bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of the human DNA-repair protein RAD52 containing surface mutations
Authors: Saotome Mika , Saito Kengo , Onodera Keiichi , Kurumizaka Hitoshi , Kagawa Wataru
Published: July 2016

The Rad52 protein is a eukaryotic single-strand DNA-annealing protein that is involved in the homologous recombinational repair of DNA double-strand breaks. The isolated N-terminal half of the human RAD52 protein (RAD521–212) forms an undecameric ring structure with a surface that is mostly positively charged. In the present study, it was found that RAD521–212containing alanine mutations of the charged surface residues (Lys102, Lys133 and Glu202) is highly amenable to crystallization. The structure of the mutant RAD521–212was solved at 2.4 Å resolution. The structure revealed an association between the symmetry-related RAD521–212rings, in which a partially unfolded, C-terminal region of RAD52 extended into the DNA-binding groove of the neighbouring ring in the crystal. The alanine mutations probably reduced the surface entropy of the RAD521–212ring and stabilized the ring–ring association observed in the crystal.
Crystallization and X-ray diffraction analysis of anL-arabinonate dehydratase fromRhizobium leguminosarumbv.trifoliiand aD-xylonate dehydratase fromCaulobacter crescentus
Authors: Rahman Mohammad Mubinur , Andberg Martina , Koivula Anu , Rouvinen Juha , Hakulinen Nina
Published: July 2016

L-Arabinonate dehydratase (EC 4.2.1.25) and D-xylonate dehydratase (EC 4.2.1.82) are two enzymes that are involved in a nonphosphorylative oxidation pathway of pentose sugars. L-Arabinonate dehydratase converts L-arabinonate into 2-dehydro-3-deoxy-L-arabinonate, and D-xylonate dehydratase catalyzes the dehydration of D-xylonate to 2-dehydro-3-deoxy-D-xylonate. L-Arabinonate and D-xylonate dehydratases belong to the IlvD/EDD family, together with 6-phosphogluconate dehydratases and dihydroxyacid dehydratases. No crystal structure of any L-arabinonate or D-xylonate dehydratase is available in the PDB. In this study, recombinant L-arabinonate dehydratase fromRhizobium leguminosarumbv.trifolii(RlArDHT) and D-xylonate dehydratase fromCaulobacter crescentus(CcXyDHT) were heterologously expressed inEscherichia coliand purified by the use of affinity chromatography followed by gel-filtration chromatography. The purified proteins were crystallized using the hanging-drop vapour-diffusion method at 293 K. Crystals ofRlArDHT that diffracted to 2.40 Å resolution were obtained using sodium formate as a precipitating agent. They belonged to space groupP21, with unit-cell parametersa = 106.07,b= 208.61,c= 147.09 Å, β = 90.43°. EightRlArDHT molecules (two tetramers) in the asymmetric unit give aVMvalue of 3.2 Å3 Da−1and a solvent content of 62%. Crystals ofCcXyDHT that diffracted to 2.66 Å resolution were obtained using sodium formate and polyethylene glycol 3350. They belonged to space groupC2, with unit-cell parametersa= 270.42,b= 236.13,c = 65.17 Å, β = 97.38°. FourCcXyDHT molecules (a tetramer) in the asymmetric unit give aVMvalue of 4.0 Å3 Da−1and a solvent content of 69%.
Crystal structure of the fluorescent protein fromDendronephthyasp. in both green and photoconverted red forms
Authors: Pletneva Nadya V. , Pletnev Sergei , Pakhomov Alexey A. , Chertkova Rita V. , Martynov Vladimir I. , Muslinkina Liya , Dauter Zbigniew , Pletnev Vladimir Z.
Published: July 2016

The fluorescent protein fromDendronephthyasp. (DendFP) is a member of the Kaede-like group of photoconvertible fluorescent proteins with a His62-Tyr63-Gly64 chromophore-forming sequence. Upon irradiation with UV and blue light, the fluorescence of DendFP irreversibly changes from green (506 nm) to red (578 nm). The photoconversion is accompanied by cleavage of the peptide backbone at the Cα—N bond of His62 and the formation of a terminal carboxamide group at the preceding Leu61. The resulting double Cα=Cβbond in His62 extends the conjugation of the chromophore π system to include imidazole, providing the red fluorescence. Here, the three-dimensional structures of native green and photoconverted red forms of DendFP determined at 1.81 and 2.14 Å resolution, respectively, are reported. This is the first structure of photoconverted red DendFP to be reported to date. The structure-based mutagenesis of DendFP revealed an important role of positions 142 and 193: replacement of the original Ser142 and His193 caused a moderate red shift in the fluorescence and a considerable increase in the photoconversion rate. It was demonstrated that hydrogen bonding of the chromophore to the Gln116 and Ser105 cluster is crucial for variation of the photoconversion rate. The single replacement Gln116Asn disrupts the hydrogen bonding of Gln116 to the chromophore, resulting in a 30-fold decrease in the photoconversion rate, which was partially restored by a further Ser105Asn replacement.
Unlearning cynicism
Authors: Schraeder Mike , Jordan Mark H. , Self Dennis R. , Hoover David J.
Published: July 2016

Purpose

“Unlearning” is discussed as an additional perspective or supplemental strategy for managers/leaders to consider when addressing cynicism in organizations. The article is not intended to be definitive. The aim of this paper is to generate ideas and encourage further exploration amongst practitioners and scholars regarding the feasibility of this perspective. There are a number of plausible explanations for the origin of cynicism, including the notion that cynicism is learned. As anything that is learned can also be unlearned, “unlearning” seemed to be a compelling perspective worthy of further exploration.

Design/methodology/approach

A targeted literature review of cynicism (with a specific focus on some of the more salient and well-respected research) was utilized to develop a conceptual overview of cynicism, a discussion of key causes/antecedents of cynicism, and common symptoms of cynicism. Select literature was also reviewed relative to the concept of “unlearning”. These varied sources were then synthesized into a framework that outlined the premise of “unlearning” applied to cynicism in organizations.

Findings

This article focuses on the attitudinal dimension of cynicism, discussing “unlearning” as a possible method for addressing cynicism that can be used to supplement, but not necessarily replace, other methods that have proven effective.

Originality/value

Cynicism in organizations has received notable research attention. This article contributes to this important topic by exploring “unlearning” as a supplemental approach or perspective for addressing cynicism with the intent of generating ideas and encouraging further exploration of the feasibility of this approach.
Examining perceived organizational politics among Indian managers
Authors: Agarwal Upasna A.
Published: July 2016

Purpose

This paper aims to test the effects of perception of organizational politics (POPS) on work outcomes–work engagement, innovative work behaviour and turnover intention. Mediating role of work engagement and the moderating role oflocusof control (LOC) on perceived organizational politics–outcome (innovative work behaviour and turnover intention) relationship was investigated.

Design/methodology/approach

Data were gathered from a sample of 302 full-time managerial employees in India. Results suggest that perceived organizational politics is significantly related to intention to quit and innovative work behaviour, and this relationship is partially mediated by work engagement. LOC moderates the organizational politics–work outcomes (work engagement and innovative work behaviour) relationship.

Findings

The current research demonstrates that availability of a work environment, where there are unfair decisions, nepotism and favoritism, is an impediment to engagement, innovative work behaviour and retention of managers. It behooves of top management therefore focusing on reducing POPS and subsequent deficits in motivation by providing clear feedback regarding which behaviours their organization desires.

Research limitations/implications

The study focused on POPS as reported by the employees and not on actual political behaviours. As the study did not cover all sectors, the results of this study should be interpreted with caution.

Originality/value

The study extended the current research stream of perceived organizational politics research to one of the underrepresented developing Asian countries, India. The study also contributes in terms of its sample characteristics. Managerial employees working across different sectors, served as the setting of our empirical study.
Formation of strategic networks under high uncertainty of a megaproject
Authors: Jussila Anssi , Mainela Tuija , Nätti Satu
Published: July 2016

Purpose

The purpose of this paper is to examine the formation of strategic networks between second-tier actors in the context of a construction megaproject. The research question addressed is: How do second-tier strategic networks form in high uncertainty projects?

Design/methodology/approach

This is a qualitative single-case study, which examines strategic network formation in the context of a nuclear power plant construction project. Focused interviews with parties involved or having an interest in the megaproject were used as the primary data collection method.

Findings

The conditions for network formation in a megaproject context are specified with a focus on the determinants of uncertainty. A total of six second-tier network types with different formation conditions and potential roles in the project are characterized.

Research limitations/implications

Analyzing the prerequisites of strategic network formation and examining the characteristics of various networks (that are either planned, taking shape or existing between the companies) in this specific context creates a basis for further study of network formation over network levels.

Practical implications

The formation of strategic networks is critical for many actors in the construction and related industries who are willing to participate in large projects. With the help of our findings, managers are able to define opportunities to orchestrate early phase network formation processes in uncertain circumstances, such as megaprojects.

Originality/value

The contribution of this paper lies in the close examination of strategic network formation from the second-tier actor perspective under circumstances of high uncertainty related to the early phases of megaprojects. Likewise, the illustration of different types of evolving nets in different phases of uncertain projects offers a contribution to the present discussion on strategic nets.
Empathy, nonverbal immediacy, and salesperson performance: the mediating role of adaptive selling behavior
Authors: Limbu Yam B. , Jayachandran C. , Babin Barry J. , Peterson Robin T.
Published: July 2016

Purpose

Previous studies that examined the role of empathy and nonverbal immediacy on business-to-business (B2B) salesperson performance is limited in scope and yielded inconclusive evidence. Grounded in Plank and Greene’s (1996) framework of salesperson effectiveness, this paper aims to empirically investigate the mediating role of adaptive selling behavior through which empathy and nonverbal immediacy influence sales force performance and the form of empathy (cognitive or affective) that has the most beneficial role in improving relationship (versus outcome) salesperson performance.

Design/methodology/approach

Using cross-sectional data that were collected from 422 pharmaceutical sales representatives, this study used structural equation modeling to test the hypothesized relationships.

Findings

Adaptive selling behavior mediates the effect of perspective taking empathy and empathic concern on relationship performance. However, the impact of empathy on outcome performance is not significant through adaptive selling behavior, but perspective taking empathy has a direct influence on outcome performance. Contrary to expectations, nonverbal immediacy is not mediated by adaptive selling behavior but has a direct and positive impact on relationship performance.

Research limitations/implications

The results of this study have several implications for recruitment, training and assessment of salespeople in a B2B context. Based on the empirical evidence, it is highlighted that firms may use different forms of empathy and nonverbal cues to promote adaptive selling behavior that impact sales force performance (i.e. outcome or relationship).

Originality/value

To the authors’ knowledge, this is the first study which simultaneously examines the mediating role of adaptive selling behavior in the relationship between three antecedent variables that relate to sales force empathy and nonverbal communication (i.e. perspective taking empathy, empathic concern and nonverbal immediacy) and two aspects of B2B sales performance (relationship and outcome).
The role and impact of firm’s strategic orientations on launch performance: significance of relationship orientation
Authors: Matikainen Minna , Terho Harri , Parvinen Petri , Juppo Anne
Published: July 2016

Purpose

This study examines the role and relative impact of market orientation, product orientation and relationship orientation on new product launch performance, investigating product advantage and market-based assets as alternative mediating mechanisms, which link these strategic orientations to launch performance.

Design/methodology/approach

Survey data from the pharmaceutical industry are used to test hypotheses in the research model using partial least squares modeling.

Findings

Findings show that while each examined strategic orientation relates positively to launch performance, their performance effects and related mechanisms vary significantly. Results demonstrate a firm’s relationship orientation is the strongest predictor of launch performance, and accumulated market-based assets represent an alternative relational mediator besides product advantage linking firms’ orientations and launch performance.

Research limitations/implications

The empirical study is based on cross-sectional data collected in one specific industry sector. The authors encourage researchers to confirm the key findings in different industry and other contextual settings.

Practical implications

New product launch can be effectively managed as a relational activity. Firms benefit from paying explicit attention to strategic orientations and relationships. Especially, top management should foster a relationship-oriented organizational culture, develop relational competences and fully use the firm’s accumulated market-based assets for increased launch performance.

Originality/value

The study extends knowledge on the role of strategic orientations in launch performance by highlighting the significance of relationship orientations and providing novel knowledge on the key mediating mechanisms between strategic orientations and launch performance.
Collaborative culture and relationship strength roles in collaborative relationships: a supply chain perspective
Authors: Kumar Gopal , Banerjee Rabindra Nath , Meena Purushottam Lal , Ganguly Kunal
Published: July 2016

Purpose

The purpose of this paper is to model and investigate collaborative culture and relationship strength roles in supply chain collaboration. This research highlights critical role played by culture and relationship strength in collaboration.

Design/methodology/approach

Drawing from relational view, a conceptual model is developed with the help of literature, and the model is validated with data collected in India using partial least squares method.

Findings

Results and analyses revealed that culture and relationship strength significantly and strongly influence each collaborative activity. The relationship strength fully mediates between collaborative culture and supply chain performance. The research also finds that the relationship strength partially mediates between collaborative culture and market-based information sharing, operational resource planning and sharing. In the long-term, collaborative culture drives relationship strength and the element enhances collaborative activities.

Originality/value

This research attempted to explore collaborative culture and relationship strength which are crucial for collaborative relationship. Many mediation effects are studied which increase the understanding and give insights for its implementation. Its theoretical and practical implications are highlighted. This knowledge has enough potential to lead collaborative relationships towards success.
Opportunities and opportunism with high-status B2B partners in emerging economies
Authors: Gould A. Noel , Liu Annie H. , Yu Yang
Published: July 2016

Purpose

This study examines the potential of foreign business-to-business (B2B) firms to select high-status local partners in emerging markets to achieve positive relationship outcomes. Because a domestic firm’s high status may also promote opportunism, the study also examines if the foreign B2B firms may mitigate such behavior through either or both transaction-specific investments (TSIs) and socialization.

Design/methodology/approach

The research is conducted via a model that suggests a positive correlation between high local partner status and the focal relationship outcomes and the moderating effects of structural TSIs and social governance systems. The model was developed and empirically tested using data collected from 96 foreign firms operating in China.

Findings

Using multiple regressions, the findings suggest that foreign B2B firms are likely to achieve more beneficial relationship outcomes with high-status local partners. Standing alone, foreign B2B firms’ TSIs mitigate the positive relationship outcomes, whereas their socialization with the high-status partners enhances the beneficial outcomes. Most importantly, combining socialization with TSIs increases beneficial outcomes.

Research limitations/implications

This study adds to B2B marketing, status theory and the application of transaction cost economics (TCE) and social exchange theory to foreign-local B2B exchange relationships in emerging markets. The findings confirm the attractiveness of high status in emerging markets by exploring how the selection, formation and chosen B2B governance processes may lead to competing outcomes of opportunism or success. Future research will benefit from simultaneously securing data from both sides of the dyad.

Practical implications

The paper suggests that foreign B2B firms consider high status as a key criterion in selecting local partners in emerging markets and the importance of managing high-status partners’ potential opportunism by effective governance mechanisms.

Originality/value

This study is one of the first to apply and explore the workings of status theory in the foreign-local B2B partner selection process and relationship outcomes in emerging markets and thereby contributes to B2B marketing, status theory and both TCE and social exchange theories in the focal foreign-local B2B context.
Whole grain foods: is sensory liking related to knowledge, attitude, or intake?
Authors: Magalis Robin M. , Giovanni Maria , Silliman Kathryn
Published: July 2016

Purpose

The health benefits of whole grains are well established, yet intake remains below recommendations. Knowledge and familiarity with whole grains may increase short-term intake, but sensory properties can limit consumption. These factors usually are researched separately, thus, this study aims to explore the relationships among sensory liking, knowledge, attitudes and intake.

Design/methodology/approach

This cross-sectional study had 69 college students participate in four tasks: sensory liking of whole vs refined grain bread, rice, pasta and tortillas; bitter taster status; knowledge and attitudes; and intake of whole grains.

Findings

Whole wheat bread and tortillas were liked, as well as their refined grain counterparts. However, white rice and pasta were liked significantly more than the whole grain products (p < 0.05), which are less familiar to most people. Higher consumers of whole grain foods preferred those samples to the refined product for some sensory attributes (p < 0.05). Bitter taster status was not related to sensory preferences. Understanding and recognition of whole grains was low, but attitudes were generally positive. Whole grain intake was overestimated by the food frequency questionnaire because of problems with the instrument and also subjects’ lack of understanding about these foods.

Research limitations/implications

The link between preference and consumption warrants further study. The survey used to measure whole grain intake was a limitation and demonstrates the need for an accurate and efficient tool. Although knowledge about whole grains is limited, the positive attitudes expressed by participants can strategically inform outreach. If people believe that they consume more whole grains than they actually do, they may have a false sense of security. Further research with different age groups and a wider variety of foods is needed.

Practical implications

Participants overestimated their consumption of whole grain foods, indicating that consumers may think that they are meeting recommended amounts but they are actually deficient in whole grain intake; thus, improved education and promotional efforts are needed.

Originality/value

Few studies examine the inter-relationships among sensory preference, bitter taster status, knowledge, attitude and intake of whole grains.
Retention of bioactive compounds in fresh fenugreek leaves during storage under modified atmosphere packaging
Authors: Sidhu Gagandeep Kaur , Kaur Preetinder , Singh Manpreet
Published: July 2016

Purpose

Fenugreek (Trigonella foenum-graecum) leaves have received an enormous demand due to their uses in traditional Indian preparations. It is a green leafy vegetable that is highly perishable in nature, due to high respiration rate; consequently, sensory as well as nutrient loss occurs at a very high rate. The aim of this research was to enhance the shelf life of fresh fenugreek leaves under modified atmosphere and determine the effect of different physiochemical parameters on storability of fenugreek leaves.

Design/methodology/approach

Fresh fenugreek leaves were stored in polypropylene (PP) film package under four different treatments, viz., T1: perforated (one perforation), T2: perforated (two perforation, 0.3 mm each), T3: non-perforated and T4: control sample. The control samples were kept in packages under ambient conditions. All packed samples were stored at 15°C temperature and 75 per cent relative humidity (RH). The quality was determined on the basis of retention of pigments, flavonoids, antioxidants, ascorbic acid and total phenols. The sensory evaluation of the stored samples was also carried out at regular intervals.

Findings

The results of this study indicated that the quality of fresh fenugreek leaves in PP (34 μm) non-perforated package (T3) stored at 15°C and 75 per cent RH was superior to those packed under other treatments on the basis of color retention, β-carotene, ascorbic acid, 2,2-diphenyl-1-picrylhydrazyl, total phenols and overall acceptability. The produce could be safely stored for 9 days without any adverse effect on bioactive compounds.

Originality/value

Factors leading to deterioration of quality of fresh fenugreek leaves like pigments and phenolic content were largely influenced by in-pack gaseous atmosphere inside the polymeric film packages. Modified atmosphere packaging with different treatments for enhancing shelf life and retention of bioactive compound of fenugreek was carried out in the work.
In vitro digestibility and pasting properties of epichlorohydrin modified cassava starch
Authors: Horianski Marta Aurelia , Peralta Juan Manuel , Brumovsky Luis Alberto
Published: July 2016

Purpose

The purpose of this study was to analyze the influence of epichlorohydrin (ECH) concentration and reaction time on the food-grade resistant starch production and its pasting properties by using native cassava starch of Misiones-Argentina origin.

Design/methodology/approach

Cassava starch was modified using ECH (0.30 and 0.15 per cent) during 4 or 8 h. Digestibility was evaluated by determining resistant starch as total dietary fiber. Pasting properties and the cross-linking degree were studied using a micro-viscoamylograph (Brabender).

Findings

Resistant starch content was not influenced by ECH concentration and reaction time. Cross-linking was detected at higher reaction times (8 h) and ECH concentrations (0.30 per cent), where a decrease in viscosity peaks by more than 80 per cent was observed. Both pasting temperature and breakdown were increased, whereas a decrease in retrogradation was detected.

Practical implications

Starches can be suitable for different food applications. This is because of the ability to modify its pasting properties and the invariability of the in vitro digestibility of cassava starch as a result of using ECH (at concentrations approved by local and regional legislation) and reaction times of 4 and 8 h.

Originality/value

Information related to the modification of cassava starch using ECH is scarce or not available nowadays in literature.
Effect of different thistle flower ecotypes as milk-clotting in Serra da Estrela cheese
Authors: Correia Paula , Vítor André , Tenreiro Marlene , Correia Ana Cristina , Madanelo João , Guiné Raquel
Published: July 2016

Purpose

Thistle flower (Cynara cardunculus) aqueous extracts, as rich source of milk-clotting peptidases, have been widely used for cheeses marketed under the Registry of the Protected Designation of Origin, as it is the case of Serra da Estrela cheese, manufactured from raw ewes’ milk and without addition of any commercial starter culture. This paper aims at studying the influence of six different ecotypes of thistle flowers in cheese properties during the ripening and of final products.

Design/methodology/approach

Cheeses were produced with different thistle flower extracts and then the clotting time, weight and colour of cheeses, as well as texture properties and sensorial characteristics, were evaluated.

Findings

The clotting time varied from 47 to 66 min, and the weight loss along ripening varied between 32 and 40 per cent. There was some influence of thistle flower ecotype on the colour during ripening and in the final product. The results of texture analysis revealed significant differences between the thistle ecotypes: crust firmness varying from 2.4 to 5.6 N; inner firmness from 0.82 to 1.82 N; stickiness from −0.5 to −1.60 N; adhesiveness from −3.0 to −11.3 N.s; and Ecotype C was particularly distinguishable. Sensorial evaluation revealed differences among the cheeses, with Ecotype C receiving the highest score for global appreciation.

Originality/value

The usage of different extracts of thistle flower to produce Serra da Estrela cheese with different properties is a novelty, and it allows the possibility of manipulating this parameter in the future so as to produce cheeses with specific characteristics, addressed to different consumer targets.
Success despite the stress: violet‐green swallows increase glucocorticoids and maintain reproductive output despite experimental increases in flight costs
Authors: Rivers James W. , Newberry Gretchen N. , Schwarz Carl J. , Ardia Daniel R.
Published: July 2016

Glucocorticoid steroid hormones play a central role in regulating the metabolic state of animals, especially when they cope with unanticipated stressors in their environment. The cort‐adaptation hypothesis predicts that baseline concentrations of glucocorticoids are adjusted upward to match energetic needs and promote fitness when individuals are faced with physiological challenges, including those associated with reproduction.

We tested the cort‐adaptation hypothesis in the violet‐green swallow (Tachycineta thalassina) by experimentally increasing flight costs during the offspring rearing period. Individual females were assigned to one of three treatments: light feather clipping (removal of four wing feathers), heavy feather clipping (removal of eight wing feathers) or a sham‐clip control.

We measured baseline corticosterone and body mass immediately prior to implementing treatments during the offspring rearing period and then 10 days after initial manipulations took place. We also quantified risk‐taking behaviour, offspring feeding rate and the number of offspring fledged. Finally, we examined how treatments influenced offspring phenotype via measurements of nestling body mass and baseline corticosterone, as both measures have been associated with post‐fledging survival.

We found that handicapped females significantly increased baseline corticosterone between the two sampling periods, with the magnitude of change in the light clipping and heavy clipping treatments 2·5× and 6·1× greater than controls, respectively. All individuals lost mass between the two sampling periods, but the degree of loss was greater for females in both clipping treatments relative to unmanipulated controls.

In contrast, we found no evidence of treatment differences in female risk‐taking, offspring provisioning or in the number of offspring fledged. Offspring raised by females in both handicapped treatments did have significantly elevated baseline corticosterone relative to those in control broods, but we detected no treatment differences in offspring body mass.

Our study found that handicapped females increased circulating glucocorticoids and were able to maintain critical parental care behaviours and raise a similar number of offspring as unmanipulated controls. Thus, increases in baseline cort of handicapped females appeared to have allowed them to maintain fitness despite increased physiological challenges, providing support for the cort‐adaptation hypothesis.

A Lay Summary is available for this article.
Root heterogeneity along an arctic elevational gradient: the importance of resolution
Authors: Träger Sabrina , Wilson Scott D.
Published: July 2016

Spatial heterogeneity affects plant performance and is influenced by plants, but the scale at which fine roots react to or generate spatial heterogeneity has received little attention. Fine roots might be expected to respond to heterogeneity at a scale comparable to their diameter (mm), but studies to date have been conducted at much coarser resolutions (cm – m). Here we quantify root heterogeneity in contrasting habitats with special attention to the influence of resolution.

We measured fine root length heterogeneity at resolutions ranging from 1 to 300 mm2, at four elevations along an arctic alpine gradient from 500 m a.s.l. (forest) to 1100 m (tundra). We calculated the magnitude of heterogeneity as the coefficient of variation of root length, and the scale of heterogeneity using semivariance analysis.

The magnitude of heterogeneity was about twofold greater at fine than coarse resolution. Further, the magnitude of heterogeneity was generally greatest at the highest elevation, suggesting that soil at 1100 m was less evenly occupied by plant roots than soils at lower elevations. The exception to this was at the 1 mm2 resolution, for which the magnitude of heterogeneity did not vary with elevation, possibly because heterogeneity at this scale is related to ecophysiological processes common to all vegetation types.

The scale of root length heterogeneity increased significantly with resolution coarseness, suggesting that roots respond to or generate patchiness at small scales that have not previously been examined. In contrast, the scale of heterogeneity did not vary significantly with elevation and the accompanying turnover in growth form.

Our results suggest that roots in four vegetation types respond to or generate very fine scales of spatial heterogeneity, including scales much smaller than those that have previously been examined. Both the magnitude and scale of heterogeneity varied with sampling resolution, suggesting resolutions as small as a few millimetres are relevant to studies of spatial root interactions and below‐ground processes.
Frequency‐domain waveform modelling and inversion for coupled media using a symmetric impedance matrix
Authors: Shin Jungkyun , Jun Hyunggu , Min Dong‐Joo , Shin Changsoo
Published: July 2016

To simulate the seismic signals that are obtained in a marine environment, a coupled system of both acoustic and elastic wave equations is solved. The acoustic wave equation for the fluid region simulates the pressure field while minimizing the number of degrees of freedom of the impedance matrix, and the elastic wave equation for the solid region simulates several elastic events, such as shear waves and surface waves. Moreover, by combining this coupled approach with the waveform inversion technique, the elastic properties of the earth can be inverted using the pressure data obtained from the acoustic region. However, in contrast to the pure acoustic and elastic cases, the complex impedance matrix for the coupled media does not have a symmetric form because of the boundary (continuity) condition at the interface between the acoustic and elastic elements. In this study, we propose a manipulation scheme that makes the complex impedance matrix for acoustic–elastic coupled media to take a symmetric form. Using the proposed symmetric matrix, forward and backward wavefields are identical to those generated by the conventional approach; thus, we do not lose any accuracy in the waveform inversion results. However, to solve the modified symmetric matrix, LDLT factorization is used instead of LU factorization for a matrix of the same size; this method can mitigate issues related to severe memory insufficiency and long computation times, particularly for large‐scale problems.
Diversity of terrestrial isopods in the northern Tunisian wetlands
Authors: Khemaissia Hajer , Jelassi Raja , Touihri Moez , Souty‐Grosset Catherine , Nasri‐Ammar Karima
Published: July 2016

To evaluate the influence of wetland types on the distribution of terrestrial isopods, species richness, relative abundance and diversity indices were studied in the supralittoral zone of 95 wetlands in the north‐western of Tunisian dorsal, belonging to six types: lagoon, hill reservoir, river, dam, lake and sebkha. We tested the following hypothesis: (i) is isopod diversity influenced by wetland types? (ii) is isopod diversity influenced by bioclimatic zones? and (iii) what are the environmental factors influencing isopod distribution? A total of 3255 individuals belonging to twenty species of terrestrial isopods were captured. Species richness differs significantly between wetland types. A highly significant positive relationship between species richness and both humidity and altitudinal gradient was described. The dendrogram of similarities showed a divergence of the lagoons compared to the remaining wetland types.
Statistical power of replicated helicopter surveys in southern African conservation areas
Authors: Reilly Brian K. , van Hensbergen Hubertus J. , Eiselen Riette J. , Fleming Peter J. S.
Published: July 2016

Understanding the ecology of large ungulates in southern Africa requires accurate and precise measures of population size. Recovery or exploitation of ungulates in reserves is currently instigated when population size changes exceed 15% per annum, but monitoring is usually undertaken with single counts from helicopters, for which precision and the power to detect change are untested. In essence, power being the strength of a monitoring result in showing change over time. Retrospective power analysis is a useful technique to investigate the variability of single‐count aerial surveys. Using replicated helicopter‐based counts of southern African ungulates and post hoc analysis, we investigated the power of currently used single‐count surveys across five common ungulate species and 11 wildlife reserves. We expected high variability in count data and set α = 0.1 and 0.2 (α being the type I error rate), and asked two questions: ‘How much does power vary in replicated aerial counts of southern African wildlife across reserves and species?’ and ‘Can current single‐count aerial surveys detect population changes in response to management actions or are the statistical errors intractable?’ Single counts were mostly unreliable; only one of 42 had sufficient power to detect meaningful changes in population size or their trends at α = 0.1, and only three had sufficient power at α = 0.2. Power varied widely according to species (e.g. warthog, median power at α = 0.1; 0.12–0.37: blue wildebeest, median power at α = 0.1; 0.23–0.74), and, within species, between replicates and reserves. Our retrospective calculations demonstrated insensitivity and ineffectiveness in most currently applied single counts from helicopters. Consequently, it is impossible to interpret the effects of ungulate conservation actions on many southern African reserves. Retrospective power analyses enables determination of which previous aerial surveys were useful for population assessment and adaptive management, and which should be discarded. We recommend that prospective power analyses are undertaken to determine future helicopter survey sample size and replication requirements, especially in small reserves.
Aspect and slope as determinants of vegetation composition and soil properties in coastal forest backdunes of Eastern Cape, South Africa
Authors: Ruwanza Sheunesu , Shackleton Charlie M.
Published: July 2016

Coastal sand dune ecosystems are subjected to many stress and disturbance factors that are particularly high in the foredunes compared to the backdunes. Although a few studies have been conducted on eastern coastline sand dunes of South Africa, none have examined the relationship between aspect and slope on vegetation composition and soil properties of coastal forest backdunes. Vegetation and soil sampling were conducted in 11 transects, each with four plots measuring 10 × 10 m, located on the seaward and landward sides and on middle and lower slopes of backdunes of Bathurst coastal forest. A total of 39 species were identified, of which 23 were trees and shrubs, thirteen were forbs and three were grasses. The data show that both aspect and slope had limited influence on vegetation community assemblage and soil properties, but had significant effects on individual species distribution. There was a grass‐dominated community on the middle slope and a tree‐ and shrub‐ dominated community on the lower slope. These two plant communities act as the required coastal forest ecosystem engineer driving variability in soil properties between the slopes, the most prominent being high soil nutrients and moisture in the lower slopes compared to the middle slopes.
Urethral diverticulectomy with Martius labial fat pad interposition improves symptom resolution and reduces recurrence
Authors: Malde Sachin , Sihra Néha , Naaseri Sahar , Spilotros Marco , Solomon Eskinder , Pakzad Mahreen , Hamid Rizwan , Ockrim Jeremy L. , Greenwell Tamsin J.
Published: July 2016

Objective

To assess the presenting features and medium‐term symptomatic outcomes in women having excision of urethral diverticulum with Martius labial fat pad (MLFP) interposition.

Patients and Methods

We reviewed our prospective database of all female patients having excision of a symptomatic urethral diverticulum between 2007 and 2015. Data on demographics, presenting symptoms and clinical features were collected, as well as postoperative outcomes.

Results

In all, 70 women with a mean (range) age of 46.5 (24–77) years underwent excision of urethral diverticulum with MLFP interposition. The commonest presenting symptoms were a urethral mass (69%), urethral pain (61%), and dysuria (57%). Pre‐existing stress urinary incontinence (SUI) was present in 41% (29) of the women. After surgery, at a mean (SD) of 18.9 (16.4) months follow‐up (median 14 months), complete excision of urethral diverticulum was achieved in all the women, with resolution of urethral mass, dysuria and dyspareunia in all, and urethral pain in 81%. Immediately after surgery, 10 (24%) patients reported de novo SUI, which resolved with time and pelvic floor muscle training such that at 12 months only five (12%) reported continued SUI. There was one symptomatic diverticulum recurrence (1.4%).

Conclusions

The commonest presenting symptom of a female urethral diverticulum is urethral pain followed by dysuria and dyspareunia. Surgical excision with MLFP interposition results in complete resolution of symptoms in most women. The incidence of persistent de novo SUI in an expert high‐volume centre is 12%.
Robotic perineal radical prostatectomy and pelvic lymph node dissection using a purpose‐built single‐port robotic platform
Authors: Ramirez Daniel , Maurice Matthew J. , Kaouk Jihad H.
Published: July 2016

Objectives

To describe the features of the novel, purpose‐built da Vinci model SP1098 single‐port robotic platform and to describe a step‐by‐step approach for perineal prostatectomy and pelvic lymph node dissection in a cadaver model.

Methods

Three single‐port robotic radical perineal prostatectomies and two pelvic lymph node dissections were performed on three male cadavers to assess the feasibility of the SP1098 da Vinci robotic platform. The steps in the procedure included division of the rectourethralis muscle, splitting of the levator ani muscles bilaterally, opening of Denonvilliers fascia with dissection of the seminal vesicles, apical dissection and urethral division, anterior and lateral dissection with ligation of prostatic pedicles, bilateral pelvic lymph node dissection, and creation of the new vesico‐urethral anastomosis. The main outcomes assessed were operating time per step, total operating time, intra‐operative complications and need for conversion to conventional or open techniques.

Results

No conversions were required. No intra‐operative complications were seen. The median (range) operating time for performing single‐port robotic radical perineal prostatectomy and pelvic lymph node dissection was 210 (180–240) min.

Conclusions

We have shown the feasibility and efficacy of a novel, purpose‐built robotic system in performing single‐port radical perineal prostatectomy and describe, for the first time, the feasibility of robotic perineal lymph node dissection. This single‐port system will facilitate single‐port applications and allow surgeons to perform major urological operations via a small, single incision while preserving triangulation and optics, and eliminating clashing between instruments. Future clinical studies are needed to support these encouraging outcomes.
Predicting complications in partial nephrectomy for T1a tumours: does approach matter?
Authors: Ramirez Daniel , Maurice Matthew J. , Caputo Peter A. , Nelson Ryan J. , Kara Önder , Malkoç Ercan , Kaouk Jihad H.
Published: July 2016

Objectives

To assess differences in complications after robot‐assisted (RAPN) and open partial nephrectomy (OPN) among experienced surgeons.

Patients and Methods

We identified patients in our institutional review board‐approved, prospectively maintained database who underwent OPN or RAPN for management of unifocal, T1a renal tumours at our institution between January 2011 and August 2015. The primary outcome measure was the rate of 30‐day overall postoperative complications. Baseline patient factors, tumour characteristics and peri‐operative factors, including approach, were evaluated to assess the risk of complications.

Results

Patients who underwent OPN were found to have a higher rate of overall complications (30.3% vs 18.2%; P = 0.038), with wound complications accounting for the majority of these events (11.8% vs 1.8%; P < 0.001). Multivariable logistic regression analysis showed the open approach to be an independent predictor of overall complications (odds ratio 1.58, 95% confidence interval 1.03–2.43; P = 0.035). Major limitations of the study include its retrospective design and potential lack of generalizability.

Conclusions

The open surgical approach predicts a higher rate of overall complications after partial nephrectomy for unifocal, T1a renal tumours. For experienced surgeons, the morbidity associated with nephron‐sparing surgery may be incrementally improved using the robot‐assisted approach.
Oligodendroglial deletion of ESCRT‐I component TSG101 causes spongiform encephalopathy
Authors: Walker Will P. , Oehler Abby , Edinger Aimee L. , Wagner Kay‐Uwe , Gunn Teresa M.
Published: July 2016

Background Information

Vacuolation of the central nervous system (CNS) is observed in patients with transmissible spongiform encephalopathy, HIV‐related encephalopathy and some inherited diseases, but the underlying cellular mechanisms remain poorly understood. Mice lacking the mahogunin ring finger‐1 (MGRN1) E3 ubiquitin ligase develop progressive, widespread spongiform degeneration of the CNS. MGRN1 ubiquitinates and regulates tumour susceptibility gene 101 (TSG101), a central component of the endosomal trafficking machinery. As loss of MGRN1 is predicted to cause partial TSG101 loss‐of‐function, we hypothesised that CNS vacuolation in Mgrn1 null mice may be caused by the accumulation of multi‐cisternal endosome‐like ‘class E’ vacuolar protein sorting (vps) compartments similar to those observed in Tsg101‐depleted cells in culture.

Results

To test this hypothesis, Tsg101 was deleted from mature oligodendroglia in vivo. This resulted in severe spongiform encephalopathy, histopathologically similar to that observed in Mgrn1 null mutant mice but with a more rapid onset. Vacuoles in the brains of Tsg101‐deleted and Mgrn1 mutant mice labelled with endosomal markers, consistent with an endosomal origin. Vacuoles in the brains of mice inoculated with Rocky Mountain Laboratory (RML) prions did not label with these markers, indicating a different origin, consistent with previously published studies that indicate RML prions have a primary effect on neurons and cause vacuolation in an MGRN1‐independent manner. Oligodendroglial deletion of Rab7, which mediates late endosome‐to‐lysosome trafficking and autophagosome–lysosome fusion, did not cause spongiform change.

Conclusions

Our data suggest that the formation of multi‐cisternal ‘class E’ vps endosomal structures in oligodendroglia leads to vacuolation.

Significance

This work provides the first evidence that disrupting multi‐vesicular body formation in oligodendroglia can cause white matter vacuolation and demyelination. HIV is known to hijack the endosomal sorting machinery, suggesting that HIV infection of the CNS may also act through this pathway to cause encephalopathy.
Activation of inflammatory immune gene cascades by lipopolysaccharide (LPS) in the porcine colonic tissue ex-vivo model
Authors: Bahar B , O'Doherty J V , Vigors S , Sweeney T
Published: July 2016

The technique of challenging postmortem tissue explants with inflammation inducer such as lipopolysaccharide (LPS) followed by gene expression analysis is used widely for evaluating the immune-suppressing effect of bioactives. Using porcine colonic tissue as an ex-vivo model of mammalian intestinal gut, this study evaluated the effect of incubation time on the integrity of gene transcripts and activation of inflammatory immune gene cascade by LPS treatment. Post-slaughter colon was removed surgically and explants were incubated for 0, 3, 6 and 12 h and the abundance of mRNA transcripts of a panel of 92 immune genes were evaluated using quantitative polymerase chain reaction (qPCR) arrays. The mRNA transcripts were highly intact after 0 and 3 h of incubation; however, after 6 h the degradation was clearly evident. Following 3 h incubation, 98·8% and 100% mRNA transcripts were detectable in the colonic tissue harvested from weaned and mature pigs, respectively. In the explants of weaned piglets, LPS treatment activated inflammatory signalling pathways [high mobility group B1 (HMGB1), dendritic cell maturation, interleukin (IL)-6, IL-8, IL-17F], while these pathways were inhibited by dexamethasone treatment. Activations of inflammatory genes were also evident in the explants collected from the mature pigs subjected to ex-vivo incubation for 3 h in the absence or presence of LPS. It is concluded that the colonic explant remains physiologically viable and responsive to immunological challenge for up to 3 h ex-vivo.