bluuebunny/crossref_metadata_2025 huggingface dataset:
International law: armed groups in a state-centric system
Authors: Daboné Zakaria
Published: March 2012

What is the position of non-state armed groups in public international law, a system conceived for and by states? This article considers the question, mainly in the light of jus ad bellum and jus in bello. It shows that, while armed groups essentially trigger the application of jus ad bellum, they are not themselves endowed with a right to peace. Jus in bello confers rights and obligations on armed groups, but in the context of an unequal relationship with the state. This inequality before the law is strikingly illustrated by the regulation of detention practised by armed groups in non-international armed conflicts. Despite the significant role that they play in modern-day conflicts, armed groups constitute an ‘anomaly’ in a legal system that continues to be state-centric.
Impact of tide‐topography interactions on basal melting of Larsen C Ice Shelf, Antarctica
Authors: Mueller R. D. , Padman L. , Dinniman M. S. , Erofeeva S. Y. , Fricker H. A. , King M. A.
Published: March 2012

Basal melting of ice shelves around Antarctica contributes to formation of Antarctic Bottom Water and can affect global sea level by altering the offshore flow of grounded ice streams and glaciers. Tides influence ice shelf basal melt rate (wb) by contributing to ocean mixing and mean circulation as well as thermohaline exchanges with the ice shelf. We use a three‐dimensional ocean model, thermodynamically coupled to a nonevolving ice shelf, to investigate the relationship between topography, tides, andwb for Larsen C Ice Shelf (LCIS) in the northwestern Weddell Sea, Antarctica. Using our best estimates of ice shelf thickness and seabed topography, we find that the largest modeled LCIS melt rates occur in the northeast, where our model predicts strong diurnal tidal currents (∼0.4 m s−1). This distribution is significantly different from models with no tidal forcing, which predict largest melt rates along the deep grounding lines. We compare several model runs to explore melt rate sensitivity to geometry, initial ocean potential temperature (θ0), thermodynamic parameterizations of heat and freshwater ice‐ocean exchange, and tidal forcing. The resulting range of LCIS‐averagedwb is ∼0.11–0.44 m a−1. The spatial distribution of wb is very sensitive to model geometry and thermodynamic parameterization while the overall magnitude of wb is influenced by θ0. These sensitivities in wbpredictions reinforce a need for high‐resolution maps of ice draft and sub‐ice‐shelf seabed topography together with ocean temperature measurements at the ice shelf front to improve representation of ice shelves in coupled climate system models.
Patch dynamics and stability in steep, rough streams
Authors: Yager E. M. , Dietrich W. E. , Kirchner J. W. , McArdell B. W.
Published: March 2012

The beds of steep streams are typically composed of relatively immobile boulders and more mobile patches of gravel and cobbles. Little is known about how variability in flow and sediment flux affect the area, thickness, composition, and grain mobility of sediment patches. To better understand patch dynamics, we measured flow, sediment transport, and bed properties in two steep channels. Patches close to the thalweg varied in area, thickness, and grain size, whereas those outside the thalweg did not. Local variations in transport of several orders of magnitude occurred, even on a patch with a spatially homogeneous grain size distribution. During moderate flow events, partial to selective transport dominated on the entire channel bed and all individual patches. Tracer particles moved freely between different patch classes (e.g., fine and coarse patches exchanged particles), and relatively fine sediment on all patch classes began motion at the same shear stress. Therefore, the selective transport observed for the entire bed was not a result of the preferential transport of only fine patches, but the high relative mobility of finer sediment on all patches. Our results suggest that local flow and sediment supply, and not spatial grain size variations, were the primary drivers of local bed load transport variability. The use of reach‐averaged flow properties to understand local patch dynamics may not be applicable.
Trends in sunspots and North Atlantic sea level pressure
Authors: van Loon Harry , Brown Jeremiah , Milliff Ralph F.
Published: March 2012

We analyze the periods 1878–1944 and 1944–2008. The quasi‐stationary wave in the North Atlantic region was stronger and the baroclinity steeper in 1878–1944 than in 1944–2008. The North Atlantic Oscillation Index—as defined by the Climate Research Unit, University of East Anglia—was higher in the former period too. We illustrate these statements by maps of sea level pressure and air temperature at the surface. The long‐term trends in the North Atlantic Oscillation Index are linked to the trend in sunspot number such that when, in the mean, the sunspot numbers were high (Gleissberg maxima) the trends in the two quantities were parallel; and when the mean sunspot numbers were low (Gleissberg minima) the trends in the North Atlantic Oscillation Index and sunspots were opposite. We find the connections between the trends statistically significant, and we infer that the level of solar activity played a role in the trends of the past two centuries in the North Atlantic region. However, we cannot as yet provide a mechanism linking the solar trends to those in the atmosphere and ocean, but as a step toward an explanation, the equator to pole temperature gradient is steeper in a Gleissberg minimum than in a maximum.
A Nonlinear Dynamical Theory of Cell Injury
Authors: DeGracia Donald J , Huang Zhi-Feng , Huang Sui
Published: March 2012

Multifactorial injuries, such as ischemia, trauma, etc., have proven stubbornly elusive to clinical therapeutics, in spite of the binary outcome of recovery or death. This may be due, in part, to the lack of formal approaches to cell injury. We present a minimal system of nonlinear ordinary differential equations describing a theory of cell injury dynamics. A mutual antagonism between injury-driven total damage and total induced stress responses gives rise to attractors representing recovery or death. Solving across a range of injury magnitudes defines an ‘injury course’ containing a well-defined tipping point between recovery and death. Via the model, therapeutics is the diverting of a system on a pro-death trajectory to a pro-survival trajectory on bistable phase planes. The model plausibly explains why laboratory-based therapies have tended to fail clinically. A survival outcome is easy to achieve when lethal injury is close to the tipping point, but becomes progressively difficult as injury magnitudes increase, and there is an upper limit to salvageable injuries. The model offers novel insights into cell injury that may assist in overcoming barriers that have prevented development of clinically effective therapies for multifactorial conditions, as exemplified by brain ischemia.
Pathophysiology of the Neurovascular Unit: Disease Cause or Consequence?
Authors: Stanimirovic Danica B , Friedman Alon
Published: March 2012

Pathophysiology of the neurovascular unit (NVU) is commonly seen in neurological diseases. The typical features of NVU pathophysiology include tissue hypoxia, inflammatory and angiogenic activation, as well as initiation of complex molecular interactions between cellular (brain endothelial cells, astroctyes, pericytes, inflammatory cells, and neurons) and acellular (basal lamina) components of the NVU, jointly resulting in increased blood–brain barrier permeability, brain edema, neurovascular uncoupling, and neuronal dysfunction and damage. The evidence of important role of the brain vascular compartment in disease pathogenesis has elicited the debate whether the primary vascular events may be a cause of the neurological disease, as opposed to a mere participant recruited by a primary neuronal origin of pathology? Whereas some hereditary and acquired cerebral angiopathies could be considered a primary cause of neurological symptoms of the disease, the epidemiological studies showing a high degree of comorbidity among vascular disease and dementias, including Alzheimer's disease, as well as migraine and epilepsy, suggested that primary vascular pathology may be etiological factor causing neuronal dysfunction or degeneration in these diseases. This review focuses on recent hypotheses and evidence, suggesting that pathophysiology of the NVU may be initiating trigger for neuronal pathology and subsequent neurological manifestations of the disease.
Single Slice vs. Volumetric MR Assessment of Visceral Adipose Tissue: Reliability and Validity Among the Overweight and Obese
Authors: Maislin Greg , Ahmed Murtuza M. , Gooneratne Nalaka , Thorne‐Fitzgerald Matt , Kim Christopher , Teff Karen , Arnardottir Erna S. , Benediktsdottir Bryndis , Einarsdottir Hildur , Juliusson Sigurdur , Pack Allan I. , Gislason Thorarinn , Schwab Richard J.
Published: March 2012

Visceral adipose tissue (VAT) is associated with abnormal cardiovascular and metabolic profiles. Total VAT volume of the abdominal compartment by magnetic resonance imaging (MRI) is the gold‐standard measurement for VAT but is costly and time consuming. Prior studies suggest VAT area on a single slice MR image may serve as a surrogate for total VAT volume but it is unknown if this relationship is maintained in overweight and obese men and women. Untreated sleep apnea subjects enrolled into the Icelandic Sleep Apnea Cohort (ISAC) underwent abdominal MRI. VAT area and subcutaneous adipose tissue (SAT) area at the L2‐L3 and L4‐L5 interspaces and total VAT and SAT volumes were determined by manual examination using image analysis software; 539 men and 129 women with mean ages of 54.1 and 58.8 years and mean BMI of 32.2 kg/m2 and 33.7 kg/m2, respectively, were studied. Mean total VAT volume was 40% smaller and mean total SAT was 25% larger among females compared with males. The correlation with VAT volume was significantly larger for L2‐L3 VAT area (r = 0.96) compared to L4‐L5 VAT area (r = 0.83). The difference in correlation coefficients was statistically significant (nonparametric bootstrap P < 0.001 with 95% confidence interval (CI) for the difference from 0.11 to 0.15. VAT area at L2‐L3 was also significantly better correlated with VAT volume than traditional anthropometric variables. Linear regression analyses demonstrated that L2‐L3 area alone was sufficient for predicting total VAT volume and that the nature of the linear association was maintained across all levels of obesity and in both genders.
Residual Obesity Stigma: An Experimental Investigation of Bias Against Obese and Lean Targets Differing in Weight‐Loss History
Authors: Latner Janet D. , Ebneter Daria S. , O'Brien Kerry S.
Published: March 2012

This study investigated stigma directed at formerly obese persons who lost weight and became lean (through behavioral or surgical methods), or lost weight but remained obese, relative to weight‐stable obese and weight‐stable lean persons. This study also compared stigma directed at obese persons following exposure to descriptions of persons who lost weight vs. remained weight stable. In a between‐subject experimental design, participants (n = 273) were randomly assigned to read vignettes describing targets varying across two dimensions, weight stability (i.e., weight stable or weight lost) and current weight (i.e., currently obese or currently lean). Participants completed measures of stigma against specific targets and measures of stigma against obese individuals in general. Lean individuals who were formerly obese were stigmatized more on attractiveness than weight‐stable lean individuals, and as much as currently obese individuals. Stigma across domains was greater among currently obese individuals (regardless of whether they had lost weight from a higher weight) than among currently lean individuals. After reading vignettes describing weight loss, participants demonstrated greater obesity stigma than after reading vignettes describing weight‐stable individuals. These results suggest that residual stigma remains against people who have previously been obese, even when they have lost substantial amounts of weight and regardless of their weight‐loss method. Exposure to portrayals of the malleability of body weight, such as those promoted in the popular media, may significantly worsen obesity stigma.
Cell signalling by reactive lipid species: new concepts and molecular mechanisms
Authors: Higdon Ashlee , Diers Anne R. , Oh Joo Yeun , Landar Aimee , Darley-Usmar Victor M.
Published: March 2012

The process of lipid peroxidation is widespread in biology and is mediated through both enzymatic and non-enzymatic pathways. A significant proportion of the oxidized lipid products are electrophilic in nature, the RLS (reactive lipid species), and react with cellular nucleophiles such as the amino acids cysteine, lysine and histidine. Cell signalling by electrophiles appears to be limited to the modification of cysteine residues in proteins, whereas non-specific toxic effects involve modification of other nucleophiles. RLS have been found to participate in several physiological pathways including resolution of inflammation, cell death and induction of cellular antioxidants through the modification of specific signalling proteins. The covalent modification of proteins endows some unique features to this signalling mechanism which we have termed the ‘covalent advantage’. For example, covalent modification of signalling proteins allows for the accumulation of a signal over time. The activation of cell signalling pathways by electrophiles is hierarchical and depends on a complex interaction of factors such as the intrinsic chemical reactivity of the electrophile, the intracellular domain to which it is exposed and steric factors. This introduces the concept of electrophilic signalling domains in which the production of the lipid electrophile is in close proximity to the thiol-containing signalling protein. In addition, we propose that the role of glutathione and associated enzymes is to insulate the signalling domain from uncontrolled electrophilic stress. The persistence of the signal is in turn regulated by the proteasomal pathway which may itself be subject to redox regulation by RLS. Cell death mediated by RLS is associated with bioenergetic dysfunction, and the damaged proteins are probably removed by the lysosome-autophagy pathway.
PI3K signalling in B- and T-lymphocytes: new developments and therapeutic advances
Authors: So Lomon , Fruman David A.
Published: March 2012

Activation of PI3K (phosphoinositide 3-kinase) is a shared response to engagement of diverse types of transmembrane receptors. Depending on the cell type and stimulus, PI3K activation can promote different fates including proliferation, survival, migration and differentiation. The diverse roles of PI3K signalling are well illustrated by studies of lymphocytes, the cells that mediate adaptive immunity. Genetic and pharmacological experiments have shown that PI3K activation regulates many steps in the development, activation and differentiation of both B- and T-cells. These findings have prompted the development of PI3K inhibitors for the treatment of autoimmunity and inflammatory diseases. PI3K activation, however, has both positive and negative roles in immune system activation. Consequently, although PI3K suppression can attenuate immune responses it can also enhance inflammation, disrupt peripheral tolerance and promote autoimmunity. An exciting discovery is that a selective inhibitor of the p110δ catalytic isoform of PI3K, CAL-101, achieves impressive clinical efficacy in certain B-cell malignancies. A model is emerging in which p110δ inhibition disrupts signals from the lymphoid microenvironment, leading to release of leukaemia and lymphoma cells from their protective niche. These encouraging findings have given further momentum to PI3K drug development efforts in both cancer and immune diseases.
Mutual co-regulation between GPI-N-acetylglucosaminyltransferase and ergosterol biosynthesis in Candida albicans
Authors: Victoria Guiliana Soraya , Yadav Bhawna , Hauhnar Lalremruata , Jain Priyanka , Bhatnagar Shilpi , Komath Sneha Sudha
Published: March 2012

A novel co-regulation exists between the first step of GPI (glycosylphosphatidylinositol) anchor biosynthesis and the rate-determining step of ergosterol biosynthesis in Candida albicans. Depleting CaGpi19p, an accessory subunit of the enzyme complex that initiates GPI biosynthesis, down-regulates ERG11, altering ergosterol levels and drug response. This effect is specific to CaGpi19p depletion and is not due to cell wall defects or GPI deficiency. Additionally, down-regulation of ERG11 down-regulates CaGPI19 and GPI biosynthesis.
Does phosphorus stimulate the effect of elevated [CO2] on growth and symbiotic nitrogen fixation of grain and pasture legumes?
Authors: Lam Shu Kee , Chen Deli , Norton Rob , Armstrong Roger
Published: March 2012

The effect of elevated [CO2] (700 μmol/mol) and phosphorus (P) supply on the growth and symbiotic N2 fixation of chickpea (Cicer arietinum L.), field pea (Pisum sativum L.) and barrel medic (Medicago truncatula Gaertn.) were investigated in the glasshouse. The effect of elevated [CO2] on the growth and N2 fixation at various growth stages of the chickpea and field pea plants (grown on a Vertosol) were also examined. Elevated [CO2] generally increased the aboveground biomass of chickpea (by 18–64%), field pea (by 24–57%) and barrel medic (by 49–82%), but the effect was greater when P was non-limiting. Elevated [CO2] only stimulated grain yield of chickpea (by 70%) and field pea (by 21%) if P supply was adequate. Elevated [CO2] reduced the grain protein concentration of chickpea (by 17–18%) regardless of P input, but increased that of field pea (by 11%) when soil P was limiting but had no effect at adequate P. The percentage of shoot N derived from the atmosphere (%Ndfa) of the three legumes was unaffected by elevated [CO2] regardless of soil P supply. Elevated [CO2] increased the amount of N fixed by chickpea (by 20–86%), field pea (by 44–51%) and barrel medic (by 114–250%) under P fertilisation, but had no significant effect when soil P was deficient. These results suggest that the predictions of future climates on the potential contribution of legumes to maintaining soil N fertility will depend on the particular response of a species to soil P status.
Intestinal CX
3
C chemokine receptor 1
high
(CX
3
CR1
high
) myeloid cells prevent T-cell-dependent colitis
Authors: Kayama Hisako , Ueda Yoshiyasu , Sawa Yukihisa , Jeon Seong Gyu , Ma Ji Su , Okumura Ryu , Kubo Atsuko , Ishii Masaru , Okazaki Taku , Murakami Masaaki , Yamamoto Masahiro , Yagita Hideo , Takeda Kiyoshi
Published: March 2012

Adequate activation of CD4
+
T lymphocytes is essential for host defense against invading pathogens; however, exaggerated activity of effector CD4
+
T cells induces tissue damage, leading to inflammatory disorders such as inflammatory bowel diseases. Several unique subsets of intestinal innate immune cells have been identified. However, the direct involvement of innate immune cell subsets in the suppression of T-cell-dependent intestinal inflammation is poorly understood. Here, we report that intestinal CX
3
C chemokine receptor 1
high
(CX
3
CR1
high
) CD11b
+
CD11c
+
cells are responsible for prevention of intestinal inflammation through inhibition of T-cell responses. These cells inhibit CD4
+
T-cell proliferation in a cell contact-dependent manner and prevent T-cell-dependent colitis. The suppressive activity is abrogated in the absence of the IL-10/Stat3 pathway. These cells inhibit T-cell proliferation by two steps. Initially, CX
3
CR1
high
CD11b
+
CD11c
+
cells preferentially interact with T cells through highly expressed intercellular adhesion molecule-1/vascular cell adhesion molecule-1; then, they fail to activate T cells because of defective expression of CD80/CD86. The IL-10/Stat3 pathway mediates the reduction of CD80/CD86 expression. Transfer of wild-type CX
3
CR1
high
CD11b
+
CD11c
+
cells prevents development of colitis in myeloid-specific Stat3-deficient mice. Thus, these cells are regulatory myeloid cells that are responsible for maintaining intestinal homeostasis.
Fanconi anemia (FA) binding protein FAAP20 stabilizes FA complementation group A (FANCA) and participates in interstrand cross-link repair
Authors: Leung Justin Wai Chung , Wang Yucai , Fong Ka Wing , Huen Michael Shing Yan , Li Lei , Chen Junjie
Published: March 2012

The Fanconi anemia (FA) pathway participates in interstrand cross-link (ICL) repair and the maintenance of genomic stability. The FA core complex consists of eight FA proteins and two Fanconi anemia-associated proteins (FAAP24 and FAAP100). The FA core complex has ubiquitin ligase activity responsible for monoubiquitination of the FANCI-FANCD2 (ID) complex, which in turn initiates a cascade of biochemical events that allow processing and removal of cross-linked DNA and thereby promotes cell survival following DNA damage. Here, we report the identification of a unique component of the FA core complex, namely, FAAP20, which contains a RAD18-like ubiquitin-binding zinc-finger domain. Our data suggest that FAAP20 promotes the functional integrity of the FA core complex via its direct interaction with the FA gene product, FANCA. Indeed, somatic knockout cells devoid of FAAP20 displayed the hallmarks of FA cells, including hypersensitivity to DNA cross-linking agents, chromosome aberrations, and reduced FANCD2 monoubiquitination. Taking these data together, our study indicates that FAAP20 is an important player involved in the FA pathway.
Genetic dating indicates that the Asian–Papuan admixture through Eastern Indonesia corresponds to the Austronesian expansion
Authors: Xu Shuhua , Pugach Irina , Stoneking Mark , Kayser Manfred , Jin Li ,   The HUGO Pan-Asian SNP Consortium
Published: March 2012

Although the Austronesian expansion had a major impact on the languages of Island Southeast Asia, controversy still exists over the genetic impact of this expansion. The coexistence of both Asian and Papuan genetic ancestry in Eastern Indonesia provides a unique opportunity to address this issue. Here, we estimate recombination breakpoints in admixed genomes based on genome-wide SNP data and date the genetic admixture between populations of Asian vs. Papuan ancestry in Eastern Indonesia. Analyses of two genome-wide datasets indicate an eastward progression of the Asian admixture signal in Eastern Indonesia beginning about 4,000–3,000 y ago, which is in excellent agreement with inferences based on Austronesian languages. The average rate of spread of Asian genes in Eastern Indonesia was about 0.9 km/y. Our results indicate that the Austronesian expansion had a strong genetic as well as linguistic impact on Island Southeast Asia, and they significantly advance our understanding of the biological origins of human populations in the Asia–Pacific region.
Antiproliferative small-molecule inhibitors of transcription factor LSF reveal oncogene addiction to LSF in hepatocellular carcinoma
Authors: Grant Trevor J. , Bishop Joshua A. , Christadore Lisa M. , Barot Girish , Chin Hang Gyeong , Woodson Sarah , Kavouris John , Siddiq Ayesha , Gredler Rachel , Shen Xue-Ning , Sherman Jennifer , Meehan Tracy , Fitzgerald Kevin , Pradhan Sriharsa , Briggs Laura A. , Andrews William H. , Sarkar Devanand , Schaus Scott E. , Hansen Ulla
Published: March 2012

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Despite the prevalence of HCC, there is no effective, systemic treatment. The transcription factor LSF is a promising protein target for chemotherapy; it is highly expressed in HCC patient samples and cell lines, and promotes oncogenesis in rodent xenograft models of HCC. Here, we identify small molecules that effectively inhibit LSF cellular activity. The lead compound, factor quinolinone inhibitor 1 (FQI1), inhibits LSF DNA-binding activity both in vitro, as determined by electrophoretic mobility shift assays, and in cells, as determined by ChIP. Consistent with such inhibition, FQI1 eliminates transcriptional stimulation of LSF-dependent reporter constructs. FQI1 also exhibits antiproliferative activity in multiple cell lines. In LSF-overexpressing cells, including HCC cells, cell death is rapidly induced; however, primary or immortalized hepatocytes are unaffected by treatment with FQI1. The highly concordant structure–activity relationship of a panel of 23 quinolinones strongly suggests that the growth inhibitory activity is due to a single biological target or family. Coupled with the striking agreement between the concentrations required for antiproliferative activity (GI
50
s) and for inhibition of LSF transactivation (IC
50
s), we conclude that LSF is the specific biological target of FQIs. Based on these in vitro results, we tested the efficacy of FQI1 in inhibiting HCC tumor growth in a mouse xenograft model. As a single agent, tumor growth was dramatically inhibited with no observable general tissue cytotoxicity. These findings support the further development of LSF inhibitors for cancer chemotherapy.
Growth Rate of the California Sea Cucumber Parastichopus californicus: Measurement Accuracy and Relationships between Size and Weight Metrics
Authors: Hannah Lucie , Duprey Nicholas , Blackburn John , Hand Claudia M. , Pearce Christopher M.
Published: March 2012

Management of the fishery for California sea cucumbers Parastichopus californicus in the Pacific Northwest is limited by a lack of natural growth rate estimates. Growth rates of caged juvenile California sea cucumbers (from Departure Bay, British Columbia) consuming a natural diet for 12 months (September 2008–September 2009) were examined. Growth was low between September and March but significantly increased thereafter, appearing to follow seasonal physiological processes, temperature, and natural sedimentation rates. Over the 12-month period, whole wet weight in air (WWA) increased by an average of 164%, immersed whole weight (IWW) increased by 251%, and the size index (SI) increased by 85%. Average standard growth rates were 0.267%/d for WWA, 0.346%/d for IWW, and 0.169%/d for SI. Measurement accuracy, effects of body content, and relationships between size and weight metrics are discussed. These findings are an important addition to the knowledge of California sea cucumber biology and are valuable for the stock assessment, fisheries management, and aquaculture of this species.

Received January 1, 2011; accepted November 10, 2011
Effectiveness of Seining after Electrofishing to Characterize Stream Fish Communities
Authors: Meador Michael R.
Published: March 2012

The richness and composition of species collected uniquely to electrofishing and subsequent seining efforts were examined at 271 stream sites across the USA by using wadeable electrofishing methods (backpack or barge electrofishing) or boat electrofishing followed by seining. Seining after wadeable electrofishing resulted in the collection of new species at 42% of sites, whereas seining after boat electrofishing resulted in the collection of new species at 87% of sites. Mean percentage of total observed fish species richness that was collected uniquely by seining was 6% (representing one new species, on average) after wadeable electrofishing compared with 18% (four new species, on average) after boat electrofishing. Shannon–Wiener diversity index values were not significantly different between data from combined sampling (electrofishing and seining) and data from wadeable electrofishing (P = 0.490) but were significantly different between boat electrofishing and combined sampling (P = 0.004). Seining efforts after boat electrofishing can provide critical information that allows for a more complete characterization of the fish community. For sampling in wadeable streams, decisions regarding the use of seines should consider the effectiveness of electrofishing at a given site and the use of seines as an alternative primary sampling gear rather than as a supplement to electrofishing.

Received June 22, 2011; accepted November 10, 2011
Edge-localized mode control by electron cyclotron waves in a tokamak plasma
Authors: Rossel J.X. , Moret J.-M. , Coda S. , Sauter O. , Goodman T.P. , Felici F. , Testa D. , Martin Y.
Published: March 2012

Electron cyclotron resonance heating is applied to the edge of a high-confinement (H-mode) plasma featuring type I edge-localized modes (ELMs) in the TCV tokamak. As the deposition location is shifted gradually in a highly controlled manner towards the plasma pressure pedestal, an increase in the ELM frequency by a factor 2 and a decrease in the energy loss per ELM by the same factor are observed, even though the power absorption efficiency is reduced. This unexpected and, as yet, unexplained phenomenon, observed for the first time, runs contrary to the intrinsic type I ELM power dependence and provides a new approach for ELM mitigation.
Lines of minima with no end in Thurston’s boundary of Teichmüller space
Authors: Iguchi Yuki
Published: March 2012

Let

ν
+

\nu ^+

and

ν
−

\nu ^-

be two measured laminations which fill up a hyperbolic surface. Kerckhoff [Duke Math. J. 65 (1992), 187–213] defines a line of minima as a family of surfaces where convex combinations of the hyperbolic length functions of

ν
+

\nu ^+

and

ν
−

\nu ^-

are minimum. This is a proper curve in the Teichmüller space. We show that there exists a line of minima which does not converge in the Thurston compactification of the Teichmüller space of a compact Riemann surface. We also show that the limit set of the line of minima is contained in a simplex on the Thurston boundary.
Discontinuous change in ice cover in Hudson Bay in the 1990s and some consequences for marine birds and their prey
Authors: Gaston Anthony J. , Smith Paul A. , Provencher Jennifer F.
Published: March 2012

Gaston A. J., Smith, P. A., and Provencher, J. F. 2012. Discontinuous change in ice cover in Hudson Bay in the 1990s and some consequences for marine birds and their prey. – ICES Journal of Marine Science, 69: . Arctic ice cover has changed strikingly since the mid-1990s, with the minimum ice extent in the northern hemisphere diminishing by 8.5% per decade since 1981. In the Canadian Arctic, ice cover in June and November showed a step change in the mid-1990s, with little reduction before that. There was a similar step change in northern Hudson Bay. A long-term dataset on marine birds at Coats Island, Nunavut, revealed that many changes in seabird biology also exhibited an abrupt change at, or soon after, the change in ice conditions. This applied to their diet that switched in the 1990s from one dominated by Arctic cod, Boreogadus saida, to one dominated by capelin, Mallotus villosus. Evidence from the proportion of Arctic cod in adult diets suggested that the length of the open-water season may be a good predictor of the switch between Arctic cod and capelin. Other changes, in nestling growth and population trend, may relate to the same ecosystem changes that led to the switch in diet. Abrupt changes, as in the breeding biology of murres at Coats Island, would seem to be characteristic of ecosystem alterations driven by climate change.
Sinorhizobium fredii HH103 rkp-3 Genes Are Required for K-Antigen Polysaccharide Biosynthesis, Affect Lipopolysaccharide Structure and Are Essential for Infection of Legumes Forming Determinate Nodules
Authors: Margaret Isabel , Crespo-Rivas Juan C. , Acosta-Jurado Sebastián , Buendía-Clavería Ana M. , Cubo María T. , Gil-Serrano Antonio , Moreno Javier , Murdoch Piedad S. , Rodríguez-Carvajal Miguel A. , Rodríguez-Navarro Dulce N. , Ruiz-Sainz José E. , Sanjuán Juan , Soto María J. , Vinardell José M.
Published: March 2012

The Sinorhizobium fredii HH103 rkp-3 region has been isolated and sequenced. Based on the similarities between the S. fredii HH103 rkpL, rkpM, rkpN, rkpO, rkpP, and rkpQ genes and their corresponding orthologues in Helicobacter pylori, we propose a possible pathway for the biosynthesis of the S. fredii HH103 K-antigen polysaccharide (KPS) repeating unit. Three rkp-3 genes (rkpM, rkpP, and rkpQ) involved in the biosynthesis of the HH103 KPS repeating unit (a derivative of the pseudaminic acid) have been mutated and analyzed. All the rkp-3 mutants failed to produce KPS and their lipopolysaccharide (LPS) profiles were altered. These mutants showed reduced motility and auto-agglutinated when early-stationary cultures were further incubated under static conditions. Glycine max, Vigna unguiculata (determinate nodule–forming legumes), and Cajanus cajan (indeterminate nodules) plants inoculated with mutants in rkpM, rkpQ, or rkpP only formed pseudonodules that did not fix nitrogen and were devoid of bacteria. In contrast, another indeterminate nodule–forming legume, Glycyrrhiza uralensis, was still able to form some nitrogen-fixing nodules with the three S. fredii HH103 rifampicin-resistant rkp-3 mutants tested. Our results suggest that the severe symbiotic impairment of the S. fredii rkp-3 mutants with soybean, V. unguiculata, and C. cajan is mainly due to the LPS alterations rather than to the incapacity to produce KPS.
Expression of a Single-Chain Variable-Fragment Antibody Against a Fusarium virguliforme Toxin Peptide Enhances Tolerance to Sudden Death Syndrome in Transgenic Soybean Plants
Authors: Brar Hargeet K. , Bhattacharyya Madan K.
Published: March 2012

Plants do not produce antibodies. However, plants can correctly assemble functional antibody molecules encoded by mammalian antibody genes. Many plant diseases are caused by pathogen toxins. One such disease is the soybean sudden death syndrome (SDS). SDS is a serious disease caused by the fungal pathogen Fusarium virguliforme. The pathogen, however, has never been isolated from diseased foliar tissues. Thus, one or more toxins produced by the pathogen have been considered to cause foliar SDS. One of these possible toxins, FvTox1, was recently identified. We investigated whether expression of anti-FvTox1 single-chain variable-fragment (scFv) antibody in transgenic soybean can confer resistance to foliar SDS. We have created two scFv antibody genes, Anti-FvTox1-1 and Anti-FvTox1-2, encoding anti-FvTox1 scFv antibodies from RNAs of a hybridoma cell line that expresses mouse monoclonal anti-FvTox1 7E8 antibody. Both anti-FvTox1 scFv antibodies interacted with an antigenic site of FvTox1 that binds to mouse monoclonal anti-FvTox1 7E8 antibody. Binding of FvTox1 by the anti-FvTox1 scFv antibodies, expressed in either Escherichia coli or transgenic soybean roots, was initially verified on nitrocellulose membranes. Expression of anti-FvTox1-1 in stable transgenic soybean plants resulted in enhanced foliar SDS resistance compared with that in nontransgenic control plants. Our results suggest that i) FvTox1 is an important pathogenicity factor for foliar SDS development and ii) expression of scFv antibodies against pathogen toxins could be a suitable biotechnology approach for protecting crop plants from toxin-induced diseases.
First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on Sonchus asper in China
Authors: Pei D. , Xu X. , Feng Y. , Li C.
Published: March 2012

Sonchus asper is an exotic annual herb belonging to the Asteraceae family. Crude extracts of S. asper leaves have antiphlogistic and antibacterial properties. In May 2011, severe infection of powdery mildew was observed on S. asper in Henan Province, a central area of China. Symptoms began as small, nearly circular white spots that later enlarged and coalesced. As the disease progressed, white mycelia covered the entire plant, including the inflorescence. The voucher specimens are kept at the Key Laboratory of Plant-Microbe Interaction, Shangqiu Normal University. Conidiophores were erect, 108 to 220 × 10 to 12 μm, and composed of a cylindrical foot cell followed by two to three short cells. Nipple-shaped appressoria were formed on ectophytic mycelia. Conidia were hyaline and cylindrical, without distinct fibrosin bodies, and ranging from 29 to 42 × 19 to 24 μm. Long, unbranched germ tubes were formed from the ends of the conidia. These morphological characteristics suggested that the powdery mildew fungus is the anamorph of Golovinomyces cichoracearum (1,2). Chasmothecia were not observed in the collected samples. To confirm the identification, the internal transcribed spacer (ITS) region of the rDNA was amplified with ITS1 and ITS4 primers (4) and sequenced. The ITS sequence obtained was assigned Accession No. JQ010848 in GenBank, and had 99% similarity to two ITS sequences from different G. cichoracearum accessions (HM449077 and AY739111). The ITS sequence analysis further verified that the causal agent of the powdery mildew on S. asper was G. cichoracearum. Pathogenicity was confirmed by inoculating five healthy plants of S. asper with a conidial suspension (105 conidia/ml) from the infected plants, with five noninoculated plants serving as control. Inoculated plants developed the original powdery mildew symptoms after 10 days, whereas control plants remained healthy. G. cichoracearum (synonym Erysiphe cichoracearum) is a cosmopolitan powdery mildew fungus, parasitic on numerous plant species in the Asteraceae family. It was reported to be infecting S. asper in Bulgaria (3). To our knowledge, this is the first report of G. cichoracearum infections on S. asper in China. S. asper is one of the most important Chinese herbal medicines. The sudden appearance of powdery mildew caused by G. cichoracearum on this plant could result in substantial production loss of S. asper unless fungicide applications are employed.

References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) R. T. A. Cook and U. Braun. Mycol. Res. 113:616, 2009. (3) G. Negrean and C. M. Denchev. Mycologia Balcanica, 2004, 1:63. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.
Geographical Distribution and Survival ofIris yellow spot virusin Spiny Sowthistle,Sonchus asper, in Georgia
Authors: Nischwitz C. , Srinivasan R. , Sundaraj S. , Mullis S. W. , McInnes B. , Gitaitis R. D.
Published: March 2012

Iris yellow spot virus (IYSV) has occurred in Georgia since 2003. IYSV is transmitted by onion thrips, Thrips tabaci. During a weed survey in the Vidalia onion-growing zone (VOZ), spiny sowthistle (Sonchus asper) was identified as a host for IYSV. Spiny sowthistle is widespread in Georgia, and this presented an opportunity to study the natural spread of IYSV and assess its potential role in IYSV epidemiology. From 2007 to 2009, during the spring season, 2,011 sowthistle samples were collected from various counties within and outside the VOZ. The samples were tested for IYSV infection by enzyme-linked immunosorbent assay and confirmed by reverse-transcription polymerase chain reaction and sequencing. IYSV sequences from sowthistle were 98 to 99% identical to onion IYSV sequences from onion originated from Georgia. By the third year, IYSV-infected sowthistle plants were found in 79% of the counties in the VOZ and in 61% of the sampled counties in all directions, except to the east of the VOZ. Furthermore, thrips-mediated transmission assays confirmed that T. tabaci can efficiently transmit IYSV from onion to sowthistle. Sowthistle also supported T. tabaci survival and reproduction. These findings demonstrate that sowthistle plants can serve as an IYSV inoculum source and as a thrips reservoir.
A Rapid Resazurin-Based Microtiter Assay to Evaluate QoI Sensitivity for Alternaria alternata Isolates and Their Molecular Characterization
Authors: Vega Byron , Liberti Daniele , Harmon Philip F. , Dewdney Megan M.
Published: March 2012

Chemical management of Alternaria brown spot of citrus is based upon the timely application of site-specific fungicides, many of which are vulnerable to the development of fungicide resistance. A rapid microtiter bioassay based on the colorimetric changes of resazurin (RZ) dye was developed to evaluate the sensitivity of Alternaria alternata to quinone outside inhibitor (QoI) fungicides. Four liquid media (complete medium, minimal medium, potato dextrose broth, and yeast peptone dextrose broth), five conidia concentrations (from 101 to 105 conidia/ ml), and five RZ concentrations (10, 20, 30, 40, and 50 μM) were evaluated. Complete medium at 105 conidia/ml and 40 μM RZ were identified as optimal for measuring RZ reduction. The effective concentration of two QoI fungicides (azoxystrobin and pyraclostrobin) needed to reduce RZ by 50% (EC50) was calculated and compared with those obtained from conidia germination tests on fungicide-amended media. Concordant EC50 values were observed (R2 = 0.923; P < 0.0001) from both methods. Resistant phenotypes were further characterized by the partial sequencing of the cytochrome b gene. Genetic variability associated with the presence or absence of two introns was observed among isolates. The identified resistant isolates had the amino acid substitution G143A, typical of QoI resistance in other fungi.
RNAi of the circadian clock geneperioddisrupts the circadian rhythm but not the circatidal rhythm in the mangrove cricket
Authors: Takekata Hiroki , Matsuura Yu , Goto Shin G. , Satoh Aya , Numata Hideharu
Published: March 2012

The clock mechanism for circatidal rhythm has long been controversial, and its molecular basis is completely unknown. The mangrove cricket,Apteronemobius asahinai, shows two rhythms simultaneously in its locomotor activity: a circatidal rhythm producing active and inactive phases as well as a circadian rhythm modifying the activity intensity of circatidal active phases. The role of the clock geneperiod(per), one of the key components of the circadian clock in insects, was investigated in the circadian and circatidal rhythms ofA. asahinaiusing RNAi. After injection of double-stranded RNA ofper, most crickets did not show the circadian modulation of activity but the circatidal rhythm persisted without a significant difference in the period from controls. Thus,peris functionally involved in the circadian rhythm but plays no role, or a less important role, in the circatidal rhythm. We conclude that the circatidal rhythm inA. asahinaiis controlled by a circatidal clock whose molecular mechanism is different from that of the circadian clock.
Osteogenic differentiation and mineralization in fibre-reinforced tubular scaffolds: theoretical study and experimental evidences
Authors: Guarino Vincenzo , Urciuolo Francesco , Alvarez-Perez Marco A. , Mele Benedetto , Netti Paolo A. , Ambrosio Luigi
Published: March 2012

The development of composite scaffolds with well-organized architecture and multi-scale properties (i.e. porosity, degradation) represents a valid approach for achieving a tissue-engineered construct capable of reproducing the medium- and long-term
in vitro
behaviour of hierarchically complex tissues such as spongy bone. To date, the implementation of scaffold design strategies able to summarize optimal scaffold architecture as well as intrinsic mechanical, chemical and fluid transport properties still remains a challenging issue. In this study, poly
ɛ
-caprolactone/polylactid acid (PCL/PLA) tubular devices (fibres of PLA in a PCL matrix) obtained by phase inversion/salt leaching and filament winding techniques were proposed as cell instructive scaffold for bone osteogenesis. Continuous fibres embedded in the polymeric matrix drastically improved the mechanical response as confirmed by compression elastic moduli, which vary from 0.214 ± 0.065 to 1.174 ± 0.143 MPa depending on the relative fibre/matrix and polymer/solvent ratios. Moreover, computational fluid dynamic simulations demonstrated the ability of composite structure to transfer hydrodynamic forces during
in vitro
culture, thus indicating the optimal flow rate conditions that, case by case, enables specific cellular events—i.e. osteoblast differentiation from human mesenchymal stem cells (hMSCs), mineralization, etc. Hence, we demonstrate that the hMSC differentiation preferentially occurs in the case of higher perfusion rates—over 0.05 ml min
–1
—as confirmed by the expression of alkaline phosphate and osteocalcin markers. In particular, the highest osteopontin values and a massive mineral phase precipitation of bone-like phases detected in the case of intermediate flow rates (i.e. 0.05 ml min
–1
) allows us to identify the best condition to stimulate the bone extracellular matrix in-growth, in agreement with the hydrodynamic model prediction. All these results concur to prove the succesful use of tubular composite as temporary device for long bone treatment.
Microbial synthesis of core/shell gold/palladium nanoparticles for applications in green chemistry
Authors: Deplanche Kevin , Merroun Mohamed L. , Casadesus Merixtell , Tran Dung T. , Mikheenko Iryna P. , Bennett James A. , Zhu Ju , Jones Ian P. , Attard Gary A. , Wood J. , Selenska-Pobell Sonja , Macaskie Lynne E.
Published: March 2012

We report a novel biochemical method based on the sacrificial hydrogen strategy to synthesize bimetallic gold (Au)–palladium (Pd) nanoparticles (NPs) with a core/shell configuration. The ability of
Escherichia coli
cells supplied with H
2
as electron donor to rapidly precipitate Pd(II) ions from solution is used to promote the reduction of soluble Au(III). Pre-coating cells with Pd(0) (bioPd) dramatically accelerated Au(III) reduction, with the Au(III) reduction rate being dependent upon the initial Pd loading by mass on the cells. Following Au(III) addition, the bioPd–Au(III) mixture rapidly turned purple, indicating the formation of colloidal gold. Mapping of bio-NPs by energy dispersive X-ray microanalysis suggested Au-dense core regions and peripheral Pd but only Au was detected by X-ray diffraction (XRD) analysis. However, surface analysis of cleaned NPs by cyclic voltammetry revealed large Pd surface sites, suggesting, since XRD shows no crystalline Pd component, that layers of Pd atoms surround Au NPs. Characterization of the bimetallic particles using X-ray absorption spectroscopy confirmed the existence of Au-rich core and Pd-rich shell type bimetallic biogenic NPs. These showed comparable catalytic activity to chemical counterparts with respect to the oxidation of benzyl alcohol, in air, and at a low temperature (90°C).
Effects of the constraint's curvature on structural instability: tensile buckling and multiple bifurcations
Authors: Bigoni D. , Misseroni D. , Noselli G. , Zaccaria D.
Published: March 2012

Bifurcation of an elastic structure crucially depends on the curvature of the constraints against which the ends of the structure are prescribed to move, an effect that deserves more attention than it has received so far. In fact, we show theoretically and provide definitive experimental verification that an appropriate curvature of the constraint over which the end of a structure has to slide strongly affects buckling loads and can induce: (i) tensile buckling; (ii) decreasing- (softening), increasing- (hardening) or constant-load (null stiffness) postcritical behaviour; and (iii) multiple bifurcations, determining for instance two bifurcation loads (one tensile and one compressive) in a single-degree-of-freedom elastic system. We show how to design a constraint profile to obtain a desired postcritical behaviour and we provide the solution for the elastica constrained to slide along a circle on one end, representing the first example of an inflexional elastica developed from a buckling in tension. These results have important practical implications in the design of compliant mechanisms and may find applications in devices operating in quasi-static or dynamic conditions, even at the nanoscale.