bluuebunny/crossref_metadata_2025 huggingface dataset:
The Pathogen Candida albicans Hijacks Pyroptosis for Escape from Macrophages
Authors: Uwamahoro Nathalie , Verma-Gaur Jiyoti , Shen Hsin-Hui , Qu Yue , Lewis Rowena , Lu Jingxiong , Bambery Keith , Masters Seth L. , Vince James E. , Naderer Thomas , Traven Ana
Published: March 2014

The fungal pathogen
Candida albicans
causes macrophage death and escapes, but the molecular mechanisms remained unknown. Here we used live-cell imaging to monitor the interaction of
C. albicans
with macrophages and show that
C. albicans
kills macrophages in two temporally and mechanistically distinct phases. Early upon phagocytosis,
C. albicans
triggers pyroptosis, a proinflammatory macrophage death. Pyroptosis is controlled by the developmental yeast-to-hypha transition of
Candida
. When pyroptosis is inactivated, wild-type
C. albicans
hyphae cause significantly less macrophage killing for up to 8 h postphagocytosis. After the first 8 h, a second macrophage-killing phase is initiated. This second phase depends on robust hyphal formation but is mechanistically distinct from pyroptosis. The transcriptional regulator Mediator is necessary for morphogenesis of
C. albicans
in macrophages and the establishment of the wild-type surface architecture of hyphae that together mediate activation of macrophage cell death. Our data suggest that the defects of the Mediator mutants in causing macrophage death are caused, at least in part, by reduced activation of pyroptosis. A Mediator mutant that forms hyphae of apparently wild-type morphology but is defective in triggering early macrophage death shows a breakdown of cell surface architecture and reduced exposed 1,3 β-glucan in hyphae. Our report shows how
Candida
uses host and pathogen pathways for macrophage killing. The current model of mechanical piercing of macrophages by
C. albicans
hyphae should be revised to include activation of pyroptosis by hyphae as an important mechanism mediating macrophage cell death upon
C. albicans
infection.

IMPORTANCE
Upon phagocytosis by macrophages,
Candida albicans
can transition to the hyphal form, which causes macrophage death and enables fungal escape. The current model is that the highly polarized growth of hyphae results in macrophage piercing. This model is challenged by recent reports of
C. albicans
mutants that form hyphae of wild-type morphology but are defective in killing macrophages. We show that
C. albicans
causes macrophage cell death by at least two mechanisms. Phase 1 killing (first 6 to 8 h) depends on the activation of the pyroptotic programmed host cell death by fungal hyphae. Phase 2 (up to 24 h) is rapid and depends on robust hyphal formation but is independent of pyroptosis. Our data provide a new model for how the interplay between fungal morphogenesis and activation of a host cell death pathway mediates macrophage killing by
C. albicans
hyphae.
Coupling Between Protein Level Selection and Codon Usage Optimization in the Evolution of Bacteria and Archaea
Authors: Ran Wenqi , Kristensen David M. , Koonin Eugene V.
Published: March 2014

The relationship between the selection affecting codon usage and selection on protein sequences of orthologous genes in diverse groups of bacteria and archaea was examined by using the Alignable Tight Genome Clusters database of prokaryote genomes. The codon usage bias is generally low, with 57.5% of the gene-specific optimal codon frequencies (
F

opt

) being below 0.55. This apparent weak selection on codon usage contrasts with the strong purifying selection on amino acid sequences, with 65.8% of the gene-specific d
N
/d
S
ratios being below 0.1. For most of the genomes compared, a limited but statistically significant negative correlation between
F

opt

and d
N
/d
S
was observed, which is indicative of a link between selection on protein sequence and selection on codon usage. The strength of the coupling between the protein level selection and codon usage bias showed a strong positive correlation with the genomic GC content. Combined with previous observations on the selection for GC-rich codons in bacteria and archaea with GC-rich genomes, these findings suggest that selection for translational fine-tuning could be an important factor in microbial evolution that drives the evolution of genome GC content away from mutational equilibrium. This type of selection is particularly pronounced in slowly evolving, “high-status” genes. A significantly stronger link between the two aspects of selection is observed in free-living bacteria than in parasitic bacteria and in genes encoding metabolic enzymes and transporters than in informational genes. These differences might reflect the special importance of translational fine-tuning for the adaptability of gene expression to environmental changes. The results of this work establish the coupling between protein level selection and selection for translational optimization as a distinct and potentially important factor in microbial evolution.

IMPORTANCE
Selection affects the evolution of microbial genomes at many levels, including both the structure of proteins and the regulation of their production. Here we demonstrate the coupling between the selection on protein sequences and the optimization of codon usage in a broad range of bacteria and archaea. The strength of this coupling varies over a wide range and strongly and positively correlates with the genomic GC content. The cause(s) of the evolution of high GC content is a long-standing open question, given the universal mutational bias toward AT. We propose that optimization of codon usage could be one of the key factors that determine the evolution of GC-rich genomes. This work establishes the coupling between selection at the level of protein sequence and at the level of codon choice optimization as a distinct aspect of genome evolution.
Renal abscesses in childhood: report of two uncommon cases
Authors: Cancelinha Candida , Santos Lea , Ferreira Carmen , Gomes Clara
Published: March 2014

Renal abscesses are rare conditions in children, but they must be remembered in differential diagnosis of fever and abdominal pain. The authors report two paediatric cases with unusual presentation. Case 1: a 15-year-old girl was admitted following a period of fever, vomiting and left hypochondrium pain which became more localised to the left lower ribs. Blood tests suggested bacterial infection, but urinalysis and culture were negative. Renal CT scan presented features of bilateral pyelonephritis and left renal abscesses, while ultrasound remained normal until the ninth day of disease. Case 2: a 2-year-old girl, with diagnosis of β-thalassemia minor, had intermittent diffuse abdominal pain with 2 weeks of evolution. Renal ultrasonography and CT scan showed a heterogeneous mass compatible with Willms tumour. Intraoperative diagnosis was compatible with renal abscess with isolation ofProteus mirabilisin the fluid. Both responded well to long-term antibiotics and to surgical drainage (in the second case).
Helicobacter pylori-negative Russell body gastritis: does the diagnosis call for screening for plasmacytic malignancies, especially multiple myeloma?
Authors: Klair Jagpal Singh , Girotra Mohit , Kaur Aneet , Aduli Farshad
Published: March 2014

Russell body gastritis (RBG) is a rare entity with unestablished pathophysiology, endoscopic findings, clinical manifestations and treatments. Literature is scarce on this clinical entity with unclear clinical significance. Of 18 cases reported, 12 tested (+) forHelicobacter pyloriand improved with treatment, but it remains unclear whether this link is coincidental or bears some clinical significance. We describe a case of elderly woman who had a follow-up oesophagogastroduodenoscopy for chronic peptic ulcers, and biopsy showed positive immunohistochemical stains for κ and λ, indicating a polytypic population of plasma cells. Immunostaining forH pyloriwas negative. Biopsies were also (−) for gastric carcinoma, lymphoma and plasmacytoma. Considering her RGB-suggestive histology and her symptoms of bone pains and anaemia, multiple myeloma screening was considered clinically relevant. The purpose of this review was to educate clinicians and gastroenterologists about this unique entity and explore its association with multiple myeloma or other plamacytic malignancies.
The importance of genetic mutation screening to determine retransplantation following failed kidney allograft from recurrent atypical haemolytic ureamic syndrome
Authors: Chua Samantha , Wong Germaine , Lim Wai Hon
Published: March 2014

We report the case of a patient with familial atypical haemolytic uraemic syndrome (aHUS) who underwent successful retransplantation 30 months following his failed first kidney allograft from recurrent aHUS. He achieved excellent graft function (creatinine 90 μmol/L), with no evidence of disease recurrence on standard maintenance immunosuppression 9 months after his second deceased donor kidney transplantation. Genetic mutation testing was not available prior to first transplant but screening prior to retransplant identified the patient as having a newly discovered mutation, c.T3566A, within exon 23 of the complement factor H (CFH) gene. Currently, public financing and subsidisation for eculizumab, a costly but effect complement (C5) inhibitor for the treatment of aHUS is not available in Australia. The decision for retransplantation must balance between the risk of disease recurrence and greater risk of death on dialysis. The absence of a more severe CFH genotype assisted in the decision for retransplantation and suggests the importance of genetic mutation screening in order to stratify the risk of disease recurrence and graft loss versus the benefit of transplantation.
Treating neuromyelitis optica with the interleukin-6 receptor antagonist tocilizumab
Authors: Lauenstein Ann-Sophie , Stettner Mark , Kieseier Bernd C , Lensch Eckart
Published: March 2014

We present a 32-year-old female patient with fulminant neuromyelitis optica. After the initial treatment with the monoclonal antibody rituximab failed, therapy with the anti-IL-6 receptor antagonist tocilizumab was initiated. The patient experienced a clinically relevant improvement from severe tetraparesis to low-grade paresis, which is still maintained. On MRI of the spinal cord an almost complete restitution of a predescribed extensive myelopathy accompanied this clinical improvement. Meanwhile clinical stability was achieved for over 1 year without any side effects of the ongoing treatment with tocilizumab.
Filling the void: a case of sepsis following the injection of a penile bulking agent
Authors: Redmond Elaine , Forde James C , Flood Hugh D
Published: March 2014

Many cosmetic procedures are now performed by non-medical personnel. Owing to the wide coverage of aesthetic procedures by the media, patients may be less informed of the serious complications that can be seen when impure materials are injected by less-skilled practitioners. The authors present a case of sepsis following the injection of a non-medical grade penile bulking agent. Although penile augmentation is under-reported in the literature, public interest in such procedures is increasing. The growing demand for such procedures needs to be addressed by the medical community.
Necrotising fasciitis after bortezomib and dexamethasone-containing regimen in an elderly patient of Waldenström macroglobulinaemia
Authors: Morita Tomohiro , Ugai Tomotaka , Tanimoto Tetsuya , Matsue Kosei
Published: March 2014

Bortezomib and high-dose dexamethasone-containing regimens are considered to be generally tolerable with few severe bacterial infections in patients with B-cell malignancies. However, information is limited concerning the safety of the regimen in elderly patients. We report a case of a 76-year-old man with Waldenström macroglobulinaemia who suffered necrotising fasciitis without neutropenia after the combination treatment with bortezomib, high-dose dexamethasone and rituximab. Despite immediate intravenous antimicrobial therapy, he succumbed 23 h after the onset. Physicians should recognise the possibility of fatal bacterial infections related to bortezomib plus high-dose dexamethasone in elderly patients, and we believe this case warrants further investigation.
A massive retroperitoneal neuroblastoma with stenosis of the inferior vena cava in a 5-month-old boy
Authors: Li Jui-Ting , Dai Yang-Hong , Kuo Shih-Ming
Published: March 2014

Neuroblastoma is the second most common retroperitoneal tumour in children after Wilms’ tumour. When it originates in the retroperitoneum, neuroblastoma usually presents as an abdominal mass with clinical manifestations of nausea, vomiting and weight loss. Imaging studies of this tumour demonstrate a heterogeneous mass with an irregular capsule and visible calcifications. Encasement and compression of the abdominal vessels, especially the inferior vena cava, are often observed. However, stenosis of the inferior vena cava has never been reported to be associated with this tumour. Here, we present a case of a 5-month-old boy with a right retroperitoneal tumour with extensive encasement of the inferior vena cava and significant narrowing of its distal part between the venous bifurcation and the tumour capsule. To our knowledge, this is the first case of neuroblastoma with this manifestation in a child.
Legal responsibilities of physicians when making participation decisions in athletes with cardiac disorders: Do guidelines provide a solid legal footing?
Authors: Panhuyzen-Goedkoop Nicole M , Smeets Joep L R M
Published: March 2014

Safe sports participation involves protecting athletes from injury and life-threatening situations. Preparticipation cardiovascular screening (PPS) in athletes is intended to prevent exercise-related sudden cardiac death by medical management of athletes at risk, which may include disqualification from sports participation. The screening physician relies on current guidelines and expert recommendations for management and decision-making. There is concern about false-positive screening results and wrongly grounding an athlete. Similarly, there is a concern about false-negative screening results and athletes participating with potentially lethal disorders. Who is legally responsible if an athlete suddenly dies after a proper PPS resulting in low risk? Several consensus documents based on expert opinion describe only a few lines on legal responsibilities in eligibility screening and disqualification decision-making in athletes. This article discusses legal responsibilities and concerns in eligibility decision-making for physicians.
Narrowing the gap between the number of athletes who dope and the number of athletes who are caught: scientific advances that increase the efficacy of antidoping tests
Authors: Botrè Francesco , de la Torre Xavier , Donati Francesco , Mazzarino Monica
Published: March 2014

The analytical methods developed and applied by the antidoping laboratories have been continuously evolving over the past 50 years, with the aim of keeping pace with the constant evolution of doping strategies. Despite this, the number of adverse analytical tests reported worldwide by the network of the WADA-accredited laboratories still seems to underestimate the actual number of doped athletes.

We investigate the most likely causes for this gap between the likely doping rate and the detection of athletes with positive doping tests. We consider laboratory and non-laboratory reasons that contribute to this gap. More specifically, laboratory issues are focused not only on those doping practices that may still be ‘invisible’ at the time of a doping test, but also on the possible role of non-conventional masking strategies. These include (1) the intake of banned drugs by specific novel drug delivery systems and (2) the coadministration of prohibited and non-prohibited drugs, taking advantage of the capacity of the latter to affect the metabolism, and consequently the detection, of the former. Non-laboratory issues include the lack of a sufficient level of ‘intelligent testing’, with the result that, even in the cases of doped athletes, the biological samples delivered to the antidoping laboratories for analysis may not contain those target analytes whose detection (and if necessary quantification above a decision limit) constitutes an adverse analytical finding. We present proposals to improve the efficacy of the doping control policies based on the analysis of biological samples and suggest how to constantly keep up with the continuous developments of new forms of doping.
A national, cross-sectional survey of children's hospital-based safety resource centres
Authors: Kendi Sadiqa , Zonfrillo Mark R , Seaver Hill Karen , Arbogast Kristy B , Gittelman Michael A
Published: March 2014

Objective

To describe the location, staffing, clientele, safety product disbursement patterns, education provided and sustainability of safety resource centres (SRCs) in US children's hospitals.

Methods

A cross-sectional survey was distributed to children's hospital-based SRC directors. Survey categories included: funding sources, customer base, items sold, items given free of charge, education provided and directors’ needs.

Results

32/38 (84.2%) SRC sites (affiliated with 30 hospitals) completed the survey. SRCs were in many hospital locations including lobby (28.1%), family resource centres (12.5%), gift shop/retail space (18.8%), mobile units (18.8%) and patient clinics (12.5%). 19% of respondents reported that their SRC was financially self-sustainable. Sales to patients predominated (mean of 44%); however, hospital employees made up a mean of 20% (range 0–60%) of sales. 78.1% of SRCs had products for children with special healthcare needs. Documentation kept at SRC sites included items purchased (96.9%), items given free of charge (65.6%) and customer demographics (50%). 56.3% of SRCs provided formal injury prevention education classes. The SRCs’ directors’ most important needs were finances (46.9%), staffing (50%) and space (46.9%). All of the directors were ‘somewhat interested’ or ‘very interested’ in each of the following: creation of a common SRC listserv, national SRC data bank and multisite SRC research platform.

Conclusions

SRCs are located in many US children's hospitals, and can be characterised as heterogeneous in location, products sold, data kept and ability to be financially sustained. Further research is needed to determine best practices for SRCs to maximise their impact on injury prevention.
Technology-related distracted walking behaviours in Manhattan's most dangerous intersections
Authors: Basch Corey H , Ethan Danna , Rajan Sonali , Basch Charles E
Published: March 2014

Use of mobile devices has been cited as a distraction while driving, and more recently, among pedestrians crossing urban streets. In 2010, over half of New York City traffic fatalities were pedestrians. The aim of this study was to estimate the prevalence of distracted walking due to pedestrians’ use of headphones, mobile phones, or both. Data were gathered by direct observations at the 10 intersections in Manhattan with the highest frequency of pedestrian–motor vehicle collisions. More than 1 in 4 of the >3500 pedestrians observed were distracted by mobile electronic devices while crossing during the ‘walk’ (28.8%) and ‘don't walk’ (26.3%) signals. Poisson regression analyses established there was a significant difference in individuals talking on a mobile device during the ‘walk’ signal versus the ‘don't walk’ signal; however, no other significant differences in other distracted walking behaviours were observed. This study contributes to the emerging literature on distracted walking behaviour by pedestrians in busy urban areas and can help to inform pedestrian-focused safety efforts.
Mechanical properties and fibrin characteristics of endovascular coil–clot complexes: relevance to endovascular cerebral aneurysm repair paradigms
Authors: Haworth Kevin J , Weidner Christopher R , Abruzzo Todd A , Shearn Jason T , Holland Christy K
Published: March 2014

Background

Although coil embolization is known to prevent rebleeding from acutely ruptured cerebral aneurysms, the underlying biological and mechanical mechanisms have not been characterized. We sought to determine if microcoil-dependent interactions with thrombus induce structural and mechanical changes in the adjacent fibrin network. Such changes could play an important role in the prevention of aneurysm rebleeding.

Methods

The stiffness of in vitro human blood clots and coil–clot complexes implanted into aneurysm phantoms were measured immediately after formation and after retraction for 3 days using unconfined uniaxial compression assays. Scanning electron microscopy of the coil–clot complexes showed the effect of coiling on clot structure.

Results

The coil packing densities achieved were in the range of clinical practice. Bare platinum coils increased clot stiffness relative to clot alone (Young's modulus 6.9 kPa and 0.83 kPa, respectively) but did not affect fibrin structure. Hydrogel-coated coils prevented formation of a clot and had no significant effect on clot stiffness (Young's modulus 2 kPa) relative to clot alone. Clot age decreased fiber density by 0.2 fibers/µm2but not the stiffness of the bare platinum coil–clot complex.

Conclusions

The stiffness of coil–clot complexes is related to the summative stiffness of the fibrin network and associated microcoils. Hydrogel-coated coils exhibit significantly less stiffness due to the mechanical properties of the hydrogel and the inhibition of fibrin network formation by the hydrogel. These findings have important implications for the design and engineering of aneurysm occlusion devices.
BMP and activin membrane-bound inhibitor (BAMBI) inhibits the adipogenesis of porcine preadipocytes through Wnt/β-catenin signaling pathway
Authors: Mai Yin , Zhang Zhenyu , Yang Hao , Dong Peiyue , Chu Guiyan , Yang Gongshe , Sun Shiduo
Published: March 2014

The process of differentiation from preadipocytes to adipocytes contributes to adipose tissue expansion in obesity. Blocking adipogenesis may be conducive to the etiology of obesity-related diseases. BMP and activin membrane-bound inhibitor (BAMBI) is a transmembrane protein, which was identified as a target of β-catenin in colorectal and hepatocellular tumor cells. However, whether BAMBI affects adipogenesis by Wnt/β-catenin signaling remains to be explored. In this study, we distinguish BAMBI as an inhibitor of preadipocytes differentiation. We found that BAMBI was downregulated during preadipocytes differentiation. Knockdown of BAMBI increased adipogenesis and blocked Wnt/β-catenin signaling by repressing β-catenin accumulation. In BAMBI overexpression cells, lipid accumulation was reduced by promoting nuclear translocation of β-catenin. Lithium chloride (LiCl) is an activator of Wnt/β-catenin signaling, which is an inhibitor of glycogen synthetase kinase-3 (GSK-3), maintaining the stability of β-catenin in cytosolic. We showed BAMBI strengthened the anti-adipogenic effects of LiCl. In addition, the results indicated that BAMBI was upregulated by β-catenin. These observations illuminated that BAMBI inhibits adipogenesis by a feedback loop (BAMBI→β-catenin nuclear translocation→BAMBI), which forms with Wnt/β-catenin signaling.
Simulation of fully grouted rockbolts in underground roadways using FLAC2D
Authors: Ma Shuqi , Nemcik Jan , Aziz Naj
Published: March 2014

A numerical modelling approach of a mine roadway reinforced with fully encapsulated rockbolts is proposed to study the interaction between rockbolts and the rock mass. The rockbolt bond–slip relationships defined by conducting push tests of short rockbolts are implemented in the rockbolt elements used in the two-dimensional Fast Lagrangian Analysis of Continua (FLAC2D) model for precise simulation of the rockbolt behaviour. The performance of rockbolts installed in the roadway model under various conditions is discussed and compared with previous research. This paper provides a numerical modelling methodology to study the interaction between rockbolts and the rock mass subject to a variable stress state, rock mass quality, and the presence of rock fractures or joints. It was found that the bearing plates can improve the reinforcing performance of rockbolts.
Juvenile green sturgeon (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) behavior near water-diversion fish screens: experiments in a laboratory swimming flume
Authors: Poletto Jamilynn B. , Cocherell Dennis E. , Ho Natalie , Cech Joseph J. , Klimley A. Peter , Fangue Nann A.
Published: March 2014

Water diversions that extract fresh water for urban, industrial, and agricultural uses, as well as export to southern California, are prevalent throughout the Sacramento–San Joaquin watershed. Many water diversions are fitted with fish-exclusion screens designed to prevent fish from entrainment (i.e., being drawn in). The impact of fish screens on the behavior of migrating juvenile fishes remains largely unknown, especially for threatened species such as sturgeon. We placed individual juvenile green (Acipenser medirostris) or white (Acipenser transmontanus) sturgeon in a laboratory swimming flume in the presence of standard fish screens (2 mm bar spacing) at two field-relevant water velocities (20.4 ± 0.1 and 37.3 ± 0.3 cm·s−1). Fish were tested at 18 °C for 15 min during the day or night and in the presence of possible behavioral deterrents. Behavioral responses, including screen contacts, impingements, and time spent near screens were quantified. Green sturgeon contacted and impinged upon the screens twice as frequently as white sturgeon and also differed in how their behaviors were altered by water velocities and time of day. Our results are informative in developing effective management strategies to mitigate the impacts of water diversions on sturgeon populations and suggest that effective restoration strategies for both species should be considered separately.
Neuroprotective effect of Chunghyuldan from amyloid beta oligomer induced neuroinflammation in vitro and in vivo
Authors: Kim Hyo Geun , Kim Ji-Young , Whang Wei-Wan , Oh Myung Sook
Published: March 2014

Microglia-mediated inflammation is a major pathological mechanism contributing to Alzheimer’s disease (AD), and has been proposed as a potential therapeutic target. Chunghyuldan (CHD; Qingxue-dan in Chinese and Daio-Orengedokuto in Japanese) possesses wide-ranging biological effects, including anti-hyperlipidemic, anti-stroke, anti-inflammatory, and antioxidant activities that could affect neurological functions. In this study, we examined the effects of CHD in in-vitro and in-vivo models of AD induced by the oligomeric form of amyloid-beta (Aβ oligomer), which acts directly on microglia-mediated neuroinflammation to result in neuronal damage and cognitive impairment. CHD at 0.1–100 μg·mL−1 significantly protected PC12 cells and rat primary hippocampal cells from Aβ oligomer1–42 toxicity. In addition, CHD at 1–10 μg·mL−1 inhibited Aβ oligomer1–42 induced production of nitric oxide, tumor necrosis factor-α, and interleukin-1β in microglial cells. In an in-vivo AD model, administration of CHD (50 mg·(kg body mass)−1, for 5 days, per oral) inhibited the activation of astrocytes and microglia in the dentate gyrus and neuronal damage in the CA1 of the ipsilateral hippocampus. Moreover, CHD ameliorated cognitive impairment induced by Aβ oligomer1–42 toxicity. These results demonstrate the neuroprotective effects of CHD through inhibition of microglia-mediated neuroinflammation in in-vitro and in-vivo AD-like models induced by Aβ oligomer1–42 toxicity.
Assessing prehistoric genetic structure and diversity of North American elk (Cervus elaphus) populations in Alberta, Canada
Authors: Speller C.F. , Kooyman B. , Rodrigues A.T. , Langemann E.G. , Jobin R.M. , Yang D.Y.
Published: March 2014

North American elk (Cervus elaphus L., 1758) are an important component of Canada’s natural ecosystems. Overhunting and habitat decline in the 19th century led to the near eradication of Rocky Mountain elk (Cervus elaphus nelsoni Bailey, 1935) and Manitoban elk (Cervus elaphus manitobensis Millais, 1915) within Alberta. Though elk populations have been restored within provincial and national parks, it is unknown to what degree historic population declines affected overall genetic diversity and population structuring of the two subspecies. This study targeted 551 bp of mitochondrial D-loop DNA from 50 elk remains recovered from 16 archaeological sites (2260 BCE (before common era) to 1920 CE (common era)) to examine the former genetic diversity and population structure of Alberta’s historic elk populations. Comparisons of ancient and modern haplotype and nucleotide diversity suggest that historic population declines reduced the mitochondrial diversity of Manitoban elk, while translocation of animals from Yellowstone National Park in the early 20th century served to maintain the diversity of Rocky Mountain populations. Gene flow between the two subspecies was significantly higher in the past than today, suggesting that the two subspecies previously formed a continuous population. These data on precontact genetic diversity and gene flow in Alberta elk provide essential baseline data integral for elk management and conservation in the province.
Orbifold Morse–Smale–Witten complexes
Authors: Cho Cheol-Hyun , Hong Hansol
Published: March 2014

Given a Morse–Smale function on an effective orientable orbifold, we construct its Morse–Smale–Witten complex. We show that critical points of a certain type have to be discarded to build a complex properly, and that gradient flows should be counted with suitable weights. Its homology is proven to be isomorphic to the singular homology of the quotient space under the self-indexing assumption. For a global quotient orbifold [M/G], such a complex can be understood as the G-invariant part of the Morse complex of M, where the G-action on generators of the Morse complex has to be defined including orientation spaces of unstable manifolds at the critical points. Alternatively in the case of global quotients, we introduce the notion of weak group actions on Morse–Smale–Witten complexes for non-invariant Morse–Smale functions on M, which give rise to genuine group actions on the level of homology.
Neargeodesics in John domains in Banach spaces
Authors: Li Yaxiang
Published: March 2014

Let E be a real Banach space with dimension at least 2. In this paper, we prove that if D ⊂ E is a John domain which is homeomorphic to an inner uniform domain via a CQH map, then each neargeodesic in D is a cone arc.
Some rigidity theorems of harmonic maps between Finsler manifolds
Authors: He Qun , Zheng Daxiao
Published: March 2014

This paper is to study further properties of harmonic maps between Finsler manifolds. It is proved that any conformal harmonic map from an n(>2)-dimensional Finsler manifold to a Finsler manifold must be homothetic and some rigidity theorems for harmonic maps between Finsler manifolds are given, which improve some results in earlier papers and generalize Eells–Sampson's theorem and Sealey's theorem in Riemannian Geometry.
Numerical simulation of unsteady double-diffusive natural convection within an inclined parallelepipedic enclosure
Authors: Oueslati Fakher , Ben-Beya Brahim , Lili Taieb
Published: March 2014

Unsteady three-dimensional (3D) double diffusive convection in tilted enclosure having a parallelepipedic shape has been analyzed numerically. The governing unsteady, 3D flow, energy and concentration transport equations, have been solved using an accelerated multigrid implicit volume method. Main attention was paid to the effects of the Rayleigh number Ra , buoyancy ratio N and the inclination angle γ of the cavity on the flow structure and heat and mass transfer rates. Typical distributions of velocity contours, temperature and concentration fields in wide range of defining parameters 103 ≤ Ra ≤ 2 × 104, -5 ≤ N ≤ 5 have been obtained. It is found, that the optimal heat and mass transfer rates for the aiding situation have been observed at two particular inclination angles namely 30° and 75° about the horizontal direction. It should be noted that the flow undergoes a periodic behavior for particular parameters Ra = 104 and γ = 75° according to the aiding flow case. The results also suggest that when N is in range -2 ≤ N ≤ -0.6, the flow continues to be three-dimensional keeping different heat and mass rates. Furthermore, it has been argued that the 2D assumption can be adopted for the 3D flows when the buoyancy ratio N is in range (-0.5–0).
Dynamic behavior and constitutive modeling of magnesium alloys AZ91D and AZ31B under high strain rate compressive loading
Authors: Xiao Jing , Ahmad Iram Raza , Shu D. W.
Published: March 2014

The dynamic stress–strain characteristics of magnesium alloys have not been sufficiently studied experimentally. Thus, the present work investigated compressive dynamic stress–strain characteristics of two representative magnesium alloys: AZ91D and AZ31B at high strain rates and elevated temperatures. In order to use the stress–strain characteristics in numerical simulations to predict the impact response of components, the stress–strain characteristics must be modeled. The most common approach is to use accepted constitutive laws. The results from the experimental study of the response of magnesium alloys AZ91D and AZ31B under dynamic compressive loading, at different strain rates and elevated temperatures are presented here. Johnson–Cook model was used to best fit the experimental data. The material parameters required by the model were obtained and the resultant stress–strain curves of the two alloys for each testing condition were plotted. It is found that the dynamic stress–strain relationship of both magnesium alloys are strain rate and temperature dependent and can be described reasonably well at high strain rates and room temperature by Johnson–Cook model except at very low strains. This might be due to the fact that the strain rate is not strictly constant in the early stage of deformation.
EFFECT OF POLISHING ON THE FRICTION BEHAVIORS AND CUTTING PERFORMANCE OF BORON-DOPED DIAMOND FILMS ON WC-Co INSERTS
Authors: WANG LIANG , SHEN BIN , SUN FANGHONG , ZHANG ZHIMING
Published: March 2014

Boron doped ( B -doped) diamond films are deposited onto WC- Co inserts by HFCVD with the mixture of acetone, trimethyl borate ( C 3 H 9 BO 3) and H 2. The as-deposited B -doped diamond films are characterized with scanning electron microscope (SEM), X-ray diffraction (XRD) spectroscopy, Raman spectroscopy, 3D surface topography based on white-light interferometry and Rockwell hardness tester. The effects of mechanical polishing on the friction behavior and cutting performance of B -doped diamond are evaluated by ball-on-plate type reciprocating tribometer and turning of aluminum alloy 7075 materials, respectively. For comparison, the same tests are also conducted for the bare WC- Co inserts with smooth surface. Friction tests suggest that the unpolished and polished B -doped diamond films possess relatively low fluctuation of friction coefficient than as-received bare WC- Co samples. The average stable friction coefficient for B -doped diamond films decreases apparently after mechanical polishing. The values for WC- Co sample, unpolished and polished B -doped diamond films are approximately 0.38, 0.25 and 0.11, respectively. The cutting results demonstrate that the low friction coefficient and high adhesive strength of B -doped diamond films play an essential role in the cutting performance enhancement of the WC- Co inserts. However, the mechanical polishing process may lower the adhesive strength of B -doped diamond films. Consequently, the polished B -doped diamond coated inserts show premature wear in the machining of adhesive aluminum alloy materials.
Preparation of Magnetorheological Fluid and Study on Its Rheological Properties
Authors: Kolekar Shreedhar
Published: March 2014

The present paper focuses on preparation and process of the magnetorheological (MR) fluid whose carrier fluid is silicone-based oil and its additive is the commercial grease with different concentration of iron particles. General properties of MR fluid are discussed and rheological properties like shear rate, shear stress, viscosity of MR fluid can be found by using cone-and-plate sensor system-type rheometer. The result shows that shear stress as a function of magnetic flux density and viscosity does not strictly scale with iron loading.
EFFECT OF THIOPHENE IN BITHIAZOLE-BRIDGED SENSITIZERS ON THE PERFORMANCE OF DYE-SENSITIZED SOLAR CELLS
Authors: ZHANG XIAOYU , GUO FULING , LI XIN , HE JINXIANG , WU WENJUN , ÅGREN HANS , HUA JIANLI
Published: March 2014

In this paper, we have designed and synthesized four bithiazole-bridged sensitizers (BT-T2, TBT-T2, BT-T3 and TBT-T3) with triphenylamine and indoline as the donor segment and applied them to dye-sensitized solar cells (DSSCs). For triphenylamine-based sensitizers as BT-T2 and TBT-T2, adding one thiophene unit between triphenylamine donor and bithiazole moiety not only led to bathochromic shift of the maximum absorption and increase of molar extinction coefficient, but also enhanced the photovoltaic conversion efficiency from 7.12% of BT-T2 to 7.51% of TBT-T2. But for indoline-based sensitizers as BT-T3 and TBT-T3, adding one thiophene unit between indoline donor and bithiazole moiety resulted in hypochromatic shift instead of bathochromic shift. We employed the density functional theory (DFT) calculations to further investigate the influence of the thiophene unit on their optical and electronic properties and photovoltaic performance of corresponding DSSC devices. Given the results, a reasonable explanation is the introduction of thiophene unit suppressed the intramolecular charge transfer and charge separation in the conjugation system of indoline-based sensitizer, which led to the hypochromatic shift of the maximum absorption wavelength and finally the low J sc . Since the J sc dropped sharply from 15.26 mAcm-2 to 4.52 mAcm-2, the photovoltaic conversion efficiency decreased dramatically from 7.86% to 1.93%.
A delayed SEIRS epidemic model with impulsive vaccination and nonlinear incidence rate
Authors: Zhang Jiancheng , Sun Jitao
Published: March 2014

In this paper, a delayed SEIRS epidemic model with nonlinear incidence rate and impulsive vaccination is investigated. In vaccination strategy, we perform impulsive vaccination of newborn infants. Using the discrete dynamic system determined by stroboscopic map, we obtain an infection-free periodic solution and establish conditions, on which the solution is globally attractive. We also conclude that the disease is permanent if the parameters of the model satisfy appropriate conditions. Finally, we illustrate the effectiveness of our theorems with numerical simulation. The results obtained in this paper are a good extension of the results obtained in [J. Hou and Z. Teng, Continuous and impulsive vaccination of SEIR epidemic models with saturation incidence rate, Math. Comput. Simulat.79 (2009) 3038–3054] to the corresponding delayed SEIRS epidemic model with nonlinear incidence rate and impulsive vaccination.
Traveling wavefronts of a nonlinear reaction–diffusion model of tumor growth under the acid environment
Authors: Zhu Huiyan , Luo Yang , Wang Xiufang
Published: March 2014

In this paper, a reaction–diffusion model describing temporal development of tumor tissue, normal tissue and excess H+ ion concentration is considered. Based on a combination of perturbation methods, the Fredholm theory and Banach fixed point theorem, we theoretically justify the existence of the traveling wave solution for this model.
Credit coordinate ratings with corresponding credit rating agencies and regulations
Authors: Li Weiping
Published: March 2014

This paper develops a coordinate rating for Credit Rating Agencies (CRAs) in the rating market. We first show that there is a necessary condition for the restructured sub-portfolios to have no-arbitrage principle for coordinate ratings. The coordinate rating is not only a natural extension of a single rating, but also reduces the rating bias and increases the rating accuracy. We solve the voluntary-disclosure decision problem for the issuer in terms of coordinate ratings. Furthermore, we show that the complexities of sub-portfolios do reduce the incentive to shop for the coordinate rating by comparing it with the incentive to shop for a single rating. The correlation among sub-portfolios also affect the incentive to shop in the coordinate rating. We advocate four principles for the credit rating system, from adapting coordinate ratings and reducing conflicts of interest to encouraging competition among CRAs and ensuring incentive alignment. We also build a model with disapproval correlation among CRAs and show that the probability of the joint disapproval is extremely sensitive to the disapproval correlation, even though the correlation may be very small in absolute value. Under an approval arrangement from the regulator in terms of the default rate within a CRA, we show that there exists a sub-game perfect equilibrium in which both approved CRAs provide correct coordinate ratings.
Using the voids to fill the gaps: caves, time, and stratigraphy
Authors: Plotnick Roy E. , Kenig Fabien , Scott Andrew C.
Published: March 2014

Karstification produces a unique and spatially complex architecture of accommodation space for the accumulation of later sediments. The sedimentary record within caves can act as a repository for stratigraphic and palaeoenvironmental information that has been locally removed by subsequent surface erosion. Caves and karst also allow for the preservation of biota not usually found in the fossil record. Pennsylvanian palaeokarst from Illinois, USA, illustrate the potential of ancient caves as a home for ‘lost stratigraphy’. These palaeocaves have dissolutional features associated with contemporaneous sediment influx (paragenesis), indicating that speleogenesis and cave sediment deposition were synchronous. These features also provide evidence of changing water tables. The fill within the caves suggests multiple flood events on the surface. The enclosed biota contains rare upland plants, such as conifers, as well as scorpions. Both plants and animals preserve original organic constituents. The presence of charcoal, as well as diagnostic polyaromatic hydrocarbons, point to wildfires and thus dry episodes on the land surface. The cave fills are outliers from correlative formations in the region. The filled voids of these ancient caves thus fill palaeontological, palaeoenvironmental, and stratigraphic gaps.
Fatty acid synthase is required for mammary gland development and milk production during lactation
Authors: Suburu Janel , Shi Lihong , Wu Jiansheng , Wang Shihua , Samuel Michael , Thomas Michael J. , Kock Nancy D. , Yang Guangyu , Kridel Steven , Chen Yong Q.
Published: March 2014

The mammary gland is one of the few adult tissues that strongly induce de novo fatty acid synthesis upon physiological stimulation, suggesting that fatty acid is important for milk production during lactation. The committed enzyme to perform this function is fatty acid synthase (FASN). To determine whether de novo fatty acid synthesis is obligatory or dietary fat is sufficient for mammary gland development and function during lactation, Fasn was specifically knocked out in mouse mammary epithelial cells. We found that deletion of Fasn hindered the development and induced the premature involution of the lactating mammary gland and significantly decreased medium- and long-chain fatty acids and total fatty acid contents in the milk. Consequently, pups nursing from Fasn knockout mothers experienced growth retardation and preweanling death, which was rescued by cross-fostering pups to a lactating wild-type mother. These results demonstrate that FASN is essential for the development, functional competence, and maintenance of the lactating mammary gland.
Effect of Tumor Necrosis Factor Family Member LIGHT (TNFSF14) on the Activation of Basophils and Eosinophils Interacting with Bronchial Epithelial Cells
Authors: Qiu Huai Na , Wong Chun Kwok , Dong Jie , Lam Christopher Wai-Kei , Cai Zhe
Published: March 2014

Allergic asthma can cause airway structural remodeling, involving the accumulation of extracellular matrix and thickening of smooth muscle. Tumor necrosis factor (TNF) family ligand LIGHT (TNFSF14) is a cytokine that binds herpesvirus entry mediator (HVEM)/TNFRSF14 and lymphotoxinβreceptor (LTβR). LIGHT induces asthmatic cytokine IL-13 and fibrogenic cytokine transforming growth factor-βrelease from allergic asthma-related eosinophils expressing HVEM and alveolar macrophages expressing LTβR, respectively, thereby playing crucial roles in asthmatic airway remodeling. In this study, we investigated the effects of LIGHT on the coculture of human basophils/eosinophils and bronchial epithelial BEAS-2B cells. The expression of adhesion molecules, cytokines/chemokines, and matrix metalloproteinases (MMP) was measured by flow cytometry, multiplex, assay or ELISA. Results showed that LIGHT could significantly promote intercellular adhesion, cell surface expression of intercellular adhesion molecule-1, release of airway remodeling-related IL-6, CXCL8, and MMP-9 from BEAS-2B cells upon interaction with basophils/eosinophils, probably via the intercellular interaction, cell surface receptors HVEM and LTβR on BEAS-2B cells, and extracellular signal-regulated kinase, p38 mitogen activated protein kinase, and NF-κB signaling pathways. The above results, therefore, enhance our understanding of the immunopathological roles of LIGHT in allergic asthma and shed light on the potential therapeutic targets for airway remodeling.
Adaptive Neuro-Fuzzy Inference System for Classification of Background EEG Signals from ESES Patients and Controls
Authors: Yang Zhixian , Wang Yinghua , Ouyang Gaoxiang
Published: March 2014

Background electroencephalography (EEG), recorded with scalp electrodes, in children with electrical status epilepticus during slow-wave sleep (ESES) syndrome and control subjects has been analyzed. We considered 10 ESES patients, all right-handed and aged 3–9 years. The 10 control individuals had the same characteristics of the ESES ones but presented a normal EEG. Recordings were undertaken in the awake and relaxed states with their eyes open. The complexity of background EEG was evaluated using the permutation entropy (PE) and sample entropy (SampEn) in combination with the ANOVA test. It can be seen that the entropy measures of EEG are significantly different between the ESES patients and normal control subjects. Then, a classification framework based on entropy measures and adaptive neuro-fuzzy inference system (ANFIS) classifier is proposed to distinguish ESES and normal EEG signals. The results are promising and a classification accuracy of about 89% is achieved.