bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective extraction of Hf(IV) over Zr(IV) from aqueous H2SO4 solutions by solvent extraction with acidic organophosphorous based extractants
Authors: Banda Raju , Min Soo Hwan , Lee Man Seung
Published: October 2013

BACKGROUND

The present paper describes the selective extraction of Hf(IV) over Zr(IV) using two acidic extractants (D2EHPA and Cyanex 272) and its mixture with LIX 63 from sulphate medium. To achieve this, extractant and H2SO4 concentrations were varied and results obtained.

RESULTS

Selective extraction of Hf(IV) over Zr(IV) was possible using D2EHPA/or Cyanex 272 at 2 mol L‐1 and higher H2SO4 solutions. For all investigated experimental conditions, D2EHPA exhibited greater efficiency than Cyanex 272 for the extraction of Hf(IV). Compared with either D2EHPA or Cyanex 272 alone, binary extractant mixtures (D2EHPA+LIX 63, Cyanex 272+LIX 63) did not show much selectivity towards the extraction of Hf(IV) over Zr(IV). Extraction with D2EHPA at 4 mol L‐1 H2SO4 solution led to a separation factor around 30 between Hf(IV) and Zr(IV).

CONCLUSIONS

Hf(IV) was selectively extracted over Zr(IV) in the investigated systems, with a good separation factor. Results indicated the possibility of separating the metal ions by selective extraction of Hf(IV). The selective extraction of Hf(IV) is important and advantages in separation give the potential for application in nuclear science and technology. © 2013 Society of Chemical Industry
Remarks on Leray's self‐similar solutions to the 3D magnetohydrodynamic equations
Authors: Benbernou Samia , Ragusa Maria Alessandra , Terbeche Mekki
Published: October 2013

In this note, we examine small self‐similar solutions of the 3D incompressible magnetohydrodynamic equations in homogenous function spaces and show the uniqueness of self‐similar solutions when the velocity field is small in some homogeneous function spaces. This extend the recent results given by C. He and Z. Xin. “On the self‐similar solutions of the magneto‐hydro‐dynamic equations. Acta Mathematica Scientia, série B English Edition 2009; 29 (3): 583–598”. It is a natural way to extend the space widely and improve the previous results. Copyright © 2013 John Wiley & Sons, Ltd.
Quantification of human lung structure and physiology using hyperpolarized 129Xe
Authors: Chang Yulin V. , Quirk James D. , Ruset Iulian C. , Atkinson Jeffrey J. , Hersman F. William , Woods Jason C.
Published: October 2013

Purpose

To present in vivo, human validation of a previously proposed method to measure key pulmonary parameters related to lung microstructure and physiology. Some parameters, such as blood–air barrier thickness, cannot be measured readily by any other noninvasive modality.

Methods

Healthy volunteers (n = 12) were studied in 1.5T and 3T whole body human scanners using hyperpolarized xenon. Xenon uptake by lung parenchyma and blood was measured using a chemical shift saturation recovery sequence. Both dissolved‐xenon peaks at 197 ppm and 217–218 ppm were fitted against a model of xenon exchange (MOXE) as functions of exchange time. Parameters related to lung function and structure can be obtained by fitting to this model.

Results

The following results were obtained from xenon uptake (averaged over all healthy volunteers): surface‐area‐to‐volume ratio = 210 ± 50 cm−1; total septal wall thickness = 9.2 ± 6.5 μm; blood‐air barrier thickness = 1.0 ± 0.3 μm; hematocrit = 27 ± 4%; pulmonary capillary blood transit time = 1.3 ± 0.3 s, in good agreement with literature values from invasive experiments. More detailed fitting results are listed in the text.

Conclusion

The initial in vivo human results demonstrate that our proposed methods can be used to noninvasively determine lung physiology by simultaneous quantification of a few important pulmonary parameters. This method is highly promising to become a versatile screening method for lung diseases. Magn Reson Med 71:339–344, 2014. © 2013 Wiley Periodicals, Inc.
Macromolecular and supramolecular chirality: a twist in the polymer tales
Authors: de Bruin Alexander G , Barbour Michele E , Briscoe Wuge H
Published: October 2013

Significant advances have been made recently in generating chiral polymer surfaces and materials using a range of methods such as block copolymer self‐assembly, layer‐by‐layer assembly and surface functionalization by polymer brushes. This paves the way for novel chiral materials that can harness and tailor chiral interactions for specific functionalities and properties in a range of biomedical and bioanalytical applications. This paper reviews these advances and speculates on the future of chiral surfaces. © 2013 Society of Chemical Industry
On the joint use of propensity and prognostic scores in estimation of the average treatment effect on the treated: a simulation study
Authors: Leacy Finbarr P. , Stuart Elizabeth A.
Published: October 2013

Propensity and prognostic score methods seek to improve the quality of causal inference in non‐randomized or observational studies by replicating the conditions found in a controlled experiment, at least with respect to observed characteristics. Propensity scores model receipt of the treatment of interest; prognostic scores model the potential outcome under a single treatment condition. While the popularity of propensity score methods continues to grow, prognostic score methods and methods combining propensity and prognostic scores have thus far received little attention. To this end, we performed a simulation study that compared subclassification and full matching on a single estimated propensity or prognostic score with three approaches combining the estimated propensity and prognostic scores: full matching on a Mahalanobis distance combining the estimated propensity and prognostic scores (FULL–MAHAL); full matching on the estimated prognostic propensity score within propensity score calipers (FULL–PGPPTY); and subclassification on an estimated propensity and prognostic score grid with 5 × 5 subclasses (SUBCLASS(5*5)). We considered settings in which one, both, or neither score model was misspecified. The data generating mechanisms varied in the degree of linearity and additivity in the true treatment assignment and outcome models. FULL–MAHAL and FULL–PGPPTY exhibited strong to superior performance in root mean square error terms across all simulation settings and scenarios. Methods combining propensity and prognostic scores were no less robust to model misspecification than single‐score methods even when both score models were incorrectly specified. Our findings support the joint use of propensity and prognostic scores in estimation of the average treatment effect on the treated. Copyright © 2013 John Wiley & Sons, Ltd.
A Genetic Counselor's Guide to Using Next‐Generation Sequencing in Clinical Practice
Authors: Facio Flavia M. , Lee Kristy , O'Daniel Julianne M.
Published: October 2013

Advances in next‐generation sequencing (NGS) and rapid reductions in cost have increased the use of such technologies in research and clinical practice. However, many barriers exist to translating NGS for routine clinical use, including issues related to the interpretation of results, and the potential to find results that are secondary or incidental to the specific application of NGS. Nonetheless, NGS has become sufficiently affordable to be offered by several clinical laboratories, and increasingly it is becoming an attractive and viable option for clinicians and patients. This article reviews current NGS technologies, highlighting the information genetic counselors need to know to make informed‐decisions about utilizing NGS in the clinic, and underscoring the impact of this new testing modality on the practice of genetic counseling.
Application of metal triflate catalysts for the trans‐esterification of Jatropha curcas L. oil with methanol and higher alcohols
Authors: Daniel Louis , Rasrendra Carolus B. , Kloekhorst Arjan , Broekhuis Antonius A. , Manurung Robert , Heeres Hero J.
Published: October 2013

This paper describes an experimental study on the application of metal triflate salts for the (trans‐) esterification of fatty esters (triolein, methyl oleate, methyl linoleate), fatty acid (oleic acid), as well as Jatropha curcas L. oil with methanol and higher alcohols (ethanol, n‐propanol, iso‐propanol, iso‐butanol, tert‐butanol). The effect of the metal type (scandium, bismuth, aluminium, lanthanum, copper, zinc) and process conditions on reaction performance were evaluated. Highest conversions were obtained with Al(OTf)3. Reaction of triolein with methanol gave 99 mol% conversion at 165 °C for 1 h and the main product was the methyl ester. In addition, partial methoxylation of the carbon–carbon double bonds in the fatty acid chains was observed, though their fraction in the mixture was less than 20 mol%. The trans‐esterification reaction was also successfully performed using higher alcohols, giving >95 % conversions for ethanol, n‐propanol, iso‐propanol and iso‐butanol, whereas tert‐butanol was not reactive. For the reaction of oleic acid with methanol, quantitative esterification, partial methoxylation of the carbon–carbon double bonds and the formation of small amounts of a lactone was observed. The methodology using Al(OTf)3 was successfully performed on the trans‐esterification reaction of JO (FFA content of 2.1 wt%) with various alcohols. Key properties (viscosity, pour point and cloud points) of the (branched) Jatropha esters were determined. The best cold‐flow properties were obtained for the iso‐propyl esters of JO, with cloud point and pour point of −3 and −24 °C, respectively.
Checkpoint blocking antibodies in cancer immunotherapy
Authors: Kyi Chrisann , Postow Michael A.
Published: October 2013

Cancers can be recognized by the immune system, and the immune system may regulate and even eliminate tumors. The development of checkpoint blocking antibodies, such as those directed against cytotoxic T‐lymphocyte antigen 4 (CTLA‐4) and programmed death 1 receptor (PD‐1), have demonstrated significant recent promise in the treatment of an expanding list of malignancies. While both CTLA‐4 and PD‐1 function as negative regulators, each plays a non‐redundant role in modulating immune responses. CTLA‐4 attenuates the early activation of naïve and memory T cells. In contrast, PD‐1 is primarily involved in modulating T cell activity in peripheral tissues via interaction with its ligands, PD‐L1 and PD‐L2. Unfortunately, not all patients respond to these therapies, and evaluation of biomarkers associated with clinical outcomes is ongoing. This review will examine the efficacy, toxicities, and clinical development of checkpoint blocking antibodies, including agents already approved by the US Food and Drug Administration (anti‐CTLA‐4, ipilimumab) or in development (anti‐PD‐1, PD‐L1). Future studies will likely uncover new promising immunologic checkpoints to target alone or in combination with other immunotherapeutic approaches, chemotherapy, radiotherapy, and small molecules.
Diagnostic Accuracy Studies in Mild Traumatic Brain Injury: A Systematic Review and Descriptive Analysis of Published Evidence
Authors: Pape Theresa L.‐B. , High Walter M. , St. Andre Justin , Evans Charlesnika , Smith Bridget , Shandera‐Ochsner Anne L. , Wingo Jana , Moallem Isabelle , Baldassarre Megan , Babcock‐Parziale Judi
Published: October 2013

Objectives

To synthesize evidence and report findings from a systematic search and descriptive analysis of peer‐reviewed published evidence of the accuracy of tests used for diagnosing mild traumatic brain injury (mTBI). The article also summarizes points of concurrence and divergence regarding case definitions of mTBI identified during the review.

Type

Systematic review and descriptive analysis of published evidence.

Literature Survey

A search of PubMed, PsychInfo, and the Cochrane Library for peer‐reviewed publications between 1990 and July 6, 2011, identified 1218 abstracts; 277 articles were identified for full review, and 13 articles met the criteria for evaluation.

Methodology

Manuscript inclusion criteria were (1) reported sensitivity (Se) and specificity (Sp), or reported data were sufficient to compute Se and Sp; (2) >1 participant in the study; (3) at least 80% of the study cohort was ≥18 years of age; and (4) written in English. Articles describing clinical practice guidelines, opinions, theories, or clinical protocols were excluded. Seven investigators independently evaluated each article according to the Standards for Reporting of Diagnostic Accuracy (STARD) criteria.

Synthesis

Findings indicate that all 13 studies involved civilian noncombat populations. In 7 studies, authors examined acute mTBI, and in 4 studies, historical remote mTBI was examined. In the 13 studies, Se ranged from 13%‐92% and Sp ranged from 72%‐99%, but confidence in these findings is problematic because the STARD review indicates opportunities for bias in each study.

Conclusions

Findings indicate that no well‐defined definition or clinical diagnostic criteria exist for mTBI and that diagnostic accuracy is currently insufficient for discriminating between mTBI and co‐occurring mental health conditions for acute and historic mTBI. Findings highlight the need for research examining the diagnostic accuracy for acute and historic mTBI.
On the highest non-breaking wave in a group: fully nonlinear water wave breathers versus weakly nonlinear theory
Authors: Slunyaev Alexey V. , Shrira Victor I.
Published: October 2013

In nature, water waves usually propagate in groups and the open question about the characteristics of the highest possible wave in a group is of significant theoretical and practical interest. We examine the problem of the highest non-breaking wave in a wave group by direct numerical simulations of the exact Euler equations. The main aim of the study is twofold: (i) to describe the highest wave in a group in fully nonlinear setting and find its dependence on parameters; (ii) to examine correspondence between the exact breather solutions of weakly nonlinear analytic theory based on the integrable nonlinear Schrödinger (NLS) equation and their strongly nonlinear analogues. In contrast to weakly nonlinear models the very notion of the highest wave is ill-defined: the maximal crest elevation, the maximal trough-to-crest height and the deepest trough all occur at close but different moments; correspondingly, we have to speak about distinctively different extreme waves. In the simulations small initial perturbation of a uniform wave train were prescribed in a way ensuring that the initial perturbation excites a single breather-type modulation. The ensuing growth results in higher wave magnitudes and takes longer time to develop compared with the NLS theory. The maxima of crest elevation noticeably exceed their weakly nonlinear analogues. The wave with the highest crest differs significantly from the unmodulated wave: the local wavelength contracts considerably, the crest becomes noticeably higher; the vicinity of the crest of such an extreme wave is close to that of the limiting Stokes periodic wave. Thus, the shape of the maximal crest wave is almost universal, i.e. it practically does not depend on the way the wave group evolved, or even whether there was initially more than one group. The evolution of a single NLS breather has been shown to have a qualitatively similar but quantitatively quite different analogue in the fully nonlinear setting. The one-to-one mapping of the NLS breather solutions onto fully nonlinear ones has been constructed. The fully nonlinear breathers are found to be robust, which provides grounds for applying the results for developing short-term deterministic forecasting of rogue waves.
Effects of foliar-applied nitrogen fertilizer on oilseed rape (Brassica napus)
Authors: WHITE C. A. , ROQUES S. E. , BERRY P. M.
Published: October 2013

The aim of the present study was to evaluate the effects on yield, oil concentration and nitrogen (N) uptake efficiency of N fertilizer applied to the foliage of oilseed rape during and soon after flowering. Four field experiments were conducted in the UK during the 2008/09 and 2009/10 seasons which investigated six rates of soil-applied N (ammonium nitrate) ranging from 0 to 280 or 320 kg N/ha with each treatment followed by 0 or 40 kg/ha of foliar N applied as a solution of urea at the end of flowering. Each experiment also investigated five rates of foliar N ranging from 0 to 120 kg N/ha applied at the end of flowering and five timings of foliar N (40 kg N/ha) from mid-flowering to 2 weeks after the end of flowering.

Foliar N at 40 kg N/ha applied at the end of flowering significantly increased the seed yield in three of the four experiments. The seed yield increase across all four experiments was 0·25 t/ha (range of 0–0·41 t/ha). In two experiments, the increase in seed yield in response to foliar N occurred irrespective of whether it followed sub-optimal or super-optimal rates of soil-applied N; in one experiment there was a greater response at sub-optimal soil-applied N rates. The foliar N treatment reduced the seed oil concentration by 11 g/kg and increased seed protein concentration by 11 g/kg. Similar yield responses were observed for foliar N applications between mid-flowering and 2 weeks after the end of flowering. The efficiency with which foliar N was taken up into the plant varied between 0 and 100% with an average uptake efficiency across the four experiments of 61%.
Nuclear Powers' Disarmament Obligation under the Treaty on the Non-Proliferation of Nuclear Weapons and the Comprehensive Nuclear Test Ban Treaty: Interactions between Soft Law and Hard Law
Authors: PIETROBON ALESSANDRA
Published: October 2013

The Comprehensive Nuclear Test Ban Treaty (CTBT) will not be effective until all the 44 states listed in its Annex 2 ratify it. A special link has been established between the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the CTBT. The disarmament obligation set by Article VI of the NPT, which has not yet been complied with, remains highly controversial. The relevant subsequent practice of the states parties to the NPT shows that the ratification of the CTBT is to be considered the first of the practical steps towards compliance with Article VI. However, as the practical steps do not set any legally binding norms, there is no legal obligation to ratify the CTBT, not even for the 44 states listed in Annex 2 whose ratification is essential. The paper deals with the position of nuclear powers party to the NPT that have not yet ratified the CTBT (most prominently the US and China) and demonstrates that these states should at least provide detailed motivation for their conduct. Otherwise, other states parties to the NPT could consider them as not complying in good faith with Article VI of the NPT and invoke theinadimplenti non est ademplendumrule to justify breaches of their own obligations under the same treaty.
S100A7 in the Fallopian tube: a comparative study
Authors: Teijeiro Juan M , Marini Patricia E.
Published: October 2013

The oviduct is a dynamic organ in which final gamete maturation, fertilization and early embryo development take place. It is considered to be a sterile site; however the mechanism for sterility maintenance is still unknown. S100A7 is an anti-microbial peptide that has been reported in human reproductive tissues such as prostate, testicle, ovary, normal cervical epithelium and sperm. The current work reports the presence of S100A7 in the Fallopian tube and its localization at the apical surface of epithelial cells. For comparison, porcine S100A7 was used for antibody development and search for peptide in reproductive tissues. Although present in boar seminal vesicles and seminal plasma, S100A7 was not detected on female porcine organs. Also, in contrast with the human protein, porcine S100A7 did not show anti-microbial activity under the conditions tested. Phylogenetic analyses showed high divergence of porcine S100A7 from human, primate, bovine, ovine and equine sequences, being the murine sequence at a most distant branch. The differences in sequence homology, Escherichia coli-cidal activity, detectable presence and localization of S100A7 from human and pig, suggest that there are possible different functions in each organism.
TRYING TO DEFEND ATTEMPTS: REPLIES TO BRATMAN, BRINK, ALEXANDER, AND MOORE
Authors: Yaffe Gideon
Published: October 2013

This essay replies to the thoughtful commentaries, by Michael Bratman, David Brink, Larry Alexander, and Michael Moore, on my book Attempts.
YAFFE ON CRIMINAL ATTEMPTS
Authors: Bratman Michael E.
Published: October 2013

Central to Gideon Yaffe's powerful theory of the legitimate criminalization of unsuccessful attempts is his “transfer principle,” according to which, “if a particular form of conduct is legitimately criminalized, then the attempt to engage in that form of conduct is also legitimately criminalized.” I argue that this principle, taken together with Yaffe's theory of the nature of attempts, threatens to lead to a normatively problematic conclusion in support of the legitimate criminalization of attempts that are merely a matter of thinking and do not involve action in the public space. And I argue that Yaffe's efforts to block this conclusion are themselves problematic. This leads to a proposed revision of the “transfer principle,” one that draws on plausible normative views about the nonlegitimacy of criminal sanctions in cases of attempts that are merely a matter of thinking and do not involve action in the public space.
ARE UNIT ROOT TESTS USEFUL IN THE DEBATE OVER THE (NON)STATIONARITY OF HOURS WORKED?
Authors: Charles Amélie , Darné Olivier , Tripier Fabien
Published: October 2013

The performance of unit root tests on simulated series is compared, using the business-cycle model of Chang et al. [Journal of Money, Credit and Banking39(6), 1357–1373 (2007)] as a data-generating process. Overall, Monte Carlo simulations show that the efficient unit root tests of Ng and Perron (NP) [Econometrica69(6), 1519–1554 (2001)] are more powerful than the standard unit root tests. These efficient tests are frequently able (i) to reject the unit-root hypothesis on simulated series, using the best specification of the business-cycle model found by Chang et al., in which hours worked are stationary with adjustment costs, and (ii) to reduce the gap between the theoretical impulse response functions and those estimated with a Structural VAR model. The results of Monte Carlo simulations show that the hump-shaped behavior of data can explain the divergence between unit root tests.
Will the damage be done before we feel the heat? Infectious disease emergence and human response
Authors: Kock R. A.
Published: October 2013

The global political economy is facing extreme challenges against a backdrop of large-scale expansion of human and domestic animal populations and related impacts on the biosphere. Significant global socio-ecological changes have occurred in the period of a single lifetime, driven by increased technology and access to physical and biological resources through open markets and globalization. Current resource consumption rates are not sustainable and ecological tipping points are being reached and one of the indicators of these may be a changing balance between hosts and pathogens. A period of extraordinary progress in reducing infection risk and disease impact on humans and domestic animals in the 20th Century is reversing in the 21st, but not always and not everywhere. Drivers for this shift are discussed in terms of demographics, agroecology, biodiversity decline and loss of resilience in ecosystems, climate change and increasing interconnectedness between species globally. Causality of disease emergence remains highly speculative, but patterns and data are emerging to commend a precautionary approach, while reassessing our global political, social and economic systems.
The climate change–infectious disease nexus: is it time for climate change syndemics?
Authors: Heffernan Claire
Published: October 2013

Conceptualizing climate as a distinct variable limits our understanding of the synergies and interactions between climate change and the range of abiotic and biotic factors, which influence animal health. Frameworks such as eco-epidemiology and the epi-systems approach, while more holistic, view climate and climate change as one of many discreet drivers of disease. Here, I argue for a new paradigmatic framework: climate-change syndemics. Climate-change syndemics begins from the assumption that climate change is one of many potential influences on infectious disease processes, but crucially is unlikely to act independently or in isolation; and as such, it is the inter-relationship between factors that take primacy in explorations of infectious disease and climate change. Equally importantly, as climate change will impact a wide range of diseases, the frame of analysis is at the collective rather than individual level (for both human and animal infectious disease) across populations.
Discovery and Development of Ganetespib
Authors: Ying Weiwen
Published: October 2013

Ganetespib is a potent second-generation inhibitor of heat-shock protein 90 (Hsp90), structurally consisting of a resorcinol moiety and a triazolone core. Ganetespib has shown robust anticancer activity against a broad variety of tumor cell lines where exposure resulted in the degradation of many well-known Hsp90 client proteins. In solid and hematological xenograft models of oncogene addiction, ganetespib has demonstrated potent antitumor efficacy both as a single agent and in combination with a number of widely used cancer therapeutics. Evaluation of the microregional activity of ganetespib in tumor xenografts showed that ganetespib efficiently distributed throughout tumor tissue, including hypoxic regions >150 μm from the microvasculature, to inhibit proliferation and induce apoptosis. Pre-clinical results with ganetespib have shown a reduction of levels of hypoxia induced factor-1alpha (HIF-1α), suggesting that the compound can reduce or disrupt new blood vessel formation (angiogenesis) and the emergence of new lesions (metastases). Ganetespib possesses an excellent safety profile and shows no evidence of cardiac, liver or ocular toxicity. Ganetespib is being evaluated in a number of clinical trials including lung and breast cancers. In a Phase IIb global, randomized, multi-center study of ganetespib in combination with docetaxel in lung adenocarcinoma patients, a favorable safety profile as well as meaningful improvements in overall survival have been observed. Noteworthy clinical benefits have also been seen in additional clinical trials using ganetespib as monotherapy.
The Cancer Super-chaperone Hsp90: Drug Targeting and Post-translational Regulation
Authors: Walton-Diaz Annerleim , Khan Sahar , Trepel Jane B. , Mollapour Mehdi , Neckers Len
Published: October 2013

Molecular chaperones, as the name suggests, are involved in folding, maintenance, intracellular transport and degradation of proteins as well as in facilitating cell signaling. Heat-shock protein 90 (Hsp90) is an essential eukaryotic molecular chaperone that carries out these processes in normal and cancer cells. Hsp90 function in vivo is coupled to its ability to hydrolyze ATP and this can be regulated by co-chaperones and post-translational modifications. In this review, we explore the varied roles of known post-translational modifications of Hsp90 (phosphorylation, acetylation, S-nitrosylation, oxidation and ubiquitination) in fine-tuning chaperone function in eukaryotes. We also provide examples of Hsp90 inhibitor-based clinical activity in several molecularly distinct cancers and we use these examples to suggest how and in what cancers Hsp90 inhibitors are most likely to be effective, either as single agents or in combination with additional therapies.
Heat-shock Protein 90 as an Antimalarial Target
Authors: Rochani Ankit K. , Singh Meetali , Tatu Utpal
Published: October 2013

Malaria is a communicable infectious disease that has affected many tropical countries. Fighting malaria has been a major socio-economic problem. In spite of more than a century old fight against the infection, today we have only six highly potent scaffolds that provide therapeutic solutions for malaria. Generics of these molecules have been made available to provide healthcare support to endemic regions but the resistance to these drugs has been emerging simultaneously. Hence malaria has become a priority disease in the healthcare segment. It is observed that during the malaria infection combating stress is the primary requirement of the Plasmodium parasite. One of the molecular chaperones, namely heat-shock protein 90 (Hsp90), helps the parasite to cope with this stress response and this ultimately helps in establishing infection. Inhibition of this molecular chaperone causes stage-specific arrest in parasite growth. This chapter sheds light on the path of discovery of PfHsp90 as novel drug target for malaria and approaches for development of PfHsp90-targeted antimalarial therapy.
Sign subband adaptive filter with ℓ1‐norm minimisation‐based variable step‐size
Authors: Kim J.H. , Chang J.‐H. , Nam S.W.
Published: October 2013

A new variable step‐size sign subband adaptive filter (VSS‐SSAF), not requiring any a priori information, is proposed by minimising the ℓ1‐norm of the subband a posteriori error under a box‐constraint on the step‐size. In addition, an efficient numerical procedure for updating its VSS is introduced to solve the non‐differentiable convex problem. The proposed algorithm provides comparable or better convergence performance, when compared with the recent VSS‐SSAF (minimising the mean‐squares deviation with a priori knowledge of noise variance) or other conventional algorithms aimed at robustness against impulsive interferences.
On tuning FO[PI] controllers for FOPDT processes
Authors: Badri V. , Tavazoei M.S.
Published: October 2013

A method recently proposed for tuning fractional order [proportional integral] (FO[PI]) controllers is investigated. This tuning method, when applied in control of first‐order plus dead time (FOPDT) processes, can ensure the desired phase margin, the desired gain crossover frequency and the flatness of the phase Bode plot at such a frequency. The necessary and sufficient condition for the applicability of the aforementioned tuning method is derived. Also, it is shown that this condition can be used in obtaining the achievable performance region of the tuning method in the gain crossover frequency‐phase margin plane.
Adaptive region matching for region‐based image retrieval by constructing region importance index
Authors: Yang Xiaohui , Cai Lijun
Published: October 2013

This study deals with the problem of similarity matching in region‐based image retrieval (RBIR). A novel visual similarity measurement called adaptive region matching (ARM) has been developed. For decreasing negative influence of interference regions and important information loss simultaneously, a region importance index is constructed and semantic meaningful region (SMR) is introduced. Moreover, ARM automatically performs SMR‐to‐image matching or image‐to‐image matching. Extensive experiments on Corel‐1000, Caltech‐256 and University of Washington (UW) databases demonstrate the authors proposed ARM is more flexible and more efficient than the existing visual similarity measurements that were originally developed for RBIR.
Pulse‐coupled neural network feature generation model for Arabic sign language recognition
Authors: SamirElons Ahmed , Abull‐ela Magdy , Tolba Mohamed F.
Published: October 2013

Many feature generation methods have been developed for object recognition. Some of these methods succeeded in achieving invariance against object translation, rotation and scaling but faced problems of the bright background effect and non‐uniform light on the quality of the generated features. This problem has hindered recognition systems from working in a free environment. This paper proposes a new method to enhance the feature quality based on pulse‐coupled neural network. An adaptive model that defines continuity factor is proposed as a weight factor of the current pulse in signature generation process. The proposed new method has been employed in a hybrid feature extraction model that is followed by a classifier and was applied and tested in Arabic sign language static hand posture recognition; the superiority of the new method is shown.
Difference theoretic feature set for scale‐, illumination‐ and rotation‐invariant texture classification
Authors: Susan Seba , Hanmandlu Madasu
Published: October 2013

Texture identification and classification under varying scale, rotation and illumination conditions is a challenging task in pattern recognition and grey level difference statistics have been extensively used for this purpose. This study presents a new set of features for scale‐, rotation‐ and illumination‐invariant texture classification derived from the correlated distributions of local and global grey level differences of intensities in the texture image. The authors analyse the terms in the correlation formula for determining the difference‐based feature set that is invariant and unique for a texture class. A comprehensive evaluation is performed on a huge database of digitally created texture samples of varying scale, orientation and brightness. The one‐nearest neighbour classifier is used in the authors’ experiments and the results indicate high classification accuracy for the proposed feature vector under varying scale, rotation and brightness conditions. The proposed method is compared with the highly efficient rotation‐ and illumination‐invariant local binary pattern (LBP) and LBP variance techniques and the scale‐ and rotation‐invariant MRS4 technique and is found superior in performance with an additional advantage of reduced feature dimension.
Efficient wavelet‐based perceptual watermark masking for robust fingerprint image watermarking
Authors: Zebbiche Khalil , Khelifi Fouad
Published: October 2013

In this study, a robust wavelet‐based fingerprint image watermarking scheme using an efficient just perceptual weighting (JPW) model has been proposed. The JPW model exploits three human visual system characteristics, namely: spatial frequency sensitivity, local brightness masking and texture masking, to compute a weight for each wavelet coefficient, which is then used to control the amplitude of the inserted watermark. The idea is motivated by the fact that fingerprint images perceptually differ from natural images and a JPW model adapted to such images would further enhance the robustness of the watermarking scheme. Experimental results show that the proposed model significantly improves the performance of the conventional watermarking technique in terms of robustness while maintaining the same imperceptibility of the watermark. Finally, the proposed technique has shown a clear superiority over a number of related state‐of‐the‐art masking techniques.
Cutoff wavenumbers of eccentric circular metallic waveguides
Authors: Kotsis Aristides D. , Roumeliotis John A.
Published: October 2013

Cutoff wavenumbers knm are determined analytically for an eccentric circular metallic waveguide. Separation of variables technique is used for the solution. For small eccentricities kd, where d is the distance between the axes of the cylinders, cosine and sine laws are used instead of the translational addition theorem, in order to satisfy the boundary conditions at the surface of the outer cylinder. Keeping terms up to the order (kd)2 exact, analytical expressions of the form knm(d) = knm(0)[1 + gnm(knmd)2 + O(knmd)4] are obtained for the cutoff wavenumbers of the waveguides, where knm(0) corresponds to the coaxial geometry, with d = 0. Both transverse magnetic and transverse electric modes are considered. Numerical results are given for all types of modes and for various values of the parameters. The method used here is an alternative of the one using the translational addition theorem, in the case of small eccentricities.
Doppler frequency estimation‐based handover algorithm for long‐term evolution networks
Authors: Altrad Omar , Muhaidat Sami , Yoo Paul D
Published: October 2013

Mobile cellular radio systems have become complex multi‐layered systems with a mixed architecture of macro and micro cells; therefore, a dynamic method of triggering the handover algorithm in such systems is invaluable and required. In this paper the authors develop a simple handover mechanism to adapt for a fast moving mobile station requesting a handover, in which the authors utilise a Doppler frequency estimation in the downlink for adjustment and apply it to a long‐term evolution (LTE) network. This method is beneficial for high speed mobiles in macro and/or micro cells, in which for the latter the cell radius is small and needs a dynamic algorithm to respond in a timely manner. The main objective of this study is to investigate the performance of the proposed algorithm; hence, a system layout is specifically designed for this study. Other factors, such as interference, which may affect the performance of the suggested system are not addressed here. The main concern is to study and compare the proposed algorithm to the standard handover algorithm currently implemented in LTE. Simulations at the system level show a marked decrease in the average number of handovers requested.
Simple procedure for optimal sizing and location of a single photovoltaic generator on radial distribution feeder
Authors: Al‐Sabounchi Ammar , Gow John , Al‐Akaidi Marwan
Published: October 2013

Unlike traditional distribution generation (DG) units, the production of photovoltaic DG (PVDG) units is non‐dispatchable and largely driven by the rates of solar irradiance fall on its PV array. In this work, a suitable procedure for optimal sizing and location of single PVDGs on radial distribution feeders has been developed. It goes along with the current trend of interfacing renewable energy generators with the grid due to global warming concern. The procedure applies single PVDG unit at points on the feeder while allowing reverse power flow (RPF) within the feeder line sections. The optimisation objective is to minimise the accumulated line power loss over the day (line energy loss) along the feeder, while keeping the voltage profile along the feeder within permissible limits. A method has been applied to rate the line energy loss considering one time interval, namely feasible optimisation interval. The procedure has been applied to an actual 11 kV feeder in Abu Dhabi city. The application showed obvious benefits in terms of line loss reduction and improvement of the voltage profile. The procedures also resulted in alternative feasible solutions in case the optimal solution cannot be applied for any reason – like inconvenience/limitation of land or investment.
Development of the ion source for cluster implantation
Authors: Kulevoy T. V. , Seleznev D. N. , Kozlov A. V. , Kuibeda R. P. , Kropachev G. N. , Alexeyenko O. V. , Dugin S. N. , Oks E. M. , Gushenets V. I. , Hershcovitch A. , Jonson B. , Poole H. J.
Published: October 2013

Bernas ion source development to meet needs of 100s of electron-volt ion implanters for shallow junction production is in progress in Institute for Theoretical and Experimental Physics. The ion sources provides high intensity ion beam of boron clusters under self-cleaning operation mode. The last progress with ion source operation is presented. The mechanism of self-cleaning procedure is described.
Accurate and efficient integration for molecular dynamics simulations at constant temperature and pressure
Authors: Lippert Ross A. , Predescu Cristian , Ierardi Douglas J. , Mackenzie Kenneth M. , Eastwood Michael P. , Dror Ron O. , Shaw David E.
Published: October 2013

In molecular dynamics simulations, control over temperature and pressure is typically achieved by augmenting the original system with additional dynamical variables to create a thermostat and a barostat, respectively. These variables generally evolve on timescales much longer than those of particle motion, but typical integrator implementations update the additional variables along with the particle positions and momenta at each time step. We present a framework that replaces the traditional integration procedure with separate barostat, thermostat, and Newtonian particle motion updates, allowing thermostat and barostat updates to be applied infrequently. Such infrequent updates provide a particularly substantial performance advantage for simulations parallelized across many computer processors, because thermostat and barostat updates typically require communication among all processors. Infrequent updates can also improve accuracy by alleviating certain sources of error associated with limited-precision arithmetic. In addition, separating the barostat, thermostat, and particle motion update steps reduces certain truncation errors, bringing the time-average pressure closer to its target value. Finally, this framework, which we have implemented on both general-purpose and special-purpose hardware, reduces software complexity and improves software modularity.
Oscillatory instability and fluid patterns in low-Prandtl-number Rayleigh-Bénard convection with uniform rotation
Authors: Pharasi Hirdesh K. , Kumar Krishna
Published: October 2013

We present the results of direct numerical simulations of flow patterns in a low-Prandtl-number (Pr = 0.1) fluid above the onset of oscillatory convection in a Rayleigh-Bénard system rotating uniformly about a vertical axis. Simulations were carried out in a periodic box with thermally conducting and stress-free top and bottom surfaces. We considered a rectangular box (Lx × Ly × 1) and a wide range of Taylor numbers (750 ⩽ Ta ⩽ 5000) for the purpose. The horizontal aspect ratio η = Ly/Lx of the box was varied from 0.5 to 10. The primary instability appeared in the form of two-dimensional standing waves for shorter boxes (0.5 ⩽ η < 1 and 1 < η < 2). The flow patterns observed in boxes with η = 1 and η = 2 were different from those with η < 1 and 1 < η < 2. We observed a competition between two sets of mutually perpendicular rolls at the primary instability in a square cell (η = 1) for Ta < 2700, but observed a set of parallel rolls in the form of standing waves for Ta ⩾ 2700. The three-dimensional convection was temporally quasiperiodic for 750 ⩽ Ta ⩽ 1114, chaotic for 1115 ⩽ Ta < 1125, and quasiperiodic once again for 1125 ⩽ Ta < 2700. The three-dimensional quasiperiodic flow bifurcated into a two-dimensional periodic flow for Ta ⩾ 2700. The convection at the primary instability were three-dimensional and quasiperiodic in time for all values of Ta (⩽3000) in a box with η = 2. Küppers-Lortz type of convection was observed at the primary instability in longer boxes (4 ⩽ η ⩽ 10). The convective structures consisted of the appearance and disappearance of straight rolls, rhombic patterns, and wavy rolls inclined at an angle \documentclass[12pt]{minimal}\begin{document}$\phi = \frac{\pi }{2} - \arctan {(\eta ^{-1})}$\end{document}ϕ=π2−arctan(η−1) with the straight rolls. We also present a low-dimensional model constructed for a square box (η = 1).
Design of the plasma chamber and beam extraction system for SC ECRIS of RAON accelerator
Authors: Kim Y. , Choi S. , Hong I. S.
Published: October 2013

The RAON accelerator is the heavy ion accelerator being built in Korea. It contains a 3rd generation SC ECRIS which uses 28 GHz/18 GHz microwave power to extract 12 puA uranium ion beams. A plasma chamber for that ECRIS is made of aluminum machined from bulk Al. That chamber contains cooling channels to remove dumped power and another access port for microwave introduction and plasma diagnostics. Beam extraction electrodes were designed considering the engineering issues and preliminary beam extraction analysis was done. That plasma chamber will be assembled with a cryostat, and beam extraction experiment will be done.
Dielectric relaxation of long-chain glass-forming monohydroxy alcohols
Authors: Gao Yanqin , Tu Wenkang , Chen Zeming , Tian Yongjun , Liu Riping , Wang Li-Min
Published: October 2013

The dielectric relaxation of two long-chain glass forming monohydroxy alcohols, 2-butyl-1-octanol and 2-hexyl-1-decanol, is studied at low temperature. Remarkable broadening from the pure Debye relaxation is identified for the slowest dynamics, differing from the dielectric spectra of short-chain alcohols. The broadening of the Debye-like relaxation in the two liquids develops as temperature increases, and the approaching of the Debye-like and structural relaxation widths is shown. Similar results are observed in the dielectric spectra of dilute 2-ethyl-1-hexanol in either 2-hexyl-1-decanol or squalane. The results of the liquids and mixtures reveal a correlation between the broadening and the Debye-like relaxation strength. Molecular associations in monohydroxy alcohols are discussed with the modification of the Debye relaxation.
Finite-difference time-domain simulation of laser beam absorption in fully penetrated keyholes
Authors: Deng Chun , Ki Hyungson
Published: October 2013

Accurate predictions of laser beam absorptance and how laser beam energy is distributed on a keyhole surface are arguably the most important but challenging tasks in the study of laser keyhole welding. In this article, laser interaction with fully penetrated keyholes has been studied by solving the Maxwell equations for electrodynamics using the finite-difference time-domain method with the Drude model for metals. Based on the experimental observations of Fabbro et al. [J. Phys. D: Appl. Phys. 38, 1881–1887 (2005)], the keyhole is simplified as a tilted cylinder, and we have extensively investigated laser absorption phenomena considering three materials (Fe, Sn, and Al), three beam polarizations (two linear and circular), two laser beam wavelengths (1.06 μm and 10.6 μm), and six keyhole tilting angles (0°, 10°, 20°, 30°, 40°, and 45°). To the best of the authors' knowledge, this is the first electrodynamic simulation of a laser manufacturing process and reveals some interesting findings concerning laser beam absorption characteristics that can be only obtained by full electrodynamic simulations.
Megawatt-power Ka-band gyroklystron oscillator with external feedback
Authors: Guznov Y. M. , Danilov Y. Y. , Kuzikov S. V. , Novozhilova Y. V. , Shevchenko A. S. , Zaitsev N. I. , Ryskin N. M.
Published: October 2013

We report design and experimental demonstration of a high-power regenerative oscillator based on the gyroklystron amplifier with external delayed feedback. The oscillator operates on axially non-symmetric TE7.1.1 and TE7.3.1 modes in the input and output cavity, respectively. Peak output power of 1.5–2.0 MW with nearly 1 μs pulse duration in Ka-band is observed experimentally. Application of the selective delayed feedback not only overcomes the mode competition problem but also provides controlled mode switching within 1–2 GHz frequency band.
Dielectric properties of highly anisotropic nematic liquid crystals for tunable microwave components
Authors: Kowerdziej R. , Parka J. , Krupka J. , Olifierczuk M. , Nowinowski-Kruszelnicki E. , Jaroszewicz L. , Chojnowska O.
Published: October 2013

In this Letter, we report on measurements of the complex permittivity of highly anisotropic nematic liquid crystals at microwave frequencies as a function of the AC bias voltage. Permittivity measurements have been performed by the split post dielectric resonator technique. The experiments have shown that when the AC bias voltage increases from 0 to 8 V, the real part of the permittivity of these liquid crystals changes by up to 28%. The tunability and the relatively low dielectric losses observed in these liquid crystal mixtures mean that they are ideal materials for the design of tunable microwave components.