bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of one dimension shock initiation of condensed explosive by SPH method
Authors: Yang Gang , Liu Rangqi , Hu De'an , Han Xu
Published: April 2016

Purpose

This paper aims to study the ability of SPH method in simulating shock initiation process. The initiation and subsequent explosion processes of condensed explosive involve high pressure propagation and material large deformation, which increase the simulation difficulty in using traditional mesh-based method. The study aims to take the SPH method as an alternative method to shock initiation simulation.

Design/methodology/approach

The SPH method combined with some correct aspects is applied to simulate the shock initiation process. The condensed explosive is ignited by the impact of high speed flyer. In order to avoid the non-physical penetration between particles of high velocity flyer and condensed explosive, a particle-to-particle contact algorithm is employed. After the ignition, the detonation process of condensed explosive is represented by the ignition and growth model. A modified SPH method based on Riemann-solver is applied to smooth the numerical oscillation at shock front. Two numerical examples are implemented to illustrate the capability of SPH method in shock initiation simulation. One is the interface velocity experiment of PBX-9501. Another is the plate push experiment of PBX-9502. Both of the examples include the shock initiation process of condensed explosive.

Findings

Numerical results show that the shock initiation process of condensed explosive can be well predicted by SPH method. The characteristics of detonation are captured in the simulation. The measured data in numerical examples are also in good agreement with the experimental data.

Research limitations/implications

Because of the research purpose is to study the ability of SPH for shock initiation simulation, only one-dimension numerical examples are discussed in the paper. Therefore, researchers are encouraged to extend and test the proposed method to two or three dimension shock initiation problems simulation.

Originality/value

This paper provides an alternative method for shock initiation simulation. The implemented method can overcome the weaknesses of traditional mesh based method in simulation of shock initiation problems.
Approximation based curvilinear local search for optimization problems
Authors: Yaman Fatih , Yilmaz Asim Egemen , Leblebicioğlu Kemal
Published: April 2016

Purpose

At this work, we propose a local approximation based search method to optimize any function. For this purpose, an approximation method is combined with an estimation filter, and a new local search mechanism is constituted.

Design/methodology/approach

RBF network is very efficient interpolation method especially if we have sufficient reference data. Here, reference data refers to the exact value of the objective function at some points. Using this capability of RBFs, we can approximately inspect the vicinity each point in search space. Meanwhile, in order to obtain a smooth, rapid and better trajectory toward the global optimum, the alpha-beta filter can be integrated to this mechanism. For better description and visualization, the operations are defined in 2-dimensional search space; but the outlined procedure can be extended to higher dimensions without loss of generality.

Findings

When compared with our previous studies using conventional heuristic methods, approximation based curvilinear local search mechanism provide better minimization performance for almost all benchmark functions. Moreover computational cost of this method too less than heuristics. The number of iteration down to at least 1/10 compared to conventional heuristic algorithm. Additionally, the solution accuracy is very improved for majority of the test cases.

Originality/value

This paper proposes a new search approach to solve optimization problems with less cost. For this purpose, a new local curvilinear search mechanism is built using RBF based approximation technique and alpha-beta estimation filter.
On the iterative methods for weighted linear least squares problem
Authors: Saberi Hashem , Edalatpanah SA
Published: April 2016

Purpose

The Weighted Linear Least Squares (WLLS) problem has many different applications in sciences and engineering. The purpose of this paper is to introduce an iterative scheme for solving the WLLS problem.

Design/methodology/approach

By considering the splitting techniques in conjunction with Generalized Accelerated Over-relaxation (GAOR) method the authors design a new iterative method to solve the weighted linear least squares problem. Furthermore, within the computational framework, some models of iterative schemes candidates are investigated and evaluated.

Findings

In this paper, the authors propose an efficient iterative scheme for solving the WLLS problem. The proposed scheme presented promising results from the aspects of both convergence behavior and performance. Moreover, comparative results for the proposed schemes are also presented.

Research limitations/implications

Comparison between the new methods and other similar methods for the studied problem shows a remarkable agreement and reveals that the new model is much better in comparison with the existing methods in point of view rate of convergence and computing efficiency, as illustrated by the theoretical analysis and numerical results presented.

Originality/value

For solving WLLS more attention has recently been paid on a special class of splitting techniques with the preconditioned GAOR method. In this paper, the authors use a different splitting for the GAOR method and present a promising class of methods. The convergence results of the iterative algorithm are also proposed. Several examples are given to show the efficiency of the presented methods.
Hybrid vibration and rest-to-rest control of a two-link flexible robotic arm using H∞ loop-shaping control design
Authors: sayahkarajy Mostafa , Mohamed Z , Faudzi A.A.M. , Supriyanto E.
Published: April 2016

Purpose

This study presents a method for simultaneous motion and vibration control of light-weight slender robotic arms, known as flexible manipulators. In this paper, a new control algorithm is proposed for a two-link manipulator with elastic links.

Design/methodology/approach

The controller includes a MIMO H∞ Loop-Shaping Design (H∞LSD) as the feedback controller, and a command pre-shaping filter as the feed-forward controller. The conventional inputs and outputs of a typical two-link manipulator , that consists of the torques applied by the actuators at the joints, and the joint angles are chosen for the feedback control.

Findings

It is shown that by selecting a proper desired loop shape, the H∞LSD is able to control the joint angles of the manipulator, and simultaneously, suppress vibrations of the system so that the high frequency chatter due to the structural vibration modes does not appear at the outputs. Then it is shown that when the H∞LSD is equipped with a command pre-shaping filter, more efficient suppression of the chatter at the tip of the manipulator is achieved. The capability and effectiveness of the proposed control strategy in driving and stabilizing the manipulator to desired positions and simultaneously suppressing structural vibrations is shown by the simulation of the flexible manipulator in rest-to-rest maneuvers.

Practical implications

Flexible Manipulator, Space Manipulators

Originality/value

A robust MIMO controller is proposed for simultaneous motion and vibration control of flexible manipulator.
Numerical investigation of clocking effect on a centrifugal pump with inlet guide vanes
Authors: QU WANSHI , tan lei , CAO Shuliang , WANG YUCHUAN , XU YUN
Published: April 2016

Purpose

The paper aims to investigate the clocking effect on a centrifugal pump with inlet guide vanes (IGVs).

Design/methodology/approach

The paper uses a computation fluid dynamics (CFD) framework to solve the unsteady flows in a centrifugal pump with inlet guide vanes. The relative position between the stationary vanes and the stationary volute tongue is defined as the clocking position when IGVs inside the suction pipe rotate along the circumferential direction.

Findings

The results show that clocking positions have little effect on the pump head and efficiency, however their influences are obvious for the pressure fluctuation and flow field in the centrifugal pump. The maximum difference of pressure amplitude at dominant frequency reach up to 28% on the monitoring point V8 at different clocking positions under design flow rate. For the large flow rate, the clocking effect on flow field and pressure fluctuation in centrifugal pump is similar to that of design flow rate. However, the clocking effect is nearly negligible at partial flow rate, because there are reverse flows around the tongue tip and obvious vortexes forming and developing in the impeller. Those complex phenomena interacting in the centrifugal pump make the clocking effect less evident.

Originality/value

The numerical investigation reveals the clocking effect on a centrifugal pump with inlet guide vanes, which also valuable for the stable operation and optimal design of centrifugal pumps.
Capital factors and rural women entrepreneurship development
Authors: Kungwansupaphan Chonnatcha , Leihaothabam Jibon Kumar Sharma
Published: April 2016

Purpose

The purpose of this paper is to investigate the roles of four specific capital factors, namely, human, social, institutional and financial capitals, in rural women entrepreneurship. The focus was on the handloom sector in Manipur, India.

Design/methodology/approach

This paper uses qualitative research methodology with a multiple case study approach. Data were collected using in-depth interviews to study seven cases of rural women entrepreneurs.

Findings

The study highlights that human, social, institutional and financial capitals play significant roles in encouraging rural women to engage in entrepreneurial activities and influence strategic decisions. Each capital factor being interrelated, achieving the integration among them will considerably enhance entrepreneurial success.

Research limitations/implications

The main limitation is the narrow scope, emphasizing on only four capital factors. There are implications for further work on other types of capital. The study being sector specific, limits generalization. It contributes insights into the need for multi-sector examinations in the literature.

Practical implications

Rural women entrepreneurship needs are in line with understanding the roles of capital factors and their interrelations. The role of capital factors varies between prior and no prior entrepreneurial experiences.

Originality/value

This study provides information on the role of capital factors on rural women entrepreneurship and contributes to better understanding of how each capital factor is accumulated and utilized in rural women entrepreneurship development using the perspective of handloom sector in Manipur, India.
Revisiting Okun’s Law in European Union countries
Authors: Economou Athina , Psarianos Iacovos N.
Published: April 2016

Purpose

– The purpose of this paper is to examine Okun’s Law in European countries by distinguishing between the transitory and the permanent effects of output changes upon unemployment and by examining the effect of labor market protection policies upon Okun’s coefficients.

Design/methodology/approach

– Quarterly data for 13 European Union countries, from the second quarter of 1993 until the first quarter of 2014, are used. Panel data techniques and Mundlak decomposition models are estimated.

Findings

– Okun’s Law is robust to alternative specifications. The effect of output changes to unemployment rates is weaker for countries with increased labor market protection expenditures and it is more persistent for countries with low labor market protection.

Originality/value

– The paper provides evidence that the permanent effect of output changes upon unemployment rates is quantitatively larger than the transitory impact. In addition, it provides evidence that increased labor market protection mitigates the adverse effects of a decrease in output growth rate upon unemployment.
How does the minimum wage affect employment statuses of youths?: evidence of Indonesia
Authors: Pratomo Devanto Shasta
Published: April 2016

Purpose

– The purpose of this paper is to examine the effects of minimum wage on youth employment across employment statuses in Indonesia. This study uses the National Labour Force Survey (Sakernas) from 2010 to 2012.

Design/methodology/approach

– This study uses a multinomial logit model to see the youth distribution across different employment status changes as a result of an increase in the minimum wage. Five categories of youth employment statuses are examined including self-employed; unpaid family workers; paid employees in the covered sector; paid employees in the uncovered sectors; and unemployed. The model is examined separately for urban and rural areas, as well as for the male and female youth labour market.

Findings

– The results generally suggest that an increase in minimum wage decrease the probability of youth being employed in the covered sector, i.e. paid employment in the covered sector and increase the probability of youth being employed in the uncovered sectors, including self-employed, unpaid family workers, and paid employment in the uncovered sectors. This study indicates a displacement effect for youths from the covered sector into the uncovered sector as suggested by the two-sector model. The specific results are different across urban and rural labour markets, as well as across males and females.

Originality/value

– Compared to the developed country studies, the studies on the effects of minimum wage on youth employment in developing countries is relatively limited. The sample from Indonesian labour market with a large informal sector has never been used for these purposes. This study also contributes to the literature by using the particular definition of the covered-uncovered sector to the Indonesian labour market based on the employment status and individual wage data.
Place-based brand experience, place attachment and loyalty
Authors: Cardinale Sylvia , Nguyen Bang , Melewar TC
Published: April 2016

Purpose

This research explores (1) whether the experience of a winery visit may lead to a customer’s emotional attachment to the place where the winery is located and (2) whether this can lead to the establishment of long lasting relationships and loyalty to the place. The context of the study is the wine region of Friuli Colli Orientali in the North East of Italy.

Design/methodology/approach

Using a mixed-method approach, data from across the zone of Friuli Colli Orientali were obtained through a combination of interviews and a questionnaire survey. With responses from 10 wine buyers in a series of interviews and 210 usable questionnaires, the authors test the study’s hypotheses to investigate the behaviors of wine clients.

Findings

Findings show that a positive winery experience – consisting of relaxing, educational, entertaining, aesthetical and well-served tasting of good products - in a winery, develop both emotional attachment and subsequent loyalty to the place in which the winery is located.

Practical implications

For marketers, it is necessary to have a positive overall experience with a place-based brand. Providing customers with the above positive experiences make them feel attached to the place in which the winery is located and make them desire to return and become loyal visitors of the area. The wineries, providing positive experiences, should make all customers feel at home, attached and should encourage them to visit the zone again. Repeated visits will increase place attachment and subsequently, place loyalty. It is also necessary to gain new customers. The study shows that if the current clients are satisfied, they will spread positive WOM, encouraging other travellers to visit the place-based brand.

Originality/value

Several contributions have been made to the literatures. First, the study identified place-based brand experience (PBBE) dimensions in a winery visit. Second, the study provided information to clarify the relationships between place-based brand experience, brand attachment and brand loyalty in a framework. Finally, the study demonstrated that place-based brand experience lead to place attachment and place loyalty in a new context.
Eco‐evolutionary dynamics in plant–soil feedbacks
Authors: terHorst Casey P. , Zee Peter C.
Published: April 2016

In the past decade, ecologists have begun to more fully appreciate the role of evolution in explaining contemporary ecological processes. Evolution is most likely to affect ecological patterns when selection pressure is particularly strong, or when the generation time of at least one interacting species is relatively short.

Interactions between plants and soil microbes are an excellent candidate for examining eco–evo interactions because interactions between organisms are tightly knit with the potential for species with relatively short generation times to impose strong selection on one another. Here, we examine the potential for eco–evolutionary dynamics in plant–soil feedbacks (PSFs).

Genetic variation in plant traits and subsequent evolution of those traits can affect traits and species composition of soil microbial communities. Soil microbial communities can, in turn, alter the evolutionary trajectory of plant traits. Further, the direction and magnitude of PSFs can affect the plant community, which may alter the selection on plant traits via intra‐ and interspecific interactions.

Finally, we consider how eco‐evolutionary feedbacks might enhance or mitigate the effects of PSFs in driving the structure of natural plant communities.
Climate adaption and post‐fire restoration of a foundational perennial in cold desert: insights from intraspecific variation in response to weather
Authors: Brabec Martha M. , Germino Matthew J. , Richardson Bryce A.
Published: April 2016

The loss of foundational but fire‐intolerant perennials such as sagebrush due to increases in fire size and frequency in semi‐arid regions has motivated efforts to restore them, often with mixed or even no success. Seeds of sagebrush Artemisia tridentata and related species must be moved considerable distances from seed source to planting sites, but such transfers have not been guided by an understanding of local climate adaptation. Initial seedling establishment and its response to weather are a key demographic bottleneck that likely varies among subspecies and populations of sagebrush.

We assessed differences in survival, growth and physiological responses of sagebrush seedlings to weather among eleven seed sources that varied in subspecies, cytotype and climates‐of‐origin over 18 months following outplanting. Diploid or polyploid populations of mountain, Wyoming and basin big sagebrush (A. tridentata ssp. vaseyana, A. tridentata ssp. wyomingensis and A. tridentata ssp. tridentata, respectively) were planted onto five burned sites that normally support A.t. wyomingensis with some A.t. tridentata.

A.t. wyomingensis had the most growth and survival, and tetraploid populations had greater survival and height than diploids. Seasonal timing of mortality varied among the subspecies/cytotypes and was more closely related to minimum temperatures than water deficit.

Temperatures required to induce ice formation were up to 6 °C more negative in 4n‐A.t. tridentata and A.t. wyomingensis than in other subspecies/cytotypes, indicating greater freezing avoidance. In contrast, freezing resistance of photosynthesis varied only 1 °C among subspecies/cytotypes, being greatest in A.t. wyomingensis and least in the subspecies normally considered most cold‐adapted, A.t. vaseyana. A large spectrum of reliance on freezing avoidance vs. freezing tolerance was observed and corresponded to differences in post‐fire survivorship among subspecies/cytotypes. Differences in water deficit responses among subspecies/cytotypes were not as strong and did not relate to survival patterns.

Synthesis and applications. Low‐temperature responses are a key axis defining climate adaptation in young sagebrush seedlings and vary more with cytotype than with subspecies, which contrasts with the traditional emphases on (i) water limitations to explain establishment in these deserts, and (ii) subspecies in selecting restoration seedings. These important and novel insights on climate adaptation are critical for seed selection and parameterizing seed transfer zones, and were made possible by incorporating weather data with survival statistics. The survival/weather statistics used here could be applied to any restoration planting or seeding to help elucidate factors contributing to success and enable adaptive management.
Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops
Authors: Hackett Sean C. , Bonsall Michael B.
Published: April 2016

The evolution of resistance to pesticides by insect pests is a significant challenge for sustainable agriculture. For transgenic crops expressingBacillus thuringiensis(Bt), crystalline (Cry) toxins resistance evolution may be delayed by the high‐dose/refuge strategy in which a non‐toxic refuge is planted to promote the survival of susceptible insects. The high‐dose/refuge strategy may interact with fitness costs associated with resistance alleles to further delay resistance. However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. Furthermore, the potential dynamic consequences of restricting susceptible insects to a refuge which represents only a fraction of the available space have rarely been considered.

We present a generalized discrete time model which utilizes dynamic programming methods to derive the optimal management decisions for the control of a theoretical insect pest population exposed to Bt crops. We consider three genotypes (susceptible homozygotes, resistant homozygotes and heterozygotes) and implement fitness costs of resistance to Bt toxins as either a decrease in the relative competitive ability of resistant insects or as a penalty on fecundity. Model analysis is repeated and contrasted for two types of density dependence: uniform density dependence which operates equally across the landscape and heterogeneous density dependence where the intensity of competition scales inversely with patch size and is determined separately for the refuge and Bt crop.

When the planting of Bt is decided optimally, fitness costs to fecundity allow for the planting of larger areas of Bt crops than equivalent fitness costs that reduce the competitive ability of resistant insects.

Heterogeneous competition only influenced model predictions when the proportional area of Bt planted in each season was decided optimally and resistance was not recessive.

Synthesis and applications. The high‐dose/refuge strategy alone is insufficient to preserve susceptibility to transgenicBacillus thuringiensis(Bt) crops in the long term when constraints upon the evolution of resistance are not insurmountable. Fitness costs may enhance the delaying effect of the refuge, but the extent to which they do so depends upon how the cost is realized biologically. Fitness costs which apply independently of other variables may be more beneficial to resistance management than costs which are only visible to selection under a limited range of ecological conditions.
Matrix‐Matching as an Improvement Strategy for the Detection of Pesticide Residues
Authors: Giacinti Géraldine , Raynaud Christine , Capblancq Sophie , Simon Valérie
Published: April 2016

More than 90% of the pesticides residues in apples are located in the peel. We developed a gas chromatography/ion trap tandem mass spectrometry method for investigating all detectable residues in the peel of 3 apple varieties. Sample preparation is based on the use of the Quick Easy Cheap Effective Rugged and Safe method on the whole fruit, the flesh, and the peel. Pesticide residues were quantified with solvent‐matched and matrix‐matched standards, by spiking apple sample extracts. Matrix effects dependent on the type of extract (fruit, flesh, or peel) and the apple variety were detected. The best data processing methods involved normalizing matrix effect rates by matrix‐matched internal/external calibration. Boscalid, captan, chlorpyrifos, fludioxonil, and pyraclostrobin were the most frequently detected pesticides. However, their concentrations in the whole fruit were below European maximum residue levels. Despite negative matrix effects, the residues in peel were detected at concentrations up to 10 times higher than those in whole fruits. Consequently, other pesticide residues present at concentrations below the limit of quantification in the whole fruit were detected in the peel.
Firms with Inconsistently Signed Earnings Surprises: Do Potential Investors Use a Counting Heuristic?
Authors: Koonce Lisa , Lipe Marlys Gascho
Published: April 2016

Although prior research reports that firms that consistently beat their earnings expectations are rewarded with a market‐valuation premium, most firms are inconsistent in the sign of their benchmark performance, sometimes missing and sometimes beating. In this paper, we report the results of multiple experiments to test the idea that potential investors, evaluating firms that have inconsistent benchmark performance, use a counting heuristic to discriminate among them. Our results provide strong support for the hypothesis that these investors distinguish among firms by counting the number of beats and misses they experience over an observed time interval. The judgmental effect of this beat‐frequency is incremental to the effect of the magnitude of the beats and misses of the benchmark. Our study has implications for firm managers who have inconsistent benchmark performance, suggesting that market participants do make systematic discriminations among such inconsistent firms. It also has implications for researchers by introducing a new theoretical construct to the literature—namely, the counting heuristic.
Risk factor analysis of parenteral nutrition‐associated cholestasis in extremely low birth weight infants
Authors: Lee Hyon Hui , Jung Ji Mi , Nam So‐Hyun , Lim Gina , Chung Mi Lim
Published: April 2016

Aim

Parenteral nutrition (PN) provides an alternative nutrition source for preterm infants who are intolerant of enteral nutrition. However, prolonged PN increases the risk of PN‐associated cholestasis (PNAC). We conducted this study to determine the incidence and risk factors of PNAC in extremely low birth weight (ELBW) infants.

Methods

We retrospectively reviewed the medical records of ELBW infants from March 2010 to April 2015. PNAC was diagnosed in infants with a history of PN for at least two weeks and direct bilirubin concentrations >2 mg/dL after other causes of neonatal cholestasis were excluded.

Results

Of the 114 eligible ELBW infants, 41 (36%) were diagnosed with PNAC. The multivariate analysis showed that birth weight, sepsis, necrotising enterocolitis, fluconazole prophylaxis and the duration of PN and hospitalisation were independent risk factors for the development of PNAC (p < 0.05). However, parenteral fish oil‐based lipid preparation (FOLP) did not reduce the risk of PNAC. Although PNAC was not a direct cause of death, it was associated with an increased risk of mortality.

Conclusion

PNAC was common in ELBW infants, was associated with various clinical factors and increased the risk of mortality. However, we did not observe the protective effect of FOLP against PNAC.
Diaoyu Dao, Diaoyutai or Senkaku? Creative solutions to a festering dispute in the East China Sea from an ‘Island Studies’ perspective
Authors: Baldacchino Godfrey
Published: April 2016

This paper draws on extensive island examples with a view to offer ‘creative’ solutions to the ongoing dispute over the Diaoyu/Diaoyutai/ Senkaku Islands between China (and Taiwan) and Japan in the East China Sea. In spite of the rhetoric and apparent intractability of island conflicts, there are various examples from the past (and the present) that suggest how island disputes may be decided, and in ‘win–win’ ways, to the satisfaction of the different parties involved. The resolution of island territorial problems can benefit greatly from a critical appreciation of how other small islands, also contested, have had their situation resolved in non‐zero‐sum ways. In such cases, sovereignty has been shared, split/divided or expunged; in other cases, sovereignty disputes have been put aside in order to co‐develop and co‐exploit natural resources. There is also one example of a UNESCO World Heritage Site consisting of a string of small islands and surrounding waters whose management is shared between three countries.
Multifunctionality and agrarian transition in alternative agro‐food production in the global South: The case of organic shrimp certification in the Mekong Delta, Vietnam
Authors: Omoto Reiko , Scott Steffanie
Published: April 2016

Processes of globalisation in the conventional food provision system have had widespread negative impacts on small‐scale farmers. Yet, alternative food networks, which are characterised by more sustainable production/consumption practices and fairer trade relations, have increasingly been ‘going global’ and, in the process, have been integrating small‐scale farms in the South. One such high‐value export‐led commodity is certified organic shrimp. International third‐party certification schemes are becoming popular as a tool to verify the intangible attributes of such commodities. Using concepts of multifunctionality and agrarian change, this paper examines the implications of introducing an international environmental certification programme to a site where the ‘peasantry’ has been preserved and has limited integration in the global agro‐food system. Drawing on a case study that examines the first certified organic shrimp production project in Vietnam, this paper concludes that the current movement towards post‐productivism in the global North has potential to keep local farming practices in the global South by justifying the value of peasant‐like production methods through international certification. As a result, the development path of agrarian transition might be reshaped into a form not necessarily pursuing industrialisation. This leads to the new interpretation of pre‐ and post‐productivism beyond the North and South divide.
Last days in the Carteret Islands? Climate change, livelihoods and migration on coral atolls
Authors: Connell John
Published: April 2016

It is widely assumed that the impacts of climate change on atolls will render them uninhabitable. The Carteret Islands, an iconic Pacific atoll, is experiencing physical changes, documented in the media, the outcome of multiple factors, alongside critical economic livelihood problems. Its population has sought to resettle on nearby Bougainville Island, but land has not become available. The search for migration opportunities parallels trends on coral atolls elsewhere where survival strategies have involved regional and international ties, with cultures of migration, focused on more distant international destinations. Carteret Islanders have not been able to mobilise similar relationships. For many atolls and atoll states, migration has increasingly become a livelihood strategy, irrespective of climate change. That is likely to become even more true in the future, but the outcome will be dependent on policies and practices in metropolitan destination states.
Pharmacokinetics of lamotrigine and its metabolite N‐2‐glucuronide: Influence of polymorphism of UDP‐glucuronosyltransferases and drug transporters
Authors: Milosheska Daniela , Lorber Bogdan , Vovk Tomaž , Kastelic Matej , Dolžan Vita , Grabnar Iztok
Published: April 2016

Aims

This study aimed to develop a population pharmacokinetic model for quantitative evaluation of the influence of genetic variants in metabolic enzymes and transporters on lamotrigine pharmacokinetics while taking into account the influence of various clinical, biochemical and demographic factors.

Methods

We included 100 patients with epilepsy on stable dosing with lamotrigine as mono or adjunctive therapy. Lamotrigine and lamotrigine N‐2‐glucuronide concentrations were determined in up to two plasma samples per patient. Patients were genotyped for UGT1A4, UGT2B7, ABCB1 and SLC22A1. Population pharmacokinetic analysis was performed by non‐linear mixed effects modelling. Prior knowledge from previous pharmacokinetic studies was incorporated to stabilize the modelling process. A parent–metabolite model was developed to get a more detailed view on the covariate effects on lamotrigine metabolism.

Results

With a base model absorption rate (interindividual variability) was estimated at 1.96 h−1 (72.8%), oral clearance at 2.32 l h−1 (41.4%) and distribution volume at 77.6 l (30.2%). Lamotrigine clearance was associated with genetic factors, patient's weight, renal function, smoking and co‐treatment with enzyme inducing or inhibiting drugs. In patients with UGT2B7–161TT genotype clearance was lower compared with GT and GG genotypes. Clearance was particularly high in patients with UGT2B7 372 GG genotype (compared with AA genotype it was 117%; 95% CI 44.8, 247% higher).

Conclusions

Variability in lamotrigine pharmacokinetics is large and quantification of its sources may lead to more precise individual treatment. Genotyping for UGT2B7 may be useful in various clinical settings.
miR‐199a‐5p regulates β1 integrin through Ets‐1 to suppress invasion in breast cancer
Authors: Li Wentong , Wang Hui , Zhang Jinbao , Zhai Limin , Chen Weijuan , Zhao Chunling
Published: April 2016

Increasing evidence has revealed that miR‐199a‐5p is actively involved in tumor invasion and metastasis as well as in the decline of breast cancer tissues. In this research, overexpression of miR‐199a‐5p weakened motility and invasion of breast cancer cells MCF‐7 and MDA‐MB‐231. Upregulation of Ets‐1 increased breast cancer cell invasion, but the mechanism by which miR‐199a‐5p modulates activation of Ets‐1 in breast cancer was not clarified. We investigated the relationship between miR‐199a‐5p and Ets‐1 on the basis of 158 primary breast cancer case specimens, and the results showed that Ets‐1 expression was inversely correlated with endogenous miR‐199a‐5p. Overexpression of miR‐199a‐5p reduced the mRNA and protein levels of Ets‐1 in MCF‐7 and MDA‐MB‐231 cells, whereas anti‐miR‐199a‐5p elevated Ets‐1. siRNA‐mediated Ets‐1 knockdown phenocopied the inhibition invasion of miR‐199a‐5p in vitro. Moreover, luciferase reporter assay revealed that miR‐199a‐5p directly targeted 3′‐UTR of Ets‐1 mRNA. This research revealed that miR‐199a‐5p could descend the levels of β1 integrin by targeting 3′‐UTR of Ets‐1 to alleviate the invasion of breast cancer via FAK/Src/Akt/mTOR signaling pathway. Our results provide insight into the regulation of β1 integrin through miR‐199a‐5p‐mediated Ets‐1 silence and will help in designing new therapeutic strategies to inhibit signal pathways induced by miR‐199a‐5p in breast cancer invasion.
Phylogenomics and historical biogeography of the monocot order Liliales: out of Australia and through Antarctica
Authors: Givnish Thomas J. , Zuluaga Alejandro , Marques Isabel , Lam Vivienne K. Y. , Gomez Marybel Soto , Iles William J. D. , Ames Mercedes , Spalink Daniel , Moeller Jackson R. , Briggs Barbara G. , Lyon Stephanie P. , Stevenson Dennis W. , Zomlefer Wendy , Graham Sean W.
Published: April 2016

We present the first phylogenomic analysis of relationships among all ten families of Liliales, based on 75 plastid genes from 35 species in 29 genera, and 97 additional plastomes stratified across angiosperm lineages. We used a supermatrix approach to extend our analysis to 58 of 64 genera of Liliales, and calibrated the resulting phylogeny against 17 fossil dates to produce a new timeline for monocot evolution. Liliales diverged from other monocots 124 Mya and began splitting into separate families 113 Mya. Our data support an Australian origin for Liliales, with close relationships between three pairs of lineages (Corsiaceae/Campynemataceae, Philesiaceae/Ripogonaceae, tribes Alstroemerieae/Luzuriageae) in South America and Australia or New Zealand reflecting teleconnections of these areas via Antarctica. Long‐distance dispersal (LDD) across the Pacific and Tasman Sea led to re‐invasion of New Zealand by two lineages (Luzuriaga, Ripogonum); LDD allowed Campynemanthe to colonize New Caledonia after its submergence until 37 Mya. LDD permitted Colchicaceae to invade East Asia and Africa from Australia, and re‐invade Africa from Australia. Periodic desert greening permitted Gloriosa and Iphigenia to colonize Southeast Asia overland from Africa, and Androcymbium–Colchicum to invade the Mediterranean from South Africa. Melanthiaceae and Liliaceae crossed the Bering land‐bridge several times from the Miocene to the Pleistocene.
Colorectal anastomotic leakage corrected by transanal laparoscopy
Authors: Dapri G. , Guta D. , Grozdev K. , Antolino L. , Bachir N. , Jottard K. , Cadière G.‐B.
Published: April 2016

Aim

Interest in transanal laparoscopy has increased in the last decade. This approach can allow primary procedures such as polypectomy, total mesorectal excision and the treatment of postoperative complications such as bleeding, leakage and fistula formation.

Method

Two patients treated by transanal repair for leakage of a colorectal anastomosis after laparoscopic anterior resection of the rectum are reported. The first developed leakage immediately during the surgery and in the second leakage presented at 4 weeks. A new transanal platform according to DAPRI (Karl Storz‐Endoskope, Tuttlingen, Germany), formed by a reusable port and reusable monocurved instruments was developed to permit manipulation of sutures introduced via the anus in a maximally ergonomic manner. Laparoscopic suturing was performed transanally and a protective ileostomy was added as well.

Results

The transanal procedures took 60 and 45 min and the patients were discharged after 5 days and 2 days. At 2 months both defects were found to be healed on contrast radiology and endoscopy; therefore the ileostomy was closed. Anal function was satisfactory with a frequency of two and one times per 24 h with no incontinence or evidence of sepsis.

Conclusion

Intra‐operative or late leakage of colorectal anastomosis can be safely treated by transanal laparoscopy. This new transanal platform offers the surgeon the possibility to work in ergonomic positions, without increasing the cost of the procedure thanks to the reusable nature of the material used.
THE IMPACT OF TAX PRICE CHANGES ON CHARITABLE CONTRIBUTIONS TO THE NEEDY
Authors: Zampelli Ernest M. , Yen Steven T.
Published: April 2016

Eliminating or reducing the federal charitable deduction can have serious impacts on the level of charitable donations. Tax price elasticity estimates from a multivariate sample selection model indicate that changing the deduction to a 12% tax credit would have reduced individual donations in 2012 by 18.9% if applied to itemizing taxpayers and by 10.5% if extended to nonitemizers. Elimination of the deduction would have led to a 35% reduction in individual charitable donations. Even if coupled with cuts in marginal tax rates, eliminating the charitable deduction will still likely result in substantial reductions given the inelastic income elasticities of charitable donations. The estimates justify the ardent opposition of many in the nonprofit sector to the more radical proposals for changing the tax treatment of charitable contributions. (JEL D34, C34)
Zinc oxide nanoparticles inhibit expression of manganese superoxide dismutase via amplification of oxidative stress, in murine photoreceptor cells
Authors: Guo Da Dong , Li Qin , Tang Hong Ying , Su Jing , Bi Hong Sheng
Published: April 2016

Objectives

As a parenchymal cell, the photoreceptor is more susceptible to alterations in outer micro‐environmental conditions than other cells. In the present study, we aimed to investigate inhibitory effects of zinc oxide (ZnO) nanoparticles on expression of manganese superoxide dismutase (MnSOD) in murine photoreceptor‐derived cells.

Materials and methods

We investigated effects of ZnO nanoparticles on murine photoreceptor cell viability and on expression and activity of MnSOD using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay, immunofluorescence analysis, flow cytometry, quantitative real‐time PCR and enzyme‐linked immunosorbent assay (ELISA).

Results

ZnO nanoparticles were found to have higher cytotoxic effects in concentration‐ and time‐dependent manners, to elevate intracellular levels of hydrogen peroxide and hydroxyl radicals, and thus to induce overproduction of reactive oxygen species (ROS) and collapse of mitochondrial membrane potential, leading to cell damage. Moreover, ZnO nanoparticles also significantly reduced expression of MnSOD at both the mRNA and protein levels, reduced its activity, and further aggravated oxidative stress‐mediated cell damage.

Conclusion

Overall, ZnO nanoparticle‐induced cytotoxicity was associated with elevated levels of oxidative stress due to overproduction of ROS and reduced expression and activity of MnSOD.
Use of Fluoroscopy–Echocardiography Fusion Imaging in Transcatheter Aortic Valve Replacement
Authors: Eskandari Mehdi , Dworakowski Rafal , Byrne Jonathan , Wendler Olaf , MacCarthy Philip , Monaghan Mark
Published: April 2016

Mini‐Abstract

Coregistration of real time two‐dimensional and three‐dimensional echocardiography with fluoroscopy providing “hybrid imaging” has recently become commercially available and has been used in a range of structural heart intervention. We present how such a technique can be integrated into the transcatheter aortic valve replacement procedure.
Foraging activity of leaf‐cutting ants changes light availability and plant assemblage in Atlantic forest
Authors: CORRÊA MICHELE M. , SILVA PAULO S. D. , WIRTH RAINER , TABARELLI MARCELO , LEAL INARA R.
Published: April 2016

1. Leaf‐cutting ants (LCAs) have often been denoted as ecosystem engineers because of their multifarious effects on the vegetation, particularly via nest‐driven environmental changes. However, the non‐trophic impacts of LCAs on forest dynamics via foliage harvesting across sizeable foraging zones (so‐called associated ecosystem engineering) are still poorly investigated.

2. Here, light availability and sapling assemblages were assessed within foraging areas and ant‐free control zones of 16 Atta cephalotes colonies located in a large remnant of Atlantic forest in northeastern Brazil.

3. Canopy openness and total light transmission were 1.4 and 1.6 times higher in foraging zones than in control areas. In parallel, sapling density and species richness decreased constantly from control to foraging zone plots. Additionally, shade‐tolerant species exhibited reduced abundance across foraging zones. A non‐metric multidimensional scaling ordination based on taxonomic similarity primarily segregated foraging zone and control plots; foraging zone plots converged to be more similar to each other as well. Finally, some plant species emerged as indicators of LCA‐free zones.

4. These results suggest that LCA foraging activity in the forest canopy directly increases the light availability and indirectly affects the recruitment and the structure of local plant assemblages.

5. Such a biologically significant effect on the light environment and its cascades confirms LCAs as potent ecosystem engineers, particularly as a plant assembly force, which operates beyond the spatial reach of their well‐described nest effects.
Differential effectiveness of selected non‐psychotropic phytocannabinoids on human sebocyte functions implicates their introduction in dry/seborrhoeic skin and acne treatment
Authors: Oláh Attila , Markovics Arnold , Szabó‐Papp Judit , Szabó Pálma Tímea , Stott Colin , Zouboulis Christos C. , Bíró Tamás
Published: April 2016

Acne is a common skin disease characterized by elevated sebum production and inflammation of the sebaceous glands. We have previously shown that a non‐psychotropic phytocannabinoid ((–)‐cannabidiol [CBD]) exerted complex anti‐acne effects by normalizing ‘pro‐acne agents’‐induced excessive sebaceous lipid production, reducing proliferation and alleviating inflammation in human SZ95 sebocytes. Therefore, in this study we aimed to explore the putative anti‐acne effects of further non‐psychotropic phytocannabinoids ((–)‐cannabichromene [CBC], (–)‐cannabidivarin [CBDV], (–)‐cannabigerol [CBG], (–)‐cannabigerovarin [CBGV] and (–)‐Δ9‐tetrahydrocannabivarin [THCV]). Viability and proliferation of human SZ95 sebocytes were investigated by MTT and CyQUANT assays; cell death and lipid synthesis were monitored by DilC1(5)‐SYTOX Green labelling and Nile Red staining, respectively. Inflammatory responses were investigated by monitoring expressions of selected cytokines upon lipopolysaccharide treatment (RT‐qPCR, ELISA). Up to 10 μm, the phytocannabinoids only negligibly altered the viability of the sebocytes, whereas high doses (≥50 μm) induced apoptosis. Interestingly, basal sebaceous lipid synthesis was differentially modulated by the substances: CBC and THCV suppressed it, and CBDV had only minor effects, whereas CBG and CBGV increased it. Importantly, CBC, CBDV and THCV significantly reduced arachidonic acid (AA)‐induced ‘acne‐like’ lipogenesis. Moreover, THCV suppressed proliferation, and all phytocannabinoids exerted remarkable anti‐inflammatory actions. Our data suggest that CBG and CBGV may have potential in the treatment of dry‐skin syndrome, whereas CBC, CBDV and especially THCV show promise to become highly efficient, novel anti‐acne agents. Moreover, based on their remarkable anti‐inflammatory actions, phytocannabinoids could be efficient, yet safe novel tools in the management of cutaneous inflammations.
A multi‐basin approach determines variability in host fish suitability for unionids in tributaries of the Laurentian Great Lakes
Authors: Caldwell Mandi L. , Zanatta David T. , Woolnough Daelyn A.
Published: April 2016

Freshwater mussel populations have declined, in part, from changes in host communities. However, it is unknown if fish from adjacent catchments could be used to augment mussel populations in the Great Lakes inland rivers, and if so, whether this association would be impacted by known genetic structure in mussels and fish.

This study tested how host fish origin (i.e. catchment) impacts the transformation of the endangered unionid Epioblasma triquetra from larval into juvenile life stages while concurrently considering potentially genetically distinct populations of mussels and hosts.

We quantitatively determined if Percina caprodes and Percina maculata from the Lake Michigan, Erie and Huron basins are laboratory‐successful hosts for E. triquetra. Experiments were performed in autumn and spring to document any seasonal effects on transformation.

Percina caprodes was reconfirmed to be a successful host for E. triquetra, and for the first time, P. maculata was also determined to be a successful host in the Great Lakes region. Results suggest no differences in juvenile transformation with allopatric and sympatric fish and mussel pairings based on Great Lakes basin origin; therefore, transformation success may not parallel differences in genetic structure. In addition, results suggest seasonal differences in the developmental stages of E. triquetra juveniles.

Knowing the most efficient strategy to optimise juvenile transformations can make reintroductions, augmentation and overall conservation efforts of E. triquetra successful. These data will help in developing recovery strategies for E. triquetra in the Laurentian Great Lakes by understanding variation in host use and nuances in this host–parasite relationship.