bluuebunny/crossref_metadata_2025 huggingface dataset:
ELECTRONIC BAND STRUCTURE, OPTICAL, THERMAL AND BONDING PROPERTIES OF XMg2O4(X = Si, Ge) SPINEL COMPOUNDS
Authors: SEMARI F. , OUAHRANI T. , KHACHAI H. , KHENATA R. , RABAH M. , BOUHEMADOU A. , MURTAZA G. , AMIN B. , RACHED D.
Published: June 2013

Bonding nature as well as structural, optoelectronic and thermal properties of the cubic X Mg 2 O 4(X = Si , Ge ) spinel compounds have been calculated using a full-potential augmented plane-wave plus local orbitals (FP-APW+lo) method within the density functional theory. The exchange-correlation potential was treated with the PBE-GGA approximation to calculate the total energy. Moreover, the modified Becke–Johnson potential (TB-mBJ) was also applied to improve the electronic band structure calculations. The computed ground-state parameters (a, B, B′ and u) are in excellent agreements with the available theoretical data. Calculations of the electronic band structure and bonding properties show that these compounds have a direct energy band gap (Γ-Γ) with a dominated ionic character and the TB-mBJ approximation yields larger fundamental band gaps compared to those obtained using the PBE-GGA. Optical properties such as the complex dielectric function ε(ω), reflectivity R(ω) and energy loss function L(ω), for incident photon energy up to 40 eV, have been predicted. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the effects of pressure P and temperature T on the thermal expansion coefficient, Debye temperature and heat capacity for the considered compounds are investigated for the first time.
TRANSIENT TIME-FREQUENCY DISTRIBUTION BASED ON MONO-COMPONENT DECOMPOSITIONS
Authors: DANG PEI , QIAN TAO , GUO YUAN YUAN
Published: June 2013

In this paper we propose a new type of non-negative time-frequency distribution associated with mono-components in both the non-periodic and periodic cases, called transient time-frequency distribution (TTFD), and study its properties. The TTFD of a mono-component signal can be obtained directly through its analytic instantaneous frequency. The characteristic property of TTFD is its complete concentration along the analytic instantaneous frequency graph. For multi-components there are induced time-frequency distributions called composing transient time-frequency distribution (CTTFD). Each CTTFD is defined as the superposition of the TTFDs of the composing intrinsic mono-components in a suitable mono-components decomposition of the targeted multi-component. In studying the properties of TTFD and CTTFD the relations between the Fourier frequency and analytic instantaneous frequency are examined.
HYPER-PARAMETER SELECTION FOR SPARSE LS-SVM VIA MINIMIZATION OF ITS LOCALIZED GENERALIZATION ERROR
Authors: SUN BINBIN , NG WING W. Y. , YEUNG DANIEL S. , CHAN PATRICK P. K.
Published: June 2013

Sparse LS-SVM yields better generalization capability and reduces prediction time in comparison to full dense LS-SVM. However, both methods require careful selection of hyper-parameters (HPS) to achieve high generalization capability. Leave-One-Out Cross Validation (LOO-CV) and k-fold Cross Validation (k-CV) are the two most widely used hyper-parameter selection methods for LS-SVMs. However, both fail to select good hyper-parameters for sparse LS-SVM. In this paper we propose a new hyper-parameter selection method, LGEM-HPS, for LS-SVM via minimization of the Localized Generalization Error (L-GEM). The L-GEM consists of two major components: empirical mean square error and sensitivity measure. A new sensitivity measure is derived for LS-SVM to enable the LGEM-HPS select hyper-parameters yielding LS-SVM with smaller training error and minimum sensitivity to minor changes in inputs. Experiments on eleven UCI data sets show the effectiveness of the proposed method for selecting hyper-parameters for sparse LS-SVM.
A NEW SUPERCLASS OF BLOCK BACKWARD DIFFERENTIATION FORMULA FOR STIFF ORDINARY DIFFERENTIAL EQUATIONS
Authors: Suleiman M. B. , Musa H. , Ismail F. , Senu N. , Ibrahim Z. B.
Published: June 2013

A superclass of block backward differentiation formula (BBDF) suitable for solving stiff ordinary differential equations is developed. The method is of order 3, with smaller error constant than the conventional BBDF. It is A-stable and generates two points at each step of the integration. A comparison is made between the new method, the 2-point block backward differentiation formula (2BBDF) and 1-point backward differentiation formula (1BDF). The numerical results show that the method developed outperformed the 2BBDF and 1BDF methods in terms of accuracy. It also reduces the integration steps when compared with the 1BDF method.
A test-based security certification scheme for web services
Authors: Anisetti Marco , Ardagna Claudio A. , Damiani Ernesto , Saonara Francesco
Published: June 2013

The Service-Oriented Architecture (SOA) paradigm is giving rise to a new generation of applications built by dynamically composing loosely coupled autonomous services. Clients (i.e., software agents acting on behalf of human users or service providers) implementing such complex applications typically search and integrate services on the basis of their functional requirements and of their trust in the service suppliers. A major issue in this scenario relates to the definition of an assurance technique allowing clients to select services on the basis of their nonfunctional requirements and increasing their confidence that the selected services will satisfy such requirements. In this article, we first present an assurance solution that focuses on security and supports a test-based security certification scheme for Web services. The certification scheme is driven by the security properties to be certified and relies upon a formal definition of the service model. The evidence supporting a certified property is computed using a model-based testing approach that, starting from the service model, automatically generates the test cases to be used in the service certification. We also define a set of indexes and metrics that evaluate the assurance level and the quality of the certification process. Finally, we present our evaluation toolkit and experimental results obtained applying our certification solution to a financial service implementing the Interactive Financial eXchange (IFX) standard.
Understanding query interfaces by statistical parsing
Authors: Su Weifeng , Wu Hejun , Li Yafei , Zhao Jing , Lochovsky Frederick H. , Cai Hongmin , Huang Tianqiang
Published: June 2013

Users submit queries to an online database via its query interface. Query interface parsing, which is important for many applications, understands the query capabilities of a query interface. Since most query interfaces are organized hierarchically, we present a novel query interface parsing method, StatParser (Statistical Parser), to automatically extract the hierarchical query capabilities of query interfaces. StatParser automatically learns from a set of parsed query interfaces and parses new query interfaces. StatParser starts from a small grammar and enhances the grammar with a set of probabilities learned from parsed query interfaces under the maximum-entropy principle. Given a new query interface, the probability-enhanced grammar identifies the parse tree with the largest global probability to be the query capabilities of the query interface. Experimental results show that StatParser very accurately extracts the query capabilities and can effectively overcome the problems of existing query interface parsers.
A language for end-user web augmentation
Authors: Díaz Oscar , Arellano Cristóbal , Azanza Maider
Published: June 2013

Web augmentation is to the Web what augmented reality is to the physical world: layering relevant content/layout/navigation over the existing Web to customize the user experience. This is achieved through JavaScript (JS) using browser weavers (e.g., Greasemonkey). To date, over 43 million of downloads of Greasemonkey scripts ground the vitality of this movement. However, Web augmentation is hindered by being programming intensive and prone to malware. This prevents end-users from participating as both producers and consumers of scripts: producers need to know JS, consumers need to trust JS. This article aims at promoting end-user participation in both roles. The vision is for end-users to prosume (the act of simultaneously caring for producing and consuming) scripts as easily as they currently prosume their pictures or videos. Encouraging production requires more “natural” and abstract constructs. Promoting consumption calls for augmentation scripts to be easier to understand, share, and trust upon. To this end, we explore the use of
Domain-Specific Languages
(DSLs) by introducing
Sticklet
. Sticklet is an internal DSL on JS, where JS generality is reduced for the sake of learnability and reliability. Specifically, Web augmentation is conceived as fixing in existing web sites (i.e.,
the wall
) HTML fragments extracted from either other sites or Web services (i.e.,
the stickers
). Sticklet targets hobby programmers as producers, and computer literates as consumers. From a producer perspective, benefits are threefold. As a restricted grammar on top of JS, Sticklet expressions are domain oriented and more declarative than their JS counterparts, hence speeding up development. As syntactically correct JS expressions, Sticklet scripts can be installed as traditional scripts and hence, programmers can continue using existing JS tools. As declarative expressions, they are easier to maintain, and amenable for optimization. From a consumer perspective, domain specificity brings understandability (due to declarativeness), reliability (due to built-in security), and “consumability” (i.e., installation/enactment/sharing of Sticklet expressions are tuned to the shortage of time and skills of the target audience). Preliminary evaluations indicate that 77% of the subjects were able to develop new Sticklet scripts in less than thirty minutes while 84% were able to consume these scripts in less than ten minutes. Sticklet is available to download as a Mozilla add-on.
Coordinating the web of services for a smart home
Authors: Kaldeli Eirini , Warriach Ehsan Ullah , Lazovik Alexander , Aiello Marco
Published: June 2013

Domotics, concerned with the realization of intelligent home environments, is a novel field which can highly benefit from solutions inspired by service-oriented principles to enhance the convenience and security of modern home residents. In this work, we present an architecture for a smart home, starting from the lower device interconnectivity level up to the higher application layers that undertake the load of complex functionalities and provide a number of services to end-users. We claim that in order for smart homes to exhibit a genuinely intelligent behavior, the ability to compute compositions of individual devices automatically and dynamically is paramount. To this end, we incorporate into the architecture a composition component that employs artificial intelligence domain-independent planning to generate compositions at runtime, in a constantly evolving environment. We have implemented a fully working prototype that realizes such an architecture, and have evaluated it both in terms of performance as well as from the end-user point of view. The results of the evaluation show that the service-oriented architectural design and the support for dynamic compositions is quite efficient from the technical point of view, and that the system succeeds in satisfying the expectations and objectives of the users.
Design and Evaluation of Soft Keyboards for Brahmic Scripts
Authors: Hinkle Lauren , Brouillette Albert , Jayakar Sujay , Gathings Leigh , Lezcano Miguel , Kalita Jugal
Published: June 2013

Despite being spoken by a large percentage of the world, Indic languages in general lack user-friendly and efficient methods for text input. These languages have poor or no support for typing. Soft keyboards, because of their ease of installation and lack of reliance on specific hardware, are a promising solution as an input device for many languages. Developing an acceptable soft keyboard requires the frequency analysis of characters in order to design a layout that minimizes text-input time. This article proposes the use of various development techniques, layout variations, and evaluation methods for the creation of soft keyboards for Brahmic scripts. We propose that using optimization techniques such as genetic algorithms and multi-objective Pareto optimization to develop multi-layer keyboards will increase the speed at which text can be entered.
Spin-transfer torque magnetic random access memory (STT-MRAM)
Authors: Apalkov Dmytro , Khvalkovskiy Alexey , Watts Steven , Nikitin Vladimir , Tang Xueti , Lottis Daniel , Moon Kiseok , Luo Xiao , Chen Eugene , Ong Adrian , Driskill-Smith Alexander , Krounbi Mohamad
Published: June 2013

Spin-transfer torque magnetic random access memory (STT-MRAM) is a novel, magnetic memory technology that leverages the base platform established by an existing 100+nm node memory product called MRAM to enable a scalable nonvolatile memory solution for advanced process nodes. STT-MRAM features fast read and write times, small cell sizes of 6F
2
and potentially even smaller, and compatibility with existing DRAM and SRAM architecture with relatively small associated cost added. STT-MRAM is essentially a magnetic multilayer resistive element cell that is fabricated as an additional metal layer on top of conventional CMOS access transistors. In this review we give an overview of the existing STT-MRAM technologies currently in research and development across the world, as well as some specific discussion of results obtained at Grandis and with our foundry partners. We will show that in-plane STT-MRAM technology, particularly the DMTJ design, is a mature technology that meets all conventional requirements for an STT-MRAM cell to be a nonvolatile solution matching DRAM and/or SRAM drive circuitry. Exciting recent developments in perpendicular STT-MRAM also indicate that this type of STT-MRAM technology may reach maturity faster than expected, allowing even smaller cell size and product introduction at smaller nodes.
Parametric Content-Based Publish/Subscribe
Authors: Jayaram K. R. , Eugster Patrick , Jayalath Chamikara
Published: June 2013

Content-based publish/subscribe (CPS) is an appealing abstraction for building scalable distributed systems, e.g., message boards, intrusion detectors, or algorithmic stock trading platforms. Recently, CPS extensions have been proposed for location-based services like vehicular networks, mobile social networking, and so on.

Although current CPS middleware systems are dynamic in the way they support the joining and leaving of publishers and subscribers, they fall short in supporting subscription adaptations. These are becoming increasingly important across many CPS applications. In algorithmic high frequency trading, for instance, stock price thresholds that are of interest to a trader change rapidly, and gains directly hinge on the reaction time to relevant fluctuations rather than fixed values. In location-aware applications, a subscription is a function of the subscriber location (e.g. GPS coordinates), which inherently changes during motion.

The common solution for adapting a subscription consists of a resubscription, where a new subscription is issued and the superseded one canceled. This incurs substantial overhead in CPS middleware systems, and leads to missed or duplicated events during the transition. In this article, we explore the concept of parametric subscriptions for capturing subscription adaptations. We discuss desirable and feasible guarantees for corresponding support, and propose novel algorithms for updating routing mechanisms effectively and efficiently in classic decentralized CPS broker overlay networks. Compared to resubscriptions, our algorithms significantly improve the reaction time to subscription updates without hampering throughput or latency under high update rates. We also propose and evaluate approximation techniques to detect and mitigate pathological cases of high frequency subscription oscillations, which could significantly decrease the throughput of CPS systems thereby affecting other subscribers.

We analyze the benefits of our support through implementations of our algorithms in two CPS systems, and by evaluating our algorithms on two different application scenarios.
Mechanism Design via Consensus Estimates, Cross Checking, and Profit Extraction
Authors: Ha Bach Q. , Hartline Jason D.
Published: June 2013

There is only one technique for
prior-free optimal mechanism design
that generalizes beyond the structurally benevolent setting of digital goods. This technique uses random sampling to estimate the distribution of agent values and then employs the
Bayesian optimal mechanism
for this estimated distribution on the remaining players. Though quite general, even for digital goods, this random sampling auction has a complicated analysis and is known to be suboptimal. To overcome these issues we generalize the consensus and profit extraction techniques from Goldberg and Hartline [2003] to structurally rich environments that include, for example, single-minded combinatorial auctions.
On the Competitive Ratio of Online Sampling Auctions
Authors: Koutsoupias Elias , Pierrakos George
Published: June 2013

We study online profit-maximizing auctions for digital goods with adversarial bid selection and uniformly random arrivals; in this sense, our model lies at the intersection of prior-free mechanism design and secretary problems. Our goal is to design auctions that are constant competitive with
F
(2)
. We give a generic reduction that transforms any offline auction to an online one with only a loss of a factor of 2 in the competitive ratio. We also present some natural auctions, both randomized and deterministic, and study their competitive ratio. Our analysis reveals some interesting connections of one of these auctions with RSOP.
Efficient Market Making via Convex Optimization, and a Connection to Online Learning
Authors: Abernethy Jacob , Chen Yiling , Vaughan Jennifer Wortman
Published: June 2013

We propose a general framework for the design of securities markets over combinatorial or infinite state or outcome spaces. The framework enables the design of computationally efficient markets tailored to an arbitrary, yet relatively small, space of securities with bounded payoff. We prove that any market satisfying a set of intuitive conditions must price securities via a convex cost function, which is constructed via conjugate duality. Rather than deal with an exponentially large or infinite outcome space directly, our framework only requires optimization over a convex hull. By reducing the problem of automated market making to convex optimization, where many efficient algorithms exist, we arrive at a range of new polynomial-time pricing mechanisms for various problems. We demonstrate the advantages of this framework with the design of some particular markets. We also show that by relaxing the convex hull we can gain computational tractability without compromising the market institution’s bounded budget. Although our framework was designed with the goal of deriving efficient automated market makers for markets with very large outcome spaces, this framework also provides new insights into the relationship between market design and machine learning, and into the complete market setting. Using our framework, we illustrate the mathematical parallels between cost-function-based markets and online learning and establish a correspondence between cost-function-based markets and market scoring rules for complete markets.
Cueing multimedia search with audiovisual blur
Authors: Bouchara Tifanie , Jacquemin Christian , Katz Brian F. G.
Published: June 2013

Situated in the context of multimedia browsing, this study concerns perceptual processes involved in searching for an audiovisual object displayed among several distractors. The aim of the study is to increase the perceptual saliency of the target in order to enhance the search process. As blurring distractors and maintaining the target sharp has proved to be a great facilitator of visual search, we propose combining visual blur with an audio blur analogue to improve multimodal search. Three perceptual experiments were performed in which participants had to retrieve an audiovisual object from a set of six competing stimuli. The first two experiments explored the effect of blur level on unimodal search tasks. A third experiment investigated the influence of an audio and visual modality combination with both modalities cued on an audiovisual search task. Results showed that both visual and audio blurs render stimuli distractors less prominent and thus helped users focus on a sharp target more easily. Performances were also faster and more accurate in the bimodal condition than in either unimodal search task, auditory or visual. Our work suggests that audio and audiovisual interfaces dedicated to multimedia search could benefit from different uses of blur on presentation strategies.
Graph-based joint clustering of fixations and visual entities
Authors: Sugano Yusuke , Matsushita Yasuyuki , Sato Yoichi
Published: June 2013

We present a method that extracts groups of fixations and image regions for the purpose of gaze analysis and image understanding. Since the attentional relationship between visual entities conveys rich information, automatically determining the relationship provides us a semantic representation of images. We show that, by jointly clustering human gaze and visual entities, it is possible to build meaningful and comprehensive metadata that offer an interpretation about how people see images. To achieve this, we developed a clustering method that uses a joint graph structure between fixation points and over-segmented image regions to ensure a cross-domain smoothness constraint. We show that the proposed clustering method achieves better performance in relating attention to visual entities in comparison with standard clustering techniques.
Parallelizing Sequential Programs with Statistical Accuracy Tests
Authors: Misailovic Sasa , Kim Deokhwan , Rinard Martin
Published: June 2013

We present QuickStep, a novel system for parallelizing sequential programs. Unlike standard parallelizing compilers (which are designed to preserve the semantics of the original sequential computation), QuickStep is instead designed to generate (potentially nondeterministic) parallel programs that produce acceptably accurate results acceptably often. The freedom to generate parallel programs whose output may differ (within statistical accuracy bounds) from the output of the sequential program enables a dramatic simplification of the compiler, a dramatic increase in the range of applications that it can parallelize, and a significant expansion in the range of parallel programs that it can legally generate.

Results from our benchmark set of applications show that QuickStep can automatically generate acceptably accurate and efficient parallel programs---the automatically generated parallel versions of five of our six benchmark applications run between 5.0 and 7.8 times faster on eight cores than the original sequential versions. These applications and parallelizations contain features (such as the use of modern object-oriented programming constructs or desirable parallelizations with infrequent but acceptable data races) that place them inherently beyond the reach of standard approaches.
Hardware-Based Load Value Trace Filtering for On-the-Fly Debugging
Authors: Uzelac Vladimir , Milenković Aleksandar
Published: June 2013

Capturing program and data traces during program execution unobtrusively on-the-fly is crucial in debugging and testing of cyber-physical systems. However, tracing a complete program unobtrusively is often cost-prohibitive, requiring large on-chip trace buffers and wide trace ports. This article describes a new hardware-based load data value filtering technique called Cache First-access Tracking. Coupled with an effective variable encoding scheme, this technique achieves a significant reduction of load data value traces, from 5.86 to 56.39 times depending on the data cache size, thus enabling cost-effective, unobtrusive on-the-fly tracing and debugging.
Enhancing RSSI-based tracking accuracy in wireless sensor networks
Authors: Blumrosen Gaddi , Hod Bracha , Anker Tal , Dolev Danny , Rubinsky Boris
Published: June 2013

In recent years, the demand for high-precision tracking systems has significantly increased in the field of Wireless Sensor Network (WSN). A new tracking system based on exploitation of Received Signal Strength Indicator (RSSI) measurements in WSN is proposed. The proposed system is designed in particular for WSNs that are deployed in close proximity and can transmit data at a high transmission rate. The close proximity and an optimized transmit power level enable accurate conversion of RSSI measurements to range estimates. Having an adequate transmission rate enables spatial-temporal correlation between consecutive RSSI measurements. In addition, advanced statistical and signal processing methods are used to mitigate channel distortion and to compensate for packet loss. The system is evaluated in indoor conditions and achieves tracking resolution of a few centimeters which is compatible with theoretical bounds.
Real-time routing in wireless sensor networks
Authors: Xu Yinsheng , Ren Fengyuan , He Tao , Lin Chuang , Chen Canfeng , Das Sajal K.
Published: June 2013

Wireless Sensor Networks (WSNs) are embracing an increasing number of real-time applications subject to strict delay constraints. Utilizing the methodology of potential field in physics, in this article we effectively address the challenges of real-time routing in WSNs. In particular, based on a virtual composite potential field, we propose the Potential-based Real-Time Routing (PRTR) protocol that supports real-time routing using multipath transmission. PRTR minimizes delay for real-time traffic and alleviates possible congestions simultaneously. Since the delay bounds of real-time flows are extremely important, the end-to-end delay bound for a single flow is derived based on the
Network Calculus
theory. The simulation results show that PRTR minimizes the end-to-end delay for real-time routing, and also guarantees a tight bound on the delay.
A novel reconfigurable architecture of a DSP processor for efficient mapping of DSP functions using field programmable DSP arrays
Authors: Sinha Amitabha , Sarkar Mitrava , Acharyya Soumojit , Chakraborty Suranjan
Published: June 2013

Development of modern integrated circuit technologies makes it feasible to develop cheaper, faster and smaller special purpose signal processing function circuits. Digital Signal processing functions are generally implemented either on ASICs with inflexibility, or on FPGAs with bottlenecks of relatively smaller utilization factor or lower speed compared to ASIC. Field Programmable DSP Array (FPDA) is the proposed DSP dedicated device, redolent to FPGA, but with basic fixed common modules (CMs) (like adders, subtractors, multipliers, scaling units, shifters) instead of CLBs. This paper introduces the development of reconfigurable system architecture with a focus on FPDA that integrates different DSP functions like DFT, FFT, DCT, FIR, IIR, and DWT etc. The switching between DSP functions is occurred by reconfiguring the interconnection between CMs. Validation of the proposed architecture has been achieved on Virtex5 FPGA. The architecture provides sufficient amount of flexibility, parallelism and scalability.
Distributing trusted third parties
Authors: Küpçü Alptekin
Published: June 2013

Trusted Third Parties (TTPs) are widely employed in various scenarios for providing fairness guarantees (e.g., in fair exchange or e-commerce protocols, including secure two-party computation), for distributing secrets (e.g., in authentication or secret-sharing protocols, as well as group signatures), and for creating trust (e.g., as certificate authorities). Such wide use of TTPs, as well as the trust requirement that is put on them make them a prime target for distributed systems and cryptography research.

There are some well-known and proven solutions to the problem of distributing the trust put on TTPs: byzantine agreement or secure multi-party computation techniques can be employed to distribute the job of any TTP to multiple parties, tolerating up to half or one-third of those parties being malicious. Such techniques are not widely-employed in practice possibly due to their quadratic complexity or inter-operation requirements. This brings up the question of distributing TTPs in a much more efficient way, possibly via using autonomous agents, who do not directly communicate with each other.

In this paper, we present various known techniques for distributing the trust put on TTPs. Then, we concentrate on using multiple autonomous parties, who do not communicate with each other at all, to realize a single TTP. We discuss the role of synchrony in such attempts, and conclude with some open questions.
Recent advances on the matroid secretary problem
Authors: Dinitz Michael
Published: June 2013

The matroid secretary problem was introduced by Babaioff, Immorlica, and Kleinberg in SODA 2007 as an online problem that was both mathematically interesting and had applications to online auctions. In this column I will introduce and motivate this problem, and give a survey of some of the exciting work that has been done on it over the past 6 years. While we have a much better understanding of matroid secretary now than we did in 2007, the main conjecture is still open: does there exist an O(1)-competitive algorithm.
One year of sitagliptin treatment protects against islet amyloid-associated β-cell loss and does not induce pancreatitis or pancreatic neoplasia in mice
Authors: Aston-Mourney Kathryn , Subramanian Shoba L. , Zraika Sakeneh , Samarasekera Thanya , Meier Daniel T. , Goldstein Lynn C. , Hull Rebecca L.
Published: June 2013

The dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin is an attractive therapy for diabetes, as it increases insulin release and may preserve β-cell mass. However, sitagliptin also increases β-cell release of human islet amyloid polypeptide (hIAPP), the peptide component of islet amyloid, which is cosecreted with insulin. Thus, sitagliptin treatment may promote islet amyloid formation and its associated β-cell toxicity. Conversely, metformin treatment decreases islet amyloid formation by decreasing β-cell secretory demand and could therefore offset sitagliptin's potential proamyloidogenic effects. Sitagliptin treatment has also been reported to be detrimental to the exocrine pancreas. We investigated whether long-term sitagliptin treatment, alone or with metformin, increased islet amyloid deposition and β-cell toxicity and induced pancreatic ductal proliferation, pancreatitis, and/or pancreatic metaplasia/neoplasia. hIAPP transgenic and nontransgenic littermates were followed for 1 yr on no treatment, sitagliptin, metformin, or the combination. Islet amyloid deposition, β-cell mass, insulin release, and measures of exocrine pancreas pathology were determined. Relative to untreated mice, sitagliptin treatment did not increase amyloid deposition, despite increasing hIAPP release, and prevented amyloid-induced β-cell loss. Metformin treatment alone or with sitagliptin decreased islet amyloid deposition to a similar extent vs untreated mice. Ductal proliferation was not altered among treatment groups, and no evidence of pancreatitis, ductal metaplasia, or neoplasia were observed. Therefore, long-term sitagliptin treatment stimulates β-cell secretion without increasing amyloid formation and protects against amyloid-induced β-cell loss. This suggests a novel effect of sitagliptin to protect the β-cell in type 2 diabetes that appears to occur without adverse effects on the exocrine pancreas.
Silencing of ghrelin receptor expression inhibits endometrial cancer cell growth in vitro and in vivo
Authors: Fung Jenny N. T. , Jeffery Penny L. , Lee John D. , Seim Inge , Roche Deborah , Obermair Andreas , Chopin Lisa K. , Chen Chen
Published: June 2013

Ghrelin is a 28-amino acid peptide hormone produced predominantly in the stomach but also in a range of normal cell types and tumors, where it has endocrine, paracrine, and autocrine roles. Previously, we have demonstrated that ghrelin has proliferative and antiapoptotic effects in endometrial cancer cell lines, suggesting a potential role in promoting tumor growth. In the present study, we investigated the effect of ghrelin receptor, GHSR, and gene silencing in vitro and in vivo and characterized ghrelin and GHSR1a protein expression in human endometrial tumors. GHSR gene silencing was achieved in the Ishikawa and KLE endometrial cancer cell lines, using a lentiviral short-hairpin RNA targeting GHSR. The effects of GHSR1a knockdown were further analyzed in vivo using the Ishikawa cell line in a NOD/SCID xenograft model. Cell proliferation was reduced in cultured GHSR1a knockdown Ishikawa and KLE cells compared with scrambled controls in the absence of exogenously applied ghrelin and in response to exogenous ghrelin (1,000 nM). The tumor volumes were reduced significantly in GHSR1a knockdown Ishikawa mouse xenograft tumors compared with scrambled control tumours. Using immunohistochemistry, we demonstrated that ghrelin and GHSR1a are expressed in benign and cancerous glands in human endometrial tissue specimens, although there was no correlation between the intensity of staining and cancer grade. These data indicate that downregulation of GHSR expression significantly inhibits endometrial cancer cell line and mouse xenograft tumour growth. This is the first preclinical evidence that downregulation of GHSR may be therapeutic in endometrial cancer.
Effects of transaldolase exchange on estimates of gluconeogenesis in type 2 diabetes
Authors: Rajpal Aman , Dube Simmi , Carvalho Filipa , Simoes Ana Rita , Figueiredo Angelo , Basu Ananda , Jones John , Basu Rita
Published: June 2013

Transaldolase (TA) exchange overestimates gluconeogenesis measured with deuterated water (2H2O). However, it is unknown whether TA differs in people with type 2 diabetes (T2DM).2H2O was ingested, and [1-13C]acetate and [3-3H]glucose were infused in T2DM ( n = 10) and healthy nondiabetic (ND; n = 8) subjects. TA was assessed from the ratio of13C3 to13C4 glucose enrichment (13C3/13C4) measured by13C NMR. Glucose turnover was measured before (∼16-h fast) and during hyperglycemic (∼10 mM) moderate-dose insulin (∼0.35 mU·kg−1·min−1) clamp.13C3/13C4 in T2DM vs. ND was <1.0 and not different at baseline and clamp, indicating equivalent TA. To determine whether incomplete triose phosphate isomerase (TPI) exchange contributed to asymmetric13C3/13C4, [U-13C]glycerol was infused in lieu of [1-13C]acetate during a separate visit in a subset of ND ( n = 7) subjects. Ratio of13C3/13C4 obtained following either tracer was <1.0 at baseline and during clamp, indicating that TPI exchange was essentially complete and did not contribute to asymmetric glucose enrichment. Uncorrected and corrected rates of gluconeogenesis were no different ( P = not significant) in T2DM vs. ND both at baseline and during clamp. TA correction resulted in equivalent estimates of corrected gluconeogenesis in T2DM and ND that were ∼25–35% lower than uncorrected gluconeogenesis both at baseline and during the clamp. The asymmetric enrichment of glucose from13C-gluconeogenic tracers is attributable to TA exchange and can be utilized to correct for TA exchange. In conclusion, TA exchange does not differ between T2DM and ND under fasting or hyperglycemic clamp conditions, and the2H2O method continues to provide an accurate estimation of gluconeogenesis.
Interactions between p-Akt and Smad3 in injured muscles initiate myogenesis or fibrogenesis
Authors: Dong Yanjun , Lakhia Ronak , Thomas Sandhya S. , Dong Yanlan , Wang Xiaonan H. , Silva Kleiton Augusto Santos , Zhang Liping
Published: June 2013

In catabolic conditions such as aging and diabetes, IGF signaling is impaired and fibrosis develops in skeletal muscles. To examine whether impaired IGF signaling initiates muscle fibrosis, we generated IGF-IR+/− heterozygous mice by crossing loxP-floxed IGF-IR (exon 3) mice with MyoD-cre mice. IGF-IR+/− mice were studied because we were unable to obtain homozygous IGF-IR-KO mice. In IGF-IR+/− mice, both growth and expression of myogenic genes (MyoD and myogenin; markers of satellite cell proliferation and differentiation, respectively) were depressed. Likewise, in injured muscles of IGF-IR+/− mice, there was impaired regeneration, depressed expression of MyoD and myogenin, and increased expression of TGF-β1, α-SMA, collagen I, and fibrosis. To uncover mechanisms stimulating fibrosis, we isolated satellite cells from muscles of IGF-IR+/− mice and found reduced proliferation and differentiation plus increased TGF-β1 production. In C2C12 myoblasts (a model of satellite cells), IGF-I treatment inhibited TGF-β1-stimulated Smad3 phosphorylation, its nuclear translocation, and expression of fibronectin. Using immunoprecipitation assay, we found an interaction between p-Akt or Akt with Smad3 in wild-type mouse muscles and in C2C12 myoblasts; importantly, IGF-I increased p-Akt and Smad3 interaction, whereas TGF-β1 decreased it. Therefore, in muscles of IGF-IR+/− mice, the reduction in IGF-IR reduces p-Akt, allowing for dissociation and nuclear translocation of Smad3 to enhance the TGF-β1 signaling pathway, leading to fibrosis. Thus, strategies to improve IGF signaling could prevent fibrosis in catabolic conditions with impaired IGF signaling.
Human coronary artery perivascular adipocytes overexpress genes responsible for regulating vascular morphology, inflammation, and hemostasis
Authors: Chatterjee Tapan K. , Aronow Bruce J. , Tong Wilson S. , Manka David , Tang Yaoliang , Bogdanov Vladimir Y. , Unruh Dusten , Blomkalns Andra L. , Piegore Mark G. , Weintraub Daniel S. , Rudich Steven M. , Kuhel David G. , Hui David Y. , Weintraub Neal L.
Published: June 2013

Inflammatory cross talk between perivascular adipose tissue and the blood vessel wall has been proposed to contribute to the pathogenesis of atherosclerosis. We previously reported that human perivascular (PV) adipocytes exhibit a proinflammatory phenotype and less adipogenic differentiation than do subcutaneous (SQ) adipocytes. To gain a global view of the genomic basis of biologic differences between PV and SQ adipocytes, we performed genome-wide expression analyses to identify differentially expressed genes between adipocytes derived from human SQ vs. PV adipose tissues. Although >90% of well-expressed genes were similarly regulated, we identified a signature of 307 differentially expressed genes that were highly enriched for functions associated with the regulation of angiogenesis, vascular morphology, inflammation, and blood clotting. Of the 156 PV upregulated genes, 59 associate with angiogenesis, vascular biology, or inflammation, noteworthy of which include TNFRSF11B (osteoprotegerin), PLAT, TGFB1, THBS2, HIF1A, GATA6, and SERPINE1. Of 166 PV downregulated genes, 21 associated with vascular biology and inflammation, including ANGPT1, ANGPTL1, and VEGFC. Consistent with the emergent hypothesis that PV adipocytes differentially regulate angiogenesis and inflammation, cell culture-derived adipocyte-conditioned media from PV adipocytes strongly enhanced endothelial cell tubulogenesis and monocyte migration compared with media from SQ adipocytes. These findings demonstrate that PV adipocytes have the potential to significantly modulate vascular inflammatory crosstalk in the setting of atherosclerosis by their ability to signal to both endothelial and inflammatory cells.
Role of the Crosstalk between Autophagy and Apoptosis in Cancer
Authors: Su Minfei , Mei Yang , Sinha Sangita
Published: June 2013

Autophagy and apoptosis are catabolic pathways essential for organismal homeostasis. Autophagy is normally a cell-survival pathway involving the degradation and recycling of obsolete, damaged, or harmful macromolecular assemblies; however, excess autophagy has been implicated in type II cell death. Apoptosis is the canonical programmed cell death pathway. Autophagy and apoptosis have now been shown to be interconnected by several molecular nodes of crosstalk, enabling the coordinate regulation of degradation by these pathways. Normally, autophagy and apoptosis are both tumor suppressor pathways. Autophagy fulfils this role as it facilitates the degradation of oncogenic molecules, preventing development of cancers, while apoptosis prevents the survival of cancer cells. Consequently, defective or inadequate levels of either autophagy or apoptosis can lead to cancer. However, autophagy appears to have a dual role in cancer, as it has now been shown that autophagy also facilitates the survival of tumor cells in stress conditions such as hypoxic or low-nutrition environments. Here we review the multiple molecular mechanisms of coordination of autophagy and apoptosis and the role of the proteins involved in this crosstalk in cancer. A comprehensive understanding of the interconnectivity of autophagy and apoptosis is essential for the development of effective cancer therapeutics.
Adsorption Properties and Inhibition of C38 Steel Corrosion in Hydrochloric Solution by Some Indole Derivates: Temperature Effect, Activation Energies, and Thermodynamics of Adsorption
Authors: Lebrini M. , Robert F. , Roos C.
Published: June 2013

The corrosion rates in the presence of some indole derivates, namely, 9H-pyrido[3,4-b]indole (norharmane) and 1-methyl-9H-pyrido[3,4-b]indole (harmane), as inhibitors of C38 steel corrosion inhibitor in 1 M HCl solution, were measured by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques, in the range of temperatures from 25 to 55∘C. Results obtained revealed that the organic compounds investigated have inhibiting properties for all temperatures. The inhibition was assumed to occur via adsorption of the indole molecules on the metal surface. Adsorption of indole derivates was found to follow the Langmuir isotherm. The apparent activation energies, enthalpies, and entropies of the dissolution process and the free energies and enthalpies for the adsorption process were determined by potentiodynamic polarization and electrochemical impedance. The fundamental thermodynamic functions were used to collect important information about indole inhibitory behaviour.
The Effects of Bile Duct Obstruction on Liver Volume: An Experimental Study
Authors: Ertor Bahtiyar , Topaloglu Serdar , Calik Adnan , Cobanoglu Umit , Ahmetoglu Ali , Ak Huseyin , Karabulut Erdem , Arslan Mithat Kerim
Published: June 2013

Objectives.This study is aimed at investigating alterations in liver volume during obstructive jaundice in rat liver.Materials and Methods.Thirty-six rats were divided into four groups. Abdominal tomography was performed for baseline volumetric analyses. The main bile ducts were ligated (BDL). Volumetric analyses were repeated 3 days after BDL in group 1, 7 days after BDL in group 2, 15 days after BDL in group 3, and 25 days after BDL in group 4, and total hepatectomy was performed in all animals. Control group () was created with the rats that died before bile duct ligation.Results.There was no difference found in liver volume in group 1 compared to control animals. The liver volume was increased 7 days after BDL (). It was increased up to 60% of baseline values 25 days after BDL (). Wet liver weights of animals were also increased compared to control group. Liver weights were increased up to 40% percent of baseline values in group 4 ().Conclusions.Liver volume and weight were increased after BDL. Liver surgery in patients with huge liver mass is generally associated with significant difficulty. The surgeon should be aware of the time-dependent alteration in liver volume after obstructive jaundice.
Particle System Based Adaptive Sampling on Spherical Parameter Space to Improve the MDL Method for Construction of Statistical Shape Models
Authors: Xu Rui , Zhou Xiangrong , Hirano Yasushi , Tachibana Rie , Hara Takeshi , Kido Shoji , Fujita Hiroshi
Published: June 2013

Minimum description length (MDL) based group-wise registration was a state-of-the-art method to determine the corresponding points of 3D shapes for the construction of statistical shape models (SSMs). However, it suffered from the problem that determined corresponding points did not uniformly spread on original shapes, since corresponding points were obtained by uniformly sampling the aligned shape on the parameterized space of unit sphere. We proposed a particle-system based method to obtain adaptive sampling positions on the unit sphere to resolve this problem. Here, a set of particles was placed on the unit sphere to construct a particle system whose energy was related to the distortions of parameterized meshes. By minimizing this energy, each particle was moved on the unit sphere. When the system became steady, particles were treated as vertices to build a spherical mesh, which was then relaxed to slightly adjust vertices to obtain optimal sampling-positions. We used 47 cases of (left and right) lungs and 50 cases of livers, (left and right) kidneys, and spleens for evaluations. Experiments showed that the proposed method was able to resolve the problem of the original MDL method, and the proposed method performed better in the generalization and specificity tests.
Synthesis, Crystal Structures, and Magnetic Properties of Ternary M(II)-Dicyanamide-hydroxypyridine Complexes
Authors: Zheng Ling-Ling
Published: June 2013

Three two-dimensional (2D) and 3D supramolecular coordination architectures based on ternary M(II)-dicyanamide-2-hydroxypyridine systems, [Co(hmpH)2(dca)2] (1), [Cu(hmpH)2(dca)2] (2), and [Mn(hepH)2(dca)2] (3) (dca = dicyanamide, hmpH = 2-(hydroxymethyl)pyridine, hepH = 2-(hydroxyethyl)pyridine), have been synthesized. 1 is a mononuclear Co(II) complex. The mononuclear units are interlinked into a 2D (4,4) hydrogen-bonded layer via O–H⋯N hydrogen bonds between the hydroxyl groups and the noncoordinating nitrile ends. These 2D layers are further extended into a 3D supramolecular architecture via the interlayer pyridyl-pyridyl stacking interaction. 2 has a 1D coordination chain structure formed by the double 1,5-dca bridged dinuclear [Cu2(1,5-dca)2(hmpH)2] unit and the 1,3-dca bridges via weak Cu–N coordination, and these 1D coordination chains are further extended into 2D hydrogen-bonded layers via strong O–H⋯N hydrogen-bonding interaction between the hydroxyl groups and the noncoordinating nitrile ends. 3 is a 2D (4,4) coordination network made of 1D [Mn(hepH)(1,5-dca)] helical chain units and interchain double (1,5-dca) bridges. Pairs of [Mn(hepH)(1,5-dca)] helical chains are interlinked by the double (1,5-dca) bridges into a racemic coordination layer structure, which is further extended into a 3D hydrogen-bonded network. Magnetic studies reveal that weak antiferromagnetic exchange occurs in 3.
Statistical Inferences and Applications of the Half Exponential Power Distribution
Authors: Gui Wenhao
Published: June 2013

We investigate the statistical inferences and applications of the half exponential power distribution for the first time. The proposed model defined on the nonnegative reals extends the half normal distribution and is more flexible. The characterizations and properties involving moments and some measures based on moments of this distribution are derived. The inference aspects using methods of moment and maximum likelihood are presented. We also study the performance of the estimators using the Monte Carlo simulation. Finally, we illustrate it with two real applications.