. Several preclinical therapies are undergoing development, including utrophin up-regulation, stop codon read-through therapy, viral gene therapy, cell-based therapy and exon skipping. Some of these therapies are undergoing clinical trials, but these have predominantly focused on skeletal muscle correction. However, improving skeletal muscle function without addressing cardiac aspects of the disease may aggravate cardiomyopathy and therefore it is essential that preclinical and clinical focus include improving heart function. This review consolidates what is known regarding molecular pathology of the DMD heart, specifically focusing on intracellular Ca2+, nNOS and mitochondrial dysregulation. It briefly discusses the current treatment options and then elaborates on the preclinical therapeutic approaches currently under development to restore dystrophin thereby improving pathology, with a focus on the heart.
Silver Nanoparticles as Potential Antibacterial Agents
Authors: Franci Gianluigi , Falanga Annarita , Galdiero Stefania , Palomba Luciana , Rai Mahendra , Morelli Giancarlo , Galdiero Massimiliano
Published: May 2015

Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.
Influence of Fruit Maturity at Harvest on the Intensity of Smoke Taint in Wine
Authors: Ristic Renata , Boss Paul , Wilkinson Kerry
Published: May 2015

Bushfire smoke can affect the composition and sensory properties of grapes and wines, in some cases leading to wines which exhibit undesirable “smoky”, “ashy” and “medicinal” characters. This study investigated the extent to which fruit maturity (i.e., ripeness) influences the perception of smoke taint in wine. Two white grape varieties (Chardonnay and Sauvignon Blanc) and two red grape varieties (Merlot and Shiraz) were exposed to smoke under experimental conditions, at approximately seven days post-veraison. Fruit was then harvested at two levels of maturity: Harvest A, when total soluble solids were 16–20 °Brix, i.e., the berry ripeness typically required for production of sparkling or light-bodied wines; and Harvest B, when total soluble solids were 22–25 °Brix, i.e., the berry ripeness typically required for production of full-bodied wines. The intensity of smoke taint in resulting wines was found to be influenced by fruit maturity, but differed between grape varieties. Smoke-related sensory attributes were apparent in Sauvignon Blanc wine made from early-harvested fruit and in Chardonnay wine made from late-harvested fruit, only; whereas Merlot and Shiraz wines exhibited smoke taint irrespective of fruit maturity. Smoke-derived volatile phenols, and various alcohols, esters and acids, were also quantified to determine the impact of smoke exposure and fruit maturity respectively, on wine composition.
Absorption and Metabolism Characteristics of Triptolide as Determined by a Sensitive and Reliable LC-MS/MS Method
Authors: Gong Xiaomei , Chen Yan , Wu Yi
Published: May 2015

In this research, a sensitive and reliable LC-MS/MS method was developed and applied to determine the concentration of triptolide in rat plasma, microsomes, and cell incubation media. The absolute oral bioavailability of triptolide is 63.9% at a dose of 1 mg·kg−1. In vitro, the bidirectional transport of triptolide across Caco-2 cells was studied. A markedly higher transport of triptolide across Caco-2 cells was observed in the basolateral-to-apical direction and was abrogated in the presence of the P-gp inhibitor, verapamil. The result indicated that P-gp might be involved in the absorption of triptolide in intestinal. The metabolic stability was also investigated using human liver microsome incubation systems in vitro. In HLMs, incubations with an initial triptolide concentration of 1 μM resulted in an 82.4% loss of substrate over 60 min, and the t1/2 was 38 min, which indicated that triptolide was easily metabolized in human liver microsomes. In conclusion, the absolute oral bioavailability of triptolide in plasma, transport across Caco-2 cell monolayers, and metabolic stability in human liver microsomes were systematically investigated by using a sensitive and reliable LC-MS/MS method.
Optical Scattering Cancellation through Arrays of Plasmonic Nanoparticles: A Review
Authors: Monti Alessio , Alù Andrea , Toscano Alessandro , Bilotti Filiberto
Published: May 2015

In this contribution, we review and discuss our recent results on the design of optical scattering cancellation devices based on an array of plasmonic nanoparticles. Starting from two different analytical models available to describe its electromagnetic behavior, we show that a properly designed array of plasmonic nanoparticles behaves both as an epsilon-near-zero metamaterial and as a reactive metasurface and, therefore, can be successfully used to reduce the optical scattering of a subwavelength object. Three different typologies of nanoparticle arrays are analyzed: spherical, core-shell, and ellipsoidal nanoparticles. We prove, both theoretically and through full-wave simulations, that such nanostructures can be successfully used as a cloaking device at ultraviolet and optical frequencies.
Ice Freeze-up and Break-up Detection of Shallow Lakes in Northern Alaska with Spaceborne SAR
Authors: Surdu Cristina , Duguay Claude , Pour Homa , Brown Laura
Published: May 2015

Shallow lakes, with depths less than ca. 3.5–4 m, are a ubiquitous feature of the Arctic Alaskan Coastal Plain, covering up to 40% of the land surface. With such an extended areal coverage, lakes and their ice regimes represent an important component of the cryosphere. The duration of the ice season has major implications for the regional and local climate, as well as for the physical and biogeochemical processes of the lakes. With day and night observations in all weather conditions, synthetic aperture radar (SAR) sensors provide year-round acquisitions. Monitoring the evolution of radar backscatter (σ°) is useful for detecting the timing of the beginning and end of the ice season. Analysis of the temporal evolution of C-band σ° from Advanced Synthetic Aperture Radar (ASAR) Wide Swath and RADARSAT-2 ScanSAR, with a combined frequency of acquisitions from two to five days, was employed to evaluate the potential of SAR to detect the timing of key lake-ice events. SAR observations from 2005 to 2011 were compared to outputs of the Canadian Lake Ice Model (CLIMo). Model simulations fall within similar ranges with those of the SAR observations, with a mean difference between SAR observations and model simulations of only one day for water-clear-of-ice (WCI) from 2006 to 2010. For freeze onset (FO), larger mean differences were observed. SAR analysis shows that the mean FO date for these shallow coastal lakes is 30 September and the mean WCI date is 5 July. Results reveal that greater variability existed in the mean FO date (up to 26 days) than in that of melt onset (MO) (up to 12 days) and in that of WCI (6 days). Additionally, this study also identifies limitations and provides recommendations for future work using C-band SAR for monitoring the lake- ice phenology of shallow Arctic lakes.
Fluorescence Characteristics and Lifetime Images of Photosensitizers of Talaporfin Sodium and Sodium Pheophorbide a in Normal and Cancer Cells
Authors: Awasthi Kamlesh , Yamamoto Kazuhito , Furuya Kazunari , Nakabayashi Takakazu , Li Liming , Ohta Nobuhiro
Published: May 2015

Fluorescence spectra and fluorescence lifetime images of talaporfin sodium and sodium-pheophorbide a, which can be regarded as photosensitizers for photodynamic therapy, were measured in normal and cancer cells. The reduction of the fluorescence intensity by photoirradiation was observed for both photosensitizers in both cells, but the quenching rate was much faster in cancer cells than in normal cells. These results are explained in terms of the excessive generation of reactive oxygen species via photoexcitation of these photosensitizers in cancer cells. The fluorescence lifetimes of both photosensitizers in cancer cells are different from those in normal cells, which originates from the different intracellular environments around the photosensitizers between normal and cancer cells.