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CMOS Compatible Hydrogen Sensor Using Platinum Gate and ALD-Aluminum Oxide. SENSORS (BASEL, SWITZERLAND) 2024; 24:3020. [PMID: 38793874 DOI: 10.3390/s24103020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/01/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024]
Abstract
In this study, a p-Si/ALD-Al2O3/Ti/Pt MOS (metal oxide semiconductor) device has been fabricated and used as a hydrogen sensor. The use of such a stack enables a reliable, industry-compatible CMOS fabrication process. ALD-Al2O3 has been chosen as it can be integrated into the back end of the line (BEOL) or in CMOS, post processing. The device response and recovery are demonstrated with good correlation between the capacitance variation and the hydrogen concentration. Detection down to 20 ppm at 140 °C was obtained and a response time of 56 s for 500 ppm was recorded.
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Immunologic aspects of preeclampsia. AJOG GLOBAL REPORTS 2024; 4:100321. [PMID: 38586611 PMCID: PMC10994979 DOI: 10.1016/j.xagr.2024.100321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024] Open
Abstract
Preeclampsia is a syndrome with multiple etiologies. The diagnosis can be made without proteinuria in the presence of dysfunction of at least 1 organ associated with hypertension. The common pathophysiological pathway includes endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. There is evidence to support, among others, immunologic causes of preeclampsia. Unlike defense immunology, reproductive immunology is not based on immunologic recognition systems of self/non-self and missing-self but on immunotolerance and maternal-fetal cellular interactions. The main mechanisms of immune escape from fetal to maternal immunity at the maternal-fetal interface are a reduction in the expression of major histocompatibility complex molecules by trophoblast cells, the presence of complement regulators, increased production of indoleamine 2,3-dioxygenase, activation of regulatory T cells, and an increase in immune checkpoints. These immune protections are more similar to the immune responses observed in tumor biology than in allograft biology. The role of immune and nonimmune decidual cells is critical for the regulation of trophoblast invasion and vascular remodeling of the uterine spiral arteries. Regulatory T cells have been found to play an important role in suppressing the effectiveness of other T cells and contributing to local immunotolerance. Decidual natural killer cells have a cytokine profile that is favored by the presence of HLA-G and HLA-E and contributes to vascular remodeling. Studies on the evolution of mammals show that HLA-E, HLA-G, and HLA-C1/C2, which are expressed by trophoblasts and their cognate receptors on decidual natural killer cells, are necessary for the development of a hemochorial placenta with vascular remodeling. The activation or inhibition of decidual natural killer cells depends on the different possible combinations between killer cell immunoglobulin-like receptors, expressed by uterine natural killer cells, and the HLA-C1/C2 antigens, expressed by trophoblasts. Polarization of decidual macrophages in phenotype 2 and decidualization of stromal cells are also essential for high-quality vascular remodeling. Knowledge of the various immunologic mechanisms required for adequate vascular remodeling and their dysfunction in case of preeclampsia opens new avenues of research to identify novel biological markers or therapeutic targets to predict or prevent the onset of preeclampsia.
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Time Required for Gross Examination of Routine Second and Third Trimester Singleton Placentas by Pathologists' Assistants. Pediatr Dev Pathol 2023; 26:466-471. [PMID: 37672728 PMCID: PMC10685689 DOI: 10.1177/10935266231196015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
INTRODUCTION In both Canada and the United States, workload measurement for anatomic pathology is mainly based on complexity and clinical significance of specimens, with gross examination being a considerable contributor. While Pathologists' Assistants (PAs) play an increasing role in gross examination, there is little known regarding the time required for PAs to complete grossing tasks. This information is essential for effective staffing and workload management in pathology laboratories. The objective of our study was to determine the time required for PAs to gross second and third trimester singleton placentas in a large tertiary hospital with a significant perinatal pathology service. MATERIALS AND METHODS For our study, 7 certified PAs each grossed a minimum of 10 second and third trimester singleton placentas using a standard placental grossing protocol, an electronic laboratory information system, and voice recognition dictation software. Placental specimens requiring photography, sampling for ancillary studies, or immediate pathologist's consultation were excluded. We calculated average and standard deviation of grossing times for each PA, overall average grossing time, and 95% confidence interval using a mixed linear regression model. We analyzed the impact of PA job experience, degree obtained, and number of blocks prepared on overall average in a multivariate analysis. RESULTS The mean grossing times for each PA ranged from 11.0 (standard deviation [sd] = 2.0) to 17.8 (sd = 4.5) minutes. The overall average grossing time was 14.5 minutes, with a 95% confidence interval of 11.7 to 17.3 minutes. In multivariate analysis, an increase in the number of blocks prepared was significantly associated with longer overall average grossing time. If 4 blocks were prepared consistently, the model predicted a slightly lower overall average of 13.3 minutes, with a 95% confidence interval of 10.9 to 15.7 minutes. DISCUSSION To our knowledge, our study is the first to objectively report time required for PAs to perform gross examinations of routine second and third trimester singleton placentas. The methodology of our study is replicable and can be applied to other specimen types and laboratory settings. Previously, estimated grossing times for specimens were primarily based on retrospective surveys, which were susceptible to recall errors and subjectivity. However, our study demonstrates objective data collection is achievable. Furthermore, the data collected from this study offer valuable insights into the accuracy of previous and current pathology workload models for second and third trimester singleton placentas.
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Colonic innate immune defenses and microbiota alterations in acute swine dysentery. Microb Pathog 2022; 173:105873. [DOI: 10.1016/j.micpath.2022.105873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022]
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Voltage-dependent synaptic plasticity: Unsupervised probabilistic Hebbian plasticity rule based on neurons membrane potential. Front Neurosci 2022; 16:983950. [PMID: 36340782 PMCID: PMC9634260 DOI: 10.3389/fnins.2022.983950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/05/2022] [Indexed: 11/27/2022] Open
Abstract
This study proposes voltage-dependent-synaptic plasticity (VDSP), a novel brain-inspired unsupervised local learning rule for the online implementation of Hebb’s plasticity mechanism on neuromorphic hardware. The proposed VDSP learning rule updates the synaptic conductance on the spike of the postsynaptic neuron only, which reduces by a factor of two the number of updates with respect to standard spike timing dependent plasticity (STDP). This update is dependent on the membrane potential of the presynaptic neuron, which is readily available as part of neuron implementation and hence does not require additional memory for storage. Moreover, the update is also regularized on synaptic weight and prevents explosion or vanishing of weights on repeated stimulation. Rigorous mathematical analysis is performed to draw an equivalence between VDSP and STDP. To validate the system-level performance of VDSP, we train a single-layer spiking neural network (SNN) for the recognition of handwritten digits. We report 85.01 ± 0.76% (Mean ± SD) accuracy for a network of 100 output neurons on the MNIST dataset. The performance improves when scaling the network size (89.93 ± 0.41% for 400 output neurons, 90.56 ± 0.27 for 500 neurons), which validates the applicability of the proposed learning rule for spatial pattern recognition tasks. Future work will consider more complicated tasks. Interestingly, the learning rule better adapts than STDP to the frequency of input signal and does not require hand-tuning of hyperparameters.
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Exploiting Non-idealities of Resistive Switching Memories for Efficient Machine Learning. FRONTIERS IN ELECTRONICS 2022. [DOI: 10.3389/felec.2022.825077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Novel computing architectures based on resistive switching memories (also known as memristors or RRAMs) have been shown to be promising approaches for tackling the energy inefficiency of deep learning and spiking neural networks. However, resistive switch technology is immature and suffers from numerous imperfections, which are often considered limitations on implementations of artificial neural networks. Nevertheless, a reasonable amount of variability can be harnessed to implement efficient probabilistic or approximate computing. This approach turns out to improve robustness, decrease overfitting and reduce energy consumption for specific applications, such as Bayesian and spiking neural networks. Thus, certain non-idealities could become opportunities if we adapt machine learning methods to the intrinsic characteristics of resistive switching memories. In this short review, we introduce some key considerations for circuit design and the most common non-idealities. We illustrate the possible benefits of stochasticity and compression with examples of well-established software methods. We then present an overview of recent neural network implementations that exploit the imperfections of resistive switching memory, and discuss the potential and limitations of these approaches.
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Miniaturizing neural networks for charge state autotuning in quantum dots. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1088/2632-2153/ac34db] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
A key challenge in scaling quantum computers is the calibration and control of multiple qubits. In solid-state quantum dots (QDs), the gate voltages required to stabilize quantized charges are unique for each individual qubit, resulting in a high-dimensional control parameter space that must be tuned automatically. Machine learning techniques are capable of processing high-dimensional data—provided that an appropriate training set is available—and have been successfully used for autotuning in the past. In this paper, we develop extremely small feed-forward neural networks that can be used to detect charge-state transitions in QD stability diagrams. We demonstrate that these neural networks can be trained on synthetic data produced by computer simulations, and robustly transferred to the task of tuning an experimental device into a desired charge state. The neural networks required for this task are sufficiently small as to enable an implementation in existing memristor crossbar arrays in the near future. This opens up the possibility of miniaturizing powerful control elements on low-power hardware, a significant step towards on-chip autotuning in future QD computers.
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Oxygen vacancy engineering of TaO x-based resistive memories by Zr doping for improved variability and synaptic behavior. NANOTECHNOLOGY 2021; 32:405202. [PMID: 34167106 DOI: 10.1088/1361-6528/ac0e67] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Resistive switching (RS) devices are promising forms of non-volatile memory. However, one of the biggest challenges for RS memory applications is the device-to-device (D2D) variability, which is related to the intrinsic stochastic formation and configuration of oxygen vacancy (VO) conductive filaments (CFs). In order to reduce the D2D variability, control over the formation and configuration of oxygen vacancies is paramount. In this study, we report on the Zr doping of TaOx-based RS devices prepared by pulsed-laser deposition as an efficient means of reducing the VOformation energy and increasing the confinement of CFs, thus reducing D2D variability. Our findings were supported by XPS, spectroscopic ellipsometry and electronic transport analysis. Zr-doped films showed increased VOconcentration and more localized VOs, due to the interaction with Zr. DC and pulse mode electrical characterization showed that the D2D variability was decreased by a factor of seven, the resistance window was doubled, and a more gradual and monotonic long-term potentiation/depression in pulse switching was achieved in forming-free Zr:TaOxdevices, thus displaying promising performance for artificial synapse applications.
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Conductive filament evolution dynamics revealed by cryogenic (1.5 K) multilevel switching of CMOS-compatible Al 2O 3/TiO 2 resistive memories. NANOTECHNOLOGY 2020; 31:445205. [PMID: 32674084 DOI: 10.1088/1361-6528/aba6b4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Non-volatile resistive switching devices are considered as prime candidates for next-generation memory applications operating at room temperature and above, such as resistive random-access memories or brain-inspired in-memory computing. However, their operability in cryogenic conditions remains to be mastered to adopt these devices as building blocks enabling large-scale quantum technologies via quantum-classical electronics co-integration. This study demonstrates multilevel switching at 1.5 K of Al2O3/TiO2-x resistive memory devices fabricated with complementary metal-oxide-semiconducto-compatible processes and materials. The I-V characteristics exhibit a negative differential resistance (NDR) effect due to a Joule-heating-induced metal-insulator transition of the Ti4O7 conductive filament. Carrier transport analysis of all multilevel switching I-V curves show that while the insulating regime follows the space charge limited current (SCLC) model for all resistance states, the conduction in the metallic regime is dominated by SCLC and trap-assisted tunneling for low- and high-resistance states respectively. A non-monotonic conductance evolution is observed in the insulating regime, as opposed to the continuous and gradual conductance increase and decrease obtained in the metallic regime during the multilevel SET and RESET operations. Cryogenic transport analysis coupled to an analytical model accounting for the metal-insulator-transition-induced NDR effects and the resistance states of the device provide new insights on the conductive filament evolution dynamics and resistive switching mechanisms. Our findings suggest that the non-monotonic conductance evolution in the insulating regime is due to the combined effects of longitudinal and radial variations of the Ti4O7 conductive filament during the switching. This behavior results from the interplay between temperature- and field-dependent geometrical and physical characteristics of the filament.
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Erratum: Conductive filament evolution dynamics revealed by cryogenic (1.5 K) multilevel switching of CMOS-compatible Al 2O 3/TiO 2resistive memories (2020 Nanotechnology31 445205). NANOTECHNOLOGY 2020; 31:499601. [PMID: 35166695 DOI: 10.1088/1361-6528/abb301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 06/14/2023]
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Decision-making based on sFlt-1/PlGF ratios: are immunoassay results interchangeable for diagnosis or prognosis of preeclampsia? Clin Chem Lab Med 2020; 59:e87-e89. [PMID: 32238604 DOI: 10.1515/cclm-2020-0084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 02/24/2020] [Indexed: 11/15/2022]
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Abstract
Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10-3) Ω-1 cm-1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10-3 Ω-1 cm-1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.
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Mechanical cell disruption of Parachlorella kessleri microalgae: Impact on lipid fraction composition. BIORESOURCE TECHNOLOGY 2018; 256:77-85. [PMID: 29433049 DOI: 10.1016/j.biortech.2018.01.148] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 06/08/2023]
Abstract
Samples of nitrogen-starved Parachlorella kessleri containing intact cells (IC), cells ground by bead milling (BM), and cells subjected to high-pressure cell disruption (HPD), together with their supernatants after centrifugation, were compared for granulometry and lipid profiles. The effects of disruption on the lipid profile and organisation were evaluated. The quantity of lipids available for extraction increased with disruption, and up to 81% could be recovered in supernatants after centrifugation, but a marked reorganization occurred. The proportion of amphiphilic free fatty acids and lysophosphatidylcholine increased during disruption due to their release or owing to lipid degradation by enzymes or physical conditions. This effect was more marked in HPD than in BM. Lipids contained in the aqueous phase, after disruption and centrifugation, were enriched in unsaturated fatty acids, BM leading to larger droplets than HPD. The larger liquid lipid droplet would be easier to recover in the following downstream processing.
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Host defense cathelicidins in cattle: types, production, bioactive functions and potential therapeutic and diagnostic applications. Int J Antimicrob Agents 2018; 51:813-821. [PMID: 29476808 DOI: 10.1016/j.ijantimicag.2018.02.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 02/07/2018] [Accepted: 02/11/2018] [Indexed: 12/22/2022]
Abstract
Cathelicidins are a primitive class of host defense peptides and are known for their broad-spectrum antimicrobial activity against bacteria, fungi, and enveloped viruses. These small, cationic, proteolytically-activated peptides are diverse in structure, encompassing a wide range of activities on host immune and inflammatory cell responses. The dual capacity of cathelicidins to directly control infection and regulate host defenses highlights the potential use of these peptides as alternatives to antibiotics and immunomodulators. Cathelicidins are found in many mammalian species; this review focuses on bovine cathelicidins. Eight naturally and two synthetically occurring bovine cathelicidins are described in detail, with a focus on recent advances in their expression, location and biological roles. This review also presents an overview of the bioactive functions of cathelicidins in bovine mastitis, a disease causing economic losses in cattle dairy production. Comparison of the structural, antimicrobial, cytotoxic and mechanistic properties of bovine cathelicidins advances the knowledge needed for the development of these peptides as potential identifiers of infectious diseases (e.g., bovine mastitis) and as novel therapeutic alternatives to antibiotics.
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Novel Concept of Gas Sensitivity Characterization of Materials Suited for Implementation in FET-Based Gas Sensors. NANOSCALE RESEARCH LETTERS 2016; 11:481. [PMID: 27804101 PMCID: PMC5089966 DOI: 10.1186/s11671-016-1687-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 10/11/2016] [Indexed: 06/06/2023]
Abstract
We propose a novel technique to investigate the gas sensitivity of materials for implementation in field-effect transistor-based gas sensors. Our technique is based on the measurement of the surface charge induced by gas species adsorption, using an electrometer. Platinum sensitivity to hydrogen diluted in synthetic air has been evaluated with the proposed charge measurement technique in the operation temperature range from 80 to 190 °C at constant H2 concentration of 4 % and for different concentrations ranging from 0.5 to 4 % at 130 °C.
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Chemical Composition of Nanoporous Layer Formed by Electrochemical Etching of p-Type GaAs. NANOSCALE RESEARCH LETTERS 2016; 11:446. [PMID: 27704487 PMCID: PMC5050177 DOI: 10.1186/s11671-016-1642-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/20/2016] [Indexed: 05/30/2023]
Abstract
We have performed a detailed characterization study of electrochemically etched p-type GaAs in a hydrofluoric acid-based electrolyte. The samples were investigated and characterized through cathodoluminescence (CL), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that after electrochemical etching, the porous layer showed a major decrease in the CL intensity and a change in chemical composition and in the crystalline phase. Contrary to previous reports on p-GaAs porosification, which stated that the formed layer is composed of porous GaAs, we report evidence that the porous layer is in fact mainly constituted of porous As2O3. Finally, a qualitative model is proposed to explain the porous As2O3 layer formation on p-GaAs substrate.
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Maintenance of ovulation inhibition with a new progestogen-only pill containing drospirenone after scheduled 24-h delays in pill intake. Contraception 2015; 93:303-309. [PMID: 26708301 DOI: 10.1016/j.contraception.2015.12.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 12/10/2015] [Accepted: 12/11/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Traditional progestogen-only pills (POPs) have stringent daily timing and missed pill rules that might affect contraceptive reliability. A new-generation oestrogen-free pill has been developed, containing 4-mg drospirenone with a unique regimen of 24 active treatment days followed by four placebo tablets. A previous study showed that this new drospirenone-only pill effectively inhibited ovulation. Clinical efficacy, however, can be affected by compliance, and delayed or forgotten pill intake often occurs in daily life. The aim of this study was to investigate if inhibition of ovulation was maintained after four scheduled 24-h delays in tablet intake. STUDY DESIGN One hundred thirty healthy women with proven ovulatory cycles were randomized, and 127 were treated with the drospirenone-only pill during two cycles. In treatment Group A (n=62), 24-h delays in tablet intake were scheduled on days 3, 6, 11 and 22 during Cycle 2 and, in treatment Group B (n=65) during Cycle 1, respectively. Ovulation was defined as disappearance or persistence of a large follicle and progesterone levels higher than 5 ng/mL for at least 5 consecutive days. RESULTS The overall ovulation rate was 0.8%; only one subject in Group A fulfilled the ovulation criteria in Cycle 2. Follicular diameters in the regular-intake and the delayed-intake cycles were similar. CONCLUSION Despite the 4-day hormone-free period and multiple intentional 24-h delays in tablet intake, ovulation inhibition was maintained. This property distinguishes this new-generation oestrogen-free pill from traditional POPs by allowing the same "safety window" or flexibility in intake as combined oral contraceptives without compromising contraceptive reliability. IMPLICATIONS Delayed or forgotten pill intake is very common. Ovulation inhibition by the new-generation oestrogen-free pill, containing 4-mg drospirenone for 24 days followed by a 4-day treatment-free period, was maintained despite four 24-h delays in tablet intake, so the impact of delayed intake on contraceptive reliability will be low.
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Drospirenone-only oral contraceptive: results from a multicenter noncomparative trial of efficacy, safety and tolerability. Contraception 2015; 92:439-44. [DOI: 10.1016/j.contraception.2015.07.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/23/2015] [Accepted: 07/26/2015] [Indexed: 10/23/2022]
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A randomised study comparing the effect on ovarian activity of a progestogen-only pill (POP) containing desogestrel and a new POP containing drospirenone in a 24/4 regimen. EUR J CONTRACEP REPR 2015; 20:419-27. [DOI: 10.3109/13625187.2015.1044082] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Space-charge limited transport in large-area monolayer hexagonal boron nitride. NANO LETTERS 2015; 15:2263-2268. [PMID: 25730309 DOI: 10.1021/nl504197c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Hexagonal boron nitride (hBN) is a wide-gap material that has attracted significant attention as an ideal dielectric substrate for 2D crystal heterostructures. We report here the first observation of in-plane charge transport in large-area monolayer hBN, grown by chemical vapor deposition. The quadratic scaling of current with voltage at high bias corresponds to a space-charge limited conduction mechanism, with a room-temperature mobility reaching up to 0.01 cm(2)/(V s) at electric fields up to 100 kV/cm in the absence of dielectric breakdown. The observation of in-plane charge transport highlights the semiconducting nature of monolayer hBN, and identifies hBN as a wide-gap 2D crystal capable of supporting charge transport at high field. Future exploration of charge transport in hBN is motivated by the fundamental study of UV optoelectronics and the massive Dirac fermion spectrum of hBN.
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A damascene platform for controlled ultra-thin nanowire fabrication. NANOTECHNOLOGY 2013; 24:245305. [PMID: 23696290 DOI: 10.1088/0957-4484/24/24/245305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This paper presents a damascene process for the fabrication of titanium micro/nanostructures and nanowires with adjustable thickness down to 2 nm. Their depth is precisely controlled by chemical-mechanical planarization together with in-process electrical characterization. The latter, in combination with a model of the titanium resistivity versus thickness, allows control of the metal line depth in the nanometer range. In summary, we have developed a planarization end point detection method for metal nanostructures. In addition, the model adopted covers geometrical influences like oxidation and ageing. The fabricated titanium nanowire test structures have a thickness ranging from 2 to 25 nm and a width ranging between 15 and 230 nm.
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Three-dimensional electron energy deposition modeling of cathodoluminescence emission near threading dislocations in GaN and electron-beam lithography exposure parameters for a PMMA resist. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:1220-1228. [PMID: 23146129 DOI: 10.1017/s1431927612013414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The Monte Carlo software CASINO has been expanded with new modules for the simulation of complex beam scanning patterns, for the simulation of cathodoluminescence (CL), and for the calculation of electron energy deposition in subregions of a three-dimensional (3D) volume. Two examples are presented of the application of these new capabilities of CASINO. First, the CL emission near threading dislocations in gallium nitride (GaN) was modeled. The CL emission simulation of threading dislocations in GaN demonstrated that a better signal-to-noise ratio was obtained with lower incident electron energy than with higher energy. Second, the capability to simulate the distribution of the deposited energy in 3D was used to determine exposure parameters for polymethylmethacrylate resist using electron-beam lithography (EBL). The energy deposition dose in the resist was compared for two different multibeam EBL schemes by changing the incident electron energy.
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Reduced workfunction intermetallic seed layers allow growth of porous n-GaN and low resistivity, ohmic electron transport. ACS APPLIED MATERIALS & INTERFACES 2012; 4:6927-6934. [PMID: 23167596 DOI: 10.1021/am3020668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Porous GaN crystals have been successfully grown and electrically contacted simultaneously on Pt- and Au-coated silicon substrates as porous crystals and as porous layers. By the direct reaction of metallic Ga and NH(3) gas through chemical vapor deposition, intermetallic metal-Ga alloys form at the GaN-metal interface, allowing vapor-solid-solid seeding and subsequent growth of porous GaN. Current-voltage and capacitance-voltage measurements confirm that the intermetallic seed layers prevent interface oxidation and give a high-quality reduced workfunction contact that allows exceptionally low contact resistivities. Additionally, the simultaneous formation of a lower workfunction intermetallic permits ohmic electron transport to n-type GaN grown using high workfunction metals that best catalyze the formation of porous GaN layers and may be employed to seed and ohmically contact a range of III-N compounds and alloys for broadband absorption and emission.
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Chemical vapor deposition of porous GaN particles on silicon. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:905-911. [PMID: 22831653 DOI: 10.1017/s1431927612001134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a technique for the direct deposition of nanoporous GaN particles on Si substrates without requiring any post-growth treatment. The internal morphology of the nanoporous GaN particles deposited on Si substrates by using a simple chemical vapor deposition approach was investigated, and straight nanopores with diameters ranging between 50 and 100 nm were observed. Cathodoluminescence characterization revealed a sharp and well-defined near band-edge emission at ∼365 nm. This approach simplifies other methods used for this purpose, such as etching and corrosion techniques that can damage the semiconductor structure and modify its properties.
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The probe profile and lateral resolution of scanning transmission electron microscopy of thick specimens. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:582-90. [PMID: 22564444 PMCID: PMC3389604 DOI: 10.1017/s1431927612000232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as a function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as a function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 μm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens.
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Effect of Thermal Annealing on the Kinetics of Rehydroxylation of Eu3+:La2O3 Nanocrystals. Inorg Chem 2012; 51:6139-46. [DOI: 10.1021/ic300108f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Three-dimensional electron microscopy simulation with the CASINO Monte Carlo software. SCANNING 2011; 33:135-46. [PMID: 21769885 PMCID: PMC3164775 DOI: 10.1002/sca.20262] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 06/07/2011] [Indexed: 05/24/2023]
Abstract
Monte Carlo softwares are widely used to understand the capabilities of electron microscopes. To study more realistic applications with complex samples, 3D Monte Carlo softwares are needed. In this article, the development of the 3D version of CASINO is presented. The software feature a graphical user interface, an efficient (in relation to simulation time and memory use) 3D simulation model, accurate physic models for electron microscopy applications, and it is available freely to the scientific community at this website: www.gel.usherbrooke.ca/casino/index.html. It can be used to model backscattered, secondary, and transmitted electron signals as well as absorbed energy. The software features like scan points and shot noise allow the simulation and study of realistic experimental conditions. This software has an improved energy range for scanning electron microscopy and scanning transmission electron microscopy applications.
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Simulating STEM imaging of nanoparticles in micrometers-thick substrates. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:795-804. [PMID: 20961483 PMCID: PMC3165039 DOI: 10.1017/s1431927610094080] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Scanning transmission electron microscope (STEM) images of three-dimensional (3D) samples were simulated. The samples consisted of a micrometer(s)-thick substrate and gold nanoparticles at various vertical positions. The atomic number (Z) contrast as obtained via the annular dark-field detector was generated. The simulations were carried out using the Monte Carlo method in the CASINO software (freeware). The software was adapted to include the STEM imaging modality, including the noise characteristics of the electron source, the conical shape of the beam, and 3D scanning. Simulated STEM images of nanoparticles on a carbon substrate revealed the influence of the electron dose on the visibility of the nanoparticles. The 3D datasets obtained by simulating focal series showed the effect of beam broadening on the spatial resolution and on the signal-to-noise ratio. Monte Carlo simulations of STEM imaging of nanoparticles on a thick water layer were compared with experimental data by programming the exact sample geometry. The simulated image corresponded to the experimental image, and the signal-to-noise levels were similar. The Monte Carlo simulation strategy described here can be used to calculate STEM images of objects of an arbitrary geometry and amorphous sample composition. This information can then be used, for example, to optimize the microscope settings for imaging sessions where a low electron dose is crucial for the design of equipment, or for the analysis of the composition of a certain specimen.
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Simulating STEM imaging of nanoparticles in micrometers-thick substrates. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:795-804. [PMID: 20961483 DOI: 10.1017/s1431927611005770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Scanning transmission electron microscope (STEM) images of three-dimensional (3D) samples were simulated. The samples consisted of a micrometer(s)-thick substrate and gold nanoparticles at various vertical positions. The atomic number (Z) contrast as obtained via the annular dark-field detector was generated. The simulations were carried out using the Monte Carlo method in the CASINO software (freeware). The software was adapted to include the STEM imaging modality, including the noise characteristics of the electron source, the conical shape of the beam, and 3D scanning. Simulated STEM images of nanoparticles on a carbon substrate revealed the influence of the electron dose on the visibility of the nanoparticles. The 3D datasets obtained by simulating focal series showed the effect of beam broadening on the spatial resolution and on the signal-to-noise ratio. Monte Carlo simulations of STEM imaging of nanoparticles on a thick water layer were compared with experimental data by programming the exact sample geometry. The simulated image corresponded to the experimental image, and the signal-to-noise levels were similar. The Monte Carlo simulation strategy described here can be used to calculate STEM images of objects of an arbitrary geometry and amorphous sample composition. This information can then be used, for example, to optimize the microscope settings for imaging sessions where a low electron dose is crucial for the design of equipment, or for the analysis of the composition of a certain specimen.
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Anti-angiogenic assay assists fetal extraction decision in a case of pre-eclampsia suspicion? Clin Kidney J 2010; 3:427-8. [PMID: 25949457 PMCID: PMC4421524 DOI: 10.1093/ndtplus/sfq099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 04/30/2010] [Accepted: 05/12/2010] [Indexed: 12/03/2022] Open
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Nanometer-resolution electron microscopy through micrometers-thick water layers. Ultramicroscopy 2010; 110:1114-9. [PMID: 20542380 DOI: 10.1016/j.ultramic.2010.04.001] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Revised: 03/17/2010] [Accepted: 04/05/2010] [Indexed: 11/29/2022]
Abstract
Scanning transmission electron microscopy (STEM) was used to image gold nanoparticles on top of and below saline water layers of several micrometers thickness. The smallest gold nanoparticles studied had diameters of 1.4 nm and were visible for a liquid thickness of up to 3.3 microm. The imaging of gold nanoparticles below several micrometers of liquid was limited by broadening of the electron probe caused by scattering of the electron beam in the liquid. The experimental data corresponded to analytical models of the resolution and of the electron probe broadening as function of the liquid thickness. The results were also compared with Monte Carlo simulations of the STEM imaging on modeled specimens of similar geometry and composition as used for the experiments. Applications of STEM imaging in liquid can be found in cell biology, e.g., to study tagged proteins in whole eukaryotic cells in liquid and in materials science to study the interaction of solid:liquid interfaces at the nanoscale.
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Photoluminescence and cathodoluminescence of Eu: La2O3 nanoparticles synthesized by several methods. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.phpro.2010.10.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Le transfert des connaissances et la mise en œuvre de lignes directrices de pratique Expérience du Programme d’Éducation Canadien sur l’Hypertension. Nephrol Ther 2009; 5 Suppl 4:S246-9. [DOI: 10.1016/s1769-7255(09)74553-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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35
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Time to do more: Feedback based national glycaemic treatment optimization program can improve attainment of glycaemic targets. Can J Diabetes 2009. [DOI: 10.1016/s1499-2671(09)33044-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Private drug coverage is not associated with better attainment of glycaemic targets in a Canadian glycaemic treatment optimization program. Can J Diabetes 2009. [DOI: 10.1016/s1499-2671(09)33208-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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37
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Etazolate, a neuroprotective drug linking GABA(A) receptor pharmacology to amyloid precursor protein processing. J Neurochem 2008; 106:392-404. [PMID: 18397369 DOI: 10.1111/j.1471-4159.2008.05396.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Pharmacological modulation of the GABA(A) receptor has gained increasing attention as a potential treatment for central processes affected in Alzheimer disease (AD), including neuronal survival and cognition. The proteolytic cleavage of the amyloid precursor protein (APP) through the alpha-secretase pathway decreases in AD, concurrent with cognitive impairment. This APP cleavage occurs within the beta-amyloid peptide (Abeta) sequence, precluding formation of amyloidogenic peptides and leading to the release of the soluble N-terminal APP fragment (sAPPalpha) which is neurotrophic and procognitive. In this study, we show that at nanomolar-low micromolar concentrations, etazolate, a selective GABA(A) receptor modulator, stimulates sAPPalpha production in rat cortical neurons and in guinea pig brains. Etazolate (20 nM-2 microM) dose-dependently protected rat cortical neurons against Abeta-induced toxicity. The neuroprotective effects of etazolate were fully blocked by GABA(A) receptor antagonists indicating that this neuroprotection was due to GABA(A) receptor signalling. Baclofen, a GABA(B) receptor agonist failed to inhibit the Abeta-induced neuronal death. Furthermore, both pharmacological alpha-secretase pathway inhibition and sAPPalpha immunoneutralization approaches prevented etazolate neuroprotection against Abeta, indicating that etazolate exerts its neuroprotective effect via sAPPalpha induction. Our findings therefore indicate a relationship between GABA(A) receptor signalling, the alpha-secretase pathway and neuroprotection, documenting a new therapeutic approach for AD treatment.
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P2‐325: EHT0202, an alpha‐secretase stimulator active against amyloid‐beta accumulation and neurotoxicity that improves attention and cognition. Alzheimers Dement 2008. [DOI: 10.1016/j.jalz.2008.05.1402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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39
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P1‐343: Discovery of blood gene expression biomarkers in Alzheimer's disease using the human genome‐wide splice array. Alzheimers Dement 2008. [DOI: 10.1016/j.jalz.2008.05.924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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CASINO V2.42: a fast and easy-to-use modeling tool for scanning electron microscopy and microanalysis users. SCANNING 2007; 29:92-101. [PMID: 17455283 DOI: 10.1002/sca.20000] [Citation(s) in RCA: 395] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Monte Carlo simulations have been widely used by microscopists for the last few decades. In the beginning it was a tedious and slow process, requiring a high level of computer skills from users and long computational times. Recent progress in the microelectronics industry now provides researchers with affordable desktop computers with clock rates greater than 3 GHz. With this type of computing power routinely available, Monte Carlo simulation is no longer an exclusive or long (overnight) process. The aim of this paper is to present a new user-friendly simulation program based on the earlier CASINO Monte Carlo program. The intent of this software is to assist scanning electron microscope users in interpretation of imaging and microanalysis and also with more advanced procedures including electron-beam lithography. This version uses a new architecture that provides results twice as quickly. This program is freely available to the scientific community and can be downloaded from the website: (www.gel.usherb.ca/casino).
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RAC1 inhibition targets amyloid precursor protein processing by gamma-secretase and decreases Abeta production in vitro and in vivo. J Biol Chem 2005; 280:37516-25. [PMID: 16150730 DOI: 10.1074/jbc.m507913200] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
beta-Amyloid peptides (Abeta) that form the senile plaques of Alzheimer disease consist mainly of 40- and 42-amino acid (Abeta 40 and Abeta 42) peptides generated from the cleavage of the amyloid precursor protein (APP). Generation of Abeta involves beta-secretase and gamma-secretase activities and is regulated by membrane trafficking of the proteins involved in Abeta production. Here we describe a new small molecule, EHT 1864, which blocks the Rac1 signaling pathways. In vitro, EHT 1864 blocks Abeta 40 and Abeta 42 production but does not impact sAPPalpha levels and does not inhibit beta-secretase. Rather, EHT 1864 modulates APP processing at the level of gamma-secretase to prevent Abeta 40 and Abeta 42 generation. This effect does not result from a direct inhibition of the gamma-secretase activity and is specific for APP cleavage, since EHT 1864 does not affect Notch cleavage. In vivo, EHT 1864 significantly reduces Abeta 40 and Abeta 42 levels in guinea pig brains at a threshold that is compatible with delaying plaque accumulation and/or clearing the existing plaque in brain. EHT 1864 is the first derivative of a new chemical series that consists of candidates for inhibiting Abeta formation in the brain of AD patients. Our findings represent the first pharmacological validation of Rac1 signaling as a target for developing novel therapies for Alzheimer disease.
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The impact of charging on low-energy electron beam lithography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2004; 10:804-809. [PMID: 19780323 DOI: 10.1017/s1431927604040711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A major issue in low voltage lithography is surface charging, which results in beam deflection presented as uneven exposure between adjacent structures. In this study, charge-induced pattern distortions in low-voltage energy beam lithography (LVEBL) were investigated using a silicide direct-write electron beam lithography process. Two methodologies have been proposed to avert charging effects in LVEBL, namely, pattern randomizing and lithography using the crossover voltage. Experimental results demonstrated that these methods are effective in significantly reducing the problems associated with charging. They indicate that charging on a sample is a function of time interval and proximity between line structures. In addition, the optimum time and distance between exposures for no charge-induced pattern distortion were determined. By using the crossover voltage of the material for lithography, charging effect can be significantly minimized.
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Effect of Iron Catalyst on the Synthesis of Fullerenes and Carbon Nanotubes in Induction Plasma. J Phys Chem B 2004. [DOI: 10.1021/jp047629z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Implementing hypertension recommendations. Can J Cardiol 2001; 17:851-6. [PMID: 11521126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
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The effect of fast secondary electrons on x-ray microanalysis in the scanning electron microscope. SCANNING 1999; 21:238-245. [PMID: 10483878 DOI: 10.1002/sca.4950210403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this paper, the effect of fast secondary electrons (FSE), which result from inelastic scattering of incident electrons, on the characterization of materials in the scanning electron microscope are investigated with the aid of Monte Carlo simulations. The effect of FSE on x-ray microanalysis of light elements is investigated. A full description of the Monte Carlo simulations of FSE in solids is given.
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An interactive workshop: An effective means of integrating the Canadian Cardiovascular Society clinical practice guidelines on congestive heart failure into Canadian family physicians' practice. Can J Cardiol 1998; 14:911-6. [PMID: 9706275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE To use an interactive workship as a means of integrating clinical practice guidelines on congestive heart failure into Canadian family physicians' practice. SETTING Interested practitioners from the Association des Médecins Omnipraticiens de Québec, the Centre de Santé Publique de Québec and the continuing medical education (CME) department, Merck Frosst Canada, Montreal, formed the initial task force. Train-the-trainer sessions took place in many provinces in a variety of CME settings. DESIGN The interactive, problem-based workshop was facilitated by local interested general practitioners, while local experts served as consultants to reinforce key messages from clinical practice guidelines and to guide participants through the learning process. MAIN RESULTS By December 31, 1996, 187 family practitioners and 81 specialists had been trained in train-the-trainer sessions across the country. A total of 1698 general practitioners had participated in over 52 workshops during the same time. Pre- and postworkshop testing indicate that the workshops improved knowledge, and that the knowledge gained during the workshop was retained at three- and six-months' follow-up. Separate chart evaluations conducted before and after the workshop showed that participants provided more complete chart information related to congestive heart failure and that they significantly increased their use of angiotensin-converting enzyme inhibitor therapy after the workshop. Participant evaluation of the workshop also indicates a high index of satisfaction with the presentation and the content of the workshop as being relevant to clinical practice. CONCLUSION An interactive, problem-based, small group workshop developed by a core group of interested practitioners and guided by local trained facilitators and experts is an effective teaching tool through which clinical practice guidelines can be successfully transferred into clinical practice in a timely and meaningful way.
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Abstract
This exploratory study uses Andersen's service utilization model to examine the relationship between the leisure activity patterns of older people and their knowledge and use of health and social services. Hierarchical stepwise multiple regression analyses of data from 418 people ages 65 and older in rural Qu/ebec revealed that leisure activity patterns may explain a greater amount of variation in service knowledge and use than conventional need characteristics such as physical and psychological health. Various activity patterns were significantly related to knowledge and use of services even after controlling for variables such as age and health status. Although some types of leisure activities appeared to augment knowledge and use of services, others seemed to deter it. Future explanatory models of service utilization among the elderly should be expanded to include leisure activity patterns.
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KNOWLEDGE EVALUATION IN POST-HI PATIENTS FOLLOWING PHASE I AND PHASE II OF REHABILITATION. Med Sci Sports Exerc 1986. [DOI: 10.1249/00005768-198604001-00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Design of sterile muramyldipeptide-containing oligolamellar liposomes suitable for i.v. injection. Effect of liposome size and lipid composition on their ability to render peritoneal macrophages antitumoral. Int J Pharm 1985. [DOI: 10.1016/0378-5173(85)90158-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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