bluuebunny/crossref_metadata_2025 huggingface dataset:
History, Advances, and Challenges in Liquid Flow and Flow Boiling Heat Transfer in Microchannels: A Critical Review
Authors: Kandlikar Satish G.
Published: January 2012

As the scale of devices becomes small, thermal control and heat dissipation from these devices can be effectively accomplished through the implementation of microchannel passages. The small passages provide a high surface area to volume ratio that enables higher heat transfer rates. High performance microchannel heat exchangers are also attractive in applications where space and/or weight constraints dictate the size of a heat exchanger or where performance enhancement is desired. This survey article provides a historical perspective of the progress made in understanding the underlying mechanisms in single-phase liquid flow and two-phase flow boiling processes and their use in high heat flux removal applications. Future research directions for (i) further enhancing the single-phase heat transfer performance and (ii) enabling practical implementation of flow boiling in microchannel heat exchangers are outlined.
The Role of Entropy Generation in Momentum and Heat Transfer
Authors: Herwig Heinz
Published: January 2012

Entropy generation in a velocity and temperature field is shown to be very significant in momentum and heat transfer problems. After the determination of this postprocessing quantity, many details about the physics of a problem are available. This second law analysis (SLA) is a tool for conceptual considerations, for the determination of losses, both in the velocity and the temperature field, and it helps to assess complex convective heat transfer processes. These three aspects in conjunction with entropy generation are discussed in detail and illustrated by several examples.
Self-aligned patterning on a flexible substrate using a dual-tone, thermally activated photoresist
Authors: Jen Wei-Lun K. , Rawlings Brandon M. , Strahan Jeffrey R. , Hellebusch Daniel J. , Durand William J. , Grant Willson C.
Published: January 2012

The fabrication of electronic devices on flexible substrates represents an opportunity for the development of flexible display technologies, large area devices, and roll-to-roll manufacturing processes. Traditional photolithography encounters alignment and overlay limitations when applied to flexible substrates. One solution to the overlay challenges is imaging of two device layers in a single lithographic exposure. To enable the simultaneous patterning of two device layers, a new photoresist system was developed. Prior work on dual-tone photoresists introduced formulations capable of storing two independent images, but the reported systems are incompatible with the reactive ion etch processes commonly used today. This paper describes a dual-tone photoresist system that maintains the ability to store two independent latent images, distinguished by the incident exposure light wavelength, simultaneously remaining compatible with reactive ion etch image transfer processes.
Tuning the Response to Pathogens
Authors: Gough Nancy R.
Published: January 2012

Brassinosteroid signaling can either enhance or attenuate the plant’s response to infection.
Discordant Temporal Evolution of
Pfcrt
and
Pfmdr1
Genotypes and Plasmodium falciparum In Vitro Drug Susceptibility to 4-Aminoquinolines after Drug Policy Change in French Guiana
Authors: Legrand Eric , Yrinesi Joséphine , Ekala Marie-Thérèse , Péneau Julie , Volney Béatrice , Berger Franck , Bouchier Christiane , Bertani Stéphane , Musset Lise , Meynard Jean-Baptiste , Mercereau-Puijalon Odile
Published: January 2012

Analysis of the evolution of drug target genes under changing drug policy is needed to assist monitoring of
Plasmodium falciparum
drug resistance in the field. Here we genotype
Pfcrt
and
Pfdmr1
of 700 isolates collected in French Guiana from 2000 (5 years after withdrawal of chloroquine) to 2008, i.e., the period when the artemether-lumefantrine combination was progressively introduced and mefloquine was abandoned. Gene sequencing showed fixation of the 7G8-type
Pfcrt
SMVNT resistance haplotype and near fixation of the NYCDY
Pfdmr1
haplotype.
Pfdmr1
gene copy number correlated with 50% inhibitory concentrations of mefloquine and halofantrine (
r
= 0.64 and 0.47, respectively,
n
= 547); its temporal changes paralleled changes in
in vitro
mefloquine susceptibility. However, the molecular parameters studied did not account for the regained
in vitro
susceptibility to chloroquine and showed a poor correlation with susceptibility to artemether, lumefantrine, or quinine. Identification of novel markers of resistance to these antimalarials is needed in this South American area.
Hydrolysis Spectrum Extension of CMY-2-Like β-Lactamases Resulting from Structural Alteration in the Y-X-N Loop
Authors: Dahyot Sandrine , Mammeri Hedi
Published: January 2012

The
Citrobacter freundii
isolate CHA, which was responsible for postoperative peritonitis after 10 days of cefepime therapy, displayed a phenotype of resistance consistent with extended-spectrum AmpC (ESAC) β-lactamase. The chromosome-borne
bla
AmpC-CHA
gene was amplified and sequenced, revealing five amino acid substitutions, I125V, R148H, Q196H, V305A, and V348A, in the product compared to the sequence of native AmpC. A cloning experiment yielded the
Escherichia coli
TOP10(pAmpC-CHA) strain, which was resistant to all extended-spectrum cephalosporins (ESCs), including cefepime. To ascertain whether the R148H substitution accounted for the hydrolysis spectrum extension, it was reverted by site-directed mutagenesis. The resulting
E. coli
TOP10(pAmpC-CHA-H148R) strain was fully susceptible to cefepime, thus confirming that the Arg-148 replacement was mandatory for substrate profile enlargement. To further characterize the phenotypical and biochemical effects induced by the R148H change, it was introduced by site-directed mutagenesis into the CMY-2 β-lactamase, which is structurally related to the chromosome-borne cephalosporinase of
C. freundii
. The CMY-2-R148H variant conferred increased MICs of ESCs, whereas those of carbapenems were unchanged even in a porin-deficient
E. coli
strain. Moreover, it exhibited increased catalytic efficiency (
k
cat
/

K
m

) toward ceftazidime (100-fold) due to an enhanced hydrolysis rate (
k
cat
), whereas the enzymatic parameters toward imipenem were unchanged. The structural analysis of the AmpC variant showed that the R148H replacement occurred in the loop containing the Y-X-N motif, which is the counterpart of the SDN loop in class A β-lactamases. This study shows that the Y-X-N loop is a novel hot spot for mutations accounting for hydrolysis spectrum extension in CMY-2-type enzymes.
Antimicrobial Activity of the Investigational Pleuromutilin Compound BC-3781 Tested against Gram-Positive Organisms Commonly Associated with Acute Bacterial Skin and Skin Structure Infections
Authors: Sader Helio S. , Biedenbach Douglas J. , Paukner Susanne , Ivezic-Schoenfeld Zrinka , Jones Ronald N.
Published: January 2012

BC-3781 is a novel semisynthetic pleuromutilin antimicrobial agent developed as an intravenous and oral therapy for acute bacterial skin and skin structure infections (ABSSSI) and respiratory tract infections (RTI). BC-3781 and comparator agents were tested by the broth microdilution method against 1,893 clinical Gram-positive organisms predominantly causing ABSSSI. BC-3781 exhibited potent activity against methicillin-resistant
Staphylococcus aureus
(MIC
50/90
, 0.12/0.25 μg/ml), coagulase-negative staphylococci (MIC
50/90
, 0.06/0.12 μg/ml), β-hemolytic streptococci (MIC
50/90
, 0.03/0.06 μg/ml), viridans group streptococci (MIC
50/90
, 0.12/0.5 μg/ml), and
Enterococcus faecium
(including vancomycin-nonsusceptible strains) (MIC
50/90
, 0.12/2 μg/ml). Compared with other antibiotics in use for the treatment of ABSSSI, BC-3781 displayed the lowest MICs and only a minimal potential for cross-resistance with other antimicrobial classes.
A Novel Membrane Protein, VanJ, Conferring Resistance to Teicoplanin
Authors: Novotna Gabriela , Hill Chris , Vincent Karen , Liu Chang , Hong Hee-Jeon
Published: January 2012

Bacterial resistance to the glycopeptide antibiotic teicoplanin shows some important differences from the closely related compound vancomycin. They are currently poorly understood but may reflect significant differences in the mode of action of each antibiotic.
Streptomyces coelicolor
possesses a
vanRSJKHAX
gene cluster that when expressed confers resistance to both vancomycin and teicoplanin. The resistance to vancomycin is mediated by the enzymes encoded by
vanKHAX
, but not by
vanJ. vanHAX
effect a reprogramming of peptidoglycan biosynthesis, which is considered to be generic, conferring resistance to all glycopeptide antibiotics. Here, we show that
vanKHAX
are not in fact required for teicoplanin resistance in
S. coelicolor
, which instead is mediated solely by
vanJ. vanJ
is shown to encode a membrane protein oriented with its C-terminal active site exposed to the extracytoplasmic space. VanJ also confers resistance to the teicoplanin-like antibiotics ristocetin and A47934 and to a broad range of semisynthetic teicoplanin derivatives, but not generally to antibiotics or semisynthetic derivatives with vancomycin-like structures.
vanJ
homologues are found ubiquitously in streptomycetes and include
staP
from the
Streptomyces toyocaensis
A47934 biosynthetic gene cluster. While overexpression of
staP
also conferred resistance to teicoplanin, similar expression of other
vanJ
homologues (SCO2255, SCO7017, and SAV5946) did not. The
vanJ
and
staP
orthologues, therefore, appear to represent a subset of a larger protein family whose members have acquired specialist roles in antibiotic resistance. Future characterization of the divergent enzymatic activity within this new family will contribute to defining the molecular mechanisms important for teicoplanin activity and resistance.
Mechanisms of Action of Escapin, a Bactericidal Agent in the Ink Secretion of the Sea Hare Aplysia californica: Rapid and Long-Lasting DNA Condensation and Involvement of the OxyR-Regulated Oxidative Stress Pathway
Authors: Ko Ko-Chun , Tai Phang C. , Derby Charles D.
Published: January 2012

The marine snail
Aplysia californica
produces escapin, an
l
-amino acid oxidase, in its defensive ink. Escapin uses
l
-lysine to produce diverse products called escapin intermediate products of
l
-lysine (EIP-K), including α-amino-ε-caproic acid, Δ
1
-piperidine-2-carboxylic acid, and Δ
2
-piperidine-2-carboxylic acid. EIP-K and H
2
O
2
together, but neither alone, is a powerful bactericide. Here, we report bactericidal mechanisms of escapin products on
Escherichia coli
. We show that EIP-K and H
2
O
2
together cause rapid and long-lasting DNA condensation: 2-min treatment causes significant DNA condensation and killing, and 10-min treatment causes maximal effect, lasting at least 70 h. We isolated two mutants resistant to EIP-K plus H
2
O
2
, both having a single missense mutation in the oxidation regulatory gene,
oxyR
. A complementation assay showed that the mutated gene,
oxyR
(
A233V
), renders resistance to EIP-K plus H
2
O
2
, and a gene dosage effect leads to reduction of resistance for strains carrying wild-type
oxyR
. Temperature stress with EIP-K does not produce the bactericidal effect, suggesting the effect is due to a specific response to oxidative stress. The null mutant for any single DNA-binding protein—Dps, H-NS, Hup, Him, or MukB—was not resistant to EIP-K plus H
2
O
2
, suggesting that no single DNA-binding protein is necessary to mediate this bactericidal effect, but allowing for the possibility that EIP-K plus H
2
O
2
could function through a combination of DNA-binding proteins. The bactericidal effect of EIP-K plus H
2
O
2
was eliminated by the ferrous ion chelator 1,10-phenanthroline, and it was reduced by the hydroxyl radical scavenger thiourea, suggesting hydroxyl radicals mediate the effects of EIP-K plus H
2
O
2
.
A Double, Long Polar Fimbria Mutant of Escherichia coli O157:H7 Expresses Curli and Exhibits Reduced
In Vivo
Colonization
Authors: Lloyd Sonja J. , Ritchie Jennifer M. , Rojas-Lopez Maricarmen , Blumentritt Carla A. , Popov Vsevolod L. , Greenwich Jennifer L. , Waldor Matthew K. , Torres Alfredo G.
Published: January 2012

Escherichia coli
O157:H7 causes food and waterborne enteric infections that can result in hemorrhagic colitis and life-threatening hemolytic uremic syndrome. Intimate adherence of the bacteria to intestinal epithelial cells is mediated by intimin, but
E. coli
O157:H7 also possess several other putative adhesins, including curli and two operons that encode long polar fimbriae (Lpf). To assess the importance of Lpf for intestinal colonization, we performed competition experiments between
E. coli
O157:H7 and an isogenic Δ
lpfA1
Δ
lpfA2
double mutant in the infant rabbit model. The mutant was outcompeted in the ileum, cecum, and midcolon, suggesting that Lpf contributes to intestinal colonization. In contrast, the Δ
lpfA1
Δ
lpfA2
mutant showed increased adherence to colonic epithelial cells
in vitro
. Transmission electron microscopy revealed curli-like structures on the surface of the Δ
lpfA1
Δ
lpfA2
mutant, and the presence of curli was confirmed by Congo red binding, immunogold-labeling electron microscopy, immunoblotting, and quantitative real-time reverse transcription-PCR (qRT-PCR) measuring
csgA
expression. However, deletion of
csgA
, which encodes the major curli subunit, does not appear to affect intestinal colonization. In addition to suggesting that Lpf can contribute to EHEC intestinal colonization, our observations indicate that the regulatory pathways governing the expression of Lpf and curli are interdependent.
Some historical chemistry: The structures of dieucarvelones A, B and C and the structure of α-amyrilene
Authors: Huneck Siegfried , Connolly Joseph D. , Farrugia Louis
Published: January 2012

Spectroscopic examination of some historical samples from the terpene collection of Prof. H. Wienhaus resulted in the structure elucidation of dieucarvelones A, B and C, products of treatment of eucarvone with zinc in alkali and in confirmation of the structure of α-amyrilene, a rearrangement product of α-amyrin. The relative stereochemistry of dieucarvelones A and C was established by X-ray crystallographic analyses.
Current treatment strategies for epistaxis: a multidisciplinary approach
Authors: Shukla Pratik A , Chan Norman , Duffis Ennis J , Eloy Jean Anderson , Prestigiacomo Charles Joseph , Gandhi Chirag D
Published: January 2012

Epistaxis is a common clinical complaint with a spectrum of severity ranging from spontaneous cessation to unrelenting, life threatening hemorrhage requiring surgical treatment. Both otolaryngologic and neurointerventional techniques are discussed to provide a comprehensive paradigm to treat patients with epistaxis. An exhaustive review of the anatomic basis for the two main subtypes of epistaxis is provided as well as a graduated approach to appropriate clinical management.
Energy acquisition and allocation patterns of lake whitefish (Coregonus clupeaformis) are modified when dreissenids are present
Authors: Rennie Michael D. , Johnson Timothy B. , Sprules W. Gary
Published: January 2012

We evaluated the effects of dreissenid-induced food web changes on rates of lake whitefish ( Coregonus clupeaformis ) energy acquisition and allocation in North American populations. We used mass-balance models of lake whitefish growth and methylmercury accumulation in 17 populations with and without dreissenids present to estimate and contrast rates of activity (ACT), consumption (C) and conversion efficiency (V). Historical estimates were also generated for a single lake whitefish population during dreissenid establishment. Bioenergetic estimates from both scenarios were compared with densities of Diporeia , a historically important diet component of lake whitefish. Mean lake whitefish ACT and C estimates in populations with dreissenids were significantly greater: 1.3–2 times those of populations without dreissenids. Conversion efficiencies scaled positively and significantly, while C and ACT varied negatively and significantly with Diporeia abundance. Our results suggest that changes in lake whitefish activity may affect density estimates — and ultimately sustainable management quotas — for this species. Our results also show that reported declines in lake whitefish individual growth rates in South Bay, Lake Huron, can be explained by increased activity rates due to increased foraging activity in an energetically depleted prey community.
Different organochlorine contaminant profiles in groups of flounders (Platichthys flesus) from sampling locations around Denmark
Authors: Vorkamp Katrin , Svendsen Tore Christian , Rønsholdt Bent , Larsen Martin Mørk
Published: January 2012

Flounders ( Platichthys flesus ) from the waters around Denmark were analysed for their organochlorine (OC) profile to study whether fish from the same genetic population could be separated into characteristic subpopulations, based on their feeding grounds. The chemical analysis of fish liver provided a data set of 16 OC compounds in 94 samples from 2004 to 2006. Except for hexachlorocyclohexane, OC compounds were intercorrelated, indicating similar environmental fate and bioaccumulation. OC profiles are less affected than absolute concentrations by potentially confounding biological factors and thus more suitable for studies of intrapopulation differences in relation to feeding grounds. Principal component analysis grouped the samples according to locations. All but three of the 94 samples could be reclassified. Samples from the same and additional locations collected in 2003 provided validation, with only few misclassifications. This statistical separation likely reflects location-specific pollutant patterns in sediments and biota, even on the relatively small scale of this study. Thus, despite the lack of genetic differences, characteristic subpopulations of flounders could be identified with separate feeding grounds. OC profiles have been used increasingly to distinguish stocks.
Limited effects of stocked trout on littoral invertebrates in boreal foothills lakes
Authors: Nasmith Leslie E. , Tonn William M. , Paszkowski Cynthia A. , Scrimgeour Garry J.
Published: January 2012

Stocking lakes with trout for the purposes of recreational angling is a management strategy that introduces a new predator into these systems and thus deserves careful scrutiny. To assess the impact of non-native trout on littoral invertebrates in naturally fish-bearing lakes in the boreal foothills of Alberta, Canada, we compared their community composition, abundance, and size structure in stocked (n = 5) and unstocked (n = 6) lakes over a 2-year period. We detected no clear negative effects of introduced trout on invertebrate community composition and only few taxa-specific examples of decreased or increased invertebrate abundance. Furthermore, predation by trout had inconsistent direct effects on the size structure of invertebrate populations. Indirect effects were suggested by increased abundances and sizes of some invertebrate taxa in stocked lakes and might also contribute to the limited overall differences that we observed. We propose that net effects of stocked trout on littoral invertebrates are influenced by key characteristics of receiving ecosystems. In our boreal foothills lakes, dense macrophyte cover in warm littoral zones, high productivity, abundant forage fish, and limited densities of trout all likely combine to allow littoral invertebrate communities to withstand the impact of introduced trout with minimal effects.
Fine mapping of the yellow seed locus in Brassica juncea L.
Authors: Huang Zhen , Ban Yuanyuan , Yang Li , Zhang Yu , Li Huiqiang , Xiao Enshi , Xu Aixia , Zhang Denghui
Published: January 2012

The yellow mustard plant in Northern Shaanxi is a precious germplasm, and the yellow seed trait is controlled by a single recessive gene. In this report, amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) techniques were used to identify markers linked to the brown seed locus in an F2 population consisting of 1258 plants. After screening 256 AFLP primer combinations and 456 pairs of SSR primers, we found 14 AFLP and 2 SSR markers that were closely linked to the brown seed locus. Among these markers, the SSR marker CB1022 showed codominant inheritance. By integrating markers previously found to be linked to the brown seed locus into the genetic map of the F2 population, 23 markers were linked to the brown seed locus. The two closest markers, EA02MC08 and P03MC08, were located on either side of the brown seed locus at a distance of 0.3 and 0.5 cM, respectively. To use the markers for the breeding of yellow-seeded mustard plants, two AFLP markers (EA06MC11 and EA08MC13) were converted into sequence-characterized amplified region (SCAR) markers, SC1 and SC2, with the latter as the codominant marker. The two SSR markers were subsequently mapped to the A9/N9 linkage group of Brassica napus L. by comparing common SSR markers with the published genetic map of B. napus. A BLAST analysis indicated that the sequences of seven markers showed good colinearity with those of Arabidopsis chromosome 3 and that the homolog of the brown seed locus might exist between At3g14120 and At3g29615 on this same chromosome. To develop closer markers, we could make use of the sequence information of this region to design primers for future studies. Regardless, the close markers obtained in the present study will lay a solid foundation for cloning the yellow seed gene using a map-based cloning strategy.
Evidence that the spindle assembly checkpoint does not regulate APCFzyactivity inDrosophilafemale meiosis
Authors: Batiha Osamah , Swan Andrew
Published: January 2012

The spindle assembly checkpoint (SAC) plays an important role in mitotic cells to sense improper chromosome attachment to spindle microtubules and to inhibit APCFzy-dependent destruction of cyclin B and Securin; consequent initiation of anaphase until correct attachments are made. In Drosophila , SAC genes have been found to play a role in ensuring proper chromosome segregation in meiosis, possibly reflecting a similar role for the SAC in APCFzyinhibition during meiosis. We found that loss of function mutations in SAC genes, Mad2, zwilch, and mps1, do not lead to the predicted rise in APCFzy-dependent degradation of cyclin B either globally throughout the egg or locally on the meiotic spindle. Further, the SAC is not responsible for the inability of APCFzyto target cyclin B and promote anaphase in metaphase II arrested eggs from cort mutant females. Our findings support the argument that SAC proteins play checkpoint independent roles in Drosophila female meiosis and that other mechanisms must function to control APC activity.
Transcriptional regulation ofsdiAby cAMP-receptor protein, LeuO, and environmental signals inSalmonella entericaserovar Typhimurium
Authors: Turnbull Amy L. , Kim Wook , Surette Michael G.
Published: January 2012

The sdiA gene encodes for a LuxR-type transcription factor, which is active when bound to N-acyl homoserine lactones (AHLs). Because Salmonella enterica serovar Typhimurium does not produce AHLs, SdiA senses signals produced by other organisms. SdiA is not expressed constitutively, and response is limited to conditions in which elevated expression occurs, but little is known about the regulation of sdiA expression. Here we map the sdiA promoter and define several regulators that directly or indirectly act on the promoter. The major activator of sdiA expression is cAMP-receptor protein (CRP), and we define the CRP operator in the sdiA promoter using promoter and crp mutants. LeuO activates sdiA expression to a lesser extent than does CRP. We demonstrate that LeuO directly binds the sdiA promoter and the Rcs phosphorelay represses sdiA expression. In this study, NhaR, IlvY, and Fur affected sdiA expression indirectly and weakly. Expression in late-stationary phase depended on RpoS. AHL-dependent expression of the SdiA-regulated gene rck correlated to the observed sdiA transcriptional changes in regulator mutants. The data demonstrate that regulation of sdiA involves integration of multiple environmental and metabolic signals.
Mycobacterium marinuminfections in humans and tracing of its possible environmental sources
Authors: Slany Michal , Jezek Petr , Fiserova Vera , Bodnarova Monika , Stork Jiri , Havelkova Marta , Kalat Frantisek , Pavlik Ivo
Published: January 2012

The low frequency of nontuberculous mycobacterial infections, nonspecific symptoms for individual mycobacteria, and the lack of specific identification methods could alter correct diagnosis. This study presents a combined microbiology and molecular-based approach for Mycobacterium marinum detection in four aquarists with cutaneous mycobacterial infection. Simultaneously, ecology screening for M. marinum presence in the aquarists’ fish tanks was performed. A total of 38 mycobacterial isolates originated from four human patients (n = 20), aquarium animals (n = 8), and an aquarium environment (n = 10). Isolate identification was carried out using 16S rRNA sequence analysis. A microbiology-based approach, followed by 16S rRNA sequence analysis, was successfully used for detection of M. marinum in all four patients. Animal and environmental samples were simultaneously examined, and a total of seven mycobacterial species were isolated: Mycobacterium chelonae , Mycobacterium fortuitum , Mycobacterium gordonae , Mycobacterium kansasii , Mycobacterium mantenii , Mycobacterium marinum , and Mycobacterium peregrinum . The presence of M. marinum was proven in the aquarium environments of two patients. Although M. marinum is described as being present in water, it was detected only in fish.
Diversity and antimicrobial activities of the fungal endophyte community associated with the traditional Brazilian medicinal plant Solanum cernuum Vell. (Solanaceae)
Authors: Vieira Mariana L.A. , Hughes Alice F.S. , Gil Viviane B. , Vaz Aline B.M. , Alves Tânia M.A. , Zani Carlos L. , Rosa Carlos A. , Rosa Luiz H.
Published: January 2012

The diversity and antimicrobial activity of endophytic fungi associated with the Brazilian medicinal plant Solanum cernuum Vell. were studied during summer and winter seasons. A total of 246 fungal isolates were obtained, including 225 filamentous fungi and 21 yeasts. They were identified by morphological, physiological, and molecular methods. Fifty-five different taxa represented by the phyla Ascomycota (33 taxa), Basidiomycota (21 taxa), and Zygomycota (one taxon) were identified. The most abundant taxa were closely related to Arthrobotrys foliicola , Colletotrichum gloeosporioides , Coprinellus radians , Glomerella acutata , Diatrypella frostii , Phoma glomerata , Mucor sp., Phlebia subserialis , Phoma moricola , Phanerochaete sordida , and Colletotrichum sp. A total of 265 fungal extracts were screened and 64 (26.01%) displayed antimicrobial activities. Among these extracts, 18 (28.12%) presented antibacterial and antifungal activities, 42 (65.62%) displayed selective antibacterial activity, and four (6.25%) exhibited only antifungal activity. The best values of minimum inhibitory concentration were obtained from extracts of Cryptococcus rajasthanensis , Glomerella acutata, Leptosphaeria sp., and Phoma glomerata ranging from 7.8 to 15.62 µg/mL. This study is the first survey of the endophytic fungi community associated with S. cernuum, and our results show that they can represent a promising source of bioactive compounds.
Role forcheRofVibrio fischeriin theVibrio–squid symbiosis
Authors: DeLoney-Marino Cindy R. , Visick Karen L.
Published: January 2012

Upon hatching, the Hawaiian squid Euprymna scolopes is rapidly colonized by its symbiotic partner, the bioluminescent marine bacterium Vibrio fischeri . Vibrio fischeri cells present in the seawater enter the light organ of juvenile squid in a process that requires bacterial motility. In this study, we investigated the role chemotaxis may play in establishing this symbiotic colonization. Previously, we reported that V. fischeri migrates toward numerous attractants, including N-acetylneuraminic acid (NANA), a component of squid mucus. However, whether or not migration toward an attractant such as squid-derived NANA helps the bacterium to localize toward the light organ is unknown. When tested for the ability to colonize juvenile squid, a V. fischeri chemotaxis mutant defective for the methyltransferase CheR was outcompeted by the wild-type strain in co-inoculation experiments, even when the mutant was present in fourfold excess. Our results suggest that the ability to perform chemotaxis is an advantage during colonization, but not essential.
Multivitamin and mineral supplementation in 1,2-dimethylhydrazine induced experimental colon carcinogenesis and evaluation of free radical status, antioxidant potential, and incidence of ACF
Authors: Arul Albert Baskar , Savarimuthu Ignacimuthu , Alsaif Mohammed A. , Numair Khalid S. Al
Published: January 2012

This study was performed to determine the chemopreventive and antioxidant status of multivitamin and mineral (0.01% in drinking water, ad libitum) supplements in 1,2-dimethylhydrazine (DMH)-induced experimental colon carcinogenesis. Experimental colon carcinogenesis was induced in male albino Wistar rats by injecting DMH (20 mg·(kg body mass)–1) once weekly for 15 consecutive weeks, and administering a multivitamin supplement in 3 regimes (initiation, post-initiation, and entire experimental period) for 32 weeks. We studied lipid peroxidation products (thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes) in the circulation and in the tissues, antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and non-enzymatic antioxidant-reduced glutathione) of the tissues, aberrant crypt foci (ACF), and histopathological alterations. DMH-induced rats had an increase in lipid peroxidation products and a lower antioxidant status compared with control animals. Multivitamin and mineral supplementation during the initiation, post-initiation, and the entire study period significantly decreased the levels of lipid peroxidation products in circulation and colonic tissues, significantly elevated the activities of the antioxidant enzymes and reduced glutathione to near normalcy in DMH-induced rats. The incidence of ACF was reduced to 84.1% in rats supplemented with multivitamin and minerals for the entire study and prevented the colonic tissue from histopathological alterations induced by DMH.
Mechanisms involved in the differential reduction of omega-3 and omega-6 highly unsaturated fatty acids by structural heart disease resulting in “HUFA deficiency”
Authors: Rupp Heinz , Rupp Thomas P. , Alter Peter , Maisch Bernhard
Published: January 2012

The causes of reduced levels of omega-3 and omega-6 highly unsaturated fatty acids (“HUFA deficiency”) in heart failure remain unresolved. HUFA profiles were examined in the serum of 331 patients with failing versus nonfailing heart disease. Arachidonic acid was positively correlated (P < 0.001) with eicosapentaenoic acid (EPA) (r = 0.40) and docosahexaenoic acid (DHA) (r = 0.53) and negatively with palmitic (r = 0.42), palmitoleic (r = 0.38), and oleic acid (r = 0.48). Delta-5 desaturase activity was reduced (P < 0.01) in heart failure patients with low ejection fraction, dilatation, increased wall stress, and reduced heart rate variability (SDNN). In these patients, the reduced (P < 0.01) HUFA and increased palmitic (P < 0.01) and oleic acid (P = 0.05) arose from separate influences involving reduced cardiac contractility (arachidonic acid and palmitic acid predicted by ejection fraction) and chamber dilatation (DHA and oleic acid predicted by end-diastolic diameter). A low DHA (0.2%–0.9% versus 1.4%–3.1%) was associated (P < 0.025) with atrial dilatation (44 ± 8 mm versus 40 ± 8 mm). Equidirectional but less pronounced effects on HUFA were induced by sympathetic activation and (or) insulin resistance (fat and sugar fed to deoxycorticosterone acetate (DOCA)-salt rats) but not by compensated cardiac overload alone (DOCA-salt or aortic constriction), or reduced fatty acid oxidation (CPT-1 inhibition). Based on administration of omega-3 HUFA (OMACOR), dilatation is identified as a target for 1–2 g omega-3 HUFA·day–1. Interventions for reduced arachidonic acid remain to be explored.
Losartan inhibits STAT1 activation and protects human glomerular mesangial cells from angiotensin II induced premature senescence
Authors: Jiao Sumin , Zheng Xiaoyu , Yang Xue , Zhang Jin , Wang Lining
Published: January 2012

Human glomerular mesangial cells (HMCs) have a finite lifespan, and eventually enter irreversible growth arrest known as cellular senescence, which is thought to contribute to kidney ageing and age-related kidney disorders, such as chronic kidney disease. The signal transducer and activator of transcription 1 (STAT1) is a latent transcription factor involved in a variety of signal transduction pathways, including cell proliferation, apoptosis, and differentiation, but whether it could regulate HMC senescence still remains to be explored. In our study, the induction of angiotensin II (Ang II)-accelerated HMC senescence, as judged by increased senescence-associated β-galactosidase (SA-β-gal)-positive staining cells, morphological changes, and G0/G1 cell cycle arrest. STAT1 activity and the expression of p53 and p21Cip1were increased after Ang II treatment. STAT1 knockdown using RNA interference significantly inhibited the progression of HMC senescence and decreased the elevated expression of p53 and p21Cip1. Pretreating HMCs with Ang II receptor blocker losartan also inhibited the progression of HMC senescence and STAT1 activity. Our results indicate that STAT1 is implicated in the mediation of Ang II-induced HMC senescence through p53/ p21Cip1pathway, and that losartan could attenuate HMC senescence by regulating STAT1. The antioxidant N-acetyl-L-cysteine reduced ROS production and STAT1 activity induced by Ang II, indicating that Ang II uses ROS as a second messenger to regulate STAT1 activity.
A FILTER-BASED ALGORITHM FOR EFFICIENT COMPOSITION OF FINITE-STATE TRANSDUCERS
Authors: ALLAUZEN CYRIL , RILEY MICHAEL , SCHALKWYK JOHAN
Published: January 2012

This paper describes a weighted finite-state transducer composition algorithm that generalizes the concept of the composition filter and presents various filters that process epsilon transitions, look-ahead along paths, and push forward labels along epsilon paths. These filters, either individually or in combination, make it possible to compose some transducers much more efficiently in time and space than otherwise possible. We present examples of this drawn, in part, from demanding speech-processing applications. The generalized composition algorithm and many of these filters have been included in Open-Fst, an open-source weighted transducer library.
STATE COMPLEXITY OF TWO COMBINED OPERATIONS: CATENATION-UNION AND CATENATION-INTERSECTION
Authors: CUI BO , GAO YUAN , KARI LILA , YU SHENG
Published: January 2012

In this paper, we study the state complexities of two particular combinations of operations: catenation combined with union and catenation combined with intersection. We show that the state complexity of the former combined operation is considerably less than the mathematical composition of the state complexities of catenation and union, while the state complexity of the latter one is equal to the mathematical composition of the state complexities of catenation and intersection.
WEIGHTED AUTOMATA AND REGULAR EXPRESSIONS OVER VALUATION MONOIDS
Authors: DROSTE MANFRED , MEINECKE INGMAR
Published: January 2012

Quantitative aspects of systems like consumption of resources, output of goods, or reliability can be modeled by weighted automata. Recently, objectives like the average cost or the longtime peak power consumption of a system have been modeled by weighted automata which are not semiring weighted anymore. Instead, operations like limit superior, limit average, or discounting are used to determine the behavior of these automata. Here, we introduce a new class of weight structures subsuming a range of these models as well as semirings. Our main result shows that such weighted automata and Kleene-type regular expressions are expressively equivalent both for finite and infinite words.
APPROXIMATION ALGORITHMS FOR BUY-AT-BULK GEOMETRIC NETWORK DESIGN
Authors: CZUMAJ ARTUR , CZYZOWICZ JUREK , GĄSIENIEC LESZEK , JANSSON JESPER , LINGAS ANDRZEJ , ZYLINSKI PAWEL
Published: January 2012

The buy-at-bulk network design problem has been extensively studied in the general graph model. In this paper, we consider geometric versions of the problem, where all points in a Euclidean space are candidates for network nodes, and present the first general approach for solving them. It enables us to obtain quasi-polynomial-time approximation schemes for basic variants of the buy-at-bulk geometric network design problem with polynomial total demand. Then, for instances with a single sink and low capacity links, we design fast polynomial-time, low-constant approximation algorithms.
THE GRAPH-BIN PACKING PROBLEM
Authors: BUJTÁS CSILLA , DÓSA GYÖRGY , IMREH CSANÁD , NAGY-GYÖRGY JUDIT , TUZA ZSOLT
Published: January 2012

We deal with a very general problem: a given graph G is to be "packed" into a host graph H, and we are asked about some natural optimization questions concerning this packing. The problem has never been investigated before in this general form. The input of the problem is a simple graph G = (V, E) with lower and upper bounds on its edges and weights on its vertices. The vertices correspond to items which have to be packed into the vertices (bins) of a host graph, such that each host vertex can accommodate at most L weight in total, and if two items are adjacent in G, then the distance of their host vertices in H must be between the lower and upper bounds of the edge joining the two items. Special cases are bin packing with conflicts, chromatic number, and many more. We give some general structure statements, treat some special cases, and investigate the performance guarantee of polynomial-time algorithms both in the offline and online setting.
RULE RESPONDER: RULE-BASED AGENTS FOR THE SEMANTIC-PRAGMATIC WEB
Authors: PASCHKE ADRIAN , BOLEY HAROLD
Published: January 2012

Rule Responder is a Pragmatic Web infrastructure for distributed rule-based event processing multi-agent eco-systems. This allows specifying virtual organizations — with their shared and individual (semantic and pragmatic) contexts, decisions, and actions/events for rule-based collaboration between the distributed members. The (semi-)autonomous agents use rule engines and Semantic Web rules to describe and execute derivation and reaction logic which declaratively implements the organizational semiotics and the different distributed system/agent topologies with their negotiation/coordination mechanisms. They employ ontologies in their knowledge bases to represent semantic domain vocabularies, normative pragmatics and pragmatic context of event-based conversations and actions.
A COLLABORATIVE APPROACH TO CONSTRUCTION OF LARGE SCALE DISTRIBUTED REASONING SYSTEMS
Authors: PENDERS ATE , PAVLIN GREGOR , KAMERMANS MICHIEL
Published: January 2012

This paper introduces a new collaborative approach to construction of large scale service oriented systems supporting distributed reasoning. In particular, we assume systems in which complex situation assessment is carried out through composition of heterogeneous services, each specialized for a particular type of analysis. Different services are composed automatically by using service discovery and negotiation. One of the major challenges in such settings is efficient definition of a large number of different types of services. The presented solution supports efficient definition of services by using a combination of light weight service ontologies, efficient construction procedures and tools. In particular, machine-understandable descriptions of heterogeneous services with well defined syntax and semantics can be created by multiple designers, without complex coordination of collaborative design processes and without any knowledge of formal ontologies.
CYLINDRICAL THIN-SHELL WORMHOLES AND ENERGY CONDITIONS
Authors: SIMEONE CLAUDIO
Published: January 2012

We prove the impossibility of cylindrical thin-shell wormholes supported by matter satisfying the energy conditions everywhere, under reasonable assumptions about the asymptotic behavior of the –in general different–metrics at each side of the throat. Besides, we establish necessary conditions for the possibility of non-exotic thin-shell wormholes.
QUANTUM TUNNELING AND SPECTROSCOPY OF NONCOMMUTATIVE INSPIRED KERR BLACK HOLE
Authors: MIAO YAN-GANG , XUE ZHAO , ZHANG SHAO-JUN
Published: January 2012

We discuss the thermodynamics of the noncommutative inspired Kerr black hole by means of a reformulated Hamilton–Jacobi method and a dimensional reduction technique. In order to investigate the effect of the angular momentum of the tunneling particle, we calculate the wave function to the first order of the WKB ansatz. Then, using a density matrix technique we derive the radiation spectrum from which the radiation temperature can be read out. Our results show that the radiation of this noncommutative inspired black hole corresponds to a modified temperature which involves the effect of noncommutativity. However, the angular momentum of the tunneling particle has no influence on the radiation temperature. Moreover, we analyze the entropy spectrum and verify that its quantization is modified neither by the noncommutativity of spacetime nor by the quantum correction of wave functions.
EVOLVING NETWORKS PROMOTES COOPERATION IN PUBLIC GOODS GAMES
Authors: BAZZAN A. L. C. , ARGENTA V. F.
Published: January 2012

Evolution of cooperation has attracted considerable attention but so far no definitive answer exists. Probably each kind of problem has specific answers. This paper deals with evolution of cooperation in public goods games. We use random Boolean networks to formalize the non-local influence of K agents over a given agent. This formalism allows the representation of a variety of network regulation mechanisms by means of (i) different topologies and (ii) Boolean functions that do the regulation proper. However, random functions and connections do not necessarily lead to cooperation. Thus, it is necessary to find what kind of network structure is prone to promote cooperation. We employ an evolutionary approach to show that evolving the topologies and the random functions leads to much fitter structures.
Relaxation Due to the Partial Swap Collisions with a Random Reservoir
Authors: Gennaro Giuseppe
Published: January 2012

We analyze the dynamics of the system consisting of a qubit sequentially interacting with a chain of qubits that are initially individually in a pure random state. Each pairwise collision has been modeled as a partial swap transformation. The relaxation to equilibrium of the purity of the system qubit, averaged over all the initial states of the environment, is analytically computed. In particular, we show that the steady state depends on the parameter η of the partial swap transformation. Finally, we investigate aspects of the entanglement dynamics for qubits and show that such process can create typical multipartite entanglement between the system qubit and the qubits of the chain.
Physical prototyping of an on-outlet power-consumption display
Authors: Heller Florian , Borchers Jan
Published: January 2012

Sustainability in (Inter)Action provides a forum for innovative thought, design, and research in the area of interaction design and environmental sustainability. The column explores how HCI can contribute to the complex and interdisciplinary efforts to address sustainability challenges.

Elaine M. Huang, Editor
Designing interactive systems in healthcare
Authors: Reddy Madhu , Mamykina Lena , Parker Andrea Grimes
Published: January 2012

This forum is dedicated to personal health in all its many facets: decision-making, goal setting, celebration, discovery, reflection, coordination---even entertainment. We'll look at innovations in interactive technologies and how they help address current critical healthcare challenges.

Elizabeth D. Mynatt, Editor
Design case study
Authors: Newman William
Published: January 2012

Timelines provides perspectives on HCI history, glancing back at a road that sometimes took unexpected branches and turns. History is not a dry list of events; it is about points of view and differing interpretations.
Jonathan Grudin, Editor
What Are You Working On?
Authors: Townsend Simon
Published: January 2012

Is it possible to hold a conversation with thousands of voices? Multinational firm Deloitte uses Yammer to strip away distance, hierarchy, and service line divisions to enable real-time knowledge sharing among its employees. Simon Townsend was there from the start and watched the micro-blogging tool grow from a small virtual water cooler to a global network of more than 180,000 users.
How to Build and Lead Successful Online Communities: What makes a community a community?
Authors: Laycock Nic
Published: January 2012

In this first in a series on learning communities, eLearn contributor Nic Laycock defines what makes a community and discusses the importance of online communities for learning and development.
Conversion of binary to single-term triple base numbers for DSP applications
Authors: Chakraborty Anindita , Sinha Amitabha
Published: January 2012

Non-binary number systems are increasingly gaining popularity in signal processing applications for their capabilities of handling arithmetic operations efficiently. One such number system, "Double Base Number System (DBNS)" has gained attention to many researchers for it's capability of performing multiplication operation efficiently. Recently, "Triple Base Number System (TBNS)" has been introduced which shows better performance over DBNS for higher bit operations in terms of speed, hardware complexity and power dissipation. However, the advantages of TBNS systems cannot be exploited due to substantial overhead of conversion from binary to TBNS. Keeping this issue in view, in this paper, a novel architecture has been proposed for high performance binary to TBNS conversion. Efficiency of this conversion scheme has been dealt with in details and experimental results and analysis clearly indicate the novelty of the architecture.
IR research
Authors: Järvelin Kalervo
Published: January 2012

The practical goal of information retrieval (IR) research is to create ways to support humans to better access information in order to better carry out their tasks. Because of this, IR research has a primarily technological interest in knowledge creation -- how to interact with information (better)? IR research therefore has a constructive aspect (to create novel systems) and an evaluative aspect (are they any good?). Evaluation of IR effectiveness is guided by a theory on factors that affect effectiveness. True science is about theory development, i.e., understanding and explaining, making hypotheses and testing them. Theories express structured explanatory relationships between variables such as "type of document indexing" and "quality of ranking measured by MAP". Theories are the better, the wider range of phenomena they are able cover accurately. The paper argues that most existing theories of IR are focused on a narrow scope, theories of ranking. To fulfill its task of supporting human information access, theories that go beyond the evaluation of ranking are highly desired but face many challenges. We discuss three additional types of IR theories: theories of searching, theories of information access, and theories of information interaction.