bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristic noise features in light transmission across membrane protein undergoing photocycle
Authors: Das Anshuman. J. , Mukhopadhyay Sabyasachi , Narayan K. S.
Published: February 2011

We demonstrate a technique based on noise measurements which can be utilized to study dynamical processes in protein assembly. Direct visualization of dynamics in membrane protein system such as bacteriorhodopsin (bR) upon photostimulation are quite challenging. bR represents a model system where the stimulus-triggered structural dynamics and biological functions are directly correlated. Our method utilizes a pump-probe near field microscopy method in the transmission mode and involves analyzing the transmittance fluctuations from a finite size of molecular assembly. Probability density distributions indicating the effects of finite size and statistical correlations appear as a characteristic frequency distribution in the noise spectra of bR whose origin can be traced to photocycle kinetics. Valuable insight into the molecular processes were obtained from the noise studies of bR and its mutant D96N as a function of external parameters such as temperature, humidity or presence of an additional pump source.
Photoelectron spectroscopic study of the negative ions of 4-thiouracil and 2,4-dithiouracil
Authors: Li Xiang , Chen Jing , Bowen Kit H.
Published: February 2011

We report the photoelectron spectra of the negative ions of 4-thiouracil (4-TU)− and 2,4-dithiouracil (2,4-DTU)−. Both of these spectra are indicative of valence anions, and they are each dominated by a single broad band with vertical detachment energies of 1.05 and 1.4 eV, respectively. Complementary calculations by Dolgounitcheva, Zakrzewski, and Ortiz (see companion paper) are in accord with our experimental results and conclude that the (4-TU)− and (2,4-DTU)− anions, reported herein, are valence anions of canonical 4-thiouracil and canonical dithiouracil. Comparisons among the anions and corresponding neutrals of 4-thiouracil, 2,4-dithiouracil, 5-chlorouracil, 5-fluorouracil, and uracil itself show that both sulfur and halogen modifications of uracil give rise to significant changes in the electronic structure. The electron affinities of the first four are all substantially larger than that of the canonical uracil.
Electron propagator and coupled-cluster calculations on the photoelectron spectra of thiouracil and dithiouracil anions
Authors: Dolgounitcheva O. , Zakrzewski V. G. , Ortiz J. V.
Published: February 2011

Electron affinities, vertical electron detachment energies, and isomerization energies of 4-thiouracil, 2-thiouracil, and 2,4-dithiouracil and their valence anions have been calculated with ab initio electron propagator and other many-body methods. Anions in which protons have been transferred to the C5 from the N1 or N3 ring positions have been considered, but the canonical forms are most stable for the 4-thiouracil and 2,4-dithiouracil anions. Electron affinities of 0.61, 0.26, and 0.87 eV have been determined for 4-thiouracil, 2-thiouracil, and 2,4-dithiouracil, respectively. Electron propagator calculations on the canonical anions yield vertical electron detachment energies that are in close agreement with experimental peaks at 1.05, 3.21, and 3.32 eV for 4-thiouracil and at 1.4 eV for 2,4-dithiouracil.
Photoconductivity in inverse silicon opals enhanced by slow photon effect: Yet another step towards optically amplified silicon photonic crystal solar cells
Authors: Suezaki Takashi , Yano Hiroshi , Hatayama Tomoaki , Ozin Geoffrey A. , Fuyuki Takashi
Published: February 2011

While silicon photonic crystals have promised revolutionary advances in the field of optical telecommunications and optical computing, it has only recently been realized that their prowess to trap and slow photons could potentially improve the efficiency of silicon solar cells. In this work, spectral responses for the electrical properties of inverse silicon opals are evaluated and show a correlation with photonic bandgaps. In particular, a sign of the enhanced photoelectric generation by the slow photon effect is observed at the edges of photonic bandgaps.
Mechanism for the direct electron injection from Al cathode to the phosphine oxide type electron transport layer
Authors: Jeon Soon Ok , Yook Kyoung Soo , Lee Jun Yeob , Park Soon Mi , Won Kim Jeong , Kim Ji-Hoon , Hong Jong-Am , Park Yongsup
Published: February 2011

A high efficiency blue fluorescent organic light-emitting diode without LiF electron injection layer was developed. Aluminum electrode was directly deposited on a phosphine oxide type electron transport layer and the observed quantum efficiency was as high as 6.13%. The ultraviolet photoemission spectroscopy data clearly indicated that the electron injection barrier (the offset between Al Fermi level and the lowest unoccupied molecular orbital of the organic layer) is less than 0.1 eV, which led us to believe that more efficient electron injection through the lower barrier is mainly responsible for the high efficiency.
Electric field concentration in the vicinity of the interface between anode and degraded BaTiO3-based ceramics in multilayer ceramic capacitor
Authors: Okamoto Takafumi , Kitagawa Shuji , Inoue Noriyuki , Ando Akira
Published: February 2011

The electric field distribution of degraded dielectric layers in multilayer ceramic capacitors (MLCCs) was investigated by Kelvin probe force microscopy (KFM) to clarify the insulation degradation mechanism in MLCCs. For the degraded dielectric layers, the electric field was found to be concentrated near the anodes. This concentration easily moved to the opposite side with a reversal of the applied voltage of 5 V (13 kV/cm) during KFM measurement at room temperature. On the other hand, electric field concentrations and electric field distributions did not change in fresh MLCCs, indicating that the electric field concentrations easily transfer near higher-potential interfaces between electrodes and ceramics only in degraded MLCCs. These facts suggest that Schottky barriers would be formed in degraded MLCCs. The KFM technique discussed in this work is a very useful tool for measuring the surface potential and helps clarify the local electric field concentration near the electrodes.
Role of nonradiative recombination centers and extended defects in nonpolar GaN on light emission efficiency
Authors: Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Amano H. , Pearton S. J. , Lee I.-H. , Sun Q. , Han J. , Karpov S. Yu.
Published: February 2011

The correlation of integrated microcathodoluminescence efficiency with crystalline quality and deep trap density of nonpolar GaN films grown by metal organic chemical vapor deposition on semi-insulating 6H-m-SiC or r-sapphire is analyzed. The results suggest a strong influence of nonradiative recombination centers whose concentration decreases with decreased density of extended defects. Electron traps with energy levels at Ec−0.6 eV and which pin the Fermi level in films with high defect density are the most likely candidates for the decrease in light emission efficiency in nonpolar GaN.
Near-infrared emission from Eu–Yb doped silicate glasses subjected to thermal reduction
Authors: Smedskjaer Morten M. , Qiu Jianrong , Wang John , Yue Yuanzheng
Published: February 2011

Quantum cutting (QC) is a promising approach for enhancing the energy conversion efficiency of solar cells since it allows for conversion of one ultraviolet photon from the sun into two near-infrared photons with energy comparable to the band gap of silicon solar cells. We find that QC can occur by cooperative energy transfer from Eu2+ to Yb3+ in soda-lime-silicate glasses subjected to thermal reduction around the glass transition temperature. Besides the QC effect, the thermal reduction results in improvement of surface performances, e.g., hardness. This synergy effect potentially makes the thermally reduced glass an ideal solar cell substrate material.
Altered Spatial Frequency Content in Paintings by Artists with Schizophrenia
Authors: Graham Daniel , Meng Ming
Published: February 2011

While it is difficult to imagine the way someone with mental illness perceives the world, paintings produced by mental illness sufferers with artistic talents offer a hint of this experience. Here we analyze these images in terms of statistics related to low-level visual processing. It is known that art in general possesses regular spatial frequency amplitude spectra, probably due to factors including luminance compression, approximation of natural scene spatial statistics, media, and aesthetics. Whatever the contributions of those factors may be, would the same ones apply for artists with schizophrenia? We find that spatial frequency content in paintings by five artists with schizophrenia or schizoaffective disorder is significantly different from that found in a large sample of art by painters without schizophrenia, while other basic spatial and intensity statistics are not different for the two groups. In particular, amplitude spectrum slopes are significantly steeper for paintings by artists with schizophrenia. A separate study of the works of one artist diagnosed with schizoaffective disorder confirmed these findings and showed no effect of medication type on amplitude spectrum slope. We suggest that these results support the notion that people with schizophrenia show decreased contrast sensitivity at low spatial frequencies. If people with schizophrenia cannot perceive low frequencies at the same level of contrast as that at which healthy individuals can, it follows that on average they will portray such components with higher contrast, resulting in steeper spectra.
Two ground state isoforms and a chromophore

D

-ring photoflip triggering extensive intramolecular changes in a canonical phytochrome
Authors: Song Chen , Psakis Georgios , Lang Christina , Mailliet Jo , Gärtner Wolfgang , Hughes Jon , Matysik Jörg
Published: February 2011

Phytochrome photoreceptors mediate light responses in plants and in many microorganisms. Here we report studies using
1
H–
13
C magic-angle spinning NMR spectroscopy of the sensor module of cyanobacterial phytochrome Cph1. Two isoforms of the red-light absorbing Pr ground state are identified. Conclusive evidence that photoisomerization occurs at the C15-methine bridge leading to a
β
-facial disposition of the ring

D

is presented. In the far-red-light absorbing Pfr state, strong hydrogen-bonding interactions of the

D

-ring carbonyl group to Tyr-263 and of N24 to Asp-207 hold the chromophore in a tensed conformation. Signaling is triggered when Asp-207 is released from its salt bridge to Arg-472, probably inducing conformational changes in the tongue region. A second signal route is initiated by partner swapping of the

B

-ring propionate between Arg-254 and Arg-222.
In vivo demonstration that α-synuclein oligomers are toxic
Authors: Winner Beate , Jappelli Roberto , Maji Samir K. , Desplats Paula A. , Boyer Leah , Aigner Stefan , Hetzer Claudia , Loher Thomas , Vilar Marçal , Campioni Silvia , Tzitzilonis Christos , Soragni Alice , Jessberger Sebastian , Mira Helena , Consiglio Antonella , Pham Emiley , Masliah Eliezer , Gage Fred H. , Riek Roland
Published: February 2011

The aggregation of proteins into oligomers and amyloid fibrils is characteristic of several neurodegenerative diseases, including Parkinson disease (PD). In PD, the process of aggregation of α-synuclein (α-syn) from monomers, via oligomeric intermediates, into amyloid fibrils is considered the disease-causative toxic mechanism. We developed α-syn mutants that promote oligomer or fibril formation and tested the toxicity of these mutants by using a rat lentivirus system to investigate loss of dopaminergic neurons in the substantia nigra. The most severe dopaminergic loss in the substantia nigra is observed in animals with the α-syn variants that form oligomers (i.e., E57K and E35K), whereas the α-syn variants that form fibrils very quickly are less toxic. We show that α-syn oligomers are toxic in vivo and that α-syn oligomers might interact with and potentially disrupt membranes.
Practice‐based evidence in school‐based counselling
Authors: Hanley Terry , Sefi Aaron , Lennie Clare
Published: February 2011

Aims: Counsellors are becoming commonplace within the support structures of secondary schools. To date, research findings from practice‐based outcome studies suggest this is a positive move. There are, however, numerous limitations to this work, and this project aims to develop this existing body of literature. Method: Nine 13–15 year olds attending counselling in six school‐based services participated in the project – one individual withdrew. A standardised self‐report questionnaire (YP‐CORE) was collected at four intervals: (1) the point of referral; (2) the onset of counselling; (3) the completion of counselling; and, (4) a two‐month follow‐up. The change indicated in each of these phases is examined and reported here. Additionally, YP‐CORE was completed during each session. Findings: The YP‐CORE indicates an improvement in the well‐being of this small sample, while waiting for and attending therapy. Further examination of session‐by‐session data also highlights how pre‐ and post‐outcome data should not necessarily be viewed as linear in nature. Discussion: This is a small‐scale investigation and further work is needed in this area. It does, however, raise a number of issues regarding the complexity inherent in conducting outcome research that warrant further investigation.
Comparison of calorimetric plasma diagnostics in a plasma downstream reactor
Authors: Roth C , Bornholdt S , Zuber V , Sonnenfeld A , Kersten H , Rudolf von Rohr P
Published: February 2011

The energy influx in a non-equilibrium plasma in the afterglow of a plasma downstream reactor has been measured by two different calorimetric probe types. The radio frequency discharge is investigated for oxygen (10–100%)–argon (90–0%) mixtures at relatively high gas flow rates (750–3000 sccm) and pressures (100–350 Pa). The main process parameters influencing the energy influx are the plasma power, the system pressure and the total gas flow rate. Even though the size, geometry and material composition of the used probe types are different, comparable energy flux values are achieved. Depending on the process parameters, energy fluxes between around 100 and 3500 W m−2 are found and the variation of the pressure and total gas flow rate suggests a highly flow-dependent plasma density distribution in the reactor.
Structural and impedance spectroscopy of pseudo-co-ablated (SrBi2Ta2O9)(1−x)–(La0.67Sr0.33MnO3)x composites
Authors: Maity S , Bhattacharya D , Ray S K
Published: February 2011

Composite thin films of (SrBi2Ta2O9)(1−x)–(La0.67Sr0.33MnO3)
x
are prepared for the first time using the pulsed-laser deposition technique with ablation occurring from two individual targets. X-ray diffraction and field-emission scanning electron microscopy reveal the formation of ferromagnetic La0.67Sr0.33MnO3 embedded in the ferroelectric SrBi2Ta2O9 phase. Complex impedance spectroscopy is carried out on the composite at different temperatures. Bulk resistance calculated from the complex impedance plot decreases with the increase in temperature up to 80 °C, an observation contradicting earlier results. However, the increase in resistivity of the La0.67Sr0.33MnO3 phase with temperature as the metal-to-insulator transition temperature (80 °C) is approached explains the observation. Also, the resistivity decreases with the increase in La0.67Sr0.33MnO3 content at a particular temperature. Electric modulus, dielectric spectroscopy and ac conductivity are used to study the transport property of the films. Activation energy, from the Arrhenius plot, is studied to discuss the conduction mechanism in the composite thin films.
Finite groups with Sylow 2-subgroups of class two. II
Authors: Gilman Robert , Gorenstein Daniel
Published: February 2011

In this paper we classify finite simple groups whose Sylow

2
2

-subgroups have nilpotence class two.
Comparison Between Potassium Bromate and Ozone as Flour Oxidants in Breadmaking
Authors: Sandhu Harkanwal P. S. , Manthey Frank A. , Simsek Senay , Ohm Jae‐Bom
Published: February 2011

The objective of this research was to compare the efficacy of potassium bromate with that of ozone treatment in wheat flour oxidation for breadmaking. In the first experiment, flour was treated with ozone at 1,500 ppm for 2, 4.5, 9, and 18 min. In the second experiment, flour was fully treated with ozone at 1,500 ppm for 45 min and then blended with control flour at concentrations of 10–30% (w/w). Flour became whiter and less yellow as ozonation time increased when compared to control flour. Size‐exclusion HPLC detected an increase in SDS buffer insoluble polymeric proteins in flour exposed to ozone. Bread made from flour treated with ozone for 2–4.5 min and bread that was made from flour blended with fully ozonated flour at 5 and 10% (w/w) was not significantly different for specific volume when compared with bread made with flour containing potassium bromate. Bread made from flour treated with ozone for 2, 4.5, and 9 min had a greater number of cells in crumb with larger loaf volumes than control flour. Results indicate that ozone treatment of flour could eliminate the need for potassium bromate in breadmaking.
Foaming of Differently Processed Oats: Role of Nonpolar Lipids and Tryptophanin Proteins
Authors: Kaukonen O. , Sontag‐Strohm T. , Salovaara H. , Lampi A.‐M. , Sibakov J. , Loponen J.
Published: February 2011

The baking properties of oats are poor, mainly due to the lack of gluten matrix and hence the surface properties of the aqueous phase are crucial for the gas retention in oat dough. Our aim was to study the composition and foaming properties of the water‐soluble fraction from differently processed oats. A water extract from kilned oats contained nonpolar triglycerides and had poor foaming properties, whereas removing lipids with hexane extraction improved the foaming capacity and foam stability. A water extract from supercritical carbon dioxide extracted oats (CO2‐oats) was free from nonpolar lipids and had good foam stability and excellent foaming capacity. Moreover, oat lipid‐binding proteins, tryptophanins, were highly concentrated in the CO2‐oats‐derived foam and apparently played an important role in the foam structure. Supplementing CO2‐oats extract with small quantities (<0.05%) of nonpolar lipids of oats destructed its foaming properties. In a preliminary baking trial, the addition of the nonpolar lipids to CO2‐oats and wheat‐starch‐based baking recipes resulted in baked goods with reduced volume. The study showed that nonpolar triglycerides were present in the aqueous phase of oat in a quantity that impaired foaming. Moreover, this was the first study showing that tryptophanins, lipid‐binding proteins of oats, were highly concentrated in foams prepared of oats free of water‐extractable nonpolar lipids. In conclusion, tryptophanins can be considered as the foam‐active proteins of oats that prevent the lipid‐induced destabilization of foam structures which could improve the baking properties of oats.
Quantitative and Temporal Definition of the Mla Transcriptional Regulon During Barley–Powdery Mildew Interactions
Authors: Moscou Matthew J. , Lauter Nick , Caldo Rico A. , Nettleton Dan , Wise Roger P.
Published: February 2011

Barley Mildew resistance locus a (Mla) is a major determinant of immunity to the powdery mildew pathogen, Blumeria graminis f. sp. hordei. Alleles of Mla encode cytoplasmic- and membrane-localized coiled-coil, nucleotide binding site, leucine-rich repeat proteins that mediate resistance when complementary avirulence effectors (AVRa) are present in the pathogen. Presence of an appropriate AVRa protein triggers nuclear relocalization of MLA, in which MLA binds repressing host transcription factors. Timecourse expression profiles of plants harboring Mla1, Mla6, and Mla12 wild-type alleles versus paired loss-of-function mutants were compared to discover conserved transcriptional targets of MLA and downstream signaling cascades. Pathogen-dependent gene expression was equivalent or stronger in susceptible plants at 20 h after inoculation (HAI) and was attenuated at later timepoints, whereas resistant plants exhibited a time-dependent strengthening of the transcriptional response, increasing in both fold change and the number of genes differentially expressed. Deregulation at 20 HAI implicated 16 HAI as a crucial point in determining the future trajectory of this interaction and was interrogated by quantitative analysis. In total, 28 potential transcriptional targets of the MLA regulon were identified. These candidate targets possess a diverse set of predicted functions, suggesting that multiple pathways are required to mediate the hypersensitive reaction.
Fusarium Head Blight of Cereals in Denmark: Species Complex and Related Mycotoxins
Authors: Nielsen L. K. , Jensen J. D. , Nielsen G. C. , Jensen J. E. , Spliid N. H. , Thomsen I. K. , Justesen A. F. , Collinge D. B. , Jørgensen L. N.
Published: February 2011

Quantitative real-time polymerase chain reaction differentiating 10 Fusarium spp. and Microdochium nivale or M. majus was applied to a total of 396 grain samples of wheat, barley, triticale, oat, and rye sampled across Denmark from 2003 to 2007, along with selected samples of wheat and barley from 1957 to 2000, to determine incidence and abundance of individual Fusarium spp. The mycotoxins deoxynivalenol (DON), nivalenol, zearalenone, T-2, and HT-2 were quantified using liquid chromatography–double mass spectrometry. Major differences in the Fusarium species complex among the five cereals as well as great yearly variation were seen. Fusarium graminearum, F. culmorum, and F. avenaceum were dominant in wheat, with DON as the dominant mycotoxin. F. langsethiae, F. culmorum, and F. avenaceum were dominant in barley and oat, leading to relatively high levels of the mycotoxins T-2 and HT-2. F. graminearum, F. culmorum, and F. avenaceum dominated in triticale and rye. The nontoxigenic M. nivale/majus were present in significant amounts in all cereal species. Wheat and barley samples from 1957 to 1996 exhibited no or very low amounts of F. graminearum, indicating a recent increase of this pathogen. Biomass and mycotoxin data exhibited good correlations between Fusarium spp. and their corresponding mycotoxins under field conditions.
Cervical Spinal Cord, Root, and Bony Spine Injuries
Authors: Hindman Bradley J. , Palecek John P. , Posner Karen L. , Traynelis Vincent C. , Lee Lorri A. , Sawin Paul D. , Tredway Trent L. , Todd Michael M. , Domino Karen B.
Published: February 2011

Background

The aim of this study was to characterize cervical cord, root, and bony spine claims in the American Society of Anesthesiologists Closed Claims database to formulate hypotheses regarding mechanisms of injury.

Methods

All general anesthesia claims (1970-2007) in the Closed Claims database were searched to identify cervical injuries. Three independent teams, each consisting of an anesthesiologist and neurosurgeon, used a standardized review form to extract data from claim summaries and judge probable contributors to injury.

Results

Cervical injury claims (n = 48; mean ± SD age 47 ± 15 yr; 73% male) comprised less than 1% of all general anesthesia claims. When compared with other general anesthesia claims (19%), cervical injury claims were more often permanent and disabling (69%; P < 0.001). In addition, cord injuries (n = 37) were more severe than root and/or bony spine injuries (n = 10; P < 0.001), typically resulting in quadriplegia. Although anatomic abnormalities (e.g., cervical stenosis) were often present, cord injuries usually occurred in the absence of traumatic injury (81%) or cervical spine instability (76%). Cord injury occurred with cervical spine (65%) and noncervical spine (35%) procedures. Twenty-four percent of cord injuries were associated with the sitting position. Probable contributors to cord injury included anatomic abnormalities (81%), direct surgical complications (24% [38%, cervical spine procedures]), preprocedural symptomatic cord injury (19%), intraoperative head/neck position (19%), and airway management (11%).

Conclusion

Most cervical cord injuries occurred in the absence of traumatic injury, instability, and airway difficulties. Cervical spine procedures and/or sitting procedures appear to predominate. In the absence of instability, cervical spondylosis was the most common factor associated with cord injury.
Ten-Year Follow-Up after Endovascular Repair of Traumatic Abdominal Aortic Rupture
Authors: Nicholls Stephen , Karmy-Jones Riyad
Published: February 2011

Blunt abdominal aortic injury is often associated with bowel injury that precludes operative repair because of the risk of graft infection. Endovascular repair has been reported but with limited follow-up. We present a case of a 15-year-old boy who underwent endovascular repair of blunt abdominal aortic rupture and whom we were able to follow up over a decade. Our experience with this case and three others, as well as the experience reported in the literature, suggests that endovascular repair is a reasonable option in the setting of concomitant bowel injury. The risk of over sizing, collapse, and migration may be less than that described for thoracic aortic injuries because there is no need to deploy the endograft across an angle.
Performance of Bioprosthetic Valves after Glycerol Dehydration, Ethylene Oxide Sterilization, and Rehydration
Authors: Fumoto Hideyuki , Chen Ji-Feng , Zhou Qun , Massiello Alex L. , Dessoffy Raymond , Fukamachi Kiyotaka , Navia Jose L.
Published: February 2011

Objective

Most commercially available bioprosthetic valves are stored in an aldehyde solution. We report a new alternative method: Self-expanding valves composed of dehydrated tissues with a high glycerin:water ratio can be collapsed into specially designed sheaths prior to sterilization for ease of delivery and storage.

Materials and Methods

Changes in tissue dimension of five samples of bovine pericardium were evaluated from baseline after glycerol treatment, air-drying, ethylene oxide (EtO) sterilization, and rehydration with water. Three valves fabricated from glutaraldehyde cross-linked tissues, including porcine pericardial tissue, bovine pericardial tissue, and porcine aortic valve, were dehydrated through a proprietary glycerin-based process, collapsed, placed within a catheter, EtO sterilized, stored for up to 212 days, and rehydrated with water. These valves were characterized in a mock circulation by mounting them at the inlet portion of a pneumatic pump before dehydration and after rehydration to evaluate the effects of dehydration and rehydration on the valve performance.

Results

Tissues treated with glycerol solution showed no significant changes in dimension from baseline after glycerol treatment, air-drying, EtO sterilization, and rehydration with water. In all the valves, pump flows reached the maximum output capacity of the pneumatic pump after rehydration without an increase in filling pressures as compared with those before dehydration.

Conclusions

This method for storing collapsible bioprosthetic valves using a proprietary glycerin-based process demonstrated excellent valve performance.
Performance of a Novel Dual-Electrode Bipolar Radiofrequency Ablation Device a Chronic Porcine Study
Authors: Voeller Rochus K. , Zierer Andreas , Schuessler Richard B. , Damiano Ralph J.
Published: February 2011

Objective

Over recent years, a variety of energy sources, including bipolar radiofrequency, have been used to replace the traditional incisions of the Cox-Maze procedure for the surgical treatment of atrial fibrillation (AF). The purpose of this study was to evaluate the safety and efficacy of a novel dual-electrode bipolar radiofrequency ablation device Synergy (Atricure, Inc., Cincinnati, OH USA) for AF in a chronic porcine model.

Methods

Six domestic pigs underwent a modified Cox-Maze IV procedure without cardiopulmonary bypass using the Synergy device. Animals survived for 30 days. Each pig then underwent induction of AF and was killed to remove the heart en bloc for histologic assessment. Each ablation line was dissected perpendicularly at 5-mm intervals to assess the lesion width, depth, and transmurality.

Results

All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins were documented by pacing acutely and at 30 days after the operation in all six animals. All animals failed to be induced in AF at 30 days. There was no gross evidence of intra-atrial thrombus formation or stricture of the pulmonary veins. All ablations (n = 209) examined were discrete, linear, and transmural, with a mean lesion width of 3.0 ± 0.7 mm and a mean lesion depth of 5.4 ± 3.3 mm. The mean ablation time was 16.3 ± 4.4 seconds, with a mean total energy delivery of 238 ± 170 J.

Conclusions

The Atricure Synergy was able to create reliable chronic transmural lesions of the modified Cox-Maze IV procedure on a porcine beating heart without cardiopulmonary bypass. The ablation lines were significantly wider when compared with its predecessor, the Isolator II.
Short-Term Outcomes after Thoracoscopic Lobectomy in Elderly Compared to Younger Patients
Authors: Meyerson Shari L. , Gustafson Monica R.
Published: February 2011

Objective

As the population continues to age, more benign and malignant lung lesions requiring surgical intervention are being identified in elderly patients. Historically, advanced age has been used to justify performing wedge resection rather than a lobectomy in elderly patients. The introduction of thoracoscopic surgery has resulted in improved short-term outcomes compared with thoracotomy. The objective of this study is to compare short-term outcomes of thoracoscopic lung resection in elderly patients to that in younger patients.

Methods

A retrospective review was performed of all patients undergoing thoracoscopic anatomic lobectomy without previous chemotherapy or radiation between April 2006 and April 2009. Patient charts were reviewed to determine risk factors, perioperative complications, and length of stay. Student's t test was used for comparison between groups.

Results

Over the period studied, 86 patients underwent thoracoscopic lobectomy. Forty of them were 70 years or older. Baseline pulmonary function testing showed an average FEV1 of 85% predicted (81% younger vs 90% older, P = nonsignificant). Median chest tube duration was 3 days and median length of stay was 4 days in both groups. The overall incidence of perioperative complications was 21% and was not different in the two groups (20% younger vs 22% older).

Conclusions

Elderly patients with good baseline pulmonary function tolerate thoracoscopic lobectomy as well as younger patients. Advanced age alone should not be considered a contraindication to lobectomy in the era of thoracoscopy. Elderly patients should be offered lobectomy rather than wedge resection on the basis of the same criteria used in younger patients.
Multivessel Awake Off-Pump Coronary Bypass Grafting Using Median Approach Technical Considerations
Authors: Watanabe Go , Ohtake Hiroshi , Tomita Shigeyuki , Yamaguchi Shojiro , Yashiki Noriyoshi , Kato Hiroki
Published: February 2011

Objective

Several reports of awake off-pump coronary artery bypass grafting (AOCAB) under high thoracic epidural anesthesia (TEA) for single-vessel grafts have been published, but few have described its application in multiple bypass procedures. We report the procedures and safety of AOCAB for multivessel disease.

Methods

Fifty-five multivessel AOCAB (52 men, 3 women; aged 68 ± 9.5 years) were performed at our hospital between 2003 and 2010. A medium sternotomy was made after TEA was established. During coronary artery anastomosis, a stabilizer and an apical suction device were used, and a coronary artery active perfusion system was used to maintain flow distal to the anastomosis. Pneumothorax due to pleural opening, when occurred, was repaired using Neoveil sheet and drainage tube.

Results

There was no operative death and no cerebral ischemia, cardiac arrhythmia, and chronic obstructive pulmonary disease. Operating time was 177 ± 35 minutes. Left internal thoracic artery was used in 55 anastomoses, right internal thoracic artery in 7, gastroepiploic artery in 17, radial artery in 48, and saphenous vein in 24. Time of anastomosis was 4.93 ± 0.92 minutes for left anterior descending coronary artery, 4.75 ± 1.21 minutes for circumflex artery, and 4.98 ± 1.02 minutes for right coronary artery. Intraprocedural pneumothorax occurred in 17 cases; 14 were repaired and nonintubated AOCAB was accomplished, 1 was intubated, and 2 had temporary assisted ventilation and laryngeal mask. Time to discharge was 15.5 ± 8.4 days.

Conclusions

Multivessel AOCAB under TEA is not only feasible but also safe. Multiple grafts can be harvested under TEA, and complete vascularization is possible under constant monitoring of blood pressure and consciousness.
Fluid Dynamic Investigation of the ATS 3F Enable Sutureless Heart Valve
Authors: Stühle Sebastian , Wendt Daniel , Hou Guojun , Wendt Hermann , Thielmann Matthias , Jakob Heinz , Kowalczyk Wojciech
Published: February 2011

Objective

Currently, sutureless heart valves (SHV) reveal good clinical results during aortic valve replacement. The aim of this study was to evaluate the fluid dynamics of the ATS 3F Enable SHV in the ascending aorta and their influence on the aortic wall in an in vitro setup.

Methods

A two-dimensional particle image velocimetry study with an image rate of 15 Hz was conducted to evaluate the fluid dynamics of the SHV in the aortic flow field. The prosthesis (diameter, 23 mm) was placed inside a silicone mock aorta under pulsatile flow conditions. Velocities, vorticity, and strain rate were obtained and calculated with a fixed frequency (70 Hz) at constant stroke volume (70 mL).

Results

3F Enable showed a jet flow type profile with a maximum velocity of 1.01 ± 0.13 m/s during peak flow phase (PFP). The jet flow was surrounded by ambilateral vortices with a slightly higher percentage of clockwise than counterclockwise vorticity (377 ± 57/s vs 389 ± 76/s), strain rate (370 ± 79/s for elongation vs — 370 ± 102/s for contraction) was nearly similar. The point-of-interest analysis revealed a higher velocity for bottom compared with upper aortic wall (0.28 ± 0.07 m/s vs 0.31 ± 0.06 m/s, P = 0.024). All values were lower during acceleration and deceleration phase compared with PFP.

Conclusions

The peak flow of the 3F Enable SHV seems to be little higher compared with native aortic valves, thus simulating nearly physiologic conditions. Vorticity and strain rate are high during PFP and low during other phases and might have an influence on the aortic wall as well.
Female bonobos use copulation calls as social signals
Authors: Clay Zanna , Pika Simone , Gruber Thibaud , Zuberbühler Klaus
Published: February 2011

During mating events, females of many primate species produce loud and distinct vocalizations known as ‘copulation calls’. The adaptive significance of these signals is considered to be in promoting the caller's direct reproductive success. Here, we investigated copulation calling in bonobos (
Pan paniscus
), a species in which females produce these vocalizations during sexual interactions with partners of both sexes. Females were more likely to call when mating with males than with females. We also observed a positive relationship between the likelihood of calling and partner rank, regardless of partner sex. Sexual activity generally increased with swelling size (an indicator of reproductive state) and, during their peak swelling, females called more with male than with female partners. Female bonobos are unusual among the non-human primates in terms of their heightened socio-sexuality. Our results suggest that in this species, copulation calls have undergone an evolutionary transition from a purely reproductive to a more general social function, reflecting the intrinsic evolutionary links between vocal behaviour and social cognition.
Synergy between social and private information increases foraging efficiency in ants
Authors: Czaczkes Tomer J. , Grüter Christoph , Jones Sam M. , Ratnieks Francis L. W.
Published: February 2011

Insect societies integrate many information sources to organize collective activities such as foraging. Many ants use trail pheromones to guide foragers to food sources, but foragers can also use memories to find familiar locations of stable food sources. Route memories are often more accurate than trail pheromones in guiding ants, and are often followed in preference to trail pheromones when the two conflict. Why then does the system expend effort in producing and acquiring seemingly redundant and low-quality information, such as trail pheromones, when route memory is available? Here we show that, in the ant
Lasius niger
, trail pheromones and route memory act synergistically during foraging; increasing walking speed and straightness by 25 and 30 per cent, respectively, and maintaining trail pheromone deposition, but only when used together. Our results demonstrate a previously undescribed major role of trail pheromones: to complement memory by allowing higher confidence in route memory. This highlights the importance of multiple interacting information sources in the efficient running of complex adaptive systems.
‘
Canis empathicus
’? A proposal on dogs' capacity to empathize with humans
Authors: Silva Karine , de Sousa Liliana
Published: February 2011

Empathy has long attracted the attention of philosophers and psychologists, and more recently, of evolutionary biologists. Interestingly, studies suggest that empathy is a phylogenetically continuous phenomenon, ranging across animals from automatic emotional activation in response to the emotions of others, to perspective-taking that becomes increasingly complex with increasing brain size. Although suggestions have been made that the domestic dog may have the capacity to empathize with humans, no discussion has yet addressed the topic, nor have experimental routes been proposed to further explore the level of emotional and cognitive processing underlying dogs' seemingly empathic behaviour towards humans. In this opinion piece, we begin by contextualizing our topic of interest within the larger body of literature on empathy. Thereafter we: (i) outline the reasons for why we believe dogs may be capable of empathizing with humans, perhaps even at some level beyond emotional contagion; (ii) review available evidence both pro and against our opinion; and (iii) propose routes for future studies to accurately address the topic. Also, we consider the use of dogs to further explore open questions regarding empathy in humans.
Impact of the experimental removal of lizards on Lyme disease risk
Authors: Swei Andrea , Ostfeld Richard S. , Lane Robert S. , Briggs Cheryl J.
Published: February 2011

The distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. Lizards (such as the western fence lizard;
Sceloporus occidentalis
) play a unique role in Lyme disease ecology in the far-western United States. Lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks (
Ixodes pacificus
—the vector for Lyme disease in that region) but are not competent reservoirs for the pathogen,
Borrelia burgdorferi
. Prior studies have suggested that the net effect of lizards is to reduce risk of human exposure to Lyme disease, a hypothesis that we tested experimentally. Following experimental removal of lizards, we documented incomplete host switching by larval ticks (5.19%) from lizards to other hosts. Larval tick burdens increased on woodrats, a competent reservoir, but not on deer mice, a less competent pathogen reservoir. However, most larvae failed to find an alternate host. This resulted in significantly lower densities of nymphal ticks the following year. Unexpectedly, the removal of reservoir-incompetent lizards did not cause an increase in nymphal tick infection prevalence. The net result of lizard removal was a decrease in the density of infected nymphal ticks, and therefore a decreased risk to humans of Lyme disease. Our results indicate that an incompetent reservoir for a pathogen may, in fact, increase disease risk through the maintenance of higher vector density and therefore, higher density of infected vectors.
Identification of a gene associated with avian migratory behaviour
Authors: Mueller Jakob C. , Pulido Francisco , Kempenaers Bart
Published: February 2011

Bird migration is one of the most spectacular and best-studied phenomena in behavioural biology. Yet, while the patterns of variation in migratory behaviour and its ecological causes have been intensively studied, its genetic, physiological and neurological control remains poorly understood. The lack of knowledge of the molecular basis of migration is currently not only limiting our insight into the proximate control of migration, but also into its evolution. We investigated polymorphisms in the exons of six candidate genes for key behavioural traits potentially linked to migration, which had previously been identified in several bird species, and eight control loci in 14 populations of blackcaps (Sylvia atricapilla), representing the whole range of geographical variation in migration patterns found in this species, with the aim of identifying genes controlling variation in migration. We found a consistent association between a microsatellite polymorphism and migratory behaviour only at one candidate locus: theADCYAP1gene. This polymorphism explained about 2.6 per cent of the variation in migratory tendency among populations, and 2.7–3.5% of variation in migratory restlessness among individuals within two independent populations. In all tests, longer alleles were associated with higher migratory activity. The consistency of results among different populations and levels of analysis suggests thatADCYAP1is one of the genes controlling the expression of migratory behaviour. Moreover, the multiple described functions of the gene product indicate that this gene might act at multiple levels modifying the shift between migratory and non-migratory states.
Weak conspecific feedbacks and exotic dominance in a species-rich savannah
Authors: MacDougall Andrew S. , Rillig Matthias C. , Klironomos John N.
Published: February 2011

Whether dominance drives species loss can depend on the power of conspecific self-limitation as dominant populations expand; these limitations can stabilize competitive imbalances that might otherwise cause displacement. We quantify the relative strength of conspecific and heterospecific soil feedbacks in an exotic-dominated savannah, using greenhouse trials and field surveys to test whether dominants are less self-suppressed, highly suppressive of others or both. Soil feedbacks can impact plant abundance, including invasion, but their implications for coexistence in invader-dominated systems are unclear. We found that conspecific feedbacks were significantly more negative than heterospecific ones for all species including the dominant invaders; even the rarest natives performed significantly better in the soils of other species. The strength of these negative feedbacks, however, was approximately 50 per cent stronger for natives and matched their field abundance—the most self-limited natives were rare and narrowly distributed. These results suggest that exotics dominate by interacting with natives carrying heavier conspecific feedback burdens, without cultivating either negative heterospecific effects that suppress natives or positive ones that accelerate their own expansion. These feedbacks, however, could contribute to coexistence because all species were self-limited in their own soils. Although the net impact of this feedback stabilization will probably interact with other factors (e.g. herbivory), soil feedbacks may thus contribute to invader dominance without necessarily being detrimental to species richness.
Scaling up ideals to freedom: are densities of red knots across western Europe consistent with ideal free distribution?
Authors: Quaintenne Gwenaël , van Gils Jan A. , Bocher Pierrick , Dekinga Anne , Piersma Theunis
Published: February 2011

Local studies have shown that the distribution of red knotsCalidris canutusacross intertidal mudflats is consistent with the predictions of an ideal distribution, but not a free distribution. Here, we scale up the study of feeding distributions to their entire wintering area in western Europe. Densities of red knots were compared among seven wintering sites in The Netherlands, UK and France, where the available mollusc food stocks were also measured and from where diets were known. We tested between three different distribution models that respectively assumed (i) a uniform distribution of red knots over all areas, (ii) a uniform distribution across all suitable habitat (based on threshold densities of harvestable mollusc prey), and (iii) an ideal and free distribution (IFD) across all suitable habitats. Red knots were not homogeneously distributed across the different European wintering areas, also not when considering suitable habitats only. Their distribution was best explained by the IFD model, suggesting that the birds are exposed to interference and have good knowledge about their resource landscape at the spatial scale of NW Europe, and that the costs of movement between estuaries, at least when averaged over a whole winter, are negligible.
Cooperation between dE2F1 and Yki/Sd defines a distinct transcriptional program necessary to bypass cell cycle exit
Authors: Nicolay Brandon N. , Bayarmagnai Battuya , Islam Abul B.M.M.K. , Lopez-Bigas Nuria , Frolov Maxim V.
Published: February 2011

The Hippo signaling pathway regulates organ size homeostasis, while its inactivation leads to severe hyperplasia in flies and mammals. The transcriptional coactivator Yorkie (Yki) mediates transcriptional output of the Hippo signaling. Yki lacks a DNA-binding domain and is recruited to its target promoters as a complex with DNA-binding proteins such as Scalloped (Sd). In spite of recent progress, an open question in the field is the mechanism through which the Yki/Sd transcriptional signature is defined. Here, we report that Yki/Sd synergizes with and requires the transcription factor dE2F1 to induce a specific transcriptional program necessary to bypass the cell cycle exit. We show that Yki/Sd and dE2F1 bind directly to the promoters of the Yki/Sd-dE2F1 shared target genes and activate their expression in a strong cooperative manner. Consistently, RBF, a negative regulator of dE2F1, negates this synergy and limits the overall level of expression of the Yki/Sd-dE2F1 target genes. Significantly, dE2F1 is needed for Yki/Sd-dependent full activation of these target genes, and a de2f1 mutation strongly blocks yki-induced proliferation in vivo. Thus, the Yki transcriptional program is determined through functional interactions with other transcription factors directly at target promoters. We suggest that such functional interactions would influence Yki activity and help diversify the transcriptional output of the Hippo pathway.