264 results on '"Bennett, S."'
Search Results
2. Long-term impact of paediatric tonsillectomy and adenotonsillectomy on the Paediatric Throat Disorders Outcome Test: a prospective observational study.
- Author
-
Bennett, S, Gao, J, Osen, E, and Myuran, T
- Subjects
- *
SCIENTIFIC observation , *CAREGIVERS , *ADENOIDECTOMY , *PEDIATRICS , *TONSILLECTOMY , *QUESTIONNAIRES , *DESCRIPTIVE statistics , *QUALITY of life , *PHARYNGITIS , *LONGITUDINAL method , *SYMPTOMS - Abstract
Background: The clinical value of tonsillectomy continues to cause much debate, despite tonsil disease representing a significant burden to patients, caregivers and healthcare systems. This study assessed the long-term effect of adenotonsillectomy or tonsillectomy on the Paediatric Throat Disorders Outcome Test ('T-14'), a validated tool used to objectively assess obstructive and infective symptoms in paediatric throat disorders. Methods: Patients aged under 16 years undergoing adenotonsillectomy or tonsillectomy were recruited consecutively from 2018 into our prospective observational study. The Paediatric Throat Disorders Outcome Test questionnaire was completed by the children's caregivers pre-operatively (n = 80), and at 21 days (n = 68) and 2 years (n = 66) post-operatively. Results: Significant reductions were noted in mean total Paediatric Throat Disorders Outcome Test scores at 21 days and 2 years post-operatively (p ≤ 0.003). Conclusion: Our results provide supporting evidence that paediatric adenotonsillectomy or tonsillectomy significantly improves quality of life up to two years post-operatively, and therefore remains a valuable use of healthcare resources. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Use of indocyanine green to facilitate safe biliary dissection in complex fields.
- Author
-
Snow, M. and Bennett, S.
- Published
- 2024
- Full Text
- View/download PDF
4. Efficacy of bacteriocin-based formula for reducing staphylococci, streptococci, and total bacterial counts on teat skin of dairy cows.
- Author
-
Bennett, S., Fliss, I., Ben Said, L., Malouin, F., and Lacasse, P.
- Subjects
- *
STREPTOCOCCUS , *DAIRY cattle , *BACTERIAL population , *MILK quality , *MASTITIS - Abstract
The use of teat dips is one of the most effective strategies to control mastitis by preventing new intramammary infections. Reducing bacterial load on teat skin helps control the spread of pathogens and spoilage and improves the quality of milk. The objective of this study was to evaluate the reduction of bacterial populations through the application of bacteriocin-based teat formulas. Teats of 12 Holstein cows received 2 different concentrations of bactofencin A, nisin, and reuterin alone or in combination, as well as iodine (positive control) and saline (negative control). Teat swabs were collected before and after application of teat formulas and analyzed for staphylococci, streptococci, and total bacteria counts. There were no differences for staphylococci, streptococci, and total bacterial counts for samples collected before application throughout the entire experiment. Reuterin-low and reuterin-high treatments reduced total bacterial count by 0.47 and 0.36 logs, respectively, whereas bactofencin A had no effect on any tested bacterial groups. Nisin-low treatment reduced staphylococci, streptococci, and total bacterial counts by 0.47, 0.30 and 0.50 logs, respectively. Nisin-high treatment resulted in 0.50, 0.50, and 0.47 log reduction for staphylococci, streptococci, and total bacterial counts. The bacteriocin consortium showed the highest reduction rates with 0.91, 0.54, and 0.90 log reductions obtained for staphylococci, streptococci, and total bacteria counts, respectively, for the low-concentration consortium. Similarly, the high-concentration consortium showed reduction rates with 0.95, 0.60, and 0.82 log reductions obtained for staphylococci, streptococci, and total bacteria counts, respectively. Thus, nisin and the bacteriocin consortium showed the most promise as a teat disinfectant by reducing staphylococci, streptococci, and total bacteria counts. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. The dynamic trophic architecture of open-ocean protist communities revealed through machine-guided metatranscriptomics.
- Author
-
Lambert, Bennett S., Groussman, Ryan D., Schatz, Megan J., Coesel, Sacha N., Durham, Bryndan P., Alverson, Andrew J., White, Angelicque E., and Armbrust, E. Virginia
- Subjects
- *
CRUISE industry , *OCEAN temperature , *MACHINE learning , *MARINE ecology , *GENE families , *PROTISTA - Abstract
Intricate networks of single-celled eukaryotes (protists) dominate carbon flow in the ocean. Their growth, demise, and interactions with other microorganisms drive the fluxes of biogeochemical elements through marine ecosystems. Mixotrophic protists are capable of both photosynthesis and ingestion of prey and are dominant components of open-ocean planktonic communities. Yet the role of mixotrophs in elemental cycling is obscured by their capacity to act as primary producers or heterotrophic consumers depending on factors that remain largely uncharacterized. Here, we develop and apply a machine learning model that predicts the in situ trophic mode of aquatic protists based on their patterns of gene expression. This approach leverages a public collection of protist transcriptomes as a training set to identify a subset of gene families whose transcriptional profiles predict trophic mode. We applied our model to nearly 100 metatranscriptomes obtained during two oceanographic cruises in the North Pacific and found community-level and population-specific evidence that abundant open-ocean mixotrophic populations shift their predominant mode of nutrient and carbon acquisition in response to natural gradients in nutrient supply and sea surface temperature. Metatranscriptomic data from ship-board incubation experiments revealed that abundant mixotrophic prymnesiophytes from the oligotrophic North Pacific subtropical gyre rapidly remodeled their transcriptome to enhance photosynthesis when supplied with limiting nutrients. Coupling this approach with experiments designed to reveal the mechanisms driving mixotroph physiology provides an avenue toward understanding the ecology of mixotrophy in the natural environment. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
6. Thyroidectomy without Radioiodine in Low-Risk Thyroid Cancer.
- Author
-
Tulchinsky, Mark, Greenspan, Bennett S., Gulec, Seza A., and McGoron, Anthony J.
- Subjects
- *
RELATIVE medical risk , *THYROIDECTOMY , *THYROID gland tumors , *PAPILLARY carcinoma , *IODINE radioisotopes - Published
- 2022
- Full Text
- View/download PDF
7. Strategies for the delay of surgery in the management of resectable hepatobiliary malignancies during the COVID-19 pandemic.
- Author
-
Bennett, S., Søreide, K., Gholami, S., Pessaux, P., Teh, C., Segelov, E., Kennecke, H., Prenen, H., Myrehaug, S., Callegaro, D., and Hallet, J.
- Subjects
- *
COVID-19 pandemic , *LIVER surgery , *GALLBLADDER cancer , *SURGERY , *LIVER metastasis , *OPERATING rooms - Abstract
Objective We aimed to review data about delaying strategies for the management of hepatobiliary cancers requiring surgery during the covid-19 pandemic. Background Given the covid-19 pandemic, many jurisdictions, to spare resources, have limited access to operating rooms for elective surgical activity, including cancer, thus forcing deferral or cancellation of cancer surgeries. Surgery for hepatobiliary cancer is high-risk and particularly resource-intensive. Surgeons must critically appraise which patients will benefit most from surgery and which ones have other therapeutic options to delay surgery. Little guidance is currently available about potential delaying strategies for hepatobiliary cancers when surgery is not possible. Methods An international multidisciplinary panel reviewed the available literature to summarize data relating to standard-of-care surgical management and possible mitigating strategies to be used as a bridge to surgery for colorectal liver metastases, hepatocellular carcinoma, gallbladder cancer, intrahepatic cholangiocarcinoma, and hilar cholangiocarcinoma. Results Outcomes of surgery during the covid-19 pandemic are reviewed. Resource requirements are summarized, including logistics and adverse effects profiles for hepatectomy and delaying strategies using systemic, percutaneous and radiation ablative, and liver embolic therapies. For each cancer type, the long-term oncologic outcomes of hepatectomy and the clinical tools that can be used to prognosticate for individual patients are detailed. Conclusions There are a variety of delaying strategies to consider if availability of operating rooms decreases. This review summarizes available data to provide guidance about possible delaying strategies depending on patient, resource, institution, and systems factors. Multidisciplinary team discussions should be leveraged to consider patient- and tumour-specific information for each individual case. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
8. Jet Noise Reduction in Co-Flowing Jets with Finite Lip Thickness.
- Author
-
Bennett, S. Kevin and Shankar, R. Naren
- Subjects
- *
JETS (Fluid dynamics) , *NOISE control , *MACH number , *ACOUSTIC radiation , *SOUND pressure - Abstract
Passive control for suppressing mixing noise from Co-Flowing Jets (CFJ) is presented in this study. The idea behind this is to reduce the convective Mach number of turbulent eddies that produce intense sound radiation. The present study analyses co-flowing jets with a bypass ratio of 6.3 and the primary nozzle lip thickness of 10 mm. The aim of the study is to find the jet noise level in finite lip thickness in co-flowing jets. CFJ with finite lip thickness forms a recirculation zone (in the near field). The secondary core and recirculation zone are shielding the primary core by reducing the jet noise. A single free jet with a diameter equal to that of a primary nozzle of co-flowing jet is also studied for comparison. The results show that co-flow jet with finite lip thickness of 10mm for various emission angles and the Overall Sound Pressure Level (OASPL) level gets reduced when compared with the single free jet. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
9. Measurement of the 13C(n,γ) thermal cross section via neutron irradiation and AMS.
- Author
-
Wright, T., Bennett, S., Heinitz, S., Köster, U., Mills, R., Soldner, T., Steier, P., Wallner, A., and Wieninger, T.
- Subjects
- *
NEUTRON irradiation , *RESEARCH reactors , *NEUTRON beams , *MASS spectrometers - Abstract
Ampoules of amorphous 99.5% enriched 13C were irradiated at the PF1b neutron beam line at the high-flux ILL research reactor in order to produce 14C atoms. The precise ratio of 14C/13C was subsequently measured at the VERA Accelerator Mass Spectrometer, allowing the 13C(n, γ )14C thermal cross section to be accurately determined. This is the first measurement of this cross section at sub-eV energies via this technique and the result of 1. 52 ± 0. 07 mb for the thermal cross section is in good agreement with other recent measurements which were performed via Prompt Gamma-ray Activation Analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Motility drives bacterial encounter with particles responsible for carbon export throughout the ocean.
- Author
-
Lambert, Bennett S., Fernandez, Vicente I., and Stocker, Roman
- Subjects
- *
PARTICLES , *OCEAN , *OCEAN color , *PHOTOSYNTHETIC bacteria , *PARTICLE size distribution , *CARBON fixation , *BOLTZMANN'S constant , *CARBON cycle - Published
- 2019
- Full Text
- View/download PDF
11. Adaptive designs in dermatology clinical trials: Current status and future perspectives.
- Author
-
Potvin, D., D'Angelo, P., Bennett, S., Jankicevic, J., and Bissonnette, R.
- Abstract
Current drug development strategies present many challenges that can impede drug approval by regulatory agencies. Alternative study models, such as adaptive trial designs, have recently sparked interest, as they provide a flexible and more efficient approach in conducting clinical trials. Adaptive trial designs offer several potential benefits over traditional randomized controlled trials, which include decrease in costs, reduced clinical development time and limiting exposure of patients to potentially ineffective treatments allowing completion of studies with fewer patients. This article explores the current use of adaptive trial designs in non‐oncologic skin diseases and highlights the most common types of adaptive designs used in the field. We also review the operational challenges and statistical considerations associated with such designs and propose clinical development strategies to successfully implement adaptive designs. The article also proposes instances where adaptive trial designs are particularly beneficial, and other situations where they may not be very useful. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Magnetic properties of GaMnAs nanodot arrays fabricated using porous alumina templates.
- Author
-
Bennett, S. P., Menon, L., and Heiman, D.
- Subjects
- *
SOLID state electronics , *ELECTRIC conductivity , *ALUMINUM oxide , *SEMICONDUCTOR industry , *CRYSTALS , *SOLID state physics - Abstract
Ordered arrays of GaMnAs magnetic semiconductor nanodots have been fabricated using anodic porous alumina templates as etch masks. The magnetic behavior is studied for prepared arrays with 40 nm dot diameter, 15 nm dot thickness, and 80 nm periodicity. The disklike nanodots exhibit an easy axis for fields applied in the radial direction and a hard axis in the smaller direction. In the radial direction superparamagnetism is observed with a blocking temperature of 30 K. The fabrication technique is convenient for preparing nanodot arrays of compound semiconductors that cannot be formed by self-assembly techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
13. Theranostic Nanoparticle Uptake in Patient Brain Tumors as Quantified by MP2RAGE T1 Mapping.
- Author
-
Bennett, S., Verry, C., Kaza, E., Miao, X., Berbeco, R.I., and Sudhyadhom, A.
- Subjects
- *
NANOPARTICLES , *BLOCH equations , *BRAIN tumors , *CONTRAST media , *RADIATION doses , *RADIOTHERAPY - Abstract
Modern radiation therapy techniques provide effective treatments for solid tumors, but there remain challenges with delivering high doses to elusive tumors without causing toxicity to surrounding normal tissue. Pre-clinical trials have demonstrated the theranostic properties of a recently developed gadolinium-based nanoparticle (Gd-NP). The first in-human clinical trial was conducted to assess the safety and dose tolerance of intravenous Gd-NPs in combination with whole brain radiotherapy and showed favorable results, including a significant correlation between tumor uptake and therapeutic response. The second, double-blinded, in-human clinical trial is underway in the US and aims to evaluate if brain-directed stereotactic radiation in conjunction with NPs will improve local tumor control compared to radiation alone. The current work investigates uptake patterns in brain tumors of 23 patients as quantified by magnetization prepared 2 rapid gradient echo (MP2RAGE) T1 mapping. A phantom containing eight vials of NP-saline solutions at varying concentrations was created to examine the relationship between NP concentration and longitudinal relaxation (T1, in seconds). This relationship is known as relaxivity and is dependent on the contrast agent, field strength and T1 mapping sequence. A 3T MAGNETOM Vida scanner and MP2RAGE sequence were used to image the phantom and MP2RAGE T1 maps were calculated using Bloch equations (QMRLab software). Relaxivity was determined and applied to 23 patient T1 maps (pre- and post- Gd-NP administration) to calculate uptake on an individual tumor basis. Theranostic NP uptake was calculated for every voxel in each of 129 brain metastases and examined for patterns in quantity and distribution. Average individual tumor uptake ranged from 0.02-0.12 mg/ml, where average overall uptake was equal to 0.05 mg/ml. A relationship between tumor diameter and mean NP concentration was observed and best represented by a power-based curve (R2 = 0.92). In contrast, patients with suspected placebo administration appeared to have no uptake and therefore no relationship with tumor diameter. The distribution of NP concentration within the tumor was also examined; on average, linear uptake profiles through tumor centroids (ant-post, left-right) demonstrated roughly gaussian patterns of uptake with lower concentrations at the tumor edges and higher concentrations at the tumor center. This pattern indicates robust tumor penetration and may have implications for amplifying radiation dose to hypoxic tumors. Gd-NP uptake in brain metastases can be quantified using MP2RAGE T1 mapping. Uptake was determined for each voxel in each tumor volume, where a gaussian pattern of spatial concentrations was observed. This analysis procedure will be applied to the full data set, when available, to evaluate the impact of NP uptake (in conjunction with radiation therapy) within individual patients and individual tumors. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
14. Magnetic interactions and interface properties in Co/Fe multilayers.
- Author
-
Agazzi, L., Bennett, S., Berry, F. J., Carbucicchio, M., Rateo, M., Ruggiero, G., and Turilli, G.
- Subjects
- *
INTERFACES (Physical sciences) , *ELECTRON beams , *REFLECTANCE , *HYSTERESIS loop - Abstract
Co/Fe multilayers with different layer thickness formed by electron beam evaporation in ultrahigh vacuum have been investigated by grazing incidence x-ray reflectivity (GIXRR) and alternating gradient force magnetometry. The interface thicknesses are lower than GIXRR uncertainty (∼ 1 nm), favoring a strong magnetic exchange interaction between the layers responsible for their single phase magnetic behavior. The hysteresis loops were interpreted as the result of two different magnetization processes related to the presence of an out-of-plane component of the magnetization. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
15. The Battle of the River Plate: Excerpts from the Diary of Surgeon Commander Jack Cussen RN, PMO of HMS EXETER.
- Author
-
Bennett, S. G.
- Subjects
- *
HISTORY of ships , *HISTORY of war , *LIFE expectancy , *REFLECTION (Philosophy) , *PSYCHOLOGY of military personnel , *SURGEONS , *PSYCHOSOCIAL factors , *DIARY (Literary form) - Published
- 2019
16. Pill identification: comparing the identification accuracy and error rates of Internet search engines and standard pill identification applications by entering visual characteristics.
- Author
-
Shenker, Bennett S., Turner, John C., and Brandspiegel, Heather T.
- Subjects
- *
AUDIOVISUAL materials , *PATIENT safety , *PHARMACY information services , *SEARCH engines , *DATA analysis ,RESEARCH evaluation - Abstract
Background: Proper identification of medications is important for patient safety. Many pill identification applications are available to help identify tablets/capsules but their accuracy varies. Internet search engines could be an alternative for identification. Aim: The hypothesis was that Internet search engines would perform as well as or better than pill identification applications in determining the name and dosage of medications. Methods: A set of images of 451 pills was prepared. Visual characteristics were entered into two Internet search engines and three pill identification applications. Head to head comparisons of correct identifications were made using McNemar's test. Results: No statistically significant difference was found in correct identifications between Google (93.6%) and Drugs.com (94.0%). Both Google and Drugs.com performed better than Bing (91.4%) at the p < 0.05 level. Drugs.com, Google and Bing all performed better than Pillbox (68.3%) and Epocrates (54.1%) at the p < 0.0001 level. Conclusion: Internet search engines perform well in pill identification and better than some dedicated pill identification applications. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. Present and future of target therapies and theranostics: Refining traditions and exploring new frontiers.
- Author
-
Hertz, Barbara and Greenspan, Bennett S.
- Subjects
- *
COMPANION diagnostics , *IODINE isotopes , *NUCLEAR fission , *RADIOISOTOPES - Abstract
Saul Hertz advanced the use of RAI to diagnose and successfully treat thyroid carcinoma as well as exploring the use of additional radioisotopes and hormones to treat other forms of cancer. Each of the 144 articles reviewed in "Present and future of target therapies and theranostics: refining traditions and exploring new frontiers-highlights from Annals of Nuclear Medicine 2021" are built on Saul Hertz's seminal work. [Extracted from the article]
- Published
- 2023
- Full Text
- View/download PDF
18. New smallest specimen of the pterosaur Pteranodon and ontogenetic niches in pterosaurs.
- Author
-
Bennett, S. Christopher
- Subjects
- *
PTEROSAURIA , *PTERANODON , *ONTOGENY , *ECOLOGICAL niche , *GEOLOGICAL formations - Abstract
A new juvenile specimen of Pteranodon from the Smoky Hill Chalk Member of the Niobrara Formation of western Kansas had an estimated wingspan in life of 1.76 m, ~45% smaller than the smallest previously known specimens, but does not differ in morphology from larger specimens. Its presence indicates that juveniles were capable of flying long distances, so it falsifies the interpretation of Pteranodon as growing rapidly to adult size under parental care before flying. Instead juveniles were precocial, growing more slowly to adult size while flying and feeding independently for several years before going to sea. Because juveniles are otherwise unknown in the Smoky Hill Chalk Member, they must have occupied different environments and ecological niches than adults; thus Pteranodon exhibited ontogenetic niches. Evidence is presented that most other pterosaurs (e.g., Rhamphorhynchus, Pterodactylus, Anhanguera) also exhibited various ontogenetic niches, which, along with their large body size, suggests that pterosaur taxonomic diversity was rather low, like that of crocodilians. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
19. Magnetic field response of doubly clamped magnetoelectric microelectromechanical AlN-FeCo resonators.
- Author
-
Bennett, S. P., Baldwin, J. W., Staruch, M., Matis, B. R., LaComb, J., van't Erve, O. M. J., Bussmann, K., Metzler, M., Gottron, N., Zappone, W., LaComb, R., and Finkel, P.
- Subjects
- *
ELECTRIC resonators , *MICROELECTROMECHANICAL systems , *ALUMINUM nitride , *IRON-cobalt alloys , *MAGNETOELECTRIC effect , *MAGNETIC field effects , *MAGNETIC sensors - Abstract
Magnetoelectric (ME) cantilever resonators have been successfully employed as magnetic sensors to measure low magnetic fields; however, high relative resolution enabling magnetometry in high magnetic fields is lacking. Here, we present on-chip silicon based ME microelectromechanical (MEMS) doubly clamped resonators which can be utilized as high sensitivity, low power magnetic sensors. The resonator is a fully suspended thin film ME heterostructure composed of an active magnetoelastic layer (Fe0.3Co0.7), which is strain coupled to a piezoelectric signal/excitation layer (AlN). By controlling uniaxial stress arising from the large magnetoelastic properties of magnetostrictive FeCo, a magnetically driven shift of the resonance frequency of the first fundamental flexural mode is observed. The theoretical intrinsic magnetic noise floor of such sensors reaches a minimum value of 35 pT/√Hz. This approach shows a magnetic field sensitivity of ~5 Hz/mT in a bias magnetic field of up to 120 mT. Such sensors have the potential in applications required for enhanced dynamic sensitivity in high-field magnetometry. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
20. Functional Analysis of the Glucan Degradation Locus in Caldicellulosiruptor bescii Reveals Essential Roles of Component Glycoside Hydrolases in Plant Biomass Deconstruction.
- Author
-
Conway, Jonathan M., McKinley, Bennett S., Seals, Nathaniel L., Hernandez, Diana, Khatibi, Piyum A., Poudel, Suresh, Giannone, Richard J., Hettich, Robert L., Williams-Rhaesa, Amanda M., Lipscomb, Gina L., Adams, Michael W. W., and Kelly, Robert M.
- Subjects
- *
FUNCTIONAL analysis , *GLUCANS , *HYDROLASES , *PLANT biomass , *POLYSACCHARIDES - Abstract
The ability to hydrolyze microcrystalline cellulose is an uncommon feature in the microbial world, but it can be exploited for conversion of lignocellulosic feedstocks into biobased fuels and chemicals. Understanding the physiological and biochemical mechanisms by which microorganisms deconstruct cellulosic material is key to achieving this objective. The glucan degradation locus (GDL) in the genomes of extremely thermophilic Caldicellulosiruptor species encodes polysaccharide lyases (PLs), unique cellulose binding proteins (ta_pirins), and putative posttranslational modifying enzymes, in addition to multidomain, multifunctional glycoside hydrolases (GHs), thereby representing an alternative paradigm for plant biomass degradation compared to fungal or cellulosomal systems. To examine the individual and collective in vivo roles of the glycolytic enzymes, the six GH genes in the GDL of Caldicellulosiruptor bescii were systematically deleted, and the extents to which the resulting mutant strains could solubilize microcrystalline cellulose (Avicel) and plant biomass (switchgrass or poplar) were examined. Three of the GDL enzymes, Athe_1867 (CelA) (GH9-CBM3-CBM3-CBM3-GH48), Athe_1859 (GH5-CBM3-CBM3-GH44), and Athe_1857 (GH10-CBM3-CBM3-GH48), acted synergistically in vivo and accounted for 92% of naked microcrystalline cellulose (Avicel) degradation. However, the relative importance of the GDL GHs varied for the plant biomass substrates tested. Furthermore, mixed cultures of mutant strains showed that switchgrass solubilization depended on the secretome-bound enzymes collectively produced by the culture, not on the specific strain from which they came. These results demonstrate that certain GDL GHs are primarily responsible for the degradation of microcrystalline cellulose-containing substrates by C. bescii and provide new insights into the workings of a novel microbial mechanism for lignocellulose utilization. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
21. Structural order and magnetic anisotropy transition in Co/Fe multilayers.
- Author
-
Carbucicchio, M., Bennett, S., Berry, F. J., Prezioso, M., Rateo, M., and Turilli, G.
- Subjects
- *
COPPER , *MAGNETISM , *ANISOTROPY , *MAGNETIZATION - Abstract
Co/Fe multilayers were electron-beam evaporated in ultrahigh vacuum onto quartz substrates keeping the Co layer thickness (10 nm) constant and changing that of Fe (10-30 nm). For Fe layer thicknesses up to 24 nm, the magnetization substantially lies in the film plane and shows a uniaxial magnetic anisotropy. The coercive field measured along the easy axis is ∼10 Oe, and the x-ray reflectivity patterns show a superlattice behavior. For a Fe layer thickness equal to 30 nm, the in-plane texture strongly decreases, the coercive field increases up to ∼100 Oe, the magnetization direction forms an out-of-plane angle of ∼36° and a stripe magnetic domain structure takes place. The observed in-plane anisotropy and the changing in the magnetic order as a function of the iron layer thickness is discussed and justified, assuming that the growth of the first Co layer occurs by the nucleation of ordered zones, influencing the subsequent layer order via exchange interaction. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
22. Quantifying Gadolinium-Based, Theranostic Nanoparticle Uptake in MR Images of Pancreatic Cancer.
- Author
-
Bennett, S., Hsu, S.H., Verry, C., Kaza, E., Miao, X., Keerthivasan, M.B., Mamon, H.J., Mak, R.H., Mancias, J.D., Cagney, D.N., Leeman, J.E., Sudhyadhom, A., and Berbeco, R.I.
- Subjects
- *
PANCREATIC cancer , *MAGNETIC resonance imaging , *INTRAVENOUS therapy , *SPINAL canal , *CANCER patients , *PANCREATIC tumors - Abstract
Nanomedicines are proving to be a viable option in improving radiotherapeutic benefits by amplifying the effects of radiotherapy. A recently developed, gadolinium (Gd) based theranostic agent has shown promise in the treatment of previously difficult to treat tumors. Here we examine, for the first time, uptake of this agent in patients with pancreatic cancer undergoing MR-guided adaptive radiotherapy. Data have been acquired from four patients with pancreatic cancer enrolled in a stereotactic MR-guided adaptive radiotherapy clinical trial utilizing Gd-based nanoparticles (Nano-SMART). This trial has nanoparticles intravenously infused prior to MR simulation scanning (3T and 0.35T) and again prior to the first fraction (of five daily fractions). Physician-drawn contours were delineated on an MRI-guided real-time on-table adaptive radiotherapy 0.35T planning bSSFP scan. T1 maps of the abdomen were produced on a 3T scanner (a fully-body MRI scanner, from a technology company) before and after nanoparticle administration, using a prototype Look-Locker T1 mapping sequence with 28-30 slices (3 mm thickness, 1 mm spacing) and 244 × 244 pixels (1.56 × 1.56mm). Pre- and post- nanoparticle T1 maps were registered to the 0.35T planning images. Nanoparticle concentrations within contour defined volumes were calculated from T1 maps using the measured change in T1 values and a previously determined relaxivity constant (8.9 mM−1s−1). Average concentrations were compared across patients and anatomical structures. The use of an MR-Linac for adaptive radiotherapy enabled examination of nanoparticle uptake over time. MRI scans (bSSFP) were captured at each fraction, processed for bias field correction and normalized to spinal canal volumes; a region previously determined to not have significant uptake. Adapted contours defined fraction-specific volumes which were examined for patterns in signal intensity (SI) over time. Average T1 values for all targeted volumes (CTV, GTV) dropped after nanoparticle infusion. The amount of uptake varied significantly amongst patients but similarly amongst structures, with a notable initial concentration in the liver and kidneys. Fraction-specific MR scans indicated an approximate 20% drop in SI after the first fraction, followed by a more gradual loss of SI, suggesting a persistence of tumor uptake after initial administration. We have demonstrated the ability to quantify nanoparticle uptake in patients with pancreatic cancer. Results indicate significant uptake of this new radiosensitizer agent in the pancreatic lesions as well as in the liver and kidneys. Follow-up scans and control subjects will inform tumor response due to nanoparticle-enhanced adaptive radiotherapy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. Parenchyma-Sparing Hepatic Cytoreduction for Neuroendocrine Tumours Metastases.
- Author
-
Hallet, J., Bennett, S., and Law, C.
- Subjects
- *
NEUROENDOCRINE tumors , *METASTASIS - Published
- 2022
- Full Text
- View/download PDF
24. Kinetics of water vapor diffusion in resins.
- Author
-
Krongauz, V., Bennett, S., and Ling, M.
- Subjects
- *
WATER vapor , *DIFFUSION , *GUMS & resins , *SORPTION , *DESORPTION kinetics , *METHYL methacrylate , *THERMOGRAVIMETRY - Abstract
The water vapor sorption and desorption kinetics were monitored in methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS), bromobutyl, ethylene-propylene-butadiene monomer (EPDM) rubber, and butyl rubber at various temperatures by gravimetric method. Modified thermogravimetric analysis system was built and used. The geometry of the samples was approximating that of the infinite two-sided plane sheet of certain thickness. The coefficients of water vapor diffusion in polymers were deduced by comparing the experimentally monitored kinetics and kinetics computed using diffusion coefficients as adjustable parameters. The activation energies of water vapor diffusion in these polymers were deduced in the temperature range from 30 to 75 °C. The activation energy of diffusion was 45.9 kJ mol in bromobutyl rubber, 46.4 kJ mol in butyl rubber, 60.3 kJ mol in EPDM rubber, and 43.5 kJ mol in MABS. Compensation effect was observed for water vapor diffusion in this series of polymers. Compensation effect parameters were determined to be, a = −23.9/ln(cm s) and b = 0.49/(mol kJ) × ln(cm s), in fair agreement with published data for water diffusion in polymers. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
25. New interpretation of the wings of the pterosaur Rhamphorhynchus muensteri based on the Zittel and Marsh specimens.
- Author
-
Bennett, S. Christopher
- Subjects
- *
PTEROSAURIA , *FOSSIL reptiles , *CALCITE , *FOREARM , *CARBONATE minerals , *EPIDERMIS - Abstract
The Zittel wing of Rhamphorhynchus muensteri is reinterpreted as preserving negative impressions of closely spaced broad flat actinofibrils that were replaced by calcite but were prepared away by the specimen's finder. The Marsh specimen preserves positive impressions of the dorsal and ventral surfaces of the wing, which show that the skin was smooth with fine wrinkles and that actinofibrils were not on the wing surface. Based on comparisons of those specimens, the dactylopatagium consisted of dorsal and ventral skins of epidermis and dermis surrounding a common hypodermis core, and keratinous actinofibrils developed in place within the dorsal epidermis adjacent to a layer of linear collagen fibers in the dorsal dermis. The actinofibrils and linear collagen fibers together formed the main functional structure of the dactylopatagium. That structure made the dactylopatagium somewhat stiff and essentially inextensible so that it folded up along discrete fold lines that probably were genetically determined. A pneumatic retrophalangeal wedge behind the antebrachium through at least wing phalanx 3 streamlined the transition between the thick wing spar and thin patagium. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. An external mandibular fenestra and other archosauriform characters in basal pterosaurs reexamined.
- Author
-
Bennett, S. Christopher
- Subjects
- *
PTEROSAURIA , *SCARS , *PERSONAL property , *MUSCLES , *ARGUMENT - Abstract
It was claimed that pterosaurs had external mandibular fenestrae, antorbital fossae and muscle scars homologous with the femoral fourth trochanter of archosauriforms, and that those characters suggested that the Pterosauria were within the clade Erythrosuchus + Archosauria. Pertinent parts of available specimens are described to confirm that one pterosaur had external mandibular fenestrae and one had antorbital fossae. However, arguments are presented that possession of external mandibular fenestrae does not support inclusion of the Pterosauria within the clade Erythrosuchus + Archosauria and that the antorbital fossae in the one pterosaur are not homologous with those of the clade Erythrosuchus + Archosauria. Arguments are also presented that the possession of a m. caudofemoralis scar by some pterosaurs does not support inclusion of the Pterosauria within the clade Erythrosuchus + Archosauria, whereas the lack of homologous antorbital fossae and a mound-like or aliform fourth trochanter supports exclusion of the Pterosauria from that clade. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. Performance of the Alere Determine™ HIV-1/2 Ag/Ab Combo Rapid Test with algorithm-defined acute HIV-1 infection specimens.
- Author
-
Parker, Monica M., Bennett, S. Berry, Sullivan, Timothy J., Fordan, Sally, Wesolowski, Laura G., Wroblewski, Kelly, and Gaynor, Anne M.
- Subjects
- *
DIAGNOSIS of HIV infections , *HIV virus enzymes , *IMMUNOASSAY , *IMMUNOGLOBULIN M , *IMMUNOGLOBULIN G - Abstract
Background The capacity of HIV Antigen/Antibody (Ag/Ab) immunoassays (IA) to detect HIV-1 p24 antigen has resulted in improved detection of HIV-1 infections in comparison to Ab-only screening assays. Since its introduction in the US, studies have shown that the Determine HIV-1/2 Ag/Ab Combo assay (Determine Ag/Ab) detects HIV infection earlier than laboratory-based IgM/IgG-sensitive IAs, but its sensitivity for HIV-1 p24 Ag detection is reduced compared to laboratory-based Ag/Ab assays. However, further evaluation is needed to assess its capacity to detect acute HIV-1 infection. Objective To assess the performance of Determine Ag/Ab in serum from acute HIV-1 infections. Study design Select serum specimens that screened reactive on a laboratory-based Ag/Ab IA or IgM/IgG Ab-only IA, with a negative or indeterminate supplemental antibody test and detectable HIV-1 RNA were retrospectively tested with Determine Ag/Ab. Results were compared with those of the primary screening immunoassay to evaluate concordance within this set of algorithm-defined acute infections. Results Of 159 algorithm-defined acute HIV-1 specimens, Determine Ag/Ab was reactive for 105 resulting in 66.0% concordance. Of 125 that were initially detected by a laboratory-based Ag/Ab IA, 81 (64.8%) were reactive by Determine Ag/Ab. A total of 34 acute specimens were initially detected by a laboratory-based IgM/IgG Ab-only IA and 24 (70.6%) of those were reactive by Determine Ag/Ab. Conclusions Due to their enhanced sensitivity, laboratory-based Ag/Ab IAs continue to be preferred over the Determine Ag/Ab as the screening method used by laboratories conducting HIV diagnostic testing on serum and plasma specimens. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
28. Non-homogeneous Behaviour of the Spatial Distribution of Macrospicules.
- Author
-
Gyenge, N., Bennett, S., and Erdélyi, R.
- Subjects
- *
LONGITUDE , *SPATIAL distribution (Quantum optics) , *ASTRONOMICAL observations , *HELIOSEISMOLOGY , *LONGITUDINAL method - Abstract
In this paper the longitudinal and latitudinal spatial distribution of macrospicules is examined. We found a statistical relationship between the active longitude (determined by sunspot groups) and the longitudinal distribution of macrospicules. This distribution of macrospicules shows an inhomogeneity and non-axisymmetrical behaviour in the time interval between June 2010 and December 2012, covered by observations of the Solar Dynamic Observatory (SDO) satellite. The enhanced positions of the activity and its time variation have been calculated. The migration of the longitudinal distribution of macrospicules shows a similar behaviour to that of the sunspot groups. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
29. Ankyrin is the major oxidised protein in erythrocyte membranes from end-stage renal disease patients on chronic haemodialysis and oxidation is decreased by dialysis and vitamin C supplementation.
- Author
-
Ruskovska, T., Bennett, S. J, Brown, C. R., Dimitrov, S., Kamcev, N., and Griffiths, H. R.
- Subjects
- *
ANKYRINS , *ERYTHROCYTE membranes , *ADAPTOR proteins , *KIDNEY diseases , *CARBONYL compounds , *ENZYME-linked immunosorbent assay - Abstract
Chronically haemodialysed end-stage renal disease patients are at high risk of morbidity arising from complications of dialysis, the underlying pathology that has led to renal disease and the complex pathology of chronic kidney disease. Anaemia is commonplace and its origins are multifactorial, involving reduced renal erythropoietin production, accumulation of uremic toxins and an increase in erythrocyte fragility. Oxidative damage is a common risk factor in renal disease and its co-morbidities and is known to cause erythrocyte fragility. Therefore, we have investigated the hypothesis that specific erythrocyte membrane proteins are more oxidised in end-stage renal disease patients and that vitamin C supplementation can ameliorate membrane protein oxidation. Eleven patients and 15 control subjects were recruited to the study. Patients were supplemented with 2 × 500 mg vitamin C per day for 4 weeks. Erythrocyte membrane proteins were prepared pre- and post-vitamin C supplementation for determination of protein oxidation. Total protein carbonyls were reduced by vitamin C supplementation but not by dialysis when investigated by enzyme linked immunosorbent assay. Using a western blot to detect oxidised proteins, one protein band, later identified as containing ankyrin, was found to be oxidised in patients but not controls and was reduced significantly by 60% in all patients after dialysis and by 20% after vitamin C treatment pre-dialysis. Ankyrin oxidation analysis may be useful in a stratified medicines approach as a possible marker to identify requirements for intervention in dialysis patients. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
30. Bilayer fractional quantum Hall states with dipoles.
- Author
-
Yao, N. Y., Bennett, S. D., Laumann, C. R., Lev, B. L., and Gorshkov, A. V.
- Subjects
- *
QUANTUM Hall effect , *DYSPROSIUM , *MAGNETIC dipoles , *DIPOLE-dipole interactions , *INTERACTING boson models - Abstract
Using the example of dysprosium atoms in an optical lattice, we show how dipolar interactions between magnetic dipoles can be used to obtain fractional quantum Hall states. In our approach, dysprosium atoms are trapped one atom per site in a deep optical lattice with negligible tunneling. Microwave and spatially dependent optical dressing fields are used to define an effective spin-12 or spin-1/2 degree of freedom in each atom. Thinking of spin-12 particles as hard-core bosons, dipole-dipole interactions give rise to boson hopping, topological flat bands with Chern number 1, and the υ=½ Laughlin state. Thinking of spin-1/2 particles as two-component hard-core bosons, dipole-dipole interactions again give rise to boson hopping, topological flat bands with Chern number 2, and the bilayer Halperin (2,2,1) state. By adjusting the optical fields, we find a phase diagram, in which the (2,2,1) state competes with superfluidity. Generalizations to solid-state magnetic dipoles are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
31. Epidemiology and Ecology of H3N8 Canine Influenza Viruses in US Shelter Dogs.
- Author
-
Pecoraro, H.L., Bennett, S., Huyvaert, K.P., Spindel, M.E., and Landolt, G.A.
- Subjects
- *
INFLUENZA viruses , *VETERINARY epidemiology , *VETERINARIANS , *VIRUS diseases in dogs , *LOGISTIC regression analysis , *INFORMATION theory - Abstract
Background H3N8 canine influenza virus ( CIV) infection might contribute to increased duration of shelter stay for dogs. Greater understanding of factors contributing to CIV within shelters could help veterinarians identify control measures for CIV. Objectives To assess community to shelter dog CIV transmission, estimate true prevalence of CIV, and determine risk factors associated with CIV in humane shelters. Animals 5,160 dogs upon intake or discharge from 6 US humane shelters, December 2009 through January 2012. Methods A cross-sectional study was performed with prospective convenience sampling of 40 dogs from each shelter monthly. Nasal swabs and serum samples were collected. Hemagglutination inhibition and real-time reverse transcriptase-polymerase chain reaction assays were performed for each nasal and serum sample. True prevalence was estimated by stochastic latent class analysis. Logistic regression was used to identify risk factors associated with CIV shedding and seropositivity. Results Nasal swabs were positive from 4.4% of New York ( NY), 4.7% of Colorado ( CO), 3.2% of South Carolina, 1.2% of Florida, and 0% of California and Texas shelter dogs sampled. Seropositivity was the highest in the CO shelter dogs at 10%, and NY at 8.5%. Other shelters had 0% seropositivity. Information-theoretic analyses suggested that CIV shedding was associated with region, month, and year (model weight = 0.95) and comingling/cohousing (model weight = 0.92). Conclusions and Clinical Importance Community dogs are a likely source of CIV introduction into humane shelters and once CIV has become established, dog-to-dog transmission maintains the virus within a shelter. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Carbon adsorption onto Fe oxyhydroxide stalks produced by a lithotrophic iron-oxidizing bacteria.
- Author
-
Bennett, S. A., Toner, B. M., Barco, R., and Edwards, K. J.
- Subjects
- *
CARBON , *HYDROXIDES , *IRON oxidation , *POLYSACCHARIDES , *NANOPARTICLES analysis - Abstract
Iron ( Fe)-oxidizing bacteria have the potential to produce morphologically unique structures that may be used as biosignatures in geological deposits. One particular example is Mariprofundus ferrooxydans, which produces extracellular twisted ribbon-like stalks consisting of ferrihydrite, co-located with organic and inorganic elements. It is currently thought that M. ferrooxydans excrete and co-precipitate polysaccharides and Fe simultaneously; however, the cellular production of these polysaccharides has yet to be confirmed. Here, we report on a time-series study that used scanning transmission X-ray microscopy and C 1s and Ca 2p near-edge X-ray adsorption fine structure spectroscopy to investigate production of polysaccharides over the growth cycle of M. ferrooxydans. The production and morphology of twisted iron stalks were consistent with previous observations, but unexpectedly, in the log phase, the carbon content of the stalks was extremely low. It was not until stationary growth phase that a significant component of carbon was detected on the stalks. During the log phase, low levels of carbon, only detectable when the stalks were thin, suggested that M. ferrooxydans produce an extracellular polysaccharide template onto which the Fe precipitates. By stationary phase, the increased carbon association with the stalks was a result of adsorption of organic compounds that were released during osmotic shock post-stalk production. In the environment, elevated concentrations of DOC could adsorb onto the Fe stalks as well as a number of other elements, for example, Si, P, Ca, which, by preventing chemical interactions between the Fe nanoparticles, will prevent structural deformation during recrystallization and preserve the structure of these filaments in the rock record. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
33. The accuracy of Internet search engines to predict diagnoses from symptoms can be assessed with a validated scoring system.
- Author
-
Shenker, Bennett S.
- Subjects
- *
WEB search engines , *DIAGNOSTIC imaging , *INTERNET research , *PREDICTION theory - Abstract
Highlights: [•] The DAISE score quantifies the ability of Internet search engines to predict diagnoses. [•] The DAISE score is a valid and reliable instrument. [•] The DAISE score can be used in future Internet research. [•] Google, Bing, and Ask performed equally well predicting diagnoses. [•] Internet search engines produce correct differential diagnoses in the majority of cases. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
34. The antioxidant enzyme peroxiredoxin-2 is depleted in lymphocytes seven days after ultra-endurance exercise.
- Author
-
Turner, J. E., Bennett, S. J., Campbell, J. P., Bosch, J. A., Aldred, S., and Griffiths, H. R.
- Abstract
Purpose. Peroxiredoxin-2 (PRDX-2) is an antioxidant and chaperone-like protein critical for cell function. This study examined whether the levels of lymphocyte PRDX-2 are altered over 1 month following ultra-endurance exercise. Methods. Nine middle-aged men undertook a single-stage, multi-day 233 km (145 mile) ultra-endurance running race. Blood was collected immediately before (Pre), upon completion/retirement (Post), and following the race at Day 1, Day 7 and Day 28. Lymphocyte lysates were examined for PRDX-2 by reducing and non-reducing SDS-PAGE with western blotting. In a sub-group of men who completed the race (n = 4), PRDX-2 oligomeric state (indicative of redox status) was investigated. Results. Ultra-endurance exercise caused significant changes in lymphocyte PRDX-2 (F(4,32) 3.409, p = 0.020, η2 = 0.299): 7 days after the race, PRDX-2 levels in lymphocytes had fallen to 30% of pre-race values (p = 0.013) and returned to near-normal levels at Day 28. Non-reducing gels demonstrated that dimeric PRDX-2 (intracellular reduced PRDX-2 monomers) was increased in three of four race completers immediately post-race, indicative of an ‘antioxidant response’. Moreover, monomeric PRDX-2 was also increased immediately post-race in two of four race-completing subjects, indicative of oxidative damage, which was not detectable by Day 7. Conclusions. Lymphocyte PRDX-2 was decreased below normal levels 7 days after ultra-endurance exercise. Excessive accumulation of reactive oxygen species induced by ultra-endurance exercise may underlie depletion of lymphocyte PRDX-2 by triggering its turnover after oxidation. Low levels of lymphocyte PRDX-2 could influence cell function and might, in part, explain reports of dysregulated immunity following ultra-endurance exercise. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
35. Phonon cooling and lasing with nitrogen-vacancy centers in diamond.
- Author
-
Kepesidis, K. V., Bennett, S. D., Portolan, S., Lukin, M. D., and Rabl, P.
- Subjects
- *
STRAINS & stresses (Mechanics) , *DIAMONDS , *RESONATORS , *PHONONS , *NITROGEN , *LASERS , *COOLING - Abstract
We investigate the strain-induced coupling between a nitrogen-vacancy impurity and a resonant vibrational mode of a diamond nanoresonator. We show that under near-resonant laser excitation of the electronic states of the impurity, this coupling can modify the state of the resonator and either cool the resonator close to the vibrational ground state or drive it into a large-amplitude coherent state. We derive a semiclassical model to describe both effects and evaluate the stationary state of the resonator mode under various driving conditions. In particular, we find that by exploiting resonant single- and multiphonon transitions between near-degenerate electronic states, the coupling to high-frequency vibrational modes can be significantly enhanced and dominate over the intrinsic mechanical dissipation. Our results show that a single nitrogen-vacancy impurity can provide a versatile tool to manipulate and probe individual phonon modes in nanoscale diamond structures. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
36. Long-Term Dependency Outcomes In Older Adults Following Hepatectomy And Pancreatectomy For Cancer: A Population-Based Analysis.
- Author
-
Bennett, S., Chesney, T.R., Coburn, N.G., Haas, B., Zuk, V., Mahar, A.L., Hsu, A.T., Zhao, H., Menjak, I., Manuel, D., Gandell, D., Wright, F.C., and Hallet, J.
- Subjects
- *
PANCREATECTOMY , *OLDER people , *HEPATECTOMY , *MENTAL health services , *ACUTE care nurse practitioners , *NURSING care facilities - Abstract
We evaluated healthcare dependency by examining homecare use and institution-free survival (IFS) following hepatectomy and pancreatectomy for cancer in OA. Trends in outcomes were similar for hepatectomy and pancreatectomy patients, but with higher healthcare dependence following pancreatectomy. [Extracted from the article]
- Published
- 2020
- Full Text
- View/download PDF
37. Phonon-Induced Spin-Spin Interactions in Diamond Nanostructures: Application to Spin Squeezing.
- Author
-
Bennett, S. D., Yao, N. Y., Otterbach, J., Zoller, P., Rabl, P., and Lukin, M. D.
- Subjects
- *
SPIN-spin interactions , *PHONONS , *DIAMONDS , *NANOSTRUCTURES , *QUANTUM information science - Abstract
We propose and analyze a novel mechanism for long-range spin-spin interactions in diamond nanostructures. The interactions between electronic spins, associated with nitrogen-vacancy centers in diamond, are mediated by their coupling via strain to the vibrational mode of a diamond mechanical nanoresonator. This coupling results in phonon-mediated effective spin-spin interactions that can be used to generate squeezed states of a spin ensemble. We show that spin dephasing and relaxation can be largely suppressed, allowing for substantial spin squeezing under realistic experimental conditions. Our approach has implications for spin-ensemble magnetometry, as well as phonon-mediated quantum information processing with spin qubits. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
38. Measuring mechanical motion with a single spin.
- Author
-
Bennett, S. D., Kolkowitz, S., Unterreithmeier, Q. P., Rabl, P., Jayich, A. C. Bleszynski, Harris, J. G. E., and Lukin, M. D.
- Subjects
- *
MECHANICAL oscillations , *DETECTORS , *NITROGEN , *CANTILEVERS , *HEATING - Abstract
We study theoretically the measurement of a mechanical oscillator using a single two-level system as a detector. In a recent experiment, we used a single electronic spin associated with a nitrogen--vacancy center in diamond to probe the thermal motion of a magnetized cantilever at room temperature (Kolkowitz et al 2012 Science 335 1603). Here, we present a detailed analysis of the sensitivity limits of this technique, as well as the possibility to measure the zero-point motion of the oscillator. Further, we discuss the issue of measurement backaction in sequential measurements and find that although backaction heating can occur, it does not prohibit the detection of zero-point motion. Throughout the paper, we focus on the experimental implementation of a nitrogen--vacancy center coupled to a magnetic cantilever; however, our results are applicable to a wide class of spin--oscillator systems. The implications for the preparation of nonclassical states of a mechanical oscillator are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
39. Mechanically probing coherent tunneling in a double quantum dot.
- Author
-
Gardner, J., Bennett, S. D., and Clerk, A. A.
- Subjects
- *
QUANTUM dots , *QUANTUM electronics , *ATOMIC force microscopy , *CANTILEVERS , *EIGENVALUES - Abstract
We study theoretically the interaction between the charge dynamics of a few-electron double quantum dot and a capacitively coupled atomic force microscopy cantilever, a setup realized in several recent experiments. We demonstrate that the dot-induced frequency shift and damping of the cantilever can be used as a sensitive probe of coherent interdot tunneling, and that these effects can be used to quantitatively extract both the magnitude of the coherent interdot tunneling and (in some cases) the value of the double-dot T1 time. We also show how the adiabatic modulation of the dot eigenstates by the cantilever motion leads to substantial effects which are completely absent in the more studied single-dot case. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
40. Antigen-specific T cell responses to BK polyomavirus antigens identify functional anti-viral immunity and may help to guide immunosuppression following renal transplantation.
- Author
-
Chakera, A., Bennett, S., Lawrence, S., Morteau, O., Mason, P. D., O'Callaghan, C. A., and Cornall, R. J.
- Subjects
- *
POLYOMAVIRUS diseases , *T cells , *ANTIVIRAL agents , *ENZYME-linked immunosorbent assay , *KIDNEY transplantation , *EPSTEIN-Barr virus , *VIRAL replication , *ANTIGENS - Abstract
Summary Infection with the polyoma virus BK (BKV) is a major cause of morbidity following renal transplantation. Limited understanding of the anti-viral immune response has prevented the design of a strategy that balances treatment with the preservation of graft function. The proven utility of interferon-gamma enzyme-linked immunospot (ELISPOT) assays to measure T cell responses in immunocompetent hosts was the basis for trying to develop a rational approach to the management of BKV following renal transplantation. In a sample of transplant recipients and healthy controls, comparisons were made between T cell responses to the complete panel of BKV antigens, the Epstein-Barr virus (EBV) antigens, BZLF1 and EBNA1, and the mitogen phytohaemagglutinin (PHA). Correlations between responses to individual antigens and immunosuppressive regimens were also analysed. Antigen-specific T cell responses were a specific indicator of recent or ongoing recovery from BKV infection ( P < 0·05), with responses to different BKV antigens being highly heterogeneous. Significant BKV immunity was undetectable in transplant patients with persistent viral replication or no history of BKV reactivation. Responses to EBV antigens and mitogen were reduced in patients with BKV reactivation, but these differences were not statistically significant. The T cell response to BKV antigens is a useful and specific guide to recovery from BKV reactivation in renal transplant recipients, provided that the full range of antigenic responses is measured. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
41. Discrepancy between inner and overt speech: Implications for post-stroke aphasia and normal language processing.
- Author
-
Geva S, Bennett S, Warburton EA, and Patterson K
- Subjects
- *
DIAGNOSIS of aphasia , *ANALYSIS of variance , *APHASIA , *CEREBROVASCULAR disease , *CHI-squared test , *SPEECH evaluation , *U-statistics , *PHONOLOGICAL awareness , *ETIOLOGY of diseases , *DISEASE complications - Abstract
Background: Patients with aphasia often complain that there is a poor correlation between the words they think (inner speech) and the words they say (overt speech). Aims: This study tried to characterise the relation between inner speech and overt speech in post-stroke aphasia. Methods & Procedures: We tested language abilities, speech apraxia, and performance on inner speech tasks, including homophone and rhyme judgements, of 27 patients with chronic post-stroke aphasia. Outcomes & Results: The patients with aphasia were distributed across the entire spectrum of abilities related to both inner and overt speech. For most patients, performance levels of inner and overt speech were similar. However, some patients had relatively better-preserved inner speech with a marked deficit in overt speech, while in others the opposite pattern was observed. Conclusions: The results are discussed within the framework of current models of language, and their implications for language therapy and aphasia diagnosis are outlined. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
42. Beyond the 'digital natives' debate: Towards a more nuanced understanding of students' technology experiences.
- Author
-
Bennett, S. and Maton, K.
- Subjects
- *
TECHNOLOGICAL innovations , *EDUCATIONAL technology , *COMPUTER assisted instruction , *EDUCATORS , *INTERNET in education - Abstract
The idea of the 'digital natives', a generation of tech-savvy young people immersed in digital technologies for which current education systems cannot cater, has gained widespread popularity on the basis of claims rather than evidence. Recent research has shown flaws in the argument that there is an identifiable generation or even a single type of highly adept technology user. For educators, the diversity revealed by these studies provides valuable insights into students' experiences of technology inside and outside formal education. While this body of work provides a preliminary understanding, it also highlights subtleties and complexities that require further investigation. It suggests, for example, that we must go beyond simple dichotomies evident in the digital natives debate to develop a more sophisticated understanding of our students' experiences of technology. Using a review of recent research findings as a starting point, this paper identifies some key issues for educational researchers, offers new ways of conceptualizing key ideas using theoretical constructs from Castells, Bourdieu and Bernstein, and makes a case for how we need to develop the debate in order to advance our understanding. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
43. Dislocations and their reduction in GaN.
- Author
-
Bennett, S. E.
- Subjects
- *
GALLIUM nitride , *LIGHT emitting diodes , *ELECTROMAGNETIC waves , *SPECTRUM analysis , *LIGHT sources - Abstract
Gallium nitride (GaN) is a semiconductor used to make light emitting diodes, a technology that could decrease global energy demands significantly if used worldwide. Yet there are barriers to making high efficiency GaN based devices: defects, including threading dislocations (TDs), hamper the quality of the GaN crystalline film. The hypotheses proposed to explain the origin of TDs are critically reviewed. It has been suggested that TDs form upon GaN island coalescence during initial stages of crystalline film growth, yet some transmission electron microscopy and atomic force microscopy studies have shown few TDs at coalescence boundaries. Although harmful, TDs have a lesser effect on nitride based devices than on other compound semiconductors. Thus, GaN based devices are able to produce light despite high dislocation densities. This phenomenon has led to debate over the role of TDs in charge carrier recombination, which is reviewed. Some suggest that charge carriers arrive at TDs and recombine in a non-radiative manner, whereas others claim that they are repelled from the dislocations because the dislocation cores are electrically charged. The reduction of TDs in GaN films furthers the drive towards high efficiency devices. The final sections of this review address ways to effect reductions in TD density. Methods include changing growth conditions (including temperature and pressure), dosing the substrate with silane, and the exploitation of interlayers deposited during growth. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
44. Imaging dislocations in gallium nitride across broad areas using atomic force microscopy.
- Author
-
Bennett, S. E., Holec, D., Kappers, M. J., Humphreys, C. J., and Oliver, R. A.
- Subjects
- *
ATOMIC force microscopy , *SCANNING probe microscopy , *EPITAXY , *OPTOELECTRONIC devices , *TRANSMISSION electron microscopy , *DISLOCATIONS in metals , *SILANE , *EQUIPMENT & supplies - Abstract
We have employed an atomic force microscope with a high sampling rate to image GaN samples grown using an epitaxial layer overgrowth technique and treated with silane and ammonia to enlarge the surface pits associated with threading dislocations (TDs). This allows TDs to be identified in high pixel density images tens of microns in size providing detailed information about the spatial distribution of the TDs. An automated software tool has been developed, which identifies the coordinates of the TDs in the image. Additionally, we have imaged the same sample using Kelvin probe force microscopy, again at high pixel density, providing data about the local changes in surface potential associated with hundreds of dislocations. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
45. Stanford V program for locally extensive and advanced Hodgkin lymphoma: the Memorial Sloan-Kettering Cancer Center experience.
- Author
-
Edwards-Bennett, S. M., Jacks, L. M., Moskowitz, C. H., Wu, E. J., Zhang, Z., Noy, A., Portlock, C. S., Straus, D. J., Zelenetz, A. D., and Yahalom, J.
- Subjects
- *
HODGKIN'S disease , *LYMPHOMAS , *CANCER treatment , *MEDICAL centers - Abstract
Background: The Stanford group has reported excellent results with the Stanford V regimen for patients with bulky and/or advanced Hodgkin lymphoma (HL). However, Gobbi reported markedly inferior failure-free survival (FFS) comparing Stanford V to other regimens but included major deviations from the original program. We retrospectively examined whether treatment at our institution carefully following Stanford V guidelines would confirm the original Stanford outcome data. [ABSTRACT FROM PUBLISHER]
- Published
- 2010
- Full Text
- View/download PDF
46. An Experimental Study of Opinion on Climate Change: Labile Causalities and Stable Realities.
- Author
-
Bennett, S. E.
- Subjects
- *
CLIMATE change , *PUBLIC opinion , *VIDEOS , *POLITICAL participation , *ENVIRONMENTAL policy , *GREENHOUSE gases , *GLOBAL warming - Abstract
This article presents an experimental study of public opinions on climate change. The study examines the effectiveness of a video information treatment in changing opinions on issues concerning climate change. It assesses the impact of opinions in conjunction with various forms of political participation on the direction of policy about climate change. In addition, the study discusses the variables that greenhouse gas emission is the primary cause of climate change and that climate change involves more than just global warming.
- Published
- 2010
- Full Text
- View/download PDF
47. An Experimental Study of Opinion on Climate Change: Labile Causalities and Stable Realities.
- Author
-
Bennett, S. E.
- Subjects
- *
PSYCHOLOGICAL research , *EFFECT of human beings on climate change , *PUBLIC opinion , *GLOBAL warming , *CLIMATE change , *RELIGION - Abstract
The article presents the results of research on people's opinions about global warming and climate change, and how easily those opinions can be influenced. Some issues addressed by related previous studies are noted. Details of the research protocol, which involved 45 people, a questionnaire, and a video titled "The Great Global Warming Swindle," are provided. It was found that the video tended to significantly affect people's opinions on the question of whether global warming is caused by humans. It had less effect on beliefs about the existence of climate change.
- Published
- 2010
- Full Text
- View/download PDF
48. An Experimental Study of Opinion on Climate Change: Labile Causalities and Stable Realities.
- Author
-
Bennett, S. E.
- Subjects
- *
CLIMATE change , *BELIEF change , *PUBLIC opinion , *GLOBAL warming , *HUMAN ecology , *ENVIRONMENTALISM , *RIGHT & left (Political science) , *THEORY of knowledge , *CAUSATION (Philosophy) , *CHANGE (Psychology) - Abstract
The article presents a study on changing public opinion with a video in the context of opinion on climate change and global warming. The article discusses conventional views on the causation of climate change, including the view that global warming is a serious issue and was caused by human factors. The growth of the environmental movement is considered, along with the left-right politics of environmentalism. The study found that informational treatments can change perceptions of causal mechanisms.
- Published
- 2010
- Full Text
- View/download PDF
49. An Experimental Study of Opinion on Climate Change: Labile Causalities and Stable Realities.
- Author
-
Bennett, S. E.
- Published
- 2010
- Full Text
- View/download PDF
50. Islands of speciation or mirages in the desert? Examining the role of restricted recombination in maintaining species.
- Author
-
Noor, M. A. F. and Bennett, S. M.
- Subjects
- *
MIRAGES , *SPECIES , *GENOMES , *BIOLOGICAL divergence , *CENTROMERE - Abstract
Over the past decade, many studies documented high genetic divergence between closely related species in genomic regions experiencing restricted recombination in hybrids, such as within chromosomal rearrangements or areas adjacent to centromeres. Such regions have been called ‘islands of speciation’ because of their presumed role in maintaining the integrity of species despite gene flow elsewhere in the genome. Here, we review alternative explanations for such patterns. Segregation of ancestral variation or artifacts of nucleotide diversity within species can readily lead to higher FST in regions of restricted recombination than other parts of the genome, even in the complete absence of interspecies gene flow, and thereby cause investigators to erroneously conclude that islands of speciation exist. We conclude by discussing strengths and weaknesses of various means for testing the role of restricted recombination in maintaining species. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.