bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relativistic collisionless shocks formation in pair plasmas
Authors: BRET ANTOINE , STOCKEM A. , FIUZA F. , RUYER C. , GREMILLET L. , NARAYAN R. , SILVA L. O. 
Published: April 2013

AbstractCollisionless shocks are ubiquitous in astrophysics and in the laboratory. Recent numerical simulations and experiments have shown how these can arise from the encounter of two collisionless plasma shells. When the shells interpenetrate, the overlapping region turns unstable, triggering the shock formation. As a first step toward a microscopic understanding of the process, we here analyze in detail the initial instability phase. On the one hand, 2D relativistic PIC simulations are performed where two unmagnetized, symmetric, and initially cold pair plasmas collide. On the other hand, the instabilities at work are analyzed, as well as the field at saturation and the seed field which gets amplified. For mildly relativistic motions and onward, Weibel modes with ω=0+iδ govern the linear phase. We derive an expression for the duration of the linear phase in reasonable agreement with the simulations.
Another look at divine hiddenness
Authors: CUNEO TERENCE 
Published: April 2013

AbstractIn his fine book The Wisdom to Doubt, J. L. Schellenberg builds a case for religious scepticism by advancing a version of the Hiddenness Argument. This argument rests on the claim that God could not love, in an admirable way, those who seek God while also remaining hidden from them. In this article, I distinguish two arguments for this claim. Neither argument succeeds, I contend, as each rests on an unsatisfactory understanding of the nature of admirable love, whether human or divine.
Limited evidence for allelopathic effects of giant hogweed on germination of native herbs
Authors: Wille Wibke , Thiele Jan , Walker Emer A. , Kollmann Johannes 
Published: April 2013

AbstractInvasive alien plants often occur in monospecific stands with high density in the invaded range. Production of bioactive secondary metabolites in such stands could have allelopathic effects on germination of native species. We tested this component of the novel weapon hypothesis for Heracleum mantegazzianum, a prominent invader in Europe, using seeds of 11 native herbs exposed to soil or soil extracts from invaded stands, moist seeds or seed extracts of H. mantegazzianum. There was no effect of the various treatments on germination of most species, while germination was reduced in Urtica dioica on invaded soil, in Poa trivialis with H. mantegazzianum seed extract, and negative effects of the essential oil bergapten were found in three species. In P. trivialis the results of the seed extract were not supported by the experiment with added seeds of the invasive plant. Thus, there is limited evidence for allelopathic effects of the invasive H. mantegazzianum on germination of co-occurring native herbs.
Increased axonal bouton dynamics in the aging mouse cortex
Authors: Grillo Federico W. , Song Sen , Teles-Grilo Ruivo Leonor M. , Huang Lieven , Gao Ge , Knott Graham W. , Maco Bohumil , Ferretti Valentina , Thompson Dawn , Little Graham E. , De Paola Vincenzo 
Published: March 2013

Significance
Synaptic plasticity is considered an essential process for the formation and maintenance of memory. It had been assumed for decades that cognitive deficits within the aging brain result from reduced synaptic density and plasticity. By imaging axonal arbors and boutons in the aged brain, we surprisingly find the opposite, i.e., dramatically increased rates of synapse formation, elimination, and destabilization in specific cortical circuits. This observation suggests that learning and memory deficits in the aged brain may arise not through an inability to form new synapses but rather through decreased synaptic tenacity.
Social Connection and Seeing Human
Authors: Waytz Adam 
Published: April 2013

Abstract
Given that the motivation to affiliate with others is one of the most fundamental and important motivations, humans have developed a variety of strategies to cope with lack of affiliation following experiences of social exclusion. One strategy is anthropomorphism, whereby people create social connection by treating nonhumans as human-like agents capable of social support. This chapter reviews evidence that social exclusion increases the tendencies to anthropomorphize and to seek social connection with nonhumans. It also addresses three questions that follow from people’s tendency to anthropomorphize as a means to attain social connection: (1) Is social connection with nonhumans effective? (2) Does connection with nonhumans diminish interest in connections with humans? (3) Could increases in social connection in fact increase dehumanization of other people? In attempting to answer these questions, this chapter provides avenues for future research on the relationship between social connection and seeing human.
Interlocking Feedback Loops Govern the Dynamic Behavior of the Floral Transition inArabidopsis
Authors: Jaeger Katja E. , Pullen Nick , Lamzin Sergey , Morris Richard J. , Wigge Philip A. 
Published: March 2013

AbstractDuring flowering, primordia on the flanks of the shoot apical meristem are specified to form flowers instead of leaves. Like many plants, Arabidopsis thaliana integrates environmental and endogenous signals to control the timing of reproduction. To study the underlying regulatory logic of the floral transition, we used a combination of modeling and experiments to define a core gene regulatory network. We show that FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) act through FD and FD PARALOG to regulate the transition. The major floral meristem identity gene LEAFY (LFY) directly activates FD, creating a positive feedback loop. This network predicts flowering behavior for different genotypes and displays key properties of the floral transition, such as signal integration and irreversibility. Furthermore, modeling suggests that the control of TFL1 is important to flexibly counterbalance incoming FT signals, allowing a pool of undifferentiated cells to be maintained despite strong differentiation signals in nearby cells. This regulatory system requires TFL1 expression to rise in proportion to the strength of the floral inductive signal. In this network, low initial levels of LFY or TFL1 expression are sufficient to tip the system into either a stable flowering or vegetative state upon floral induction.
Do intravenous and subcutaneous angiotensin II increase blood pressure by different mechanisms?
Authors: Campbell Duncan J 
Published: March 2013

Summary

Angiotensin (Ang) II plays a key role in blood pressure regulation. Mechanisms of the pressor effect of chronic intravenous AngII administration include vasoconstriction, stimulation of the sympathetic nervous system and aldosterone production, as well as direct effects on renal excretion of sodium and water.

Chronic AngII administration by subcutaneous minipump at doses higher than required to increase blood pressure by the intravenous route has identified additional pressor mechanisms, including the immune system, cytokines and matrix metalloproteinases. However, pressor doses of subcutaneous AngII may exceed the angiotensinogen synthesis rate and produce inflammation, fibrosis and necrosis of skin overlying the minipump.

Evidence that chronic subcutaneous and intravenous AngII increase blood pressure by different mechanisms includes the prevention of the pressor effects of subcutaneous, but not intravenous, AngII by angiotensin‐converting enzyme inhibition. Furthermore, low doses of subcutaneous AngII reduce blood pressure of female, but not male, rodents and higher doses are less pressor in females than in males, whereas intravenous AngII is equally pressor in males and females.

Pressor doses of chronic subcutaneous AngII produce greater weight loss, anorexia and reduced kidney weight and cause greater vascular, cardiac and renal pathology than equally pressor doses of chronic intravenous AngII.

The different effects of chronic intravenous and subcutaneous AngII suggest that these two models of hypertension give different information and may differ in their relevance to blood pressure regulation in physiological and pathological states such as hypertension in humans.
Presence of Oxytocin, Vasopressin and Atrial Natriuretic Peptide and Their Modification in Rat Hypothalamic Paraventricular Nucleus During Resistance Training
Authors: Farina E. V. , Cappello F. , Lipari L. , Valentino A. , Di Felice V. , Valentino B. 
Published: April 2013

SummaryMany studies have demonstrated the physiological effects of oxytocin (OT), atrial natriuretic peptide (ANP) and vasopressin (VP) in the homoeostasis of body fluids during physical exercise. However, a little information is available about the related immunohistochemical changes in hypothalamic magnocellular neurosecretory system during and after the training. The aim of the present work was to study the immunohistochemical changes in OT, ANP and VP levels in the hypothalamic paraventricular nucleus during and after resistance exercise protocol. Three groups of Wistar rats were trained by a rung ladder protocol for 15, 30 and 45 days, respectively; a fourth group was left to rest for 15 days after the training. Finally, four sedentary groups were used as controls. The results show that resistance training induces a significant reduction in the percentage of OT‐positive neurons, compared with sedentary controls. In contrast, this protocol did not induce any change in VP levels, and ANP levels did not change significantly. However, VP increased after the resting period of 15 days. Our work shows that neurons of the paraventricular nucleus are involved in body fluid homoeostasis during and after resistance exercise. The functional significance of these changes in OT and VP levels, during and after the protocol, needs to be further investigated.
Soil biota of different size classes change the impact of soil compaction on a plant community
Authors: Beck Mara E. , Wurst Susanne 
Published: March 2013

AbstractQuestionDoes a reduction in size class of soil biota aggravate the impacts of soil compaction on plant communities?LocationControlled mesocosm study with a European ruderal plant community exposed to soil compaction and soil biota communities of different size classes.MethodsWe evaluated the individual and combined effects of soil compaction and soil biota communities of different size classes (<2000, <212, <20 μm, natural control) on the structure and productivity of a ruderal plant community, and the establishment of a neophyte (Lupinus polyphyllus) in a full‐factorial mesocosm study.ResultsSoil compaction reduced the productivity of the plant community, but the negative effect decreased in magnitude as the size class of the soil biota community was reduced. Consistently, shoot growth of the dominant grasses was most reduced by soil compaction when bigger soil biota were present; the shoot growth of forbs showed an opposite pattern. In contrast, legumes seem to profit from soil compaction independent of the size class of the soil biota community, and were detrimentally affected only in the natural control soil. Establishment of the neophyte L. polyphyllus was best under natural soil conditions and was not affected by soil compaction.ConclusionsA reduction in soil biota size due to intensified management may change the impacts of soil compaction on plant communities. The results indicate that soil compaction has the most detrimental effect on primary productivity in soil communities where a range of size classes of soil biota is present and the functional complexity of the soil biota community is therefore high.
A randomized and controlled clinical trial of two different compositions of deproteinized bovine bone and autogenous bone used for lateral ridge augmentation
Authors: Mordenfeld Arne , Johansson Carina B. , Albrektsson Tomas , Hallman Mats 
Published: April 2013

AbstractObjectiveThe aim of the study was to radiologically and histologically evaluate the graft healing and volumetric changes after lateral augmentation with two different compositions of deproteinized bovine bone (DPBB) and autogenous bone (AB).Material and methodsThirteen patients with a mean age of 59.6 ± 12.1 years (six men and seven women) were included in this randomized and controlled trial, designed as a split‐mouth study. Ten edentulous and four partially edentulous jaws with an alveolar ridge width of ≤4 mm were laterally augmented with a graft composition of 60 : 40 (DPBB/AB) on one side and 90 : 10 (DPBB/AB) on the contralateral side. Cone beam computed tomography (CB/CT) was obtained immediately postoperatively and after a healing period of 7.5 months. Width changes were measured on CB/CT scans. After a mean healing period of 8.1 months (range, 7.9–8.3), biopsies were retrieved perpendicular to the crest from each graft by means of a trephine bur. Histomorphometry was performed, and the following variables were recorded: Ingrowth of new bone (percentage of total graft width), percentage of DPBB, bone and soft tissue, and percentage of DPBB particles in contact with bone.ResultsThe mean gained width of the alveolar crest after 7.5 months was significantly more for the 60 : 40 mixture compared with the 90 : 10 mixture, 3.5 (±1.3) mm and 2.9 (±1.3) mm, respectively. There was a significant difference in graft width reduction between 60 : 40 and 90 : 10 after 7.5 months, 37 (±19.9)% and 46.9 (±23.5)%, respectively. New bone ingrowth had occurred in 82.1 (±23.3)% and 82.3 (±26.6)% of the graft, respectively. There were no statistical differences between fractions of different tissues between the 90 : 10 and 60 : 40 compositions. However, there were significantly more soft tissue and less new bone formation closer to the periosteum compared with the graft portion closer to the residual bone in both 60 : 40 and 90 : 10 compositions.ConclusionsThere was significantly less graft width reduction with a mixture of 60 : 40 (DPBB/AB) compared with a mixture of 90 : 10 composition, but the results from the histomorphometry showed no statistical differences comparing the groups.
Histological, radiological and histomorphometric evaluation of immediate vs. non‐immediate loading of a zirconia implant with surface treatment in a dog model
Authors: Calvo‐Guirado Jose L. , Aguilar‐Salvatierra Antonio , Gomez‐Moreno Gerardo , Guardia Javier , Delgado‐Ruiz Rafael A. , Mate‐Sanchez de Val Jose Eduardo 
Published: April 2013

AbstractObjectiveThe aim of this study was to assess the performance of zirconia implants under immediate loading compared with delayed loading in dogs over 30–90 days.Materials and MethodsTooth extractions were made for the subsequent placement of dental implants at premolars P2, P3, P4 and molars M1 bilaterally in the dog mandible. Forty eight zirconia implants, 4 mm in diameter and 10 mm in length, were inserted, whose neck and body surfaces had been treated with femtosecond laser texturing; 24 implants were loaded immediately and 24 remained unloaded during the osseointegration period. Final radiographs were taken recording stability values before sacrifice at 30 or 90 days when sample removal for histological and histomorphometric analysis was performed. Bone‐to‐implant contact, crestal bone loss and implant stability were evaluated at these two study times.ResultsBone‐to‐implant contact values after 30 days were 38.9% for immediately loaded implants and 32% for non‐loaded implants. After 90 days, values increased to 65% for immediately loaded and 57.6% for non‐loaded implants. After 30 days, there was more crestal bone lost in the non‐loaded group (0.58 ± 0.28 mm) compared with the immediately loaded group (0.5 ± 0.3 mm). After 90 days, there was improved stability in both groups, but was lower in the immediately loaded group (0.5 ± 0.23 mm) compared with the non‐loaded group (0.56 ± 0.28 mm). Initial implant stability values were −3.5 PTV at the moment of implant placement. Stability values after the first 30 days were −4 for immediately loaded implants and −3 for non‐loaded. At 90 days, non‐loaded implants showed −4.9, whereas immediately loaded showed −7.1.ConclusionsFor the different parameters studied, zirconia implants treated with femtosecond laser and subjected to immediate loading showed better results compared with non‐loaded implants in terms of BIC, crestal bone loss and implant stability.
The effect of hydrofluoric acid treatment of titanium and titanium dioxide surface on primary human osteoblasts
Authors: Pham Maria H. , Landin Maria A. , Tiainen Hanna , Reseland Janne E. , Ellingsen Jan Eirik , Haugen Håvard J. 
Published: April 2013

AbstractObjectiveThe aim of the study was to investigate solely the effect of fluoride on the surface chemistry of polycrystalline ceramic titanium dioxide (TiO2) and metallic titanium (Ti) and its effect on proliferation and differentiation of primary human osteoblasts (NHO).Materials and methodsThe NHO cells were exposed to fluoride‐modified and unmodified samples for 1, 3, 7, 14 and 21 days. The fluoride effect on the mRNA expression was quantified and measured. The secretion of cytokines and interleukins in the cell culture medium was measured by Luminex, gene expression by RT‐PCR, and compared with untreated controls. The effect on cell growth after 1 and 3 days in culture was measured using [3H]‐thymidine incorporation. Fluoride release was measured using an ion‐selective electrode. The surfaces were examined by X‐ray photoelectron spectroscopy and profilometry.ResultsThe fluoride release study detected that fluoride content easily washed off in TiO2 coins when compared with Ti coins. No increase in cell proliferation was found among fluoride‐modified TiO2 surfaces compared with controls, except for washed Ti coins with fluoride modification. The cell differentiation with regard to gene expression showed no significant differences in both fluoride‐modified and unmodified samples and less effect on protein release for all groups.ConclusionsThe fluoride from hydrofluoric acid treatment on Ti and TiO2 surfaces gave no specific effect on primary human osteoblast cells. The study indicates that the released fluoride is not the unique factor for the bioactivity of Ti and TiO2 surfaces.
Antibiotic resistance in human peri‐implantitis microbiota
Authors: Rams Thomas E. , Degener John E. , van Winkelhoff Arie J. 
Published: April 2013

AbstractObjectivesBecause antimicrobial therapy is often employed in the treatment of infectious dental implant complications, this study determined the occurrence of in vitro antibiotic resistance among putative peri‐implantitis bacterial pathogens.MethodsSubmucosal biofilm specimens were cultured from 160 dental implants with peri‐implantitis in 120 adults, with isolated putative pathogens identified to species level, and tested in vitro for susceptibility to 4 mg/l of doxycycline, 8 mg/l of amoxicillin, 16 mg/l of metronidazole, and 4 mg/l of clindamycin. Findings for amoxicillin and metronidazole were combined post‐hoc to identify peri‐implantitis species resistant to both antibiotics. Gram‐negative enteric rods/pseudomonads were subjected to ciprofloxacin disk diffusion testing.ResultsOne or more cultivable submucosal bacterial pathogens, most often Prevotella intermedia/nigrescens or Streptococcus constellatus, were resistant in vitro to clindamycin, amoxicillin, doxycycline, or metronidazole in 46.7%, 39.2%, 25%, and 21.7% of the peri‐implantitis subjects, respectively. Only 6.7% subjects revealed submucosal test species resistant in vitro to both amoxicillin and metronidazole, which were either S. constellatus (one subject) or ciprofloxacin‐susceptible strains of gram‐negative enteric rods/pseudomonads (seven subjects). Overall, 71.7% of the 120 peri‐implantitis subjects exhibited submucosal bacterial pathogens resistant in vitro to one or more of the tested antibiotics.ConclusionsPeri‐implantitis patients frequently yielded submucosal bacterial pathogens resistant in vitro to individual therapeutic concentrations of clindamycin, amoxicillin, doxycycline, or metronidazole, but only rarely to both amoxicillin and metronidazole. Due to the wide variation in observed drug resistance patterns, antibiotic susceptibility testing of cultivable submucosal bacterial pathogens may aid in the selection of antimicrobial therapy for peri‐implantitis patients.
Ligation of the intersphincteric fistula tract in the management of anal fistula. A systematic review
Authors: Yassin N. A. , Hammond T. M. , Lunniss P. J. , Phillips R. K. S. 
Published: March 2013

AbstractAimOver the last 5 years, the ligation of the intersphincteric fistula tract (LIFT) procedure has become increasingly popular as a sphincter‐preserving technique for the treatment of anal fistula. The aim of this article was to review the published literature on the LIFT procedure.MethodThe Cochrane database and EMBASE were searched from January 1980 to November 2012, and PubMed from January 1966 to November 2012. All peer‐reviewed studies that investigated the LIFT procedure for the treatment of anal fistula were eligible for inclusion. Technical notes, commentaries, letters and meeting abstracts were excluded. The primary outcome measured was the overall fistula closure rate in relation to the length of follow‐up.ResultsTwenty‐nine articles were originally identified using the search criteria. Thirteen were finally included for analysis. Sample sizes ranged from 18 to 93 patients, with a pooled total of 498. Most fistulae, 494 (99%), were of cryptoglandular aetiology, of which 470 (94%) were transsphincteric. Overall success rates ranged from 40 to 95%, with a pooled success of 71% (352 of 495 patients; 3 of 498 were lost to follow‐up). Follow‐up ranged from 1 to 55 months, with a reported mean or median of 4 to 19.5 months. One hundred and eighty‐three patients were formally assessed for continence, out of whom 11 (6%) had a minor disturbance.ConclusionOverall the systematic review shows that the LIFT procedure appears to be an effective sphincter‐conserving approach for the treatment of transsphincteric anal fistula with a pooled healing rate of 71% over a mean or median follow‐up period ranging from 4 to 19.5 months.
Comprehensive and Rapid Assessment of Carotid Plaques in Acute Stroke Using a New Single Sweep Method for Three‐Dimensional Carotid Ultrasound
Authors: Kalashyan Harapet , Saqqur Maher , Shuaib Ashfaq , Romanchuk Helen , Nanda Navin C. , Becher Harald 
Published: April 2013

We describe a 68‐year‐old man with acute stroke in whom the newly developed single sweep method for three‐dimensional (3D) carotid ultrasound provided a rapid and comprehensive assessment of atherosclerotic plaque burden in the internal carotid artery. The two‐dimensional duplex carotid scan diagnosed 50–69% stenosis, and with the three‐dimensional method, the markedly hypoechogenic plaque (total volume 1.42 mL) was shown to occupy 77% of the total arterial volume (1.84 mL), consistent with severe lesion. The ultrasound findings were confirmed by computed tomographic angiography and subsequent carotid endarterectomy. The new single sweep 3D carotid ultrasound has the potential to become a valuable clinical tool in the assessment of stroke patients.