bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Sexual Risk Behavior Among Study Participants in the TDF2 PrEP Study Among Heterosexual Adults in Botswana
Authors: Gust Deborah A. , Soud Fatma , Hardnett Felicia P. , Malotte Charles K. , Rose Charles , Kebaabetswe Poloko , Makgekgenene Lebogang , Henderson Faith , Paxton Lynn , Segolodi Tebogo , Kilmarx Peter H.
Published: August 2016

Objective:

Among participants of a clinical trial to test the efficacy of tenofovir/emtricitabine in protecting heterosexual men and women living in Botswana from HIV infection, the aim was to determine (1) if sexual risk behavior, specifically condomless sex acts and number of sex partners, changed over time, (2) factors associated with condomless sex acts and number of sex partners, and (3) the effect of participant treatment arm perception on risk behavior to address the possibility of risk compensation.

Methods:

A longitudinal modeling of rates of risk behaviors was used to determine if the rate of condomless sex acts (#acts/person) and rate of sex partners (#partners/person) changed over time and which factors were associated with behavior change.

Results:

One thousand two hundred participants were analyzed over 1 year. There was a 25% decrease in the rate of sex partners among participants sexually active in the last 30 days. The rate of reported condomless sex acts was greater for males [rate ratio (RR) = 1.34; confidence interval (CI): 1.07 to 1.67] and participants whose sexual debut in years was ≤15 years of age (RR = 1.65; CI: 1.14 to 2.38) and 16–17 (RR = 1.68; CI: 1.22 to 2.31) compared with those ≥20 years. Rate of reported sex partners was greater for males (RR = 3.67; CI: 2.86 to 4.71) and participants whose age at sexual debut in years was ≤15 (RR = 2.92; CI: 2.01 to 4.22) and 16–17 (RR = 2.34; CI: 1.69 to 3.24) compared with those ≥20. There was no effect of participant treatment arm perception on risk behavior.

Conclusions:

Our study of preexposure prophylaxis to prevent HIV infection found no evidence of risk compensation which may have been due to participants' motivations to reduce their risk behaviors and risk-reduction counseling.
Marker of Endothelial Dysfunction Asymmetric Dimethylarginine Is Elevated in HIV Infection but Not Associated With Subclinical Atherosclerosis
Authors: Haissman Judith M. , Haugaard Anna K. , Knudsen Andreas , Kristoffersen Ulrik S. , Seljeflot Ingebjørg , Pedersen Karin K. , Lebech Anne-Mette , Hasbak Philip , Kjær Andreas , Ostrowski Sisse R. , Gerstoft Jan , Trøseid Marius , Nielsen Susanne D.
Published: August 2016

Background:

Cardiovascular disease contributes to excess morbidity and mortality in HIV infection, and endothelial dysfunction may contribute to this pattern. We aimed to determine the endothelial function in treated and untreated HIV-infected individuals and investigate potential associations with viral replication, immune activation, coagulation, platelet function, and subclinical atherosclerosis.

Methods:

Asymmetric dimethylarginine (ADMA, marker of endothelial dysfunction) and soluble CD14 (sCD14, marker of monocyte activation) were measured in plasma from two previously established cross-sectional cohorts: cohort A including 50 untreated and 50 antiretroviral therapy (ART)–treated HIV-infected individuals with previously assessed coagulation and platelet function and cohort B including 105 HIV-infected individuals on ART and 105 uninfected controls with previously assessed coronary artery calcium score, myocardial perfusion defects, and carotid intima–media thickness.

Results:

Concentrations of ADMA were higher in HIV-infected individuals compared with uninfected controls, and higher ADMA was found in ART-treated compared with untreated HIV-infected individuals. ADMA was associated with viral load, sCD14, D-dimer, and low CD4+ T-cell count in untreated HIV infection. Only viral load remained significant in multivariate analyses. In ART-treated HIV-infected individuals, ADMA was not associated with coronary artery calcium score, myocardial perfusion defects, or intima–media thickness.

Conclusions:

Evidence of endothelial dysfunction was found in HIV infection and in untreated compared with treated HIV infection. In untreated HIV infection, the main driver of endothelial dysfunction was viral replication. Importantly, in treated HIV infection, ADMA was not associated with subclinical atherosclerosis. Thus, our data question the potential of ADMA as a useful biomarker of early atherosclerosis in treated HIV infection.
Precursor Forms of Vitamin D Reduce HIV-1 Infection In Vitro
Authors: Aguilar-Jimenez Wbeimar , Villegas-Ospina Simon , Gonzalez Sandra , Zapata Wildeman , Saulle Irma , Garziano Micaela , Biasin Mara , Clerici Mario , Rugeles Maria T.
Published: August 2016

Background:

Although the anti-HIV-1 effects of vitamin D (VitD) have been reported, mechanisms behind such protection remain largely unexplored.

Methods:

The effects of two precursor forms (cholecalciferol/calciol at 0.01, 1 and 100 nM and calcidiol at 100 and 250 nM) on HIV-1 infection, immune activation, and gene expression were analyzed in vitro in cells of Colombian and Italian healthy donors. We quantified levels of released p24 by enzyme-linked immunosorbent assay, of intracellular p24 and cell-surface expression of CD38 and HLA-DR by flow cytometry, and mRNA expression of antiviral and immunoregulatory genes by real-time reverse transcription-polymerase chain reaction.

Results:

Cholecalciferol decreased the frequency of HIV-1-infected p24+CD4+ T cells and levels of p24 in supernatants in a dose-dependent manner. Moreover, the CD4+CD38+HLA-DR+ and CD4+CD38−HLA-DR+ subpopulations were more susceptible to infection but displayed the greatest cholecalciferol-induced decreases in infection rate by an X4-tropic strain. Likewise, cholecalciferol at its highest concentration decreased the frequency of CD38−HLA-DR+ but not of CD38+HLA-DR+ T-cell subsets. Analyzing the effects of calcidiol, the main VitD source for immune cells and an R5-tropic strain as the most frequently transmitted virus, a reduction in HIV-1 productive infection was also observed. In addition, an increase in mRNA expression of APOBEC3G and PI3 and a reduction of TRIM22 and CCR5 expression, this latter positively correlated with p24 levels, was noted.

Conclusions:

VitD reduces HIV-1 infection in T cells possibly by inducing antiviral gene expression, reducing the viral co-receptor CCR5 and, at least at the highest cholecalciferol concentration, by promoting an HIV-1-restrictive CD38+HLA-DR− immunophenotype.
Chronic HIV-1 Infection Impairs Superantigen-Induced Activation of Peripheral CD4+CXCR5+PD-1+ Cells, With Relative Preservation of Recall Antigen–Specific Responses
Authors: Nicholas Katherine J. , Flaherty David K. , Smith Rita M. , Sather D. Noah , Kalams Spyros A.
Published: August 2016

Peripheral CD4+CXCR5+PD-1+ T cells are a putative circulating counterpart to germinal center T follicular helper (TFH) cells. They show both phenotypic and functional similarities to TFH cells, which provide necessary help for the differentiation of B cells to antibody-secreting plasmablasts. In this study, we evaluated the frequency, phenotypes, and responses of peripheral TFH-like (pTFH) cells to superantigen and recall antigen stimulation in 10 healthy and 34 chronically infected treatment-naive HIV-1+ individuals. There was no difference in the frequency of pTFH cells between HIV+ and HIV− individuals. Surface expression of ICOS, but not CD40L, was higher on pTFH cells at baseline in HIV+ individuals. Compared with HIV− individuals, pTFH cells from HIV+ individuals had decreased maximal expression of ICOS and CD40L in response to in vitro superantigen stimulation. This decreased response did not correlate with viral control, CD4+ T-cell count, duration of infection, or the degree of neutralizing antibody breadth. Despite a decreased maximal response, pTFH responses to HIV Gag and tetanus toxoid recall antigens were preserved.
Giardia: a pathogen or commensal for children in high-prevalence settings?
Authors: Bartelt Luther A. , Platts-Mills James A.
Published: August 2016

Purpose of review

Giardia is a common intestinal parasite worldwide, and infection can be associated with clear and sometimes persistent symptomatology. However, in children in high-prevalence settings, it is not associated with or is perhaps even protective against acute diarrhea, and the association with long-term outcomes has been difficult to discern.

Recent findings

Recent studies have made progress in helping us disentangle this apparent paradox. First, prospective, well-characterized cohort studies have added to the data on the association between Giardia and diarrhea in these settings and have further characterized associations between Giardia infection and nutrition, gut function, and growth. Second, animal models have further characterized the host response to Giardia and helped elucidate mechanisms by which Giardia could impair child development. Finally, new work has shed light on the heterogeneity of human Giardia strains, which may both explain discrepant findings in the literature and help guide higher-resolution analyses of this pathogen in the future.

The true clinical impact of endemic pediatric giardiasis remains unclear, but recent prospective studies have confirmed a high prevalence of persistent, subclinical Giardia infections and associated growth shortfalls. Integrating how nutritional, microbial, metabolic, and pathogen–strain variables influence these outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite.
Reporting Guidelines for Health Care Simulation Research
Authors: Salas Eduardo
Published: August 2016

Summary Statement

This is a commentary on the reporting guidelines article and offers some food for thought on the need to include learning and instructional feature variables in the reporting process.
What can we learn about breathlessness from population-based and administrative health data?
Authors: Ekström Magnus
Published: August 2016

Purpose of review

To review the findings and methodological strengths and limitations of studies of breathlessness using population-based or routinely collected data, including the novel methodology of the registry-based randomized controlled trial (R-RCT).

Recent findings

Breathlessness severe enough to restrict activity is common and increases in the last months of life both among elderly in the community and among patients in specialized palliative care. During the last week of life, risk factors for more severe breathlessness have been identified. Patients with advanced chronic obstructive or interstitial lung disease experience more breathlessness than patients dying from lung cancer. Breathlessness often remains unrelieved or only partially relieved at the end of life.

Data from population-based or health-administrative databases can inform on the epidemiology, associated factors and the potential impact of breathlessness. Potential strengths of these data are high precision and generalizability because of large, nonselective study populations with high completeness of follow-up of outcomes such as survival. Potential limitations include residual confounding and insufficient data quality which is unaffected by increasing the sample size. The R-RCT methodology combines strengths of randomization with those of large representative databases to evaluate effectiveness in clinical care.
Contributions of military surgeons to the management of vascular trauma
Authors: Feliciano David V.
Published: August 2016

Many military trauma surgeons have helped to advance the management of vascular injuries during wartime. The five surgeons highlighted—Sir George Henry Makins, Michael E. DeBakey, Harris B. Shumacker, Jr., Carl W. Hughes, and Norman M. Rich—made significant and lasting contributions.
Thinking Socially
Authors: Crooke Pamela J. , Winner Michelle Garcia , Olswang Lesley B.
Published: August 2016

This article addresses the complexity of what it means to “be social” from the perspective of social thinking. This perspective recognizes social cognitive processing abilities as the foundation for social knowledge and, in turn, social behaviors. The article further describes variables that influence how one understands how to do what is expected in different social situations and how development, stakeholders, and context influence that process. Challenges in “being social” for individuals with autism spectrum disorders are discussed, as well as differences between behavior-based and cognitive-based therapies. Finally, an example of one Social Thinking strategy-based treatment framework, Social Behavior Mapping, is used to illustrate the essential elements of cognitive behavioral therapy.
Can Team Triage Improve Patient Flow in the Emergency Department? A Systematic Review and Meta-Analysis
Authors: Ming Thomas , Lai Aaron , Lau Pui-man
Published: August 2016

This systematic review was performed as a feasibility study for revamping the triage service of an emergency department (ED) in a district hospital. In view of the overcrowding problem that plagues EDs worldwide, we reviewed evidence from randomized controlled trials (RCTs) to determine whether ED team triage improves patient flow in comparison with single-nurse triage. We measured improvement in patient flow in terms of the reduction in length of stay (LOS) or wait time (WT) for all ED patients. Adopting the Cochrane methodology, we searched and evaluated data sources for RCTs comparing patients assessed by an ED triage team, with patients receiving single-nurse triage at the same site. The data extracted were independently reviewed by 2 authors for inclusion and quality assessment. As for risk of bias across studies, there was an overall assessment of every outcome across the included studies according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria for RCTs. In total, 2,164 studies were identified and 2,106 were excluded on the basis of title/abstract, leaving 58 articles for full assessment. Four trials (all cluster RCTs) involving 14,772 patients (165 clusters) met the inclusion criteria. On the basis of our analysis, there was no statistically significant or clinically relevant reduction of LOS and WT for all patients in these studies. One study reported death as an outcome: Relative risk was 0.34 (95% CI [0.01, 8.24]), which suggested that team triage might reduce mortality. Overall, although we have found no conclusive evidence from RCTs to support the use of team triage for improving patient flow in the ED, the results need not deter nursing managers intending to introduce team triage for improving the morale of the triage nurse. However, they may need to consider economic and organizational factors, such as resource reallocation and staff receptiveness, in implementing the new practice.
Advances in modeling and treating spinal muscular atrophy
Authors: Van Alstyne Meaghan , Pellizzoni Livio
Published: August 2016

Purpose of review

Spinal muscular atrophy (SMA) is an inherited childhood neurodegenerative disorder caused by ubiquitous deficiency of the survival motor neuron (SMN) protein – the hallmarks of which are the selective loss of motor neurons and skeletal muscle atrophy. Here, we highlight recent progress in the understanding of SMA pathology and in the development of therapeutic approaches for its treatment.

Recent findings

Phenotypic characterization of mouse models of the disease, combined with analysis of SMN restoration or depletion in a spatially and temporally controlled manner, has yielded key insights into the normal requirement of SMN and SMA pathophysiology. Increasing evidence indicates a higher demand for SMN during neuromuscular development and extends the pathogenic effects of SMN deficiency beyond motor neurons to include additional cells both within and outside the nervous system. These findings have been paralleled by preclinical development of powerful approaches for increasing SMN expression through gene therapy or splicing modulation that are now in human trials.

Along with the availability of SMN-upregulating drugs, identification of the specific cell types in which SMN deficiency induces the disease and delineation of the window of opportunity for effective treatment are key advances in the ongoing path to SMA therapy.
Maximizing the Yield of Rapid Eye Movement Sleep in the Epilepsy Monitoring Unit
Authors: Ng Marcus C.
Published: August 2016

Purpose:

Rapid eye movement (REM) sleep can help localize the epileptogenic zone in multifocal epilepsy when interictal discharges appear diffuse. However, REM sleep is reputedly rare and easily overlooked in the Epilepsy Monitoring Unit (EMU). The aims of this study are to determine the characteristics of REM sleep in a typical EMU and whether using automated artifact recognition can meaningfully enhance REM sleep detection.

Methods:

Artifact-based REM sleep detection was applied to 581 nights of EMU recording from 100 patients over 12 months. REM sleep had been manually detected at the time of recording. The index of suspicion for manual detection was raised after 6 months. Artifact-based detection was compared with manual detection, and the impact on localization was assessed.

Results:

REM sleep occurred in 77% of EMU nights. Thirty-six patients achieved REM sleep nightly and 62 patients on at least one night. Mean admission was 5.83 days. Mean REM sleep duration was 5.92 minutes over 1.88 mean nightly bouts. Raising the level of suspicion increased manual detection rates from 22.6% to 40.5%. The artifact-based detection rate was 96% and provided additional localizing information in 10% of epilepsy patients.

Conclusions:

REM sleep is common in the EMU, but bouts are few and brief. Capturing these bouts to maximize the yield of REM sleep in the EMU is made possible by automated artifact recognition whose results could enhance localization of the epileptogenic zone.
American Clinical Neurophysiology Society Guideline 7: Guidelines for EEG Reporting
Authors: Tatum William O. , Olga Selioutski , Ochoa Juan G. , Munger Clary Heidi , Cheek Janna , Drislane Frank , Tsuchida Tammy N.
Published: August 2016

This EEG Guideline incorporates the practice of structuring a report of results obtained during routine adult electroencephalography. It is intended to reflect one of the current practices in reporting an EEG and serves as a revision of the previous guideline entitled “Writing an EEG Report.” The goal of this guideline is not only to convey clinically relevant information, but also to improve interrater reliability for clinical and research use by standardizing the format of EEG reports. With this in mind, there is expanded documentation of the patient history to include more relevant clinical information that can affect the EEG recording and interpretation. Recommendations for the technical conditions of the recording are also enhanced to include post hoc review parameters and type of EEG recording. Sleep feature documentation is also expanded upon. More descriptive terms are included for background features and interictal discharges that are concordant with efforts to standardize terminology. In the clinical correlation section, examples of common clinical scenarios are now provided that encourages uniformity in reporting. Including digital samples of abnormal waveforms is now readily available with current EEG recording systems and may be beneficial in augmenting reports when controversial waveforms or important features are encountered.
Hyperventilation in Patients With Focal Epilepsy: Electromagnetic Tomography, Functional Connectivity and Graph Theory — A Possible Tool in Epilepsy Diagnosis?
Authors: Mazzucchi Edoardo , Vollono Catello , Losurdo Anna , Testani Elisa , Gnoni Valentina , Di Blasi Chiara , Giannantoni Nadia M. , Lapenta Leonardo , Brunetti Valerio , Della Marca Giacomo
Published: August 2016

Purpose:

Hyperventilation (HV) is a commonly used electroencephalogram activation method.

Methods:

We analyzed EEG recordings in 22 normal subjects and 22 patients with focal epilepsy of unknown cause. We selected segments before (PRE), during (HYPER), and 5 minutes after (POST) HV. To analyze the neural generators of EEG signal, we used standard low-resolution electromagnetic tomography (sLORETA software). We then computed EEG lagged coherence, an index of functional connectivity, between 19 regions of interest. A weighted graph was built for each band in every subject, and characteristic path length (L) and clustering coefficient (C) have been computed. Statistical comparisons were performed by means of analysis of variance (Group X Condition X Band) for mean lagged coherence, L and C.

Results:

Hyperventilation significantly increases EEG neural generators (P < 0.001); the effect is particularly evident in cingulate cortex. Functional connectivity was increased by HV in delta, theta, alpha, and beta bands in the Epileptic group (P < 0.01) and only in theta band in Control group. Intergroup analysis of mean lagged coherence, C and L, showed significant differences for Group (P < 0.001), Condition (P < 0.001), and Band (P < 0.001). Analysis of variance for L also showed significant interactions: Group X Condition (P = 0.003) and Group X Band (P < 0.001).

Conclusions:

In our relatively small group of epileptic patients, HV is associated with activation of cingulate cortex; moreover, it modifies brain connectivity. The significant differences in mean lagged coherence, path length, and clustering coefficient permit to hypothesize that this activation method leads to different brain connectivity patterns in patients with epilepsy when compared with normal subjects. If confirmed by other studies involving larger populations, this analysis could become a diagnostic tool in epilepsy.
Unconventional high-
T
c
superconductivity in fullerides
Authors: Takabayashi Yasuhiro , Prassides Kosmas
Published: August 2016

A
3
C
60
molecular superconductors share a common electronic phase diagram with unconventional high-temperature superconductors such as the cuprates: superconductivity emerges from an antiferromagnetic strongly correlated Mott-insulating state upon tuning a parameter such as pressure (bandwidth control) accompanied by a dome-shaped dependence of the critical temperature,
T
c
. However, unlike atom-based superconductors, the parent state from which superconductivity emerges solely by changing an electronic parameter—the overlap between the outer wave functions of the constituent molecules—is controlled by the C
60
3−
molecular electronic structure via the on-molecule Jahn–Teller effect influence of molecular geometry and spin state. Destruction of the parent Mott–Jahn–Teller state through chemical or physical pressurization yields an unconventional Jahn–Teller metal, where quasi-localized and itinerant electron behaviours coexist. Localized features gradually disappear with lattice contraction and conventional Fermi liquid behaviour is recovered. The nature of the underlying (correlated versus weak-coupling Bardeen–Cooper–Schrieffer theory) s-wave superconducting states mirrors the unconventional/conventional metal dichotomy: the highest superconducting critical temperature occurs at the crossover between Jahn–Teller and Fermi liquid metal when the Jahn–Teller distortion melts.

This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’.
Fullerene ion chemistry: a journey of discovery and achievement
Authors: Böhme Diethard K.
Published: August 2016

An account is provided of the extraordinary features of buckminster fullerene cations and their chemistry that we discovered in our Ion Chemistry Laboratory at York University (Canada) during a ‘golden’ period of research in the early 1990s, just after C
60
powder became available. We identified new chemical ways of C
60
ionization and tracked novel chemistry of C
60

n
+

as a function of charge state (
n
=1–3) with some 50 different reagent molecules. We found that multiple charges enhance reaction rates and diversify reaction products and mechanisms. Strong electrostatic interactions with reagent molecules were seen to reduce barriers to carbon surface bonding and charge-separation reactions, while intramolecular Coulomb repulsion appeared to localize charge on the surface or the substituent and so influence higher order chemistry, including ‘spindle’, ‘star’, ‘fuzzy ball’, ‘ball-and-chain’ and dimer ion formation. We introduced the notion of ‘apparent’ gas-phase acidity with measurements of proton-transfer reactions of multiply charged fullerene cations. We also explored the attachment of atomic metal cations to C
60
and their subsequent reactions. All these findings were applied to the possible chemistry of fullerene cations in the interstellar medium with a focus on multiply charged fullerene ion formation and the intervention of fullerene cations in fullerene derivatization and molecular synthesis, with a view to their possible future detection.

This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’.
Super-atom molecular orbital excited states of fullerenes
Authors: Johansson J. Olof , Bohl Elvira , Campbell Eleanor E. B.
Published: August 2016

Super-atom molecular orbitals are orbitals that form diffuse hydrogenic excited electronic states of fullerenes with their electron density centred at the centre of the hollow carbon cage and a significant electron density inside the cage. This is a consequence of the high symmetry and hollow structure of the molecules and distinguishes them from typical low-lying molecular Rydberg states. This review summarizes the current experimental and theoretical studies related to these exotic excited electronic states with emphasis on femtosecond photoelectron spectroscopy experiments on gas-phase fullerenes.

This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’.
Fullerene and nanotube growth: new insights using first principles and molecular dynamics
Authors: Cruz-Silva Rodolfo , Araki Takumi , Hayashi Takuya , Terrones Humberto , Terrones Mauricio , Endo Morinobu
Published: August 2016

Shortly after the discovery of fullerenes, many researchers pointed out that carbon nanotubes could be considered as elongated fullerenes. However, the detailed formation mechanism for both structures has been a topic of debate for several years, and consequently it has been difficult to draw a clear connection between the two systems. While the synthesis conditions appear to be different for both fullerenes and nanotubes, here, we demonstrate that it is highly likely that, at an initial growth stage, single-walled carbon nanotubes begin to grow from a hemisphere-like fullerene cap. More importantly, by analysing the minimum-energy path, it is shown that the insertion of C
2
fragments drives the transformation of this fullerene cap into an elongated structure that leads to the formation of very short carbon nanotubes.

This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’.
Many shades of green: the dynamic tropical forest–savannah transition zones
Authors: Oliveras Immaculada , Malhi Yadvinder
Published: August 2016

The forest–savannah transition is the most widespread ecotone in tropical areas, separating two of the most productive terrestrial ecosystems. Here, we review current understanding of the factors that shape this transition, and how it may change under various drivers of local or global change. At broadest scales, the location of the transition is shaped by water availability, mediated strongly at local scales by fire regimes, herbivory pressure and spatial variation in soil properties. The frequently dynamic nature of this transition suggests that forest and savannah can exist as alternative stable states, maintained and separated by fire–grass feedbacks and tree shade–fire suppression feedback. However, this theory is still contested and the relative contributions of the main biotic and abiotic drivers and their interactions are yet not fully understood. These drivers interplay with a wide range of ecological processes and attributes at the global, continental, regional and local scales. The evolutionary history of the biotic and abiotic drivers and processes plays an important role in the current distributions of these transitions as well as in their species composition and ecosystem functioning. This ecotone can be sensitive to shifts in climate and other driving factors, but is also potentially stabilized by negative feedback processes. There is abundant evidence that these transitions are shifting under contemporary global and local changes, but the direction of shift varies according to region. However, it still remains uncertain how these transitions will respond to rapid and multi-faceted ongoing current changes, and how increasing human influence will interact with these shifts.

This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.
Woody encroachment over 70 years in South African savannahs: overgrazing, global change or extinction aftershock?
Authors: Stevens Nicola , Erasmus B. F. N. , Archibald S. , Bond W. J.
Published: August 2016

Woody encroachment in ‘open’ biomes like grasslands and savannahs is occurring globally. Both local and global drivers, including elevated CO
2
, have been implicated in these increases. The relative importance of different processes is unresolved as there are few multi-site, multi-land-use evaluations of woody plant encroachment. We measured 70 years of woody cover changes over a 1020 km
2
area covering four land uses (commercial ranching, conservation with elephants, conservation without elephants and communal rangelands) across a rainfall gradient in South African savannahs. Different directions of woody cover change would be expected for each different land use, unless a global factor is causing the increases. Woody cover change was measured between 1940 and 2010 using the aerial photo record. Detection of woody cover from each aerial photograph was automated using eCognitions' Object-based image analysis (OBIA). Woody cover doubled in all land uses across the rainfall gradient, except in conservation areas with elephants in low-rainfall savannahs. Woody cover in 2010 in low-rainfall savannahs frequently exceeded the maximum woody cover threshold predicted for African savannahs. The results indicate that a global factor, of which elevated CO
2
is the likely candidate, may be driving encroachment. Elephants in low-rainfall savannahs prevent encroachment and localized megafaunal extinction is a probable additional cause of encroachment.

This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.
Human Clostridium difficile infection caused by a livestock-associated PCR ribotype 237 strain in Western Australia
Authors: Mc Govern Alan M. , Foster Niki F. , Pereira Lynette A. , Knight Daniel R. , Elliott Briony , Chang Barbara J. , Riley Thomas V.
Published: August 2016

Introduction:

Clostridium difficile infection (CDI) is a significant gastrointestinal disease in the developed world and increasingly recognised as a zoonotic infection. In North America and Europe, the PCR ribotype (RT) 078 strain of C. difficile is commonly found in production animals and as a cause of disease in humans although proof of transmission from animals is lacking. This strain is absent in Australian livestock. We report a case of human CDI caused by a strain of C. difficile belonging to known Australian livestock-associated RT 237.

Case presentation:

A young male was admitted for multiple trauma following a motor vehicle accident and placed on piperacillin/tazobactam for pneumonia. After 4 days of treatment, he developed symptoms of CDI, which was confirmed in the laboratory. His symptoms resolved after 6 days of intravenous metronidazole. The strain of C. difficile isolated was identified as RT 237, an unusual RT previously found in with several Western Australia piggeries.

Conclusion:

This case of CDI caused by an unusual livestock-associated C. difficile RT 237 supports the hypothesis of zoonotic transmission. The case highlights the potential of livestock to act as reservoir for C. difficile and the need for continued surveillance of CDI in both human and animal populations.
New figuring model based on surface slope profile for grazing-incidence reflective optics
Authors: Zhou Lin , Huang Lei , Bouet Nathalie , Kaznatcheev Konstantine , Vescovi Matthew , Dai Yifan , Li Shengyi , Idir Mourad
Published: August 2016

Surface slope profile is widely used in the metrology of grazing-incidence reflective optics instead of surface height profile. Nevertheless, the theoretical and experimental model currently used in deterministic optical figuring processes is based on surface height, not on surface slope. This means that the raw slope profile data from metrology need to be converted to height profile to perform the current height-based figuring processes. The inevitable measurement noise in the raw slope data will introduce significant cumulative error in the resultant height profiles. As a consequence, this conversion will degrade the determinism of the figuring processes, and will have an impact on the ultimate surface figuring results. To overcome this problem, an innovative figuring model is proposed, which directly uses the raw slope profile data instead of the usual height data as input for the deterministic process. In this paper, first the influence of the measurement noise on the resultant height profile is analyzed, and then a new model is presented; finally a demonstration experiment is carried out using a one-dimensional ion beam figuring process to demonstrate the validity of our approach.
A putative siderophore-interacting protein from the marine bacteriumShewanella frigidimarinaNCIMB 400: cloning, expression, purification, crystallization and X-ray diffraction analysis
Authors: Trindade Inês B. , Fonseca Bruno M. , Matias Pedro M. , Louro Ricardo O. , Moe Elin
Published: August 2016

Siderophore-binding proteins (SIPs) perform a key role in iron acquisition in multiple organisms. In the genome of the marine bacteriumShewanella frigidimarinaNCIMB 400, the gene tagged as SFRI_RS12295 encodes a protein from this family. Here, the cloning, expression, purification and crystallization of this protein are reported, together with its preliminary X-ray crystallographic analysis to 1.35 Å resolution. The SIP crystals belonged to the monoclinic space groupP21, with unit-cell parametersa= 48.04,b= 78.31,c= 67.71 Å, α = 90, β = 99.94, γ = 90°, and are predicted to contain two molecules per asymmetric unit. Structure determination by molecular replacement and the use of previously determined ∼2 Å resolution SIP structures with ∼30% sequence identity as templates are ongoing.
Synthesis and crystal structure of tricarbonylchlorido{1-[(pyridin-2-ylmethylidene)amino]adamantane}rhenium(I)
Authors: Jimenez Jorge , Chakraborty Indranil , Mascharak Pradip
Published: August 2016

The title compound, [ReCl(pyAm)(CO)3], where pyAm is 1-[(pyridin-2-ylmethylidene)amino]adamantane (C16H20N2), was synthesized from the reaction of [ReCl(CO)5] and pyAm in an equimolar ratio. The ReI atom resides in an octahedral C3ClN2 coordination sphere. The Re—C bond trans to the chloride ligand is noticeably longer compared to the other two Re—C distances. Weak C—H...Cl hydrogen-bonding interactions consoldiate the packing of the molecules. In this design, the pyAm ligand was employed due to its well-known pharmacokinetic properties.
(−)-Sparteinium tetrachloridozincate monohydrate
Authors: Bernès Sylvain , Gutiérrez René , Hernández-Téllez Guadalupe , Moreno Gloria E.
Published: August 2016

The title ionic compound, (C15H28N2)[ZnCl4]·H2O, is isostructural with the CuIIanalogue published previously [Leeet al.(2004).Bull. Korean Chem. Soc.25, 823–828; Jasiewiczet al.(2006).J. Mol. Struct.794, 311–319]. The [ZnCl4]2−anion is, however, much more close to the tetrahedral conformation than the [CuCl4]2−ion. In the tetrachloridozincate anion, the Cl—Zn—Cl angles are in the range 103.57 (3)–116.81 (3)°.
Bis[dihydrobis(pyrazol-1-yl-κN2)borato]bis(methanol-κO)iron(II)
Authors: Ossinger Sascha , Näther Christian , Tuczek Felix
Published: August 2016

The structure determination was undertaken as part of a project on the synthesis of new spin-crossover compounds based on octahedral FeIIbis(pyrazolyl)borate complexes. The asymmetric unit of the title compound, [Fe(H2B(pz)2)2(CH3OH)2] [H2B(pz)2= dihydrobis(pyrazol-1-yl)borate, C6H8BN4], consists of one FeIIcation that is located on a centre of inversion, as well as one methanol molecule and one H2B(pz)2dianion that occupy general positions. In the crystal, the FeIIcations are coordinated by two methanol molecules and four N atoms of two H2B(pz)2anions within a slightly distorted octahedron. Bond lengths and angles between the FeIIatom and the H2B(pz)2anion are comparable to those in related FeIIcomplexes.
Collision avoidance for mobile robots based on artificial potential field and obstacle envelope modelling
Authors: Wu Zhenyu , Hu Guang , Feng Lin , Wu Jiping , Liu Shenglan
Published: August 2016

Purpose

This paper aims to investigate the collision avoidance problem for a mobile robot by constructing an artificial potential field (APF) based on geometrically modelling the obstacles with a new method named the obstacle envelope modelling (OEM).

Design/methodology/approach

The obstacles of arbitrary shapes are enveloped in OEM using the primitive, which is an ellipse in a two-dimensional plane or an ellipsoid in a three-dimensional space. As the surface details of obstacles are neglected elegantly in OEM, the workspace of a mobile robot is made simpler so as to increase the capability of APF in a clustered environment.

Findings

Further, a dipole is applied to the construction of APF produced by each obstacle, among which the positive pole pushes the robot away and the negative pole pulls the robot close.

Originality/value

As a whole, the dipole leads the robot to make a derivation around the obstacle smoothly, which greatly reduces the local minima and trajectory oscillations. Computer simulations are conducted to demonstrate the effectiveness of the proposed approach.
A method for common design structure discovery in assembly models using information from multiple sources
Authors: Zhang Jie , Zuo Mi , Wang Pan , Yu Jian-feng , Li Yuan
Published: August 2016

Purpose

Design is a time-consuming process for mechanical production. Some design structures frequently occur in different products and can be shared by multiple assembly models. Thus, identifying these structures and adding them to a design knowledge library significantly speed up the design process. Most studies addressing this issue have traditionally focused on part models and have not extended to assembly models. This paper aims to find a method for common design structure discovery in assembly models.

Design/methodology/approach

Computer-aided design models have a great deal of valuable information defined by different designers in the design stages, especially the assembly models, which are actually carriers of information from multiple sources. In this paper, an approach for discovering a common design structure in assembly models is proposed by comparing information from multiple sources. Assembly models are first represented as attribute connection graphs (ACGs), in which we mainly consider topological information and various attributes of parts and connections. Then, we apply a K-means clustering method based on a similarity analysis of different attributes to classify the parts and connections and transform ACGs of assemblies into type code graphs (TCGs). After this, a discovery algorithm that improves upon fast frequent subgraph mining is used to identify common design structures in assemblies.

Findings

A new method was developed for discovering common design structures in assembly models, considering the similarity of information from multiple sources and allowing some differences in the details to keep both commonalities and individualities of common design structures.

Practical implications

Experiments show that the proposed method is efficient and can produce a reasonable result.

Originality/value

This discovery method helps designers find common design structures from different assembly models and shorten the design cycle. It is an effective approach to build a knowledge library for product design that can shorten the design cycle.
Development and testing of an assessment model for social enterprises
Authors: Lobato-Calleros Maria Odette , Fabila Rodriguez Karla , Carrera-Lobato Paulina , Carrera-Lobato Rodrigo
Published: August 2016

Purpose

– The trend toward the indiscriminate use of natural resources and social decay has widened the gap between social classes, rich and poor, leaving the poorest unprotected. This situation, with the current financial crisis has also led to the creation of social organizations by the people in the highest levels of marginalization, through which they sell products manufactured by themselves and support enhance the economy and enhance a better quality of life for themselves. The paper aims to discuss these issues.

Design/methodology/approach

– A major development for growth of these organizations is the existence of responsible consumerism. Thanks to the technological advancements and the mass distribution of information, and the supply chain, the world population is beginning to get aware and becoming concerned by the effects of the hyper-consumption culture currently prevailing.

Findings

– The existing models of national indices based on consumer opinion and satisfaction merely include the characteristics of the products and services offered, but do not include variables that aid in determining their impact on a social enterprise. This research aims to fill that gap.

Originality/value

– The paper shares the results of a qualitative and quantitative survey performed during the first half of 2014 using a model of structural equations developed to test new hypotheses that include a variable which has been called “social responsibility.”
Comparison of diffused layer prepared using liquid dopant solutions and pastes for solar cell with screen printed electrodes
Authors: Drabczyk Kazimierz , Wróbel Edyta , Kulesza-Matlak Grazyna , Filipowski Wojciech , Waczynski Krzysztof , Lipinski Marek
Published: August 2016

Purpose

The purpose of this study is comparison of the diffusion processes performed using the commercial available dopant paste made by Filmtronics and the original prepared liquid dopant solution. To decrease prices of industrially produced silicon-based solar cells, the new low-cost production processes are necessary. The main components of most popular silicon solar cells are with diffused emitter layer, passivation, anti-reflective layers and metal electrodes. This type of cells is prepared usually using phosphorus oxychloride diffusion source and metal pastes for screen printing. The diffusion process in diffusion furnace with quartz tube is slow, complicated and requires expensive equipment. The alternative for this technology is very fast in-line processing using the belt furnaces as an equipment. This approach requires different dopant sources.

Design/methodology/approach

In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution. The investigation was focused on dopant sources fabrication and diffusion processes. The doping solution was made in two stages. In the first stage, a base solution (without dopants) was made: dropwise deionized (DI) water and ethyl alcohol were added to a solution consisting of tetraethoxysilane (TEOS) and 99.8 per cent ethyl alcohol. Next, to the base solution, orthophosphoric acid dissolved in ethyl alcohol was added.

Findings

Diffused emitter layers with sheet resistance around 60 Ω/sq were produced on solar grade monocrystalline silicon wafers using two types of dopant sources.

Originality/value

In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution.
Measuring and understanding the engagement of Bangladeshi SMEs with sustainable and socially responsible business practices: an ISO 26000 perspective
Authors: Hasan Md Nazmul
Published: August 2016

Purpose

Drawing on the “ISO 26000: 2010 – Guidance on social responsibility” handbook, this paper aims to investigate the extent to which Bangladeshi small- and medium-sized manufacturing enterprises (SMEs) are incorporating social responsibility (SR)/sustainability into their regular business activities. It is also aimed at providing insights into how Bangladeshi SME owner-managers perceive the concept of SR, and exploring the key drivers of and barriers to socially responsible and sustainable business practices.

Design/methodology/approach

A mixed-method research was carried out in two sequential phases. During the first phase, 110 printed questionnaires (59 of which were eventually used) were distributed among the owner-managers of the selected SMEs. The second phase involved seven in-depth semi-structured interviews.

Findings

The findings reconfirm the existence of the so called “attitude-behaviour” gap. The barriers that hinder the sustainable engagement of SMEs include corruption, a weak regulatory environment, inefficient or ill-suited government and external support and a lack of awareness of the environmental aspects of SR. In addition, this research reveals that Bangladeshi manufacturing SMEs do, to a certain degree, implement SR; only those few issues that suit the owner-managers’ personal motives are addressed, while many others (e.g. environmental issues) are neglected. Finally, it has been found that the business type and size, and the owner-managers’ educational attainments have no significant influence on the degree of adoption of socially responsible business practices by Bangladeshi manufacturing SMEs.

Originality/value

This paper develops a tool suited to meaningfully assess the socially responsible and sustainable business activities of SMEs. By using the four key elements identified in ISO 26000, namely, labour practices, the environment, consumer issues and community involvement and development, and by using an innovative and effective technique, a sustainability score and implementation level were calculated quantitatively for the selected SMEs. The tool developed here can be used to study the sustainability related issues faced by SMEs based in other low-income developing countries.