bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced retention characteristic of NiSi2/SiNx compound nanocrystal memory
Authors: Lu Jin , Chang Ting-Chang , Chen Yu-Ting , Huang Jheng-Jie , Yang Po-Chun , Chen Shih-Ching , Huang Hui-Chun , Gan Der-Shin , Ho New-Jin , Shi Yi , Chu Ann-Kuo
Published: June 2010

The NiSi2/SiNx compound nanocrystals (CNCs) were fabricated to integrate the compound tunnel barrier into nanocrystal memory, with the inclusion of nitride traps. The analysis of high resolution transmission electron microscopy and x-ray photoelectron spectroscopy reveal that the nanocrystal is mainly composed of NiSi2 and silicon nitride with small size of 4–5 nm and high density of ∼1×1012 cm−2. The charge storage characteristics of the memory capacitor based on NiSi2/SiNx CNCs were investigated by capacitance-voltage measurement and the enhanced retention characteristics, which remain 71.7% (∼1.9 V) in 104 s, are clarified to be due to the compound tunnel barrier and traps in nitride.
Anisotropic and enhanced absorptive nonlinearities in a macroscopic film induced by aligned gold nanorods
Authors: Li Jiafang , Liu Siyun , Liu Ye , Zhou Fei , Li Zhi-Yuan
Published: June 2010

Anisotropic and enhanced nonlinear absorption (NLA) has been observed from aligned gold nanorods (GNRs) embedded in a poly(vinyl alcohol) film, which was realized by a stretched-film method. Open-aperture Z-scan experiments revealed that the stretch process enhanced the NLA coefficient by approximately nine times and increased the anisotropic factor of NLA to ∼20. The enhancement in the NLA coefficient reached as high as ∼91 times after increasing the concentration of GNRs by four times and this is attributed to the plasmonic interaction between densely packed GNRs.
Electron transfer mechanism of cytochrome c at graphene electrode
Authors: Alwarappan Subbiah , Joshi Rakesh K. , Ram Manoj K. , Kumar Ashok
Published: June 2010

We report the direct electron transfer of cytochrome c (Cyt c) observed at graphene electrodes. Graphene nanosheets were chemically synthesized and immobilized on to a glassy carbon electrode. Cyclic voltammetry of Cyt c in phosphate buffered saline was performed at these electrodes. Results indicated a pair of reversible redox waves with a peak-to-peak separation value of 0.07 V in a diffusion controlled electrochemical process. Furthermore, the voltammetric response of these electrodes in Cyt c were found to be stable over time with negligible electrode fouling toward Cyt c.
Femtosecond laser near-field nanoablation patterning using Mie resonance high dielectric constant particle with small size parameter
Authors: Tanaka Yuto , Obara Go , Zenidaka Akira , Terakawa Mitsuhiro , Obara Minoru
Published: June 2010

We demonstrate near-field nanohole patterning using a Mie resonance, small size parameter particle for nanofabrication technology regardless of substrate’s refractive index. Maximal enhancement factor and nearly smallest spot diameter among the same size dielectric particles are simultaneously obtainable on both low-refractive-index SiO2 and high-refractive-index Si substrates with a 200 nm particle of magnetic quadrupole resonance scattering mode (n∼2.7) at 400 nm excitation wavelength. Circular nanoholes with approximately 100 nm in diameter were fabricated on both substrates using a 200 nm amorphous TiO2 particle (n=2.66+0.024i) even with lower laser fluences than a half ablation threshold of the bare substrates.
Molecular phylogeny of the freshwater prawn genus Macrobrachium (Decapoda, Palaemonidae), with emphasis on the relationships among selected American species
Authors: Pileggi Leonardo G. , Mantelatto Fernando L.
Published: June 2010

The genus Macrobrachium Bate, 1868 is one of the best examples of widespread crustacean genera distributed globally throughout tropical and subtropical waters. Previous investigators have noted the systematic complexity of the group, and have suggested rearrangements within the family Palaemonidae. Our phylogenetic analysis of new mitochondrial DNA sequences of 58 species of Macrobrachium distributed mainly in America support the hypothesis of monophyly of this genus, if Cryphiops Dana, 1852 is accepted as a generic synonym. We concluded that the independent evolution of different types of life cycle (abbreviated larval development – ALD and extended larval development – ELD) must have occurred more than once in the history of the group. Similarly, we also concluded that the current type species of the genus, Macrobrachium americanum Bate, 1868, should not be considered valid, as previously proposed. The synonymy of two members of the ‘olfersi’ species complex (M. birai Lobão, Melo & Fernandes, 1986 and M. holthuisi Genofre & Lobão, 1978) with M. olfersi (Wiegmann, 1836) was confirmed. Similar results were found in comparing M. petronioi Melo, Lobão & Fernandes, 1986 and M. potiuna (Müller, 1880), in which the genetic divergence placed M. petronioi within the level of intraspecific variation of M. potiuna. The taxonomic status of the genus Cryphiops, as well as theories on the origin of Macrobrachium, is also called into question.
Double-stranded DNA homology produces a physical signature
Authors: Wang Xing , Zhang Xiaoping , Mao Chengde , Seeman Nadrian C.
Published: June 2010

DNA is found in the cell largely as a negatively supercoiled molecule. This high-energy form of the genetic material can engender sequence-dependent structures, such as cruciforms, Z-DNA, or H-DNA, even though they are not favored by conventional conditions in relaxed DNA. A key feature of DNA in living systems is the presence of homology. We have sought homology-dependent structural phenomena based on topological relaxation. Using two-dimensional electrophoresis, we demonstrate a structural transition in supercoiled plasmid molecules containing homologous segments. Atomic force microscopy (AFM) reveals a dumbbell structure in molecules whose linking difference is beyond the transition point. The position of the dumbbell shaft is a function of the site of homology, and its extent is proportional to the linking difference. Second-site-reversion electrophoresis data support the notion that the shaft contains PX-DNA. Predicted cross-linking patterns generated in vivo suggest that homology-dependent structures can occur within the cell.
Specific insertions of zinc finger domains into Gag-Pol yield engineered retroviral vectors with selective integration properties
Authors: Lim Kwang-il , Klimczak Ryan , Yu Julie H. , Schaffer David V.
Published: June 2010

Retroviral vectors offer benefits of efficient delivery and stable gene expression; however, their clinical use raises the concerns of insertional mutagenesis and potential oncogenesis due to genomic integration preferences in transcriptional start sites (TSS). We have shifted the integration preferences of retroviral vectors by generating a library of viral variants with a DNA-binding domain inserted at random positions throughout murine leukemia virus Gag-Pol, then selecting for variants that are viable and exhibit altered integration properties. We found seven permissive zinc finger domain (ZFD) insertion sites throughout Gag-Pol, including within p12, reverse transcriptase, and integrase. Comprehensive genome integration analysis showed that several ZFD insertions yielded retroviral vector variants with shifted integration patterns that did not favor TSS. Furthermore, integration site analysis revealed selective integration for numerous mutants. For example, two retroviral variants with a given ZFD at appropriate positions in Gag-Pol strikingly integrated primarily into four common sites out of 3.1 × 10
9
possible human genome locations (P = 4.6 × 10
-29
). Our findings demonstrate that insertion of DNA-binding motifs into multiple locations in Gag-Pol can make considerable progress toward engineering safer retroviral vectors that integrate into a significantly narrowed pool of sites on human genome and overcome the preference for TSS.
Inferring individual rules from collective behavior
Authors: Lukeman Ryan , Li Yue-Xian , Edelstein-Keshet Leah
Published: June 2010

Social organisms form striking aggregation patterns, displaying cohesion, polarization, and collective intelligence. Determining how they do so in nature is challenging; a plethora of simulation studies displaying life-like swarm behavior lack rigorous comparison with actual data because collecting field data of sufficient quality has been a bottleneck. Here, we bridge this gap by gathering and analyzing a high-quality dataset of flocking surf scoters, forming well-spaced groups of hundreds of individuals on the water surface. By reconstructing each individual's position, velocity, and trajectory, we generate spatial and angular neighbor-distribution plots, revealing distinct concentric structure in positioning, a preference for neighbors directly in front, and strong alignment with neighbors on each side. We fit data to zonal interaction models and characterize which individual interaction forces suffice to explain observed spatial patterns. Results point to strong short-range repulsion, intermediate-range alignment, and longer-range attraction (with circular zones), as well as a weak but significant frontal-sector interaction with one neighbor. A best-fit model with such interactions accounts well for observed group structure, whereas absence or alteration in any one of these rules fails to do so. We find that important features of observed flocking surf scoters can be accounted for by zonal models with specific, well-defined rules of interaction.
Regulation of human metabolism by hypoxia-inducible factor
Authors: Formenti Federico , Constantin-Teodosiu Dumitru , Emmanuel Yaso , Cheeseman Jane , Dorrington Keith L. , Edwards Lindsay M. , Humphreys Sandy M. , Lappin Terence R. J. , McMullin Mary F. , McNamara Christopher J. , Mills Wendy , Murphy John A. , O'Connor David F. , Percy Melanie J. , Ratcliffe Peter J. , Smith Thomas G. , Treacy Marilyn , Frayn Keith N. , Greenhaff Paul L. , Karpe Fredrik , Clarke Kieran , Robbins Peter A.
Published: June 2010

The hypoxia-inducible factor (HIF) family of transcription factors directs a coordinated cellular response to hypoxia that includes the transcriptional regulation of a number of metabolic enzymes. Chuvash polycythemia (CP) is an autosomal recessive human disorder in which the regulatory degradation of HIF is impaired, resulting in elevated levels of HIF at normal oxygen tensions. Apart from the polycythemia, CP patients have marked abnormalities of cardiopulmonary function. No studies of integrated metabolic function have been reported. Here we describe the response of these patients to a series of metabolic stresses: exercise of a large muscle mass on a cycle ergometer, exercise of a small muscle mass (calf muscle) which allowed noninvasive in vivo assessments of muscle metabolism using
31
P magnetic resonance spectroscopy, and a standard meal tolerance test. During exercise, CP patients had early and marked phosphocreatine depletion and acidosis in skeletal muscle, greater accumulation of lactate in blood, and reduced maximum exercise capacities. Muscle biopsy specimens from CP patients showed elevated levels of transcript for pyruvate dehydrogenase kinase, phosphofructokinase, and muscle pyruvate kinase. In cell culture, a range of experimental manipulations have been used to study the effects of HIF on cellular metabolism. However, these approaches provide no potential to investigate integrated responses at the level of the whole organism. Although CP is relatively subtle disorder, our study now reveals a striking regulatory role for HIF on metabolism during exercise in humans. These findings have significant implications for the development of therapeutic approaches targeting the HIF pathway.
Biological role of noise encoded in a genetic network motif
Authors: Kittisopikul Mark , Süel Gürol M.
Published: June 2010

Genetic circuits that regulate distinct cellular processes can differ in their wiring pattern of interactions (architecture) and susceptibility to stochastic fluctuations (noise). Whether the link between circuit architecture and noise is of biological importance remains, however, poorly understood. To investigate this problem, we performed a computational study of gene expression noise for all possible circuit architectures of feed-forward loop (FFL) motifs. Results revealed that FFL architectures fall into two categories depending on whether their ON (stimulated) or OFF (unstimulated) steady states exhibit noise. To explore the biological importance of this difference in noise behavior, we analyzed 858 documented FFLs in
Escherichia coli
that were divided into 39 functional categories. The majority of FFLs were found to regulate two subsets of functional categories. Interestingly, these two functional categories associated with FFLs of opposite noise behaviors. This opposite noise preference revealed two noise-based strategies to cope with environmental constraints where cellular responses are either initiated or terminated stochastically to allow probabilistic sampling of alternative states. FFLs may thus be selected for their architecture-dependent noise behavior, revealing a biological role for noise that is encoded in gene circuit architectures.
Neurons in the anterior olfactory nucleus pars externa detect right or left localization of odor sources
Authors: Kikuta Shu , Sato Kenichiro , Kashiwadani Hideki , Tsunoda Koichi , Yamasoba Tatsuya , Mori Kensaku
Published: June 2010

Rodents can localize odor sources by comparing odor inputs to the right and left nostrils. However, the neuronal circuits underlying such odor localization are not known. We recorded neurons in the anterior olfactory nucleus (AON) while administering odors to the ipsilateral or contralateral (ipsi- or contra-) nostril. Neurons in the AON pars externa (AONpE) showed respiration phase-locked excitatory spike responses to ipsinostril-only stimulation with a category of odorants, and inhibitory responses to contranostril-only stimulation with the same odorants. Simultaneous odor stimulation of the ipsi- and contranostrils elicited significantly smaller responses than ipsinostril-only stimulation, indicating that AONpE neurons subtract the contranostril odor inputs from ipsinostril odor inputs. An ipsilateral odor source induced larger responses than a centrally located source, whereas an odor source at the contralateral position elicited inhibitory responses. These results indicate that individual AONpE neurons can distinguish the right or left position of an odor source by referencing signals from the two nostrils.
Regulation of phenotypic variability by a threshold-based mechanism underlies bacterial persistence
Authors: Rotem Eitan , Loinger Adiel , Ronin Irine , Levin-Reisman Irit , Gabay Chana , Shoresh Noam , Biham Ofer , Balaban Nathalie Q.
Published: June 2010

In the face of antibiotics, bacterial populations avoid extinction by harboring a subpopulation of dormant cells that are largely drug insensitive. This phenomenon, termed “persistence,” is a major obstacle for the treatment of a number of infectious diseases. The mechanism that generates both actively growing as well as dormant cells within a genetically identical population is unknown. We present a detailed study of the toxin–antitoxin module implicated in antibiotic persistence of
Escherichia coli
. We find that bacterial cells become dormant if the toxin level is higher than a threshold, and that the amount by which the threshold is exceeded determines the duration of dormancy. Fluctuations in toxin levels above and below the threshold result in coexistence of dormant and growing cells. We conclude that toxin–antitoxin modules in general represent a mixed network motif that can serve to produce a subpopulation of dormant cells and to supply a mechanism for regulating the frequency and duration of growth arrest. Toxin–antitoxin modules thus provide a natural molecular design for implementing a bet-hedging strategy.
Tailored cancer immunotherapy using combinations of chemotherapy and a mixture of antibodies against EGF-receptor ligands
Authors: Lindzen Moshit , Lavi Sara , Leitner Orith , Yarden Yosef
Published: June 2010

Growth factors are implicated in several processes essential for cancer progression. Specifically, growth factors that bind to ErbB family receptors have been implicated in cell proliferation and in resistance of solid tumors to chemotherapy. We quantified ligand secretion by several human cancer cell lines, and generated mAbs against two ligands, namely TGF-α and heparin-binding EGF-like growth factor. These growth factors are frequently secreted by pancreatic tumor cell lines, including BxPC3 cells. The monoclonal antibodies were tested for their antigen specificity and ability to inhibit growth of BxPC3 cells in vitro. Combining the two antibodies resulted in enhanced inhibition of BxPC3 cell growth, both in vitro and in tumor-bearing animals. Hence, we combined the two antibodies with gemcitabine, an effective chemotherapeutic drug commonly used to treat pancreatic cancer patients. Because treatment with a combination of two monoclonal antibodies enhanced the ability of chemotherapy to inhibit BxPC3 tumors in mice, we propose a general cancer therapeutic strategy that entails profiling the repertoire of growth factors secreted by a tumor, and combining with chemotherapy several antibodies capable of blocking autocrine ligands.
Programmed necrosis induced by asbestos in human mesothelial cells causes high-mobility group box 1 protein release and resultant inflammation
Authors: Yang Haining , Rivera Zeyana , Jube Sandro , Nasu Masaki , Bertino Pietro , Goparaju Chandra , Franzoso Guido , Lotze Michael T. , Krausz Thomas , Pass Harvey I. , Bianchi Marco E. , Carbone Michele
Published: June 2010

Asbestos carcinogenesis has been linked to the release of cytokines and mutagenic reactive oxygen species (ROS) from inflammatory cells. Asbestos is cytotoxic to human mesothelial cells (HM), which appears counterintuitive for a carcinogen. We show that asbestos-induced HM cell death is a regulated form of necrosis that links to carcinogenesis. Asbestos-exposed HM activate poly(ADP-ribose) polymerase, secrete H2O2, deplete ATP, and translocate high-mobility group box 1 protein (HMGB1) from the nucleus to the cytoplasm, and into the extracellular space. The release of HMGB1 induces macrophages to secrete TNF-α, which protects HM from asbestos-induced cell death and triggers a chronic inflammatory response; both favor HM transformation. In both mice and hamsters injected with asbestos, HMGB1 was specifically detected in the nuclei, cytoplasm, and extracellular space of mesothelial and inflammatory cells around asbestos deposits. TNF-α was coexpressed in the same areas. HMGB1 levels in asbestos-exposed individuals were significantly higher than in nonexposed controls (P< 0.0001). Our findings identify the release of HMGB1 as a critical initial step in the pathogenesis of asbestos-related disease, and provide mechanistic links between asbestos-induced cell death, chronic inflammation, and carcinogenesis. Chemopreventive approaches aimed at inhibiting the chronic inflammatory response, and especially blocking HMGB1, may decrease the risk of malignant mesothelioma among asbestos-exposed cohorts.
Laminar and columnar auditory cortex in avian brain
Authors: Wang Yuan , Brzozowska-Prechtl Agnieszka , Karten Harvey J.
Published: June 2010

The mammalian neocortex mediates complex cognitive behaviors, such as sensory perception, decision making, and language. The evolutionary history of the cortex, and the cells and circuitry underlying similar capabilities in nonmammals, are poorly understood, however. Two distinct features of the mammalian neocortex are lamination and radially arrayed columns that form functional modules, characterized by defined neuronal types and unique intrinsic connections. The seeming inability to identify these characteristic features in nonmammalian forebrains with earlier methods has often led to the assumption of uniqueness of neocortical cells and circuits in mammals. Using contemporary methods, we demonstrate the existence of comparable columnar functional modules in laminated auditory telencephalon of an avian species (
Gallus gallus
). A highly sensitive tracer was placed into individual layers of the telencephalon within the cortical region that is similar to mammalian auditory cortex. Distribution of anterograde and retrograde transportable markers revealed extensive interconnections across layers and between neurons within narrow radial columns perpendicular to the laminae. This columnar organization was further confirmed by visualization of radially oriented axonal collaterals of individual intracellularly filled neurons. Common cell types in birds and mammals that provide the cellular substrate of columnar functional modules were identified. These findings indicate that laminar and columnar properties of the neocortex are not unique to mammals and may have evolved from cells and circuits found in more ancient vertebrates. Specific functional pathways in the brain can be analyzed in regard to their common phylogenetic origins, which introduces a previously underutilized level of analysis to components involved in higher cognitive functions.
Fibroblast growth factor 21 regulates energy metabolism by activating the AMPK–SIRT1–PGC-1α pathway
Authors: Chau Mary D. L. , Gao Jiaping , Yang Qing , Wu Zhidan , Gromada Jesper
Published: June 2010

Fibroblast growth factor 21 (FGF21) has been identified as a potent metabolic regulator. Administration of recombinant FGF21 protein to rodents and rhesus monkeys with diet-induced or genetic obesity and diabetes exerts strong antihyperglycemic and triglyceride-lowering effects and reduction of body weight. Despite the importance of FGF21 in the regulation of glucose, lipid, and energy homeostasis, the mechanisms by which FGF21 functions as a metabolic regulator remain largely unknown. Here we demonstrate that FGF21 regulates energy homeostasis in adipocytes through activation of AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), resulting in enhanced mitochondrial oxidative function. AMPK phosphorylation levels were increased by FGF21 treatment in adipocytes as well as in white adipose tissue from
ob/ob
mice. FGF21 treatment increased cellular NAD
+
levels, leading to activation of SIRT1 and deacetylation of its downstream targets, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and histone 3. Activation of AMPK and SIRT1 by FGF21 in adipocytes enhanced mitochondrial oxidative capacity as demonstrated by increases in oxygen consumption, citrate synthase activity, and induction of key metabolic genes. The effects of FGF21 on mitochondrial function require serine/threonine kinase 11 (STK11/LKB1), which activates AMPK. Inhibition of AMPK, SIRT1, and PGC-1α activities attenuated the effects of FGF21 on oxygen consumption and gene expression, indicating that FGF21 regulates mitochondrial activity and enhances oxidative capacity through an AMPK–SIRT1–PGC1α–dependent mechanism in adipocytes.
A single social defeat reduces aggression in a highly aggressive strain of
Drosophila
Authors: Penn Jill K. M. , Zito Michael F. , Kravitz Edward A.
Published: June 2010

Genes and prior experience both influence the behavior of animals, but the relative contribution of each to fighting behavior in
Drosophila
remains unclear. To address this issue, we bred hyperaggressive flies by selecting winners of fights over 34–37 generations. Males of this strain initiate fights sooner, retaliate more often, and regularly defeat opponents from the nonselected parent Canton-S strain. After a defeat, however, these highly aggressive flies lose their second fights against socially naïve counterparts. Defeated flies also lunge and retaliate less after experiencing a loss, suggesting that the subsequent losses result from flies becoming less aggressive. Remarkably, flies that were once capable of engaging in high-intensity boxing and tussling patterns of behavior for extended periods of time often do not even engage in mid-intensity lunging after a single defeat. Furthermore, these formerly highly aggressive flies lose all competitive advantage over nonselected Canton-S after experiencing a loss. Lastly, females were more likely to copulate with males from the nonselected parent line than with the hyperaggressive strain.
Topological basis for the robust distribution of blood to rodent neocortex
Authors: Blinder Pablo , Shih Andy Y. , Rafie Christopher , Kleinfeld David
Published: June 2010

The maintenance of robust blood flow to the brain is crucial to the health of brain tissue. We examined the pial network of the middle cerebral artery, which distributes blood from the cerebral arteries to the penetrating arterioles that source neocortical microvasculature, to characterize how vascular topology may support such robustness. For both mice and rats, two features dominate the topology. First, interconnected loops span the entire territory sourced by the middle cerebral artery. Although the loops comprise <10% of all branches, they maintain the overall connectivity of the network after multiple breaks. Second, >80% of offshoots from the loops are stubs that end in a single penetrating arteriole, as opposed to trees with multiple penetrating arterioles. We hypothesize that the loops and stubs protect blood flow to the parenchyma from an occlusion in a surface vessel. To test this, we assayed the viability of tissue that was sourced by an individual penetrating arteriole following occlusion of a proximal branch in the surface loop. We observed that neurons remained healthy, even when occlusion led to a reduction in the local blood flow. In contrast, direct blockage of a single penetrating arteriole invariably led to neuronal death and formation of a cyst. Our results show that the surface vasculature functions as a grid for the robust allocation of blood in the event of vascular dysfunction. The combined results of the present and prior studies imply that the pial network reallocates blood in response to changing metabolic needs.
The discourse of widening participation and its critics: an institutional case study
Authors: Stevenson Jacqueline , Clegg Sue , Lefever Ruth
Published: June 2010

This paper takes as its focus the contradictory discourse of widening participation (WP). We argue that given the conflicting accounts of WP it is highly unlikely that higher education staff will be able articulate a coherent definition of WP practice. We illustrate our thesis with
an institutional case study which analysed policy documents and was based on in-depth interviews with staff. We found that not only did staff have contradictory definitions of WP, but that those who saw themselves as committed questioned the commitment of others. Thus despite institutional
rhetoric our participants fell back on personal values when implementing WP activity.
The Plasmodium eukaryotic initiation factor-2α kinase IK2 controls the latency of sporozoites in the mosquito salivary glands
Authors: Zhang Min , Fennell Clare , Ranford-Cartwright Lisa , Sakthivel Ramanavelan , Gueirard Pascale , Meister Stephan , Caspi Anat , Doerig Christian , Nussenzweig Ruth S. , Tuteja Renu , Sullivan William J. , Roos David S. , Fontoura Beatriz M.A. , Ménard Robert , Winzeler Elizabeth A. , Nussenzweig Victor
Published: June 2010

Sporozoites, the invasive form of malaria parasites transmitted by mosquitoes, are quiescent while in the insect salivary glands. Sporozoites only differentiate inside of the hepatocytes of the mammalian host. We show that sporozoite latency is an active process controlled by a eukaryotic initiation factor-2α (eIF2α) kinase (IK2) and a phosphatase. IK2 activity is dominant in salivary gland sporozoites, leading to an inhibition of translation and accumulation of stalled mRNAs into granules. When sporozoites are injected into the mammalian host, an eIF2α phosphatase removes the PO4 from eIF2α-P, and the repression of translation is alleviated to permit their transformation into liver stages. In IK2 knockout sporozoites, eIF2α is not phosphorylated and the parasites transform prematurely into liver stages and lose their infectivity. Thus, to complete their life cycle, Plasmodium sporozoites exploit the mechanism that regulates stress responses in eukaryotic cells.
Incidence of Surgical Site Infection Associated with Robotic Surgery
Authors: Hermsen Elizabeth D. , Hinze Tim , Sayles Harlan , Sholtz Lee , Rupp Mark E.
Published: June 2010

Objective.

Robot-assisted surgery is minimally invasive and associated with less blood loss and shorter recovery time than open surgery. We aimed to determine the duration of robot-assisted surgical procedures and the incidence of postoperative surgical site infection (SSI) and to compare our data with the SSI incidence for open procedures according to national data.

Design.

Retrospective cohort study.

Setting.

A 689-bed academic medical center.

Patients.

All patients who underwent a surgical procedure with use of a robotic surgical system during the period from 2000-2007.

Methods.

SSIs were defined and procedure types were classified according to National Healthcare Safety Network criteria. National data for comparison were from 1992-2004. Because of small sample size, procedures were grouped according to surgical site or wound classification.

Results.

Sixteen SSIs developed after 273 robot-assisted procedures (5.9%). The mean surgical duration was 333.6 minutes. Patients who developed SSI had longer mean surgical duration than did patients who did not (558 vs 318 minutes; P<.001). The prostate and genitourinary group had 5.74 SSIs per 100 robot-assisted procedures (95% confidence interval [CI], 2.81–11.37), compared with 0.85 SSIs per 100 open procedures from national data. The gynecologic group had 10.00 SSIs per 100 procedures (95% CI, 2.79–30.10), compared with 1.72 SSIs per 100 open procedures. The colon and herniorrhaphy groups had 33.33 SSIs per 100 procedures (95% CI, 9.68–70.00) and 37.50 SSIs per 100 procedures (95% CI, 13.68–69.43), respectively, compared with 5.88 and 1.62 SSIs per 100 open procedures from national data. Patients with a clean-contaminated wound developed 6.1 SSIs per 100 procedures (95% CI, 3.5–10.3), compared with 2.59 SSIs per 100 open procedures. No significant differences in SSI rates were found for other groups.

Conclusions.

Increased incidence of SSI after some types of robot-assisted surgery compared with traditional open surgery may be related to the learning curve associated with use of the robot.
Predicting Bacteremia among Patients Hospitalized for Skin and Skin-Structure Infections: Derivation and Validation of a Risk Score
Authors: Lipsky Benjamin A. , Kollef Marin H. , Miller Loren G. , Sun Xiaowu , Johannes Richard S. , Tabak Ying P.
Published: June 2010

Objective.

Bacteremia is relatively common in patients with skin and skin-structure infection (SSSI) severe enough to require hospitalization. We used selected demographic and clinical characteristics easily assessable at initial evaluation to develop a model for the early identification of patients with SSSI who are at higher risk for bacteremia.

Participants.

A large database of adults hospitalized with SSSI at 97 hospitals in the United States during the period from 2003 through 2007 and from whom blood samples were obtained for culture at admission.

Methods.

We compared selected candidate predictor variables for patients shown to have bacteremia and patients with no demonstrated bacteremia. Using stepwise logistic regression to identify independent risk factors for bacteremia, we derived a model by using 75% of a randomly split cohort, converted the model coefficients into a risk score system, and then we validated it by using the remaining 25% of the cohort.

Results.

Bacteremia was documented in 1,021 (11.7%) of the 8,747 eligible patients. Independent predictors of bacteremia (P<.001) were infected device or prosthesis, respiratory rate less than 10 or more than 29 breaths per minute, pulse rate less than 49 or more than 125 beats per minute, temperature less than 35.6°C or at least 38.0°C, white blood cell band percentage of 7% or more, white blood cell count greater than 11 x 109/L, healthcare-associated infection, male sex, and older age. The bacteremia rates ranged from 3.7% (lowest decile) to 30.6% (highest decile) (P< .001). The model C statistic was 0.71; the Hosmer-Lemeshow testPvalue was .36, indicating excellent model calibration.

Conclusions.

Using data available at hospital admission, we developed a risk score that differentiated SSSI patients at low risk for bacteremia from patients at high risk. This score may help clinicians identify patients who require more intensive monitoring or antimicrobial regimens appropriate for treating bacteremia.
Observer Bias in Hand Hygiene Compliance Reporting
Authors: Dhar Sorabh , Tansek Ryan , Toftey Elizabeth A. , Dziekan Beth A. , Chevalier Thomas C. , Bohlinger Connie G. , Fitch Michelle , Flanagan Margaret E. , Chopra Teena , Marchaim Dror , Kaye Keith S.
Published: June 2010

Differences in reported hand hygiene compliance rates were assessed on the basis of the unit affiliation of observers. In 2 hospitals, unit-based observers more often reported higher compliance rates than did non-unit-based observers (79% vs 58.6%; difference, 20.4%; P<.001). Nonstandardized data collection methods contribute to the variability in hand hygiene compliance rates.
Large area Schottky diodes of ZnO films fabricated on platinum layer by pulsed-laser deposition
Authors: Li Y Z , Li X M , Yang C , Gao X D , He Y
Published: June 2010

Large area Schottky diode with novel inverted vertical metal–semiconductor–metal type of structure (Pt/Ti/ZnO/Pt/SiO2/Si) was demonstrated. The effects of crystallinity and native defects of ZnO films on the performance of Schottky diodes were investigated. Through oxygen plasma and post-annealing, the barrier height of Schottky diodes was dramatically enhanced, and the reverse leakage current was reduced by over six orders of magnitude. The obtained Schottky diodes with best performance of Schottky rectification exhibit the barrier height of 0.88 eV, and low reverse leakage current of 4.25 × 10−8 A cm−2 under reverse bias voltage of −2 V. The novel structure was promising for the application of high performance opt-electrical devices.
Dynamical plasma study during CaCu3Ti4O12 and Ba0.6Sr0.4TiO3 pulsed laser deposition by local thermodynamic equilibrium modelling
Authors: Lagrange J F , Hermann J , Wolfman J , Motret O
Published: June 2010

We performed space- and time-resolved plasma diagnostics during pulsed laser deposition of CaCu3Ti4O12 (CCTO) and Ba0.6Sr0.4TiO3 (BSTO) thin films. A KrF excimer laser irradiation at 248 nm with 25 ns pulse duration irradiates targets with a fluence varying from 1 to 2 J cm−2 under an oxygen pressure varying from 5 to 30 Pa. The plasma is shown to be optically thick and strongly non-uniform during the early expansion stage and the resonance lines Ca II 393 and 396 nm are strongly self-reversed during this time. Plasma temperature, electron density and relative elemental concentrations were obtained by comparing the experimental emission spectra with the spectral radiance computed for a non-uniform plasma in local thermal equilibrium. In this way, it was possible to evaluate very low concentrations of pollutants present in irradiated samples.
THEORY OF DISPERSED FIXED-DELAY INTERFEROMETRY FOR RADIAL VELOCITY
EXOPLANET SEARCHES
Authors: van Eyken Julian C. , Ge Jian , Mahadevan Suvrath
Published: June 2010

The dispersed fixed-delay interferometer (DFDI) represents a new instrument
concept for high-precision radial velocity (RV) surveys for extrasolar planets.
A combination of a Michelson interferometer and a medium-resolution
spectrograph, it has the potential for performing multi-object surveys, where
most previous RV techniques have been limited to observing only one target at a
time. Because of the large sample of extrasolar planets needed to better
understand planetary formation, evolution, and prevalence, this new technique
represents a logical next step in instrumentation for RV extrasolar planet
searches, and has been proven with the single-object Exoplanet Tracker (ET) at
Kitt Peak National Observatory, and the multi-object W. M. Keck/MARVELS
Exoplanet Tracker at Apache Point Observatory. The development of the ET
instruments has necessitated fleshing out a detailed understanding of the
physical principles of the DFDI technique. Here we summarize the fundamental
theoretical material needed to understand the technique and provide an overview
of the physics underlying the instrument's working. We also derive some useful
analytical formulae that can be used to estimate the level of various sources of
error generic to the technique, such as photon shot noise when using a fiducial
reference spectrum, contamination by secondary spectra (e.g., crowded sources,
spectroscopic binaries, or moonlight contamination), residual interferometer
comb, and reference cross-talk error. Following this, we show that the use of a
traditional gas absorption fiducial reference with a DFDI can incur significant
systematic errors that must be taken into account at the precision levels
required to detect extrasolar planets.
RTM3, Which Controls Long-Distance Movement of Potyviruses, Is a Member of a New Plant Gene Family Encoding a Meprin and TRAF Homology Domain-Containing Protein
Authors: Cosson Patrick , Sofer Luc , Hien Le Quang , Léger Valérie , Schurdi-Levraud Valérie , Whitham Steven A. , Yamamoto Miki L. , Gopalan Suresh , Le Gall Olivier , Candresse Thierry , Carrington James C. , Revers Frédéric
Published: June 2010

Restriction of long-distance movement of several potyviruses in Arabidopsis (Arabidopsis thaliana) is controlled by at least three dominant restricted TEV movement (RTM) genes, named RTM1, RTM2, and RTM3. RTM1 encodes a protein belonging to the jacalin family, and RTM2 encodes a protein that has similarities to small heat shock proteins. In this article, we describe the positional cloning of RTM3, which encodes a protein belonging to an undescribed protein family of 29 members that has a meprin and TRAF homology (MATH) domain in its amino-terminal region and a coiled-coil domain at its carboxy-terminal end. Involvement in the RTM resistance system is the first biological function experimentally identified for a member of this new gene family in plants. Our analyses showed that the coiled-coil domain is not only highly conserved between RTM3-homologous MATH-containing proteins but also in proteins lacking a MATH domain. The cluster organization of the RTM3 homologs in the Arabidopsis genome suggests the role of duplication events in shaping the evolutionary history of this gene family, including the possibility of deletion or duplication of one or the other domain. Protein-protein interaction experiments revealed RTM3 self-interaction as well as an RTM1-RTM3 interaction. However, no interaction has been detected involving RTM2 or the potyviral coat protein previously shown to be the determinant necessary to overcome the RTM resistance. Taken together, these observations strongly suggest the RTM proteins might form a multiprotein complex in the resistance mechanism to block the long-distance movement of potyviruses.
Topical 5‐aminolevulinic acid photodynamic therapy for recalcitrant facial flat wart in Chinese subjects
Authors: LIN Mao‐Ying , XIANG Lei‐Hong
Published: June 2010

The facial flat wart (verruca plana) is not only a contagious viral disease, but also causes a disturbing cosmetic problem. Because 5‐aminolevulinic acid photodynamic therapy has successfully treated human papilloma virus‐related diseases, we employed 20% 5‐aminolevulinic acid and a light emitting diode on three recalcitrant facial flat wart patients. Most lesions achieved complete remission after three or four sessions. However, a few non‐elevated lesions did not respond to this method. An ablative therapeutic mode is required in addition to 5‐aminolevulinic acid photodynamic therapy in such lesions. Therefore, we utilized an Er:YAG laser and 20% 5‐aminolevulinic acid photodynamic therapy for one session and achieved an excellent result. Patients should be informed of the possible side‐effects of this treatment, such as erythema, exfoliation and post‐inflammatory hyperpigmentation, and the requirement for sun protection.
Carotid artery intima media thickness associates with skin autofluoresence in non‐diabetic subjects without clinically manifest cardiovascular disease
Authors: Lutgers Helen L. , Graaff Reindert , De Vries Rindert , Smit Andries J. , Dullaart Robin P. F.
Published: June 2010

Eur J Clin Invest 2010; 40 (9): 812–817

Background  Skin autofluorescence (skin AF) is determined in part by accumulation of advanced glycation end products. Increased skin AF was shown previously to predict cardiovascular events independently of conventional risk factors. We determined the association of carotid artery intima media thickness (IMT), a marker of subclinical cardiovascular disease, with skin AF in subjects without diabetes or clinically manifest cardiovascular disease.

Methods  In a cross‐sectional observational study, IMT, skin AF, lipids and apolipoproteins, C‐reactive protein (CRP), insulin resistance and paraoxonase‐1 activity were measured in 59 non‐smoking, non‐obese subjects without diabetes mellitus and cardiovascular disease (32 women; 12 subjects with metabolic syndrome (MetS)).

Results  In univariate analyses, skin AF was correlated with IMT (r = 0·265, P = 0·042), but not significantly with clinical factors, (apo)lipoproteins, CRP, insulin resistance and paraoxonase‐1. In multiple linear regression analyses, IMT was determined independently by age (β = 0·549, P < 0·001), apo B (β = 0·236, P = 0·022) and skin AF (β = 0·216, P = 0·035). IMT was also associated with skin AF (β = 0·213, P = 0·046) in a model which included the presence of MetS.

Conclusions  IMT is positively related to skin AF, independently of clinical factors, (apo)lipoproteins and MetS, suggesting that skin AF represents a determinant of subclinical atherosclerosis. Increased skin AF may reflect early abnormalities in processes involved in atherosclerosis development.
Associated costs and benefits of a defended phenotype across multiple environments
Authors: Moran Daniel T. , Dias Gustavo M. , Marshall Dustin J.
Published: June 2010

1. Many organisms respond to threats such as stress and predation by expressing a defended phenotype (phenotypic plasticity) or inducing the expression of a defended phenotype in offspring (transgenerational phenotypic plasticity). While defended phenotypes can increase resistance to a predator or stress, in the absence of the inducing agent defended phenotypes often have poorer performance. Producing a defended phenotype unnecessarily has been termed a phenotype‐environment mismatch.

2. Most studies have focused on the benefits of a defended phenotype along a single environmental gradient (i.e. the presence/absence of the inducing agent) but in nature, organisms must face conditions that vary across a number of environmental gradients simultaneously. By focusing on the costs and benefits of a defended phenotype in a single dimension alone we risk underestimating the strength and likelihood of phenotype‐environment mismatches.

3. For the marine bryozoan Bugula neritina, we examined the performance of individuals with an induced, defended phenotype (pollution resistance) relative to individuals with an undefended phenotype across a number of different environments. We found that individuals with the defended phenotype were more sensitive to osmotic stress, but surprisingly, were less susceptible to predation than individuals with the undefended phenotype.

4. Our findings suggest that the costs and benefits associated with expressing a defended phenotype are more complex than previously realized because the full consequences of induced phenotypes are only unmasked when performance in multiple environments is examined.
Can selection on nest size from nest predation explain the latitudinal gradient in clutch size?
Authors: Biancucci Luis , Martin Thomas E.
Published: June 2010

1. Latitudinal variation in clutch sizes of birds is a well described, but poorly understood pattern. Many hypotheses have been proposed, but few have been experimentally tested, and none have been universally accepted by researchers.

2. The nest size hypothesis posits that higher nest predation in the tropics favours selection for smaller nests and thereby constrains clutch size by shrinking available space for eggs and/or nestlings in the nest. We tested this hypothesis with an experiment in a tropical forest and a comparative study between temperate and tropical field sites.

3. Specifically, we tested if: (i) predation increased with nest size; (ii) tropical birds had smaller nests controlled for body size; and (iii) clutch size was explained by nest size controlled for body size.

4. Experimental swapping of nests of different sizes showed that nest predation increased with nest size in the tropical site. Moreover, nest predation rates were higher in species with larger nests in both sites. However, nest size, corrected for body mass and phylogeny, did not differ between sites and was not related to clutch size between sites.

5. Hence, nest predation can exert selection on nest size as predicted by the hypothesis. Nest size increased with adult body mass, such that adult size might indirectly influence reproductive success through effects on nest size and nest predation risk. Ultimately, however, selection from nest predation on nest size does not explain the smaller clutch sizes typical of the tropics.
Use of itraconazole and either lime sulphur or Malaseb Concentrate Rinse®to treat shelter cats naturally infected withMicrosporum canis: an open field trial
Authors: Newbury Sandra , Moriello Karen A. , Kwochka Kenneth W. , Verbrugge Maria , Thomas Chester
Published: June 2010

In an open non‐randomized study, 90 cats with severe dermatophytosis were treated with 21 days of oral itraconazole at 10 mg/kg and one of three topical antifungal rinses applied twice weekly: lime sulphur (LSO); reformulated lime sulphur with an odour‐masking agent (LSR); or a 0.2% miconazole nitrate and 0.2% chlorhexidine gluconate rinse (MC). Weekly examinations and fungal cultures were used to monitor the cats’ response to therapy. If at day 42 of treatment cats were still strongly fungal culture positive and/or developing new lesions, they were retreated with oral itraconazole and LSO. Cats were not prevented from licking the solutions and none developed oral ulcerations. Thirty‐one cats were treated with LSO, 27 with LSR and 32 with MC. The median number of days to cure was 30 (range 10–69 days) and 34 (range 23–80 days) for LSO and LSR, respectively. Thirty‐two cats were treated with MC, and 13 of 32 cats required repeat treatment because of persistent culture‐positive status and development of new lesions. Median number of days of treatment for the 19 cats that cured with MC was 48 (range 14–93 days). When the number of days to cure was compared between the groups, there was a significant difference between cats treated with LSO and LSR (P = 0.029) and cats treated with LSO and MC (P = 0.031), but no significant difference between the number of days to cure for cats treated with LSR and MC (P = 0.91).