bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions between Diatoms and Bacteria
Authors: Amin Shady A. , Parker Micaela S. , Armbrust E. Virginia
Published: August 2012

Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans.
Biogenesis of the Saccharomyces cerevisiae Pheromone
a
-Factor, from Yeast Mating to Human Disease
Authors: Michaelis Susan , Barrowman Jemima
Published: August 2012

The mating pheromone
a
-factor secreted by
Saccharomyces cerevisiae
is a farnesylated and carboxylmethylated peptide and is unusually hydrophobic compared to other extracellular signaling molecules. Mature
a
-factor is derived from a precursor with a C-terminal CAAX motif that directs a series of posttranslational reactions, including prenylation, endoproteolysis, and carboxylmethylation. Historically,
a
-factor has served as a valuable model for the discovery and functional analysis of CAAX-processing enzymes. In this review, we discuss the three modules comprising the
a
-factor biogenesis pathway: (i) the C-terminal CAAX-processing steps carried out by Ram1/Ram2, Ste24 or Rce1, and Ste14; (ii) two sequential N-terminal cleavage steps, mediated by Ste24 and Axl1; and (iii) export by a nonclassical mechanism, mediated by the ATP binding cassette (ABC) transporter Ste6. The small size and hydrophobicity of
a
-factor present both challenges and advantages for biochemical analysis, as discussed here. The enzymes involved in
a
-factor biogenesis are conserved from yeasts to mammals. Notably, studies of the zinc metalloprotease Ste24 in
S. cerevisiae
led to the discovery of its mammalian homolog ZMPSTE24, which cleaves the prenylated C-terminal tail of the nuclear scaffold protein lamin A. Mutations that alter ZMPSTE24 processing of lamin A in humans cause the premature-aging disease progeria and related progeroid disorders. Intriguingly, recent evidence suggests that the entire
a
-factor pathway, including all three biogenesis modules, may be used to produce a prenylated, secreted signaling molecule involved in germ cell migration in
Drosophila
. Thus, additional prenylated signaling molecules resembling
a
-factor, with as-yet-unknown roles in metazoan biology, may await discovery.
The Multiple Functions of TRBP, at the Hub of Cell Responses to Viruses, Stress, and Cancer
Authors: Daniels Sylvanne M. , Gatignol Anne
Published: August 2012

The TAR RNA binding protein (TRBP) has emerged as a key player in many cellular processes. First identified as a cellular protein that facilitates the replication of human immunodeficiency virus, TRBP has since been shown to inhibit the activation of protein kinase R (PKR), a protein involved in innate immune responses and the cellular response to stress. It also binds to the PKR activator PACT and regulates its function. TRBP also contributes to RNA interference as an integral part of the minimal RNA-induced silencing complex with Dicer and Argonaute proteins. Due to its multiple functions in the cell, TRBP is involved in oncogenesis when its sequence is mutated or its expression is deregulated. The depletion or overexpression of TRBP results in malignancy, suggesting that the balance of TRBP expression is key to normal cellular function. These studies show that TRBP is multifunctional and mediates cross talk between different pathways. Its activities at the molecular level impact the cellular function from normal development to cancer and the response to infections.
DNA Repair and Genome Maintenance in Bacillus subtilis
Authors: Lenhart Justin S. , Schroeder Jeremy W. , Walsh Brian W. , Simmons Lyle A.
Published: August 2012

From microbes to multicellular eukaryotic organisms, all cells contain pathways responsible for genome maintenance. DNA replication allows for the faithful duplication of the genome, whereas DNA repair pathways preserve DNA integrity in response to damage originating from endogenous and exogenous sources. The basic pathways important for DNA replication and repair are often conserved throughout biology. In bacteria, high-fidelity repair is balanced with low-fidelity repair and mutagenesis. Such a balance is important for maintaining viability while providing an opportunity for the advantageous selection of mutations when faced with a changing environment. Over the last decade, studies of DNA repair pathways in bacteria have demonstrated considerable differences between Gram-positive and Gram-negative organisms. Here we review and discuss the DNA repair, genome maintenance, and DNA damage checkpoint pathways of the Gram-positive bacterium
Bacillus subtilis.
We present their molecular mechanisms and compare the functions and regulation of several pathways with known information on other organisms. We also discuss DNA repair during different growth phases and the developmental program of sporulation. In summary, we present a review of the function, regulation, and molecular mechanisms of DNA repair and mutagenesis in Gram-positive bacteria, with a strong emphasis on
B. subtilis.
Sexually transmitted penile amoebiasis in Iran: a case series
Authors: Abdolrasouli Alireza , de Vries Henry J C , Hemmati Yahya , Roushan Azita , Hart Jason , Waugh Michael Anthony
Published: August 2012

Objectives

Four cases of penile amoebiasis (PA) presenting as genital ulceration seen among men who practiced unprotected insertive anal intercourse in Tehran are described.

Methods

PA was confirmed by observation of motile trophozoites ofEntamoeba histolyticafrom lesions examined by wet mount microscopy.

Results

Ulcers were solitary, painful, irregular, discharging and increasing in size. Three heterosexuals and one bisexual had practised insertive anal intercourse in the 2 weeks before diagnosis. Bilateral inguinal lymphadenitis occurred in one case. Direct examination of lesions was positive for the presence of amoebic trophozoites. Complete resolution occurred after treatment with oral metronidazole 800 mg three times daily for 7–10 days.

Conclusions

Clinicians need to be aware of cutaneous amoebiasis in sexually active men who practice unprotected insertive anal sex where intestinal amoebiasis is endemic. Wet mount microscopy is a rapid and useful diagnostic test.
External infections contribute minimally to HIV incidence among HIV sero-discordant couples in sub-Saharan Africa
Authors: Chemaitelly Hiam , Abu-Raddad Laith J
Published: August 2012

Objective

Recent randomised clinical trials among stable HIV sero-discordant couples (SDCs) in sub-Saharan Africa (SSA) have reported that about 20–30% of new HIV infections are acquired from external sexual partners, rather than transmitted from the infected to the uninfected partner within the couple. The aim of this study is to examine whether, and to what extent, these findings are generalisable to SDCs in the wider population in SSA.

Methods

A mathematical model was constructed to calculate the fraction of new HIV-1 infections among SDCs that are due to sources external to the couple. The model was parameterised using empirical and population-based data for 20 countries in SSA. Uncertainty and sensitivity analyses were also conducted.

Results

The contribution of external infections among SDCs was generally modest, but it varied widely across SSA. In low HIV prevalence countries (≤3.0%), it ranged from 0.6–2.9%. In intermediate prevalence countries (3.0–18.0%), it ranged from 4.9–11.7%. In Swaziland and Lesotho, the world's most-intense epidemics, sizable levels of 27.9% and 27.3% were found, respectively.

Conclusions

In most countries in SSA, nearly all HIV acquisitions by the uninfected partners in SDCs appear to be due to transmissions from the HIV infected partners in the SDCs. The contribution of externally acquired infections varies with HIV population prevalence, but rarely exceeds 10% in the majority of countries. Only in hyperendemic HIV epidemics the contribution of external infections is substantial and may reach the levels reported in recent randomised clinical trials involving SDCs.
Seed dynamics of two fire-dependent Geranium species in the boreal forest of southeastern Sweden
Authors: Risberg Lotta , Granström Anders
Published: August 2012

We analyzed critical life-history variables for two rare fire-dependent annual Geranium species in southern Sweden, which are today threatened because of effective fire suppression. At recently burned sites with abundant recruitment, seedlings occurred only where the humus layer had been completely removed by smoldering fire. Emergence depths ranged 1–6 cm in the mineral soil. Soil sampling at four sites revealed that in unburned soil Geranium seeds were located only in the mineral soil. Surprisingly, residual seeds were still present where fire had burned away the humus layer. An experiment showed that both species deposit seeds relatively evenly within a radius of 5–6 m, through ballistic dispersal. Repeated sampling in the field over a 2-year period after seed dispersal at one site indicated a low rate of seed depletion, corroborated by an indoor incubation of seeds. Our results show that successful management of these species depend on deep-burning prescribed fire, which can only result after severe drought. On the other hand, the seed bank is extremely long-lived, as viable seeds were present at a site last burned 200 years ago. This well-protected seed bank will likely buffer against both ill-timed fires and occasional failure in the recruiting seedling populations.
Salicylic acid analogues with biological activity may induce chilling tolerance of maize (Zea mays) seeds
Authors: Wang Yang , Hu Jin , Qin Guochen , Cui Huawei , Wang Qitian
Published: August 2012

One kind of biologically active salicylic acid (SA) analogue (acetylsalicylic acid, ASA) and two inactive compounds (4-aminosalicylic acid and 4-aminobenzoic acid), along with SA were chosen to evaluate their role in inducing chilling tolerance of two different chilling-tolerant maize ( Zea mays L.) inbred lines. These compounds were applied as seed treatments or as a hydroponic application. The results showed that four compounds had no significant effect on germination of maize seeds; however, SA or ASA soaking treatments significantly increased the root length, shoot height, and shoot and root dry weights of seedlings grown under chilling stress. Hydroponic applications of SA or ASA significantly alleviated the accumulation of malondialdehyde, hydrogen peroxide, and superoxide radicals in roots and leaves of both lines under chilling stress, and the applications also increased the photosynthetic pigments, including chlorophyll a, chlorophyll b, and carotenoids. However, 4-aminosalicylic acid and 4-aminobenzoic acid applications had no significant effect in ameliorating the growth inhibition of seedlings under chilling stress. This study showed that SA and ASA significantly induced the chilling tolerance of maize; however, 4-aminosalicylic acid and 4-aminobenzoic acid were not effective in inducing tolerance to chilling stress. The results suggest that only SA analogues with biological activity may have the ability to induce chilling tolerance of maize.
Nitrogen, phosphorus, and light effects on reproduction and fitness of wild rice
Authors: Sims Lee , Pastor John , Lee Tali , Dewey Brad
Published: August 2012

Plant fitness is typically correlated with total seed biomass or the number of seeds produced per plant, but the connection from seed production to seedlings the following year is seldom made. Seedling production in grasses, including wild rice ( Zizania palustris L.) is determined by the number of inflorescences produced, the number of seeds per inflorescence, the mean mass per seed, proportion of seeds that are filled, predation on seeds, and germination rates. Previous studies have shown that wild rice biomass production is limited primarily by nitrogen and secondarily by phosphorus and light. To test how nitrogen, phosphorus, and light modulate plant fitness, we evaluated the effects of nitrogen, phosphorus, and light on the above parameters. Nitrogen addition increased number of inflorescences, seeds per inflorescence, and mean seed mass, resulting in more seedlings produced, hence greater fitness, despite increased rice worm predation and lower germination rates of seeds compared to seeds from plants grown without nitrogen addition. Phosphorus additions and full sunlight also increased the number of seedlings per plant, mainly after nitrogen was added. Therefore, the maternal environment not only affects seed production but the number of seedlings that emerge the following year, especially with respect to nitrogen.
Flowering phenology and mimicry of the rattan Calamus castaneus (Arecaceae) in southern Thailand
Authors: Kidyoo Aroonrat Meekijjaroenroj , McKey Doyle
Published: August 2012

In the insect-pollinated dioecious rattan Calamus castaneus Griff., nectar and pollen rewards, together with visual and olfactory cues, attract insects to male flowers. Pistillate flowers are apparently rewardless. Here, we aimed to clarify the mechanisms assuring visitation and pollination of female flowers. We studied features of flowering phenology and floral biology that affect pollination success of plants of both sexes. The results show that C. castaneus features a striking system of mimicry, quite different from those studied previously in other dioecious plants. The population of C. castaneus was not significantly male biased and no intersexual difference in number of inflorescences per plant was detected. However, male plants began their blossoming earlier and flowered longer than female plants. There was thus an excess of male floral display. This excess should increase the frequency of insect-mediated transport of pollen from male to female plants. Furthermore, on female plants each pistillate flower is accompanied by a sterile staminate flower that appears to contribute to insect attraction. Quite similar in morphology and function to fertile staminate flowers, they produce similar visual and olfactory cues, but less rewards (nectar but no pollen). C. castaneus thus ensures pollination success by intersexual phenological differences and by floral mimicry.
Traditional Japanese Herbal (Kampo) Medicines and Treatment of Ocular Diseases: A Review
Authors: Hayasaka Seiji , Kodama Tatsuo , Ohira Akihiro
Published: August 2012

Herbal medicines have been used clinically in Eastern Asia, and traditional Japanese herbal (Kampo) formulas are approved as ethical drugs. The Kampo formulas are mixtures of the crude extracts of several herbs, each of which contains multiple components. Numerous investigators have reported that some herbal medicines are efficacious for treating several human diseases. We reviewed the literature on traditional herbal medicines and treatment of ocular diseases. Oral Orengedoku-to and Kakkon-to inhibit postoperative uveitis in humans. Oral Goshajinki-gan improved ocular surface disorders in patients with type 1 diabetes mellitus. Oral Hachimijio-gan increased retinal blood flow. Keishi-bukuryo-gan Sho might be associated with vitreoretinopathy in patients with type 2 diabetes mellitus. Oral Hachimijio-gan and Goshajinki-gan delayed lens opacification in rats and mice. Oral Sairei-to, Orengedoku-to, Senkanmeimoku-to, Scutellariae radix extract, Gardeniae fructus extract, topical Liguisticum wallichii rhizoma extract, and intravenous injection of tetramethylpyrazine, baicalin, baicalein, wogonin, and crocetin inhibited some forms of experimental uveitis in rabbits. Topical glycyrrhizinate improved allergic conjunctivitis in humans and rats. Oral crocetin improved eyestrain in humans. Oral berberine diminished experimental uveitis in rats. Baicalein, wogonin, berberine, and berberrubine inhibited in vitro expression of several cytokines in cultured retinal pigment epithelial cells. Some Kampo formulas are efficacious for treating several ocular diseases in humans and animals. Some herbal extracts and their components inhibit some forms of experimental uveitis.
Inhibition of Na+/K+-ATPase by Antcins, Unique Steroid-Like Compounds in Antrodia camphorate
Authors: Chung Tse-Yu , Li Feng-Yin , Chang Chi-I , Jinn Tzyy-Rong , Tzen Jason T. C.
Published: August 2012

The inhibition of Na+/K+ -ATPase by versatile steroid-like compounds contributes to the putative therapeutic effects of many Chinese medicinal cardiac products via the same molecular mechanism triggered by cardiac glycosides. Five major steroid-like compounds, antcin A, B, C, H, and K were isolated from Niuchangchih (Antrodia camphorata), a unique Taiwan mushroom, and all inhibited Na+/K+ -ATPase. Antcin A exhibited significantly higher inhibitory potency than the other four antcins, though weaker than ginsenoside Rh2 . In contrast, cortisone (an analogous steroid with anti-inflammatory effects stronger than antcin A) showed no detectable inhibitory potency. Molecular modeling has shown that antcins bind to Na+/K+ -ATPase with the steroidal skeleton structurally upside-down in comparison with ginsenoside Rh2 . The inhibitory potency of antcin A is attributed to steroidal hydrophobic interaction within the binding pocket and the formation of three hydrogen bonds between its carboxyl group and two cationic residues around the cavity entrance of Na+/K+ -ATPase. The presence of an additional carbonyl or hydroxyl group at C7 of the other four antcins leads to severe repulsion in the hydrophobic pocket, and thus significantly reduces inhibitory potency. It is proposed that antcin A is a bi-functional compound that exerts anti-inflammatory effects and that enhances blood circulation via two different molecular mechanisms.
Rubus coreanusInhibits Oxidized-LDL Uptake by Macrophages Through Regulation of JNK Activation
Authors: Bhandary Bidur , Lee Geum-Hwa , So Byung-Ok , Kim Sun-Young , Kim Min-Gul , Kwon Ji-Wung , Song Ji-Young , Lee Hee-Kwon , Kim Hyung-Ryong , Chae Soo-Wan , Chae Han-Jung
Published: August 2012

Oxidized low-density lipoprotein (oxLDL) contributes to atherosclerosis in part by being taken up into macrophages via scavenger receptors and leading to foam cell formation. Herbal compounds that have been used to treat blood stasis (a counterpart of atherosclerosis) for centuries include extracts of medicinal plants in the Rosaceae and Leguminosae families. In this study, we investigated the effect of the unripe Rubus coreanus (Korean black raspberry) fruit extract on oxLDL uptake by murine macrophage cells. In the presence of Rubus coreanus extract (RCE), Dil-labeled oxLDL uptake was inhibited in a dose-dependent manner. SP600125, a specific JNK inhibitor, inhibited the uptake of Dil-oxLDL into macrophages. RCE also inhibited JNK phosphorylation in a time- and dose-dependent manner in macrophages treated with oxLDL. These results indicate that among the mitogen-activated protein kinases, JNK phosphorylation is inhibited by RCE, which is likely the mechanism underlying the RCE-induced inhibition of oxLDL uptake by macrophages.
Longan Seed Extract Reduces Hyperuricemia via Modulating Urate Transporters and Suppressing Xanthine Oxidase Activity
Authors: Hou Chien-Wei , Lee Ying-Chung , Hung Hsiao-Fang , Fu Hua-Wen , Jeng Kee-Ching
Published: August 2012

Hyperuricemia causes gouty arthritis, kidney disease, heart disease, and other diseases. Xanthine oxidase (XOD) and urate transporters play important roles in urate homeostasis. Numerous plants have been identified as XOD inhibitors. Longan seeds are known to contain high levels of polyphenols such as corilagin, gallic acid and ellagic acid. We examined the effect of longan seed extract on XOD inhibition and urate transporters GLUT1 and GLUT9 using both in vitro and in vivo assays. The results showed that dried longan seed extract (LSE) and its active components inhibited XOD dose-dependently in vitro. LSE inhibited uric acid production and XOD activity in normal liver cells (clone-9 cells) and was not cytotoxic under the concentration of 200 μg/ml. For the in vivo study, Sprague-Dawley (SD) rats were given intraperitoneally for thirty minutes with or without allopurinol (a XOD inhibitor, 3.5 mg/kg) or LSE (80 mg/kg) and then injected intraperitioneally with 250 mg/kg of oxonic acid and 300 mg/kg of hypoxanthine intragastrically. LSE was able to reduce serum uric acid level and XOD activity in hyperuricemic rats. However, LSE or allopurinol did not inhibit the liver XOD activities. On the other hand, GLUT1 protein was suppressed in kidney and GLUT9 was induced in liver from experimental rats and LSE or allopurinol decreased GLUT9 but increased GLUT1 protein level in the liver and kidney, respectively. These results confirmed the claimed effect of longan seeds on gout and other complications and suggested that its urate reducing effect might be due to modulation of urate transporters and inhibition of circulating xanthine oxidase.
Viola yedoensisLiposoluble Fraction Ameliorates Lipopolysaccharide-Induced Acute Lung Injury in Mice
Authors: Li Wen , Xie Jun-Yun , Li Hong , Zhang Yun-Yi , Cao Jie , Cheng Zhi-Hong , Chen Dao-Feng
Published: August 2012

Viola yedoensis is a component of traditional Chinese herb medicine for inflammatory diseases. Chemical constituents of V. yedoensis have been shown to possess antibacterial, anti-HIV, and anticoagulant effects in experimental research; however, their anti-inflammatory properties remain to be demonstrated. In this study, a mouse model of lipopolysaccharide (LPS)-induced acute lung injury was used to investigate the effect of petroleum ether fraction of V. yedoensis (PEVY) on inflammation in vivo. After being shown to have anti-complementary activity in vitro, PEVY was orally administered to the mice at doses of 2, 4, and 8 mg/kg. Treatment with PEVY significantly decreased the wet-to-dry weight ratio of the lung, total cells, red blood cells, protein concentration, and myeloperoxidase activity in bronchoalveolar lavage fluid. PEVY markedly attenuated lung injury with improved lung morphology and reduced complement deposition. In addition, PEVY suppressed the expression of pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6. Taken together, PEVY protects the lung from acute injury, potentially via inhibiting the activation of the complement system and excessive production of proinflammatory mediators.
Evaluation of the Genotoxicity of Extracts of Houttuynia cordata Thunb.
Authors: Kang Chang Keun , Hah Dae Sik , Kim Chung Hui , Kim Euikyung , Kim Jong Shu
Published: August 2012

The present study was conducted to evaluate the activity of methanol extracts from Houttuynia cordata Thunb. (HC) in a reverse mutation assay in Salmonella typhimurium, and a chromosome aberration assay in the Chinese hamster ovary (CHO) cell line and to evaluate its effect on the occurrence of polychromatic erythrocytes in mice. In the reverse mutation assay using Salmonella typhimurium TA98, TA100, TA1535, and TA1537 and Escherichia coli WP2urvA-, methanol extracts of HC (5, 2.5, 1.25, 0.62, or 0.312 mg/plate) did not induce reverse mutations in the presence or absence of an S9 metabolic activation mixture. In the chromosome aberration test using CHO cells, methanol extracts (1.25, 2.5 or 5 μg/ml) caused a few incidences of structural and numerical aberrations, in both of absence or presence of an S9 metabolic activation mixture, but in comparison with the positive control group, these incidences were not significantly increased. In the mouse micronucleus test, no significant increases in the occurrence of micronucleated polychromatic erythrocytes were observed in male ICR mice that were orally administered methanol extracts of HC at doses of 2.0, 1.0, or 0.5 g/kg. From these results, we concluded that the methanol extracts of HC did not induce harmful effects on genes in bacteria, a mammalian cell system or in mouse bone marrow cells. Thus, HC's use for health promotion and/or a sick remedy for humans may be safe.
Anti-Inflammatory and Anti-Allergic Effect of Agaricus blazei Extract in Bone Marrow-Derived Mast Cells
Authors: Song Hyuk-Hwan , Chae Hee-Sung , Oh Sei-Ryang , Lee Hyeong-Kyu , Chin Young-Won
Published: August 2012

In this study, the anti-inflammatory and anti-allergic effects of the chloroform-soluble extract of Agaricus blazei in mouse bone marrow-derived mast cells (BMMCs) were investigated. The chloroform-soluble extract inhibited IL-6 production in PMA plus A23187-stimulated BMMCs, and down-regulated the phosphorylation of Akt. In addition, this extract demonstrated inhibition of the degranulation of β-hexosaminidase and the production of IL-6, prostaglandin D2 and leukotriene C4 in PMA plus A23187-induced BMMCs. In conclusion, the chloroform-soluble extract of Agaricus blazei exerted anti-inflammatory and anti-allergic activities mediated by influencing IL-6, prostaglandin D2, leukotriene C4, and the phosphorylation of Akt.
TEXTURE-ZERO MODEL FOR THE LEPTON MASS MATRICES
Authors: FERREIRA P. M. , LAVOURA L.
Published: August 2012

We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and Meμ = 0 (M is the effective light-neutrino Majorana mass matrix). We show that these predictions agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if m3 = 0, provided the Dirac phase δ is very close to maximal (±π/ 2). In the case of a normal neutrino mass spectrum, i.e. when m1 = 0, the agreement of our model with the data is imperfect — the reactor mixing angle θ13 is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.
SINGLE PRODUCTION OF FOURTH FAMILY SNEUTRINO VIA RPV COUPLINGS AT LINEAR COLLIDERS
Authors: ÇAKIR O. , KUDAY S. , ÇAKIR İ. T. , SULTANSOY S.
Published: August 2012

The single production of fourth family sneutrino [Formula: see text] via R-parity violating interactions in electron–positron collisions has been investigated. We study the decays of [Formula: see text] into different flavor dilepton e±μ∓ via R-parity violation. It is shown that R-parity violating couplings (λ411, λ412) down to 0.001 will be reachable at future linear colliders which would provide better accuracy comparing to the indirect measurements as complementary to the LHC results.
ANALYTICAL MECHANICS IN STOCHASTIC DYNAMICS: MOST PROBABLE PATH, LARGE-DEVIATION RATE FUNCTION AND HAMILTON–JACOBI EQUATION
Authors: GE HAO , QIAN HONG
Published: August 2012

Analytical (rational) mechanics is the mathematical structure of Newtonian deterministic dynamics developed by D'Alembert, Lagrange, Hamilton, Jacobi, and many other luminaries of applied mathematics. Diffusion as a stochastic process of an overdamped individual particle immersed in a fluid, initiated by Einstein, Smoluchowski, Langevin and Wiener, has no momentum since its path is nowhere differentiable. In this exposition, we illustrate how analytical mechanics arises in stochastic dynamics from a randomly perturbed ordinary differential equation dXt = b(Xt)dt+ϵdWt, where Wt is a Brownian motion. In the limit of vanishingly small ϵ, the solution to the stochastic differential equation other than [Formula: see text] are all rare events. However, conditioned on an occurrence of such an event, the most probable trajectory of the stochastic motion is the solution to Lagrangian mechanics with [Formula: see text] and Hamiltonian equations with H(p, q) = ‖p‖2+b(q)⋅p. Hamiltonian conservation law implies that the most probable trajectory for a "rare" event has a uniform "excess kinetic energy" along its path. Rare events can also be characterized by the principle of large deviations which expresses the probability density function for Xt as f(x, t) = e-u(x, t)/ϵ, where u(x, t) is called a large-deviation rate function which satisfies the corresponding Hamilton–Jacobi equation. An irreversible diffusion process with ∇×b≠0 corresponds to a Newtonian system with a Lorentz force [Formula: see text]. The connection between stochastic motion and analytical mechanics can be explored in terms of various techniques of applied mathematics, for example, singular perturbations, viscosity solutions and integrable systems.
SOLITON INTERACTIONS FOR A HIROTA–MAXWELL–BLOCH SYSTEM IN THE INHOMOGENEOUS ERBIUM-DOPED FIBER
Authors: WANG M. , TIAN B. , QI F.-H. , QIN B. , LIN Z.-Q.
Published: August 2012

In this paper, we consider a generalized Hirota–Maxwell–Bloch system with the higher-order dispersion and self-steepening effects, which describes the propagation of ultrashort optical pulse in the inhomogeneous erbium-doped fiber. Under certain coefficient constraints, N-soliton solutions are obtained through the Hirota method and symbolic computation. Soliton interactions are graphically presented and analyzed in the different fibers. Compared with the Hirota equation without the Maxwell–Bloch parts, the self-induced transparency effect caused by the doped erbium atoms is found to lead to the change of the soliton velocity and phase. In addition, the amplitudes and widths of solitons are respectively observed to decrease and increase in the dispersion-decreasing and dispersion-increasing fibers. Finally, we give the modulational instability condition through the linear stability analysis.
CONDUCTIVITY OF GAPPED GRAPHENE WITHIN RANDOM PHASE APPROXIMATION
Authors: ASHRAF SSZ
Published: August 2012

The gapped graphene is technologically more important as electronic devices made up of conventional semiconductors are based on the presence of a gap between the valence and conduction bands. In this paper, we report our analytical and numerical calculation of conductivity of gapped graphene on SiO 2 substrate and its variation with the governing parameters of carrier density, band gap, long range charge impurity scatterers, short range neutral defect scatterers, impurity distance from the graphene interface and potential strength of short range scattering centers. We find that the conductivity for unscreened potential decreases with increasing band gap but when screening is incorporated the trend is not only reversed but there is a sharp enhancement in its magnitude also. The sub linear behavior seen in conductivity in the case of gapless graphene at high carrier concentration due to enhanced scattering from the short range neutral defects is also observed for gapped graphene, and it is further observed that increasing the potential strength of the defect scatterers brings in the same behavior at relatively smaller carrier densities.
ACYCLIC ORIENTATIONS ON THE SIERPINSKI GASKET
Authors: CHANG SHU-CHIUAN
Published: August 2012

We study the number of acyclic orientations on the generalized two-dimensional Sierpinski gasket SG 2,b(n) at stage n with b equal to two and three, and determine the asymptotic behaviors. We also derive upper bounds for the asymptotic growth constants of SG 2,b and d-dimensional Sierpinski gasket SG d.
UNIVERSAL ALGORITHMS FOR PROBABILITY FORECASTING
Authors: ZHDANOV FEDOR , KALNISHKAN YURI
Published: August 2012

Multi-class classification is one of the most important tasks in machine learning. In this paper we consider two online multi-class classification problems: classification by a linear model and by a kernelized model. The quality of predictions is measured by the Brier loss function. We obtain two computationally efficient algorithms for these problems by applying the Aggregating Algorithms to certain pools of experts and prove theoretical guarantees on the losses of these algorithms. We kernelize one of the algorithms and prove theoretical guarantees on its loss. We perform experiments and compare our algorithms with logistic regression.
Perinatal exercise improves glucose homeostasis in adult offspring
Authors: Carter Lindsay G. , Lewis Kaitlyn N. , Wilkerson Donald C. , Tobia Christine M. , Ngo Tenlep Sara Y. , Shridas Preetha , Garcia-Cazarin Mary L. , Wolff Gretchen , Andrade Francisco H. , Charnigo Richard J. , Esser Karyn A. , Egan Josephine M. , de Cabo Rafael , Pearson Kevin J.
Published: August 2012

Emerging research has shown that subtle factors during pregnancy and gestation can influence long-term health in offspring. In an attempt to be proactive, we set out to explore whether a nonpharmacological intervention, perinatal exercise, might improve offspring health. Female mice were separated into sedentary or exercise cohorts, with the exercise cohort having voluntary access to a running wheel prior to mating and during pregnancy and nursing. Offspring were weaned, and analyses were performed on the mature offspring that did not have access to running wheels during any portion of their lives. Perinatal exercise caused improved glucose disposal following an oral glucose challenge in both female and male adult offspring ( P < 0.05 for both). Blood glucose concentrations were reduced to lower values in response to an intraperitoneal insulin tolerance test for both female and male adult offspring of parents with access to running wheels ( P < 0.05 and P < 0.01, respectively). Male offspring from exercised dams showed increased percent lean mass and decreased fat mass percent compared with male offspring from sedentary dams ( P < 0.01 for both), but these parameters were unchanged in female offspring. These data suggest that short-term maternal voluntary exercise prior to and during healthy pregnancy and nursing can enhance long-term glucose homeostasis in offspring.
Analysis of Subchannel and Rod Bundle PSBT Experiments with CATHARE 3
Authors: Valette M.
Published: August 2012

This paper presents the assessment of CATHARE 3 against PWR subchannel and rod bundle tests of the PSBT benchmark. Noticeable measurements were the following: void fraction in single subchannel and rod bundle, multiple liquid temperatures at subchannel exit in rod bundle, and DNB power and location in rod bundle. All these results were obtained both in steady and transient conditions. Void fraction values are satisfactory predicted by CATHARE 3 in single subchannels with the pipe module. More dispersed predictions of void values are obtained in rod bundles with the CATHARE 3 3D module at subchannel scale. Single-phase liquid mixing tests and DNB tests in rod bundle are also analyzed. After calibrating the mixing in liquid single phase with specific tests, DNB tests using void mixing give mitigated results, perhaps linked to inappropriate use of CHF lookup tables in such rod bundles with many spacers.
Remote-Time Division Multiplexing of Bending Sensors Using a Broadband Light Source
Authors: Bravo Mikel , López-Amo Manuel
Published: August 2012

This work experimentally demonstrates a remote sensing network which interrogates bending sensors using time-division multiplexing techniques and a broadband light source. The bending sensors are located 50 km away from the monitoring station. They are based on a simple tie displacement sensor and offer high-resolution measurements of displacement.
Cell Signals Influencing Hepatic Fibrosis
Authors: Cong Min , Iwaisako Keiko , Jiang Chunyan , Kisseleva Tatiana
Published: August 2012

Liver fibrosis is the result of the entire organism responding to a chronic injury. Every cell type in the liver contributes to the fibrosis. This paper first discusses key intracellular signaling pathways that are induced during liver fibrosis. The paper then examines the effects of these signaling pathways on the major cell types in the liver. This will provide insights into the molecular pathophysiology of liver fibrosis and should identify therapeutic targets.
Pulmonary Hypertension Secondary to COPD
Authors: Shujaat Adil , Bajwa Abubakr A. , Cury James D.
Published: August 2012

The development of pulmonary hypertension in COPD adversely affects survival and exercise capacity and is associated with an increased risk of severe acute exacerbations. Unfortunately not all patients with COPD who meet criteria for long term oxygen therapy benefit from it. Even in those who benefit from long term oxygen therapy, such therapy may reverse the elevated pulmonary artery pressure but cannot normalize it. Moreover, the recent discovery of the key roles of endothelial dysfunction and inflammation in the pathogenesis of PH provides the rationale for considering specific pulmonary vasodilators that also possess antiproliferative properties and statins.
PGC-1αInduction in Pulmonary Arterial Hypertension
Authors: Mata Manuel , Sarrion Irene , Milian Lara , Juan Gustavo , Ramon Mercedes , Naufal Dolores , Gil Juan , Ridocci F. , Fabregat-Andrés O. , Cortijo Julio
Published: August 2012

Idiopathic Pulmonary arterial hypertension (IPAH) is characterized by the obstructive remodelling of pulmonary arteries, and a progressive elevation in pulmonary arterial pressure (PAP) with subsequent right-sided heart failure and dead. Hypoxia induces the expression of peroxisome proliferator activated receptorγcoactivator-1α(PGC-1α) which regulates oxidative metabolism and mitochondrial biogenesis. We have analysed the expression of PGC-1α, cytochrome C (CYTC), superoxide dismutase (SOD), the total antioxidant status (TAS) and the activity of glutathione peroxidase (GPX) in blood samples of IPAH patients. Expression of PGC-1αwas detected in IPAH patients but not in healthy volunteers. The mRNA levels of SOD were lower in IPAH patients compared to controls (3.93 ± 0.89 fold change). TAS and GPX activity were lower too in patients compared to healthy donors, (0.13 ± 0.027 versus 0.484 ± 0.048 mM and 56.034 ± 10.37 versus 165.46 ± 11.38 nmol/min/mL, resp.). We found a negative correlation between expression levels of PGC-1αand age, PAP and PVR, as well as a positive correlation with CI, PaO2, mRNA levels of CYTC and SOD, TAS and GPX activity. These results taken together are indicative of the possible role of PGC-1αas a potential biomarker of the progression of IPAH.
Improving Adherence to Guidelines for the Diagnosis and Management of Pelvic Inflammatory Disease: A Systematic Review
Authors: Liu Bette , Donovan Basil , Hocking Jane S. , Knox Janet , Silver Bronwyn , Guy Rebecca
Published: August 2012

Background.Evidence suggests adherence to clinical guidelines for pelvic inflammatory disease (PID) diagnosis and management is suboptimal. We systematically reviewed the literature for studies describing strategies to improve the adherence to PID clinical guidelines.Methods.The databases MEDLINE and EMBASE, and reference lists of review articles were searched from January 2000 to April 2012. Only studies with a control group were included.Results.An interrupted time-series study and two randomised controlled trials (RCTs) were included. The interrupted time-series found that following a multifaceted patient and practitioner intervention (practice protocol, provision of antibiotics on-site, written instructions for patients, and active followup), more patients received the recommended antibiotics and attended for followup. One RCT found a patient video on PID self-care did not improve medication compliance and followup. Another RCT found an abbreviated PID treatment guideline for health-practitioners improved their management of PID in hypothetical case scenarios but not their diagnosis of PID.Conclusion.There is limited research on what strategies can improve practitioner and patient adherence to PID diagnosis and management guidelines. Interventions that make managing PID more convenient, such as summary guidelines and provision of treatment on-site, appear to lead to better adherence but further empirical evidence is necessary.
Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes
Authors: Ma Chih Ming , Shen Yung Shuen , Lin Po Hsiang
Published: August 2012

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.
Hepatoprotective Activity ofElephantopus scaberon Alcohol-Induced Liver Damage in Mice
Authors: Ho Wan Yong , Yeap Swee Keong , Ho Chai Ling , Abdul Rahim Raha , Alitheen Noorjahan Banu
Published: August 2012

Elephantopus scaberhas been traditionally used as liver tonic. However, the protective effect ofE. scaberon ethanol-induced liver damage is still unclear. In this study, we have compared thein vivohepatoprotective effect ofE. scaberwithPhyllanthus nirurion the ethanol-induced liver damage in mice. The total phenolic and total flavanoid content ofE. scaberethanol extract were determined in this study. Accelerating serum biochemical profiles (including AST, ALT, ALP, triglyceride, and total bilirubin) associated with fat drop and necrotic body in the liver section were observed in the mice treated with ethanol. Low concentration ofE. scaberwas able to reduce serum biochemical profiles and the fat accumulation in the liver. Furthermore, high concentration ofE. scaberand positive controlP. niruriwere able to revert the liver damage, which is comparable to the normal control. Added to this,E. scaberdid not possess any oral acute toxicity on mice. These results suggest the potential effect of this extract as a hepatoprotective agent towards-ethanol induced liver damage without any oral acute toxicity effect. These activities might be contributed, or at least in part, by its high total phenolic and flavonoid contents.
Geophysical Surveys at Khirbat Faynan, an Ancient Mound Site in Southern Jordan
Authors: Novo Alexandre , Vincent Matthew L. , Levy Thomas E.
Published: August 2012

Faynan in Jordan contains the largest copper ore resource zone in the southern Levant (Israel, Jordan, Palestinian territories, Lebanon, Syria, and the Sinai Peninsula). Located 50 km southeast of the Dead Sea, it is home to one of the world’s best-preserved ancient mining and metallurgy districts encompassing an area of ca. 400 km2. During the past three decades, archaeologists have carried out numerous excavations and surveys recording hundreds of mines and sites related to metallurgical activities that span the past 10 millennia. Khirbat Faynan (Biblical Punon), is situated in the main Faynan Valley and is the largest (ca. 15 ha) settlement site in the region and has remained unexcavated until 2011. As Jordan’s most southern mound site with indications of widespread ancient architecture, we employed a suite of noninvasive geophysical survey methods to identify areas suitable for excavation. Earlier geophysical surveys were carried out in the Faynan region by our team in the late 1990s when only EMI (electromagnetic induction) proved successful, but with relatively poor resolution. As reported here, by 2011, improvements in data processing software and 3D ERT (electrical resistivity tomography) sampling protocols made it possible to greatly improve the application of noninvasive geophysical surveying in this hyperarid zone.
Pulmonary Arterial Hypertension in Adult-Onset Still’s Disease: Rapid Response to Anakinra
Authors: Campos Marc , Schiopu Elena
Published: August 2012

Adult-onset Still’s disease (AOSD) is a rare inflammatory condition characterized by spiking quotidian fever, rash, chronic arthralgia, leukocytosis, and occasional pulmonary involvement such as pleural effusion and transient pulmonary infiltrates. Pulmonary arterial hypertension (PAH) is a rare pulmonary complication of AOSD, and we are aware of only 5 cases reported in the literature. We report the case of a 27-year-old woman of Middle Eastern descent, with a 7-year history of AOSD, who developed severe pulmonary arterial hypertension (PAH). After unsuccessful exposure to various immunosuppressive regimens, shortly following the initiation of anakinra, an interleukin-1 (IL-1) receptor antagonist, her disease became quiescent and the PAH resolved. With this case report, we hope to show that anakinra, either by virtue of controlling the overall inflammation in AOSD, or by direct effect on the pulmonary microangiopathy, can improve severe PAH.
Elevated Serum Carboxymethyl-Lysine, an Advanced Glycation End Product, Predicts Severe Walking Disability in Older Women: The Women's Health and Aging Study I
Authors: Sun Kai , Semba Richard D. , Fried Linda P. , Schaumberg Debra A. , Ferrucci Luigi , Varadhan Ravi
Published: August 2012

Advanced glycation end products (AGEs) have been implicated in the pathogenesis of sarcopenia. Our aim was to characterize the relationship between serum carboxymethyl-lysine (CML), a major circulating AGE, and incident severe walking disability (inability to walk or walking speed<0.4 m/sec) over 30 months of followup in 394 moderately to severely disabled women,≥65years, living in the community in Baltimore, Maryland (the Women’s Health and Aging Study I). During followup, 154 (26.4%) women developed severe walking disability, and 23 women died. Women in the highest quartile of serum CML had increased risk of developing of severe walking disability in a multivariate Cox proportional hazards model, adjusting for age and other potential confounders. Women with elevated serum CML are at an increased risk of developing severe walking disability. AGEs are a potentially modifiable risk factor. Further work is needed to establish a causal relationship between AGEs and walking disability.
The Numerical Solution of Problems in Calculus of Variation Using B‐Spline Collocation Method
Authors: Zarebnia M. , Birjandi M.
Published: August 2012

A B‐spline collocation method is developed for solving boundary value problems which arise from the problems of calculus of variations. Some properties of the B‐spline procedure required for subsequent development are given, and they are utilized to reduce the solution computation of boundary value problems to some algebraic equations. The method is applied to a few test examples to illustrate the accuracy and the implementation of the method.